WO2009039681A1 - A power apparatus for oil-electricity hybrid vehicle and the operation control method thereof - Google Patents

Abstract

A power apparatus for an oil-electricity hybrid vehicle and the operation control method thereof are provided. The power apparatus includes an engine (1), a motor unit composed of a first motor and a second motor, an output gear (9), a reduction gear (8), a differential (7), and a main control unit (17). A first servo driver (18) and a second servo driver (15) are provided to execute the servo control to the first motor and the second motor according to the operating condition. The main control unit can calculate the matched torque corresponding to the prestored optical economical engine operation graph and send the corresponding torque setting value to the first servo driver, and send a torque setting value to the second servo driver according to the vehicle driving condition or the driving requirements. This kind of servo control system of the motor unit can realize the independent adjusting of engine operation points so as to precisely control the load torque applied to the engine by the motors. Therefore the engine can be controlled to operate economically according to the optimal fuel efficiency graph.

Description

 Power structure of hybrid electric vehicle and operation control method thereof

 The invention relates to a power structure of a hybrid electric vehicle, in particular to a power structure of a cascade motor assembly and a servo system using a dual motor; the invention also relates to an operation control of a power structure of a hybrid electric vehicle method. Background technique

 Pure fuel vehicles are attracting people's attention due to their high fuel consumption and large exhaust emissions. Research shows that the fuel-efficient ratio of hybrid electric vehicles can reach more than 50%, and the emission of exhaust gas is significantly reduced. It is a realistic and feasible energy-saving vehicle. The hybrid electric vehicle is a combination of mechanical energy and electric energy. Because it can adjust the engine operating point and recoverable braking energy, it can improve the utilization of fuel energy, so energy saving and low exhaust emissions. The existing hybrid electric vehicles have three common power structures: series, parallel, and hybrid. These three structures have their own characteristics and limitations.

 Figure 1 is a schematic block diagram of the existing series power structure and energy flow. The engine 57 is connected to the generator 56. The mechanical kinetic energy is all used for generating electricity by the generator 56. The power generation can be distributed by the controller 55, a part of which is supplied to the motor 53 to drive the vehicle, and another part of which flows to the storage battery 54. The battery 54 can be supplied as needed. Energy; The motor 53 can operate in four quadrants, recovers braking energy and stores it in the battery 54. Its characteristics are: (1) The motor 53 directly drives the vehicle, so the engine 57 is independent of the vehicle operating conditions, and the energy saving purpose achieved by the operating point of the engine 57 can be adjusted as needed; (2) The kinetic energy of the engine 57 passes through the generator 56 and the motor 53. Double losses, even if the efficiency of generator 56 and motor 53 is as high as 90%, the efficiency of engine 57 for driving can only reach 81%, and the total efficiency is lower at low speed. (3) The engine 57 does not directly drive the vehicle. In order to ensure the power of the vehicle, it is necessary to equip the high-power generator 56 and the electric motor 53 equivalent to the power of the engine 57, so that the weight and cost of the power structure are increased, and the energy saved is not easy. Lost by its own weight.

Figure 2 is a schematic block diagram of a prior art parallel power structure and energy flow. The engine 57 and the motor 53 are connected to the vehicle drive shaft through the coupling 58. The kinetic energy of the engine 57 can be used to drive the automobile, and the motor 53 can operate in the four-quadrant state. The engine 57 and the motor 53 can each independently or jointly work to drive the vehicle. Double as a generator to recover braking energy and charge the battery. Its characteristics are: (1) engine 57 speed is still with the car The speed change, the operating point of the engine 57 is limited by the motor 53, and the energy saving effect is compromised. (2) Since the engine 57 and the electric motor 54 are driven together, the power, particularly the acceleration, of the automobile is improved, and there is also the possibility of improving the economy by adapting the small displacement engine. (3) The engine 57 and the motor 53 are more complicated in connection with the shaft, and generally need to be equipped with a transmission. The overall power structure is still complicated.

 Figure 3 is a schematic block diagram of a conventional series-parallel hybrid power structure and energy flow. The structure is integrated with the characteristics of series and parallel. Compared with the series type, the engine 57 is added to participate in the drive to improve the power; compared with the parallel type, the transmission line for increasing the electric energy can conveniently adjust the operation of the engine 57. point. The performance is further improved than the series and parallel type, but the structure includes multiple power source couplings and transmission 59, etc. The structure is more complicated, the control is more complicated, the cost is higher, and the situation of "saving fuel is not saved" occurs.

The patent application EP0820894A2 of Hitachi, published on July 22, 1997 and published on October 26, 1999, discloses a hybrid transmission scheme for a continuously variable transmission, using two inverters to control the motor. The two inverters are actually two frequency converters. The main and auxiliary two motors are connected to the respective inverters, and under the control of the control unit, the high-efficiency stepless speed regulation and torque adjustment between the input shaft and the output shaft are realized; the gear ratio control through the stepless transmission makes the motor The system operates in any torque and speed range. However, because the patent application still uses the inverter drive scheme, the accuracy and response speed of the torque control are greatly reduced. In addition, by adjusting the stepless gear ratio control, the engine speed and torque follow the change of the external load, so that the engine working point can not work stably with the external load and stabilize the work on the optimal efficiency curve, but only the engine can work. The point is adjusted to a relatively high efficiency triangular region. However, there is also an optimal economic operation line in the economic region. At the speed-torque matching point characterized by the running line, the fuel is converted to mechanical energy with the highest efficiency. In view of the fact that the application of the present invention can only adjust the operating point of the engine to a relatively economical operating region, the effect that the engine operating point does not work stably with the external load on the optimum efficiency curve cannot be achieved. Therefore, there is still room for improvement in the patent application to adjust the engine operating point to achieve fuel economy. Furthermore, the patent application attempts to adjust the speed and torque output of the motor over a wide range when adjusting the stepless transmission gear ratio, but the output can only be within the nominal maximum speed and torque range of the motor and must be subject to frequency conversion. The maximum output voltage and maximum output current limit, if you want to achieve better power performance, you can only increase the capacity of the motor and inverter. In addition, in the patent application, the energy storage battery is directly connected to the common DC bus connected to the two frequency converters, and the dynamic process of charging and discharging the battery is inevitable. It is free, and the charging or discharging process of the battery is not directly controllable, so unnecessary charging and discharging loss is generated, and damage may be caused by uncontrollable charging and discharging current.

 U.S. Patent No. 5,973,460, issued to the U.S. Patent No. 5,973, 460, issued to A.S.A. The first drive circuit and the second drive circuit employed in this patent document are actually two frequency converters. Driven by the respective inverters, there is sufficient output at startup without damaging the battery and reducing the size of the motor. In addition, the two frequency converters can adjust the operating point of the engine by adjusting the torque of the respective motor for economic operation. However, the patented inverter technology used in the adjustment of torque is not sufficient for precise and rapid adjustment. In particular, when controlling the clutch motor, a rotatable transformer structure is employed to transfer electrical energy from the primary coil to the secondary coil by electromagnetic induction in an attempt to provide reliable current control to the rotating armature winding, but the transformer The mode of transmitting energy determines that the structure cannot perform effective winding current control with relatively low relative rotational speed between the two rotors of the clutch motor, and thus it is impossible to perform precise torque control of the clutch motor. Specifically, when the relative rotational speeds of the inner and outer rotors are low, the transformer will operate at a very low frequency, and the efficiency of the energy transfer and the energy per unit volume of the electromagnetic induction transformer in the case of low frequency power supply The size is very low, especially when the relative rotational speed of the inner rotor and the outer rotor is zero, the primary and secondary sides of the transformer will be direct current (that is, the current alternating frequency is zero), and the primary side is installed. The first drive circuit can not effectively control the current of the secondary side of the transformer (ie, the current of the motor winding), of course, it can not implement effective torque control on the motor, of course, the engine can always work optimally. Efficiency point.

 In summary, in other words, the following problems still exist in the power transmission of hybrid vehicles: 1 How to make the engine work on the optimal economic running curve, high fuel utilization; 2 How to control the generator under most operating conditions All the energy emitted is used to drive the motor, avoiding the charging and discharging energy loss of charging the battery and discharging from the battery; 3 how to obtain a larger short-time output torque and torque variation gradient to improve the acceleration performance and reaction speed of the vehicle; The output torque is precisely and quickly adjusted to facilitate various drive control strategies. Summary of the invention

In order to overcome the shortcomings in the prior art that the engine fails to regulate the operation of the optimal economic operation line The invention discloses a power structure of a hybrid electric vehicle, and the power structure of the hybrid electric vehicle can realize independent and precise adjustment of the working point of the engine, so that the working point does not follow The external load affects and works stably on the optimal efficiency curve. And the servo control system adopting the cascade motor assembly has more flexible maneuverability for the output of the hybrid vehicle.

 The solution to the above technical problem is to provide a power structure of a hybrid electric vehicle, comprising: an engine, a motor group composed of a first motor and a second motor, an output gear, a reduction gear and a differential, Wherein the first electric machine includes a first rotor and a second rotor electromagnetically coupled to each other, the second electric machine includes a mutually coupled electromagnetically coupled stator and a third rotor, the shaft of the first rotor being an input shaft of the cascaded motor assembly, the second The shaft of the rotor is coaxial with the third rotor and serves as an output shaft of the cascade motor assembly. The shaft of the first rotor is directly connected to the output shaft of the engine, and an output is mounted on the output shaft between the first and second motors. A gear, the output gear is coupled to the differential via a reduction gear, the differential being coupled to a drive shaft that connects the wheels. The power structure of the hybrid electric vehicle further includes a main control unit, a first servo drive associated with the first motor, and a second servo drive associated with the second motor, the first servo drive being operated according to a running condition The coupling torque between the first rotor and the second rotor is servo-controlled; the second servo driver performs servo control on the coupling torque between the stator and the third rotor according to the operation condition; the main control unit is used for pre-preserving according to the engine speed The optimal economic operating curve of the engine calculates a corresponding matching torque, sends a corresponding torque setting to the first servo drive, and sends a torque setting to the second servo drive according to the running condition or driving requirement of the vehicle.

Compared with the prior art inverter-based control scheme, the present invention employs torque servo control, which can be applied to the engine regardless of whether the first and second rotors of the first motor rotate or not, and the relative speed of rotation. The load torque is precisely controlled, making it easy to control the engine on its optimum fuel efficiency curve for the most economical operation. Moreover, the first servo drive can precisely control the first motor due to its own "servo" control characteristic, and then perform precise torque servo control on the first motor. In U.S. Patent No. 5,973,460, the method adopted by the conventional inverter is 3 - 2 and 2 - 3 vector analysis, and the control of the clutch motor is even inserted into the energy transfer of the resolver. Control mode, so far has not been able to like this The invention uses the servo control technology to accurately control the theoretical analysis of the motor torque and the actual production port.

 The technical problem further solved by the present invention is to reduce the energy dissipation of the system. The further solved technical problem is achieved by the following further technical solution, that is, one of the first rotor and the second rotor is mounted on one of the first rotor and the second rotor. a permanent magnet pole, a first winding wound on the iron core is mounted on the other of the first rotor and the second rotor; and a permanent magnet pole is mounted on one of the third rotor and the stator, A second winding wound on the core is mounted on the other of the third rotor and the stator. The first winding is connected to the first servo driver through a slip ring mounted on the shaft thereof to obtain a control current to the first servo driver; the second winding is disposed on the stator and directly connected to the second servo driver Connected, or disposed on the third rotor and connected to the second servo drive via a slip ring mounted on the output shaft. Since the collector ring is in direct contact with the conductor, the purpose of the collector ring is to directly send the current sent by the servo driver to the corresponding winding of the motor. In this way, there is almost no energy loss except for friction heating and contact resistance heating. In U.S. Patent No. 5,973,460, the transformer structure employed, even if the energy can be transferred at the rated operating frequency point (i.e., the relative rotational speed of the inner rotor and the outer rotor is the rated speed), the energy transfer efficiency is not as good as the present invention.

 According to another aspect of the present invention, the power structure of the hybrid electric vehicle further includes an engine control unit that can receive a signal from the main control unit to perform speed control or start and stop control on the engine.

 According to another aspect of the invention, a first speed/position sensor is mounted on the shaft of the first rotor, the first speed/position sensor being coupled to the first servo drive; on a common axis of the second rotor and the third rotor a second speed/position sensor is mounted, the second speed/position sensor being coupled to the first and second servo drives, the first servo driver responsive to the torque setting and the feedback signal pair of the first and second speed/position sensors Coupling torque between the first rotor and the second rotor is servo controlled to achieve independent adjustment of the engine operating point independently of the vehicle operating state; the second servo drive is responsive to the torque setting and the second speed/position sensor The feedback signal servo-controls the coupling torque between the stator and the third rotor to drive the second motor to the entire vehicle.

According to another aspect of the present invention, the first motor is a permanent magnet synchronous motor, wherein a permanent magnet pole is mounted on one of the first rotor and the second rotor, in the first rotor and the second rotor One of the other is mounted with a first winding wound on the core; The second motor is a permanent magnet synchronous motor, wherein a permanent magnet pole is mounted on one of the third rotor and the stator, and a wound core is mounted on the other of the third rotor and the stator The second winding on.

 According to another aspect of the invention, the first and second motors are permanent magnet synchronous motors or brushless DC motors.

 According to another aspect of the present invention, the first servo driver and the first servo driver are connected by a common DC bus, and the common DC bus is also connected to the energy storage unit for acquiring power from the DC bus according to the requirements of the main control unit and its own charging and discharging strategy. Within or from which electrical energy is drawn to the DC bus. The energy storage unit includes a capacitor, a battery, and a charge and discharge control and protection circuit thereof.

 According to another aspect of the present invention, the main control unit body is a computer that stores data relating to accelerator pedal opening degree and driving torque setting value, energy storage unit voltage and charging demand power relationship data, and brake pedal opening degree. The brake torque relationship data, the shift control program, the main control unit externally connected to the accelerator pedal opening degree sensor, the brake pedal angle sensor, and various control command switches. The control unit controls the first servo drive and/or the second servo drive according to at least one of the following data stored therein, thereby controlling the operation of the first motor and/or the second motor: the speed on the optimal efficiency curve of the engine - Torque matching data, power upper and lower limits of the economic operating zone of the optimal efficiency curve, relationship between the accelerator pedal angle and the driving torque set value, energy storage unit voltage and charging demand power relationship data, brake pedal angle and braking Torque relationship data and shift control program.

 According to another aspect of the present invention, when the hybrid vehicle is started, the main control unit controls the first servo driver such that the interaction torque between the first rotor and the second rotor of the first motor is zero, and according to the accelerator pedal The relationship between the angle and the driving torque setting value is controlled by the second servo driver to torque the second motor, and the starting driving torque is output; after starting, when the sum of the driving power demand and the energy storage unit charging power demand is greater than a preset threshold value Informing the engine control unit to start engine operation;

According to another aspect of the present invention, when a normal driving drive is applied to the hybrid vehicle, the main control unit controls the engine to operate on the optimal economic running curve through the first motor system on the one hand, and controls the second motor system according to the driving demand on the other hand. Output torque. In most operating situations, the first motor system power generation is all used for the second motor system drive, or the second motor system power generation is all used for the first motor system drive, unless the energy storage unit is controlled according to its own control strategy. The main control unit commands and actively proposes charging and discharging requirements. All power generation does not pass through the charging and discharging process of the energy storage unit.

 According to another aspect of the present invention, when braking is applied to the hybrid vehicle, the main control unit controls the first motor system to output zero torque according to the brake pedal angle or the same load torque pair that does not cause the engine to be turned off and the engine steering is the same. The power car is implemented with limited dynamic braking, and the second motor is controlled to output the braking torque to the outside by the second servo driver according to the brake pedal angle and the braking torque.

 According to another aspect of the invention, when braking, the external load kinetic energy is converted into electrical energy by the first motor system or the second motor system and the electrical energy is delivered to the DC bus, and the energy storage unit actively obtains electrical energy from the common DC bus to store it. Inside.

 According to another aspect of the present invention, if the power of the recovered electric energy is too large during braking, the charging process of the energy storage unit is too late to absorb the energy, causing the DC bus voltage to rise to a predetermined value; or the excess energy is recovered, the energy storage unit is insufficient When these energy are stored and the DC bus voltage rises to a predetermined value, the energy bleed protection device inside the energy storage unit starts to bleed, and the excess energy is converted into heat energy through the braking resistor.

 According to another aspect of the present invention, when reversing, the main control unit controls the first servo driver according to the reverse running demand and the accelerator pedal angle such that the interaction torque between the first rotor and the second rotor of the first motor is zero; The second motor outputs the reverse driving torque through the second servo driver according to the accelerator pedal angle and the driving torque set value relationship.

 According to another aspect of the present invention, when a relative change occurs between the total output torque of the output shaft of the dual motor and the load torque of the vehicle, the vehicle speed automatically changes steplessly, and the total output torque is controlled only by the main control unit and each servo drive. Not directly related to the speed of the car.

 According to still another aspect of the present invention, when the driver changes the accelerator pedal angle, the engine speed changes accordingly, and the first motor transmission torque also changes accordingly, and the main control unit controls the second motor system to output the corresponding torque to achieve the output torque. Stepless adjustment. The main control unit controls the second motor system to output short-time overload torque according to the speed and angle of the accelerator pedal and the short-time overload capacity of the second motor system, so as to improve the dynamic performance and operational sensitivity of the vehicle.

The power structure of the hybrid electric vehicle further has the advantages that: the magnetic fields of the first and second electric machines are independent of each other, so that the engine can be independently loaded with appropriate torque without disturbing each other, so that the engine works at the optimal efficiency curve. In the above, the consumption of the same amount of fuel can obtain greater kinetic energy; the engine kinetic energy can be transmitted by electromagnetic direct coupling and electric energy to improve the transmission efficiency, recover the braking energy, improve the energy utilization rate, and generally improve the fuel chemical energy utilization rate; Multiple powers can be flexibly combined for better dynamic performance; continuous, fast shifting and torque-changing through servo control of dual motors; furthermore, the clutch, gearbox, and multiple power sources are eliminated by electromagnetic force without gear coupling. The mechanical structure of the whole vehicle is simplified, the processing is convenient, the cost is low, and it is suitable for popularization and application.

 The present invention also provides a control operation method for a power structure of a hybrid electric vehicle: wherein the power structure of the hybrid electric vehicle includes: an engine, a motor group composed of a first motor and a second motor, and an output gear a reduction gear and a differential, wherein the first electric machine includes a first rotor and a second rotor electromagnetically coupled to each other, the second electric machine including a stator and a third rotor electromagnetically coupled to each other, the shaft of the first rotor being the cascade motor An input shaft of the assembly, the shaft of the second rotor is coaxial with the third rotor and serves as an output shaft of the cascade motor assembly, the shaft of the first rotor is directly connected to the output shaft of the engine, between the first and second motors An output gear is mounted on the output shaft, and the output gear is connected to the differential via a reduction gear, and the differential is connected to a drive shaft connecting the wheels, and the power structure of the hybrid electric vehicle further includes a main control unit, and a first servo driver associated with the first motor and a second servo driver associated with the second motor, the operation control method comprising the following steps The main control unit calculates a corresponding matching torque according to the pre-stored optimal economic operation curve of the engine according to the engine speed, sends a corresponding torque setting to the first servo drive, and applies the second servo drive according to the running condition or driving requirement of the vehicle. Sending a torque setting; the first servo driver performs servo control on a coupling torque between the first rotor and the second rotor according to an operation condition, and the second servo driver performs a coupling torque between the stator and the third rotor according to an operation condition Servo Control.

According to an aspect of the operation control method of the present invention, the step of servo-controlling the coupling torque between the first rotor and the second rotor includes the following steps: The first servo driver acquires the absolute position of the first rotor from the first speed/position sensor The signal θ _{1 5} acquires the absolute position signal θ _{2 of the} second rotor from the second speed/position sensor, and obtains a position angle ( θ ₂ ) of the first rotor relative to the second rotor; the current vector is in phase with the back potential vector Principle to obtain the direction of the first winding current vector; read the torque set value from the control unit, calculate the magnitude of the current vector; find the instantaneous setpoints i _al , i _bl , i _{cl of the} three-phase current; Current closed loop control; and drive power amplification circuit. Wherein, when the hybrid vehicle is started, the main control unit controls the first servo driver such that the interaction torque between the first rotor and the second rotor of the first motor is zero.

According to another aspect of the operation control method of the present invention, between the stator and the third rotor The step of performing the servo control by the coupling torque includes the following steps: the second servo driver acquires the absolute position signal Θ _{2 of the} third rotor from the second speed/position sensor; and obtains the second winding current according to the principle that the current vector is in phase with the back potential vector The direction of the vector; reading the torque set value from the control unit, calculating the magnitude of the current vector; obtaining the instantaneous setpoints i _a2 , i _b2 , i _c2 of the three-phase current; respectively performing three-phase current closed-loop control; Power amplifier circuit. Wherein, when the hybrid vehicle is started, the second motor is torque-controlled by the second servo driver according to the relationship between the accelerator pedal angle and the driving torque setting value, and the starting operation torque is output.

 According to still another aspect of the operation control method of the present invention, when the normal driving drive is applied to the hybrid vehicle, the main control unit controls the engine to run on the optimal economic running curve through the first motor system on the one hand, and controls the driving demand according to the driving principle on the other hand. The output torque of the two motor system. In most operating situations, the first motor system power generation is all used for the second motor system drive, or the second motor system power generation is all used for the first motor system drive, unless the energy storage unit is controlled according to its own control strategy. The main control unit instructs to actively propose charging and discharging requirements, and all power generation energy does not pass through the charging and discharging process of the energy storage unit. DRAWINGS

 Figure 1 is a schematic block diagram of a prior art series power structure and energy flow.

 2 is a schematic block diagram of a prior art parallel power structure and energy flow.

 3 is a schematic block diagram of a conventional series-parallel hybrid power structure' and energy flow direction. 4 is a schematic view showing the power structure of the hybrid electric vehicle of the present invention.

 In the figure, the correspondence between components and reference numerals is as follows:

1: Engine 2: Engine output shaft 3: First speed/position sensor 4: First rotor 5: Second rotor 6: Collector ring 7: Differential 8: Reduction gear 9: Output gear 10: Output shaft 1 1 : Stator 12: Third rotor 13 Drive shaft 14: Second speed/position sensor 15: Second servo drive 16: Common DC bus. 17: Main control unit 18: First servo drive 19: Energy storage unit 20: Engine control Unit 51: differential; 52: drive shaft; 53: electric motor; 54: battery; 55: controller assembly; 56: generator; 57: engine; 58: coupling; 59: transmission and coupling specific Implementation The power structure of the hybrid electric vehicle of the present invention is implemented as follows:

 As shown in Fig. 4, the power structure of the hybrid electric vehicle includes the main parts of the engine 1, the dual motor servo, the output drive train, the engine control unit 20, the energy storage unit 19, and the main control unit 17. The dual motor servo device includes first and second two-phase permanent magnet synchronous motors, and a first servo driver 18 and a second servo driver 15. The first motor includes a first rotor 4 and a second rotor 5, and the first rotor 4 is embedded There is a permanent magnet pole, and a motor winding is mounted on the core of the second rotor 5. The shaft of the first rotor 4 is an input shaft of a dual motor and is directly connected to the output shaft 2 of the fuel engine 1. The shaft of the second rotor 5 is a dual motor output shaft 10. The second motor includes a third rotor 12 and a stator 11, the stator 11 is fixed to the casing, the third rotor 12 is embedded with a permanent magnet pole, and the stator 11 is provided with a motor winding. The second motor third rotor 12 and the first motor second rotor 5 share an output shaft 10 and are connected to the output gear 9. The output gear 9 is connected to the differential 7 via a reduction gear 8, and the differential 7 is connected to the drive shaft 13, and the drive shaft 13 is externally connected to the wheel. The first and second speed/position sensors 3 and 14 are respectively mounted on the first motor first rotor shaft 2 and the second motor third rotor shaft 10, and the first speed/position sensor 3 is connected to the first servo driver 18, The second speed/position sensor connects the first and second servo drives 18 and 15. The first servo driver 18 is electrically connected to the winding of the second rotor 5 of the first motor via the slip ring 6, and the second servo driver 15 is directly connected to the stator winding 11 of the second motor. The first servo driver 18 and the second servo driver 15 are connected via a common DC bus 16.

 The main control unit 17 connects the first and second servo drivers 18 and 15, and the first and second speed/position sensors 3 and 14 are connected to the main control unit 13. The common bus 16 is also connected to the energy storage unit 19, the energy storage unit 19 includes a capacitor, a battery and its charge and discharge control and protection circuit; the battery voltage signal of the energy storage unit 19 is connected to the main control unit; the main control unit 17 is connected to the engine control unit 20, the engine control unit 2 controls the fuel engine operation; the main control unit 17 is a computer, the main control unit stores the speed torque matching data on the fuel engine optimal efficiency curve, and also stores the accelerator pedal angle and the driving torque setting. Value relationship data, battery voltage and charge demand power relationship data, brake pedal angle and brake torque relationship data. The main control unit is externally connected to the accelerator pedal angle sensor, the brake pedal angle sensor, and various control command switches.

 In the following, the power structure, operation control method, mechanism and beneficial effects of the hybrid electric vehicle of the present invention will be described in detail according to the form of expression.

1. Energy-saving operation method: 1 Adjust the operating point according to the requirements of the optimal engine efficiency curve to improve the engine efficiency: The engine control unit 20 controls the fuel engine 1 according to the routine control. When the angle of the accelerator pedal changes, the engine 1 speed changes accordingly, and the first motor of the mechanism is first. The rotor 4 rotates synchronously, and the main control unit 17 obtains the current speed of the engine 1 from the first speed/position sensor 3, and obtains the matching torque T of the current speed according to the speed-torque relationship data of the pre-stored engine optimal efficiency running curve. And thereby providing the first servo driver 18 with the set torque, the first servo driver 18 obtaining the first and second rotors according to the torque set value and by the first speed/position sensor 3 and the second speed/position sensor 14. Relative position signal, dynamically output corresponding current vector to the winding of the second rotor 5 of the motor through the collector ring 6, and perform torque servo control on the first motor, so that the first rotor 2 of the first motor 5 is opposite to the first rotor 4 The output shaft 2 applies a corresponding torque that is opposite to the steering of the engine shaft. The engine bearing is subjected to a torque equal to the torque applied by the first motor and is not directly related to the external load. The main control unit 17 dynamically acquires the current engine 1 speed, and applies the torque to the fuel engine according to the pre-stored engine-optimal efficiency running speed-torque relationship law, so that the engine is always on the optimal efficiency running curve and outputs the same mechanical power. The least depleted fuel.

 2 Adopt kinetic energy transmission, direct transmission of full electric energy, improve the utilization of engine output kinetic energy: When the first motor second rotor 5 applies the corresponding torque to the first rotor 4 opposite to the output of the engine 1 output shaft 2, The relationship between the force and the reaction force, the second rotor 5 is also subjected to the same reaction torque as the engine shaft, and the output shaft 10 of the second rotor 5 also outputs the same amount of torque to the final load.

 When the first servo driver 18 controls the first motor to apply a torque T (Nm, Nm) to the output shaft 2 of the fuel engine 1, the rotational speed of the engine shaft is N1 (rpm, rpm), the first rotor of the first motor 4 The mechanical power obtained from the engine 1 is P1 - Τ χ ΝΙ / 9550 (kW, kW), 9550 is the unit conversion factor. When the first motor second rotor 5 applies a moment opposite to the direction of rotation of the first rotor 4 to the first rotor 4, the first rotor 4 simultaneously applies equal and opposite torques to the second rotor 5, that is, at this time The two rotors 5 are simultaneously subjected to the electromagnetic torque of T (Nm ) in the same direction as the rotation of the first rotor 4. If the rotational speed of the second rotor 5 is N2 (rpm), the mechanical power P2 of the second rotor 5 is externally outputted, P2 = T X N2/9550 (kW).

When N1 > N2, this power P2 is the mechanical power directly transmitted from the engine 1 through the electromagnetic coupling of the first rotor 4 and the second rotor 5 during the control of the mechanism, which is called the transmission work. Rate. The transmission power is 100% delivered to the final load without any attenuation. The mechanical power obtained by the first motor first rotor 4 from the engine 1 is a part of the mechanical power output by the second rotor 5, and the other part is used for power generation. The power of the first motor for generating electricity Ρ3 = Ρ1 - Ρ2 = Τχ (Nl - N2 ) / 9550 (kW), the power of the first motor for generating electricity multiplied by the overall efficiency η of the first motor and the first servo driver ΐ That is, the electric power output from the motor to the common DC bus line Ρ4, Ρ4 = η 1 Τ (Nl - Ν2) / 9550 (kW) _{0 The} main control unit 17 is based on the second servo driver 15 whose overall power is integrated with the efficiency η 2 And the principle that the second motor absorbs and converts into mechanical power, according to the currently applied engine shaft torque Τ, the current engine speed Nl, the rotation speed of the second rotor output shaft 10 is Ν2, and the combination of the first and second motors and the servo drive The efficiency η 1 , η2 obtains the set torque of the second servo driver, and the second servo driver 15 obtains the position signal of the third rotor 12 of the second motor through the second speed/position sensor 14, according to the torque set value and the third The position signal of the rotor 12 loads a corresponding current vector to the winding on the stator 11 of the second motor, servo-controls the second motor and extracts the corresponding torque. The second motor converts all the electric energy that the first motor currently feeds into the common straight bus 16 into kinetic energy and outputs from the third rotor shaft 10, and drives the reduction gear 8 and the difference through the output gear 9 together with the second rotor 5 of the first motor. Speeder 7 up to the drive shaft. The power generated by the first motor is directly supplied to the second motor, which avoids the double loss of charging and re-discharging of the battery through the energy storage unit 19, and the energy utilization is higher, which is called direct transmission of electric energy; the second motor is supplied to the output shaft 10 Mechanical power Ρ5 = Ρ4χ η 2= η 2 η 1 X Τ (Nl -Ν2 ) /9550 ( kW ), under this scheme, the total driving power obtained by the external load Po=P2+P5 = TX N2/9550+ _η 2η 1 Τχ (Nl - Ν 2 ) / 9550 ( kW ) = η 1 η2 PI + ( 1 - η 1 η2) P2. The overall efficiency of the generator and the motor is the same, and the external load is more than (1 - η 1 η 2 ) P2 power than the engine-generator-motor series power mechanism.

 When Ν1=Ν2, the power Ρ1=Ρ2, that is, the mechanical power output by the engine 1 is directly transmitted by the electromagnetic coupling of the first motor to the dual motor output shaft 10, at which time the first motor drive system only consumes the required current for maintaining the current. A small amount of electrical energy. In this state, the second motor operates in a zero power output state unless the control strategy of the master unit 17 considers it necessary, and does not consume electrical power.

When Ν1 <Ν2, the power Ρ1 <Ρ2, that is, the mechanical power outputted by the engine 1 is directly transmitted by the electromagnetic coupling of the first motor to the dual motor output shaft 10, and the first motor system also absorbs electric energy from the common DC bus 16. And converted into kinetic energy superimposed to the dual motor output shaft 10. The power of the first motor system is P1, and the power of the motor output is Ρ2-P1. The electric power taken from the DC bus 16 is (P2 - PI ) / η 1. At this time, under the control of the control strategy of the main control unit 17, there are three cases in the working state of the second motor system: First, the second motor system absorbs electric energy from the common DC bus 16 and converts it into kinetic energy from the dual motor output shaft 10 The upper output, at this time, the energy storage unit 19 sends power from the battery to the bus 16 for use by the dual motor; second, the second motor applies a torque opposite to the direction of rotation to the output shaft 10, and the kinetic energy is removed from the output shaft and converted into electrical energy. The busbar 16 is in turn used by the first motor system, at which time the energy storage unit 19 does not participate in energy access; third, the second motor system outputs zero torque, does not participate in driving or generating electricity, and at this time the energy storage unit I ^{9 is} from the battery Power is delivered to the busbar 16 for use by the first motor.

3 Recovering braking energy: When the hybrid vehicle is braking, the main control unit 17. Obtain the braking signal from the externally connected brake pedal angle sensor, and can control the first motor braking, the second motor braking or the double electric mechanism respectively. move. When the first motor brakes, - the engine 1 continues to rotate, the main control unit 17 sets a negative set torque to the first servo driver 18, and the first servo driver I ⁸ controls the first motor second rotor 5 to the first rotor 4. Applying the same torque as the engine steering, the engine is operated in a dragged state, so that the torque received on the output shaft of the second rotor 5 is opposite to the normal driving direction and enters the braking state. When the first motor brakes, the main control unit 17 must control the braking torque not to be too large to avoid the engine dead fire. Therefore, the braking state is equivalent to the engine viscous braking when the conventional automobile is in the range of the taxi. When the second motor brakes, the torque setting signal sent from the main control unit 17 to the first servo driver 18 is zero, and the first servo driver 18 controls the first motor output torque to be zero, so that the engine 1 and the dual permanent magnet synchronous motor Output shaft 10 is isolated. The main control unit 17 obtains the brake torque setting signal to the second servo driver 15 according to the brake pedal angle and the pre-stored torque demand relationship data, and the third rotor position obtained by the second servo driver 15 according to the second speed/position sensor 14. The braking torque set value provided by the signal and main control unit 17 applies a current vector to the stator 11 of the second motor for torque servo control, so that the double permanent magnet synchronous motor output shaft 10 applies braking torque to the outside. The first and second motors simultaneously brake the state, that is, simultaneously control the braking torque of both.

The braking state of the motor is in the generator state, and the kinetic energy obtained by the double permanent magnet synchronous output shaft 10 from the external load driving shaft 13 is converted into electric energy and sent to the common DC bus 16 through the servo drives; the energy storage unit 19 is The braking condition obtains electric energy from the common DC bus 16 and stores the electric energy on the internal capacitor or charges the battery according to the charging control law, thereby achieving the purpose of recovering the braking energy. When the recovered braking energy causes the common DC bus voltage to rise above a predetermined voltage value, the energy storage unit 19 activates the energy bleed passage therein, Excess electrical energy is converted to thermal energy by electrical resistance until its voltage drops to a predetermined safe value.

2. Multiple power sources are electromagnetically coupled and combined:

 In the electromagnetic direct coupling type power structure, there are three power sources of the engine 1, the first and the second servo motor. The output torque of the engine 1 is electromagnetically passed through the second rotor 5, the dual motor output shaft 10, the output gear 9, the reduction gear 8, the differential 7, the wheel drive shaft through the first motor first rotor 4 on its shaft. The torque transmitted by the engine 1 to the dual motor output shaft 10 is equal to the torque Ta applied by the first servo driver 18 to the first rotor 4 via the second rotor 5 of the first motor; the second motor acts on the dual motor output shaft The torque of 10 is equal to the electromagnetic torque Tb of the second motor stator 11 acting on the third rotor 12 of the second motor; the output torque of the output shaft of the dual motor is the output torque of the power structure To = Ta + Tb; the three power sources do not pass the gear The mechanical structure is coupled, but is electromagnetically coupled to the common output shaft to drive the car. The connection of the power structure is simpler than the series, parallel and hybrid. The main control unit 17 provides corresponding setting signals to the first and second servo drivers 18 and 15 according to external control requirements and internal control programs, so that the three power sources act on the dual motor output shaft 10 by electromagnetic force alone or in combination. The automobile is driven by the output gear 9, the reduction gear 8, the differential 7, and the drive shaft 13 on the output shaft 10 to realize starting, stable operation, short-time high-overload operation, and reverse operation.

1 Car start: At this time, the engine 1 is not started, and the first rotor 4 is stationary. The main control unit 17 obtains a start signal from the externally connected control switch and the accelerator pedal angle sensor, and the main control unit 17 supplies a zero torque setting signal to the first servo driver 18, and performs torque servo control on the first motor to make the second rotor 5 The interaction torque with the first rotor 4 is zero, so that the engine 1 is isolated from the double permanent magnet synchronous motor output shaft 10, that is, isolated from the wheel drive shaft 13; meanwhile, the main control unit 17 is based on the pre-stored accelerator pedal angle and the driving torque relationship data. The setting signal Tb of the second servo driver 15 is obtained, and the second servo driver I ⁵ draws the electric energy supplied by the energy storage unit 19 through the common DC bus 16, and is provided according to the signal of the second speed/position sensor 14 and the main control unit 17. The torque setting, the current vector is applied to the winding on the stator 11 of the second motor, the second motor is operated in the motor state, and the electric energy is converted into kinetic energy, through the double permanent magnet synchronous motor output shaft 10, the output gear 9, the reduction gear 8. The differential 7 and the drive shaft 13 drive the vehicle to run; in this state, the voltage of the battery of the energy storage unit 19 is gradually decreased; The main control unit 17 obtains the rotational speed of the output shaft 10 of the dual permanent magnet synchronous motor according to the second speed/position sensor 14, and obtains the current actual driving power according to the rotational speed and the second motor output torque Tb, according to the first and second motors. Comprehensive efficiency to obtain total drive demand The main control unit 17 also obtains the charging demand power from the battery voltage signal of the energy storage unit 19 and the pre-stored battery voltage and charging demand power relationship data; the sum of the current total driving demand power and the charging demand power is the total power of the engine Demand, when the total power demand value for the engine is greater than the pre-stored threshold, the main control unit 17 controls the engine control unit 20 to start the engine 1, and presses the 2 mode to perform steady and fixed operation.

 2 Stable operation: The engine 1 is normally operated under the control of the engine control unit 20, and the main control unit 17 controls the operation of the engine 1 in accordance with the above method.

 3 short-time high-overload operation: The main control unit 17 reads the external accelerator pedal sensor angle signal at intervals, and calculates the gradient signal of the accelerator pedal sensor angle. According to the pre-stored accelerator pedal angle and its gradient signal, it is short-term high. The torque relationship is used to obtain the second motor overload running torque, and the second servo driver 15 draws the energy provided by the first motor power generation and power unit 19 from the common bus 16 to perform torque servo control on the second motor according to the set value. Applying the torque of the short-time overload operation to the output shaft 10 of the dual-parallel permanent magnet synchronous motor, driving the vehicle together with the torque transmitted by the first motor to quickly respond to the driver's instantaneous demand for large drive torque, in the process The main control unit 17 still obtains the torque setting value of the first servo driver 18 according to the requirements of the optimal efficiency curve and the economic operation control, and operates the engine 1 on the optimal efficiency curve according to the method described in the above Article 1.

 4 Reverse running: The main control unit 17 obtains the reverse signal and the accelerator pedal angle signal according to the externally connected control switch and the accelerator pedal angle sensor, and the main control unit 17 supplies the first servo driver 18 with a zero torque setting signal, and the first servo driver 18 According to the torque servo control of the first motor, the interaction torque between the second rotor 5 and the first rotor 4 is zero, so that the engine 1 is isolated from the double permanent magnet synchronous motor output shaft 10, that is, isolated from the wheel drive shaft 13; At the same time, the torque setting signal of the second servo driver 15 is obtained according to the relationship data between the pre-stored accelerator pedal angle and the driving torque, and the second servo driver 15 controls the second motor to output the corresponding reverse torque to drive the output shaft to reversely operate. When the wheel drive shaft is reversed, the car is reversed.

5 Since the output shaft 10 of the dual motor outputs the torque To = Ta + Tb, the main control unit 17 increases the torque setting value Tb of the second servo driver according to the control, and the second servo driver 12 draws the first motor from the common bus. The energy is sent, and the energy is driven from the energy storage unit 19 to drive the second motor to apply more torque to the double permanent magnet synchronous motor, so that the output torque To of the dual permanent magnet synchronous motor can be greater than the output torque of the coupled engine; The motor has several times of short-term overload operation capability, and the main control unit has short-term control requirements and overload capability. The allowable value increases the torque setting value Tb of the second servo drive. The short-term value of To can be much larger than the maximum output torque of the engine. The two-motor output torque variation gradient motor depends on the current vector variation gradient, which can usually rise from zero in milliseconds. To the rated value, the output torque rise gradient of the two motors is much larger than that of the engine. With the solution of the present invention, when equipped with a dual motor with a total power equivalent to the engine capacity, the dual motor output shaft can obtain a larger short-time torque and a faster torque rise gradient than the engine, and the overall vehicle has better power performance. If only the same power is required, the power unit of the present invention is used, and there is a possibility of adapting a small displacement engine and a small capacity dual motor to improve economy.

 3, torque and speed:

The engine control unit 20 changes the engine 1 speed following the externally connected accelerator pedal in a conventional control manner, and the main control unit 17 obtains the current engine speed from the first speed/position sensor 3, and the running speed of the pre-stored engine optimum efficiency curve - The torque relationship data finds the matching torque of the current speed, and thereby provides the set torque to the first servo driver 18, according to which the first servo driver 18 passes the first speed/position sensor 3 and the second speed/ The position sensor 14 obtains the relative position signals of the first and second rotors, dynamically outputs corresponding current vectors to the windings of the second rotor 5 of the motor through the collector ring 6, and performs torque servo control on the motor to make the first rotor 2 of the first motor 5 A corresponding torque opposite to the steering of the engine shaft is applied to the first rotor 4, i.e., the shaft 2 of the engine 1. The engine shaft 2 is subjected to a torque equal to the torque applied by the first motor and is not directly related to the external load. The main control unit 17 dynamically acquires the current engine 1 speed, and applies the torque to the fuel engine according to the pre-stored engine-optimal efficiency running speed-torque relationship law, so that the engine 1 is always on the optimal efficiency running curve and outputs the same machine. The fuel with the least power loss. At this time, the first motor second rotor 5 directly supplies the same amount of torque to the dual motor output shaft 10, through the output gear 9, the reduction gear 8, the differential 7, and the wheel drive shaft 13 to drive the vehicle to operate. At the same time, the first motor converts excess kinetic energy from the engine 1 into electrical energy for delivery to the DC bus. The main control unit 17 calculates the first motor power generation to the common bus 16 according to the engine speed, the first motor second rotor 5 speed, the torque applied to the engine by the first motor, and the integrated power generation efficiency of the first motor and the first servo driver 18. The electric power is determined according to the principle that the sum of the electric power of the second motor and the energy storage unit 19 is equal to the power generated by the first motor, or the charging power assigned to the energy storage unit 19. The second servo driver 15 obtains the position signal of the third rotor 12 of the second motor through the second speed/position sensor 14, according to the twist given by the main control unit 17 The moment set value and the position signal of the second rotor 12 of the second motor perform torque servo control on the second motor, and the output shaft 10 is loaded with a corresponding torque. The second servo driver 15 extracts energy from the common busbar into mechanical energy via the second motor, and passes through the dual motor output shaft 10, the output gear 9, the reduction gear 8, and the differential 7 together with the power transmitted by the engine 1 through the first motor. The wheel drive shaft 13 drives the vehicle to operate. When the relative magnitude of the combined torque and the running resistance of the dual motor output changes, the driving torque of the two motors is controlled by the servo drive servo, independent of the speed, thereby achieving the purpose of automatic shifting; when the main control unit 17 is driven by the driving demand and the engine 1 The need for optimum efficiency operation changes the torque setting of the dual motor system, the servo drive achieves the purpose of torque change of the device.

 4. Simplify the power structure

 The common axis of the first and second motors is the output shaft 10 of the double permanent magnet motor, and the three power sources of the engine 1, the first and the second motor are electromagnetically coupled to the output shaft 10 of the double permanent magnet motor, simplifying The mechanical connection between the power sources; the output shaft 2 of the engine is not directly mechanically coupled with the output shaft 10 of the dual motor, the differential 7 and the drive shaft 13, and the power of the engine 1 is passed through the first rotor 4 of the first motor. The two rotors 5 are coupled to the output shaft 10 of the dual motor, and the main control unit 17 supplies the set torque to the first servo driver 18 according to the electromagnetic torque variation rule of the isolation and engagement process, and controls the first motor to apply correspondingly to the engine shaft 2. Torque, the engine shaft 2 and the dual motor shaft 10 can be isolated or regularly engaged, thus replacing the conventional clutch; the main control unit 17 can widen the double permanent magnet synchronous motor through the first and second servo drives 18, 15 Rapid adjustment of torque and wide speed range, replacing the traditional stepped or continuously variable transmission, this power structure reduces the clutch, the transmission planet Moving parts such as gears reduce the clutch and transmission control mechanism, greatly simplifying the power structure.

Claims

Rights request A power structure of a hybrid electric vehicle, comprising: an engine, a motor unit composed of a first motor and a second motor, an output gear, a reduction gear, and a differential, wherein the first motor includes electromagnetic coupling with each other a rotor and a second rotor, the second motor including a stator and a third rotor electromagnetically coupled to each other, the shaft of the first rotor being an input shaft of the cascade motor assembly, and the shaft of the second rotor being coaxial with the third rotor and acting An output shaft of the cascade motor assembly, a shaft of the first rotor is directly connected to an output shaft of the engine, and an output gear is mounted on the output shaft between the first and second motors, the output gear is driven by a reduction gear and a differential speed Connected to the drive shaft that connects the wheels, characterized by:  The power structure of the hybrid electric vehicle further includes a main control unit, a first servo drive associated with the first motor, and a second servo drive associated with the second motor, the first servo drive being operated according to the operation Servo control of the coupling torque between the first rotor and the second rotor; the second servo drive servo-controls the coupling torque between the stator and the third rotor according to the operation condition; the main control unit is used for pressing according to the engine speed The pre-stored optimal economic operating curve calculates a corresponding matching torque, sends a corresponding torque setting to the first servo drive, and sends a torque setting to the second servo drive according to the running condition or driving requirement of the vehicle.  2. The power structure of a hybrid electric vehicle according to claim 1, further comprising: an engine control unit that can receive a signal from the main control unit to perform speed control or start/stop control on the engine.  3. The power structure of a hybrid electric vehicle according to claim 1, wherein: a first speed/position sensor is mounted on a shaft of the first rotor, and the first speed/position sensor is connected to the first servo a second speed/position sensor mounted on a common axis of the second rotor and the third rotor, the second speed/position sensor connecting the first and second servo drivers, the first servo driver responding to the torque setting and The feedback signals of the first and second speed/position sensors servo-control the coupling torque between the first rotor and the second rotor to achieve independent adjustment of the engine operating point independently of the vehicle operating state; the second servo driver The coupling torque between the stator and the third rotor is servo-controlled in response to the torque setting and the feedback signal of the second speed/position sensor to drive the second motor to the entire vehicle. 4. The power structure of a hybrid electric vehicle according to claim 1, characterized in that Wherein: the first motor is a permanent magnet synchronous motor, wherein a permanent magnet pole is mounted on one of the first rotor and the second rotor, and the other of the first rotor and the first rotor is mounted a first winding wound on the iron core; the second motor is a permanent magnet synchronous motor, wherein a permanent magnet pole is mounted on one of the third rotor and the stator, and the third rotor and the stator are The other of the two is mounted with a second winding wound on the core.  5. The power structure of a hybrid electric vehicle according to claim 4, wherein: the first winding is connected to the first servo driver through a slip ring mounted on the shaft thereof, to obtain the first a control current of the servo drive; the second winding is arranged in one of the following cases: the winding is arranged on the stator and directly connected to the second servo drive; the winding is arranged on the third rotor and mounted on the output shaft The slip ring is connected to the second servo driver.  6. The power structure of a hybrid electric vehicle according to claim 4, wherein: the first and second motors are respectively a permanent magnet synchronous motor or a brushless DC motor.  7. The power structure of a hybrid electric vehicle according to claim 1, wherein: the first servo driver and the second servo driver are connected by a common DC bus, and the common DC bus is further connected to the energy storage unit for The control unit requires itself and its own charge and discharge strategy to obtain electrical energy from the DC bus and store it in or from it to the DC bus.  8. The power structure of a hybrid electric vehicle according to claim 7, wherein: said energy storage unit comprises a capacitor, a battery, and a charging control and protection circuit thereof.  9. The power structure of a hybrid electric vehicle according to claim 1, wherein: the main control unit is a computer.  10. The power structure of a hybrid electric vehicle according to claim 9, wherein: the main control unit further stores relationship data between an accelerator pedal opening degree and a driving torque setting value, an energy storage unit voltage, and a charging requirement. The power relationship data, the brake pedal opening degree and the braking torque relationship data, the shift control program, the main control unit externally connected to the accelerator pedal opening degree sensor, the brake pedal angle sensor, and various control command switches. 11. The power structure of a hybrid electric vehicle according to claim 10, wherein: the control unit controls the first servo driver and/or the second servo driver according to at least one of the following data stored therein, and further Controlling the operation of the first motor and/or the second motor: Speed-torque matching data on the engine's best efficiency curve;  The upper and lower power limits of the economic operating zone of the optimal efficiency curve;  Data relating to the accelerator pedal angle and the driving torque setting value;  Data relating to energy storage unit voltage and charging demand power;  Brake pedal angle and brake torque relationship data;  Variable speed control program.  12. The power structure of a hybrid electric vehicle according to claim 10, wherein: when the hybrid vehicle is started, the main control unit controls the first servo drive to make the first rotor and the first motor of the first motor The interaction torque between the two rotors is zero, and the second motor is torque-controlled by the second servo driver according to the relationship between the accelerator pedal angle and the driving torque setting value, and the starting operation torque is output.  13. The power structure of a hybrid electric vehicle according to claim 10, wherein: after starting, when the sum of the driving power demand and the charging power demand of the energy storage unit is greater than a preset threshold, the engine control is notified. The unit starts the engine running.  14. The power structure of a hybrid electric vehicle according to claim 10, wherein: when a normal driving drive is applied to the hybrid vehicle, the main control unit controls the engine to operate at an optimal economy through the first motor system. On the running curve, on the one hand, the output torque of the second motor system is controlled according to the driving demand. In most operating situations, the first motor system power generation is all used for the second motor system drive, or the second motor system power generation is all used for the first motor system drive, unless the energy storage unit is controlled according to its own control strategy. The main control unit instructs to actively propose charging and discharging requirements, and all power generation energy does not pass through the charging and discharging process of the energy storage unit.  15. The power structure of a hybrid electric vehicle according to claim 10, wherein: when braking the hybrid vehicle, the main control unit controls the hybrid vehicle according to the same load torque of the brake pedal angle. Limited dynamic braking; and  The second motor is controlled to output the braking torque to the outside by the second servo driver according to the brake pedal angle and the braking torque.  16. The power structure of a hybrid electric vehicle according to claim 10, wherein: during braking, external load kinetic energy is converted into electric energy by the first motor system or the second motor system and the electric energy is transmitted to the DC bus. . 17. The power structure of a hybrid electric vehicle according to claim 16, wherein The sign is: When braking, the energy storage unit actively takes electrical energy from the common DC bus to store it. 18. The power structure of an electric hybrid electric vehicle according to claim 17, wherein: if the power of the recovered electric energy is too large during braking, the charging process of the energy storage unit is too late to absorb the energy, thereby causing the DC bus voltage to rise. To a predetermined value; or if the energy is too much, the energy storage unit is insufficient to store the energy, and the DC bus voltage rises to a predetermined value, the energy bleed protection device inside the energy storage unit starts to bleed, and the excess energy is passed through the braking resistor. The conversion to heat is consumed.  19. The power structure of a hybrid electric vehicle according to claim 10, wherein: when reversing, the main control unit controls the first servo drive according to a reverse running demand and an accelerator pedal angle to make the first motor first. The interaction torque between the rotor and the second rotor is zero; and the second motor outputs the reverse driving torque through the second servo driver according to the accelerator pedal angle and the driving torque set value relationship.  20. The power structure of a hybrid electric vehicle according to claim 10, wherein: when a relative change occurs between a total output torque of the output shaft of the dual motor and a load torque of the vehicle, the vehicle speed automatically changes steplessly. The total output torque is only controlled by the main control unit and each servo drive and is not directly related to the vehicle speed.  21. The power structure of a hybrid electric vehicle according to claim 10, wherein: when the driver changes the accelerator pedal angle, the engine speed changes accordingly, and the first motor transmission torque also changes accordingly, and the main control unit The second motor system is controlled to output a corresponding torque to achieve stepless adjustment of the output torque.  22. The power structure of a hybrid electric vehicle according to claim 20, wherein: the main control unit controls the second motor according to a speed change of the angle and angle of the accelerator pedal and a short-time overload capability of the second motor system. The system outputs short-time overload torque to improve the vehicle's dynamic performance and operational sensitivity. 23. An operation control method for a power structure of a hybrid electric vehicle, wherein the power structure of the hybrid electric vehicle comprises: an engine, a motor group composed of a first motor and a second motor, an output gear, and a deceleration a gear and a differential, wherein the first electric machine includes a first rotor and a second rotor electromagnetically coupled to each other, the second electric machine including a stator and a third rotor electromagnetically coupled to each other, the shaft of the first rotor being the cascading motor assembly An input shaft, a shaft of the second rotor being coaxial with the third rotor and serving as an output shaft of the cascade motor assembly, the shaft of the first rotor being directly connected to the output shaft of the engine, and the output between the first and second motors An output gear is mounted on the shaft, and the output gear is connected to the differential via a reduction gear, and the differential a drive shaft connecting the wheels, the power structure of the hybrid electric vehicle further comprising a main control unit, a first servo drive associated with the first motor, and a second servo drive associated with the second motor, The operation control method includes the following steps:  The main control unit calculates a corresponding matching torque according to the pre-stored optimal economic running curve of the engine according to the engine speed, sends a corresponding torque setting to the first servo driver, and sends a torque to the second servo driver according to the running condition or driving requirement of the vehicle. set up;  The first servo driver servo-controls a coupling torque between the first rotor and the second rotor according to an operation condition, and the second servo driver servo-controls a coupling torque between the stator and the third rotor according to an operation condition.  24. The operation control method of a power structure of a hybrid electric vehicle according to claim 23, wherein the step of servo-controlling the coupling torque between the first rotor and the second rotor comprises the following steps: The first servo driver acquires the absolute position signal θ ρ of the first rotor from the first speed/position sensor, and acquires the absolute position signal θ _{2 of the} second rotor from the second speed/position sensor to obtain the first rotor relative to the second rotor Position angle ( - θ ₂ );  Obtaining the direction of the current vector of the first winding according to the principle that the current vector and the back EMF vector are in phase; Reading the torque set value from the control unit, calculating the magnitude of the current vector; obtaining the instantaneous setpoints i _al , i _bl , i _{cl of the} three-phase current;  Perform three-phase current closed-loop control separately;  Drive the power amplifier circuit.  The operation control method for a power structure of a hybrid electric vehicle according to claim 23, wherein the step of servo-controlling the coupling torque between the stator and the third rotor comprises the following steps: The second servo driver acquires the absolute position signal θ _{2 of the} third rotor from the second speed/position sensor;  Obtaining the direction of the second winding current vector according to the principle that the current vector and the back EMF vector are in phase; Reading the torque set value from the control unit, calculating the magnitude of the current vector; obtaining the instantaneous setpoints i _a2 , i _b2 , i _{c2 of the} three-phase current;  Perform three-phase current closed-loop control separately; Drive the power amplifier circuit. 26. The operation control method for a power structure of a hybrid electric vehicle according to claim 23, wherein: the main control unit body is a computer, and an accelerator pedal opening degree and a driving torque setting value are also stored therein. Relational data, energy storage unit voltage and charging demand power relationship data, and brake pedal opening degree and braking torque relationship data, shift control program, external control unit externally connected accelerator pedal opening degree sensor, brake pedal angle sensor, each a control command switch; the control unit controls the first servo driver and/or the second servo driver according to at least one of the following data stored therein, thereby controlling the operation of the first motor and/or the second motor:  Speed-torque matching data on the engine's best efficiency curve;  The upper and lower power limits of the economic operating zone for the best efficiency curve; ― data on the relationship between the accelerator pedal angle and the drive torque setpoint;  Data relating to energy storage unit voltage and charging demand power;  Brake pedal angle and brake torque relationship data;  Variable speed control program.  27. The control method of a power structure according to claim 26, wherein: the step of servo-controlling a coupling torque between the first rotor and the second rotor comprises: when a startup is performed on the hybrid vehicle, The main control unit controls the first servo driver such that the interaction torque between the first rotor and the second rotor of the first motor is zero;  The step of servo-controlling the coupling torque between the stator and the third rotor includes: torque-controlling the second motor by the second servo driver according to the relationship between the accelerator pedal angle and the driving torque setting value, and outputting the starting operating torque.  28. The control method of a power structure according to claim 26, wherein: after starting, when the sum of the driving power demand and the energy storage unit charging power demand is greater than a preset threshold, notifying the engine control unit to start the engine run. 29. The control method of a power structure according to claim 26, wherein: when the hybrid vehicle is driven by the normal driving, the main control unit controls the engine to run on the optimal economic running curve through the first motor system. On the one hand, the output torque of the second motor system is controlled according to the driving demand. In most operating situations, the first motor system power generation is all used for the second motor system drive, or the second motor system power generation is all used for the first motor system drive, unless the energy storage unit is controlled according to its own control strategy. The main control unit instructs to actively propose charging and discharging requirements, and all power generation energy does not pass through the charging and discharging process of the energy storage unit. 30. The control method of a power structure according to claim 26, wherein: when braking the hybrid vehicle, the main control unit controls the hybrid load vehicle according to the brake pedal angle to control the hybrid vehicle. Braking; and  The second motor is controlled to output the braking torque to the outside by the second servo driver according to the brake pedal angle and the braking torque.  31. A method of controlling a power structure according to claim 26, wherein: during braking, the external load kinetic energy is converted to electrical energy by the first motor system or the second motor system and the electrical energy is delivered to the DC bus.  32. The control method of a power structure according to claim 31, wherein: when braking, the energy storage unit actively acquires electric energy from the common DC bus to be stored therein. 33. The method of controlling a power structure according to claim 32, wherein: if the power of the recovered electrical energy is too large during braking, the charging process of the energy storage unit is too late to absorb the energy, causing the DC bus voltage to rise to a predetermined value; Or if the energy is too much, and the energy storage unit is insufficient to store the energy, the DC bus voltage rises to a predetermined value, and the energy bleed protection device inside the energy storage unit starts to bleed, and the excess energy is converted into heat energy consumption through the braking resistor. Drop it.  The control method of the power structure according to claim 26, wherein: when reversing, the main control unit controls the first servo driver according to the reverse running demand and the accelerator pedal angle, so that the first rotor and the first motor of the first motor The interaction torque between the two rotors is zero, and the second motor outputs the reverse driving torque through the second servo driver according to the accelerator pedal angle and the driving torque set value relationship.  35. The control method of a power structure according to claim 26, wherein: when a total output torque of the dual motor output shaft and a load torque of the vehicle are relatively changed, the vehicle speed is automatically steplessly changed, and the total output torque is only Controlled by the main control unit and each servo drive, it is not directly related to the vehicle speed.  36. The method of controlling a power structure according to claim 26, wherein: when the driver changes the accelerator pedal angle, the engine speed changes correspondingly, the first motor transmission torque also changes accordingly, and the main control unit controls the second motor. The system outputs the corresponding torque, thereby enabling stepless adjustment of the output torque. 37. The control method of a power structure according to claim 36, wherein: the main control unit changes speed according to an angle and an angle of the accelerator pedal, and can be based on the second power The short-time overload capability of the machine system controls the second motor system to output short-time overload torque to improve the dynamic performance and operational sensitivity of the vehicle.