JP2013203117A - Electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve an optimal fuel consumption rate as a whole by maximizing the efficiency of an engine, a generator, and a motor of a series hybrid electric vehicle.SOLUTION: A series hybrid electric vehicle includes an engine 5, an AC generator 6 driven by the engine 5, a flow rectifier 7, a variable frequency inverter 3, a three-phase induction motor 1, a wheel 10, and a control device for controlling the engine 5, the AC generator 6, the variable frequency inverter 3, and the three-phase induction motor 1. A generation control means 8 of the control device performs control to drive the engine 5 and the AC generator 6 with maximum efficiency during constant speed traveling other than a time of changing a rotational speed. An induction motor control means 9 of the control device performs control so as to drive, in a region of a rotational speed where efficiency is highest, the three-phase induction motor 1 with optimum slipping, to drive the three-phase induction motor with the slipping of the largest torque in a region of a rotational speed where large torque is necessary, and to drive the three-phase induction motor with intermediate slipping in a region of an intermediate rotational speed.

Description

  The present invention relates to an electric vehicle, and more particularly to an electric vehicle with a range extender.

  Conventionally, an electric vehicle has a short cruising distance because it uses a battery as a power source. This is one of the reasons why the spread of electric vehicles is delayed. Therefore, an engine is installed to form a hybrid electric vehicle. Of these, an engine, a generator, a battery, and a motor connected in series are called a series hybrid electric vehicle or an electric vehicle with a range extender. The power generation system installed is the “range extender”. The entire vehicle is referred to as a “range extended electric vehicle” or a “range extender type electric vehicle”. The range extender means a cruising range extension device, which is an electric vehicle equipped with a power generation engine.

  The range extender generally uses an internal combustion engine and a generator. When the remaining amount charged in the secondary battery decreases, the cruising distance is secured by turning the generator with the engine and supplying the generated electric power to the drive motor for running. The engine of the range extender has a smaller displacement than the vehicle size. The small displacement engine is used for the purpose of reducing mechanical loss and improving efficiency in the normal range. Even when the initially charged electricity is used up, it is possible to continue running by charging during steady running. When strong acceleration is required, the battery power is fully utilized to achieve acceleration that is commensurate with the vehicle's character.

  Since it is basically an electric vehicle, a large-capacity battery such as lithium ion is installed. Since the engine is exclusively for power generation, it tends to be mounted with a small one for the car grade. Since this system configuration does not have a clear classification standard, it is also called an electric vehicle or a series (plug-in) hybrid. The system configuration is exactly the same as the series hybrid, but there is no internationally consensus classification standard. Since this type of electric vehicle can drive the engine with high efficiency, the fuel consumption rate is good. Some devices are designed to further increase efficiency by optimally controlling torque and rotation speed.

  Since series hybrid electric vehicles do not require a battery, some vehicles do not have a battery. However, since the regenerative power cannot be stored as it is, the efficiency is not good. Therefore, there is one that uses a different mechanism to take in energy and assist during acceleration without once converting to electricity during deceleration. It is a mechanism that mechanically uses energy during braking as energy during acceleration using liquid and gas. Already in commercial trucks. Use a low-pressure liquid container and a high-pressure nitrogen gas container. The pump is turned during braking to inject liquid into the high pressure gas side. The gas is compressed to a high pressure state. At the time of acceleration, the high pressure gas pushes back the liquid to assist the rotation of the tire.

  Some use a flywheel. Unlike ordinary hybrid vehicles that use batteries, flywheel generators supply power to the motor. This flywheel generator is a combination of a flywheel (a spinning disk flywheel), a motor / generator, and an electric control circuit. Rotates at a maximum speed of 40000rpm and stores kinetic energy. During braking, the two motors on the front axle act as generators, rotate the flywheel generator and store energy. The stored energy is used when exiting or overtaking corners that require powerful acceleration. The flywheel enters the generator mode and is electromechanically decelerated to convert kinetic energy into electricity, providing up to 120kW of power to the two front wheel motors. This power boost can be used for about 6-8 seconds, depending on the driving conditions. This is a system that converts kinetic energy that has been wasted as frictional heat of the brake into electrical energy that boosts driving power with high efficiency. This hybrid system not only provides greater power, but also improves fuel efficiency. The following are examples of prior art related to series hybrid electric vehicles.

  The “electric propulsion type mobile power supply vehicle” disclosed in Patent Document 1 is a vehicle that is reduced in weight and improved in device use efficiency. As shown to Fig.6 (a), the electric power generating apparatus mounted in a mobile power source vehicle is comprised from the diesel electric power generating apparatus and the three-phase balance apparatus. The diesel power generator includes an electronic governor, a power generation engine, and a generator. The three-phase balancing device is composed of an inverter circuit, a control circuit, and a filter. An inverter device of a vehicle drive control device is connected in parallel to the inverter circuit. The inverter device is controlled by a control circuit, and the drive motor is driven by the obtained AC output.

  The “control device for an engine-driven generator for an electric vehicle” disclosed in Patent Document 2 creates an operating environment suitable for the feeling of the driver. As shown in FIG. 6B, the ECU recognizes the vehicle speed based on the number of rotations of the motor. Depending on the vehicle speed, the generator controller changes the chopping frequency of the field current supplied to the field coil. Thus, noise corresponding to the vehicle speed can be generated without adversely affecting the efficiency of power generation. Further, the engine speed can be changed according to the vehicle speed. In this case, the engine speed is changed within a high efficiency region where the power generation efficiency of the engine hardly changes. For this reason, the power generation is not adversely affected, and the noise can be changed according to the vehicle speed.

  The “driving device for an automobile” disclosed in Patent Document 3 is an apparatus that drives an automobile by an electric motor fed from a generator driven by an internal combustion engine. As shown in FIG. 6C, the output, torque, and rotation speed of the internal combustion engine are controlled by the adjustment drive device. The generator is connected to the output shaft of the internal combustion engine. The electric motor is powered by the generator and drives the automobile. The electronic control unit controls the adjustment driving device, and controls the electric power generated by the generator and the electric power received by the electric motor depending on the adjustment position of the accelerator pedal. Moreover, the actual value rotation speed of the internal combustion engine and the generator connected thereto is detected by an electronic control unit. Furthermore, the actual value power generated by the generator and the actual value power received by the motor are detected by the electronic control unit. The electronic control device includes a rotation speed closed loop control circuit that holds the time average value of the actual value rotation speed at the predetermined target value rotation speed, and a power closed loop controller that holds the time average value of the actual value power at the predetermined target value power. It is connected. In the electronic control unit, a data memory storing characteristic curve group data for a combination of data for target value power and data for target value rotation speed, and data for adjustment of the adjustment drive unit Is assigned. The electronic control unit detects the crankshaft angle position as a variable for torque change depending on the current of the generator during power generation and driving, and diagnoses an operation failure and a motor state depending on the torque change.

  The “power supply circuit for a hybrid vehicle” disclosed in Patent Document 4 drives the engine near the maximum efficiency point to lower exhaust gas and prevent deterioration of the battery. As shown in FIG. 6D, the control unit detects the traveling stop state of the vehicle from the vehicle speed signal and the shift position signal supplied from the sensor unit. At this time, if the battery charge amount is equal to or less than a predetermined value, the engine is driven near the maximum efficiency point, power is generated by the power generation device, and the capacitor is charged until it reaches a predetermined charge value (almost fully charged). When the capacitor is charged to a predetermined charge value or more, or when the travel stop state ends, the control unit stops driving the engine. Next, the control unit connects the switch to charge the battery from the capacitor. When charging is completed, the control unit returns the switch to the original state.

  The “hybrid vehicle” disclosed in Patent Document 5 is small and low-cost. As shown in FIG. 7A, as soon as the driver presses the accelerator pedal, the power supplied to the drive motor increases. The current flowing through the drive motor never exceeds the current value when the drive motor rotates at the maximum output maximum speed. The automobile is driven by an electric motor. The generator is driven by a gasoline engine. The adjustment circuit adjusts the rotation speed of the gasoline engine and the electric power supplied to the electric motor as a function of the position of the accelerator pedal. When the accelerator pedal is depressed to increase the speed of the automobile, the electric power increases simultaneously with the rotation speed of the gasoline engine.

  The “vehicle drive device” disclosed in Patent Document 6 has good operability and good fuel consumption. As shown in FIG. 7B, the generator is driven by the internal combustion engine. The output power of the generator is distributed to two systems, each power is supplied to the motor via the power converter, and the starting wheel is driven by the motor. And according to the depression amount of an accelerator pedal, while controlling the output of a generator by a control part, the conversion electric power by a power converter is controlled.

  The “series hybrid vehicle that can be operated without a battery” disclosed in Patent Document 7 has good accelerator control response even without a battery. As shown in FIG. 7C, the AC generator is driven by the engine. An electric drive motor is connected to the alternator via an inverter for operation at a desired torque. When the driver operates the accelerator control device, the actuator operates the engine. When the maximum torque is reached, the controller controls the position of the actuator. Torque is continuously calculated from the vehicle speed, engine speed and engine output to control the vehicle propulsion torque.

  The “engine generator-equipped electric vehicle” disclosed in Patent Document 8 is equipped with an engine generator that can be used as an AC power supply, and can be charged to greatly extend the travel distance. As shown to Fig.8 (a), it drives by driving a motor with the electric power of a storage battery. Three-phase AC electricity is generated by a primary generator using an engine mounted on an electric vehicle. A control device connected to the primary generator converts the output voltage and frequency to the same current as the commercial AC current. AC current is supplied to the work equipment from a socket connected to the control device. A three-phase transformer tapped to the charging voltage is connected to the primary generator, and the direct current rectified by the three-phase full-wave rectifier is supplied to the storage battery.

  The “series hybrid vehicle control device” disclosed in Patent Document 9 can control the amount of power generation to be constant. As shown in FIG. 8B, the generator is driven by the internal combustion engine (power generation engine). The battery for driving is charged by the output of the generator. The wheels are driven by a motor for running that is powered by a battery. The hybrid control means controls the generator and motor. The internal combustion engine is controlled by the engine control means. When the generator is driven based on the accelerator opening, the hybrid control means outputs a required rotational speed for making the rotational speed of the internal combustion engine constant to the engine control means.

  The “powertrain control method for a hybrid electric vehicle” disclosed in Patent Document 10 is a method for improving the powertrain efficiency, reducing the pumping loss of the engine, and reducing fuel consumption. As shown in FIG. 8C, the first rotating electrical machine is directly driven by the engine to generate electric power. The wheel is driven by the second rotating electrical machine to which the electric power is supplied. The engine torque and the number of revolutions are controlled according to the change in the amount of power generation required for the first rotating electrical machine. Maintain the engine intake manifold pressure substantially unchanged. Overall efficiency can be improved by control that takes into account not only the operating efficiency of the engine but also the operating efficiency of the first rotating electrical machine. If the intake manifold pressure is maintained at approximately atmospheric pressure, intake loss is substantially eliminated.

  The “method for operating a series hybrid vehicle” disclosed in Patent Document 11 is a method for maximizing engine efficiency. As shown in FIG. 8D, when the driver of the series hybrid vehicle makes an output request, the second power source is the second energy stored in the energy storage device, the direct input generated by the engine. Either energy or both are supplied. It depends on the combination of the available second energy amount stored only in the vehicle's second storage device and the vehicle speed. While the engine is used to generate the second energy, the power efficiency level at which the engine operates is also the vehicle speed, the second amount of available energy stored only in the vehicle's second storage device, And depending on the combination with vehicle speed.

  The “series hybrid vehicle control device” disclosed in Patent Document 12 appropriately controls the output of the battery in accordance with the DC bus voltage. As shown in FIG. 9A, a DC bus voltage command value for the DC bus is set based on the target output of the battery and the charging rate of the battery, and the output from the battery to the DC bus is set so as to reach the battery target output. Control. When the output from the battery to the DC bus reaches the battery target output, the electric energy from the generator is controlled so that the DC voltage level of the converter approaches the DC bus voltage command value.

  The “railway vehicle drive device” disclosed in Patent Document 13 is a series hybrid railroad vehicle drive device that maintains a power generation state at an output point and a rotational speed at which the engine has a maximum operating efficiency. As shown in FIG. 9B, an engine, a generator, a converter device, a system overall control unit, an engine control unit, a constant power controller, and a PMW control unit are provided. The controller outputs the fuel injection amount command from the engine output command from the overall control unit to control the engine. The PMW controller provides a gate signal of a switching element that generates a load amount of the generator based on a command of the load amount of the generator from the overall control unit. The output characteristic with respect to the engine rotational speed is a characteristic that the output is decreased when the engine speed is increased above a specific rotational speed, and the output is increased when the engine speed is decreased. The output command to the converter device performs constant power generation control in which the load amount of the generator is a constant load amount regardless of the rotation speed.

  The “series hybrid vehicle control device” disclosed in Patent Document 14 improves drive feeling so as not to give a sense of incongruity to the occupant at the time of gear shifting in the stepped gear shifting state. As shown in FIG. 9C, a shift control line Z indicated by a broken line in which the engine speed changes at a stroke is set between the current engine operating point "X" and the target point "Y". To do. The load torque of the generator is controlled so as to trace this shift control line Z. The generator and the engine are controlled so that the engine speed changes more quickly than when the high-efficiency line L ′ is traced.

  The “vehicle control device” disclosed in Patent Document 15 can maintain the fuel consumption rate to a minimum while realizing the required generated power even if the efficiency characteristics of the engine change. Necessary fluctuations can be suppressed, the control accuracy of the peripheral control can be improved, and the overall efficiency of the power generation control can be improved. As shown in FIG. 9D, the series hybrid vehicle controls the engine torque and the generator rotational speed so as to achieve the target power generation power. The operating point feedforward setting unit calculates an engine torque and a target generator speed for achieving the target power generation power. The generated power feedback compensation unit feedback corrects the target generated power so that the actual generated power matches the target generated power. The fuel consumption rate minimizing feedback compensation unit feedback corrects the temporarily set operating point so that the fuel consumption rate, which is the ratio between the engine fuel injection amount and the actual power generation power, is minimized.

Japanese Patent Laid-Open No. 06-269102 Japanese Patent Laid-Open No. 06-296400 Japanese National Publication No. 06-511134 Japanese Unexamined Patent Publication No. 07-023504 Japanese Unexamined Patent Publication No. 07-298408 Japanese Patent Laid-Open No. 10-051905 JP 2002-369312 A JP 2004-208435 JP JP 2006-132391 A JP 2008-087758 A JP 2011-025923 JP 2011-168226 A JP 2007-195334 A JP 2008-207570 A JP 2010-173388 A

  However, the conventional series hybrid electric vehicle has the following problems. The operating efficiency of the engine and generator is taken into consideration, but the overall efficiency is not necessarily high because the efficiency of the motor is only considered in the same way as other electric vehicles.

  An object of the present invention is to solve the above-described conventional problems and maximize the efficiency of the engine, the generator, and the motor to achieve an optimum fuel consumption rate as a whole.

  In order to solve the above problems, the present invention includes an engine, an AC generator driven by the engine, a rectifier connected to the AC generator, a variable frequency inverter connected to the rectifier, and a variable frequency inverter. A series hybrid electric vehicle comprising a connected three-phase induction motor, wheels driven by the three-phase induction motor, a controller for controlling the engine, an AC generator, a variable frequency inverter, and the three-phase induction motor. The control device has a power generation control means for controlling the engine and the AC generator to operate at maximum efficiency during constant speed operation other than when the rotation speed is changed, and a rotation speed region in which the efficiency of the three-phase induction motor is maximized. Drive at the optimum slip, drive at the maximum torque in the region where the rotational speed requires a large torque, and drive at the intermediate slip in the intermediate region And configured to include an induction motor control means for controlling the so that.

  By configuring as described above, it is possible to drive the induction motor with the maximum efficiency in most of the time, and to obtain an effect that it can be operated with good operability during acceleration and deceleration.

It is a functional block diagram of the series hybrid electric vehicle in the Example of this invention. It is the figure which showed the torque and efficiency of the induction motor of the series hybrid type electric vehicle in the Example of this invention corresponding to the slip, and the correspondence figure of the voltage and slip of the induction motor. It is a functional block diagram of the induction motor control means of the series hybrid electric vehicle in the Example of this invention. It is a functional block diagram of the modification of the series hybrid type electric vehicle in the Example of this invention. It is the figure which matched the torque and efficiency of the induction motor of the modification of the series hybrid type electric vehicle in the Example of this invention corresponding to a slip, the corresponding | compatible figure of the voltage and slip of an induction motor, and a state transition diagram. It is a conceptual diagram of the conventional series hybrid type electric vehicle. It is a conceptual diagram of the conventional series hybrid type electric vehicle. It is a conceptual diagram of the conventional series hybrid type electric vehicle. It is a conceptual diagram of the conventional series hybrid type electric vehicle.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to FIGS.

  In the embodiment of the present invention, the optimum slip is driven in the region of the rotational speed where the efficiency is maximum, the slip is driven in the region of the rotational speed where a large torque is required, and the intermediate torque is driven in the region of the intermediate rotational speed. This is a series hybrid electric vehicle that controls the induction motor to drive by sliding.

  FIG. 1 shows a functional block diagram of a series hybrid electric vehicle. FIG. 2 shows the relationship between the torque and efficiency for the slip of the induction motor, and the relationship between the voltage and the slip of the induction motor. FIG. 3 shows the configuration of the induction motor control means. FIG. 4 shows a functional block diagram of a modification of the series hybrid electric vehicle. FIG. 5 shows a state transition diagram of a modification of the series hybrid electric vehicle.

  In FIG. 1, a three-phase induction motor 1 is a three-phase induction motor (AC motor). The speed detector 2 is a tachometer that detects the number of rotations (frequency) of the induction motor. The variable frequency inverter 3 is an inverter that drives a three-phase induction motor by converting a direct current into a three-phase alternating current according to a voltage command and a frequency command. The storage battery 4 is a lead battery. The engine 5 is an internal combustion engine. The AC generator 6 is a single-phase or three-phase AC generator. The rectifier 7 is a device that converts alternating current into direct current. The power generation control means 8 is means for efficiently generating power by controlling the engine and the AC generator. The induction motor control means 9 is means for controlling the three-phase induction motor via a variable frequency inverter. The wheel 10 is a wheel of an electric vehicle. Since the basic configuration of each of these elements is well known, detailed description is omitted.

  The function and operation of the series hybrid electric vehicle configured as described above in the embodiment of the present invention will be described. First, an outline of a series hybrid electric vehicle will be described with reference to FIG. The series hybrid electric vehicle includes an engine 5, an AC generator 6 driven by the engine 5, a rectifier 7 connected to the AC generator 6, a variable frequency inverter 3 connected to the rectifier 7, and a variable frequency inverter. 3, a three-phase induction motor 1 connected to 3, a wheel 10 driven by the three-phase induction motor 1, a control device that controls the engine 5, the AC generator 6, the variable frequency inverter 3, and the three-phase induction motor 1; It comprises. The power generation control means 8 of the control device controls the engine 5 and the AC generator 6 to operate at maximum efficiency during constant speed operation other than when the rotational speed is changed. The induction motor control means 9 of the control device drives the three-phase induction motor 1 with the optimum slip in the region of the rotational speed where the efficiency is maximum, and drives with the slip which becomes the maximum torque in the region of the rotational speed where a large torque is required. In the intermediate rotation speed region, control is performed so as to drive with an intermediate slip. The speed command value from the driver is input to the variable frequency inverter 3 as a voltage command. The speed command value with a sign is input to the induction motor control means 9.

  In this example, since no storage battery is provided, regenerative power cannot be stored during deceleration. Therefore, the regenerative power is circulated to the AC generator 6 via the variable frequency inverter 3 and the rectifier 7 so that the AC generator 6 operates as a motor and the engine 5 applies the engine brake. The variable frequency inverter 3 and the rectifier 7 are configured so that regenerative power can be circulated. Alternatively, the regenerative power is heated by a resistor so that the brake is applied during deceleration. The engine 5 that drives the alternator 6 must be driven under optimum conditions at all times because the power required for the three-phase induction motor 1 must be supplied in real time by changing the rotation speed and torque according to the running state. It is not possible. However, by controlling the three-phase induction motor 1 optimally, efficiency and controllability are improved as compared with the case of the engine 5 alone.

  Next, the relationship among slip, efficiency, and torque will be described with reference to FIG. As shown in FIG. 2A, the efficiency is maximized when the slip s is Se. At the operating point with the highest efficiency, the output and torque are lower than rated. At the rated output, the slip s becomes Sr. When the rated output is output, the efficiency is slightly reduced. Furthermore, it may be necessary to temporarily output a large output or torque, and in that case, the efficiency further decreases. When the slip s is Ss, the torque becomes maximum (stop torque). It is useless from the viewpoint of effective use of the function of the motor to operate the induction motor only at the maximum efficiency. When operating with a large output or torque temporarily, the operability and the like are more important than the efficiency. Therefore, at low speed or during cruising, s = Se is operated at maximum efficiency, and at acceleration, s = Ss is operated at maximum torque. In the intermediate transition state, the vehicle operates with an intermediate slip.

  Next, the operation of the series hybrid electric vehicle will be described with reference to FIG. As shown in FIG. 2B, in the case of a low applied voltage (0 to Vm), driving is performed with a slip Se corresponding to the maximum efficiency. In the case of a high applied voltage, driving is performed with a slip Ss corresponding to the maximum torque. In the middle, the driving is performed so that the slip is increased according to the increase of the applied voltage. That is, the maximum efficiency slip value is the optimum slip value in the low voltage region, the maximum torque slip value is the optimum slip value in the high voltage region, and the intermediate slip value between the maximum efficiency slip value and the maximum torque slip value in the intermediate voltage region. Is the optimal slip value. The intermediate slip value is linearly changed according to the voltage change. An optimum slip value corresponding to the applied voltage is obtained, a drive slip frequency is obtained from the rotation speed and the optimum slip value, and is given to the variable frequency inverter as a frequency command. By doing so, it is possible to drive while achieving both efficiency and operability. The specific range of the low voltage region and the high voltage region is determined according to the balance of characteristics, efficiency, and operability of the three-phase induction motor.

  Next, the operation of the induction motor control means of the series hybrid electric vehicle will be described with reference to FIG. The maximum efficiency slip value is stored in advance in the maximum efficiency slip value storage means in accordance with the characteristics shown in FIG. The maximum torque slip value storage means stores the maximum torque slip value according to the characteristics shown in FIG. During operation, the maximum efficiency slip value storage means and the maximum torque slip value storage means are referred to according to the rotational speed detected by the speed detector 2 in FIG. 1 and the applied voltage, and the intermediate slip value calculation means is used as necessary. However, the optimum slip value is obtained by the optimum slip value calculating means. From the optimum slip value and the rotation speed, the optimum slip frequency is calculated by the optimum slip frequency calculating means. The drive frequency is obtained from the rotation speed and the optimum slip frequency, and given to the variable frequency inverter as a frequency command.

  Next, an outline of a modification of the series hybrid electric vehicle will be described with reference to FIG. The configuration of the series hybrid electric vehicle of this modification is basically the same as the above example. The point provided with the storage battery 4 connected to the rectifier 7 and the variable frequency inverter 3 differs from the said basic example. Accordingly, the function of the induction motor control means 9 is slightly different. The storage battery 4 is charged in advance, and power can be supplied to the three-phase induction motor 1 from both the AC generator 6 side and the storage battery 4 during acceleration. Moreover, since the regenerative electric power at the time of deceleration can be stored in the storage battery 4, efficiency increases. Furthermore, by using the storage battery 4, the time for driving the engine 5 with maximum efficiency can be lengthened, so that the fuel consumption rate can be improved.

  Next, the relationship among slip, efficiency, and torque will be described with reference to FIG. The power running operation is the same as that in the basic example. In regenerative operation, the same operation is performed. As shown in FIG. 5A, the efficiency is maximized when the slip s is -Se. At the operating point with the highest efficiency, the output and torque are lower than rated. At the rated output, the slip s becomes -Sr. When the rated output is output, the efficiency is slightly reduced. When the slip s is -Ss, the torque becomes maximum (stop torque). At low speed, s = -Se is operated at maximum efficiency, and at deceleration, s = -Ss is operated at maximum torque. In the intermediate transition state, the vehicle operates with an intermediate slip.

  Next, the operation of the series hybrid electric vehicle will be described with reference to FIG. The power running operation is the same as that in the basic example. In regenerative operation, the same operation is performed. As shown in FIG. 5B, in the case of a low applied voltage (0 to -Vm), driving is performed with a slip -Se corresponding to the maximum efficiency. In the case of a high applied voltage, it is driven with a slip -Ss corresponding to the maximum torque. In the middle, the driving is performed so that the slip is increased according to the increase of the applied voltage. That is, the maximum efficiency slip value is the optimum slip value in the low voltage region, the maximum torque slip value is the optimum slip value in the high voltage region, and the intermediate slip value between the maximum efficiency slip value and the maximum torque slip value in the intermediate voltage region. Is the optimal slip value. The intermediate slip value is linearly changed according to the voltage change. When decelerating, the brake can be applied with a large torque. On long downhills, regenerative power can be obtained efficiently.

  Next, referring to FIG. 5C, a state transition of a modified example of the series hybrid electric vehicle will be described. Start the engine and turn the alternator. The engine is always controlled to operate at maximum efficiency. From the stop state to the cruise state through the acceleration state. In the cruising state, the three-phase induction motor is driven with the maximum efficiency slip, so the power consumption is low. In the acceleration state, the three-phase induction motor is driven by the slip where the torque is maximum, so that the operability is good. Since the regenerative electric power at the time of deceleration is stored in the storage battery and used during traveling, energy efficiency is also good.

  As described above, according to the embodiment of the present invention, a series hybrid electric vehicle is driven with an optimum slip in the region of the rotational speed where the efficiency is maximum, and the slip becomes the maximum torque in the region of the rotational speed where a large torque is required. The induction motor is controlled so that it can be driven with an intermediate slip in the intermediate speed range, so that the engine can be driven with maximum efficiency in almost all time, and the induction motor can be driven with almost maximum efficiency. When accelerating and decelerating, it can operate with good operability.

  The series hybrid electric vehicle of the present invention is most suitable as a small passenger car for home use. It can also be applied to large commercial vehicles such as buses and trucks.

DESCRIPTION OF SYMBOLS 1 Three-phase induction motor 2 Speed detector 3 Variable frequency inverter 4 Storage battery 5 Engine 6 Alternator 7 Rectifier 8 Power generation control means 9 Induction motor control means
10 wheels

Claims (2)

An engine, an AC generator driven by the engine, a rectifier connected to the AC generator, a variable frequency inverter connected to the rectifier, and a three-phase induction motor connected to the variable frequency inverter; In a series hybrid electric vehicle comprising a wheel driven by the three-phase induction motor, a control device for controlling the engine, the AC generator, the variable frequency inverter, and the three-phase induction motor, the control device Is a power generation control means for controlling the engine and the AC generator to operate at maximum efficiency during constant speed operation other than when the rotational speed is changed, and the rotational speed at which the efficiency of the three-phase induction motor is maximized. Drives at the optimum slip in the region, drives at the maximum torque in the region where the rotation speed requires a large torque, and drives at the intermediate rotation region. Series hybrid electric vehicle, characterized in that it comprises an induction motor control means for driving in the middle of sliding. An engine, an AC generator driven by the engine, a rectifier connected to the AC generator, a variable frequency inverter connected to the rectifier, and a storage battery connected to the rectifier and the variable frequency inverter; Control for controlling a three-phase induction motor connected to the variable frequency inverter, wheels driven by the three-phase induction motor, the engine, the AC generator, the variable frequency inverter, and the three-phase induction motor In a series hybrid electric vehicle comprising a device, the control device controls the engine and the AC generator to operate at maximum efficiency during constant speed operation other than when the rotational speed is changed. The three-phase induction motor is driven at an optimal slip in the range of the rotational speed where the efficiency is maximum, and the rotational speed that requires a large torque Driven by sliding with the maximum torque in the region, the series hybrid electric vehicle, characterized in that it comprises an induction motor control means for driving in the middle of the sliding in the region of the intermediate speed.

Images