TWI757391B - A system to control a hybrid vehicle and a method thereof - Google Patents

Abstract

The present invention relates to a control system for a hybrid vehicle and a method thereof. The control system (200) for a hybrid vehicle (100) includes a hybrid control unit (204), a second controller (207), an integrated starter generator unit (203), a traction motor (202), and a power source (201). The control system (200) is capable of controlling and providing power source to the hybrid control unit (204) and the integrated starter generator (203) through the single power source (201). Further, the control system (200) includes a traction motor (202) and said integrated starter generator unit (203) is controlled by the hybrid control unit (204) and the second controller (207) respectively. The single power source (201) saves resources and results in simpler circuitry that is easier to accommodate in the vehicle.

Description

System and method for controlling hybrid vehicle

The subject matter of the present case relates generally to hybrid vehicles, and more particularly and not exclusively to a control system and method therefor.

Generally, a hybrid vehicle includes an internal combustion (IC) engine and a power motor for providing power to the vehicle. The IC engine installed on such a hybrid vehicle uses gasoline/fuel like any other conventional IC engine. The power motor is powered by a power source on the vehicle. The hybrid vehicle is operated using the IC engine, or the power motor, or the IC engine and power motor in combination. The user can operate the hybrid vehicle in any of three modes, ie, an engine mode, an electric mode, and a hybrid mode, as desired. The hybrid mode further includes a hybrid sport mode and a hybrid economy mode. In the hybrid sport mode, the IC engine and power motor arrangements operate in conjunction. In the hybrid economy mode, the IC engine and power motor are operated alternately. If the user desires more power, the vehicle may be operated in the hybrid sport mode.

The lack of sources of non-renewable energy sources has led to a well-known need to reduce the consumption of fossil fuels and emissions from vehicles powered by internal combustion engines. One way to achieve the foregoing is through an electrically powered vehicle. However, such vehicles have greater body weight and shorter driving distance per charge than the conventional vehicle due to limitations in the technology required to manage the battery and the effects of the body weight . This disadvantage is overcome by hybrid vehicles, which utilize the advantages of internal combustion engines and electric power motors into the vehicle. They offer great potential for reducing vehicle fuel consumption and emissions without significant loss of vehicle efficiency or drivability.

Typically, a power source and an internal combustion (IC) engine are used to power a hybrid vehicle. The IC engine is started by running a permanent magnet generator with a battery powered one-start motor. Another battery provides power to the power motor responsible for the rotation of the rear wheels, that is, to provide energy. A hybrid control unit controls both the IC engine and the power motor. After a battery starts the power motor, the power motor also produces some power. Furthermore, the electricity generated by the permanent magnet generator and power motor can be used to power the battery to run the load directly. Both the permanent magnet generator and the power motor generate electricity at higher voltages, ie at about 48-60V.

Thus, it is apparent that a typical hybrid vehicle operating system requires two distinct motors, including a power motor and a starter motor.

The starter motor required to run the permanent magnet generator can be replaced by an integrated starter generator (ISG) that enables smooth starting of the IC engine. The ISG directly rotates the crankshaft, which produces a smooth start of the IC engine. Therefore, ISG is more desirable in a hybrid vehicle.

The ISG and power motor operate at two different voltage levels. Therefore, easier operation of the ISG and power motor in a hybrid vehicle is achieved by utilizing two different power sources with two different voltage levels.

However, the difficulties involved in using two different power supplies to meet the requirements of two different voltage levels and using two different motor trains require a complex circuit. It becomes a laborious task to accommodate this complex circuit within the space in the vehicle layout. Therefore, there is a need for a control system that solves the above problems and provides a small and simple control system to perform operations of different systems.

The ISG, power motor and power supply are controlled by a hybrid control unit. The hybrid control unit includes a built-in DC-DC converter. The single hybrid control unit that controls the components including the ISG, power motor, and power source suffers from overheating problems. This is due to the different operating conditions of components operating at different voltage levels and at different currents. Furthermore, the hybrid control unit suffers from insufficient dissipation of the heat generated in the hybrid control unit due to the operation of high-power electronic switches. For example, in the present example, high power electronic switches including two hex bridge power electronic switches for power conversion generate high heat, and in order to maintain the heat sink provided by the controller housing The thermal resistance is low and a high cross-sectional area must be maintained.

Furthermore, the hybrid control unit performs switching between the control of the power motors operating at different frequencies respectively and the control of the ISG. Due to the switching, the interference of electromagnetic noise is emitted. In order to eliminate the interference of this electromagnetic noise, a filter of huge size is required. Accommodating these huge size filters would make the circuit too bulky and more complex.

Furthermore, switching between the function of the power motor and the function of the ISG involves enabling and disabling power electronic switches, so the power electronic switches include internal body diodes to allow Unbalanced current flows when the switches are disabled. This unbalanced current flow will affect the function of the switches.

Furthermore, the electrical output produced by an ISG controlled by a single hybrid control unit is very low due to the overlap of unwanted harmonics on the desired output.

The aforementioned difficulties involved in using two different power sources in a hybrid vehicle and in a single hybrid control unit operating at different voltages are overcome according to the proposed invention.

According to one embodiment of the present invention, a control system for a hybrid vehicle includes a single power source.

The power train is capable of driving both the power motor and an ISG. The power motor is controlled by a hybrid control unit (HCU), and the ISG is controlled by a second controller. The second controller according to another embodiment is an ISG controller, and a DC-DC converter is configured to convert the high output voltage generated by the ISG to a desired low voltage sufficient to drive vehicle loads.

According to an embodiment of the present invention, a power supply operating at a predetermined voltage, such as 48V, can provide input power to an ISG operating at a lower predetermined voltage, such as 12V, and can provide power to the ISG operating at For example, it is a power motor of the preset voltage of 48V. The high voltage is converted by a circuit before being fed into the ISG. The circuit includes two power modules including a hexagonal bridge configuration for driving the power motor, and a second hexagonal bridge for driving the ISG. The power modules convert the DC input power from the power source into controllable DC output power for driving the power motor, which in this example is a BLDC motor. The DC input sides of the first and second power modules include individual DC link capacitors for filtering, and a current sense resistor for providing information about the input power to the power motor and ISG. Furthermore, the power electronic switches include one or more internal body diodes for providing a current path during current circulation when the switches are disabled. In particular, the power electronic switches are driven through specific gate driver ICs. The gate driver ICs are further controlled by inputs supplied by a control module.

Furthermore, the control module includes a microcontroller and a corresponding power supply module. Additionally, inputs from vehicle operating conditions such as accelerator, vehicle speed, engine speed, ignition, braking are fed to the microcontroller ports as analog and digital inputs.

Furthermore, the operation of the power motor and ISG is controlled by closed-loop parameters that depend on vehicle operating conditions. The input to the power motor and the ISG is the power fed from the single power source through the controller. The outputs of the power motor and ISG are mechanical power, which are measured in terms of vehicle speed, wheel force, and engine speed and rotational torque, respectively.

Furthermore, in order to control the ISG machine to achieve the required current, the input voltage fed to the ISG is controlled through a pulse width modulated switching technique.

Furthermore, the duty cycle of the operation of the power electronic switch is controlled by monitoring the output speed of the ISG.

The previously mentioned advantages and other advantages of the present subject matter are described in detail in the following description in conjunction with the drawings.

FIG. 1 is a left side view depicting an example vehicle 100 in accordance with an embodiment of the present subject matter. The depicted vehicle 100 has a straddle-type frame assembly 105 . The straddle type frame assembly 105 includes a head tube 105A and a main frame 105B. One or more rear tubes 105C extend obliquely rearward from the main tube 105B. Furthermore, one or more front suspensions 110A are connected to a front wheel 110B, and a handle assembly 110C constitutes a control assembly 110 . The steering assembly 110 is rotatably connected through the head tube 105A. An IC engine 115 functions as a main driving means for driving a rear wheel 125 . Furthermore, a power motor 120 is used as a secondary driving means for driving the rear wheel 125 . In a preferred embodiment, the power motor 120 is hub mounted on the rear wheel 125 . An on-board battery 170 (not shown) drives the power motor 120 . In one embodiment, the IC engine 115 is mounted to a swing arm 130 that is swingably connected to the main frame 105B using a toggle link. The vehicle 100 is provided with a plurality of body panels mounted to the frame assembly 105, and the plurality of body panels include a front panel 135A, a leg shield 135B, an underseat cover 135C, and a Opposite side panel 135C.

A front fender 140 covers at least a portion of the front wheel 110A. A floor 145 is provided in the overpass space, which is provided behind the handle assembly 110C. A seat assembly 150 is mounted to the main frame 105B. A storage compartment (not shown) is provided below the seat assembly 150 . A fuel tank (not shown) is positioned below the storage compartment. A rear fender 155 covers at least a portion of the rear wheel 125 and is positioned below the fuel tank. One or more rear suspensions 160 are provided in the rear portion of the vehicle 100 for a comfortable ride. The vehicle 100 includes one or more electrical/electronic loads 165 (hereafter referred to as 'loads') including, for example, a headlight 165A, a taillight 165B, a transistor controlled ignition (TCI) unit (not shown) ), an alternator (not shown), and a starter motor (not shown).

FIG. 2 is a block diagram depicting a control system for a hybrid vehicle according to an embodiment. According to an embodiment of the present invention, a battery acting as a power source 201 powers two 3-phase machines including a power motor 202 and an integrated starter generator (ISG) 203 . A hybrid control unit (HCU) 204 controls the operation of the power motor 202 through various inputs received by the HCU 204 . The various inputs include a throttle position sensor, ignition lock, a rpm input, a mode switch, and brakes.

According to another embodiment of the present invention, the power supply 201 preferably operating at 48V is capable of powering the power motor 202 operating at 48V and the ISG 203 operating at 12V. The ISG 203 produces an output voltage of 12V. The output voltage 12V generated by the ISG 203 is sufficient to operate the loads 206 operating at 12V. The output voltage 12V generated by the ISG 203 is transmitted to the loads 206 through a second controller 207 . The second controller 207 is preferably an ISG controller and a DC-DC converter. The second controller 207 also controls the operation of the ISG 203 . Various loads powered by the output of the ISG 203 and controlled by the second controller 207 include an engine speed reader, ignition lock checks, a cluster of equipment, and various vehicle loads.

According to another embodiment of the present invention, the hybrid control unit 204 is configured to directly operate the loads 206 operating at 12V.

Since a single power source including the battery 201 is configured to power the power motor 202 and the ISG 203 in a hybrid vehicle, a simple and cost-effective system is obtained.

FIG. 3 is a circuit diagram depicting a control system for controlling a hybrid vehicle in different operating modes. The control system 200 includes a 48V auxiliary single power supply 201, such as a battery, a rechargeable energy storage system. Furthermore, the control system 200 includes a hybrid control unit 204, which includes an integrated starter generator control module 204b, a power motor control module 204a, and a DC-DC converter 204c. The integrated starter generator control module 204b is configured to control an integrated starter generator 203 which is operable at 48V and capable of producing a 12V output. The 12V output thus produced by the integrated starter generator 203 is used to power one or more DC loads operable at 12V. Whenever the mode switch is selected as a hybrid mode including a hybrid economy mode and a hybrid sport mode (depending on the conditions selected by the user), the integrated starter generator 203 is activated by the integrated The generator controller 204b is switched on and turned on. Furthermore, the control system 200 includes a power motor 202 controlled by the power motor controller 204a. When the user selects the desired mode through the mode switch, especially during the electric mode of the hybrid vehicle and during the hybrid sport mode, the 48V-operable power motor 202 is powered by the 48V single power supply be powered. Furthermore, whenever the power motor 202 is disabled during the hybrid economy mode, it is then able to generate electricity capable of powering the 48V power supply. Furthermore, the DC-DC converter 204c also helps to step down a very high output produced by the power motor 202 into a 12V DC output, which can power one or more DC vehicle loads 206.

According to an embodiment of the present invention, the 48V single power supply 201 is capable of powering the one or more 12V DC vehicle loads 206 .

According to another embodiment of the present invention, the DC-DC controller 204c is not part of the hybrid control unit 200 .

According to an embodiment of the present invention, the DC-DC controller 204c is a built-in part of the second controller 207 .

4 is a diagram depicting a method of operation of a hybrid control unit and a second controller powered by a single power source. According to an embodiment of the present invention, a single power source including a battery powers the power motor and the integrated starter-generator. First, at step 301, the function of the hybrid control unit is activated and the ignition lock is checked at step 302 for ON/OFF. If the ignition switch is ON, the HCU is switched to any one of three modes of a hybrid vehicle at the mode switch 303, the three modes of the hybrid vehicle include an EV mode (electric vehicle mode), a hybrid mode, and an engine mode. The hybrid mode further includes a hybrid economy mode and a hybrid sport mode, which can be selected by the user according to the provided conditions. Whenever the vehicle is operating in an electric mode as indicated in step 304 , the HCU checks whether the throttle position sensor (TPS) is greater than a preset value as indicated in step 305 . If the TPS reading is greater than 5%, then the power motor is turned on by the HCU, and the power motor is powered by a single power source as indicated in step 307 . As indicated in this step 308, the output of the power motor is used to operate the loads operating at 12 volts. Furthermore, if the mode switch detected in step 304 is not the electric mode, then the vehicle is operating in the hybrid mode or the engine mode. If the mode switch is selected for hybrid mode as indicated in step 306, the vehicle is operated in the hybrid economy mode as indicated in step 306a, then the TPS is operated by the HCU to check. If the TPS reading is greater than 5% as indicated in step 309 , then the power motor is powered by a single power source through an HCU as indicated in step 310 . Furthermore, if the speed of the vehicle exceeds a preset value, such as 25kmph, as indicated in step 311, the engine is started via the single power source as indicated in step 312, and the operation The power motor system is stopped. Once the engine is running, the power generated by the operation of the engine is used to power the 12V loads as indicated in step 313 .

Furthermore, after the mode switch relationship is selected for the hybrid mode as indicated in step 306 and not for the hybrid economy mode, the hybrid sport mode is selected as indicated in step 314 . In the hybrid sport mode, the TPS is checked, and if the TPS is greater than 5%, the second controller simultaneously activates the ISG and the power motor through the single power source as indicated in step 315 of power supply. Again, after power generation is initiated through the ISG and powered motor, the power so generated is used to power the 12V loads as indicated in step 316 .

If the mode switch selected is not a hybrid mode, then the engine mode is selected. Furthermore, the TPS system is constantly monitored. If the TPS is greater than 5% as indicated in step 317 , then the vehicle's engine is started by powering the ISG from the single power source through the second controller as indicated in step 318 . Furthermore, the power generated by the ISG can run a 12V load in the vehicle. In this step, both the engine and the power motor are started from a single power source. The power generated is used to operate the 12V loads as indicated in step 315 .

Since a single power source including the battery 201 is configured to power the power motor 202 and the ISG 203 in a hybrid vehicle, a simple and cost-effective system is obtained.

Although the subject matter has been described in considerable detail with reference to certain embodiments thereof, other embodiments are possible. It will be appreciated that the features of the embodiments are not necessarily limited to those described herein.

100‧‧‧Hybrid Vehicles 105‧‧‧Stride Type Frame Assembly 105A‧‧‧Head Tube 105B‧‧‧Main Frame 105C‧‧‧Rear Tube 110‧‧‧Control Assembly 110A‧‧‧Front Suspension 110B‧‧‧Front Wheel 110C‧‧‧Handle Assembly 115IC‧‧‧Engine 120‧‧‧Power Motor 125‧‧‧Rear Wheel 130‧‧‧Swing Arm 135A‧‧‧Front Panel 135B‧‧‧Leg Guard 135C‧‧ ‧Covers under the seats (side panels) 140‧‧‧Front fenders 145‧‧‧floor 150‧‧‧Seat assemblies 155‧‧‧Rear fenders 160‧‧‧Rear suspension 165‧‧‧ Motor/Electronic Load 165A‧‧‧Headlight 165B‧‧‧Taillight 170‧‧‧Battery 200‧‧‧Control System 201‧‧‧Power Supply 202‧‧‧Power Motor 203‧‧‧Integrated Starter Generator Unit (ISG) 204‧‧‧Hybrid Control Unit (HCU) 204a‧‧‧Power Motor Control Module 204b‧‧‧Integrated Starter Generator Control Module 204c‧‧‧DC-DC Converter 206‧‧‧Load 207‧‧‧ Steps

A detailed description of a control system and method thereof, which is the subject of this application, is described with reference to the accompanying drawings. The same reference numerals are used throughout the drawings to refer to similar features and components. FIG. 1 is a left side view depicting as an example a step-through type vehicle in accordance with one embodiment of the present subject matter. FIG. 2 is a block diagram depicting the operation of a hybrid control unit. 3 is a circuit diagram depicting a control system for controlling a hybrid vehicle in different operating modes. 4 is a method depicting the operation of an HCU powered by a single power supply.

200‧‧‧Control system

201‧‧‧Power

202‧‧‧Power Motor

203‧‧‧Integrated Starter Generator Unit (ISG)

204‧‧‧Hybrid Control Unit (HCU)

204a‧‧‧Power Motor Control Module

204b‧‧‧Integrated starter generator control module

204c‧‧‧DC-DC Converter

206‧‧‧Load

207‧‧‧Second Controller

Claims (10)

A hybrid vehicle (100) comprising: a control system (200) for controlling the hybrid vehicle (100), the control system (200) comprising a A hybrid control unit (HCU) (204) for switching between operating modes, an integrated starter generator (ISG) (203) coupled to an internal combustion engine (115) of the hybrid vehicle (100) ), a power motor ( 202 ) capable of driving the hybrid vehicle ( 100 ) independently and in combination with the internal combustion engine ( 115 ), and a single power source ( 201 ), wherein the power motor ( 202 ) and the integrated Both the integrated starter generators (203) receive power supply from the single power source (201), and the power motor (202) is controlled by the hybrid control unit (204), and the integrated starter generators (203) ) is controlled by a second controller (207) independent of the hybrid control unit (204) to independently power one or more vehicle loads (206) by means of the integrated starter generator (203) The generated output voltage is transmitted through the second controller (207) to the one or more vehicle loads (206). As in the hybrid vehicle (100) of claim 1, the power motor (202) can supply power to the one or more vehicle loads (206) through the second controller (207), and the power motor ( 202) The single power source (201) can be charged during the power generation of the power motor (202). The hybrid vehicle (100) of claim 1, wherein the second controller (207) includes a built-in DC-DC converter (204c). As in the hybrid vehicle (100) of claim 1, wherein the single power source (201) generating a predetermined output voltage that is fed through a circuit to the integrated starter generator (203) operating at a lower predetermined voltage, the circuit comprising at least A hexagonal bridge capable of driving the power motor (202), and a second hexagonal bridge configured to drive the integrated starter generator (203). The hybrid vehicle (100) of claim 2, wherein the single power source (201) is capable of powering the one or more loads (206) of the vehicle. A method for controlling a hybrid vehicle, the method comprising the steps of: monitoring (302) an ignition switch state and a throttle position sensor state by a hybrid control unit (204); if the ignition switch state If the state of the ignition lock is turned on through a mode switch (303), the HCU (204) is used to activate the load of the vehicle. Switch (303) to any one of the three modes of the hybrid vehicle (100); if EV mode is selected through the HCU (204) and if the TPS is greater than a preset value, switch on a power Motor (308); if TPS is greater than a preset value and if speed is greater than a preset value, switch to hybrid mode (306) through the HCU (204); if the EV mode and the hybrid mode (306) is not detected, switching to engine mode (320) through the second controller (207); and if any of the three modes is selected through the HCU (204), One or more vehicle loads (206) are enabled through the single power supply (201), and the one or more vehicle loads (206) are controlled through the second controller (207), wherein the single A power source (201) is configured to provide power to an engine (115) by supplying an integrated starter-generator (203), wherein the integrated starter-generator (203) is operated independently of the hybrid control unit ( 204) to be controlled by the second controller (207) so as to independently Powering the load (206) of the one or more vehicles on site, wherein the output voltage generated by the integrated starter generator (203) is transmitted to the one or more vehicles through the second controller (207) load (206). The method for controlling a hybrid vehicle (100) of claim 6, wherein whenever the vehicle operates in an electric mode as indicated in step (304), the hybrid control unit (204) Check if the throttle position sensor is greater than a preset value as indicated in step (305). The method for controlling a hybrid vehicle (100) of claim 6, wherein if the mode switch is selected for a hybrid economy mode as indicated in step (306a), the hybrid The power control unit ( 204 ) checks whether TPS is greater than 5% as indicated in step ( 309 ) to power the power motor ( 202 ) from a single power source ( 201 ). A method for controlling a hybrid vehicle (100) as claimed in claim 6, wherein if the speed of the vehicle in the hybrid sport mode is beyond a preset of 25Kmph as indicated in step (314) , the single power source (201) is configured to enable the power motor (202) through the second controller (207). The method for controlling a hybrid vehicle (100) as claimed in claim 6, wherein if the selected mode is not the electric mode (304) and the non-hybrid mode (306), the mode switch (303) switches To an engine mode (320), the second controller (207) monitors the TPS as indicated in step (317), and if the TPS is greater than a preset value, only the engine (115) operates through the A single power source (201) powers the integrated starter generator (203) for starting.

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