CN116317714A - Motor controller, control method thereof and electric automobile - Google Patents

Motor controller, control method thereof and electric automobile Download PDF

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Publication number
CN116317714A
CN116317714A CN202310041897.1A CN202310041897A CN116317714A CN 116317714 A CN116317714 A CN 116317714A CN 202310041897 A CN202310041897 A CN 202310041897A CN 116317714 A CN116317714 A CN 116317714A
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CN
China
Prior art keywords
motor controller
switching tube
circuit
direct current
motor
Prior art date
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Pending
Application number
CN202310041897.1A
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Chinese (zh)
Inventor
钟小帆
林霄喆
于海生
郑富辉
张兴林
罗春李
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Wuxi Xingqu Power Technology Co ltd
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Wuxi Xingqu Power Technology Co ltd
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Priority to CN202310041897.1A priority Critical patent/CN116317714A/en
Publication of CN116317714A publication Critical patent/CN116317714A/en
Pending legal-status Critical Current

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
    • H02P6/08—Arrangements for controlling the speed or torque of a single motor
    • H02P6/085—Arrangements for controlling the speed or torque of a single motor in a bridge configuration
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0063—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with circuits adapted for supplying loads from the battery
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0048—Circuits or arrangements for reducing losses
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/36—Means for starting or stopping converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • H02M3/1582—Buck-boost converters

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)

Abstract

The embodiment of the application provides a motor controller, a control method thereof and an electric automobile. The motor controller is applied to an electric automobile and is connected between a battery and a motor. The motor controller includes an inverter circuit, a step-down circuit, and a bypass circuit. The inverter circuit is connected between the DC bus and the motor and is used for converting the DC into AC for driving the motor to work. The step-down circuit is positioned at the front stage of the inverter circuit and connected between the battery and the direct current bus for reducing the voltage on the direct current bus. The bypass circuit is positioned at the front stage of the inverter circuit and connected in parallel with the step-down circuit for bypassing or enabling the step-down circuit according to different operation modes. According to the embodiment of the application, the loss of the electric control system can be reduced, and the efficiency of the electric control system is improved.

Description

Motor controller, control method thereof and electric automobile
Technical Field
The embodiment of the application relates to the technical field of automobiles, in particular to a motor controller, a control method thereof and an electric automobile.
Background
Along with the rapid development of the new energy automobile industry, the energy consumption of the whole automobile is required to be smaller and smaller. The efficiency requirements for the inverter (motor controller) and the motor, which are one of the core components of the electric vehicle powertrain, are also increasing.
As the motor and motor controller (the other is a decelerator) among three major components of the electric vehicle powertrain system, it is necessary to consider the total (electric) efficiency from the system point of view, not just the high efficiency of one of the components.
Currently, the motor controller typically employs the topology shown in fig. 1, whether it is a 400V platform battery pack or an 800V platform battery pack. As shown in fig. 1, a motor controller 30 is located between the battery 10 and the motor 20, the motor controller 30 includes an inverter 31, and if a third generation semiconductor switching device, i.e., a SiC MOS switching device (MOSFET, metal-Oxide-Semiconductor Field-Effect Transistor, metal-Oxide semiconductor field effect transistor) is used as the power switching devices Q1 to Q6 in the inverter 31, the motor controller is typically applied to an 800V platform vehicle type. If the power switching devices Q1-Q6 in fig. 1 are IGBTs (Insulated-Gate Bipolar Transistor), they are commonly used in a 400V platform vehicle.
The loss of the motor controller is related to a plurality of factors, so how to reduce the loss of the electric control system and improve the efficiency of the electric control system becomes a great problem to be solved.
Disclosure of Invention
An object of the embodiment of the application is to provide a motor controller, a control method thereof and an electric automobile, which can reduce the loss of an electric control system and improve the efficiency of the electric control system.
An aspect of the embodiments of the present application provides a motor controller, which is applied to an electric automobile and is connected between a battery and a motor. The motor controller comprises an inverter circuit, a voltage reduction circuit and a bypass circuit. The inverter circuit is connected between the direct current bus and the motor and is used for converting direct current into alternating current so as to drive the motor to work. The step-down circuit is positioned at the front stage of the inverter circuit and connected between the battery and the direct current bus for reducing the voltage on the direct current bus. The bypass circuit is positioned at the front stage of the inverter circuit and connected in parallel with the step-down circuit, and is used for bypassing or enabling the step-down circuit according to different working modes.
Another aspect of the embodiments of the present application further provides an electric vehicle. The electric automobile comprises the motor controller, the battery and the motor, wherein the motor controller is connected between the battery and the motor.
In a further aspect of the embodiments of the present application, a control method of a motor controller is further provided, and the motor controller is applied to an electric vehicle, where the motor controller is connected between a battery and a motor. The control method comprises the following steps: when the first output requirement of the motor needs to be met, controlling the motor controller to work in a first working mode so that the direct current bus has a first direct current bus voltage; and when the second output requirement of the motor needs to be met, controlling the motor controller to work in a second working mode so that the direct current bus is provided with a second direct current bus voltage, wherein the first direct current bus voltage is greater than or equal to the second direct current bus voltage.
According to the motor controller, the control method thereof and the electric vehicle, the primary voltage reduction circuit and the bypass circuit are additionally arranged at the front stage of the original inverter circuit, so that the problem that the loss of an electric control system becomes high under the condition that the voltage of a battery pack of a new energy vehicle is increased to 800V from a 400V platform to a high-voltage platform such as a low-torque motor and a low-power motor is output can be solved.
According to the motor controller and the control method thereof and the electric automobile, the loss of the electric control system can be reduced, and the efficiency of the electric control system is improved.
Drawings
Fig. 1 is a schematic circuit diagram of a conventional motor controller.
Fig. 2 is a schematic circuit diagram of a motor controller according to one embodiment of the present application.
Fig. 3 is a schematic circuit diagram of a motor controller according to another embodiment of the present application.
Fig. 4 is a schematic circuit diagram of a motor controller according to yet another embodiment of the present application.
Fig. 5 is a flowchart of a control method of a motor controller according to an embodiment of the present application.
Detailed Description
Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus consistent with some aspects of the present application as detailed in the accompanying claims.
The terminology used in the embodiments of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Unless defined otherwise, technical or scientific terms used in the embodiments of the present application should be given the ordinary meaning as understood by one of ordinary skill in the art to which the present application belongs. The terms "first," "second," and the like in the description and in the claims, are not used for any order, quantity, or importance, but are used for distinguishing between different elements. Likewise, the terms "a" or "an" and the like do not denote a limitation of quantity, but rather denote the presence of at least one. "plurality" or "plurality" means two or more. Unless otherwise indicated, the terms "front," "rear," "lower," and/or "upper" and the like are merely for convenience of description and are not limited to one location or one spatial orientation. The word "comprising" or "comprises", and the like, means that elements or items appearing before "comprising" or "comprising" are encompassed by the element or item recited after "comprising" or "comprising" and equivalents thereof, and that other elements or items are not excluded. The terms "connected" or "connected," and the like, are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any or all possible combinations of one or more of the associated listed items.
The losses of the motor controller are related to a number of factors such as circuit topology, device type, switching frequency, dc bus voltage, etc. Under the condition that the circuit topology, the device type and the switching frequency are all determined, the biggest factor which can further influence the working efficiency of the motor controller and the motor is direct current bus voltage, and the direct current bus voltage can directly influence the duty ratio of the power device.
In general, the higher the dc bus voltage is, the switching loss of the power device increases synchronously, i.e. the working efficiency of the motor controller is related to the dc bus voltage.
Under the output voltage requirement of the same motor controller, different direct current bus voltages correspond to different switch duty ratios, and the higher the direct current bus voltage is, the smaller the switch duty ratio is. The smaller the duty cycle, the higher the output voltage harmonic content, resulting in higher losses in the motor. The voltage of the direct current bus can directly influence the working efficiency of the motor, namely, under the condition of the same torque or power output, different motor controller output voltage waveforms (distortion degrees) can obtain different total efficiencies. Under certain output requirements, the main factor determining the efficiency of different systems is the dc bus voltage of the motor controller. In the case where there is no step-up/step-down circuit between the motor controller input stage and the battery pack, the dc bus voltage may be considered to be equivalent to the battery pack voltage, which varies with the battery pack SOC (State Of Charge) State.
As the battery pack voltage platform is increasingly developed from 400V level to 800V level, the effect of battery voltage on the operating efficiency of the electronic control system (including the motor and motor controller) will become more apparent.
As is known from the operating principle of switching devices such as IGBTs and SiC MOS, the higher the dc side bus voltage is, the larger the switching loss of the switching device becomes.
Similarly, as the voltage of the bus at the direct current side is higher, the smaller the duty ratio of the switching device of the motor controller is, the larger the pulsation of the output voltage is, the higher the voltage harmonic content is, and the loss of the motor is increased under the condition of the same motor torque and power output.
Therefore, based on the above two factors affecting the working efficiency of the electric control system, the application provides an improved topology of the motor controller and a control method thereof, which can work under specific conditions to reduce the voltage of the direct current bus so as to achieve the purposes of reducing the system loss and improving the system efficiency.
The embodiment of the application provides a motor controller 40, which is applied to an electric automobile. Fig. 2 discloses a schematic circuit diagram of a motor controller 40 according to one embodiment of the present application. As shown in fig. 2, a motor controller 40 is connected between the battery 10 and the motor 20. The motor controller 40 of one embodiment of the present application includes an inverter circuit 41, a BUCK (BUCK) circuit 42, and a bypass circuit 43. An inverter circuit 41 is connected between a direct current bus (DC-Link) (not numbered) and the motor 20 for converting direct current into alternating current for driving the motor 20 to operate. The step-down circuit 42 is located at a front stage of the inverter circuit 41 and is connected between the battery 10 and the dc bus, and may be used to reduce the voltage on the dc bus. The bypass circuit 43 is located at a front stage of the inverter circuit 41 and is connected in parallel with the step-down circuit 42, and may bypass or enable the step-down circuit 42 according to different operation modes.
The motor controller 40 of the present application has a first mode of operation and a second mode of operation. Wherein, when the motor controller 40 is in the first operation mode, the bypass circuit 43 is closed, and the bypass circuit 43 bypasses the step-down circuit 42; when the motor controller 40 is in the second operation mode, the bypass circuit 43 is turned off and the step-down circuit 42 operates.
When the motor controller 40 is in the first operating mode, the dc bus has a first dc bus voltage thereon; when the motor controller 40 is in the second operation mode, the dc bus has a second dc bus voltage, where the first dc bus voltage is greater than or equal to the second dc bus voltage.
For example, when in a high torque and high power demand, the motor controller 40 may operate in a first mode of operation, wherein the bypass circuit 43 is closed and the step-down circuit 42 is not operating, the bypass circuit 43 communicates the battery 10 with the inverter circuit 41, so that the inverter circuit 41 operates in a manner consistent with the conventional voltage, thereby meeting the high rotational speed, high torque and high power output demands.
When the motor controller 40 is operating in the second mode of operation at low or medium torque and low or medium power demands, the bypass circuit 43 is open and the dc bus voltage can be reduced by the step-down circuit 42, thereby improving inverter efficiency and motor 20 efficiency.
The motor controller 40 of the embodiment of the application is provided with the primary step-down circuit 42 and the bypass circuit 43 at the front stage of the original inverter circuit 41, so that the problem that the loss of an electric control system becomes high under the condition that the motor 20 outputs small and medium torque and small and medium power when the battery pack voltage of the new energy automobile is increased to a high-voltage platform of 800V from a 400V platform can be solved.
As shown in fig. 2, the inverter circuit 41 includes a first capacitor C1 and three operating arms connected in parallel. The first capacitor C1 and the three working bridge arms are connected in parallel between the positive electrode end and the negative electrode end of the direct current bus. Each of the three working bridge arms comprises two power switching tubes connected in series. In one embodiment, each working leg includes two SiC MOS switching tubes in series. For example, the first working leg includes SiC MOS switches Q1 and Q2 connected in series, the second working leg includes SiC MOS switches Q3 and Q4 connected in series, and the third working leg includes SiC MOS switches Q5 and Q6 connected in series. Of course, in another embodiment, each working leg in inverter circuit 41 may also comprise two IGBTs in series. The midpoints of the three working legs are used to output ac power and are connected to motor 20.
In some embodiments, the step-down circuit 42 of the present application includes a main switching tube (for example, may be referred to as a first switching tube) Q7, a freewheeling tube Q8, an inductor L, and a second capacitor C2, where the second capacitor C2 is connected in parallel between the positive electrode and the negative electrode of the battery 10, the main switching tube Q7 and the freewheeling tube Q8 are connected in series with each other and then connected in parallel between the positive electrode and the negative electrode of the battery 10, and the inductor L is connected between a connection point between the main switching tube Q7 and the freewheeling tube Q8 and the positive electrode of the dc bus.
In one embodiment, the main switch tube Q7 may comprise a SiC MOS switch tube, so that the working loss of the circuit can be greatly reduced. For example, the main switching transistor Q7 may include a first NMOS switching transistor, a gate of which may be connected to a first driving circuit (not shown), a drain of which is connected to the positive electrode of the battery 10, and a source of which is connected to the junction transistor Q8.
In some embodiments, the follow tube Q8 may include a second switching tube. In one embodiment, the second switching tube may comprise a SiC MOS switching tube. For example, the freewheel tube Q8 may include a second NMOS switching tube, a gate of which may be connected to a second driving circuit (not shown), a drain of which is connected to the main switching tube Q7, and a source of which is connected to the negative electrode of the battery 10.
The freewheeling tube Q8 can use the SiC MOS switch tube, and freewheels through the MOS tube channel by the synchronous rectification control method, so that the freewheeling function of the diode is realized, and lower loss is realized.
The step-down circuit 42 of the embodiment of the present application may further include a filter capacitor, wherein the first capacitor C1 in the inverter circuit 41 may be used as the filter capacitor in the step-down circuit 42 at the same time.
When the bypass circuit 43 is closed, the first capacitor C1 and the second capacitor C2 are connected in parallel. The bypass circuit 43 can realize the circuit for connecting the battery 10 and the inverter circuit 41 when the step-down circuit 42 does not need to work, realize the parallel connection of the first capacitor C1 and the second capacitor C2, and meet the voltage and current requirements of high torque and high power output of the inverter. The bypass circuit 43 can simultaneously provide a short circuit path for the step-down circuit 42 to further reduce the loss caused by the inductance L at a high current, and reduce the size of the inductance L. Because of the bypass circuit 43, the step-down circuit 42 devices may be sized smaller to meet medium-low torque and power requirements for cost optimization.
In some embodiments, the bypass circuit 43 includes a switching tube Q9 and a driving circuit (not shown) for driving the switching tube Q9. The switching tube Q9 of the bypass circuit 43 has a control end, a first end and a second end, wherein the control end of the switching tube Q9 is connected to the driving circuit, the first end of the switching tube Q9 is connected to the positive electrode of the battery 10, and the second end of the switching tube Q9 is connected to the positive electrode of the dc bus. In one embodiment, the switching tube Q9 in the bypass circuit 43 may include a SiC MOS switching tube.
Fig. 3 discloses a schematic circuit diagram of a motor controller 40 according to another embodiment of the present application. As shown in fig. 3, the difference from that shown in fig. 2 is that in the embodiment of the motor controller 40 shown in fig. 3, the switching tube Q9 in the bypass circuit 43 may include an IGBT.
The switching tube Q9 in the bypass circuit 43 in this embodiment of the present application does not need to perform high-frequency switching operation, and has no very high switching loss, so that the switching loss is small, and in order to reduce the system cost, an IGBT with a stronger through-current capability may be preferentially used as the switching device. The IGBT has the advantage of higher cost performance.
Fig. 4 discloses a schematic circuit diagram of a motor controller 40 according to a further embodiment of the present application. As shown in fig. 4, the difference from that shown in fig. 3 is that in the embodiment of the motor controller 40 shown in fig. 4, the follow current pipe Q8 may include a follow current diode, so that the control complexity may be reduced. The positive electrode of the flywheel diode is connected with the negative electrode of the battery 10, and the negative electrode of the flywheel diode is connected with the main switching tube Q7. For example, the freewheeling diode may include a SiC diode.
The motor controller 40 of the present application is not limited to the three embodiments shown in fig. 2 to 4, and in other embodiments of the present application, the embodiments shown in fig. 2 to 4 may be used in combination. The continuous flow tube in the step-down circuit 42 added by the motor controller 40 can be selected from a SiC diode or a SiC MOS switch tube, wherein the SiC diode can simplify control and reduce cost, and the SiC MOS can further reduce loss.
The bypass circuit 43 added to the motor controller 40 of the present application may preferably select an IGBT to meet the cost consideration, or may select an SiC MOS switch under the condition that the cost of the SiC MOS switch meets the requirement.
The motor controller 40 according to the embodiment of the present application can effectively improve the efficiency of the electric drive system under medium-low torque and power requirements by adding the step-down circuit 42.
The motor controller 40 of the present embodiment can meet the high voltage operation requirement of the electric drive system under the requirements of high torque and high power by adding the bypass circuit 43.
The step-down circuit 42 added to the motor controller 40 according to the embodiment of the present application may also preferably use SiC devices, so as to minimize the increase of extra loss.
The motor controller 40 in the embodiment of the present application splits the original dc bus capacitor of the controller into two capacitors, namely, a first capacitor C1 and a second capacitor C2, where the first capacitor C1 is still used as a supporting capacitor of the inverter, and the second capacitor C2 is used as a supporting capacitor of the step-down circuit 42 when the step-down circuit works; alternatively, when the bypass circuit 43 is closed, the first capacitor C1 and the second capacitor C2 are connected in parallel to be used as a supporting capacitor of the inverter, so that the inverter can be ensured to work normally under the conditions of high torque and high power. By the above measures, an increase in the total capacitance of the controller due to the addition of the front stage step-down circuit 42 is effectively avoided.
The motor controller 40 of the embodiment of the application can be suitable for a vehicle type of an 800V high-voltage battery pack platform, a third-generation semiconductor device SiC MOS switching tube can be adopted in the motor controller 40 as a switching device, and compared with the IGBT switching device, the switching loss under high voltage can be effectively reduced by using the SiC MOS switching tube.
Although at high torque and high power demands, the motor controller 40 of the embodiment of the present application appropriately increases its conduction loss due to the addition of the switching devices of the bypass circuit 43. However, in view of the conventional operation conditions, the electric drive system is operated under the conditions of medium torque and medium power for a longer time, and the loss can be obviously reduced as a whole. Typically, the working efficiency is improved according to the working condition assessment of CLTC (China light automobile driving).
In the embodiment of the application, through strict simulation and calculation, the working efficiency of the whole electric control system is improved after the step-down circuit 42. That is, the loss of both the inverter and the motor 20 due to the reduction of the dc bus voltage can completely cancel the loss increased by the operation of the step-down circuit 42, and there is a margin to increase the overall efficiency from the electronic control system.
The motor controller 40 of the embodiment of the present application can effectively improve the working efficiency of the system (including the inverter, the motor 20 and the added circuit itself), improve the endurance mileage of the electric vehicle, or reduce the capacity usage of the battery 10, and bring gain to the product.
The embodiment of the application also provides an electric automobile. The electric vehicle includes the motor controller 40, the battery 10, and the motor 20 according to the above embodiments, wherein the motor controller 40 is connected between the battery 10 and the motor 20.
The electric vehicle of the present embodiment has substantially similar advantageous technical effects as the motor controller 40 described above, and thus, will not be described herein.
The embodiment of the application also provides a control method of the motor controller. Fig. 5 discloses a flowchart of a control method of the motor controller according to an embodiment of the present application. As shown in fig. 5, the control method of the motor controller according to one embodiment of the present application may be applied to an electric vehicle, which includes steps S11 to S13.
In step S11, the output demand of the motor 20 is determined.
In step S12, when the first output requirement of the motor 20 needs to be met, the motor controller 40 is controlled to operate in the first operation mode so that the dc bus has the first dc bus voltage.
In step S13, when the second output requirement of the motor 20 needs to be met in step S12, the motor controller 40 is controlled to operate in the second operation mode so that the dc bus has the second dc bus voltage, where the first dc bus voltage is greater than or equal to the second dc bus voltage.
In some embodiments, the first output demand may include a first torque and a first power demand, and the second output demand may include a second torque and a second power demand, wherein the first torque is greater than the second torque and the first power is greater than the second power. For example, the first output demand is a high torque and high power output demand, and the second output demand is a medium torque and medium power output demand.
In some embodiments, the motor controller 40 includes an inverter circuit 41, a step-down circuit 42, and a bypass circuit 43, wherein the step-down circuit 42 and the bypass circuit 43 are located at a front stage of the inverter circuit 41. Controlling the motor controller 40 to operate in the first operation mode in step S12 may include: the bypass circuit 43 is controlled to be closed, the step-down circuit 42 is bypassed by the bypass circuit 43, and the bypass circuit 43 communicates the battery 10 with the circuit of the inverter circuit 41. Controlling the motor controller 40 to operate in the second operation mode in step S13 may include: the control bypass circuit 43 is turned off and controls the step-down circuit 42 to operate to reduce the voltage on the dc bus.
In some embodiments, the voltage step-down circuit 42 may include a first switching tube and a second switching tube connected in parallel between the positive and negative poles of the battery 10. Wherein controlling the operation of the step-down circuit 42 includes: the on and off of the first switching tube and the second switching tube are controlled according to a preset duty ratio, wherein when the first switching tube is controlled to be on, the second switching tube is controlled to be off; when the first switching tube is controlled to be turned off, the second switching tube is controlled to be turned on, so that the purpose of reducing the voltage of the direct current bus is achieved.
In other embodiments, the voltage step-down circuit 42 may include a main switching tube Q7 and a freewheeling diode connected in parallel between the positive and negative poles of the battery 10. Wherein controlling the operation of the step-down circuit 42 includes: the main switch tube Q7 is controlled to be turned on or off according to a preset duty ratio, so that the purpose of reducing the voltage of the direct current bus is achieved.
The control method of the motor controller can reduce the loss of the electric control system and improve the efficiency of the electric control system.
The motor controller, the control method thereof and the electric vehicle provided by the embodiment of the application are described in detail. Specific examples are applied to illustrate the motor controller, the control method thereof and the electric automobile according to the embodiments of the present application, and the description of the above embodiments is only for helping to understand the core ideas of the present application, and is not intended to limit the present application. It should be noted that it would be obvious to those skilled in the art that various changes and modifications can be made herein without departing from the spirit and principles of the invention, which should also fall within the scope of the appended claims.

Claims (21)

1. The utility model provides a motor controller, is applied to in the electric automobile, its connection is between battery and motor, its characterized in that: the motor controller includes:
the inverter circuit is connected between the direct current bus and the motor and used for converting direct current into alternating current so as to drive the motor to work;
the voltage reduction circuit is positioned at the front stage of the inverter circuit and connected between the battery and the direct current bus and used for reducing the voltage on the direct current bus; and
and the bypass circuit is positioned at the front stage of the inverter circuit and connected with the step-down circuit in parallel and is used for bypassing or enabling the step-down circuit according to different working modes.
2. The motor controller of claim 1, wherein: the motor controller is provided with a first working mode and a second working mode, wherein when the motor controller is in the first working mode, the bypass circuit is closed, and the bypass circuit bypasses the step-down circuit; when the motor controller is in the second working mode, the bypass circuit is disconnected, and the step-down circuit works.
3. The motor controller of claim 2, wherein: when the motor controller is in the first working mode, the direct current bus is provided with a first direct current bus voltage; and when the motor controller is in the second working mode, the direct current bus is provided with a second direct current bus voltage, wherein the first direct current bus voltage is greater than or equal to the second direct current bus voltage.
4. The motor controller of claim 1, wherein: the inverter circuit comprises a first capacitor and three parallel working bridge arms, wherein the first capacitor and the three working bridge arms are connected in parallel between the positive electrode end and the negative electrode end of the direct current bus.
5. The motor controller of claim 4, wherein: each working bridge arm of the three working bridge arms comprises two power switch tubes connected in series, and the midpoints of the three working bridge arms are used for outputting alternating current and connected to the motor.
6. The motor controller of claim 4, wherein: the step-down circuit comprises a main switching tube, a follow current tube, an inductor and a second capacitor, wherein the second capacitor is connected in parallel between the positive electrode and the negative electrode of the battery, the main switching tube and the follow current tube are connected in series and then connected in parallel between the positive electrode and the negative electrode of the battery, and the inductor is connected between a connection point between the main switching tube and the follow current tube and the positive electrode end of the direct current bus.
7. The motor controller of claim 6, wherein: the main switching tube comprises a SiC MOS switching tube.
8. The motor controller of claim 7, wherein: the main switching tube comprises a first NMOS switching tube, wherein a grid electrode of the first NMOS switching tube is used for being connected with a first driving circuit, a drain electrode of the first NMOS switching tube is connected with the positive electrode of the battery, and a source electrode of the first NMOS switching tube is connected with the continuous tube.
9. The motor controller of claim 6, wherein: the freewheel tube comprises a SiC MOS switch tube.
10. The motor controller of claim 9, wherein: the freewheel tube comprises a second NMOS switch tube, a grid electrode of the second NMOS switch tube is used for being connected with a second driving circuit, a drain electrode of the second NMOS switch tube is connected with the main switch tube, and a source electrode of the second NMOS switch tube is connected with the negative electrode of the battery.
11. The motor controller of claim 6, wherein: the freewheeling diode comprises a freewheeling diode, the positive electrode of the freewheeling diode is connected with the negative electrode of the battery, and the negative electrode of the freewheeling diode is connected with the main switching tube.
12. The motor controller of claim 11, wherein: the freewheeling diode includes a SiC diode.
13. The motor controller of claim 6, wherein: the first capacitor and the second capacitor are connected in parallel when the bypass circuit is closed.
14. The motor controller of claim 6, wherein: the bypass circuit comprises a switching tube and a driving circuit for driving the switching tube, the switching tube of the bypass circuit is provided with a control end, a first end and a second end, the control end of the switching tube is connected to the driving circuit, the first end is connected to the positive electrode of the battery, and the second end is connected to the positive electrode of the direct current bus.
15. The motor controller of claim 14, wherein: the switching tube in the bypass circuit comprises an IGBT or SiC MOS switching tube.
16. An electric automobile, characterized in that: comprising a motor controller according to any one of claims 1 to 15, a battery and a motor, the motor controller being connected between the battery and the motor.
17. The control method of the motor controller is applied to the electric automobile, and the motor controller is connected between a battery and a motor, and is characterized in that: the control method comprises the following steps:
when the first output requirement of the motor needs to be met, controlling the motor controller to work in a first working mode so that the direct current bus has a first direct current bus voltage; and
when the second output requirement of the motor needs to be met, controlling the motor controller to work in a second working mode so that the direct current bus is provided with a second direct current bus voltage, wherein the first direct current bus voltage is greater than or equal to the second direct current bus voltage.
18. The control method according to claim 17, characterized in that: the motor controller comprises an inverter circuit, a voltage reducing circuit and a bypass circuit, wherein the voltage reducing circuit and the bypass circuit are positioned at the front stage of the inverter circuit,
the controlling the motor controller to operate in the first working mode comprises: controlling the bypass circuit to be closed, wherein the bypass circuit bypasses the step-down circuit, and the bypass circuit is communicated with the battery and the loop of the inverter circuit;
the controlling the motor controller to operate in the second working mode includes: and controlling the bypass circuit to be disconnected and controlling the step-down circuit to work so as to reduce the voltage on the direct current bus.
19. The control method according to claim 18, characterized in that: the step-down circuit comprises a first switching tube and a second switching tube which are connected in parallel between the positive electrode and the negative electrode of the battery, wherein the step-down circuit is controlled to work and comprises:
the first switching tube and the second switching tube are controlled to be turned on and off according to a preset duty ratio, wherein when the first switching tube is controlled to be turned on, the second switching tube is controlled to be turned off; and when the first switching tube is controlled to be switched off, the second switching tube is controlled to be switched on.
20. The control method according to claim 18, characterized in that: the step-down circuit comprises a main switching tube and a freewheeling diode which are connected in parallel between the anode and the cathode of the battery, wherein the step-down circuit comprises:
the main switching tube is controlled to be turned on or off according to a predetermined duty ratio.
21. The control method according to claim 17, characterized in that: the first output demand includes a first torque and a first power demand, and the second output demand includes a second torque and a second power demand, wherein the first torque is greater than the second torque and the first power is greater than the second power.
CN202310041897.1A 2023-01-12 2023-01-12 Motor controller, control method thereof and electric automobile Pending CN116317714A (en)

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Publication number Priority date Publication date Assignee Title
US20160075241A1 (en) * 2014-09-11 2016-03-17 Gm Global Technology Operations Vehicle with selectively enabled boost converter
US10110103B1 (en) * 2017-06-21 2018-10-23 GM Global Technology Operations LLC Electric drive system enhancement using a DC-DC converter
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