Electric drive system and vehicle

Abstract

An electric drive system (10) and a vehicle comprising the electric drive system (10). The electric drive system (10) comprises a first electric drive subsystem (110) and a second electric drive subsystem (120), and the first electric drive subsystem (110) is configured to enter a corresponding safety state in a fault state on the basis of a control instruction received from the second electric drive subsystem (120), wherein the control instruction indicates motor rotating speed information, and the safety state comprises an ASC safety state and an SPO safety state.

Description

Electric drive systems and vehicles Technical Field

[0001] The present application relates to the field of motor control technology, and in particular, to an electric drive system and a vehicle including the electric drive system. Background Art

[0002] Electric vehicles are powered by a drive motor, which is controlled by an electric drive system, converting the battery's electrical energy into mechanical energy to achieve vehicle motion. Permanent magnetic synchronous motors (PMSMs) have become the mainstream drive system for pure electric vehicles due to their high efficiency, high output torque, high power density, and excellent dynamic performance.

[0003] As an electrical and electronic component, the electric drive system of an electric vehicle must comply with functional safety. In the event of a fault, the motor must be controlled to a safe state, meaning it will not damage the electric drive system itself or other equipment on the bus. The electric drive system of a permanent magnet synchronous motor has two safety states: the ASC (Active Short Circuit) safety state, which uses the power semiconductors in the electric drive system to short-circuit the motor windings; and the SPO (Safety Pulse Off) safety state, which shuts down all power semiconductors in the electric drive system and opens the motor windings. Although the electric drive system itself can enter the corresponding safe state, if a fault occurs in the electric drive system, these safety control operations cannot be implemented.

[0004] Summary of the Invention

[0005] In order to solve or at least alleviate one or more of the above problems, the following technical solutions are provided: Embodiments of the present application provide an electric drive system and a vehicle including the electric drive system, which can solve the safety issues caused by electric drive system failures of dual-drive vehicles.

[0006] According to a first aspect of the present application, an electric drive system is provided, comprising a first electric drive subsystem and a second electric drive subsystem, wherein the first electric drive subsystem is configured to enter a corresponding safe state in a fault state based on a control instruction received from the second electric drive subsystem, wherein the control instruction indicates motor speed information, and the safe state includes an ASC safe state and an SPO safe state.

[0007] As an alternative or supplement to the above scheme, in an electric drive system according to an embodiment of the present invention, the second electric drive subsystem is configured to: receive motor speed information; issue a first control instruction to control the first electric drive subsystem to enter the ASC safety state when the motor speed information indicates that the real-time speed of the motor is greater than or equal to a first threshold; issue a second control instruction to control the first electric drive subsystem to enter the SPO safety state when the motor speed information indicates that the real-time speed of the motor is less than the first threshold.

[0008] As an alternative or supplement to the above solution, in an electric drive system according to an embodiment of the present invention, the second electric drive subsystem is configured to enter a corresponding safe state based on a control instruction received from the first electric drive subsystem in a fault state.

[0009] As an alternative or supplement to the above scheme, in an electric drive system according to an embodiment of the present invention, the first electric drive subsystem is configured to: receive motor speed information; issue a third control instruction to control the second electric drive subsystem to enter the ASC safety state when the motor speed information indicates that the real-time speed of the motor is greater than or equal to a first threshold; and issue a fourth control instruction to control the second electric drive subsystem to enter the SPO safety state when the motor speed information indicates that the real-time speed of the motor is less than the first threshold.

[0010] As an alternative or supplement to the above scheme, in an electric drive system according to one embodiment of the present invention, the control instruction is a PWM signal, and the first control instruction or the third control instruction issued when the real-time speed of the motor is greater than or equal to the first threshold is a first PWM signal having a first frequency and a first duty cycle, and the second control instruction or the fourth control instruction issued when the real-time speed of the motor is less than the first threshold is a second PWM signal having the first frequency and the second duty cycle, wherein the sum of the first duty cycle and the second duty cycle is 1.

[0011] As an alternative or supplement to the above solution, in an electric drive system according to an embodiment of the present invention, the electric drive system also includes a speed identification circuit, which is configured to convert the control instruction into a high level for indicating a high motor speed or a low level for indicating a low motor speed.

[0012] As an alternative or supplement to the above scheme, in an electric drive system according to an embodiment of the present invention, the speed identification circuit includes: a voltage stabilizing circuit including a voltage stabilizing diode and a transistor, the voltage stabilizing diode being connected to the base of the transistor to raise the conduction voltage of the transistor; a second-order RC filter circuit for converting the control instruction adjusted by the voltage stabilizing circuit into a fixed level; and a comparison circuit for comparing the fixed level with a reference level to output the high level or the low level.

[0013] As an alternative or supplement to the above solution, in an electric drive system according to an embodiment of the present invention, the speed identification circuit further includes: a hysteresis circuit for feeding back the output of the comparison circuit to the positive input port of the comparison circuit through a resistor.

[0014] As an alternative or supplement to the above solution, in an electric drive system according to an embodiment of the present invention, the first electric drive subsystem is a rear-wheel drive control system of a dual-wheel drive vehicle, and the second electric drive subsystem is a front-wheel drive control system of the dual-wheel drive vehicle.

[0015] According to a second aspect of the present application, a vehicle is provided, which includes any one of the electric drive systems described according to the first aspect of the present application.

[0016] According to one or more embodiments of the present application, the dual electric drive subsystem solution can enter a corresponding safe state based on the control instructions received from the other electric drive subsystem when one of the electric drive subsystems fails, thereby avoiding safety issues caused by electric drive system failures. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and other objects and advantages of the present application will become more fully apparent from the following detailed description taken in conjunction with the accompanying drawings, wherein the same or similar elements are denoted by the same reference numerals.

[0018] FIG1 shows a schematic block diagram of an electric drive system 10 according to one or more embodiments of the present application; and

[0019] FIG2 shows a schematic circuit diagram of an electric drive system 20 according to one or more embodiments of the present application. DETAILED DESCRIPTION

[0020] The description of the following specific embodiments is merely exemplary in nature and is not intended to limit the disclosed technology or the application and use of the disclosed technology. In addition, there is no intention to be bound by any express or implied theory presented in the foregoing technical field, background technology or the following specific embodiments.

[0021] Terms such as "comprising" and "including" indicate that in addition to the units and steps directly and explicitly stated in the specification, the technical solution of the present invention does not exclude the situation where there are other units and steps that are not directly or explicitly stated. Terms such as "first" and "second" do not indicate the order of units in terms of time, space, size, etc., but are only used to distinguish between the units. It should be understood that the technology disclosed in the present invention is generally used in electric vehicles, which include but are not limited to pure electric vehicles (BEVs), hybrid electric vehicles (HEVs), fuel cell vehicles (FCEVs), etc.

[0022] Hereinafter, various exemplary embodiments according to the present application will be described in detail with reference to the accompanying drawings.

[0023] Reference is now made to FIG1 , which shows a schematic block diagram of an electric drive system 10 according to one or more embodiments of the present application.

[0024] As shown in Figure 1, the electric drive system 10 includes two subsystems, namely a first electric drive subsystem 110 and a second electric drive subsystem 120. Exemplarily, the electric drive system 10 is the electric drive system of a dual-drive electric vehicle, with the first electric drive subsystem 110 being the rear-drive control system of the dual-drive vehicle, and the second electric drive subsystem 120 being the front-drive control system of the dual-drive vehicle. It is understood that a vehicle's electric drive system typically includes a motor, a motor controller, and a transmission mechanism. As an electronic and electrical component, the electric drive system of an electric vehicle must comply with functional safety. In the event of a fault, the motor can be controlled to a safe state to ensure personal safety.

[0025] Normally, when the motor speed is low, jitter will occur when entering the ASC safety state. Therefore, when the motor speed is low, it is expected to enter the SPO safety state; when the motor speed is high, it is expected to enter the ASC safety state. Generally speaking, the vehicle's electric drive system (for example, the electric drive system 10, the first electric drive subsystem 110, the second electric drive subsystem 120) itself can detect the motor speed to enter and switch to the safe state, but if the electric drive system fails, it will not be able to perform speed detection and operations such as entering and switching to the safe state.

[0026] In this regard, some embodiments of the present application propose, based on a dual-drive system, that a control instruction representing motor speed information is sent to the rear-drive control system (or front-drive control system) through the front-drive control system (or rear-drive control system). At this time, even if the rear-drive control system (or front-drive control system) fails, it can enter and switch to a safe state according to the control instruction issued by the front-drive control system (or rear-drive control system).

[0027] Optionally, in the embodiment shown in Figure 1, the second electric drive subsystem 120 is configured to: receive motor speed information; issue a first control instruction to control the first electric drive subsystem 110 to enter the ASC safety state when the motor speed information indicates that the real-time motor speed is greater than or equal to a first threshold (for example, 8000 rpm); issue a second control instruction to control the first electric drive subsystem 110 to enter the SPO safety state when the motor speed information indicates that the real-time motor speed is less than the first threshold. The first electric drive subsystem 110 is configured to enter a corresponding safety state (for example, ASC safety state, SPO safety state) based on the control instruction (for example, first control instruction, second control instruction) received from the second electric drive subsystem 120 in a fault state. In some embodiments according to the present application, regardless of whether the first electric drive subsystem 110 is faulty or not, the second electric drive subsystem 120 continues to receive motor speed information and issues control instructions to the first electric drive subsystem 110. The first electric drive subsystem 110 switches to a safe state only in a fault state according to the control instruction issued by the second electric drive subsystem 120. In some other embodiments of the present application, the second electric drive subsystem 120 issues a control instruction to the first electric drive subsystem 110 only when the first electric drive subsystem 110 is in a fault state.

[0028] Optionally, the first electric drive subsystem 110 is configured to: receive motor speed information; issue a third control instruction when the motor speed information indicates that the real-time speed of the motor is greater than or equal to a first threshold (e.g., 8000 rpm) to control the second electric drive subsystem 120 to enter the ASC safety state; and issue a fourth control instruction when the motor speed information indicates that the real-time speed of the motor is less than the first threshold to control the second electric drive subsystem 120 to enter the SPO safety state. The second electric drive subsystem 120 is configured to enter a corresponding safety state (e.g., ASC safety state, SPO safety state) based on the control instruction (e.g., third control instruction, fourth control instruction) received from the first electric drive subsystem 110 in a fault state. In some embodiments of the present application, regardless of whether the second electric drive subsystem 120 is faulty or not, the first electric drive subsystem 110 continues to receive motor speed information and issues control instructions to the second electric drive subsystem 120. The second electric drive subsystem 120 switches to a safe state only in a fault state according to the control instruction issued by the first electric drive subsystem 110. In some other embodiments of the present application, the first electric drive subsystem 110 issues a control instruction to the second electric drive subsystem 120 only when the second electric drive subsystem 120 is in a fault state.

[0029] Optionally, in order to ensure strong anti-interference performance of signal transmission, the control instructions (e.g., the first control instruction, the second control instruction, the third control instruction, the fourth control instruction) issued by the first electric drive subsystem 110 or the second electric drive subsystem 120 are pulse width modulation (PWM) signals. Specifically, when the real-time speed of the motor is greater than or equal to the first threshold, the first control instruction issued by the second electric drive subsystem 120 or the third control instruction issued by the first electric drive subsystem 110 is a first PWM signal having a first frequency and a first duty cycle. When the real-time speed of the motor is less than the first threshold, the second control instruction issued by the second electric drive subsystem 120 or the fourth control instruction issued by the first electric drive subsystem 110 is a second PWM signal having a first frequency and a second duty cycle, wherein the sum of the first duty cycle and the second duty cycle is 1, that is, the first PWM signal and the second PWM signal are complementary signals. It can be understood that the anti-interference performance of the complementary PWM signal is better than that of the non-complementary PWM signal, thereby improving the stability and reliability of the system. For example, when the real-time speed of the motor is greater than or equal to 8000 rpm, the first electric drive subsystem 110 and / or the second electric drive subsystem 120 sends a PWM signal with a frequency of 1 kHz and an 80% duty cycle. When the real-time speed of the motor is less than 8000 rpm, the first electric drive subsystem 110 and / or the second electric drive subsystem 120 sends a PWM signal with a frequency of 1 kHz and a 20% duty cycle. If the first electric drive subsystem 110 and / or the second electric drive subsystem 120 receives a PWM signal with a frequency of 1 kHz and an 80% duty cycle, it enters the ASC safety state. If the first electric drive subsystem 110 and / or the second electric drive subsystem 120 receives a PWM signal with a frequency of 1 kHz and a 20% duty cycle, it enters the SPO safety state.

[0030] Optionally, after the PWM signal is transmitted to the first electric drive subsystem 110 and / or the second electric drive subsystem 120, it can be converted into high or low levels through the speed identification circuit to indicate high or low speed information. Specifically, the electric drive system 10 also includes a speed identification circuit 130, which is configured to convert a control instruction (e.g., a first control instruction, a second control instruction, a third control instruction, a fourth control instruction) into a high level indicating a high motor speed (e.g., the real-time speed of the motor is greater than or equal to a first threshold) or a low level indicating a low motor speed (e.g., the real-time speed of the motor is less than the first threshold). Optionally, the speed identification circuit 130 can be part of the first electric drive subsystem 110 and / or the second electric drive subsystem 120,

[0031] Optionally, the rotation speed identification circuit 130 includes one or more of a voltage stabilization circuit, a second-order RC filter circuit, a comparison circuit, and a hysteresis circuit.

[0032] In some embodiments according to the present application, a voltage stabilizing circuit is used to provide a stable and reliable input voltage for subsequent speed identification. The voltage stabilizing circuit includes a voltage stabilizing tube (e.g., a Zener diode) and a transistor, wherein one end of the voltage stabilizing tube is used to receive a control instruction (e.g., a PWM signal) from the first electric drive subsystem 110 or the second electric drive subsystem 120, and the other end of the voltage stabilizing tube is connected to the base of the transistor. It should be noted that the conduction voltage of the transistor is usually very small, so the presence of the voltage stabilizing tube is very necessary. The transistor will only be turned on when the voltage stabilizing tube is broken down and reaches a certain voltage value, that is, the presence of the voltage stabilizing tube raises the conduction voltage of the transistor, thereby preventing the transistor from being mis-conducted and improving the reliability of the system.

[0033] In some embodiments of the present application, a second-order RC filter circuit is used to convert control instructions regulated by a voltage stabilization circuit into a fixed voltage level. The second-order RC filter circuit is composed of two first-order RC filter circuits connected in series. The control instructions regulated by the voltage stabilization circuit (e.g., PWM signals) are converted into a fixed voltage level through the RC filter circuit composed of resistors and capacitors.

[0034] In some embodiments of the present application, a comparison circuit is configured to compare a fixed level output by a second-order RC filter circuit with a reference level to output a high level or a low level. For example, the filtered fixed level can be input to a non-inverting input of the comparator via a resistor, and a fixed reference voltage is given to an inverting input of the comparator. The output of the comparator can be connected to a power supply via a resistor. In this case, if the filtered fixed level is greater than the reference voltage, the comparator outputs a high level; if the filtered fixed level is less than the reference voltage, the comparator outputs a low level. The high or low level of the output indicates whether the motor speed is greater than the first threshold.

[0035] It should be noted that, in some embodiments of the present application, when the control instruction issued by the first electric drive subsystem 110 or the second electric drive subsystem 120 changes due to a change in the motor speed (for example, the duty cycle of the PWM signal changes), the generated ripple will cause the comparator to output an incorrect signal. In response to this, the electric drive system according to some embodiments of the present application adds a hysteresis circuit to ensure the accuracy of the high and low levels output by the comparator when the control instruction is switched. Optionally, the speed identification circuit 130 may include a hysteresis circuit for feeding back the output of the comparison circuit to the positive input port of the comparison circuit through a resistor.

[0036] Continuing to refer to FIG. 2 , FIG. 2 shows a schematic circuit diagram of an electric drive system 20 according to one or more embodiments of the present application.

[0037] As shown in Figure 2, the front-drive control system of electric drive system 20 issues a PWM control command based on the motor speed. This PWM control command is input to the base of transistor Q1. The vehicle battery KL30 is connected to the collector of transistor Q1 via resistor R1, and the emitter of transistor Q1 is grounded. This front-drive control system is pulled up to KL30 via transistor Q1 and resistor R1 to improve the driving capability and anti-interference ability of the PWM control command.

[0038] After receiving the command, the rear-wheel drive control system can use the speed recognition circuit to convert it into high or low levels to indicate high or low speed information. As shown in Figure 2, the speed recognition circuit includes a voltage-stabilizing circuit composed of capacitor C1, voltage-stabilizing diode D1, transistor Q2, and resistor R5. One end of the voltage-stabilizing diode D1 receives the command from the front-wheel drive control system, and the other end of the voltage-stabilizing diode D1 is connected to the base of the transistor Q2. The power supply VDD1 is connected to the collector of the transistor Q2 through the resistor R5. The power supply VDD1 needs to be powered by the high-voltage battery to prevent the circuit from malfunctioning in the event of a low-voltage power outage or a control system failure. As mentioned above, the voltage-stabilizing diode D1 is mainly used to raise the conduction voltage of the transistor Q2 to prevent the transistor Q2 from being turned on by mistake.

[0039] The control command, regulated by the voltage regulator circuit, is input into a second-order RC filter circuit consisting of resistors R6 and R7 and capacitors C2 and C3, which converts it into a fixed voltage level. The fixed voltage output from the second-order RC filter circuit is then input into a comparator circuit and a hysteresis circuit. Specifically, the filtered fixed voltage level is fed to the non-inverting input of comparator U1 via resistor R8. The inverting input of comparator U1 is divided down to a fixed reference voltage using resistors R10 and R11. The output of comparator U1 is pulled up to VDD1 via resistor R12 and fed back to the non-inverting input of comparator U1 via resistor R9, forming a hysteresis circuit. This prevents ripple generated when switching between PWM control commands with different duty cycles from causing comparator U1 to output an incorrect signal. If the filtered fixed voltage level is greater than the reference voltage, comparator U1 outputs a high level; if the filtered fixed voltage level is less than the reference voltage, comparator U1 outputs a low level. Finally, the output of comparator U1 is fed into the safety logic circuit of the rear-wheel drive control system to generate a safety output signal used to control the motor to enter a corresponding safe state.

[0040] The above-mentioned electric drive systems 10 and 20 can enter a corresponding safe state based on the control instructions received from another electric drive subsystem (for example, the second electric drive subsystem 120 or the first electric drive subsystem 110 in Figure 1, the front drive control system in Figure 2) when one of the electric drive subsystems (for example, the first electric drive subsystem 110 or the second electric drive subsystem 120 in Figure 1, the rear drive control system in Figure 2) fails, thereby avoiding safety problems caused by the failure of the electric drive system.

[0041] According to another aspect of the present application, a vehicle is provided, comprising any one of the electric drive systems described above.

[0042] The embodiments and examples set forth herein are provided to best illustrate embodiments according to the present invention and its specific applications, and thereby enable those skilled in the art to make and use the invention. However, those skilled in the art will appreciate that the above description and examples are provided for ease of illustration and example only. The descriptions set forth are not intended to encompass all aspects of the invention or to limit the invention to the precise forms disclosed.

Claims

1. An electric drive system, characterized in that: The electric drive system includes a first electric drive subsystem and a second electric drive subsystem, wherein: The first electric drive subsystem is configured to enter a corresponding safety state in a fault state based on a control instruction received from the second electric drive subsystem, wherein the control instruction indicates motor speed information, and the safety state includes an ASC safety state and an SPO safety state.

2. The electric drive system according to claim 1, wherein: The second electric drive subsystem is configured as follows: Receive motor speed information; When the motor speed information indicates that the real-time motor speed is greater than or equal to a first threshold, issuing a first control instruction to control the first electric drive subsystem to enter an ASC safety state; When the motor speed information indicates that the real-time motor speed is less than a first threshold, a second control instruction is issued to control the first electric drive subsystem to enter an SPO safety state.

3. The electric drive system according to claim 1, wherein: The second electric drive subsystem is configured to enter a corresponding safety state based on a control instruction received from the first electric drive subsystem in a fault state.

4. The electric drive system according to claim 1, wherein: The first electric drive subsystem is configured as follows: Receive motor speed information; When the motor speed information indicates that the real-time motor speed is greater than or equal to a first threshold, issuing a third control instruction to control the second electric drive subsystem to enter an ASC safety state; When the motor speed information indicates that the real-time motor speed is less than the first threshold, a fourth control instruction is issued to control the second electric drive subsystem to enter the SPO safety state.

5. The electric drive system according to any one of claims 1 to 4, wherein: The control instruction is a PWM signal, and the first control instruction or the third control instruction issued when the real-time speed of the motor is greater than or equal to a first threshold is a first PWM signal with a first frequency and a first duty cycle, and the second control instruction or the fourth control instruction issued when the real-time speed of the motor is less than the first threshold is a second PWM signal with the first frequency and a second duty cycle, wherein the sum of the first duty cycle and the second duty cycle is 1.

6. The electric drive system according to claim 5, wherein: The electric drive system further includes a rotation speed identification circuit configured to convert the control instruction into a high level indicating a high motor rotation speed or a low level indicating a low motor rotation speed.

7. The electric drive system according to claim 6, wherein: The speed identification circuit comprises: A voltage stabilizing circuit comprising a voltage stabilizing tube and a triode, wherein the voltage stabilizing tube is connected to the base of the triode to raise the conduction voltage of the triode; A second-order RC filter circuit for converting the control instruction regulated by the voltage stabilization circuit into a fixed level; and A comparison circuit is used for comparing the fixed level with a reference level to output the high level or the low level.

8. The electric drive system according to claim 7, wherein: The speed identification circuit also includes: A hysteresis circuit is used to feed back the output of the comparison circuit to the positive input port of the comparison circuit through a resistor.

9. The electric drive system according to any one of claims 1 to 4, wherein: The first electric drive subsystem is a rear-wheel drive control system of a two-wheel drive vehicle, and the second electric drive subsystem is a front-wheel drive control system of the two-wheel drive vehicle.

10. A vehicle, characterized in that: Comprising the electric drive system as described in any one of claims 1-9.

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