An electric power steering system and vehicle

Abstract

The application discloses an electric power steering system and a vehicle, and relates to the technical field of vehicles, which comprises a controller, a three-phase motor, a main phase line breaker, a main drive bridge, a backup phase line breaker and a backup drive bridge; the input end of the main drive bridge is used for being connected with a main power supply; the input end of the main phase line breaker is connected with the output end of the main drive bridge, and the output end of the main phase line breaker is used for being connected with a first partial winding of each phase of the three-phase motor; the input end of the backup drive bridge is used for being connected with a backup power supply; the input end of the backup phase line breaker is used for being connected with the output end of the backup drive bridge, and the output end of the backup phase line breaker is connected with a second partial winding of each phase of the three-phase motor; the access proportion of the first partial winding is greater than or equal to the access proportion of the second partial winding; and the controller is used for controlling the main phase line breaker to be disconnected and the backup phase line breaker to be closed when a main control loop fails. The system can still provide 100% assistance after a single point failure of one sub-EPS.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, and in particular to an electric power steering system and a vehicle. Background Technology

[0002] Electric power steering (EPS) systems are now widely used in automobiles. As the core component of EPS, the safety and reliability of the steering motor directly determines whether electric power steering can be provided normally. With the improvement of vehicle safety levels and the development of autonomous driving, redundant design of the steering motor is essential.

[0003] Currently, the design methods for redundant motors mainly include the following two:

[0004] One relatively simple method is dual-motor control, where each motor has an independent controller and power supply, which is equivalent to one EPS including two sub-EPS. When a single point of failure occurs in one sub-EPS, it immediately switches to the other EPS. Although this method can solve some problems, it has drawbacks such as high cost, large space occupation, and difficulty in vehicle layout.

[0005] Another method is to use a multi-phase motor (such as a 6-phase motor) and a corresponding redundant controller, such as... Figure 1 As shown, the explanation uses a 6-phase (dual three-phase) control loop as an example. Figure 1 As shown, the system includes a power supply, sensors, control chip, and drive bridge. When a single point of failure occurs in the control loop, the controller shuts off the assist for that loop. At this time, the sub-EPS system can only provide 50% of its maximum assist capacity. This design has obvious defects and shortcomings; when a single point of failure occurs in a control loop, the EPS assist will be significantly reduced, posing a safety hazard. Summary of the Invention

[0006] To address the aforementioned technical problems, this application provides an electric power steering system and vehicle that can still provide 100% power assistance after a single point of failure occurs in a sub-EPS.

[0007] The embodiments of this application disclose the following technical solutions:

[0008] In a first aspect, this application provides an electric power steering system, comprising: a controller, a three-phase motor, a main phase line circuit breaker, a main drive axle, a backup phase line circuit breaker, and a backup drive axle;

[0009] The input terminal of the main drive bridge is used to connect to the main power supply;

[0010] The input end of the main phase breaker is connected with the output end of the main drive bridge, and the output end of the main phase breaker is connected with the first partial winding of each phase of the three-phase motor;

[0011] The input end of the backup drive bridge is connected with a backup power supply;

[0012] The input end of the backup phase breaker is connected with the output end of the backup drive bridge, and the output end of the backup phase breaker is connected with the second partial winding of each phase of the three-phase motor;

[0013] The access ratio of the first partial winding is greater than or equal to the access ratio of the second partial winding.

[0014] The controller is configured to control the main phase breaker to be opened and the backup phase breaker to be closed when the main control loop fails.

[0015] Optionally, the controller is configured to control the main phase breaker to be closed and the backup phase breaker to be opened when the main control loop does not fail.

[0016] Optionally, the main phase breaker comprises a first switch tube, a second switch tube and a third switch tube, and the backup phase breaker comprises a fourth switch tube, a fifth switch tube and a sixth switch tube.

[0017] The first switch tube is connected with the first partial winding of the first phase of the three-phase motor, the second switch tube is connected with the first partial winding of the second phase of the three-phase motor, and the third switch tube is connected with the first partial winding of the third phase of the three-phase motor.

[0018] The fourth switch tube is connected with the second partial winding of the first phase of the three-phase motor, the fifth switch tube is connected with the second partial winding of the second phase of the three-phase motor, and the sixth switch tube is connected with the second partial winding of the third phase of the three-phase motor.

[0019] The controller is specifically configured to control the first switch tube, the second switch tube and the third switch tube to be opened and the fourth switch tube, the fifth switch tube and the sixth switch tube to be closed when the main control loop fails.

[0020] Optionally, each phase of the three-phase motor comprises n windings, the access ratio of the first partial winding is 1, and the access ratio of the second partial winding is (n-m) / n, where n and m are positive integers.

[0021] Optionally, (n-m) / n is greater than or equal to 0.6.

[0022] Optionally, n is any value in the range of 4-6.

[0023] Optionally, when n=4, m=1; when n=5, m=1 or 2, when n=6, m=1 or 2.

[0024] Optionally, the design power of the standby control loop including the standby phase line breaker and the standby drive bridge is n / (n-m) times of the system demand power.

[0025] Optionally, the main control loop failure includes at least one of the following failures:

[0026] The main power supply, the main power supply chip, the filter circuit, the main chip, the main transceiver circuit, the first main pre-drive chip, the second main pre-drive chip, the main drive bridge, the main phase line breaker, the main motor position sensor, and the main torque sensor.

[0027] In a second aspect, the application provides a vehicle comprising the electric power assisted steering system according to any one of the first aspect.

[0028] From the above technical solution, the application has the following advantages:

[0029] The electric power assisted steering system provided by the application comprises a controller, a three-phase motor, a main phase line breaker, a main drive bridge, a standby phase line breaker and a standby drive bridge. The input end of the main drive bridge is connected with a main power supply. The input end of the main phase line breaker is connected with the output end of the main drive bridge. The output end of the main phase line breaker is connected with a first part winding of each phase of the three-phase motor. The input end of the standby drive bridge is connected with a standby power supply. The input end of the standby phase line breaker is connected with the output end of the standby drive bridge. The output end of the standby phase line breaker is connected with a second part winding of each phase of the three-phase motor. The access ratio of the first part winding is greater than or equal to the access ratio of the second part winding. The controller is used to control the main phase line breaker to be disconnected and the standby phase line breaker to be closed when the main control loop fails. Therefore, when a single point failure occurs in the main control loop (for example, a main sub-EPS system), the main control loop is cut off from the EPS system by disconnecting the main phase line breaker, and the standby control loop provides the assist force for steering. Since the access ratio of the first part winding is greater than or equal to the access ratio of the second part winding, the assist force provided by the standby control loop is greater than or equal to the assist force provided by the main control loop. Therefore, even if a single point failure occurs, the electric power assisted steering system provided by the application can provide 100% assist force. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0031] Figure 1 A schematic diagram of a redundant EPS topology in the prior art;

[0032] Figure 2 A schematic diagram of an EPS topology provided by the present application;

[0033] Figure 3 A schematic diagram of a drive circuit provided by the present application;

[0034] Figure 4 A schematic diagram of another drive circuit provided by the present application;

[0035] Figure 5 A schematic diagram of still another drive circuit provided by the present application. DETAILED DESCRIPTION

[0036] At present, although the winding insulation fault has a certain proportion in the theoretical research of the EPS motor, especially the three-phase EPS motor or the brushless direct current motor, the winding fault does not appear in the after-sales problem list. The manufacturing process and automatic equipment of the EPS motor now make up for the defect of the winding fault in the theoretical research. Therefore, listing the winding as a potential failure point is over-design and waste.

[0037] Based on this, the embodiments of the present application provide an electric power steering system, which takes the premise that the EPS motor does not fail, such as the winding of the EPS motor does not fail. Referring to Figure 2 , which is a schematic diagram of an electric power steering system provided by the embodiments of the present application. The electric power steering system comprises a controller (not shown), a three-phase motor, a main phase line circuit breaker, a main drive bridge, a backup phase line circuit breaker and a backup drive bridge.

[0038] The input end of the main drive bridge is used to be connected with a main power supply; the input end of the main phase line circuit breaker is used to be connected with the output end of the main drive bridge, and the output end of the main phase line circuit breaker is used to be connected with the first part winding of each phase of the three-phase motor.

[0039] The input end of the backup drive bridge is used to be connected with a backup power supply; the input end of the backup phase line breaker is used to be connected with the output end of the backup drive bridge, and the output end of the backup phase line breaker is used to be connected with the second partial winding of each phase of the three-phase motor. In some embodiments, the main power supply and the backup power supply can be the same power supply, so as to reduce the cost of the redundant setting.

[0040] The access ratio of the first partial winding is greater than or equal to the access ratio of the second partial winding; and the controller is configured to control the main phase line breaker to be opened and the backup phase line breaker to be closed when the main control loop fails.

[0041] In some embodiments, each phase of the three-phase motor includes n windings, the access ratio of the first partial winding is 1, and the access ratio of the second partial winding is (n-m) / n, where n and m are positive integers, and m < n. In some embodiments, (n-m) / n is greater than or equal to 0.6.

[0042] It should be noted that (n-m) / n is greater than or equal to 0.6 is only an example, and (n-m) / n can be greater than or equal to other values, such as 0.7.

[0043] In some examples, n can be any value from 4 to 6, for example, when n = 4, m = 1; when n = 5, m = 1 or 2, and when n = 6, m = 1 or 2. Accordingly, the design power of the backup control loop including the backup phase line breaker and the backup drive bridge is n / (n-m) times the system demand power.

[0044] In some embodiments, the controller is configured to control the main phase line breaker to be closed and the backup phase line breaker to be opened when the main control loop does not fail.

[0045] Continuing to refer to Figure 2 The electronic power steering system can further include a main filter circuit, a main power supply chip, a first main pre-drive chip, a second main pre-drive chip, a main transceiver circuit, a main motor position sensor, a main torque sensor, and a main chip. Similarly, the electronic power steering system can further include a backup filter circuit, a backup power supply chip, a first backup pre-drive chip, a second backup pre-drive chip, a backup transceiver circuit, a backup motor position sensor, a backup torque sensor, and a backup chip.

[0046] The main control loop failure can be at least one of the following failures: a main power supply, a main power supply chip, a filter circuit, a main chip, a main transceiver circuit, a first main pre-drive chip, a second main pre-drive chip, a main drive bridge, a main phase line breaker, a main motor position sensor, and a main torque sensor.

[0047] For ease of understanding, the following refers to Figure 3This figure is a schematic diagram of a driving circuit provided in an embodiment of this application. Figure 3 As shown, the main phase circuit breaker includes a first switching transistor QF. 11 Second switching transistor QF 21 and the third switching transistor QF 31 The backup phase circuit breaker includes a fourth switching transistor QF. 32 Fifth switching transistor QF 12 and the sixth switch QF 22 .

[0048] The first switching transistor is connected to the first part of the winding of the first phase (e.g., phase C) of the three-phase motor, the second switching transistor is connected to the first part of the winding of the second phase (e.g., phase A) of the three-phase motor, and the third switching transistor is connected to the first part of the winding of the third phase (e.g., phase B) of the three-phase motor.

[0049] The fourth switch is connected to the second part of the winding of the first phase of the three-phase motor, the fifth switch is connected to the second part of the winding of the second phase of the three-phase motor, and the sixth switch is connected to the second part of the winding of the third phase of the three-phase motor.

[0050] like Figure 3 As shown, each phase of a three-phase motor includes four windings, namely: L a1 L b1 L c1 L a2 L b2 L c2 L a3 L b3 L c3 L a4 L b4 L c4 The first part of the windings has an access ratio of 1, meaning all 12 windings are connected. The second part of the windings has an access ratio of 3 / 4, with 3 windings connected to each phase. For example, if L is connected... a2 L b2 L c2 L a3 L b3 L c3 L a4 L b4 L c4 Among them, winding L a1 And with L a2 L a3 L a4 Series connection, winding L b1 With L b2 L b3 L b4 Series connection, winding Lc1 With L c2 L c3 L c4 Series connection. For phase A, the first winding includes L... a1 L a2 L a3 and L a4 The second winding includes L a2 L a3 and L a4 The others are similar.

[0051] Specifically, the controller is used to control the first switch, the second switch, and the third switch to disconnect and the fourth switch, the fifth switch, and the sixth switch to close when the main control circuit fails.

[0052] The main drive bridge comprises six power devices: VT11, VT21, VT31, VT41, VT51, and VT61; similarly, the backup drive bridge comprises six power devices: VT12, VT22, VT32, VT42, VT52, and VT62. The main drive bridge and main power supply U... d1 A filter capacitor C is connected in parallel between them. d1 Similarly, in the backup drive bridge and backup power supply U d2 A filter capacitor C is connected in parallel between them. d2 .

[0053] For ease of understanding, the working principle of the controller provided in the embodiments of this application will be described below.

[0054] S1. When no fault occurs (e.g., normal state), via Figure 2 The main control circuit can provide 100% steering assist, and the backup control circuit is in standby mode. At this time, the QF in the drive circuit... 12 QF 22 and QF 32 No conduction. The backup chip in the backup control circuit and the main chip in the main control circuit still communicate and exchange information. In this case, the maximum motor current does not exceed 0.75 times the rated current.

[0055] S2. When a fault occurs, i.e. a fault occurs in the main control circuit, the power steering switching is initiated. Taking the main control circuit as an example, if any of the following devices fails: main power supply, main power chip, filter circuit, main chip, main transceiver circuit, first main pre-drive chip, second main pre-drive chip, main drive axle, main phase line circuit breaker, main motor position sensor, or main torque sensor, the main chip will transmit the fault information to the backup chip. The backup chip will then enable the backup control circuit. At this time, the nine windings can provide up to 3 / 4 of the design power (4 / 3 times the system demand power), still providing 100% power steering assistance.

[0056] The following describes different fault examples respectively:

[0057] Example 1: The main power supply fails to provide voltage, at this time, no current passes through the main control loop, the main chip stops working, and the main chip and the backup chip lose communication. According to the fault handling mechanism, the main control loop is automatically closed, the backup chip undertakes the tasks of calculation, processing and motor control, the backup control loop starts working, and the EPS can provide 100% of the maximum assistance demand.

[0058] When the main power supply fails to provide voltage, QF 11 , QF 21 , QF 31 and VT11, VT21, VT31, VT41, VT51 and VT61 in the main drive bridge (hereinafter referred to as the main drive bridge) cannot be turned on, which prevents U d2 from forming a short circuit with the ground in the main control loop through L a1 , L b1 and L c1 , thereby ensuring that the backup control loop works normally.

[0059] Example 2: The main power supply chip fails to provide stable voltage or no voltage, at this time, the current in the main control loop is unstable or no current, the main chip cannot work normally, and the backup chip cannot communicate normally. According to the fault handling mechanism, the main control loop is automatically closed, the backup chip undertakes the tasks of calculation, processing and motor control, the backup control loop starts working, and the EPS can provide 100% of the maximum assistance demand.

[0060] After the main control loop is closed, QF 11 , QF 21 , QF 31 and the main drive bridge cannot be turned on, which prevents U d2 from forming a short circuit with the ground in the main control loop through L a1 , L b1 and L c1 , thereby ensuring that the backup control loop works normally.

[0061] Example 3: The main filter circuit fails, which is manifested as short circuiting or open circuiting of the capacitor or / and the inductor. When the inductor is open-circuited or the capacitor is short-circuited, no current passes through the main control loop, the main chip stops working, and the backup chip cannot communicate normally. According to the fault handling mechanism, the backup chip undertakes the tasks of calculation, processing and motor control, the backup control loop starts working, and the EPS can provide 100% of the maximum assistance demand.

[0062] After the main control loop is automatically closed, QF 11 , QF 21 , QF 31and the main drive bridge cannot be turned on, preventing the standby control circuit from working when U d2 through L a1 , L b1 and L c1 and the ground in the main control circuit form a short circuit, thereby ensuring that the standby control circuit works normally.

[0063] Example 4: The main chip fails to undertake the tasks of calculation, processing and motor control. Since the selected chip meets the functional safety ASIL D, when it fails, no unintended assistance will occur, which means that when it fails, the main control circuit can be closed. The standby chip takes the place of the main chip to work, so that the standby control circuit starts to work, and the EPS can provide 100% of the maximum assistance demand.

[0064] When the main control circuit is closed, QF 11 , QF 21 , QF 31 and the main drive bridge cannot be turned on, preventing the standby control circuit from working when U d2 through L a1 , L b1 and L c1 and the ground in the main control circuit form a short circuit, thereby ensuring that the standby control circuit works normally.

[0065] Example 5: When the main transceiver circuit fails, the main chip cannot transmit and receive signals with CAN1. At this time, the EPS cannot receive signals such as vehicle speed sent by other nodes for calculation assistance, nor can it send signals such as EPS status to other nodes for their use. According to the fault handling mechanism, the main control circuit is closed, and the standby control circuit starts to work, and the EPS can provide 100% of the maximum assistance demand.

[0066] When the main control circuit is closed, QF 11 , QF 21 , QF 31 and the main drive bridge cannot be turned on, preventing the standby control circuit from working when U d2 through L a1 , L b1 and L c1 and the ground in the main control circuit form a short circuit, thereby ensuring that the standby control circuit works normally.

[0067] Example 6: The first main pre-drive chip fails to drive the conduction and disconnection of the MOS in the motor drive bridge, and cannot generate current in the motor winding to provide assistance. According to the fault handling mechanism, the main control circuit is closed, and the standby control circuit starts to work, and the EPS can provide 100% of the maximum assistance demand.

[0068] When the main control circuit is closed, QF 11 , QF 21 , QF31 and the main drive bridge cannot be turned on, preventing the backup control circuit from working when U d2 through L a1 , L b1 and L c1 and the ground in the main control circuit form a short circuit, thereby ensuring that the backup control circuit works normally.

[0069] Example 7: The second main pre-drive chip fails to drive the main phase breaker, causing the phase breaker to not turn on (in one ignition cycle, the device is in a constant on state), at which time the current of the MOS in the motor drive bridge cannot pass through the phase breaker to reach the motor winding, thereby failing to generate assistance. According to the fault handling mechanism, the main control circuit is turned off, and the backup control circuit starts to work, and the EPS can provide 100% of the maximum assistance demand.

[0070] QF 11 , QF 21 , QF 31 does not turn on, preventing the backup control circuit from working when U d2 through L a1 , L b1 and L c1 and the ground in the main control circuit form a short circuit, thereby ensuring that the backup control circuit works normally.

[0071] Example 8: The main drive bridge fails, which is manifested as a short circuit, an open circuit, and being unable to be controlled by the first main pre-drive chip, and being unable to generate a current to provide assistance in the motor winding. According to the fault handling mechanism, the main control circuit is turned off, and the backup control circuit is enabled, and the EPS can provide 100% of the maximum assistance demand.

[0072] When the main control circuit is turned off, QF 11 , QF 21 , QF 31 and the main drive bridge cannot be turned on, preventing the backup control circuit from working when U d2 through L a1 , L b1 and L c1 and the ground in the main control circuit form a short circuit, thereby ensuring that the backup control circuit works normally.

[0073] Example 9: The main phase breaker is open or cannot be driven by the second main pre-drive chip, causing it to not turn on. The current cannot pass through it to reach the motor winding, and assistance cannot be provided. According to the fault handling mechanism, the main control circuit is turned off, and the backup control circuit is enabled, and the EPS can provide 100% of the maximum assistance demand.

[0074] QF 11 , QF 21 , QF 31 is open or cannot turn on, U d2 cannot pass through La1 L b1 and L c1 A short circuit is formed with the ground in the main control circuit, thereby ensuring the normal operation of the backup control circuit. EPS can provide 100% of the maximum assist demand.

[0075] When the main phase circuit breaker fails due to a short circuit, no fault is reported in the current ignition cycle. However, if other components fail at this time, as described in Examples 1 to 8 above, corresponding handling measures can be taken.

[0076] Example 10: When the motor position sensor in the main control circuit fails, the main chip cannot receive angle signals A1 and A2 to calculate steering assist. According to the fault handling mechanism, the backup control circuit starts to work, and the backup chip transmits angle signals A3 and A4 to the main chip, thereby ensuring the normal reception of the motor angle signal and realizing the full provision of steering assist.

[0077] Example 11: When the torque sensor in the main control circuit fails, the main chip cannot receive torque signals T1 and T2 to calculate steering assist. According to the fault handling mechanism, the backup control circuit starts to work, and the backup chip transmits torque signals T3 and T4 to the main chip to ensure that the torque signal is received normally and to achieve full provision of steering assist.

[0078] Based on the above description, the electric power steering system provided in this application embodiment effectively and reliably achieves 100% provision of EPS steering assistance when multiple controller hardware of redundant EPS fails at a single point. This solves the problem of insufficient assistance capability of current redundant EPS after a single point failure, improves the safety and reliability of the EPS system, and meets the EPS motor design requirements in L3 safety level autonomous driving.

[0079] Table 1 below shows the application and Figure 1 The following comparison of existing technologies is shown:

[0080]

[0081]

[0082] As shown in Table 1, compared with the prior art, the electric power steering system provided in this application embodiment can still provide 100% steering assistance when a single point of failure occurs in the main control circuit. This solves the problem of insufficient power assistance capability in current redundant EPS systems after a single point of failure, ensuring the safety of drivers and passengers and improving the driving experience.

[0083] like Figure 4 As shown, this figure is a schematic diagram of another driving circuit provided in an embodiment of this application, and... Figure 3The difference between the shown drive circuit and the drive circuit shown in Fig. 2 is that the three-phase motor has 6 windings per phase, and the first part of the windings has an access ratio of 1, and the second part of the windings has an access ratio of 5 / 6. In this case, the maximum current of the motor does not exceed 5 / 6 times the rated current. When a single point fault occurs in the main control loop, 15 windings can provide a maximum of 5 / 6 times the design power (6 / 5 times the system demand power), and still provide 100% steering assist.

[0084] As shown in Fig. 3, the figure is another drive circuit provided by the embodiment of the present application, which is different from the drive circuit shown in Fig. 2 in that the three-phase motor has 6 windings per phase, and the first part of the windings has an access ratio of 1, and the second part of the windings has an access ratio of 5 / 6. In this case, the maximum current of the motor does not exceed 5 / 6 times the rated current. When a single point fault occurs in the main control loop, 15 windings can provide a maximum of 5 / 6 times the design power (6 / 5 times the system demand power), and still provide 100% steering assist. Figure 5 Figure 3 As shown in Fig. 3, the figure is another drive circuit provided by the embodiment of the present application, which is different from the drive circuit shown in Fig. 2 in that the three-phase motor has 6 windings per phase, and the first part of the windings has an access ratio of 1, and the second part of the windings has an access ratio of 5 / 6. In this case, the maximum current of the motor does not exceed 5 / 6 times the rated current. When a single point fault occurs in the main control loop, 15 windings can provide a maximum of 5 / 6 times the design power (6 / 5 times the system demand power), and still provide 100% steering assist.

[0085] The embodiment of the present application also provides a vehicle, which comprises the electric power assisted steering system as described in the above embodiment.

[0086] It should be understood that in the present application, "at least one" means one or more, and "multiple" means two or more. "And / or" is used to describe the relationship between the associated objects, which means that there can be three kinds of relationships, for example, "A and / or B" can mean: only A, only B, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects. "At least one of the following" or similar expressions means any combination of these items, including any combination of single or multiple items. For example, at least one of a, b or c, can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0087] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with a preferred embodiment, it is not intended to limit the present application. Any person skilled in the art can make many possible changes and modifications to the technical solution of the present application, or modify it into equivalent embodiments with equivalent changes, without departing from the scope of the technical solution of the present application, by using the disclosed methods and technical contents. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, without departing from the technical solution of the present application, still falls within the scope of protection of the technical solution of the present application.​

Claims

1. An electric power steering system, characterized in that, Comprising: A controller, a three-phase motor, a main phase line circuit breaker, a main drive axle, a standby phase line circuit breaker, and a standby drive axle; The input end of the main drive axle is used to connect to the main power supply; The input end of the main phase line circuit breaker is used to connect to the output end of the main drive axle, and the output end of the main phase line circuit breaker is used to connect to the first partial winding of each phase of the three-phase motor; The input end of the standby drive axle is used to connect to the standby power supply; The input end of the standby phase line circuit breaker is used to connect to the output end of the standby drive axle, and the output end of the standby phase line circuit breaker is used to connect to the second partial winding of each phase of the three-phase motor; Each phase of the three-phase motor includes n windings, the access ratio of the first partial winding is 1, and the access ratio of the second partial winding is (n - m) / n, where n and m are positive integers and m < n; the access ratio of the first partial winding is greater than the access ratio of the second partial winding; The designed power of the standby control circuit of the standby phase line circuit breaker and the standby drive axle is n / (n - m) times the system required power; The controller is used to control the main phase line circuit breaker to open and the standby phase line circuit breaker to close when the main control circuit fails.

2. The system according to claim 1, characterized in that, The controller is used to control the main phase line circuit breaker to close and the standby phase line circuit breaker to open when the main control circuit is not faulty.

3. The system according to claim 1 or 2, characterized in that, The main phase line circuit breaker includes a first switching tube, a second switching tube, and a third switching tube; the standby phase line circuit breaker includes a fourth switching tube, a fifth switching tube, and a sixth switching tube; The first switching tube is connected to the first partial winding of the first phase of the three-phase motor, the second switching tube is connected to the first partial winding of the second phase of the three-phase motor, and the third switching tube is connected to the first partial winding of the third phase of the three-phase motor; The fourth switching tube is connected to the second partial winding of the first phase of the three-phase motor, the fifth switching tube is connected to the second partial winding of the second phase of the three-phase motor, and the sixth switching tube is connected to the second partial winding of the third phase of the three-phase motor; The controller is specifically used to control the first switching tube, the second switching tube, and the third switching tube to open and the fourth switching tube, the fifth switching tube, and the sixth switching tube to close when the main control circuit fails.

4. The system according to claim 1, characterized in that, (n - m) / n is greater than or equal to 0.

6.

5. The system according to claim 1, characterized in that, n is any value in the range of 4 - 6.

6. The system according to claim 5, characterized in that, When n = 4, m = 1; when n = 5 or 6, m = 1 or 2.

7. The system according to claim 1, characterized in that, The failure of the main control circuit includes at least one of the following failures: Main power supply, main power supply chip, filter circuit, main chip, main transceiver circuit, first main pre-driver chip, second main pre-driver chip, main drive axle, main phase line circuit breaker, main motor position sensor, main torque sensor.

8. A vehicle, characterized in that, An electric power steering system according to any one of claims 1 - 7 is included.

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