Motor protection circuit, motor power supply system and electronic equipment

Abstract

The application provides a motor protection circuit, a motor power supply system and an electronic device, and belongs to the technical field of electronics. The motor protection circuit comprises: an on-off control circuit; the on-off control circuit is connected with a three-phase inverter and a motor, and is used for disconnecting at least two phase current output ends of the three-phase inverter and the motor in the case that the three-phase inverter has a control fault, so that there is no electrical connection loop between the three-phase inverter and the motor, and the backflow of back electromotive force current generated due to the back electromotive force of the motor through the three-phase inverter is effectively prevented, and the device damage problem of the three-phase inverter, a battery pack and other devices connected with the motor due to the back electromotive force current is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronics, and in particular to a motor protection circuit, a motor power supply system and an electronic device. BACKGROUND

[0002] The motor control circuit is a core component of the power system of a new energy electric vehicle, which is used to control the vehicle power battery to output a power supply signal with high voltage, large current and large power characteristics through a three-phase inverter to drive the motor to run for the new energy electric vehicle to travel.

[0003] However, the motor generates a high back electromotive force when rotating at a high speed, generating a back electromotive force current. The excessively high back electromotive force current is easy to flow through the freewheeling diode in the power switch tube in the three-phase inverter and backflow to the vehicle power battery, causing damage and even explosion of the vehicle power battery. In this case, an active short circuit (ASC) scheme is usually used to form a short circuit loop connected to the motor by simultaneously turning on the upper bridge arm or the lower bridge arm in the three-phase inverter. At this time, the back electromotive force energy of the motor can be released through the short circuit loop to ensure the safety of the motor.

[0004] However, the ASC scheme is based on the controllability of the three-phase inverter. However, in actual applications, there may be a situation where the three-phase inverter is out of control, making it impossible to effectively implement the motor protection under the ASC scheme, and causing damage to the vehicle battery pack, three-phase inverter and other devices. SUMMARY

[0005] The motor protection circuit, the motor power supply system and the electronic device provided by the embodiments of the present application can effectively prevent the back electromotive force current generated by the motor due to the generation of the back electromotive force from backflowing through the three-phase inverter, and solve the problem of damage to the devices such as the three-phase inverter and the battery pack connected to the motor due to the back electromotive force current.

[0006] In a first aspect, the embodiments of the present application provide a motor protection circuit, which comprises: a on-off control circuit;

[0007] The on-off control circuit is connected with the three-phase inverter and the motor, and is used to disconnect at least two phase current output ends of the three-phase inverter and the motor in the case that the three-phase inverter has a control fault.

[0008] Optionally, the three-phase inverter has a control fault in the case that the three-phase inverter has a fault, or a motor control circuit for controlling the three-phase inverter has a fault.

[0009] Optionally, the three-phase inverter comprises power switch tubes, and the motor is powered by a battery pack through the power switch tubes; and the three-phase inverter is faulty in a case that at least one of the power switch tubes is short-circuited.

[0010] Optionally, the motor control circuit is faulty in a case that the motor control circuit is under voltage.

[0011] Optionally, the three-phase inverter is under control fault in a case that the motor control circuit outputs the target fault signal.

[0012] Optionally, the motor protection circuit further comprises a current detection circuit.

[0013] The current detection circuit is connected with the motor and the three-phase inverter, and is configured to detect a current value of a three-phase current between the motor and the three-phase inverter.

[0014] The on-off control circuit is further configured to disconnect at least two phase current output terminals of the three-phase inverter and the motor in a case that the three-phase inverter is under control fault and the current value of any phase current detected by the current detection circuit exceeds a current threshold.

[0015] Optionally, the current detection circuit comprises three current detection modules.

[0016] Each of the current detection modules is connected with the three-phase inverter and a different phase current output terminal of the motor, and is configured to detect a current value of a phase current output by the connected phase current output terminal.

[0017] Optionally, the current detection module comprises a current sensor.

[0018] The current sensor is connected with the three-phase inverter and the phase current output terminal, and is configured to detect a current value of a phase current output by the connected phase current output terminal.

[0019] Optionally, the on-off control circuit comprises three on-off control modules.

[0020] Each of the on-off control modules is connected with the three-phase inverter and a different phase current output terminal of the motor, and is configured to disconnect the phase current output terminal and the three-phase inverter in a case that the three-phase inverter is under control fault.

[0021] Optionally, the on-off control module comprises a switching device.

[0022] The switching device is connected with the three-phase inverter and the phase current output terminal, and is configured to disconnect the phase current output terminal and the three-phase inverter in a case that the three-phase inverter is under control fault.

[0023] Optionally, the switching device comprises a relay.

[0024] The relay is connected with the three-phase inverter and the phase current output end, and is configured to disconnect the phase current output end and the three-phase inverter in the case that the three-phase inverter has a control fault.

[0025] Optionally, the motor protection circuit further comprises a protection control circuit.

[0026] The protection control circuit is connected with the three-phase inverter and the on-off control circuit, and is configured to control the on-off control circuit to disconnect the three-phase inverter and at least two phase current output ends of the motor in the case that it is determined that the three-phase inverter has a control fault.

[0027] Optionally, the motor protection circuit further comprises a protection control circuit.

[0028] The current detection circuit is connected with the protection control circuit, and is configured to output the current value of the three-phase current to the protection control circuit.

[0029] The protection control circuit is connected with the three-phase inverter and the on-off control circuit, and is configured to control the on-off control circuit to disconnect the three-phase inverter and at least two phase current output ends of the motor in the case that it is determined that the three-phase inverter has a control fault and the current value of any phase current exceeds a current threshold.

[0030] In a second aspect, a motor power supply system is provided, which comprises a motor, a three-phase inverter, and the motor protection circuit of any one of the first aspect.

[0031] In a third aspect, an electronic device is provided, which comprises the motor power supply system of the second aspect.

[0032] The present application has the following advantages:

[0033] In the motor protection circuit of the present application, the on-off control circuit is used to disconnect the three-phase inverter and the motor in the case that it is determined that the three-phase inverter has a control fault, which indicates that the working state of the three-phase inverter is not controlled and the motor protection cannot be implemented by controlling the three-phase inverter. In this way, there is no electrical connection loop between the three-phase inverter and the motor, and the backflow of the counter electromotive force current generated by the counter electromotive force of the motor through the three-phase inverter is effectively prevented, and the damage of the three-phase inverter, the battery pack and other devices connected to the motor due to the counter electromotive force current is solved. BRIEF DESCRIPTION OF DRAWINGS

[0034] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0035] Figure 1 This is a schematic diagram of the working circuit of a motor provided in an embodiment of this application;

[0036] Figure 2 This is one of the structural schematic diagrams of the motor protection circuit provided in the embodiments of this application;

[0037] Figure 3 This is a second schematic diagram of the structure of the motor protection circuit provided in the embodiments of this application;

[0038] Figure 4 This is the third schematic diagram of the motor protection circuit provided in the embodiments of this application;

[0039] Figure 5 This is one of the schematic diagrams of the current path of the back electromotive force current provided in the embodiments of this application;

[0040] Figure 6 This is a second schematic diagram of the current path of the back electromotive force current provided in the embodiments of this application;

[0041] Figure 7 Fourth schematic diagram of the motor protection circuit provided in the embodiments of this application;

[0042] Figure 8 Fifth schematic diagram of the motor protection circuit provided in the embodiments of this application;

[0043] Figure 9 This is the sixth schematic diagram of the structure of the motor protection circuit provided in the embodiments of this application;

[0044] Figure 10 This is a flowchart of a motor protection method provided in an embodiment of this application. Detailed Implementation

[0045] Exemplary embodiments of the present application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the scope of the present application to those skilled in the art.

[0046] To facilitate a better understanding of the technical solution of this application, the working circuit of the motor will be described first below. For example... Figure 1 As shown, the working circuit of motor 1 includes: a three-phase inverter 2, and a motor control circuit ( Figure 1The motor 1, the bus capacitor 3 and the battery pack 4 are not shown in the figure. The three-phase inverter 2 is connected with the motor 1 and the motor control circuit respectively. Moreover, the three-phase inverter 2 is also connected with the battery pack 4 through the bus capacitor 3.

[0047] The motor 1 has three phase current output terminals, including a first phase current output terminal, a second phase current output terminal and a third phase current output terminal. The three phase current output terminals are used to output three-phase current generated by the motor 1. The three-phase inverter 2 generally includes three bridge arm circuits, including a first bridge arm circuit 21, a second bridge arm circuit 22 and a third bridge arm circuit 23. The first bridge arm circuit 21 is connected with the motor control circuit, the bus capacitor 3, the battery pack 4 and the first phase current output terminal of the motor 1. The second bridge arm circuit 22 is connected with the motor control circuit, the bus capacitor 3, the battery pack 4 and the second phase current output terminal of the motor 1. The third bridge arm circuit 23 is connected with the motor control circuit, the bus capacitor 3, the battery pack 4 and the third phase current output terminal of the motor 1. The motor control circuit is used to control the operation of the three-phase inverter 2.

[0048] Specifically, in the three-phase inverter 2, each bridge arm circuit includes a power switch tube of an upper bridge arm and a power switch tube of a lower bridge arm. In some embodiments, each bridge arm circuit includes one power switch tube of an upper bridge arm and one power switch tube of a lower bridge arm. It is not difficult to understand that the three-phase inverter 2 includes three power switch tubes of upper bridge arms and three power switch tubes of lower bridge arms.

[0049] For example, in the three-phase inverter 2, the power switch tube is an Insulate-Gate Bipolar Transistor (IGBT). The first bridge arm circuit 21 includes a first IGBT Q1 of an upper bridge arm and a second IGBT Q2 of a lower bridge arm. The first end (i.e. the control end) of the first IGBT Q1 is connected with the motor control circuit, the second end of the first IGBT Q1 is connected with the battery pack 4 and the bus capacitor 3, and the third end of the first IGBT Q1 is connected with the first phase current output terminal of the motor 1 and the second end of the second IGBT Q2. The first end (i.e. the control end) of the second IGBT Q2 is connected with the motor control circuit, and the third end of the second IGBT Q2 is connected with the battery pack 4 and the bus capacitor 3.

[0050] The second bridge arm circuit 22 includes a third IGBT Q3 of the upper bridge arm and a fourth IGBT Q4 of the lower bridge arm. The first end (i.e., the control end) of the third IGBT Q3 is connected with the motor control circuit, the second end of the third IGBT Q3 is connected with the battery pack 4 and the bus capacitor 3, and the third end of the third IGBT Q3 is connected with the second-phase current output end of the motor 1 and the second end of the fourth IGBT Q4. The first end (i.e., the control end) of the fourth IGBT Q4 is connected with the motor control circuit, and the third end of the fourth IGBT Q4 is connected with the battery pack 4 and the bus capacitor 3.

[0051] The third bridge arm circuit 23 includes a fifth IGBT Q5 of the upper bridge arm and a sixth IGBT Q6 of the lower bridge arm. The first end (i.e., the control end) of the fifth IGBT Q5 is connected with the motor control circuit, the second end of the fifth IGBT Q5 is connected with the battery pack 4 and the bus capacitor 3, and the third end of the fifth IGBT Q5 is connected with the third-phase current output end of the motor 1 and the second end of the sixth IGBT Q6. The first end (i.e., the control end) of the sixth IGBT Q6 is connected with the motor control circuit, and the third end of the sixth IGBT Q6 is connected with the battery pack 4 and the bus capacitor 3.

[0052] The motor control circuit is configured to control the conduction or turn-off of the first IGBT Q1, the second IGBT Q2, the third IGBT Q3, the fourth IGBT Q4, the fifth IGBT Q5, and the sixth IGBT Q6, so as to control the communication or disconnection between the battery pack 4 and the first-phase current output end, the second-phase current output end, and the third-phase current output end of the motor 1, thereby controlling the working state of the motor 1. In some embodiments, the power switch tube in the three-phase inverter 2 can also be a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET).

[0053] When the motor 1 rotates at a high speed, a high back electromotive force is generated, and a back electromotive force current is generated. The over-high back electromotive force current is likely to flow through the freewheeling diode in the power switch tube in the three-phase inverter 2, and back-irrigate to the battery pack 4 and the bus capacitor 3, thereby causing damage or even explosion of the battery pack 4. The bus capacitor 3 may be over-voltage under the back-irrigation of the over-high back electromotive force current, and the over-voltage bus capacitor 3 may damage the power switch tube in the three-phase inverter 2, thereby causing short circuit or open circuit of the power switch tube.

[0054] Currently, an active short circuit (ASC) scheme is usually adopted to avoid the high back-EMF (electromotive force) backflow of the motor 1. Under the ASC scheme, the power switch tubes in the upper bridge arm or the lower bridge arm of the three-phase inverter 2 are controlled to be simultaneously turned on to form a short circuit loop connected with the motor 1, so that the back-EMF energy of the motor 1 can be released through the short circuit loop, the back-EMF current generated by the back-EMF is avoided to backflow, and the use safety of the motor 1 is ensured.

[0055] However, the ASC scheme is based on the controllability of the three-phase inverter 2. In actual applications, there may be a situation that the three-phase inverter 2 is out of control, so that the motor 1 protection under the ASC scheme cannot be effectively performed, and the problems of damage of the battery pack 4, the three-phase inverter 2 and the like occur.

[0056] For example, if the motor control circuit fails, the motor control circuit cannot directly drive the power switch tubes in the three-phase inverter 2 to be turned on or turned off. Therefore, the ASC scheme cannot be effectively performed.

[0057] If the power switch tubes in the three-phase inverter 2 fail, at least one power switch tube may be short-circuited. At this time, if the ASC scheme is triggered to be performed, in the case that the short-circuited power switch tube does not belong to the power switch tubes that need to be turned on under the ASC scheme, the short-circuited power switch tube will cause the bridge arm circuit in which the power switch tube is located to be short-circuited. The upper bridge arm and the lower bridge arm in the short-circuited bridge arm circuit are directly connected, so that the battery pack 4 is short-circuited, and there is a risk of damage of the battery pack 4, fire and explosion of the three-phase inverter 2. For example, in the case that the power switch tubes in the lower bridge arm need to be turned on under the ASC scheme, if there is a short-circuited power switch tube in the upper bridge arm, the short-circuited power switch tube and the power switch tube turned on under the ASC control will cause the bridge arm circuit in which the short-circuited power switch tube is located to be short-circuited, and the upper bridge arm and the lower bridge arm in the short-circuited bridge arm circuit are directly connected.

[0058] It should be noted that the introduction of the present application (for example Figure 1 , Figure 3 , etc.) takes the first-phase current output end as the output end of the U-phase current of the motor 1, the second-phase current output end as the output end of the V-phase current of the motor 1, and the third-phase current output end as the output end of the W-phase current of the motor 1 as an example.

[0059] Please refer to Figure 2 , which shows a structure schematic diagram of a motor protection circuit provided by an embodiment of the present application, which can solve the foregoing problems to a certain extent. As shown in Figure 2 , the motor protection circuit 5 comprises: a on-off control circuit 51.

[0060] The on-off control circuit 51 is connected with the three-phase inverter 2 and the motor 1. The on-off control circuit 51 is configured to disconnect at least two phase current output terminals of the three-phase inverter 2 and the motor 1 in the case that the three-phase inverter 2 has a control fault.

[0061] Optionally, the on-off control circuit 51 is configured to disconnect any two phase current output terminals of the three-phase inverter 2 and the motor 1, or disconnect all three phase current output terminals of the three-phase inverter 2 and the motor 1 in the case that the three-phase inverter 2 has a control fault. Correspondingly, the on-off control circuit 51 is configured to connect the three-phase inverter 2 and the motor 1 in the case that the three-phase inverter 2 does not have a control fault.

[0062] In some embodiments of the present application, the control fault of the three-phase inverter 2 can be caused by a fault of the three-phase inverter 2 itself, which leads to the uncontrolled control fault of the three-phase inverter 2. Alternatively, the control fault of the three-phase inverter 2 can be caused by a fault of the motor control circuit that controls the operation of the three-phase inverter 2, which leads to the uncontrolled control fault of the three-phase inverter 2. That is, the three-phase inverter 2 has a control fault in the case that the three-phase inverter 2 has a fault, or the motor control circuit that controls the operation of the three-phase inverter 2 has a fault.

[0063] Based on this, the on-off control circuit 51 can also be configured to disconnect at least two phase current output terminals of the three-phase inverter 2 and the motor 1 in the case that the three-phase inverter 2 has a fault, or the motor control circuit has a fault.

[0064] In an alternative case, the on-off control circuit 51 can be configured to actively monitor the working state of the three-phase inverter 2 and the motor control circuit to determine whether the three-phase inverter 2 or the motor control circuit has a fault. Then, the on-off control circuit 51 is configured to disconnect at least two phase current output terminals of the three-phase inverter 2 and the motor 1 in the case that the three-phase inverter 2 or the motor control circuit has a fault.

[0065] In some embodiments, the three-phase inverter 2 includes power switch tubes. The motor 1 receives power supply from the battery pack 4 through the power switch tubes. Optionally, the three-phase inverter 2 includes power switch tubes of upper bridge arms and power switch tubes of lower bridge arms.

[0066] In this case, the fault of the three-phase inverter 2 is usually caused by a short circuit fault of the power switch tubes in the three-phase inverter 2. Thus, the three-phase inverter 2 has a fault in the case that at least one power switch tube is short-circuited. Moreover, as mentioned above, the short circuit of one power switch tube in the three-phase inverter 2 can cause damage to the battery pack 4 and the three-phase inverter 2.

[0067] The on-off control circuit 51 can also be configured to disconnect at least two phase current outputs of the three-phase inverter 2 and the motor 1 in the event of a short circuit of at least one power switch tube in the three-phase inverter 2. Optionally, the on-off control circuit 51 can be connected to each power switch tube in the three-phase inverter 2 to monitor whether a short circuit occurs in each power switch tube.

[0068] In an alternative implementation, the on-off control circuit 51 comprises a desaturation circuit corresponding to each power switch tube. The desaturation circuit is connected to the corresponding power switch tube to collect the drain-source voltage Vce of the power switch tube, and in the event that the drain-source voltage Vce exceeds a voltage threshold, it is determined that the drain-source current Ids of the power switch tube is too large, the power switch tube exits the saturation region, and a short circuit occurs in the power switch tube.

[0069] For example, the three-phase inverter 2 has the structure of the three-phase inverter 2 shown in the foregoing Figure 1 The on-off control circuit 51 can be connected to each power switch tube in the first bridge arm circuit 21, the second bridge arm circuit 22, and the third bridge arm circuit 23. The on-off control circuit 51 is configured to monitor a short circuit of each power switch tube.

[0070] In other embodiments, the three-phase inverter 2 operates under the control of a motor control circuit. The motor control circuit has a fault in the event of an under-voltage of the motor control circuit. Accordingly, the on-off control circuit 51 is also configured to disconnect at least two phase current outputs of the three-phase inverter 2 and the motor 1 in the event of an under-voltage of the motor control circuit. Optionally, the motor control circuit comprises a power supply terminal and a control output terminal corresponding to each power switch tube. The motor control circuit is configured to receive a circuit operating voltage provided by an external power supply through the power supply terminal, and the circuit operating voltage is used to maintain the operation of the motor control circuit. The motor control circuit is configured to output a conduction control voltage to the power switch tube through the control output terminal, and the conduction control voltage is used to drive the power switch tube to conduct.

[0071] Obviously, if the circuit working voltage inputted by the power supply end of the motor control circuit is insufficient, the motor control circuit cannot maintain normal operation, and thus cannot control the three-phase inverter 2 to operate normally. If the on control voltage outputted by the control output end of the motor control circuit is insufficient, the motor control circuit cannot drive the power switch tube in the three-phase inverter 2 to normally turn on, so that the power switch tube is not controlled. Therefore, in some embodiments, the on-off control circuit 51 can be connected with the motor control circuit, for collecting the circuit working voltage inputted by the power supply end of the motor control circuit and the on control voltage outputted by the control output end of the motor control circuit, and in the case that the circuit working voltage is less than a first voltage threshold or the on control voltage is less than a second voltage threshold, determining that the motor control circuit is under voltage and disconnecting at least two phase current output ends of the three-phase inverter 2 and the motor 1.

[0072] The first voltage threshold can be at least the minimum circuit working voltage at which the motor control circuit can operate normally. The second voltage threshold can be at least the minimum on control voltage at which the power switch tube can turn on. For example, in the case that the power switch tube is an IGBT, the second voltage threshold can be 15V; in the case that the power switch tube is a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), the second voltage threshold can be 18V.

[0073] In some embodiments, the on-off control circuit 51 can actively monitor the fault conditions of the three-phase inverter 2 and the motor control circuit, thereby effectively ensuring the accuracy of the fault judgment of the three-phase inverter 2 and the motor control circuit, and thus facilitating the disconnection of the three-phase inverter 2 and the motor 1 in a timely manner when the three-phase inverter 2 or the motor control circuit fails, so that there is no electrical connection loop between the three-phase inverter 2 and the motor 1, effectively preventing the back-feeding of the counter electromotive force current of the motor 1 through the three-phase inverter 2, and solving the device damage problem caused by the counter electromotive force current of the motor connected three-phase inverter, battery pack and other devices.

[0074] In another alternative case, the on-off control circuit 51 can also passively monitor whether the three-phase inverter 2 or the motor control circuit fails, to determine the fault conditions of the three-phase inverter 2 and the motor control circuit. Then, in the case that the three-phase inverter 2 or the motor control circuit is determined to fail, at least two phase current output ends of the three-phase inverter 2 and the motor 1 are disconnected.

[0075] In some embodiments, the motor control circuit is further configured to output a target fault signal in case that the three-phase inverter 2 is detected to be faulty, or the motor control circuit is detected to be faulty. Accordingly, the on-off control circuit 51 can be configured to disconnect the at least two phase current outputs of the three-phase inverter 2 and the motor 1 in case that the target fault signal is outputted by the motor control circuit. For example, the motor control circuit can be connected with the on-off control circuit 51, and configured to output the target fault signal to the on-off control circuit 51 in case that the three-phase inverter 2 is detected to be faulty, or the motor control circuit is detected to be faulty. Thus, the on-off control circuit 51 is enabled to determine that the target fault signal is outputted by the motor control circuit, and disconnect the at least two phase current outputs of the three-phase inverter 2 and the motor 1.

[0076] Optionally, the motor control circuit can be configured to detect short circuit of each power switch in the three-phase inverter 2, and output the target fault signal in case that at least one power switch in the three-phase inverter 2 is detected to be short-circuited. Further optionally, the motor control circuit can be connected with each power switch in the three-phase inverter 2, and configured to monitor whether each power switch is short-circuited. In an optional implementation, the motor control circuit comprises a desaturation circuit corresponding to each power switch. The desaturation circuit is connected with the corresponding power switch, and configured to collect a drain-source voltage Vce of the power switch, and determine that the power switch is out of saturation region and short-circuited in case that the drain-source voltage Vce exceeds a voltage threshold, which indicates that a drain-source current Ids of the power switch is too large.

[0077] Further optionally, the motor control circuit can be configured to output the target fault signal in case that the motor control circuit is detected to be under-voltage. Specifically, the motor control circuit can be configured to monitor a circuit working voltage inputted at a power supply terminal of the motor control circuit, and a turn-on control voltage to be outputted at a control output terminal of the motor control circuit. Thus, the motor control circuit is determined to be under-voltage in case that the circuit working voltage is less than a first voltage threshold, or the turn-on control voltage is less than a second voltage threshold, and the motor control circuit is determined to be faulty and output the target fault signal.

[0078] For example, the motor control circuit includes a motor drive chip. The motor drive chip includes a desaturation pin, a power supply pin (i.e., a power supply end), and a control output pin (i.e., a control output end). The motor drive chip is integrated with a desaturation circuit corresponding to each power switch tube. In the motor drive chip, the desaturation circuit is connected to the source and drain of the power switch tube through the desaturation pin, used to collect the drain-source voltage Vce of the power switch tube, and generate an intelligent power module (IPM) fault signal (i.e., a target fault signal) and report the IPM fault signal when the drain-source voltage Vce exceeds a voltage threshold.

[0079] The motor drive chip is also used to monitor the circuit operating voltage input by the power supply pin and the conduction control voltage to be output from the control output pin, so as to generate an IPM fault signal and output a target fault signal when the circuit operating voltage is less than a first voltage threshold, or the conduction control voltage is less than a second voltage threshold. Thus, the on-off control circuit 51 can be used to disconnect at least two phase current output ends of the three-phase inverter 2 and the motor 1 when the motor control circuit outputs the target fault signal. Correspondingly, the on-off control circuit 51 can be used to connect the three phase current output ends of the three-phase inverter 2 and the motor 1 when the motor control circuit does not output the target fault signal.

[0080] In some embodiments, the on-off control circuit 51 can reuse the fault detection results of the motor control circuit on the three-phase inverter 2 and the fault detection results of itself, so as to directly disconnect at least two phase current output ends of the three-phase inverter 2 and the motor 1 when the motor control circuit outputs a target fault signal indicating that the three-phase inverter 2 or the motor control circuit has a fault. Compared with the scheme in which the on-off control circuit 51 actively monitors whether the three-phase inverter 2 and the motor control circuit have faults, the on-off control circuit 51 does not need to have a part of circuit for monitoring faults of the three-phase inverter 2 and the motor control circuit, thereby reducing the circuit area of the on-off control circuit 51 and reducing the cost of the on-off control circuit 51.

[0081] In the embodiments of the present application, the motor protection circuit includes an on-off control circuit. The motor is connected to the three-phase inverter through the on-off control circuit. The on-off control circuit is used to disconnect the three-phase inverter and the motor when the three-phase inverter has a control fault, indicating that the working state of the three-phase inverter is not controlled and the motor protection cannot be implemented by controlling the three-phase inverter, so that there is no electrical connection loop between the three-phase inverter and the motor, effectively preventing the back-feeding of the back electromotive force current generated by the motor due to the back electromotive force through the three-phase inverter, and solving the problem of device damage of the three-phase inverter, the battery pack, and other devices connected to the motor due to the back electromotive force current.

[0082] In the case of back electromotive force generated by the motor 1, even if the power switch tube of the three-phase inverter 2 is in an off state. The back electromotive force current generated by the back electromotive force can also flow to the battery pack 4 and the bus capacitor 3 through the freewheeling diode in the power switch tube of the three-phase inverter 2. Then, it is backfilled to the motor 1 through the freewheeling diode in the power switch tube of the three-phase inverter 2. At this time, the three-phase current between the motor 1 and the three-phase inverter 2 exists forward current and reverse current. The current direction of the forward current is the same as the current direction of the phase current output by the motor 1 when it is working normally. The current direction of the reverse current is opposite to the current direction of the phase current output by the motor 1 when it is working normally.

[0083] In some embodiments of the present application, there is a case that the motor generates a small back electromotive force to generate a small back electromotive force current, so that the current of each phase of the motor 1 is small, including the reverse current backfilled to the motor 1. A certain degree of small reverse current will not cause damage to the battery pack, three-phase inverter and other devices connected to the motor. In this way, the motor protection circuit 5 can further obtain the size of the three-phase current between the motor 1 and the three-phase inverter 2 on the basis of the control failure of the three-phase inverter 2, so as to more accurately judge whether the three-phase inverter 2 and the motor 1 need to be disconnected according to the size of the three-phase current, and realize more accurate motor protection. Based on this, as shown in the figure, the motor protection circuit 5 further includes a current detection circuit 53. Figure 3

[0084] The current detection circuit 53 is connected with the motor 1 and the three-phase inverter 2. The current detection circuit 53 is used to detect the current value of the three-phase current between the motor 1 and the three-phase inverter 2.

[0085] The on-off control circuit 51 is used to disconnect at least two phase current output ends of the three-phase inverter 2 and the motor 1 in the case that the three-phase inverter 2 has a control failure and the current value of any phase current detected by the current detection circuit 53 exceeds the current threshold.

[0086] In some embodiments, the current detection circuit 53 is connected with the on-off control circuit 51, and is used to output the current value of the three-phase current between the motor 1 and the three-phase inverter 2 to the on-off control circuit 51. Correspondingly, the on-off control circuit 51 is used to disconnect at least two phase current output ends of the three-phase inverter 2 and the motor 1 in the case that the three-phase inverter 2 has a control failure and the current value of any phase current exceeds the current threshold.

[0087] ​Optionally, the on-off control circuit 51 can be configured to determine, for each of the received phase currents, whether the current value of the phase current exceeds the current threshold, and to disconnect at least two phase current output terminals of the three-phase inverter 2 and the motor 1 in the case where the current value of one of the phase currents exceeds the current threshold; and to connect all three phase current output terminals of the three-phase inverter 2 and the motor 1 in the case where the current values of all three phase currents do not exceed the current threshold.

[0088] In an optional implementation, as shown in Figure 4 The current detection circuit 53 includes three current detection modules 531.

[0089] Each current detection module 531 is connected to a different phase current output terminal of the three-phase inverter 2 and the motor 1. Each current detection module 531 is configured to detect the current value of the phase current output by the connected phase current output terminal. Optionally, a single current detection module 531 can include a current sensor. The current sensor is connected to the three-phase inverter 2 and the phase current output terminal, and is configured to detect the current value of the phase current output by the connected phase current output terminal.

[0090] Specifically, the three current detection modules 531 include a first current detection module, a second current detection module, and a third current detection module. The first current detection module is connected to the first phase current output terminal of the three-phase inverter 2 and the motor 1, and is configured to detect the current value of the U-phase current output by the motor 1. The second current detection module is connected to the second phase current output terminal of the three-phase inverter 2 and the motor 1, and is configured to detect the current value of the V-phase current output by the motor 1. The third current detection module is connected to the third phase current output terminal of the three-phase inverter 2 and the motor 1, and is configured to detect the current value of the W-phase current output by the motor 1. The on-off control circuit 51 is configured to disconnect at least two phase current output terminals of the three-phase inverter 2 and the motor 1 in the case where the three-phase inverter 2 has a control fault and the current value of any of the U-phase current, the V-phase current, and the W-phase current exceeds the current threshold.

[0091] It should be noted that there can be at least two reasons why at least one phase current exceeds the current threshold in the embodiments of the present application.

[0092] The first reason is that the back electromotive force generated by the motor 1 is too large. Even if the power switch tube of the three-phase inverter 2 is in an off state. But the excessive back electromotive force current (that is, the reverse current) generated by the back electromotive force can flow back to the motor 1 through the freewheeling diode in the power switch tube of the three-phase inverter 2 after passing through the battery pack 4 and the bus capacitor 3. At this time, the excessive back electromotive force current will cause the phase current flowing back to the motor 1 to be large, so the three-phase current between the motor 1 and the three-phase inverter 2 is large. Among them, the phase current flowing back to the motor 1 is opposite in direction to the phase current output by the motor 1 when it is working normally.

[0093] Please refer to Figure 5 , which shows a schematic diagram of a current path of a back electromotive force current. Figure 5 Among them, the structure of the three-phase inverter 2 is taken as an example Figure 1 , and the motor 1 is also connected with the bus capacitor 3 and the battery pack 4 in its working circuit through the three-phase inverter 2.

[0094] As shown in Figure 5 , the motor 1 generates a large U-phase current (that is, back electromotive force current) from the first phase current output due to a large back electromotive force. The U-phase current flows to the bus capacitor 3 and the battery pack 4 through the freewheeling diode of the power switch tube Q1 in the upper bridge arm of the first bridge arm circuit 21 in the three-phase inverter 2. Further, after flowing out from the bus capacitor 3 and the battery pack 4, it is divided into two paths, one of which flows to the second phase current output terminal of the motor 1 through the freewheeling diode of the power switch tube Q4 in the lower bridge arm of the second bridge arm circuit 22 in the three-phase inverter 2, and flows back to the motor 1; the other flows to the third phase current output terminal of the motor 1 through the freewheeling diode of the power switch tube Q6 in the lower bridge arm of the third bridge arm circuit 23 in the three-phase inverter 2, and flows back to the motor 1. Obviously, the three-phase current between the three-phase inverter 2 and the motor 1 is large.

[0095] It should be noted that similarly, the back electromotive force current generated by the motor 1 due to the large back electromotive force can also flow out from the second phase current output terminal, and then flow to the first phase current output terminal and the third phase current output terminal through the three-phase inverter 2, the bus capacitor 3, and the battery pack 4, to flow back to the motor 1. Or, the back electromotive force current generated by the motor 1 due to the large back electromotive force can also flow out from the third phase current output terminal, and then flow to the first phase current output terminal and the second phase current output terminal through the three-phase inverter 2, the bus capacitor 3, and the battery pack 4, to flow back to the motor 1. Or, the back electromotive force current generated by the motor 1 due to the large back electromotive force can also flow out from the first phase current output terminal and the second phase current output terminal, and then flow to the third phase current output terminal through the three-phase inverter 2, the bus capacitor 3, and the battery pack 4, to flow back to the motor 1. Of course, there are other paths for the back electromotive force current to flow, which are not enumerated in the embodiments of the present application.

[0096] In the first reason, the excessive back electromotive force current back to the battery pack 4 can cause the risk of damage or even explosion. And, the bus capacitor 3 will be overvoltage under the back of the excessive back electromotive force current, and the overvoltage bus capacitor 3 can cause the power switch tube of the three-phase inverter 2 to be overvoltage breakdown, causing the power switch tube to be short-circuited or open-circuited, causing the damage of the power switch tube in the three-phase inverter 2, and even the risk of fire and explosion.

[0097] The second reason is that even if the back electromotive force generated by the motor 1 is small. But in the case of at least one short-circuit bridge arm circuit, that is, the upper bridge arm and the lower bridge arm are connected, there will be at least one phase of excessive phase current. Please refer to Figure 6 , which shows a current path diagram of back electromotive force current. Figure 6 In the above, the structure of the three-phase inverter 2 is shown in Figure 1 , and the motor 1 is connected with the bus capacitor 3 and the battery pack 4 in its working circuit through the three-phase inverter 2.

[0098] As shown in Figure 6 , in the case of short-circuit of the first bridge arm circuit 21 of the three-phase inverter 2, the power switch tube Q1 of the upper bridge arm and the power switch tube Q2 of the lower bridge arm in the first bridge arm circuit 21 are short-circuited. The motor 1 outputs V-phase current (i.e. back electromotive force current) from the second phase current output end due to the generation of back electromotive force. The V-phase current flows through the freewheeling diode of the power switch tube Q3 of the upper bridge arm in the second bridge arm circuit 22 of the three-phase inverter 2, to the freewheeling diode of the power switch tube Q1 of the upper bridge arm in the first bridge arm circuit 21. And, the motor 1 outputs W-phase current (i.e. back electromotive force current) from the third phase current output end due to the generation of back electromotive force. The W-phase current flows through the freewheeling diode of the power switch tube Q5 of the upper bridge arm in the third bridge arm circuit 23 of the three-phase inverter 2, to the freewheeling diode of the power switch tube Q1 of the upper bridge arm in the first bridge arm circuit 21. The V-phase current and the W-phase current both flow through the freewheeling diode of the power switch tube Q1 of the upper bridge arm in the first bridge arm circuit 21, to the first phase current output end of the motor 1, and back to the motor 1. Obviously, in this case, the U-phase current between the motor 1 and the three-phase inverter 2 will be large.

[0099] It should be noted that, similarly, in the case of short circuit of the second bridge arm circuit 22 of the three-phase inverter 2, the motor 1 outputs a U-phase current (i.e., a back electromotive force current) from the first phase current output terminal due to generation of a back electromotive force. The U-phase current flows to the freewheeling diode of the power switch Q3 of the upper arm of the second bridge arm circuit 22 through the freewheeling diode of the power switch Q1 of the upper arm of the first bridge arm circuit 21 of the three-phase inverter 2. In addition, the motor 1 outputs a W-phase current (i.e., a back electromotive force current) from the third phase current output terminal due to generation of a back electromotive force. The W-phase current flows to the freewheeling diode of the power switch Q3 of the upper arm of the second bridge arm circuit 22 through the freewheeling diode of the power switch Q5 of the upper arm of the third bridge arm circuit 23 of the three-phase inverter 2. Both the U-phase current and the W-phase current flow to the second phase current output terminal of the motor 1 through the freewheeling diode of the power switch Q3 of the upper arm of the second bridge arm circuit 22, and are backfilled to the motor 1. Obviously, in this case, a V-phase current between the motor 1 and the three-phase inverter 2 is large. Of course, there are other paths for the back electromotive force current, which are not enumerated herein.

[0100] In the second case, overcurrent occurs in the power switches of the three-phase inverter 2, and the overcurrent causes the junction temperature of the three-phase inverter 2 to be too high and be damaged, thereby causing a risk of fire or explosion.

[0101] In some embodiments, the motor protection circuit 5, on the basis of determining that the three-phase inverter 2 has a control fault, further collects the sizes of the three-phase currents between the motor 1 and the three-phase inverter 2, so as to more accurately determine whether the three-phase inverter 2 and the motor 1 need to be disconnected, thereby achieving more accurate motor protection.

[0102] In the embodiments of the present application, the on-off control circuit 51 is connected with the three-phase inverter 2 and the motor 1. The on-off control circuit 51 is configured to disconnect at least two phase current output terminals of the three-phase inverter 2 and the motor 1 in the case that the three-phase inverter 2 has a control fault.

[0103] Optionally, as shown in Figure 7 the on-off control circuit 51 can include three on-off control modules 511. Each on-off control module 511 is connected with the three-phase inverter 2 and a different phase current output terminal of the motor 1. Each on-off control module 511 is configured to disconnect the phase current output terminal connected with the on-off control module 511 and the three-phase inverter 2 in the case that the three-phase inverter 2 has a control fault. Correspondingly, each on-off control module 511 is configured to connect the phase current output terminal connected with the on-off control module 511 and the three-phase inverter 2 in the case that the three-phase inverter 2 does not have a control fault.

[0104] Specifically, please continue to refer to Figure 7The three on-off control modules 511 include a first on-off control module, a second on-off control module, and a third on-off control module. The first on-off control module is connected with the first phase current output end of the motor 1. The first on-off control module is configured to disconnect the first phase current output end and the three-phase inverter 2 in the case that the three-phase inverter 2 has a control fault. The second on-off control module is connected with the second phase current output end of the motor 1. The second on-off control module is configured to disconnect the second phase current output end and the three-phase inverter 2 in the case that the three-phase inverter 2 has a control fault. The third on-off control module is connected with the third phase current output end of the motor 1. The third on-off control module is configured to disconnect the third phase current output end and the three-phase inverter 2 in the case that the three-phase inverter 2 has a control fault.

[0105] In some embodiments, as shown in FIG. 5, the on-off control module 511 includes a switching device S. The switching device S is connected with the three-phase inverter 2 and the phase current output end. The switching device S is configured to disconnect the phase current output end and the three-phase inverter 2 connected with the switching device S in the case that the three-phase inverter 2 has a control fault. Correspondingly, the switching device S is also configured to connect the phase current output end and the three-phase inverter 2 connected with the switching device S in the case that the three-phase inverter 2 does not have a control fault. Figure 7

[0106] Optionally, the switching device S can include a relay. The relay is connected with the three-phase inverter 2 and the phase current output end. The relay is configured to disconnect the phase current output end and the three-phase inverter 2 connected with the relay in the case that the three-phase inverter 2 has a control fault. Correspondingly, the relay is configured to connect the phase current output end and the three-phase inverter 2 connected with the relay in the case that the three-phase inverter 2 does not have a control fault.

[0107] It should be noted that the switching device S can also be a device such as an optical coupler that can isolate the connection between the phase current output end and the three-phase inverter 2, and the embodiments of the present application do not limit this.

[0108] Further optionally, the current detection circuit 53 is connected with each on-off control module 511, and configured to output the current value of the three-phase current between the motor 1 and the three-phase inverter 2 to each on-off control module 511. Correspondingly, the on-off control module 511 is also configured to disconnect the phase current output end and the three-phase inverter 2 connected with the on-off control module 511 in the case that the three-phase inverter 2 has a control fault and the current value of any phase current detected by the current detection circuit 53 exceeds the current threshold.

[0109] Specifically optionally, in the on-off control circuit 51, in the case that the three-phase inverter 2 has a control fault and the current value of any phase current detected by the current detection circuit 53 exceeds the current threshold, at least two on-off control modules 511 disconnect the phase current output end and the three-phase inverter 2 connected with the on-off control modules 511.​

[0110] For example, three current detection modules 531 are connected to each of the on-off control modules 511. Each of the current detection modules 531 is configured to detect a current value of a phase current outputted by the connected phase current output terminal, and output the detected current value of the phase current to each of the on-off control modules 511. In the on-off control circuit 51, in a case where a control fault exists in the three-phase inverter 2, and the current value of any phase current exceeds the current threshold value detected by the current detection circuit 53, each of the on-off control modules 511 disconnects the connected phase current output terminal and the three-phase inverter 2.

[0111] In some embodiments of the present application, as shown in Figure 8 The motor protection circuit 5 further comprises a protection control circuit 52.

[0112] The protection control circuit 52 is connected to the three-phase inverter 2 and the on-off control circuit 51. The protection control circuit 52 is configured to control the on-off control circuit 51 to disconnect at least two phase current output terminals of the three-phase inverter 2 and the motor 1 in a case where it is determined that a control fault exists in the three-phase inverter 2.

[0113] Optionally, the protection control circuit 52 can be configured to control the on-off control circuit 51 to disconnect any two phase current output terminals of the three-phase inverter 2 and the motor 1, or control the on-off control circuit 51 to disconnect all three phase current output terminals of the three-phase inverter 2 and the motor 1 in a case where it is determined that a control fault exists in the three-phase inverter 2. Correspondingly, the protection control circuit 52 is configured to control the on-off control circuit 51 to connect all three phase current output terminals of the three-phase inverter 2 and the motor 1 in a case where it is determined that a control fault does not exist in the three-phase inverter 2.

[0114] In some embodiments of the present application, as previously described, the control fault of the three-phase inverter 2 can be caused by a fault of the three-phase inverter 2 itself, resulting in an uncontrolled control fault of the three-phase inverter 2. Alternatively, the control fault of the three-phase inverter 2 can be caused by a fault of a motor control circuit used to control the three-phase inverter 2, resulting in an uncontrolled control fault of the three-phase inverter 2.

[0115] Based on this, the protection control circuit 52 can be connected to the three-phase inverter 2 through the motor control circuit. The protection control circuit 52 can be further configured to determine that a control fault exists in the three-phase inverter 2 in a case where it is determined that a fault exists in the three-phase inverter 2, or a fault exists in the motor control circuit.

[0116] In an alternative case, the protection control circuit 52 can be configured to actively monitor the working status of the three-phase inverter 2 and the motor control circuit to determine whether the three-phase inverter 2 or the motor control circuit has a fault, and then determine that the three-phase inverter 2 has a control fault, and the on-off control circuit 51 disconnects at least two phase current output terminals of the three-phase inverter 2 and the motor 1.

[0117] In some embodiments, the three-phase inverter 2 includes power switch tubes. The motor 1 is powered by the battery pack 4 through the power switch tubes.

[0118] The protection control circuit 52 can be configured to determine that the three-phase inverter 2 has a fault when at least one power switch tube in the three-phase inverter 2 is short-circuited. Alternatively, the protection control circuit 52 can be connected with each power switch tube in the three-phase inverter 2 to monitor whether each power switch tube is short-circuited. In an alternative implementation, the protection control circuit 52 includes a desaturation circuit corresponding to each power switch tube. The desaturation circuit is connected with the corresponding power switch tube to collect the drain-source voltage Vce of the power switch tube, and when the drain-source voltage Vce exceeds a voltage threshold, it indicates that the drain-source current Ids of the power switch tube is too large, the power switch tube is out of the saturation region, and the power switch tube has a short circuit.

[0119] For example, the structure of the three-phase inverter 2 is as shown in the structure of the three-phase inverter 2 described above. Figure 1 The protection control circuit 52 can be connected with each power switch tube in the first bridge arm circuit 21, the second bridge arm circuit 22 and the third bridge arm circuit 23. The protection control circuit 52 is configured to monitor the short circuit condition of each power switch tube.

[0120] In other embodiments, the protection control circuit 52 is also configured to determine that the motor control circuit has a fault when an under-voltage of the motor control circuit is monitored. Alternatively, the protection control circuit 52 can be connected with the motor control circuit to collect the circuit working voltage input by the power supply terminal of the motor control circuit and the on control voltage output by the control output terminal of the motor control circuit, and when the circuit working voltage is less than a first voltage threshold, or the on control voltage is less than a second voltage threshold, it is determined that the motor control circuit has an under-voltage, and it is determined that the motor control circuit has a fault.

[0121] In some embodiments, the protection control circuit 52 can actively monitor the fault condition of the three-phase inverter 2 and the motor control circuit, so as to effectively ensure the accuracy of the fault judgment of the protection control circuit 52 on the three-phase inverter 2 and the motor control circuit, and then facilitate timely control to disconnect the three-phase inverter 2 and the motor 1 when the three-phase inverter 2 or the motor control circuit fails, so that there is no electrical connection loop between the three-phase inverter 2 and the motor 1, effectively preventing the back-EMF current of the motor 1 from being backfilled through the three-phase inverter 2, and solving the device damage problem of the three-phase inverter, the battery pack and other devices connected to the motor due to the back-EMF current.

[0122] In another alternative case, the protection control circuit 52 can be used to passively monitor whether the three-phase inverter 2 or the motor control circuit fails to determine the fault condition of the three-phase inverter 2 and the motor control circuit. Then, in the case of determining that the three-phase inverter 2 or the motor control circuit fails, it is determined that the three-phase inverter 2 has a control fault, and the on-off control circuit 51 is controlled to disconnect at least two phase current output terminals of the three-phase inverter 2 and the motor 1.

[0123] In some embodiments, the motor control circuit is further used to output a target fault signal to the protection control circuit 52 in the case of detecting that the three-phase inverter 2 fails or the motor control circuit fails. Correspondingly, the protection control circuit 52 can be used to control the on-off control circuit 51 to disconnect at least two phase current output terminals of the three-phase inverter 2 and the motor 1 in the case of receiving the target fault signal.

[0124] For example, the motor control circuit includes a motor drive chip. The motor drive chip is used to generate an IPM fault signal (i.e., a target fault signal) and report the IPM fault signal to the protection control circuit 52 in the case of the three-phase inverter 2 failing or the motor control circuit failing. The protection control circuit 52 can be used to control the on-off control circuit 51 to disconnect at least two phase current output terminals of the three-phase inverter 2 and the motor 1 in the case of receiving the IPM fault signal. Correspondingly, the protection control circuit 52 can be used to control the on-off control circuit 51 to connect three phase current output terminals of the three-phase inverter 2 and the motor 1 in the case of not receiving the IPM fault signal.

[0125] In some embodiments, the protection control circuit 52 can reuse the fault detection results of the motor control circuit on the three-phase inverter 2 and its own fault detection results to directly control the on-off control circuit 51 to disconnect at least two phase current output terminals of the three-phase inverter 2 and the motor 1 when a target fault signal indicating that the three-phase inverter 2 or the motor control circuit has a fault is received from the motor control circuit. Compared with the scheme in which the protection control circuit 52 needs to actively monitor whether the three-phase inverter 2 and the motor control circuit have faults, the protection control circuit 52 does not need to have a part of circuit for monitoring faults of the three-phase inverter 2 and the motor control circuit, thereby reducing the circuit area of the protection control circuit 52 and reducing the cost of the protection control circuit 52.

[0126] Further optionally, as shown in Figure 9 The motor protection circuit 5 includes a current detection circuit 53.

[0127] The current detection circuit 53 is connected with the motor 1, the three-phase inverter 2, and the protection control circuit 52. The current detection circuit 53 is configured to detect the current values of the three-phase currents between the motor 1 and the three-phase inverter 2, and output the current values to the protection control circuit 52.

[0128] The protection control circuit 52 is configured to control the on-off control circuit 51 to disconnect at least two phase current output terminals of the three-phase inverter 2 and the motor 1 when it is determined that the three-phase inverter 2 has a control fault and the current value of any phase current exceeds the current threshold.

[0129] Optionally, the protection control circuit 52 can be configured to determine, for each received current value of a phase current, whether the current value of the phase current exceeds the current threshold when it is determined that the three-phase inverter 2 has a control fault, to control the on-off control circuit 51 to disconnect at least two phase current output terminals of the three-phase inverter 2 and the motor 1 when the current value of a phase current exceeds the current threshold, and to control the on-off control circuit 51 to connect three phase current output terminals of the three-phase inverter 2 and the motor 1 when the current values of the three-phase currents do not exceed the current threshold.

[0130] In an optional implementation, the current detection circuit 53 includes three current detection modules 531. Each current detection module 531 is connected with the protection control circuit 52, the three-phase inverter 2, and a different phase current output terminal of the motor 1. Each current detection module 531 is configured to detect the current value of the phase current output by the connected phase current output terminal, and output the current value to the protection control circuit 52.

[0131] Specifically, the three current detection modules 531 include a first current detection module, a second current detection module and a third current detection module. The first current detection module is connected with the protection control circuit 52, the three-phase inverter 2 and the first phase current output terminal of the motor 1, and is configured to detect the current value of the U-phase current output by the motor 1 and output the current value of the U-phase current to the protection control circuit 52. The second current detection module is connected with the protection control circuit 52, the three-phase inverter 2 and the second phase current output terminal of the motor 1, and is configured to detect the current value of the V-phase current output by the motor 1 and output the current value of the V-phase current to the protection control circuit 52. The third current detection module is connected with the protection control circuit 52, the three-phase inverter 2 and the third phase current output terminal of the motor 1, and is configured to detect the current value of the W-phase current output by the motor 1 and output the current value of the W-phase current to the protection control circuit 52. The protection control circuit 52 is configured to control the on-off control circuit 51 to disconnect at least two phase current output terminals of the three-phase inverter 2 and the motor 1 in a case where it is determined that the three-phase inverter 2 has a control fault and the current value of any phase current among the U-phase current, the V-phase current and the W-phase current exceeds the current threshold.

[0132] In some embodiments, the on-off control circuit 51 is configured to connect or disconnect the three-phase inverter 2 and the motor 1 under the control of the protection control circuit 52.

[0133] In an alternative case, the protection control circuit 52 can be a controller. The controller can include a programmable control chip, a Field-Programmable Gate Array (FPGA), a Complex Programmable Logic Device (CPLD) or a Digital Signal Process (DSP) chip, etc. The protection control circuit 52 is configured to output an off control signal to the on-off control circuit 51 in a case where it is determined that the three-phase inverter 2 has a control fault, and output an on control signal to the on-off control circuit 51 in a case where it is determined that the three-phase inverter 2 does not have a control fault. Correspondingly, the on-off control circuit 51 is configured to disconnect at least two phase current output terminals of the three-phase inverter 2 and the motor 1 under the control of the off control signal, and connect three phase current output terminals of the protection control circuit 52 and the motor 1 under the control of the on control signal.

[0134] Further optionally, the protection control circuit 52 is configured to output an off control signal to the on-off control circuit 51 in a case where it is determined that the three-phase inverter 2 has a control fault and the current value of any phase current exceeds the current threshold value; output an on control signal to the on-off control circuit 51 in a case where it is determined that the three-phase inverter 2 has a control fault and the current value of each phase current does not exceed the current threshold value; and output the on control signal to the on-off control circuit 51 in a case where it is determined that the three-phase inverter 2 does not have a control fault. Correspondingly, the on-off control circuit 51 is configured to disconnect the at least two phase current output terminals of the three-phase inverter 2 and the motor 1 under the control of the off control signal; and connect the three phase current output terminals of the protection control circuit 52 and the motor 1 under the control of the on control signal.

[0135] Optionally, the on-off control circuit 51 comprises three on-off control modules 511. The protection control circuit 52 is connected to each on-off control module 511. The protection control circuit 52 is configured to control at least two on-off control modules 511 to disconnect the three-phase inverter 2 and the phase current output terminal connected thereto in a case where it is determined that the three-phase inverter 2 has a control fault.

[0136] Specifically, the three on-off control modules 511 comprise a first on-off control module, a second on-off control module, and a third on-off control module. The first on-off control module is connected to the first phase current output terminal of the motor 1. The first on-off control module is configured to connect or disconnect the first phase current output terminal and the three-phase inverter 2 under the control of the protection control circuit 52. The second on-off control module is connected to the second phase current output terminal of the motor 1. The second on-off control module is configured to connect or disconnect the second phase current output terminal and the three-phase inverter 2 under the control of the protection control circuit 52. The third on-off control module is connected to the third phase current output terminal of the motor 1. The third on-off control module is configured to connect or disconnect the third phase current output terminal and the three-phase inverter 2 under the control of the protection control circuit 52.

[0137] For example, the protection control circuit 52 is configured to control the first on-off control module, the second on-off control module, and the third on-off control module to disconnect the three-phase inverter 2 and the phase current output terminal connected thereto in a case where it is determined that the three-phase inverter 2 has a control fault, so that the three-phase inverter 2 and the three phase current output terminals of the motor 1 are all disconnected in an electrical connection.

[0138] In some embodiments, the on-off control module 511 comprises a switching device S. The switching device S is configured to connect or disconnect the phase current output terminal and the three-phase inverter 2 under the control of the protection control circuit 52.

[0139] For example, the switching device S is a relay. The static contact of the relay can be connected with the three-phase inverter 2, the moving contact can be connected with the phase current output end of the motor 1, and the coil is connected with the protection control circuit 52. The protection control circuit 52 can control the coil of the relay to be powered on, so that the electromagnet drives the moving contact to move, and then the moving contact is connected with the static contact, and the phase current output end and the three-phase inverter 2 are connected. The protection control circuit 52 can also control the coil of the relay to be powered off, so that the electromagnet returns to the original position, the moving contact is disconnected with the static contact, and the phase current output end and the three-phase inverter 2 are disconnected.

[0140] In summary, in the motor protection circuit provided in the embodiment of the application, the on-off control circuit is used to disconnect the three-phase inverter and the motor when it is determined that the three-phase inverter has a control fault, which indicates that the working state of the three-phase inverter is not controlled and the motor protection cannot be implemented by controlling the three-phase inverter. In this way, the electrical connection loop between the three-phase inverter and the motor does not exist, and the backflow of the counter electromotive force current generated by the counter electromotive force of the motor through the three-phase inverter is effectively prevented, and the damage of the three-phase inverter, the battery pack and other devices connected with the motor caused by the counter electromotive force current is solved.

[0141] The embodiment of the application also provides a flowchart of a motor protection method. The motor protection method is applied to the motor protection circuit provided in the embodiment of the application. The motor protection method comprises the following steps.

[0142] In step S10, the on-off control circuit disconnects at least two phase current output ends of the three-phase inverter and the motor when the three-phase inverter has a control fault.

[0143] In an optional implementation, the three-phase inverter works under the control of the motor control circuit. The on-off control circuit can disconnect at least two phase current output ends of the three-phase inverter and the motor when the three-phase inverter has a fault or the motor control circuit that controls the three-phase inverter has a fault.

[0144] In some embodiments, the three-phase inverter comprises a power switch tube. The on-off control circuit can disconnect at least two phase current output ends of the three-phase inverter and the motor when at least one power switch tube is short-circuited, which indicates that the three-phase inverter has a fault. In other embodiments, the on-off control circuit can disconnect at least two phase current output ends of the three-phase inverter and the motor when the motor control circuit has an under-voltage, which indicates that the motor control circuit has a fault.

[0145] In some other embodiments, the motor control circuit is further configured to output a target fault signal in a case where the three-phase inverter is detected to have a fault, or the motor control circuit is detected to have a fault. Accordingly, the on-off control circuit can be configured to disconnect the at least two phase current output terminals of the three-phase inverter and the motor in a case where the motor control circuit outputs the target fault signal, indicating that the three-phase inverter has a control fault.

[0146] In the embodiments of the present application, the motor and the three-phase inverter are connected through the on-off control circuit. The on-off control circuit can be configured to disconnect the three-phase inverter and the motor in a case where it is determined that the three-phase inverter has a control fault, indicating that the working state of the three-phase inverter is not controllable, and the motor protection cannot be implemented by controlling the three-phase inverter, so as to make the three-phase inverter and the motor not have an electrical connection loop, effectively prevent the backflow of the counter electromotive force current generated by the counter electromotive force of the motor through the three-phase inverter, and solve the problem of device damage of the three-phase inverter, the battery pack and other devices connected to the motor due to the counter electromotive force current.

[0147] In some embodiments of the present application, the motor protection circuit further includes a current detection circuit. Based on this option, the on-off control circuit can be further configured to disconnect the at least two phase current output terminals of the three-phase inverter and the motor in a case where it is determined that the three-phase inverter has a control fault, and the current value of any phase current detected by the current detection circuit exceeds the current threshold.

[0148] Optionally, the on-off control circuit includes three on-off control modules. The on-off control circuit can disconnect the phase current output terminals of the three-phase inverter and the motor through at least two on-off control modules in a case where it is determined that the three-phase inverter has a control fault, and the current value of any phase current exceeds the current threshold.

[0149] In some embodiments of the present application, the motor protection circuit includes a protection control circuit. The motor protection method includes:

[0150] In step S20, the protection control circuit controls the on-off control circuit to disconnect the at least two phase current output terminals of the three-phase inverter and the motor in a case where it is determined that the three-phase inverter has a control fault.

[0151] In an optional implementation, the protection control circuit is connected to the three-phase inverter through the motor control circuit. The protection control circuit can determine that the three-phase inverter has a control fault in a case where it is determined that the three-phase inverter has a fault, or the motor control circuit has a fault.

[0152] In some embodiments, the three-phase inverter includes power switch tubes. The protection control circuit can determine that the three-phase inverter has a fault in a case where at least one power switch tube is monitored to have a short circuit. In some other embodiments, the protection control circuit can determine that the motor control circuit has a fault in a case where the motor control circuit is monitored to have an under-voltage.

[0153] In some other embodiments, the motor control circuit is further configured to output a target fault signal to the protection control circuit in a case where the three-phase inverter is detected to have a fault, or the motor control circuit is detected to have a fault. Accordingly, the protection control circuit can determine that the three-phase inverter has a control fault in a case where the target fault signal is received.

[0154] In the embodiments of the present application, the motor is connected to the three-phase inverter through the on-off control circuit. In a case where the protection control circuit determines that the three-phase inverter has a control fault, indicating that the working state of the three-phase inverter is not controlled and the motor protection cannot be implemented by controlling the three-phase inverter, the protection control circuit can control the on-off control circuit to disconnect the protection control circuit and the motor, so that there is no electrical connection loop between the three-phase inverter and the motor, effectively preventing the back electromotive force current generated by the back electromotive force of the motor from being backfilled through the three-phase inverter, and solving the problem of device damage caused by the back electromotive force current of the motor-connected three-phase inverter, battery pack and other devices.

[0155] In some embodiments of the present application, the motor protection circuit further includes a current detection circuit. The protection control circuit can further control the on-off control circuit to disconnect at least two phase current output terminals of the three-phase inverter and the motor in a case where the three-phase inverter is determined to have a control fault and the current value of any phase current exceeds the current threshold.

[0156] Optionally, the on-off control circuit includes three on-off control modules. The protection control circuit can further control at least two on-off control modules in the on-off control circuit to disconnect the phase current output terminals of the protection control circuit and the motor in a case where the three-phase inverter is determined to have a control fault and the current value of any phase current exceeds the current threshold.

[0157] For example, after the motor control circuit and the three-phase inverter are powered on, the motor control circuit controls the power switch tube of the three-phase inverter to orderly switch, so that the motor receives power supply from the battery pack and drives the motor to work. The protection control circuit can perform the motor protection method as shown in Figure 10 .

[0158] In the motor protection method, the protection control circuit can determine whether the IPM fault signal output by the motor control circuit is received during the high-speed rotation of the motor.

[0159] In a case where the IPM fault signal is not received, the protection control circuit can control the on-off control circuit to connect the three-phase inverter and the motor. In a case where the IPM fault signal is received, the protection control circuit acquires the current value of the three-phase current between the motor and the three-phase inverter output by the current detection circuit. And, it is determined whether the current value of any one phase current exceeds the current threshold.

[0160] In a case where the current value of any phase current exceeds the current threshold, the protection control circuit can control the on-off control circuit to disconnect the three-phase inverter and the motor; in a case where the current value of each phase current does not exceed the current threshold, the protection control circuit can control the on-off control circuit to connect the three-phase inverter and the motor.

[0161] In the embodiment of the present application, the motor and the three-phase inverter are connected through the on-off control circuit. In a case where it is determined that the three-phase inverter has a control fault, indicating that the working state of the three-phase inverter is not controlled and the motor protection cannot be implemented by controlling the three-phase inverter, the on-off control circuit can be controlled to disconnect the three-phase inverter and the motor, so that there is no electrical connection loop between the three-phase inverter and the motor, effectively preventing the back-EMF current generated by the motor due to the generation of back-EMF from being backfilled through the three-phase inverter, and solving the problem of device damage of the three-phase inverter, battery pack and other devices connected to the motor due to the back-EMF current.

[0162] The embodiment of the present application also provides a motor power supply system. The motor power supply system includes a motor, a three-phase inverter and any one of the motor protection circuits provided by the embodiment of the present application. In the motor power supply system provided by the embodiment of the present application, the motor protection circuit includes an on-off control circuit. The motor and the three-phase inverter are connected through the on-off control circuit. The on-off control circuit is used to control the on-off control circuit to disconnect the three-phase inverter and the motor in a case where it is determined that the three-phase inverter has a control fault, indicating that the working state of the three-phase inverter is not controlled and the motor protection cannot be implemented by controlling the three-phase inverter, so that there is no electrical connection loop between the three-phase inverter and the motor, effectively preventing the back-EMF current generated by the motor due to the generation of back-EMF from being backfilled through the three-phase inverter, and solving the problem of device damage of the three-phase inverter, battery pack and other devices connected to the motor due to the back-EMF current.

[0163] The embodiment of the present application also provides an electronic device. The electronic device includes any one of the motor power supply systems provided by the embodiment of the present application. In the electronic device provided by the embodiment of the present application, the motor protection circuit in the motor power supply system includes an on-off control circuit. The motor and the three-phase inverter are connected through the on-off control circuit. The on-off control circuit is used to control the on-off control circuit to disconnect the three-phase inverter and the motor in a case where it is determined that the three-phase inverter has a control fault, indicating that the working state of the three-phase inverter is not controlled and the motor protection cannot be implemented by controlling the three-phase inverter, so that there is no electrical connection loop between the three-phase inverter and the motor, effectively preventing the back-EMF current generated by the motor due to the generation of back-EMF from being backfilled through the three-phase inverter, and solving the problem of device damage of the three-phase inverter, battery pack and other devices connected to the motor due to the back-EMF current.

[0164] In the embodiments described above, all or some of the steps can be implemented by software, hardware or firmware, or any combination thereof. When implemented by software, all or some of the steps can be implemented in the form of one or more computer programs. The computer program can be stored in any computer readable medium, and when loaded into a computer system, causes the computer system to perform one or more of the steps of the computer program. The computer readable medium can be a magnetic disk, an optical disk or a solid state drive, or any combination thereof. The computer readable medium can be distributed to computer systems connected by a network, so that the computer programs that constitute the computer programs (which can also be in the form of computer readable medium) can be stored in and executed by the network connected computer systems in a distributed manner.

[0165] It should be noted that, in the present document, the terms such as first and second are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Also, the terms "comprising", "containing" or any other variant thereof are intended to cover a non-exclusive inclusion, so that a process, method, article or apparatus that comprises a list of elements does not only include those elements, but also other elements not expressly listed or inherent to such process, method, article or apparatus. Without more limitations, an element defined by the phrase "comprising a" does not exclude the presence of additional identical elements in the process, method, article or apparatus that includes the element.

[0166] Each of the embodiments in the present specification is described in a related manner, and the same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the difference from other embodiments. For the embodiments of the apparatus, electronic device, computer readable storage medium and computer program product containing instructions thereof, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the part of the method embodiments.

[0167] The above merely provides preferred embodiments of the application, and not for limiting the protective scope of the application. Any modification, equivalent replacement, improvement, etc. made within the principle and technical scope of the application shall fall into the protective scope of the application.

Claims

1. A motor protection circuit, characterized in that, The motor protection circuit (5) includes: an on / off control circuit (51); The on / off control circuit (51) is connected to the three-phase inverter (2) and the motor (1) and is used to disconnect at least two phase current output terminals of the three-phase inverter (2) and the motor (1) in the event of a control fault in the three-phase inverter (2); In the event of a fault in the three-phase inverter (2), the three-phase inverter (2) is subject to a control fault. The motor protection circuit (5) also includes: a current detection circuit (53); The current detection circuit (53) is connected to the motor (1) and the three-phase inverter (2) and is used to detect the current value of the three-phase current between the motor (1) and the three-phase inverter (2); The on / off control circuit (51) is also used to disconnect at least two phase current output terminals of the three-phase inverter (2) and the motor (1) when there is a control fault in the three-phase inverter (2) and the current value of any phase current is detected by the current detection circuit (53) to exceed the current threshold. The three-phase inverter (2) includes a power switch transistor. The on / off control circuit (51) is connected to the motor control circuit and is used to collect the circuit operating voltage input to the power supply terminal of the motor control circuit and the conduction control voltage output from the control output terminal of the motor control circuit. If the circuit operating voltage is less than a first voltage threshold or the conduction control voltage is less than a second voltage threshold, the motor control circuit is determined to be undervoltage. The first voltage threshold is at least the minimum circuit operating voltage at which the motor control circuit can operate normally, and the second voltage threshold is at least the minimum conduction control voltage at which the power switch transistor can conduct. The motor control circuit malfunctions when it is undervoltage.

2. The motor protection circuit according to claim 1, characterized in that, The motor (1) is powered by the battery pack (4) through the power switch tube; the three-phase inverter (2) fails in the event of a short circuit in at least one of the power switch tubes.

3. The motor protection circuit according to claim 1, characterized in that, The motor control circuit is also used to output a target fault signal when a fault is detected in the three-phase inverter (2) or when the motor control circuit itself is faulty; when the motor control circuit outputs the target fault signal, the three-phase inverter (2) has a control fault.

4. The motor protection circuit according to claim 3, characterized in that, The current detection circuit (53) includes: three current detection modules (531); Each of the current detection modules (531) is connected to a different phase current output terminal of the three-phase inverter (2) and the motor (1) to detect the current value of the phase current output by the connected phase current output terminal.

5. The motor protection circuit according to claim 4, characterized in that, The current detection module (531) includes a current sensor; The current sensor is connected to the three-phase inverter (2) and the phase current output terminal, and is used to detect the current value of the phase current output by the connected phase current output terminal.

6. The motor protection circuit according to claim 1, characterized in that, The on / off control circuit (51) includes: three on / off control modules (511); Each of the on / off control modules (511) is connected to a different phase current output terminal of the three-phase inverter (2) and the motor (1), and is used to disconnect the phase current output terminal and the three-phase inverter (2) in the event of a control fault in the three-phase inverter (2).

7. The motor protection circuit according to claim 6, characterized in that, The on / off control module (511) includes: a switching device (S); The switching device (S) is connected to the three-phase inverter (2) and the phase current output terminal, and is used to disconnect the phase current output terminal and the three-phase inverter (2) in the event of a control fault in the three-phase inverter (2).

8. The motor protection circuit according to claim 7, characterized in that, The switching device (S) includes: a relay; The relay is connected to the three-phase inverter (2) and the phase current output terminal, and is used to disconnect the phase current output terminal and the three-phase inverter (2) in the event of a control fault in the three-phase inverter (2).

9. The motor protection circuit according to claim 1, characterized in that, The motor protection circuit (5) also includes: a protection control circuit (52); The protection control circuit (52) is connected to the three-phase inverter (2) and the on / off control circuit (51) and is used to control the on / off control circuit (51) to disconnect at least two phase current output terminals of the three-phase inverter (2) and the motor (1) when it is determined that there is a control fault in the three-phase inverter (2).

10. The motor protection circuit according to any one of claims 3 to 5, characterized in that, The motor protection circuit (5) also includes: a protection control circuit (52); The current detection circuit (53) is connected to the protection control circuit (52) and is used to output the current value of the three-phase current to the protection control circuit (52); The protection control circuit (52) is connected to the three-phase inverter (2) and the on / off control circuit (51) and is used to control the on / off control circuit (51) to disconnect at least two phase current output terminals of the three-phase inverter (2) and the motor (1) when it is determined that there is a control fault in the three-phase inverter (2) and the current value of any phase current exceeds the current threshold.

11. A motor power supply system, characterized in that, The motor power supply system includes a motor (1), a three-phase inverter (2), and a motor protection circuit (5) as described in any one of claims 1 to 10.

12. An electronic device, characterized in that, The electronic device includes the motor power supply system of claim 11.

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