Motor driving circuit, motor driving device and vehicle

Abstract

The invention provides a motor driving circuit, a motor driving device and a vehicle. The motor driving circuit comprises an H-bridge circuit and a current detection module. The current detection module comprises a processing unit and at least one temperature detection element. The at least one temperature detection element is configured to detect an operating temperature of a switching element in the H-bridge circuit. The processing unit is used for determining the conduction state of the switch elements in the H-bridge circuit according to the voltage difference between the two ends of each switch element in the H-bridge circuit; and determining the current between two nodes for setting the motor according to the conduction state of the switch element in the H-bridge circuit, the working temperature and the voltage difference between the two ends of the switch element. The embodiment of the invention can be applied to an intelligent vehicle or a new energy vehicle, can realize the measurement of the working current of the motor without setting a sampling resistor and an operational amplifier circuit, can reduce the material cost and the layout difficulty of a printed circuit board, and is also beneficial to the accurate judgment and effective response of a system fault.

Description

Technical Field

[0001] The present application relates to the field of smart vehicles, and more specifically, to a motor drive circuit, a motor drive device and a vehicle. Background Art

[0002] With the development of vehicle technology, more and more motors are integrated into vehicles. Monitoring the working current of the motor can be used to determine whether the system is operating normally, and can also implement corresponding response strategies when the system is operating abnormally. In particular, for new energy vehicles such as electric vehicles and hybrid vehicles driven by motors, monitoring the working current of the motor is particularly important.

[0003] In the traditional solution, a sampling resistor is set in series with the motor to achieve high-precision sampling of the motor's operating current. However, when the motor's operating current is large, an additional operational amplifier circuit needs to be added for the sampling resistor, which significantly increases the material cost and increases the system complexity and layout difficulty. Moreover, the motor's operating current obtained based on the traditional solution may cause the system to be unable to identify faults in the drive circuit, and may also lead to misjudgment of the fault. Summary of the invention

[0004] The present application provides a motor drive circuit, a motor drive device and a vehicle, which can realize the measurement of the working circuit of the motor without setting a sampling resistor and an operational amplifier circuit, can reduce material costs, reduce the difficulty of printed circuit board layout, and can reduce the complexity of the system; moreover, it is also conducive to accurate judgment and effective response to system failures.

[0005] In a first aspect, a motor drive circuit is provided. The motor drive circuit includes an H-bridge circuit and a current detection module. The H-bridge circuit includes: a first switch element and a second switch element connected to form a first bridge arm, and a third switch element and a fourth switch element connected to form a second bridge arm. The connection node of the first switch element and the second switch element is a first node, and the connection node of the third switch element and the fourth switch element is a second node, and the first node and the second node are used to set the motor. The H-bridge circuit is used to drive the motor when the first switch element and the fourth switch element are turned on, or when the second switch element and the third switch element are turned on. The current detection module includes a processing unit and at least one temperature detection element. The processing unit is connected to both ends of the first switch element through a first voltage detection circuit, the first voltage detection circuit is used to detect a first voltage difference between both ends of the first switch element; the processing unit is connected to both ends of the second switch element through a second voltage detection circuit, the second voltage detection circuit is used to detect a second voltage difference between both ends of the second switch element; the processing unit is connected to both ends of the third switch element through a third voltage detection circuit, the third voltage detection circuit is used to detect a third voltage difference between both ends of the third switch element; the processing unit is connected to both ends of the fourth switch element through a fourth voltage detection circuit, the fourth voltage detection circuit is used to detect a fourth voltage difference between both ends of the fourth switch element. The at least one temperature detection element is used to: detect the operating temperature of the first switch element to the fourth switch element. The processing unit is used to: determine the conduction state of the first switch element to the fourth switch element according to the first voltage difference to the fourth voltage difference; determine the current between the first node and the second node according to the conduction state and operating temperature of the first switch element to the fourth switch element, and the first voltage difference to the fourth voltage difference.

[0006] In the present application, according to the first voltage difference to the fourth voltage difference, the operating voltage of each switch element can be known, the conduction state of the first switch element to the fourth switch element can be determined, and the flow direction of the current in the circuit can be preliminarily determined; according to the detection result of the operating temperature of the first switch element to the fourth switch element by the temperature detection element, combined with the operating temperature and the operating voltage of the switch element, the operating current of the switch element in series with the motor can be calculated, so that the current between the first node and the second node can be obtained. In this way, since the temperature detection element in the motor drive circuit does not need to be connected in series with the motor, even if the working current of the motor is large, there is no need to worry about the heating of the temperature detection element. The working current of the motor can be measured without setting a sampling resistor in series with the motor and an operational amplifier circuit additionally provided for the sampling resistor, which can reduce material costs, reduce the difficulty of printed circuit board layout, and reduce the complexity of the system; moreover, it is also conducive to accurate judgment and effective response to system failures.

[0007] In some possible implementations, the current detection module may include a first temperature detection element and a second temperature detection element. The distance between the first switch element and the first temperature detection element may be less than a first threshold value, and the distance between one of the second switch element and the third switch element and the first temperature detection element may also be less than the first threshold value. The distance between the fourth switch element and the second temperature detection element may be less than the first threshold value, and the distance between the other of the second switch element and the third switch element and the second temperature detection element may also be less than the first threshold value.

[0008] In the present application, for two switching elements that will not be turned on at the same time under normal circumstances, the same temperature detection element is used to detect the operating temperature of the two switching elements. On the one hand, it can reduce the number of electronic components in the driving circuit, reduce material costs, and reduce wiring difficulty and system complexity; on the other hand, it can avoid the temperature of the temperature detection element from being too high, and ensure the normal operation of the temperature detection element.

[0009] In some possible implementations, the difference between the distance between the first switch element and the first temperature detection element and the distance between the switch element measured by the first temperature detection element and the first temperature detection element among the second switch element and the third switch element may be less than the second threshold. The difference between the distance between the fourth switch element and the second temperature detection element and the distance between the switch element measured by the second temperature detection element and the second temperature detection element among the second switch element and the third switch element may be less than the second threshold.

[0010] In the present application, when the difference in distance between two switching elements measured by the same temperature detection element and the temperature detection element is less than a second threshold value, the temperatures of the two switching elements can evenly affect the temperature measurement results of the temperature detection element, thereby avoiding the situation where the temperature measurement error of the temperature detection element for a certain switching element is much greater than the temperature measurement error for another switching element, thereby improving the accuracy of the measured operating temperature of the switching element.

[0011] In some possible implementations, the first temperature detection element may be disposed between the first switch element and the second switch element, and the second temperature detection element may be disposed between the third switch element and the fourth switch element. Alternatively, the first temperature detection element may be disposed between the first switch element and the third switch element, and the second temperature detection element may be disposed between the second switch element and the fourth switch element.

[0012] In the present application, when a temperature detection element is used to detect the operating temperatures of two switching elements, by arranging the temperature detection element between the two switching elements, it is beneficial to balance the influence of the two switching elements on the operating temperature of the temperature detection element, and it is beneficial to improve the accuracy of the measured operating temperature.

[0013] In some possible implementations, the first temperature detection element, the first switch element, and the switch element of the second switch element and the third switch element whose distance to the first temperature detection element is less than the first threshold value may be arranged on the same layer of the printed circuit board. And / or, the second temperature detection element, the fourth switch element, and the switch element of the second switch element and the third switch element whose distance to the second temperature detection element is less than the first threshold value may be arranged on the same layer of the printed circuit board.

[0014] For multiple switch elements whose temperature is measured by the same temperature detection element, if the multiple switch elements are arranged on different layers of a printed circuit board, even if the distance between the temperature detection element and the multiple switch elements is relatively small, the interlayer structure of the printed circuit board will also play a certain role in heat insulation, which will affect the temperature measurement effect of the temperature detection element. In the present application, by arranging the temperature detection element and the multiple switch elements whose temperature is measured by the temperature detection element on the same layer of the printed circuit board, the accuracy of the measured operating temperature of the switch elements can be improved, thereby improving the accuracy of current detection.

[0015] In some possible implementations, the current detection module may include a third temperature detection element. The distances between the third temperature detection element and the first to fourth switch elements may all be smaller than the first threshold.

[0016] In the present application, the same temperature detection element is used to detect the operating temperatures of the first to fourth switch elements, which can further reduce the number of electronic components, further reduce material costs, and further reduce wiring difficulty and system complexity.

[0017] In some possible implementations, the first to fourth switch elements may surround the third temperature detection element.

[0018] In the present application, when a temperature detection element is used to detect the operating temperatures of four switching elements, by arranging the four switching elements around the temperature detection element, it is helpful to balance the impact of the four switching elements on the operating temperature of the temperature detection element, which is helpful to improve the accuracy of the measured operating temperature.

[0019] In some possible implementations, the first to fourth switch elements and the third temperature detection element may be disposed on the same layer of a printed circuit board.

[0020] In the present application, by arranging the temperature detection element and the multiple switch elements whose temperatures are measured by the temperature detection element on the same layer of the printed circuit board, the accuracy of the measured operating temperature of the switch elements can be improved, thereby improving the accuracy of current detection.

[0021] In some possible implementations, the first threshold is less than or equal to 1 mm.

[0022] In the present application, by setting a smaller first threshold, the temperature measured by the temperature detection element can be directly used as the operating temperature of the switching element under test, thereby ensuring the accuracy of current measurement while reducing the complexity of the system.

[0023] In some possible implementations, the processing unit may also be configured to: limit the use of the motor when the temperature of at least one of the first to fourth switching elements exceeds a third threshold.

[0024] In the present application, when the temperature of any of the first to fourth switching elements exceeds the third threshold, the use of the motor is restricted, which is beneficial to protecting the drive circuit from being damaged due to excessive temperature.

[0025] In some possible implementations, the processing unit may also be used to: limit the use of the motor when an increase in the operating temperature of at least one of the first to fourth switching elements within a first time period exceeds a fourth threshold.

[0026] In the present application, when the temperature increase of any switching element from the first switching element to the fourth switching element within the first time period exceeds the fourth threshold value, limiting the use of the motor can avoid damage to the switching elements due to excessive temperature rise, which is beneficial to ensuring the life of the motor drive circuit.

[0027] In some possible implementations, at least one temperature detection element may include a thermistor, the current detection module may include a power supply circuit of the thermistor, and at least one of the two ends of the thermistor is provided with a voltage detection point. The processing unit may be used to: determine the resistance of the thermistor according to the voltage at the voltage detection point; determine the operating temperature of the thermistor according to the resistance of the thermistor and the corresponding relationship between the resistance of the thermistor and the operating temperature; determine the operating temperature of the switch element measured by the thermistor according to the operating temperature of the thermistor.

[0028] In some possible implementations, the thermal element includes a thermistor.

[0029] In some possible implementations, the thermal element may include a thermal diode, and the power supply circuit of the thermal diode may include a constant current source connected in series with the thermal diode.

[0030] In a second aspect, a motor driving device is provided, which may include the motor driving circuit in the first aspect and any possible implementation manner thereof.

[0031] In a third aspect, a vehicle is provided. The vehicle may include the motor drive circuit of the first aspect and any possible implementation thereof, or may include the motor drive device of the first aspect and any possible implementation thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic diagram of a motor drive circuit provided in an embodiment of the present application;

[0033] Figure 2 is a schematic diagram of another motor drive circuit provided in an embodiment of the present application;

[0034] Figure 3 is a schematic diagram of another motor drive circuit provided in an embodiment of the present application;

[0035] Figure 4 is a schematic diagram of another motor drive circuit provided in an embodiment of the present application;

[0036] Figure 5 is a schematic diagram of a temperature detection circuit provided in an embodiment of the present application;

[0037] Figure 6 is a schematic diagram of another temperature detection circuit provided in an embodiment of the present application;

[0038] Figure 7 is a schematic diagram of another motor drive circuit provided in an embodiment of the present application;

[0039] Figure 8 is a schematic diagram of another motor drive circuit provided in an embodiment of the present application;

[0040] Fig. 9 is a schematic diagram of the positional relationship between the thermal diode and the switch element to be tested provided in an embodiment of the present application;

[0041] Fig.10 It is a schematic diagram of another motor drive circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0042] The technical solution in this application will be described below in conjunction with the accompanying drawings.

[0043] Vehicles include various motors, such as window motors, rearview mirror folding motors, etc. In particular, for new energy vehicles such as electric vehicles and hybrid vehicles, drive motors can be used to provide driving force for the vehicle; and, as an energy conversion device, the drive motor can also provide braking force for new energy vehicles such as electric vehicles and hybrid vehicles in certain scenarios. For example, if the drive motor supports the energy recovery function, the energy recovery function can be used to provide braking force for the vehicle.

[0044] Exemplarily, in order to supply power to the motor, the vehicle may be provided with a drive circuit for the motor (also referred to as a motor drive circuit).

[0045] The H-bridge circuit has the characteristics of simple structure, wide application range and rich functions, and is widely used in motor drive circuits. Figures 1 to 3 An exemplary description is given of a motor drive circuit using an H-bridge circuit.

[0046] For example, Figure 1 is a schematic diagram of a motor drive circuit provided in an embodiment of the present application. Figure 1 In the embodiment, the driving circuit 10 can use an H-bridge circuit to power the motor 15; accordingly, the driving circuit 10 can also be called a motor driving circuit 10, an H-bridge circuit 10 or a circuit 10.

[0047] Reference Figure 1 In the embodiment, the H-bridge circuit 10 may include: a bridge arm 11 formed by switch elements Q1 and Q2, and a bridge arm 12 formed by switch elements Q3 and Q4. The connection node of the switch elements Q1 and Q2 is a node 13; the connection node of the switch elements Q3 and Q4 is a node 14, and the motor 15 may be arranged between the nodes 13 and 14, and may be connected to the nodes 13 and 14.

[0048] When a pair of switch elements at diagonal positions in the H-bridge circuit 10 are in the on state, the two ends of the motor 15 can be connected to the power supply (denoted as Vcc) and the ground wire respectively; at this time, the H-bridge circuit 10 will supply power to the motor 15, and the motor 15 will be driven. For example, when the switch elements Q1 and Q4 are turned on, the current will flow from the power supply Vcc through the switch element Q1, the motor 15 and the switch element Q4 in sequence, and then flow to the ground wire. For another example, when the switch elements Q2 and Q3 are turned on, the circuit will flow from the power supply VCC through the switch element Q3, the motor 15 and the switch element Q2 in sequence, and then flow to the ground wire. In these two modes, the rotation direction of the motor 15 can be opposite.

[0049] For the sake of distinction, the control signals for controlling the on and off of the switch elements Q1 to Q4 may be respectively recorded as control signal 1 to control signal 4. In some implementations, control signal 1 and control signal 2 may be the same signal; control signal 3 and control signal 4 may be the same signal.

[0050] In an example, Figure 1 As shown, the switch elements Q1 to Q4 may be metal-oxide-semiconductor field-effect transistors (MOSFETs), which may be referred to as MOS transistors.

[0051] In another example, the switch elements Q1 to Q4 may be switch elements such as bipolar transistors and triodes.

[0052] In actual scenarios, in order to improve the safety and reliability of the system, it is usually necessary to monitor the operating status of the drive circuit so as to promptly learn about the faults in the drive circuit and respond to the faults quickly. Accordingly, one or more detection modules can be set on the basis of the H-bridge circuit to monitor the operating status of relevant components in the circuit (such as switch elements, loads).

[0053] The following combination Figure 2 and Figure 3 As an example, Figure 2 and Figure 3 The motor driving circuit shown may be an extension or deformation of the driving circuit 10 ; it can be understood that a corresponding detection module is added on the basis of the driving circuit 10 .

[0054] For example, Figure 2 It is a schematic diagram of another motor drive circuit provided in an embodiment of the present application.

[0055] like Figure 2 As shown, the driving circuit 20 may include an H-bridge circuit 10 ; the driving circuit 20 may further include voltage detection modules 21 to 24 to monitor the voltages of the switch elements Q1 to Q4 , respectively.

[0056] Taking the voltage detection module 21 as an example, the voltage detection module 21 may include an operational amplifier circuit A1, and the two output ends of the operational amplifier circuit A1 may be connected to the two ends of the switch element Q1, and the operating voltage of the switch element Q1 may be obtained through the operational amplifier circuit A1. Similarly, the voltage detection modules 22 to 24 may include operational amplifier circuits A2 to A4, respectively. Further, according to the operating voltage of the switch element, it can be determined whether the drive circuit is working normally, and it can be determined whether the drive circuit can normally supply power to the motor 15.

[0057] For example, when the switch element is a MOS tube, the operating voltage of the switch element may refer to the voltage between the drain and source of the MOS tube; accordingly, the operating voltage may be recorded as VDS. Assuming that the switch elements Q1 to Q4 are all MOS tube switches, their operating voltages may be recorded as VDS1 to VDS4, respectively.

[0058] For example, Figure 3 It is a schematic diagram of another motor drive circuit provided in an embodiment of the present application.

[0059] like Figure 3 As shown in (a), the drive circuit 30 may include an H-bridge circuit 10; the drive circuit 30 may also include a current detection module 31 to monitor the working current of the motor 15. The current detection module 31 may include a resistor R0 connected in series with the motor 15. The current flowing through the resistor R0 may be determined based on the working voltage of the resistor R0 and the resistance value of the resistor R0; since the resistor R0 is connected in series with the motor 15, the specific value of the working current of the motor 15 may be obtained. The resistor R0 may also be called a sampling resistor.

[0060] To improve the accuracy of current detection, the current detection module 31 may further include an operational amplifier circuit A5. For example, the resistor R0 may be disposed between the motor 15 and the node 14, and the two input terminals of the operational amplifier circuit A5 may be connected to the two ends of the resistor R0 to obtain the operating voltage of the resistor R0.

[0061] For the current detection module 31, when the working current of the motor is very large (such as the drive motor of electric vehicles and hybrid electric vehicles, etc.), on the one hand, a low-resistance sampling resistor is needed to reduce heat generation; on the other hand, if a low-resistance sampling resistor is used, in order to improve the accuracy of current detection, the operational amplifier circuit A5 is indispensable. This current detection method requires adding more electronic components to the motor drive circuit, which greatly increases the material cost and the difficulty of PCB layout, resulting in an increase in the complexity of system design; moreover, the increase in the number of electronic components may also lead to a decrease in the yield rate of the entire system.

[0062] In addition, for possible faults in the circuit, the detection result of the current detection module 31 may not be able to detect the existence of a fault in the circuit 30, and may even mislead the form of the fault. For example, assuming that the node 14 is short-circuited to the ground, the equivalent circuit of the fault can be as follows: Figure 3As shown in (b) in FIG. 1 . When the switch elements Q1 and Q4 are turned on, the current can flow normally through the motor because the node 14 is short-circuited to the ground; in this case, according to the working current of the motor detected by the current detection module 31, it may be mistakenly believed that the circuit is still in a normal state. When the switch elements Q2 and Q3 are turned on, because the node 14 is short-circuited to the ground, the current will flow from the power supply Vcc through the switch element Q3 and then through the node 14 to the ground; in this case, the current detection module 31 will not detect the working current of the motor, and may mistakenly determine that the drive circuit 30 is open.

[0063] In view of this, an embodiment of the present application provides a motor drive circuit that can accurately detect the operating current of the motor while also facilitating accurate judgment of potential circuit faults.

[0064] For example, Figure 4 Schematic diagram of a motor drive circuit provided in an embodiment of the present application. Figure 4 As shown, the motor driving circuit 40 may include an H-bridge circuit 41 and a current detection module 42 .

[0065] The H-bridge circuit 41 may include a first switch element and a second switch element connected to form a first bridge arm, and a third switch element and a fourth switch element connected to form a second bridge arm. The connection node of the first switch element and the second switch element is a first node, and the connection node of the third switch element and the fourth switch element is a second node. The first node and the second node may be used to set the motor 41; the motor 43 may be connected to the first node and the second node. The H-bridge circuit 41 may be used to: drive the motor 43 when the first switch element and the fourth switch element are turned on; or, drive the motor 43 when the second switch element and the third switch element are turned on.

[0066] In some embodiments, Figure 1 The H-bridge circuit 10 shown can be used as an example of an H-bridge circuit 41. For example, the bridge arm 11 can correspond to the first bridge arm, the node 13 can correspond to the first node, the switch elements Q1 and Q2 can correspond to the first switch element and the second switch element respectively; accordingly, the bridge arm 12 can correspond to the second bridge arm, the node 14 can correspond to the second node, and the switch elements Q3 and Q4 can correspond to the third switch element and the fourth switch element respectively. For another example, the bridge arm 12 can correspond to the first bridge arm, the node 14 can correspond to the first node; accordingly, the bridge arm 11 can correspond to the first bridge arm, and the node 13 can correspond to the second node.

[0067] The current detection module 42 may include a processing unit 44 and at least one temperature detection element, such as temperature detection elements 1 to n (n is a positive integer).

[0068] The processing unit 44 can be connected to both ends of the first switch element to the fourth switch element through the voltage detection circuits 45 to 48, respectively, to obtain the voltage difference between the first switch element and the fourth switch element. For example, the processing unit 44 can be connected to both ends of the first switch element through the voltage detection circuit 45 to obtain the voltage difference between the first switch element; the connection method of the voltage detection circuits 46 to 48 is similar. For the convenience of distinction, the voltage difference between the two ends of the first switch element is recorded as the first voltage difference; similarly, the voltage difference between the two ends of the second switch element to the fourth switch element is recorded as the second voltage difference to the fourth voltage difference.

[0069] The at least one temperature detection element can be used to detect the operating temperature of the first to fourth switch elements. The processing unit 44 can be used to determine the conduction state of the first to fourth switch elements according to the first to fourth voltage differences; and determine the operating current of the motor 43 according to the conduction state and the operating temperature of the first to fourth switch elements and the first to fourth voltage differences.

[0070] For example, according to the operating temperature of the switch element, the operating resistance of the switch element can be determined according to the corresponding relationship between the temperature and the resistance of the switch element. The voltage difference across a switch can also be called the operating voltage of the switch element; when the switch element is turned on, the magnitude of the current passing through the switch element can be determined according to the operating resistance and the operating voltage of the switch element. Combined with the conduction conditions of each switch element, the magnitude of the current flowing through the motor can be determined.

[0071] In one example, it is assumed that based on the operating voltage of each switch element, it is known that the second switch element and the third switch element are in the on state, and the first switch element and the fourth switch element are in the off state. In this case, based on the conduction status of each switch element, it can be known that the current flows to the motor 43 through the third switch element, and then flows to the second switch element. Further, the operating current of the motor can be determined based on the operating current of the second switch element and / or the third switch. For example, the calculated operating current of the second switch element can be directly determined as the operating current of the motor. For another example, the calculated operating current of the third switch element can be directly used as the operating current of the motor. For another example, the average value of the calculated operating currents of the second switch element and the third switch element can be used as the operating current of the motor.

[0072] In another example, it is assumed that based on the operating voltage of each switch element, it is known that the third switch element is in the on state, and the first switch element, the second switch element, and the fourth switch element are in the off state. In this case, if the operating current of the third switch element is much greater than the normal operating current, it can be considered that no current passes through the motor 43, and it can be considered that there is a short circuit with the ground near the second node.

[0073] For example, suppose Figure 1 The switching elements Q1 to Q4 in the circuit 40 correspond to the first to fourth switching elements in the circuit 40, respectively. Figure 3 In the case of a short-circuit fault as shown in (b) in FIG. 1 , the current detection module 42 can accurately determine that a short-circuit to ground fault exists at the corresponding node 14 .

[0074] In the embodiment of the present application, the conduction state of the first to fourth switch elements is determined according to the working voltage of the switch element, and the flow direction of the current in the circuit can be preliminarily determined; according to the detection result of the working temperature of the first to fourth switch elements by the temperature detection element, combined with the working temperature and working voltage of the switch element, the working current of the switch element connected in series with the motor can be calculated, so that the working current of the motor can be obtained. In this way, since the temperature detection element in the motor drive circuit does not need to be connected in series with the motor, even if the working current of the motor is large, there is no need to worry about the heating of the temperature detection element. The working current of the motor can be measured without setting a sampling resistor connected in series with the motor and an additional operational amplifier circuit for the sampling resistor, which can reduce material costs, reduce the difficulty of printed circuit board layout, and reduce the complexity of the system; moreover, it is also conducive to accurate judgment and effective response to system failures.

[0075] In some possible implementations, the temperature detection element in the motor drive circuit may include a thermistor, such as a thermistor diode, a thermistor, etc. The current detection module may include a power supply circuit for the thermistor, and at least one of the two ends of the thermistor may be provided with a voltage detection point. The processing unit 44 may be used to: determine the resistance of the thermistor according to the voltage at the voltage detection point; determine the operating temperature of the thermistor according to the resistance of the thermistor and the corresponding relationship between the resistance of the thermistor and the operating temperature; determine the operating temperature of the switch element measured by the thermistor according to the operating temperature of the thermistor.

[0076] The following combination Figure 5 and Figure 6 , an exemplary description is given of the arrangement of thermistors in a motor drive circuit.

[0077] For example, Figure 5 is a schematic diagram of a temperature detection circuit provided in an embodiment of the present application. Figure 5 In the embodiment, it is assumed that the thermistor element used for temperature detection is a thermal diode.

[0078] like Figure 5As shown, the temperature detection circuit 300 may include a thermistor 310 and a constant current source 320; the constant current source 320 may be connected in series with the thermistor 310. The temperature detection circuit 300 may also include a voltage detection point 330 disposed between the thermistor 310 and the constant current source 320. The thermistor 310 and any switch element in the H-bridge circuit (in Figure 5 China-Israel Q m The distance between the thermal diode 310 and the thermal diode 310 may be less than or equal to a certain threshold value (represented as the first threshold value for easy distinction). Figure 4 Any one of the temperature detection elements 1 to n in.

[0079] In one embodiment, referring to Figure 5 In (a), one end of the thermistor 310 can be connected to the constant current source 320, and the other end can be grounded; the other end of the constant current source 320 can be connected to a power source (for easy distinction, denoted as Vcc2). For example, since one end of the thermistor 310 is grounded, the voltage measured at the voltage detection point 330 can be used as the operating voltage of the thermistor 310; the resistance of the thermistor 310 can be determined based on the operating current of the constant current source 320 and the operating voltage of the thermistor 310; based on the corresponding relationship between the resistance and temperature of the thermistor 310, the operating temperature of the thermistor 310 can be known.

[0080] In another embodiment, referring to Figure 5 In (b), one end of the thermistor diode 310 can be connected to the constant current source 320, and the other end can be connected to the power source Vcc2; the other end of the constant current source 320 can be grounded. For example, assuming that the power source Vcc2 is 3.3V, the difference between the voltage value of the power source Vcc2 and the voltage measured at the voltage detection point 330 is the operating voltage of the thermistor diode 310; Figure 5 Similar to (a) in FIG. 1 , the operating temperature of the thermistor 310 can be calculated based on the corresponding relationship between the operating current of the constant current source 320 , the operating voltage of the thermistor 310 , and the resistance and temperature of the thermistor 310 .

[0081] In another embodiment, the temperature detection circuit 300 may further include a protection resistor 340. Figure 5 (c) in Figure 5 Similar to (a) in FIG. 1 , one end of the constant current source 320 can be connected to the power source Vcc2, and the other end of the constant current source 320 can be connected to the thermistor diode 310; Figure 5 The difference from (a) in FIG. 1 is that the other end of the thermistor diode 310 can be connected to the protection resistor 340, and the other end of the protection resistor 340 can be grounded. Figure 5In (c), the thermistor diode 310 is no longer directly grounded, but is connected to the ground wire through the protection resistor 340. For another example, in order to obtain the working voltage of the thermistor diode 310, a voltage detection point 350 can be added to the temperature detection circuit. The voltage detection points 350 and 330 can be located at both ends of the thermistor diode 310, respectively. Figure 5 As shown in (c) in .

[0082] For example, Figure 6 is a schematic diagram of another temperature detection circuit provided in an embodiment of the present application. Figure 6 In the embodiment, it is assumed that the thermal element used for temperature detection is a thermistor.

[0083] The temperature detection circuit 400 may include a thermistor 410 and a protection resistor 420; the protection resistor 420 may be connected in series with the thermistor 410. The temperature detection circuit 400 may also include a voltage detection point 430 disposed between the thermistor 410 and the protection resistor 420. The thermistor 410 and any switch element in the H-bridge circuit (in Figure 6 China-Israel Q m The distance between the thermistor 410 and the Figure 4 Any one of the temperature detection elements 1 to n in.

[0084] In one embodiment, referring to Figure 6 In (a), one end of the thermistor 410 can be connected to the protection resistor 420, and the other end can be grounded; the other end of the protection resistor 420 can be connected to the power supply Vcc2. For example, since one end of the thermistor 410 is grounded, the voltage value measured at the voltage detection point 430 can be used as the voltage division of the thermistor 410 in the circuit; the difference between the power supply Vcc2 and the voltage value measured at the voltage detection point 430 is the voltage division of the protection resistor 420 in the circuit. According to the voltage division of the protection resistor 420 and the resistance value of the resistor, the working current of the thermistor 410 can be calculated; according to the working current and the voltage division of the thermistor 410, the resistance value of the thermistor 410 can be calculated; based on the corresponding relationship between the resistance value of the thermistor 410 and the temperature, the working temperature of the thermistor 410 can be known.

[0085] In another embodiment, referring to Figure 6In (b), one end of the thermistor 410 can be connected to the protection resistor 420, and the other end can be connected to the power supply Vcc2; the other end of the protection resistor 420 can be grounded. For example, the difference between the power supply Vcc2 and the voltage value measured at the voltage detection point 430 is the voltage division of the thermistor 410 in the circuit; the difference between the voltage values ​​measured at the voltage detection point 430 is the voltage division of the protection resistor 420 in the circuit. According to the voltage division of the two resistors in the circuit, the resistance value of the protection resistor 420, and the corresponding relationship between the resistance value of the thermistor and the temperature, the operating temperature of the thermistor 410 can be determined.

[0086] It is understandable that the circuit 400 may also include other electronic components such as resistors / diodes; when the other end of the thermistor 410 is no longer connected to the power supply Vcc2 and the ground line, but is connected to other electronic components other than the protection resistor 420, voltage detection points may be set at both ends of the thermistor 410. For example, Figure 6 As shown in (c) in FIG. 4 , a voltage detection point 450 may be provided at the other end of the thermistor 410 .

[0087] Combination of the above Figure 5 and Figure 6 The temperature detection method of temperature detection is exemplified; the specific implementation of the temperature detection element is not limited to Figure 5 and Figure 6 For example, you can Figure 5 The thermistor is replaced by a thermistor.

[0088] For example, in the motor driving circuit 40 , a single temperature detection element may be used to detect the operating temperature of one or more switching elements.

[0089] In some possible implementations, in the motor driving circuit 40 , a separate temperature detection element may be provided for each switching element to independently detect the temperature of each switching element.

[0090] In some possible implementations, two temperature detection elements, such as a first temperature detection element and a second temperature detection element, may be provided in the motor drive circuit 40. Among them, the distance between the first switch element and the first temperature detection element may be less than the first threshold value, and the distance between one of the second switch element and the third switch element and the first temperature detection element may be less than the first threshold value. The distance between the fourth switch element and the second temperature detection element may be less than the first threshold value, and the distance between the other switch element of the second switch element and the third switch element and the first temperature detection element may be less than the first threshold value. For example, when the distance between the temperature detection element and the switch element being measured is less than or equal to 0.6 millimeters (millimeter, mm), the temperature measured by the temperature element can be used as the operating temperature of the switch element being measured. For another example, when the distance between the temperature detection element and the switch element being measured is less than or equal to 1 mm, although there will be an error between the temperature of the temperature detection element and the operating temperature of the switch element being measured, the error can still be within an acceptable range.

[0091] In one example, a temperature detection element (such as a first temperature detection element) can be used to detect the operating temperatures of the first switching element and the second switching element, and another temperature detection element (such as a second temperature detection element) can be used to detect the operating temperatures of the third switching element and the fourth switching element.

[0092] Since the first switch element and the second switch element are not turned on at the same time, and the third switch element and the fourth switch element are not turned on at the same time under normal circumstances, this method can not only prevent the temperature of a single temperature detection element from being too high, but also reduce the number of temperature detection elements used and the related wiring.

[0093] In another example, since under normal circumstances the first switch element and the third switch element will not be turned on at the same time and the second switch element and the fourth switch element will not be turned on at the same time, one of the temperature detection elements (such as the first temperature detection element) can be used to detect the operating temperature of the first switch element and the third switch element, and another temperature detection element (such as the second temperature detection element) can be used to detect the operating temperature of the second switch element and the fourth switch element.

[0094] In an embodiment of the present application, for two switching elements that will not be turned on at the same time under normal circumstances, the same temperature detection element is used to detect the operating temperature of the two switching elements. On the one hand, it can reduce the number of electronic components in the driving circuit, reduce material costs, and reduce wiring difficulty and system complexity; on the other hand, it can avoid the temperature of the temperature detection element from being too high, and can ensure the normal operation of the temperature detection element.

[0095] In some possible implementations, the difference in distance between a single temperature detection element and the two switch elements whose temperatures are measured by it may be less than or equal to a second threshold. For example, assuming that a first temperature detection element is used to detect the temperatures of a first switch element and a second switch element; the difference between the distance between the first temperature detection element and the first switch element and the distance between the temperature detection element and the second switch element may be less than or equal to a second threshold. For another example, when the difference between the two distances is 0, the temperature measurement errors of the temperature detection element for the two switch elements may be the same; when the difference between the two distances gradually increases, the temperature measurement error of the temperature detection element for the switch element closer to it will be smaller, and the temperature measurement error for the switch element farther away from it will be larger; when the difference reaches about 0.4 mm, it will have a greater impact on the accuracy of the temperature measurement. For example, the second threshold may be 0.2 mm or 0.3 mm.

[0096] In an embodiment of the present application, when the difference in distance between two switching elements measured by the same temperature detection element and the temperature detection element is less than a second threshold value, the temperatures of the two switching elements can evenly affect the temperature measurement results of the temperature detection element, thereby avoiding the situation where the temperature measurement error of the temperature detection element for a certain switching element is much greater than the temperature measurement error for another switching element, thereby improving the accuracy of the measured operating temperature of the switching element.

[0097] Assume that the first temperature detection element and the second temperature detection element are thermal diodes, and assume that the power supply circuit of the thermal diode adopts Figure 5 The method shown in (a) is combined with Figure 7 and Figure 8 For illustrative purposes only.

[0098] For example, Figure 7 is a schematic diagram of another motor drive circuit provided in an embodiment of the present application. The motor drive circuit 50 can be understood as an expansion or deformation of the circuit 40. Figure 7 In order to facilitate distinction, the power supply of the motor 15 is recorded as Vcc1; the power supply voltage of the thermal diode is recorded as Vcc2.

[0099] Reference Figure 7 ,and Figure 2 The circuits shown are the same, and the driving circuit 50 may be provided with switching elements Q1 to Q4 and may also be provided with operational amplifiers A1 to A4.

[0100] The driving circuit 50 may further include a temperature detection module 510 and a temperature detection module 520. The temperature detection module 510 may be used to detect the operating temperature of the switching elements Q1 and Q2; the temperature detection module 520 may be used to detect the operating temperature of the switching elements Q3 and Q4.

[0101] The temperature detection module 510 may include a thermistor 511 and a power supply circuit for the thermistor 511; the distance between the thermistor 511 and the switching elements Q1 and Q2 may be less than a certain threshold, so as to accurately detect the operating temperature of the switching elements Q1 and Q2.

[0102] Similarly, the temperature detection module 520 may include a thermistor 521 and a power supply circuit for the thermistor 521; the distance between the thermistor 521 and the switching elements Q3 and Q4 may be less than a certain threshold, thereby being able to accurately detect the operating temperature of the switching elements Q3 and Q4.

[0103] For the switch element Q1, the circuit formed by the circuit 501 and the operational amplifier circuit A1 can connect the processing unit 550 to the two ends of the switch element Q1, and the processing unit 550 can obtain the voltage difference between the two ends of the switch element Q1 through the circuit; the circuit can be used as a voltage detection circuit for the switch element Q1. Similarly, the processing unit 550 can be connected to the output ends of the operational amplifiers A2 to A4 through circuits 502 to 504, respectively, to obtain the voltage difference between the two ends of the switch elements Q1 to Q4, respectively. The processing unit 550 can be connected to the voltage detection point 513 of the temperature detection module 510 through the circuit 505 to determine the operating voltage of the thermistor 511 according to the voltage at the voltage detection point 513.

[0104] Exemplarily, for the processing unit 550, the working resistance of the thermistor 511 can be calculated based on the working voltage of the thermistor 511 and the working current of the constant current source 512; the working temperature of the thermistor 511 can be obtained based on the working resistance and the corresponding relationship between the working temperature of the thermistor 511 and the working resistance. According to the working temperature of the thermistor 511 and the heat transfer relationship between the thermistor 511 and the switching elements Q1 and Q2, the working temperatures of the switching elements Q1 and Q2 can be obtained respectively. The processing unit 550 can be connected to the voltage detection point 523 in the temperature detection module 520 through the circuit 506 to determine the working voltage of the thermistor 521 based on the voltage at the voltage detection point 523, and then obtain the working temperatures of the switching elements Q3 and Q4.

[0105] Assume that the switching element Q1 in the motor driving circuit 50 corresponds to the first switching element in the circuit 40, the switching element Q2 corresponds to the second switching element in the circuit 40, the switching element Q3 corresponds to the third switching element in the circuit 40, and the switching element Q4 corresponds to the fourth switching element in the circuit 40. In this case, the thermistor 511 may correspond to the first temperature detection element, and the thermistor 521 may correspond to the second temperature detection element.

[0106] For example, Figure 8 60 is a schematic diagram of another motor drive circuit provided in an embodiment of the present application. The motor drive circuit 60 can be understood as an expansion or deformation of the circuit 40. Figure 8 In order to facilitate distinction, the power supply voltage of the motor 15 is recorded as Vcc1; the power supply voltage of the thermal diode is recorded as Vcc2.

[0107] Reference Figure 8 ,and Figure 2 The circuits shown are the same, and the driving circuit 60 may be provided with switching elements Q1 to Q4 and may also be provided with operational amplifiers A1 to A4.

[0108] and Figure 7 The same is that the driving circuit 60 includes two temperature detection modules, namely, a temperature detection module 610 and a temperature detection module 620. The temperature detection module 610 may include a thermistor 611 and a power supply circuit for the thermistor 611. Similarly, the temperature detection module 620 may include a thermistor 621 and a power supply circuit for the thermistor 521.

[0109] and Figure 7 The difference is that the temperature detection module 610 is used to detect the operating temperature of the switch elements Q1 and Q3, and the temperature detection module 620 is used to detect the operating temperature of the switch elements Q2 and Q4.

[0110] The temperature detection module 610 may include a thermistor 611 and a power supply circuit for the thermistor 611; the distance between the thermistor 611 and the switching elements Q1 and Q3 may be less than a certain threshold, so that the operating temperature of the switching elements Q1 and Q3 can be accurately detected. The temperature detection module 620 may include a thermistor 621 and a power supply circuit for the thermistor 621; the distance between the thermistor 621 and the switching elements Q2 and Q4 may be less than a certain threshold, so that the operating temperature of the switching elements Q2 and Q4 can be accurately detected.

[0111] The processing unit 650 can be connected to the output ends of operational amplifiers A1 to A4 through circuits 601 to 604 respectively to obtain the operating voltages of switching elements Q1 to Q4; it can also be connected to voltage detection points 613 and 623 in temperature detection modules 610 and 620 respectively through circuits 605 and 606.

[0112] Assume that the switching element Q1 in the motor driving circuit 60 corresponds to the first switching element in the circuit 40, the switching element Q2 corresponds to the second switching element in the circuit 40, the switching element Q3 corresponds to the third switching element in the circuit 40, and the switching element Q4 corresponds to the fourth switching element in the circuit 40. In this case, the thermistor 611 may correspond to the first temperature detection element, and the thermistor 621 may correspond to the second temperature detection element.

[0113] In some possible implementations, when a single temperature detection element is used to simultaneously detect the operating temperatures of two switch elements, the temperature detection element may be disposed between the two switch elements. Furthermore, the difference in distance between the temperature detection element and the two switch elements may be less than a certain threshold, or even the distance between the temperature detection element and the two switch elements may be equal.

[0114] For example, the motor drive circuit 50 may be implemented by means of a printed circuit board (PCB); on the printed circuit board, the thermal diode 511 may be located between the switch elements Q1 and Q2, such as Fig. 9 Similarly, the thermal diode 521 may be located between the switching elements Q3 and Q4.

[0115] In the embodiment of the present application, when one temperature detection element is used to detect the operating temperatures of two switching elements, by arranging the temperature detection element between the two switching elements, it is beneficial to balance the influence of the two switching elements on the operating temperature of the temperature detection element, which is beneficial to improving the accuracy of the measured operating temperature.

[0116] In some possible implementations, only one temperature detection element (such as a third temperature detection element) may be provided in the motor drive circuit 40. For example, the distances between the third temperature detection element and the first to fourth switch elements are all less than the first threshold value; in this case, the operating temperatures of the first to fourth switch elements may be detected by the third temperature detection element.

[0117] In the embodiment of the present application, the same temperature detection element is used to detect the operating temperatures of the first switching element to the fourth switching element, which can further reduce the number of electronic components, further reduce material costs, and further reduce wiring difficulty and system complexity.

[0118] Assume that the temperature detection element is a thermal diode, and assume that the power supply circuit of the thermal diode adopts Figure 5 The method shown in (a) is combined with Fig.10 For illustrative purposes only.

[0119] For example, Fig.10 70 is a schematic diagram of another motor drive circuit provided in an embodiment of the present application. The motor drive circuit 70 can be understood as an expansion or deformation of the circuit 40.

[0120] Reference Fig.10 (a) in Figure 2 The circuits shown are the same, and the driving circuit 70 may be provided with switching elements Q1 to Q4 and operational amplifiers A1 to A4.

[0121] The driving circuit 70 may further include a temperature detection module 710. The temperature detection module 710 may be used to detect the operating temperature of the switching elements Q1 to Q4. The temperature detection module 710 may include a thermal diode 711 and a power supply circuit for the thermal diode 711. The distance between the thermal diode 711 and the switching elements Q1 to Q4 may be less than a certain threshold value, so that the operating temperature of the switching elements Q1 to Q4 can be accurately detected.

[0122] and Figure 7 and Figure 8 Similarly, the processing unit 750 can be connected to the output terminals of the operational amplifiers A1 to A4 respectively through the circuits 701 to 704 , and can also be connected to the voltage detection point 713 in the temperature detection module 710 through the circuit 705 .

[0123] For example, by properly arranging the switch elements Q1 to Q4 and the thermal diode on the PCB, the accuracy of the detected temperature can be improved. Fig.10 In (b) and (c), the switching elements Q1 to Q4 can be arranged around the thermal diode 711.

[0124] In some possible implementations, when the same temperature detection element is used to measure the operating temperatures of multiple switch elements, the temperature detection element and the multiple switch elements can be arranged on the same layer of the PCB. Fig. 9 In (a) and (b), for the motor drive circuit 50, the thermal diode 511 and the switch elements Q1 and Q2 can be arranged on the same layer of the PCB; the thermal diode 521 and the switch elements Q3 and Q4 can be arranged on the same layer of the PCB. Fig.10 In (b) and (c), the thermal diode 711 and the switching elements Q1 to Q4 can be arranged on the same layer of the PCB.

[0125] For multiple switch elements whose temperature is measured by the same temperature detection element, if the multiple switch elements are arranged on different layers of the PCB, even if the distance between the temperature detection element and the multiple switch elements is relatively small, the interlayer structure of the PCB will also play a certain role in heat insulation, which will affect the temperature measurement effect of the temperature detection element. In the embodiment of the present application, by setting the temperature detection element and the multiple switch elements whose temperature is measured by the temperature detection element on the same layer of the PCB, the accuracy of the measured operating temperature of the switch element can be improved, thereby improving the accuracy of current detection.

[0126] Exemplarily, according to the operating temperature of the switching element in the motor driving circuit, a temperature protection mechanism may also be set for the motor driving circuit.

[0127] In some possible implementations, the processing unit 44 may also be configured to: limit the use of the motor when the temperature of at least one of the first to fourth switching elements exceeds a third threshold.

[0128] For example, limiting the use of the motor may include at least one of the following: reducing the current output by the power supply to the motor, controlling the H-bridge circuit to disconnect the power supply to the motor, and not responding to instructions for instructing the motor to work within a certain period of time after the motor is powered off.

[0129] Exemplarily, the third threshold value can be a temperature margin added to the operating temperature of each switch element when the motor is working. For example, when the temperature margin is 10 degrees Celsius, it can allow a certain fluctuation in the operating temperature of the switch element and prevent the switch element from being damaged due to excessive temperature. For another example, the temperature margin can be relaxed to 15 degrees Celsius.

[0130] In the embodiment of the present application, when the temperature of any one of the first to fourth switching elements exceeds the third threshold value, the use of the motor is restricted, which is beneficial to protecting the drive circuit from being damaged due to excessive temperature.

[0131] In some possible implementations, the processing unit 44 can also be used to limit the use of the motor when the increase in the operating temperature of at least one of the first to fourth switching elements exceeds a fourth threshold within a certain time period (recorded as the first time period for ease of distinction).

[0132] For example, the first duration may be 3 minutes or 5 minutes, and the fourth threshold may be 10 degrees or 12 degrees. For another example, the first duration and / or the fourth threshold may be set according to the performance of the motor and the specific parameters of the switch element used in the H-bridge circuit.

[0133] In an embodiment of the present application, when the temperature increase of any switching element from the first switching element to the fourth switching element within the first time period exceeds the fourth threshold value, limiting the use of the motor can avoid damage to the switching elements due to excessively rapid temperature rise, which is beneficial to ensuring the life of the motor drive circuit.

[0134] Combination of the above Figures 4 to 10 , an exemplary description is given of the motor drive circuit provided in the embodiments of the present application.

[0135] The present application also provides a motor drive device, which may include the above-mentioned Figures 4 to 10 Any motor drive circuit.

[0136] The embodiment of the present application also provides a vehicle, which may include Figures 4 to 10 Any motor driving circuit, or may include the above-mentioned motor driving device.

[0137] The vehicles involved in the embodiments of the present application may be vehicles in a broad sense, and may be vehicles (such as commercial vehicles, passenger cars, motorcycles, flying cars, trains, etc.), industrial vehicles (such as forklifts, trailers, tractors, etc.), engineering vehicles (such as excavators, bulldozers, cranes, etc.), agricultural equipment (such as mowers, harvesters, etc.), amusement equipment, toy vehicles, etc. The embodiments of the present application do not specifically limit the types of vehicles. For example, the vehicle in the present application may be a hybrid electric vehicle (HEV), a range extended electric vehicle (REEV), a plug-in hybrid electric vehicle (PHEV) or a new energy vehicle (NEV), etc.

[0138] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0139] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0140] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0141] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0142] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0143] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0144] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A motor drive circuit, characterized in that: include: The motor drive circuit includes an H-bridge circuit and a current detection module; The H-bridge circuit comprises: a first switch element and a second switch element connected to form a first bridge arm, and a third switch element and a fourth switch element connected to form a second bridge arm; The connection node between the first switch element and the second switch element is a first node, the connection node between the third switch element and the fourth switch element is a second node, and the first node and the second node are used to set the motor; The H-bridge circuit is used to drive the motor when the first switch element and the fourth switch element are turned on, or when the second switch element and the third switch element are turned on; The current detection module includes a processing unit and at least one temperature detection element; The processing unit is connected to both ends of the first switch element through a first voltage detection circuit, and the first voltage detection circuit is used to detect a first voltage difference between both ends of the first switch element; The processing unit is connected to both ends of the second switch element through a second voltage detection circuit, and the second voltage detection circuit is used to detect a second voltage difference between both ends of the second switch element; The processing unit is connected to both ends of the third switch element through a third voltage detection circuit, and the third voltage detection circuit is used to detect a third voltage difference between both ends of the third switch element; The processing unit is connected to both ends of the fourth switch element through a fourth voltage detection circuit, and the fourth voltage detection circuit is used to detect a fourth voltage difference between both ends of the fourth switch element; The at least one temperature detection element is used to: detect the operating temperatures of the first to fourth switching elements; The processing unit is used for: determining the conduction states of the first switch element to the fourth switch element according to the first voltage difference to the fourth voltage difference; A current between the first node and the second node is determined according to the conduction states and the operating temperature of the first to fourth switching elements and the first to fourth voltage differences.

2. The motor drive circuit according to claim 1, characterized in that: The current detection module includes a first temperature detection element and a second temperature detection element; The distance between the first switch element and the first temperature detection element is smaller than a first threshold, and the distance between one of the second switch element and the third switch element and the first temperature detection element is smaller than the first threshold; The distance between the fourth switching element and the second temperature detection element is smaller than the first threshold, and the distance between the other of the second switching element and the third switching element and the second temperature detection element is smaller than the first threshold.

3. The motor drive circuit according to claim 2, characterized in that: A difference between a distance between the first switch element and the first temperature detection element and a distance between the first temperature detection element and one of the second switch element and the third switch element is smaller than a second threshold; A difference between a distance between the fourth switching element and the second temperature detection element and a distance between the other of the second switching element and the third switching element and the second temperature detection element is smaller than the second threshold value.

4. The motor drive circuit according to claim 2 or 3, characterized in that: The first temperature detection element is arranged between the first switch element and the second switch element, and the second temperature detection element is arranged between the third switch element and the fourth switch element; or, The first temperature detection element is disposed between the first switching element and the third switching element, and the second temperature detection element is disposed between the second switching element and the fourth switching element.

5. The motor drive circuit according to any one of claims 2 to 4, characterized in that: The first temperature detection element, the first switch element, and the switch element of the second switch element and the third switch element whose distance from the first temperature detection element is less than the first threshold value are arranged on the same layer of the printed circuit board; and / or, The second temperature detection element, the fourth switch element, and the switch element of the second switch element and the third switch element whose distance from the second temperature detection element is smaller than the first threshold value are arranged on the same layer of the printed circuit board.

6. The motor drive circuit according to claim 1, characterized in that: The current detection module includes a third temperature detection element; The distances between the third temperature detection element and the first to fourth switch elements are all smaller than a first threshold.

7. The motor drive circuit according to claim 6, characterized in that: The first to fourth switch elements surround the third temperature detection element.

8. The motor drive circuit according to claim 6 or 7, characterized in that: The first to fourth switch elements and the third temperature detection element are arranged on the same layer of a printed circuit board.

9. The motor drive circuit according to any one of claims 2 to 8, characterized in that: The first threshold is less than or equal to 1 mm.

10. The motor drive circuit according to any one of claims 1 to 9, characterized in that: The processing unit is further configured to limit the use of the motor when the operating temperature of at least one of the first to fourth switching elements exceeds a third threshold.

11. The motor drive circuit according to any one of claims 1 to 10, characterized in that: The processing unit is further configured to limit the use of the motor when an increase in the operating temperature of at least one of the first to fourth switching elements within a first time period exceeds a fourth threshold.

12. The motor drive circuit according to any one of claims 1 to 11, characterized in that: The at least one temperature sensing element comprises a thermistor, The current detection module includes a power supply circuit of the thermistor, and at least one of the two ends of the thermistor is provided with a voltage detection point; The processing unit is used for: determining the resistance of the thermistor according to the voltage at the voltage detection point; Determining the operating temperature of the thermistor according to the resistance of the thermistor and the corresponding relationship between the resistance of the thermistor and the operating temperature; The operating temperature of the switching element measured by the thermistor is determined according to the operating temperature of the thermistor.

13. The motor drive circuit according to any one of claims 1 to 12, characterized in that: The thermal element includes a thermistor.

14. The motor drive circuit according to any one of claims 1 to 13, characterized in that: The thermal element comprises a thermal diode, and a power supply circuit of the thermal diode comprises a constant current source connected in series with the thermal diode.

15. A motor drive device, characterized in that: The invention comprises the motor drive circuit according to any one of claims 1 to 14.

16. A vehicle, characterized in that: The motor driving circuit comprises the motor driving circuit as claimed in any one of claims 1 to 14, or the motor driving device as claimed in claim 15.

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