Motor driving device and vehicle-mounted equipment

Abstract

The utility model provides a motor driving device and vehicle-mounted equipment, and the motor driving device comprises a three-phase inverter bridge which is provided with three bridge branches, and the connection points of the upper bridge and the lower bridge of the three bridge branches are connected with the three phase lines of a motor in a one-to-one correspondence manner; the current sampling circuit is provided with three first sampling resistors, and each first sampling resistor is connected between a connection point of an upper bridge and a lower bridge of each bridge branch and each phase line so as to collect phase current on the corresponding phase line; and the controller is respectively connected with each bridge branch and the current sampling circuit so as to control the upper bridge and the lower bridge of the three bridge branches to be alternately conducted according to the phase current on each phase line so as to drive the motor to rotate at a high rotating speed. According to the motor driving device, effective FOC control of the controller is facilitated, and the high-rotating-speed control requirement of the motor can be met.

Description

Technical Field

[0001] This application relates to the field of motor drive technology, and in particular to a motor drive device and vehicle-mounted equipment. Background Technology

[0002] With the advancement of automotive intelligence, vehicles are integrating rotating in-vehicle devices such as flip-up dashboards, sliding screens, and ceiling-mounted screens. These in-vehicle devices use brushless direct current motors (BLDC) as the rotating motors.

[0003] In related technologies, a motor drive device includes a three-phase inverter bridge, a current sampling circuit, and a controller. The current sampling circuit is used to collect the phase current of the brushless DC motor (hereinafter referred to as the motor). The controller is used to provide drive signals to the three-phase inverter bridge during FOC (Field Oriented Control) control to orderly control the conduction state of the upper and lower bridges in the three-phase inverter bridge, thereby converting DC voltage into three-phase AC voltage to drive the motor. For example... Figure 1 As shown, the current sampling circuit 20 of the related technology includes three sampling resistors Rs, which are connected one-to-one between the common terminal of the lower bridge 112 of the three bridge branches 11 in the three-phase inverter bridge 10 and ground. When the lower bridge 112 of each bridge branch 11 is turned on, the current on the M phase line of the motor flows through the corresponding sampling resistor Rs. The phase current can be detected by using the sampling resistor Rs.

[0004] In the process of implementing this application, the inventors discovered that: since the sampling resistor can only collect phase current when the lower bridge of the bridge branch is conducting, the detection of phase current depends on the conduction time of the lower bridge in the bridge branch. However, in high-speed control scenarios, the upper and lower bridges of each bridge branch conduct many times during each round of FOC control, which shortens the conduction time of the lower bridge in the bridge branch. This can easily lead to the inability to correctly collect phase current, and thus the inability to effectively perform FOC control. Therefore, the related technology has the problem that the motor drive device cannot meet the high-speed control requirements of the motor. Utility Model Content

[0005] This application provides a motor drive device and vehicle-mounted equipment to solve the problem that the related technology cannot meet the high-speed control requirements of motors.

[0006] The first aspect of this application provides a motor drive device, comprising:

[0007] The three-phase inverter bridge has three bridge branches, and the connection points of the upper and lower bridges of the three bridge branches are connected one-to-one with the three phase lines of the motor.

[0008] The current sampling circuit has three first sampling resistors, each of which is connected between the connection point of the upper and lower bridges of each bridge branch and each phase line to collect the phase current on the corresponding phase line.

[0009] The controller is connected to each bridge branch and the current sampling circuit respectively, so as to control the upper and lower bridges of the three bridge branches to alternately conduct according to the phase current on each phase line, so as to drive the motor to rotate at high speed.

[0010] In one embodiment, the current sampling circuit further includes:

[0011] The second sampling resistor is connected between the common terminal of the lower bridge of the three bridge branches and ground to collect the total current on the three phase lines;

[0012] The second sampling resistor is connected to the controller to provide the total current to the controller, so that when the total current is greater than the preset current threshold, the controller will control both the upper and lower bridges of the three bridge branches to be cut off.

[0013] In one embodiment, in each bridge branch, the upper bridge includes a first transistor, and the lower bridge includes a second transistor. A first terminal of the first transistor is connected to a first power supply voltage, a second terminal of the first transistor is connected to the first terminal of the second transistor, and a second terminal of the second transistor is grounded. The control terminal of the first transistor is connected to a controller via a first resistor, and the control terminal of the second transistor is connected to the controller via a second resistor. The bridge branch includes at least one of the following:

[0014] The upper bridge includes a first series branch, which includes a third resistor and a first Zener diode connected in series, and the first series branch is connected in parallel with the first resistor;

[0015] The upper bridge includes a second series branch, which includes a fourth resistor and a first capacitor connected in series. The second series branch is connected between the first terminal and the second terminal of the first transistor.

[0016] The lower bridge includes a third series branch, which includes a fifth resistor and a second Zener diode connected in series. The third series branch is connected in parallel with the second resistor.

[0017] The lower bridge includes a fourth series branch, which includes a sixth resistor and a second capacitor connected in series. The fourth series branch is connected between the first and second terminals of the second transistor.

[0018] In one embodiment, the current sampling circuit further includes three current sensing amplifier circuits and a voltage follower circuit. The first input terminal of each current sensing amplifier circuit is connected to the first terminal of each first sampling resistor, and the second input terminal of each current sensing amplifier circuit is connected to the second terminal of each first sampling resistor. The output terminal of each current sensing amplifier circuit is connected to the controller to provide the controller with the voltage difference across the corresponding first sampling resistor, so that the controller determines the corresponding phase current based on the voltage difference. The input terminal of the voltage follower circuit is connected to the second power supply voltage, and the output terminal of the voltage follower circuit is connected to the reference voltage terminal of each of the three current sensing amplifier circuits to provide a reference voltage to each current sensing amplifier circuit.

[0019] And / or, the current sampling circuit also includes three ferrite beads, which are connected one-to-one between the three first sampling resistors and the three phase lines; wherein, the first end of each ferrite bead is grounded through a third capacitor, and the second end of each ferrite bead is grounded through a varistor.

[0020] In one embodiment, the motor drive device further includes at least one of the following:

[0021] The bridge drive circuit is connected between the controller and the three-phase inverter bridge. It is used to amplify the control signal and transmit it to the three-phase inverter bridge. The control signal is used to alternately turn on the upper and lower bridges of the three bridge branches in the three-phase inverter bridge.

[0022] The Hall effect signal detection circuit is used to detect and transmit the rotation angle of the three-phase windings to the controller, so that the controller can control the rotation angle of the motor according to the rotation angle of the three-phase windings.

[0023] In one embodiment, the motor drive device further includes a bridge drive circuit and a power supply module, the power supply module comprising:

[0024] Power supply circuit, used to convert battery power to a fourth power supply voltage;

[0025] A step-down circuit is used to step down the fourth power supply voltage to the third power supply voltage to power the controller and the motor. The third power supply voltage is lower than the fourth power supply voltage.

[0026] A current-limiting circuit is connected between the third power supply voltage and the motor;

[0027] The step-up / step-down circuit is used to boost or step down the fourth power supply voltage to the fifth power supply voltage to power the current sampling circuit and the bridge drive circuit.

[0028] In one implementation, the current limiting circuit includes:

[0029] The source of the third transistor is connected to the first terminal of the seventh resistor, the drain of the third transistor is connected to the power supply terminal of the motor, and the second terminal of the seventh resistor is used to connect to the third power supply voltage.

[0030] The collector of the first transistor is connected to the first end of the eighth resistor, the second end of the eighth resistor is connected to the gate of the third transistor, and a ninth resistor and a fourth capacitor are connected in parallel between the second end of the eighth resistor and the second end of the seventh resistor. The emitter of the first transistor is grounded, and a ninth resistor is connected between the base and emitter of the first transistor. The base of the first transistor is connected to the controller through a tenth resistor.

[0031] The collector of the second transistor is connected to the gate of the third transistor, the emitter of the second transistor is connected to the second end of the seventh resistor, and the base of the second transistor is connected to the first end of the seventh resistor through the twelfth resistor.

[0032] In one embodiment, the current limiting circuit further includes at least one of the following:

[0033] The thirteenth resistor has its first terminal connected to the drain of the third transistor, and its second terminal grounded.

[0034] A π-type filter circuit is connected between the third power supply voltage and the second terminal of the seventh resistor.

[0035] In one embodiment, the power supply circuit is connected to a battery power source via a connector interface, and the power supply circuit includes:

[0036] The interface protection sub-circuit, isolation sub-circuit, reverse connection protection sub-circuit, and filter sub-circuit are connected in sequence; the input terminal of the interface protection sub-circuit is used to connect to the battery power supply, and the output terminal of the filter sub-circuit is used to provide a fourth power supply voltage.

[0037] A second aspect of this application provides an on-board device, including a motor and a motor drive device according to any of the above embodiments, wherein the motor drive device is connected to the motor to drive the motor to rotate.

[0038] The advantages or beneficial effects of the above technical solution include at least the following: Since the three first sampling resistors are connected one-to-one between the connection points of the upper and lower bridges of the three bridge branches and the three phase lines of the motor, when current flows through each phase line of the motor, current also flows through the first sampling resistor connected to the corresponding phase line. This makes the waveform change of the voltage difference formed across each first sampling resistor the same as the waveform change of the current flowing through the corresponding phase line, for example, both being sinusoidal waves, thereby realizing the detection of phase current. This structure allows the detection of phase current to be unaffected by the conduction time of the upper and lower bridges of each bridge branch in the three-phase inverter bridge, which is beneficial for accurately acquiring phase current in high-speed control scenarios. This ensures that the controller controls the upper and lower bridges of the three bridge branches to alternately conduct according to the phase current on each phase line, so as to drive the motor to rotate at high speed. This is beneficial for the controller to perform effective FOC control of the motor, so that the motor drive device meets the high-speed control requirements of the motor. Attached Figure Description

[0039] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. Furthermore, these drawings and textual descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concepts of this application to those skilled in the art through reference to specific embodiments.

[0040] Figure 1 The diagram shows the circuit schematic of a three-phase inverter bridge and a current sampling resistor in related technologies.

[0041] Figure 2 The diagram shown is a structural block diagram of a motor drive device according to an embodiment of this application.

[0042] Figure 3 As shown Figure 2 The circuit diagram of the three-phase inverter bridge and current sampling resistor of the motor drive device.

[0043] Figure 4 The diagram shows the circuit schematic of a current-sensing amplifier and a voltage follower.

[0044] Figure 5 The diagram shows the connection between the first magnetic bead, the first capacitor, and the first varistor and the motor interface, as well as the connection between the third magnetic bead, the second varistor, and the motor interface.

[0045] Figure 6 The diagram shown is a schematic of the Hall signal detection circuit.

[0046] Figure 7 As shown Figure 2 Block diagram of the power supply module.

[0047] Figure 8 As shown Figure 7 The circuit diagram of the medium current limiting circuit.

[0048] Figure 9 As shown Figure 7 The circuit diagram of the power supply circuit. Detailed Implementation

[0049] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this application. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0050] Figure 2 The diagram shown is a structural block diagram of a motor drive device according to an embodiment of this application. Figure 3 As shown Figure 2 The circuit diagram of the three-phase inverter bridge and current sampling resistor of the motor drive device.

[0051] Please refer to the following: Figure 2 and Figure 3 The motor drive device 100 includes a three-phase inverter bridge 10, a current sampling circuit 20, and a controller 30. The three-phase inverter bridge 10 has three bridge branches 11, and the connection points of the upper bridge 111 and lower bridge 112 of each bridge branch 11 are connected to the three phase lines AOUT, BOUT, and COUT of the motor M. The current sampling circuit 20 has three first sampling resistors Rs1, each connected between the connection point of the upper bridge 111 and lower bridge 112 of each bridge branch 11 and the corresponding phase line, to collect the phase current on the corresponding phase line. The controller 30 is connected to each bridge branch 11 and the current sampling circuit 20, respectively, to control the upper bridge 111 and lower bridge 112 of the three bridge branches 11 to conduct alternately according to the phase current on each phase line, thereby driving the motor M to rotate.

[0052] For example, the controller 30 can be an FOC controller 30 integrating an FOC control algorithm. When the controller 30 receives the phase currents on the three phase lines AOUT, BOUT, and COUT of the motor M collected by the current sampling circuit 20, the controller 30 generates corresponding control signals based on the three phase currents and sends the control signals to the three bridge branches 11 of the three-phase inverter bridge 10 to control the upper bridge 111 and lower bridge 112 of the three bridge branches 11 to conduct alternately, thereby driving the motor M to rotate. It should be noted that the controller 30 generating corresponding control signals based on the phase currents on the three phase lines AOUT, BOUT, and COUT of the motor M collected by the current sampling circuit 20 is a conventional technical means in this field, and will not be described in detail in this embodiment.

[0053] In this embodiment, since the three first sampling resistors Rs1 are connected one-to-one between the connection point of the upper bridge 111 and the lower bridge 112 of the three bridge branches 11 and the three phase lines AOUT, BOUT, and COUT of the motor M, when current flows through each phase line of the motor M, current also flows through the first sampling resistor Rs1 connected to the corresponding phase line. This makes the waveform change of the voltage difference formed across each first sampling resistor Rs1 the same as the waveform change of the current flowing through the corresponding phase line, for example, both are sinusoidal waves, thereby realizing the detection of phase current. This structure allows the detection of phase current to be independent of the conduction time of the upper bridge 111 and lower bridge 112 of each bridge branch 11 in the three-phase inverter bridge 10. This is beneficial for accurately acquiring phase current in high-speed control scenarios. In turn, it can ensure that the controller 30 controls the upper bridge 111 and lower bridge 112 of the three bridge branches 11 to conduct alternately according to the phase current on each phase line, so as to drive the motor M to rotate at high speed. This is beneficial for the controller 30 to perform effective FOC control on the motor M, so that the motor drive device 100 can meet the high-speed control requirements of the motor M.

[0054] It should be noted that in another related technology, the phase current detection method of motor M is as follows: two first sampling resistors Rs1 are used to collect the phase current on two phase lines of motor M, and the third phase current is calculated using these two phase currents. Compared with this detection method, this application sets three first sampling resistors Rs1 one-to-one between the connection point of the upper bridge 111 and the lower bridge 112 of the three bridge branches 11 and the three phase lines AOUT, BOUT, and COUT of motor M. By using the three first sampling resistors Rs1 to collect the phase current on the three phase lines AOUT, BOUT, and COUT of motor M one-to-one, the accuracy of phase current detection can be ensured, and the error caused by calculating the third phase current can be avoided. Furthermore, this method of directly collecting the three phase currents places lower demands on the computing performance of controller 30, which helps to reduce the cost of controller 30.

[0055] In one implementation, please refer to the following: Figure 2 and Figure 3 The current sampling circuit 20 also includes a second sampling resistor Rs2, which is connected between the common terminal of the lower bridge 112 of the three bridge branches 11 and ground to collect the total current on the three phase lines AOUT, BOUT, and COUT. The second sampling resistor Rs2 is connected to the controller 30 to provide the total current to the controller 30, so that when the total current is greater than a preset current threshold, the controller 30 controls both the upper bridge 111 and the lower bridge 112 of the three bridge branches 11 to be turned off.

[0056] The second sampling resistor Rs2 can provide the total current to the controller 30 in the following way: the second sampling resistor Rs2 provides the voltage difference across its terminals to the controller 30. Since the waveform of the voltage difference across the second sampling resistor Rs2 is the same as the waveform of the total current on the three phase lines AOUT, BOUT, and COUT of the motor M, the total current can be provided to the controller 30 by providing the voltage difference corresponding to the total current.

[0057] In practical applications, when the total current on the three phase lines AOUT, BOUT, and COUT of motor M is too high, it will not only cause motor M to overheat and approach shutdown, but also cause excessive power from motor M, which may easily damage the on-board equipment driven by motor M. Therefore, in this embodiment, by setting a second sampling resistor Rs2 between the common terminal of the lower bridge 112 of the three bridge branches 11 and ground, the total current on the three phase lines of motor M is collected by the second sampling resistor Rs2 and transmitted to the controller 30. This allows the controller 30 to control the upper bridge 111 and lower bridge 112 of the three bridge branches 11 to be cut off when the total current exceeds a preset current threshold. In this way, when the total current on the three phase lines of motor M is too high, the three-phase inverter bridge 10 can be controlled to stop outputting three-phase AC voltage to motor M, thereby controlling motor M to stop running, providing overheat protection for motor M, and protecting the on-board equipment during the driving process.

[0058] In one implementation, please refer to the following: Figure 2 and Figure 3 In each bridge branch 11, the upper bridge 111 includes a first transistor Q1, and the lower bridge 112 includes a second transistor Q2. The first terminal of the first transistor Q1 is connected to the first power supply voltage VCC1, the second terminal of the first transistor Q1 is connected to the first terminal of the second transistor Q2, the second terminal of the second transistor Q2 is grounded, the control terminal of the first transistor Q1 is connected to the controller 30 through the first resistor R1, and the control terminal of the second transistor Q2 is connected to the controller 30 through the second resistor R2.

[0059] For example, the controller 30 controls the upper bridge 111 to turn on and off in the following way: Taking the first transistor Q1 as an NMOS transistor, the first terminal of the first transistor Q1 is its drain, the second terminal of the first transistor Q1 is its source, and the control terminal of the first transistor Q1 is its gate. When the controller 30 provides a high level to the gate of the first transistor Q1 through the first resistor R1, the first transistor Q1 is turned on; when the controller 30 provides a low level to the gate of the first transistor Q1 through the first resistor R1, the first transistor Q1 is turned off. By connecting the first resistor R1 between the controller 30 and the gate of the first transistor Q1, the first resistor R1 and the junction capacitance inside the first transistor Q1 form an RC circuit. This structure allows the gate voltage of the first transistor Q1 to rise smoothly when a high level is applied to the gate, adjusting the waveform of the gate voltage of the first transistor Q1 and preventing oscillation, thereby providing EMC protection. Similarly, the way controller 30 controls the lower bridge 112 to turn on and off can be referred to the way controller 30 controls the upper bridge 111 to turn on and off, and will not be repeated here.

[0060] Furthermore, Bridge Branch Road 11 includes at least one of the following:

[0061] The upper bridge 111 includes a first series branch L1, which includes a third resistor R3 and a first Zener diode ZD1 connected in series. The first series branch L1 is connected in parallel with the first resistor R1.

[0062] The upper bridge 111 includes a second series branch L2, which includes a fourth resistor R4 and a first capacitor C1 connected in series. The second series branch L2 is connected between the first terminal and the second terminal of the first transistor Q1.

[0063] The lower bridge 112 includes a third series branch L3, which includes a fifth resistor R5 and a second Zener diode ZD2 connected in series. The third series branch L3 is connected in parallel with the second resistor R2.

[0064] The lower bridge 112 includes a fourth series branch L4, which includes a sixth resistor R6 and a second capacitor C2 connected in series. The fourth series branch L4 is connected between the first and second terminals of the second transistor Q2.

[0065] In this embodiment, by connecting the first series branch L1 in parallel with the first resistor R1, when the controller 30 provides a low level to the gate of the first transistor Q1, the electrical energy at the gate of the first transistor Q1 can be released through the third resistor R3 and the first Zener diode ZD1 in the first series branch L1, achieving the purpose of rapid discharge. This is beneficial for quickly controlling the conduction and cutoff of the first transistor Q1, shortening its heat dissipation time, and extending the service life of the first transistor Q1.

[0066] Furthermore, by connecting the second series branch L2 between the first and second terminals of the first transistor Q1, the RC circuit formed by the fourth resistor R4 and the first capacitor C1 in the second series branch L2 can act as a buffer when the first and second terminals of the first transistor Q1 are turned on, thus avoiding the generation of oscillation waveforms due to the sudden turn-on of the first and second terminals of the first transistor Q1, thereby reducing the external radiated energy and improving the EMC protection effect.

[0067] It should be noted that the working principle and function of the third series branch L3 can be referred to the working principle and function of the first series branch L1, and the working principle and function of the fourth series branch L4 can be referred to the working principle and function of the second series branch L2, which will not be elaborated here.

[0068] In one implementation, please refer to the following: Figures 2 to 4 The current sampling circuit 20 also includes three current sensing amplifier circuits 21 and a voltage follower circuit 22. The first input terminal of each current sensing amplifier circuit 21 is connected to the first terminal of each first sampling resistor Rs1, the second input terminal of each current sensing amplifier circuit 21 is connected to the second terminal of each first sampling resistor Rs1, and the output terminal of each current sensing amplifier circuit 21 is connected to the controller 30 to provide the controller 30 with the voltage difference across the corresponding first sampling resistor Rs1, so that the controller 30 determines the corresponding phase current based on the voltage difference. The input terminal of the voltage follower circuit 42 is connected to the second power supply voltage VCC2, and the output terminal of the voltage follower circuit 22 is connected to the reference voltage terminal of each of the three current sensing amplifier circuits 21 to provide a reference voltage to each current sensing amplifier circuit 21.

[0069] For example, three first sampling resistors Rs1 respectively collect the phase currents on the first phase line AOUT, the second phase line BOUT, and the third phase line COUT. Three current sensing amplifier circuits 21 include a first current sensing amplifier circuit 21A, a second current sensing amplifier circuit, and a third current sensing amplifier circuit. The first input terminal PA_P and the second input terminal PA_N of the first current sensing amplifier circuit 21A are respectively connected to the first and second terminals of the first sampling resistor Rs1 connected to the first phase line AOUT. The first and second input terminals of the second current sensing amplifier circuit are respectively connected to the first and second terminals of the first sampling resistor Rs1 connected to the second phase line BOUT. The first and second input terminals of the third current sensing amplifier circuit are respectively connected to the first and second terminals of the first sampling resistor Rs1 connected to the third phase line COUT. The output terminals of the first, second, and third current sensing amplifier circuits are all connected to the controller 30. Thus, the first current sensing amplifier circuit 21A, the second current sensing amplifier circuit, and the third current sensing amplifier circuit can transmit the voltage difference corresponding to the phase current on the first phase line AOUT, the second phase line BOUT, and the third phase line COUT to the controller 30, so that the controller 30 can determine the corresponding phase current based on the voltage difference and use the determined phase current for FOC control.

[0070] Each current-sensing amplifier circuit 21 includes a first voltage divider circuit 211, a second voltage divider circuit 212, and a difference circuit 213. Taking the first current-sensing amplifier circuit 21A as an example, the input terminal of the first voltage divider circuit 211 constitutes the first input terminal PA_P of the first current-sensing amplifier circuit 21A, and the input terminal of the second voltage divider circuit 212 constitutes the second input terminal PA_N of the first current-sensing amplifier circuit 21A. The output terminal of the first voltage divider circuit 211 is connected to the first input terminal of the difference circuit 213, and the output terminal of the second voltage divider circuit 212 is connected to the second input terminal of the difference circuit 213. The output terminal of the difference circuit 213 constitutes the output terminal of the current-sensing amplifier circuit 21. After obtaining the voltages of the first and second terminals of the first sampling resistor Rs1 through the first voltage divider circuit 211 and the second voltage divider circuit 212 in a one-to-one correspondence, the difference circuit 213 performs a difference operation on the voltages of the first and second terminals of the first sampling resistor Rs1, amplifies them, and transmits them to the controller 30.

[0071] More specifically, the first voltage divider circuit 211 includes a first resistor R1 and a second resistor R2. The first end of the first resistor R1 forms the input terminal of the first voltage divider circuit 211. The second end of the first resistor R1 is connected to the first end of the second resistor R2. The second end of the second resistor R2 is grounded. The connection point between the second ends of the first resistor R1 and the first ends of the second resistor R2 forms the output terminal of the first voltage divider circuit 211. The second voltage divider circuit 212 includes a third resistor R3 and a fourth resistor R4. The first end of the third resistor R3 forms the input terminal of the first voltage divider circuit 211. The second end of the third resistor R3 is connected to the first end of the fourth resistor R4. The second end of the fourth resistor R4 is grounded. The connection point between the second ends of the third resistor R3 and the first ends of the fourth resistor R4 forms the output terminal of the first voltage divider circuit 211. The resistance values ​​of the first resistor R1 and the third resistor R3 are equal, and the resistance values ​​of the second resistor R2 and the fourth resistor R4 are equal.

[0072] The difference circuit 213 includes a first operational amplifier OP1, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and an eighth resistor R8. The first terminal of the fifth resistor R5 forms the first input terminal of the difference circuit 213. The second terminal of the fifth resistor R5 is connected to the non-inverting input terminal IN1+ of the first operational amplifier OP1 and to the first terminal of the sixth resistor R6, which receives the reference voltage V_REF. The first terminal of the seventh resistor R7 forms the second input terminal of the difference circuit 213. The second terminal of the seventh resistor R7 is connected to the inverting input terminal IN1- of the first operational amplifier OP1 and is connected to the output terminal OUT1 of the first operational amplifier OP1 via the eighth resistor R8. The resistance values ​​of the fifth resistor R5 and the seventh resistor R7 are equal, and the resistance values ​​of the sixth resistor R6 and the eighth resistor R8 are equal. This allows the difference circuit 213 to calculate the difference between the voltages at the first and second terminals of the first sampling resistor Rs1 before proportionally amplifying or attenuating the voltage.

[0073] Preferably, the difference circuit 213 further includes a first capacitor C1, a second capacitor C2, a ninth resistor R9, and a Zener diode ZD. The non-inverting input terminal IN1+ of the first operational amplifier OP1 is grounded through the first capacitor C1. The output terminal OUT1 of the first operational amplifier OP1 is connected to the first end of the ninth resistor R9. The second end of the ninth resistor R9 is grounded through the second capacitor C2 and the Zener diode ZD.

[0074] For example, the voltage follower circuit 22 includes a second operational amplifier OP2. The non-inverting input terminal IN2+ of the second operational amplifier OP2 constitutes the input terminal of the voltage follower circuit 22, and the inverting input terminal IN2- of the second operational amplifier OP2 is connected to its output terminal OUT2. The output terminal OUT2 of the second operational amplifier OP2 constitutes the output terminal of the voltage follower circuit 22. The voltage follower circuit 22 can be connected to the second power supply voltage VCC2 through a third voltage divider circuit. The third voltage divider circuit includes a tenth resistor R10 and an eleventh resistor R11. The first end of the tenth resistor R10 is connected to the second power supply voltage VCC2, and the second end of the tenth resistor R10 is connected to the first end of the eleventh resistor R11. The second end of the eleventh resistor R11 is grounded. The connection point of the tenth resistor R10 and the eleventh resistor R11 is connected to the input terminal of the voltage follower circuit 22. The output terminal of the voltage follower circuit 22 can provide a reference voltage externally through a twelfth resistor R12.

[0075] It should be noted that in related technologies, the detection of phase current is limited by the conduction time of the lower bridge 112 in the three-phase inverter circuit. This means that when the conduction time of the lower bridge 112 is very short, the voltage difference across the sampling resistor Rs needs to be amplified by the operational amplifier within a very short time. This increases the slew rate requirement of the operational amplifier and easily increases its cost. In this application, since the detection of phase current is no longer limited by the conduction time of the upper bridge 111 and lower bridge 112 of each bridge branch 11 in the three-phase inverter bridge 10, the voltage difference across the first sampling resistor Rs1 can be amplified by the current sensing amplifier circuit 21 for a longer time. This reduces the slew rate requirement of the first operational amplifier OP1 in the current sensing amplifier circuit 21, and is more conducive to reducing the cost of the first operational amplifier OP1. Furthermore, since the first operational amplifier OP1 is powered by a single power supply, and the voltage difference sampled across the first sampling resistor Rs1 can be either positive or negative, the voltage difference can be boosted by using the voltage follower circuit 22 to provide a reference voltage V_REF to the first operational amplifier OP1 of each current sensing amplifier circuit 21. This ensures that the voltage difference is positive, so that the current sensing amplifier circuit 21 can correctly amplify or attenuate the voltage difference before transmitting it to the controller 30, which is beneficial to improving the effectiveness of FOC control.

[0076] Preferably, the first operational amplifier OP1 and the second operational amplifier OP2 can be integrated into the same chip. Furthermore, the specific structure and operating principle of the second current-sensing amplifier circuit and the third current-sensing amplifier circuit can be found in the first current-sensing amplifier circuit 21A, and will not be elaborated here.

[0077] In one implementation, please refer to the following: Figure 2 , Figure 3 and Figure 5The current sampling circuit 20 also includes three first magnetic beads FB1, which are connected one-to-one between the three first sampling resistors Rs1 and the three phase lines AOUT, BOUT, and COUT. The first terminal of each first magnetic bead FB1 is grounded through a third capacitor C3, and the second terminal of each first magnetic bead FB1 is grounded through a first varistor RV1. By connecting the three first magnetic beads FB1 one-to-one between the three first sampling resistors Rs1 and the three phase lines AOUT, BOUT, and COUT, noise and spike interference during signal transmission can be suppressed, which is beneficial to improving the EMC performance of the current sampling circuit 20. Furthermore, by grounding the first terminal of the first magnetic bead FB1 through the third capacitor C3, the third capacitor C3 can also buffer the voltage at the connection point between the first sampling resistor Rs1 and the corresponding phase line, which also helps to improve the EMC performance of the current sampling circuit 20. Furthermore, by grounding the second end of the first magnetic bead FB1 using the first varistor RV1, when the motor M is connected to the three phase lines AOUT, BOUT, and COUT through the interface CN1, the first varistor RV1 can play a role in protecting against static electricity, thereby providing static electricity protection for the current sampling circuit 20 and the rest of the circuits of the motor drive device 100.

[0078] In one implementation, please refer to the following: Figure 2 , Figure 3 and Figure 6 The motor drive unit 100 further includes at least one of the following:

[0079] The bridge drive circuit 40 is connected between the controller 30 and the three-phase inverter bridge 10. It is used to amplify the control signal and transmit it to the three-phase inverter bridge 10. The control signal is used to alternately turn on the upper bridge 111 and the lower bridge 112 of the three bridge branches 11 in the three-phase inverter bridge 10.

[0080] The Hall signal detection circuit 50 is used to detect and transmit the rotation angle of the three-phase winding to the controller 30 so that the controller 30 controls the rotation angle of the motor M according to the rotation angle of the three-phase winding.

[0081] The bridge drive circuit 40 can be implemented using the driver chip of the three-phase inverter bridge 10. The configuration circuit of the driver chip can be set with reference to its chip manual. This application embodiment does not limit the driver chip of the three-phase inverter bridge 10. In practical applications, since the level of the control signal output by the controller 30 is low, the control signal cannot directly drive the three-phase inverter bridge 10. Therefore, in this embodiment, by setting the bridge drive circuit 40 between the controller 30 and the three-phase inverter bridge 10, the control signal can be amplified by the bridge drive circuit 40 and transmitted to the three-phase inverter bridge 10 to drive the three-phase inverter bridge 10.

[0082] like Figure 6 As shown, the Hall signal detection circuit 50 includes three Hall sensors (not shown in the figure), a first resistor R1, a second resistor R2, and a first capacitor C1. Each Hall sensor is located inside the motor M and is used to detect the rotation angle of each phase winding of the motor M. The first end of the first resistor R1 is connected to the second power supply voltage VCC2. The second end of the first resistor R1 is connected to the first end of the second resistor R2, and the second end of the second resistor R2 is grounded through the first capacitor C1. The connection point of the first resistor R1 and the second resistor R2 is connected to a Hall sensor, and the second end of the second resistor R2 is connected to the controller 30. The rotation angle detected by each Hall sensor, such as HALL_A, is transmitted to the controller 30 through the voltage divider circuit formed by the first resistor R1 and the second resistor R2. The controller 30 controls the rotation angle of the motor M according to the rotation angle of the three-phase winding, which is beneficial to realize the closed-loop control of the FOC algorithm.

[0083] In addition, such as Figure 5 As shown, the Hall signal detection circuit 50 also includes three third magnetic beads FB3. The first terminals of the three third magnetic beads FB3 are connected one-to-one with the three Hall sensors, so that the rotation angles HALL_A, HALL_B, and HALL_C detected by the three Hall sensors are output after noise is eliminated by the third magnetic beads FB3. The first terminal of each third magnetic bead FB is also grounded through the second varistor RV2 to protect against static electricity.

[0084] In one implementation, please refer to Figure 1 , Figure 7 and Figure 9 The motor drive unit 100 also includes a bridge drive circuit 40 and a power module 60. The power module 60 includes a power supply circuit 61, a step-down circuit 62, a current limiting circuit 63, and a step-up / step-down circuit 64. The power supply circuit 61 is used to convert the battery power BAT into a fourth power supply voltage VCC4.

[0085] The step-down circuit 62 is used to step down the fourth power supply voltage VCC4 to the third power supply voltage VCC3 to supply power to the controller 30 and the motor M. The third power supply voltage VCC3 is lower than the fourth power supply voltage VCC4. The step-down circuit 62 can be a low-dropout regulator (LDO). The fourth power supply voltage VCC4 can be 12V, and the third power supply voltage VCC3 can be 5V.

[0086] The current limiting circuit 63 is connected between the third power supply voltage VCC3 and the motor M.

[0087] The buck-boost circuit 64 is used to boost or buck the fourth power supply voltage VCC4 to the fifth power supply voltage VCC5 to power the current sampling circuit 20 and the bridge drive circuit 40. The buck-boost circuit 64 can be a Buck-Boost circuit; for example, it can boost or buck the fourth power supply voltage VCC4, which floats between 9V and 15V, to a stable 12V fifth power supply voltage VCC5.

[0088] Based on this, the battery power supply BAT can be converted into a third power supply voltage VCC3 to power the controller 30 and the motor M, and the battery power supply BAT can be converted into a fifth power supply voltage VCC5 to power the current sampling circuit 20 and the bridge drive circuit 40, thereby realizing the power supply of each module in the motor drive device 100.

[0089] In one implementation, please refer to the following: Figure 7 and Figure 8 The current limiting circuit 63 includes a third transistor Q3, a first transistor B1, and a second transistor B2.

[0090] The source of the third transistor Q3 is connected to the first terminal of the seventh resistor R7, the drain of the third transistor Q3 is connected to the power supply terminal of the motor M, and the second terminal of the seventh resistor R7 is used to connect to the third power supply voltage VCC3.

[0091] The collector of the first transistor B1 is connected to the first end of the eighth resistor R8. The second end of the eighth resistor R8 is connected to the gate of the third transistor Q3. A ninth resistor R9 and a fourth capacitor C4 are connected in parallel between the second end of the eighth resistor R8 and the second end of the seventh resistor R7. The emitter of the first transistor B1 is grounded. A tenth resistor R10 is connected between the base and emitter of the first transistor B1. The base of the first transistor B1 is connected to the controller 30 through the eleventh resistor R11.

[0092] The collector of the second transistor B2 is connected to the gate of the third transistor Q3, the emitter of the second transistor B2 is connected to the second end of the seventh resistor R7, and the base of the second transistor B2 is connected to the first end of the seventh resistor R7 through the twelfth resistor R12.

[0093] Taking the first transistor Q1 as an NMOS transistor, the first transistor B1 as an NPN transistor, and the second transistor B2 as a PNP transistor as an example, the operation of the current limiting circuit 63 includes: when the controller 30 provides a high level to the base of the first transistor B1 through the eleventh resistor R11, both the emitter junction and collector junction of the first transistor B1 are in a forward bias state, and the first transistor B1 is saturated and turned on. The voltage divider circuit formed by the ninth resistor R9 and the eighth resistor R8 can make the gate-source voltage of the first transistor Q1 greater than the turn-on voltage, thereby controlling the first transistor Q1 to turn on, so that the third power supply voltage VCC3 supplies power to the power supply terminal of the motor M through the seventh resistor R7 and the first transistor Q1 in sequence, and provides the external power supply voltage V to the power supply terminal of the motor M. CC_M; During power supply, if the current flowing through the first transistor Q1 is too large, the voltage drop across the seventh resistor R7 will also increase. When the voltage between the collector and emitter of the second transistor B2 is greater than the turn-on voltage, the second transistor B2 will saturate and conduct, causing the gate-source voltage of the first transistor Q1 to decrease. Consequently, when the gate-source voltage of the first transistor Q1 is lower than the turn-on voltage, the first transistor Q1 will turn off, thus providing current limiting protection. When the controller 30 provides a low level to the base of the first transistor B1 through the eleventh resistor R11, both the emitter junction and collector junction of the first transistor B1 are reverse biased, the first transistor B1 will turn off, the second transistor Q2 will turn off, and the third power supply voltage VCC3 will stop supplying power to the motor M.

[0094] Based on this, by setting a current limiting circuit 63 between the third power supply voltage VCC3 and the motor M, the power supply module 60 can be protected against current limiting during the process of the controller 30 controlling the third power supply voltage VCC3 to supply power to the motor M, thus preventing the power supply module 60 from being burned out.

[0095] In one implementation, such as Figure 8 As shown, the current limiting circuit 63 further includes at least one of the following:

[0096] The thirteenth resistor R13 has its first terminal connected to the drain of the third transistor Q3, and its second terminal grounded.

[0097] The π-type filter circuit 631 is connected between the third power supply voltage VCC3 and the second terminal of the seventh resistor R7.

[0098] The π-type filter circuit 631 includes a fifth capacitor C5, a sixth capacitor C6, and a second ferrite bead FB2. The second ferrite bead FB2 is connected between the third power supply voltage VCC3 and the second terminal of the seventh resistor R7. The first terminal of the second ferrite bead FB2 is grounded through the fifth capacitor C5, and the second terminal of the second ferrite bead FB2 is grounded through the sixth capacitor C6.

[0099] In the above scheme, the drain of the third transistor Q3 is grounded through the thirteenth resistor R13. This allows the residual charge on the first transistor Q1 to be quickly discharged when the first transistor Q1 is turned off. Furthermore, by setting a π-type filter circuit 631 between the third power supply voltage VCC3 and the second terminal of the seventh resistor R7, interference on the third power supply voltage VCC3 can be filtered out, which is beneficial for providing stable power to the motor M.

[0100] In addition, the π-type filter circuit 631 can also provide a second power supply voltage VCC2 externally through the fourteenth resistor R14.

[0101] In one implementation, such as Figure 9 As shown, the power supply circuit 61 is connected to the battery power supply BAT via a connector interface (not shown in the attached figure). The power supply circuit 61 includes:

[0102] The interface protection sub-circuit 611, isolation sub-circuit 612, reverse connection protection sub-circuit 613, and filter sub-circuit 614 are connected in sequence; wherein, the input terminal of the interface protection sub-circuit 611 is used to connect to the battery power supply BAT, and the output terminal of the filter sub-circuit 614 is used to provide the fourth power supply voltage VCC4.

[0103] The interface protection sub-circuit 611 includes a TVS (Transient Voltage Suppressor) diode D1, a first capacitor C1, and a second capacitor C2. The first terminal of the TVS diode D1 forms the input terminal of the interface protection sub-circuit 611, and the second terminal of the TVS diode D1 is grounded. The series branch formed by the first capacitor C1 and the second capacitor C2 is connected in parallel with the TVS diode D1. This structure can suppress high voltage pulses generated on the battery power supply and protect the subsequent circuits.

[0104] The isolation sub-circuit 612 can be a common-mode inductor CMC1. By setting the isolation sub-circuit 612 between the interface protection sub-circuit 611 and the reverse connection protection sub-circuit 613, the connector of the battery power supply BAT can be isolated from the subsequent circuit of the power supply circuit 61. In addition, by setting the isolation sub-circuit 612 as a common-mode inductor CMC1, the common-mode inductor CMC1 can be used to allow differential-mode current to flow and suppress common-mode current to flow, thereby playing a role in EMC protection.

[0105] The reverse connection protection circuit 613 includes a PMOS transistor Q4, a first resistor R1, and a second resistor R2. The drain of the PMOS transistor Q4 is connected to the first output terminal of the isolation circuit 612, and the source of the PMOS transistor Q4 is connected to the first terminal of the first resistor R1. The second terminal of the first resistor R1 is grounded through the second resistor R2, and the gate of the PMOS transistor Q4 is connected to the junction of the first resistor R1 and the second resistor R2. When the battery power supply BAT is reverse-connected, the voltage applied to the gate of the PMOS transistor Q4 through the voltage divider circuit formed by the first resistor R1 and the second resistor R2 is at a high level, and the PMOS transistor Q4 is turned off, preventing the reverse-connected battery power supply BAT from continuing to supply power to the subsequent circuits, thus protecting the subsequent circuits. In addition, a Zener diode D2 is connected in parallel with the first resistor R1, and a third capacitor C3 is connected in parallel with the second resistor R2, which can play a role in voltage regulation and buffering when the battery power supply BAT is connected in the correct direction.

[0106] The filter sub-circuit 614 includes capacitors C4 through C14, a first inductor L1, a first electrolytic capacitor EC1, and a second electrolytic capacitor EC2. The series branches formed by capacitors C4 and C5, C6 and C7, and C8 and C9 are connected between the first terminal of the first resistor R1 and the second terminal of the second resistor R2. Capacitors C10 through C14, EC1, and EC2 are all connected between the first terminal of the first resistor R1 and the second terminal of the second resistor R2. The first inductor L1 is connected between the first terminal of the eighth capacitor C8 and the first terminal of the tenth capacitor C10. This structure allows the filter sub-circuit 614 to form a CLC filter circuit. Thus, interference signals can be filtered out during power supply.

[0107] The application also provides an in-vehicle device, including a motor M and a motor drive device 100 according to any of the above embodiments. The motor drive device 100 is connected to the motor M to drive the motor M to rotate. Since this in-vehicle device adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here. Among them, the in-vehicle device includes, but is not limited to, flip-up instruments, sliding screens, ceiling-mounted screens, and other in-vehicle devices that can be flipped.

[0108] Furthermore, in this application, unless otherwise expressly specified and limited, the terms "connected," "linked," "stacked," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0109] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications or equivalent substitutions made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A motor drive device, characterized in that, include: The three-phase inverter bridge has three bridge branches, and the connection points of the upper and lower bridges of the three bridge branches are connected one-to-one with the three phase lines of the motor. The current sampling circuit has three first sampling resistors, each of which is connected between the connection point of the upper and lower bridges of each bridge branch and each phase line, so as to collect the phase current on the corresponding phase line. The controller is connected to each of the bridge branches and the current sampling circuit respectively, so as to control the upper and lower bridges of the three bridge branches to alternately conduct according to the phase current on each phase line, so as to drive the motor to rotate at high speed.

2. The motor drive device according to claim 1, characterized in that, The current sampling circuit also includes: The second sampling resistor is connected between the common terminal of the lower bridge of the three bridge branches and ground to collect the total current on the three phase lines; The second sampling resistor is connected to the controller to provide the total current to the controller, so that when the total current is greater than a preset current threshold, the controller controls the upper and lower bridges of the three bridge branches to be cut off.

3. The motor drive device according to claim 1, characterized in that, In each of the bridge branches, the upper bridge includes a first transistor, and the lower bridge includes a second transistor. A first terminal of the first transistor is connected to a first power supply voltage, and a second terminal of the first transistor is connected to the first terminal of the second transistor. The second terminal of the second transistor is grounded. The control terminal of the first transistor is connected to the controller through a first resistor, and the control terminal of the second transistor is connected to the controller through a second resistor. Each bridge branch includes at least one of the following: The upper bridge includes a first series branch, which includes a third resistor and a first Zener diode connected in series, and the first series branch is connected in parallel with the first resistor; The upper bridge includes a second series branch, which includes a fourth resistor and a first capacitor connected in series, and the second series branch is connected between the first terminal and the second terminal of the first transistor. The lower bridge includes a third series branch, which includes a fifth resistor and a second Zener diode connected in series, and the third series branch is connected in parallel with the second resistor; The lower bridge includes a fourth series branch, which includes a sixth resistor and a second capacitor connected in series. The fourth series branch is connected between the first and second terminals of the second transistor.

4. The motor drive device according to claim 1, characterized in that, The current sampling circuit further includes three current-sensing amplifier circuits and a voltage follower circuit. The first input terminal of each current-sensing amplifier circuit is connected to the first terminal of each first sampling resistor, and the second input terminal of each current-sensing amplifier circuit is connected to the second terminal of each first sampling resistor. The output terminal of each current-sensing amplifier circuit is connected to the controller to provide the controller with the voltage difference across the corresponding first sampling resistor, so that the controller determines the corresponding phase current based on the voltage difference. The input terminal of the voltage follower circuit is connected to the second power supply voltage, and the output terminal of the voltage follower circuit is connected to the reference voltage terminal of each of the three current-sensing amplifier circuits to provide a reference voltage to each current-sensing amplifier circuit. And / or, the current sampling circuit further includes three magnetic beads, which are connected one-to-one between the three first sampling resistors and the three phase lines; wherein, the first end of each magnetic bead is grounded through a third capacitor, and the second end of each magnetic bead is grounded through a varistor.

5. The motor drive device according to claim 1, characterized in that, It also includes at least one of the following: A bridge drive circuit, connected between the controller and the three-phase inverter bridge, is used to amplify the control signal and transmit it to the three-phase inverter bridge; the control signal is used to alternately turn on the upper and lower bridges of the three bridge branches in the three-phase inverter bridge; A Hall effect signal detection circuit is used to detect and transmit the rotation angle of the three-phase windings to the controller, so that the controller controls the rotation angle of the motor according to the rotation angle of the three-phase windings.

6. The motor drive device according to claim 1, characterized in that, The motor drive device further includes a bridge drive circuit and a power supply module, the power supply module comprising: Power supply circuit, used to convert battery power to a fourth power supply voltage; A step-down circuit is used to step down the fourth power supply voltage to a third power supply voltage to supply power to the controller and the motor, wherein the third power supply voltage is lower than the fourth power supply voltage; A current limiting circuit is connected between the third power supply voltage and the motor; A step-up / step-down circuit is used to boost or step down the fourth power supply voltage to a fifth power supply voltage to supply power to the current sampling circuit and the bridge drive circuit.

7. The motor drive device according to claim 6, characterized in that, The current limiting circuit includes: The third transistor has its source connected to the first terminal of the seventh resistor and its drain connected to the power supply terminal of the motor. The second terminal of the seventh resistor is used to connect to the third power supply voltage. The first transistor has its collector connected to the first end of the eighth resistor, the second end of the eighth resistor connected to the gate of the third transistor, and a ninth resistor and a fourth capacitor connected in parallel between the second end of the eighth resistor and the second end of the seventh resistor. The emitter of the first transistor is grounded, and a ninth resistor is connected between the base of the first transistor and the emitter. The base of the first transistor is connected to the controller through a tenth resistor. The collector of the second transistor is connected to the gate of the third transistor, the emitter of the second transistor is connected to the second end of the seventh resistor, and the base of the second transistor is connected to the first end of the seventh resistor through the twelfth resistor.

8. The motor drive device according to claim 7, characterized in that, The current limiting circuit further includes at least one of the following: The thirteenth resistor has its first end connected to the drain of the third transistor and its second end grounded. A π-type filter circuit is connected between the third power supply voltage and the second terminal of the seventh resistor.

9. The motor drive device according to claim 6, characterized in that, The power supply circuit is connected to the battery power source via a connector interface, and the power supply circuit includes: The interface protection sub-circuit, isolation sub-circuit, reverse connection protection sub-circuit, and filter sub-circuit are connected in sequence; wherein, the input terminal of the interface protection sub-circuit is used to connect to the battery power supply, and the output terminal of the filter sub-circuit is used to provide the fourth power supply voltage.

10. A vehicle-mounted device, characterized in that, The invention includes a motor and a motor drive device according to any one of claims 1 to 9, wherein the motor drive device is connected to the motor to drive the motor to rotate.

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