Motor control circuit and motor drive control method

Abstract

The application discloses a motor control circuit and a motor driving control method, and belongs to the technical field of brushless direct current motor driving control. The motor control circuit comprises a power supply voltage detection unit, a single-chip microcomputer, a three-phase half-bridge circuit unit and a half-bridge driving unit. The three-phase half-bridge circuit unit comprises a U-phase half-bridge circuit for outputting a U-phase voltage, a V-phase half-bridge circuit for outputting a V-phase voltage and a W-phase half-bridge circuit for outputting a W-phase voltage. The single-chip microcomputer continuously outputs an enable signal based on a received analog voltage signal or a control instruction signal. The half-bridge driving unit makes the upper bridge arm circuit closed and the lower bridge arm circuit opened during motor braking according to the enable signal, forms a short-circuit closed loop to the ground, and enables the motor to generate a reverse braking torque. In the premise of not needing to additionally increase the cost of a hardware circuit, the motor reverse rotation or continuous rotation in the normal shutdown and accidental power-off working conditions is prevented.

Description

Technical Field

[0001] This invention relates to a motor control circuit and a motor drive control method, belonging to the field of brushless DC motor drive control technology. Background Technology

[0002] Because Stirling refrigerators have a closed air pressure structure inside, a normal shutdown only shuts down the PWM output and directly turns off the drive chip enable, leaving the motor windings in an open-circuit, suspended state. This can lead to the rotor inertia superimposed with the internal air pressure doing work in the opposite direction. Currently, under controlled shutdown and power failure conditions, Stirling refrigerators exhibit motor continuation and reverse rotation, which can cause mechanical shock, structural wear, and back electromotive force breakdown of the drive chip.

[0003] To solve the above problems, existing solutions mostly involve adding pure hardware circuits, such as adding relays and thyristor braking circuits. This requires adding a large number of additional components, occupying PCB area and increasing hardware costs. Moreover, prematurely turning off the driver chip will cause braking failure, making it incompatible with both normal shutdown and unexpected power failure conditions, resulting in extremely poor applicability. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a motor control circuit and motor drive control method that can prevent the motor from reversing or continuing to rotate under normal shutdown and unexpected power failure conditions without increasing the cost of the hardware circuit. This solves the problems of high hardware cost and poor compatibility of current methods for preventing motor reversal in Stirling refrigerators.

[0005] To solve the above-mentioned technical problems, the present invention is implemented using the following technical solution: This invention provides a motor control circuit, comprising: The power supply voltage detection unit is used to detect the power supply voltage and output an analog voltage signal. A microcontroller, connected to the power supply voltage detection unit, is used to receive analog voltage signals or control command signals and output an enable signal. The three-phase half-bridge circuit unit includes a U-phase half-bridge circuit for outputting U-phase voltage, a V-phase half-bridge circuit for outputting V-phase voltage, and a W-phase half-bridge circuit for outputting W-phase voltage. Each phase half-bridge circuit is connected to the corresponding motor phase voltage input port; each phase half-bridge circuit includes a connected upper bridge arm circuit and a lower bridge arm circuit. The half-bridge drive unit is connected to the microcontroller and the three-phase half-bridge circuit unit. It is used to turn off the upper bridge arm circuit and turn on the lower bridge arm circuit according to the enable signal, forming a closed loop to ground, and the motor generates reverse braking torque.

[0006] Optionally, the microcontroller also outputs an action signal; The half-bridge drive unit includes a drive chip, a shielding circuit, and a sampling circuit; The sampling circuit is connected to the driver chip through the shielding circuit; The driver chip is connected to the upper bridge arm circuit and the lower bridge arm circuit; The sampling circuit is connected to the lower bridge arm circuit; The sampling circuit is used to sample the voltage of the lower bridge arm circuit and output the sampled voltage to the driver chip through the shielding circuit. The shielding circuit is used to switch the connection state between the sampling circuit and the driver chip according to the action signal.

[0007] Optionally, the driver chip is provided with an enable input port, a detection port, and six output ports; The enable input port is connected to the microcontroller and is used to receive the enable signal; The detection port is connected to the shielding circuit and is used to input the sampling voltage; The six output ports are respectively connected to the upper and lower bridge arm circuits of each phase half-bridge circuit.

[0008] Optionally, the shielding circuit includes a first shielding MOS transistor, a second shielding MOS transistor, a first shielding resistor, and a second shielding resistor; The source of the first shielded MOS transistor is connected to a power supply, the gate of the first shielded MOS transistor is connected to an action signal, and the drain of the first shielded MOS transistor is connected to one end of the first shielding resistor. The other end of the first shielding resistor is grounded; The gate of the second shielded MOS transistor is connected to the sampling circuit; the source of the second shielded MOS transistor is connected to the drain of the first shielded MOS transistor; and the drain of the second shielded MOS transistor is connected to one end of the second shielding resistor and the driving chip, respectively. The other end of the second shielding resistor is grounded.

[0009] Optionally, the sampling circuit includes a sampling capacitor, a first sampling resistor, a second sampling resistor, and a third sampling resistor; One end of the sampling capacitor is connected to one end of the first sampling resistor and one end of the third sampling resistor, respectively; The other end of the sampling capacitor is connected to the gate of the second shielded MOS transistor, the other end of the first sampling resistor, and one end of the second sampling resistor, respectively. The other end of the second sampling resistor and the other end of the third sampling resistor are both connected to the lower bridge arm circuit.

[0010] Optionally, the upper bridge arm circuit includes an upper bridge diode, a first upper bridge resistor, a second upper bridge resistor, a third upper bridge resistor, and an upper bridge MOSFET; The cathode of the upper bridge diode and one end of the second upper bridge resistor are both connected to the driving chip. The anode of the upper bridge diode is connected to one end of the first upper bridge resistor, and the other end of the first upper bridge resistor is connected to one end of the third upper bridge resistor. The source of the upper bridge MOSFET is connected to the power supply, the gate of the upper bridge MOSFET is connected to the other end of the second upper bridge resistor, and the drain of the upper bridge MOSFET is connected to the other end of the third upper bridge resistor. The lower bridge arm circuit includes a lower bridge diode, a first lower bridge resistor, a second lower bridge resistor, a third lower bridge resistor, and a lower bridge MOSFET; The cathode of the lower bridge diode and one end of the second lower bridge resistor are both connected to the driver chip. The anode of the lower bridge diode is connected to one end of the first lower bridge resistor, and the other end of the first lower bridge resistor is connected to one end of the third lower bridge resistor. The source of the lower bridge MOS transistor is connected to the drain of the upper bridge MOS transistor, the gate of the lower bridge MOS transistor is connected to the other end of the second lower bridge resistor, and the drain of the lower bridge MOS transistor is connected to the other end of the third lower bridge resistor.

[0011] In another aspect, the present invention provides a motor drive control method, based on the motor control circuit described above, the method comprising: Acquire analog voltage signals or control command signals; The motor operating state is determined based on the analog voltage signal or control command signal; wherein the motor operating state includes normal operating state and braking operating state; If the motor is in braking mode, it will continuously output enable and action signals.

[0012] Further, determining the motor operating state based on the analog voltage signal or control command signal includes: Determine the power supply voltage value based on the analog voltage signal; If the power supply voltage is lower than the preset voltage threshold, the motor will be in braking mode.

[0013] Furthermore, determining the motor operating state based on the analog voltage signal or control command signal further includes: If the control command signal is a stop command, the motor is in braking mode.

[0014] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: 1. This invention includes a power supply voltage detection unit, a microcontroller, a three-phase half-bridge circuit unit, and a half-bridge drive unit. The microcontroller continuously outputs an enable signal based on the received analog voltage signal or control command signal. The half-bridge drive unit closes the upper bridge arm circuit and opens the lower bridge arm circuit during motor braking according to the enable signal, forming a closed loop to ground. The motor can generate reverse braking torque. Without increasing the cost of additional hardware circuitry, it can prevent the motor from reversing or continuing to rotate under normal shutdown and unexpected power failure conditions. This solves the problems of high hardware cost and poor compatibility of current methods for preventing motor reversal in Stirling refrigerators.

[0015] 2. While retaining the sampling circuit's function of sampling high current, this invention enables the shielding circuit to switch the connection state between the sampling circuit and the drive chip during motor braking through an action signal. This temporarily shields the drive chip from detecting high current, avoiding the situation where the chip's protection locks up due to instantaneous braking high current. This ensures that the half-bridge drive unit can continuously generate reverse braking torque during motor braking. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall architecture of a motor control circuit provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the signal transmission direction between the microcontroller and the driver chip provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the circuit structure of the half-bridge driving unit provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the circuit structure of a three-phase half-bridge circuit unit provided in an embodiment of the present invention; Figure 5 This is a schematic flowchart of a motor drive control method provided in an embodiment of the present invention; Figure 6 This is a timing comparison diagram of the method proposed in the embodiments of the present invention and the traditional braking scheme; Figure 7 This is a timing diagram of a motor drive control method provided in an embodiment of the present invention. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention. Example 1

[0018] like Figure 1 and Figure 2 As shown, this embodiment provides a motor control circuit, including: a power supply voltage detection unit, a microcontroller, a three-phase half-bridge circuit unit, and a half-bridge drive unit; The power supply voltage detection unit is used to detect the power supply voltage and output an analog voltage signal. The microcontroller is connected to the power supply voltage detection unit to receive analog voltage signals or control command signals and output enable signals. The three-phase half-bridge circuit unit includes a U-phase half-bridge circuit for outputting U-phase voltage, a V-phase half-bridge circuit for outputting V-phase voltage, and a W-phase half-bridge circuit for outputting W-phase voltage; each phase half-bridge circuit is connected to the corresponding motor phase voltage input port; wherein, each phase half-bridge circuit includes a connected upper bridge arm circuit and a lower bridge arm circuit. The half-bridge drive unit is connected to the microcontroller and the three-phase half-bridge circuit unit. It is used to turn off the upper bridge arm circuit and turn on the lower bridge arm circuit according to the enable signal, forming a closed loop to ground, and the motor generates reverse braking torque. In this embodiment, the microcontroller also outputs an action signal; The half-bridge driver unit includes a driver chip, a shielding circuit, and a sampling circuit; The sampling circuit is connected to the driver chip through a shielding circuit; The driver chip is connected to the upper bridge arm circuit and the lower bridge arm circuit; The sampling circuit is connected to the lower bridge arm circuit; The sampling circuit is used to sample the voltage of the lower bridge arm circuit and outputs the sampled voltage to the driver chip through the shielding circuit. The shielding circuit is used to switch the connection state between the sampling circuit and the driver chip according to the action signal; Specifically: The driver chip has an enable input port, a detection port, and six output ports; In this embodiment, the driver chip is IR2136, the enable input port is the IR2136_EN pin, the detection port is the ITRIP pin, and the six output ports are the HO1, HO2 and HO3 pins of the upper bridge arm circuit, and the LO1, LO2 and LO3 pins of the lower bridge arm circuit, respectively. The microcontroller used is an STM32F103 series microcontroller. Its input pins include ADC_INT0 and GPIO_IN1, and its output pins include GPIO_OUT1 and GPIO_OUT2. ADC_INT0 is used to input analog power supply voltage signals, and GPIO_IN1 is used to input control command signals. GPIO_OUT1 is used to output enable signals, and GPIO_OUT2 is used to output action signals, which are overcurrent detection (CLD) disable signals. It should be noted that in this embodiment, the control command signal is a low-level signal; The enable input port is electrically connected to the GPIO_OUT1 pin; The input terminal of the shielding circuit is electrically connected to the GPIO_OUT2 pin, and the output terminal is electrically connected to the detection port.

[0019] like Figure 3 As shown, the shielding circuit includes a first shielding MOSFET Q11, a second shielding MOSFET Q12, a first shielding resistor R11, and a second shielding resistor R12; The source of the first shielded MOSFET Q11 is connected to the power supply VCC_3V3, the gate of the first shielded MOSFET Q11 serves as the input terminal of the shielding circuit and is connected to the action signal, and the drain of the first shielded MOSFET Q11 is electrically connected to one end of the first shielding resistor R11. The other end of the first shielding resistor R11 is grounded; The gate of the second shielded MOSFET Q12 is electrically connected to the output terminal of the sampling circuit; the source of the second shielded MOSFET Q12 is electrically connected to the drain of the first shielded MOSFET Q11; and the drain of the second shielded MOSFET Q12 is electrically connected to one end of the second shielding resistor R12 and the detection port of the driver chip, respectively. The other end of the second shielding resistor is grounded; The sampling circuit includes a sampling capacitor C0, a first sampling resistor R21, a second sampling resistor R22, and a third sampling resistor R23; One end of the sampling capacitor C0 is electrically connected to one end of the first sampling resistor R21 and one end of the third sampling resistor R23, respectively; The other end of the sampling capacitor C0 is used as the output terminal of the sampling circuit and is electrically connected to the gate of the second shielded MOS transistor Q12, the other end of the first sampling resistor R21, and one end of the second sampling resistor R22. The other end of the second sampling resistor R22 and the other end of the third sampling resistor R23 are electrically connected to the common terminal COM of the lower bridge arm circuit as the input terminals of the sampling circuit. When the gate of the first shielded MOSFET Q11 is connected to the action signal, the loop formed between the output of the sampling circuit, the gate of the second shielded MOSFET Q12, and the detection port is broken. The detection port temporarily loses its detection function, thereby temporarily shielding the driver chip from detecting large currents and avoiding the situation where the chip is locked up due to instantaneous braking large current.

[0020] Since each phase half-bridge circuit in this embodiment includes a connected upper bridge arm circuit and a lower bridge arm circuit, then: like Figure 4 As shown, the U-phase half-bridge circuit includes the U-phase upper bridge arm circuit and the U-phase lower bridge arm circuit; The U-phase upper bridge arm circuit includes a U-phase upper bridge diode D11, a first U-phase upper bridge resistor R31, a second U-phase upper bridge resistor R32, a third U-phase upper bridge resistor R33, and a U-phase upper bridge MOSFET Q21; The cathode of the U-phase upper bridge diode D11 and one end of the second U-phase upper bridge resistor R31 are both electrically connected to the HO1 pin of the driver chip. The anode of the U-phase upper bridge diode D11 is electrically connected to one end of the first U-phase upper bridge resistor R31, and the other end of the first U-phase upper bridge resistor R31 is electrically connected to one end of the third U-phase upper bridge resistor R33. The source of the U-phase upper bridge MOSFET Q21 is connected to the power supply VCC. The gate of the U-phase upper bridge MOSFET Q21 is electrically connected to the other end of the second U-phase upper bridge resistor R32. The drain of the U-phase upper bridge MOSFET Q21 is electrically connected to the other end of the third U-phase upper bridge resistor R33. The U-phase lower bridge arm circuit includes a U-phase lower bridge diode D12, a first U-phase lower bridge resistor R34, a second U-phase lower bridge resistor R35, a third U-phase lower bridge resistor R36, and a U-phase lower bridge MOSFET Q22. The cathode of the U-phase lower bridge diode D12 and one end of the second U-phase lower bridge resistor R34 are both electrically connected to the LO1 pin of the driver chip. The anode of the U-phase lower bridge diode D12 is electrically connected to one end of the first U-phase lower bridge resistor R34, and the other end of the first U-phase lower bridge resistor R34 is electrically connected to one end of the third U-phase lower bridge resistor R36. The source of the U-phase lower bridge MOSFET Q22 is electrically connected to the drain of the U-phase upper bridge MOSFET Q21. The gate of the U-phase lower bridge MOSFET Q22 is electrically connected to the other end of the second U-phase lower bridge resistor R35. The drain of the U-phase lower bridge MOSFET Q22 is electrically connected to the other end of the third U-phase lower bridge resistor R36, forming the common terminal COM of the lower bridge arm circuit.

[0021] The V-phase half-bridge circuit includes the V-phase upper bridge arm circuit and the V-phase lower bridge arm circuit; The V-phase upper bridge arm circuit includes a V-phase upper bridge diode D21, a first V-phase upper bridge resistor R41, a second V-phase upper bridge resistor R42, a third V-phase upper bridge resistor R43, and a V-phase upper bridge MOSFET Q31. The cathode of the V-phase upper bridge diode D21 and one end of the second V-phase upper bridge resistor R41 are both electrically connected to the HO2 pin of the driver chip. The anode of the V-phase upper bridge diode D21 is electrically connected to one end of the first V-phase upper bridge resistor R41, and the other end of the first V-phase upper bridge resistor R41 is electrically connected to one end of the third V-phase upper bridge resistor R43. The source of the V-phase upper bridge MOSFET Q31 is connected to the power supply VCC. The gate of the V-phase upper bridge MOSFET Q31 is electrically connected to the other end of the second V-phase upper bridge resistor R42. The drain of the V-phase upper bridge MOSFET Q31 is electrically connected to the other end of the third V-phase upper bridge resistor R43. The V-phase lower bridge arm circuit includes a V-phase lower bridge diode D22, a first V-phase lower bridge resistor R44, a second V-phase lower bridge resistor R45, a third V-phase lower bridge resistor R46, and a V-phase lower bridge MOSFET Q32. The cathode of the V-phase lower bridge diode D22 and one end of the second V-phase lower bridge resistor R44 are both electrically connected to the LO2 pin of the driver chip. The anode of the V-phase lower bridge diode D22 is electrically connected to one end of the first V-phase lower bridge resistor R44, and the other end of the first V-phase lower bridge resistor R44 is electrically connected to one end of the third V-phase lower bridge resistor R46. The source of the V-phase lower bridge MOSFET Q32 is electrically connected to the drain of the V-phase upper bridge MOSFET Q31. The gate of the V-phase lower bridge MOSFET Q32 is electrically connected to the other end of the second V-phase lower bridge resistor R45. The drain of the V-phase lower bridge MOSFET Q32 is electrically connected to the other end of the third V-phase lower bridge resistor R46, forming the common terminal COM of the lower bridge arm circuit.

[0022] The W-phase half-bridge circuit includes the W-phase upper bridge arm circuit and the W-phase lower bridge arm circuit; The W-phase upper bridge arm circuit includes a W-phase upper bridge diode D31, a first W-phase upper bridge resistor R51, a second W-phase upper bridge resistor R52, a third W-phase upper bridge resistor R53, and a W-phase upper bridge MOSFET Q41. The cathode of the W-phase upper bridge diode D31 and one end of the second W-phase upper bridge resistor R51 are both electrically connected to the HO3 pin of the driver chip. The anode of the W-phase upper bridge diode D31 is electrically connected to one end of the first W-phase upper bridge resistor R51, and the other end of the first W-phase upper bridge resistor R51 is electrically connected to one end of the third W-phase upper bridge resistor R53. The source of the W-phase upper bridge MOSFET Q41 is connected to the power supply VCC. The gate of the W-phase upper bridge MOSFET Q41 is electrically connected to the other end of the second W-phase upper bridge resistor R52. The drain of the W-phase upper bridge MOSFET Q41 is electrically connected to the other end of the third W-phase upper bridge resistor R53. The W-phase lower bridge arm circuit includes a W-phase lower bridge diode D32, a first W-phase lower bridge resistor R54, a second W-phase lower bridge resistor R55, a third W-phase lower bridge resistor R56, and a W-phase lower bridge MOSFET Q42. The cathode of the W-phase lower bridge diode D32 and one end of the second W-phase lower bridge resistor R54 are both electrically connected to the LO3 pin of the driver chip. The anode of the W-phase lower bridge diode D32 is electrically connected to one end of the first W-phase lower bridge resistor R54, and the other end of the first W-phase lower bridge resistor R54 is electrically connected to one end of the third W-phase lower bridge resistor R56. The source of the W-phase lower bridge MOSFET Q42 is electrically connected to the drain of the W-phase upper bridge MOSFET Q41. The gate of the W-phase lower bridge MOSFET Q42 is electrically connected to the other end of the second W-phase lower bridge resistor R55. The drain of the W-phase lower bridge MOSFET Q42 is electrically connected to the other end of the third W-phase lower bridge resistor R56, forming the common terminal COM of the lower bridge arm circuit. When the microcontroller outputs an enable signal, the enable input port of the driver chip remains at a high level. This turns off the U-phase upper bridge MOSFET Q21, V-phase upper bridge MOSFET Q31, and W-phase upper bridge MOSFET Q41, while turning on the U-phase lower bridge MOSFET Q22, V-phase lower bridge MOSFET Q32, and W-phase lower bridge MOSFET Q42, forming a closed loop of short-circuiting the three-phase windings to ground. Example 2

[0023] like Figure 5 As shown, this embodiment provides a motor drive control method based on the motor control circuit in Embodiment 1. The method includes: Step 1: Acquire analog voltage signals or control command signals; Step 2: Determine the motor's operating state based on the analog voltage signal or control command signal; the motor's operating state includes normal operating state and braking operating state; specifically: The motor's operating state is determined based on analog voltage signals or control command signals, including: Determine the power supply voltage value based on the analog voltage signal; If the power supply voltage is lower than the preset voltage threshold, the motor will be in braking mode. If the control command signal is a stop command, the motor is in braking mode.

[0024] Step 3: If the motor is in braking mode, continuously output enable signal and action signal; It should be noted that in this embodiment, the enable signal output by the microcontroller keeps the enable input port of the driver chip at a high level and does not turn off prematurely during braking. like Figure 6 and Figure 7 As shown, the time when the power supply voltage is detected to be lower than the preset voltage threshold or a shutdown command is received is... That is, from Initially, the motor is in braking mode. When the power supply voltage stabilizes again, the motor stops, and braking ends. This time is recorded as _____. Then the motor braking time is ; Therefore, it can be seen that if the traditional braking scheme shuts off the drive chip enable in advance, it will lead to braking failure. In the method proposed in this embodiment, during motor braking, the IR2136_EN pin remains at a high level, the HO1, HO2 and HO3 pins corresponding to the upper bridge arm circuit continuously output low-level signals, and the upper bridge arm circuit is turned off; the LO1, LO2 and LO3 pins corresponding to the lower bridge arm circuit continuously output high-level signals, and the lower bridge arm circuit is turned on. The upper bridge arm circuit is closed, and the lower bridge arm circuit is opened, thus forming a closed circuit to ground, and the motor generates reverse braking torque.

[0025] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature.

[0026] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A motor control circuit, characterized in that, include: The power supply voltage detection unit is used to detect the power supply voltage and output an analog voltage signal. A microcontroller, connected to the power supply voltage detection unit, is used to receive analog voltage signals or control command signals and output an enable signal. The three-phase half-bridge circuit unit includes a U-phase half-bridge circuit for outputting U-phase voltage, a V-phase half-bridge circuit for outputting V-phase voltage, and a W-phase half-bridge circuit for outputting W-phase voltage. Each phase half-bridge circuit is connected to the corresponding motor phase voltage input port; each phase half-bridge circuit includes a connected upper bridge arm circuit and a lower bridge arm circuit. The half-bridge drive unit is connected to the microcontroller and the three-phase half-bridge circuit unit. It is used to turn off the upper bridge arm circuit and turn on the lower bridge arm circuit according to the enable signal, forming a closed loop shorted to ground, so that the motor generates reverse braking torque.

2. The motor control circuit according to claim 1, characterized in that, The microcontroller also outputs action signals; The half-bridge drive unit includes a drive chip, a shielding circuit, and a sampling circuit; The sampling circuit is connected to the driver chip through the shielding circuit; The driver chip is connected to the upper bridge arm circuit and the lower bridge arm circuit; The sampling circuit is connected to the lower bridge arm circuit; The sampling circuit is used to sample the voltage of the lower bridge arm circuit and output the sampled voltage to the driver chip through the shielding circuit. The shielding circuit is used to switch the connection state between the sampling circuit and the driver chip according to the action signal.

3. The motor control circuit according to claim 2, characterized in that, The driver chip is equipped with an enable input port, a detection port, and six output ports; The enable input port is connected to the microcontroller and is used to receive the enable signal; The detection port is connected to the shielding circuit and is used to input the sampling voltage; The six output ports are respectively connected to the upper and lower bridge arm circuits of each phase half-bridge circuit.

4. The motor control circuit according to claim 2, characterized in that, The shielding circuit includes a first shielding MOSFET, a second shielding MOSFET, a first shielding resistor, and a second shielding resistor; The source of the first shielded MOS transistor is connected to a power supply, the gate of the first shielded MOS transistor is connected to an action signal, and the drain of the first shielded MOS transistor is connected to one end of the first shielding resistor. The other end of the first shielding resistor is grounded; The gate of the second shielded MOS transistor is connected to the sampling circuit; the source of the second shielded MOS transistor is connected to the drain of the first shielded MOS transistor; and the drain of the second shielded MOS transistor is connected to one end of the second shielding resistor and the driving chip, respectively. The other end of the second shielding resistor is grounded.

5. The motor control circuit according to claim 4, characterized in that, The sampling circuit includes a sampling capacitor, a first sampling resistor, a second sampling resistor, and a third sampling resistor; One end of the sampling capacitor is connected to one end of the first sampling resistor and one end of the third sampling resistor, respectively; The other end of the sampling capacitor is connected to the gate of the second shielded MOS transistor, the other end of the first sampling resistor, and one end of the second sampling resistor, respectively. The other end of the second sampling resistor and the other end of the third sampling resistor are both connected to the lower bridge arm circuit.

6. The motor control circuit according to claim 2, characterized in that, The upper bridge arm circuit includes an upper bridge diode, a first upper bridge resistor, a second upper bridge resistor, a third upper bridge resistor, and an upper bridge MOSFET; The cathode of the upper bridge diode and one end of the second upper bridge resistor are both connected to the driving chip. The anode of the upper bridge diode is connected to one end of the first upper bridge resistor, and the other end of the first upper bridge resistor is connected to one end of the third upper bridge resistor. The source of the upper bridge MOSFET is connected to the power supply, the gate of the upper bridge MOSFET is connected to the other end of the second upper bridge resistor, and the drain of the upper bridge MOSFET is connected to the other end of the third upper bridge resistor. The lower bridge arm circuit includes a lower bridge diode, a first lower bridge resistor, a second lower bridge resistor, a third lower bridge resistor, and a lower bridge MOSFET; The cathode of the lower bridge diode and one end of the second lower bridge resistor are both connected to the driver chip. The anode of the lower bridge diode is connected to one end of the first lower bridge resistor, and the other end of the first lower bridge resistor is connected to one end of the third lower bridge resistor. The source of the lower bridge MOS transistor is connected to the drain of the upper bridge MOS transistor, the gate of the lower bridge MOS transistor is connected to the other end of the second lower bridge resistor, and the drain of the lower bridge MOS transistor is connected to the other end of the third lower bridge resistor.

7. A motor drive control method, characterized in that, Based on the motor control circuit according to any one of claims 1 to 6, the method includes: Acquire analog voltage signals or control command signals; The motor operating state is determined based on the analog voltage signal or control command signal; wherein the motor operating state includes normal operating state and braking operating state; If the motor is in braking mode, it will continuously output enable and action signals.

8. The motor drive control method according to claim 7, characterized in that, Determining the motor's operating state based on analog voltage signals or control command signals includes: Determine the power supply voltage value based on the analog voltage signal; If the power supply voltage is lower than the preset voltage threshold, the motor will be in braking mode.

9. The motor drive control method according to claim 7, characterized in that, The step of determining the motor operating state based on analog voltage signals or control command signals also includes: If the control command signal is a stop command, the motor is in braking mode.

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