A three-phase motor power drive circuit

Abstract

The application provides a three-phase motor power driving circuit. It belongs to the technical field of motor driving and comprises a driving module, a voltage detection circuit and a forward circuit. The driving module comprises a first bridge arm, a second bridge arm and a third bridge arm. Each bridge arm comprises a branch formed by a P-type MOS tube and an N-type MOS tube, the P-type MOS tube and the N-type MOS tube are connected, the gate of the P-type MOS tube on each bridge arm is connected with an N-type triode for driving the P-type MOS tube, and each bridge arm is connected to a load. The N-type triode is used for driving the P-type MOS tube, a fast rising edge and a falling edge are provided, the high-side driving of the alternating current motor is realized, the power loss is reduced, and the driver device is saved. The voltage detection circuit can detect the voltage input into the driving module. The transformer magnetic flux can be reset and adjusted through the PWM pulse, and the transformer voltage can be adjusted through the magnetic flux.

Description

Technical Field

[0001] This utility model belongs to the field of motor drive technology, and specifically relates to a three-phase motor power drive circuit. Background Technology

[0002] Three-phase motor drive circuits are key to the operation and control of AC motors. Most three-phase motor drive circuits for AC motors are based on three-phase inverter bridges. However, due to different switching devices, there are differences in the power loss and switching speed of the inverter bridge.

[0003] Existing three-phase motor drive circuits with voltages below 30 volts are mostly composed of 6 N-channel MOSFETs. NMOS devices are more common in low-side switching applications because they can be directly driven by logic levels.

[0004] However, when NMOS is used in high-side switching applications, a drive signal higher than the supply voltage must be provided, which usually requires an additional charge pump or high-voltage drive, increasing design complexity and cost, which also reflects the limitations of NMOS. Summary of the Invention

[0005] In view of the above problems, this utility model proposes a three-phase motor power drive circuit. It can be directly applied to the high-side switch drive of AC motors with voltages up to 30 volts, saving the cost of drive components and reducing electromagnetic interference and power loss.

[0006] This application provides a three-phase motor power drive circuit, including: Drive module, voltage detection circuit and forward converter circuit; The drive module includes a first bridge arm, a second bridge arm, and a third bridge arm; Each bridge arm includes a branch formed by a P-type MOS transistor and an N-type MOS transistor. The P-type MOS transistor and the N-type MOS transistor are connected. The gate of the P-type MOS transistor on each bridge arm is connected to an N-type transistor that drives the P-type MOS transistor. Each bridge arm is connected to the load. The input terminal of the voltage detection circuit is connected to a forward converter, and the output terminal is connected to a driver module. The enable terminal and the voltage detection terminal of the voltage detection circuit are connected to a microcontroller (MCU). A forward converter circuit is provided, wherein the input terminal of the forward converter circuit is connected to a power supply, and the output terminal is connected to a voltage detection circuit and a drive module; an isolation transformer is connected between the input terminal and the output terminal of the forward converter circuit, and the isolation transformer is connected to a flux adjustment branch and a power supply branch.

[0007] Preferably, the first bridge arm includes: The first P-type MOSFET Q1, the second N-type MOSFET Q2, the seventh N-type transistor Q7, the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4; The source of the first P-type MOSFET Q1 is connected to the positive terminal of the power supply, the drain of the first P-type MOSFET Q1 is connected to the drain of the second N-type MOSFET Q2, the gate of the first P-type MOSFET Q1 is connected to the collector of the seventh N-type MOSFET Q7, and the gate of the first P-type MOSFET Q1 is also connected to the second terminal of the third resistor R3, the first terminal of the third resistor R3 is connected to the positive terminal of the power supply. The gate of the second N-type MOSFET Q2 is connected to the PWM signal. A fourth resistor R4 is connected between the gate and the source of the second N-type MOSFET Q2. The source of the second N-type MOSFET Q2 is grounded. The collector of the seventh N-type transistor Q7 is connected to the gate of the first P-type MOSFET Q1 and the second terminal of the third resistor R3. The emitter and base of the seventh N-type transistor Q7 are connected by a second resistor R2, and the emitter of the seventh N-type transistor Q7 is grounded. The base of the seventh N-type transistor Q7 is connected to the second terminal of the first resistor R1, and the first terminal of the first resistor R1 is connected to the PWM signal. A terminal is led out between the drain of the first P-type MOSFET Q1 and the drain of the second N-type MOSFET Q2 to connect to the load.

[0008] Preferably, the second bridge arm includes: The third P-type MOSFET Q3, the fourth N-type MOSFET Q4, the eighth N-type transistor Q8, the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, and the eighth resistor R8; The source of the third P-type MOSFET Q3 is connected to the positive terminal of the power supply, the drain of the third P-type MOSFET Q3 is connected to the drain of the fourth N-type MOSFET Q4, the gate of the third P-type MOSFET Q3 is connected to the collector of the seventh N-type MOSFET Q7, and the gate of the third P-type MOSFET Q3 is also connected to the second terminal of the seventh resistor R7, the first terminal of the seventh resistor R7 is connected to the positive terminal of the power supply. The gate of the fourth N-type MOSFET Q4 is connected to the PWM signal. The eighth resistor R8 is connected between the gate and the source of the fourth N-type MOSFET Q4, and the source of the fourth N-type MOSFET Q4 is grounded. The collector of the eighth N-type transistor Q8 is connected to the gate of the third P-type MOSFET Q3 and the second terminal of the seventh resistor R7. The emitter and base of the eighth N-type transistor Q8 are connected by the sixth resistor R6, and the emitter of the eighth N-type transistor Q8 is grounded. The base of the eighth N-type transistor Q8 is connected to the second terminal of the fifth resistor R5, and the first terminal of the fifth resistor R5 is connected to the PWM signal. A terminal is led out between the drain of the third P-type MOSFET Q3 and the drain of the fourth N-type MOSFET Q4 to connect the load.

[0009] Preferably, the third bridge arm includes: The fifth P-type MOSFET Q5, the sixth N-type MOSFET Q6, the ninth N-type transistor Q9, the ninth resistor R9, the tenth resistor R10, the eleventh resistor R11, and the twelfth resistor R12; The source of the fifth P-type MOSFET Q5 is connected to the positive terminal of the power supply, the drain of the fifth P-type MOSFET Q5 is connected to the drain of the sixth N-type MOSFET Q6, the gate of the fifth P-type MOSFET Q5 is connected to the collector of the seventh N-type MOSFET Q7, and the gate of the fifth P-type MOSFET Q5 is also connected to the second end of the eleventh resistor R11, the first end of the eleventh resistor R11 is connected to the positive terminal of the power supply. The gate of the sixth N-type MOSFET Q6 is connected to the PWM signal. The twelfth resistor R12 is connected between the gate and the source of the sixth N-type MOSFET Q6. The source of the sixth N-type MOSFET Q6 is grounded. The collector of the ninth N-type transistor Q9 is connected to the gate of the fifth P-type MOSFET Q5 and the second terminal of the eleventh resistor R11. The emitter and base of the ninth N-type transistor Q9 are connected by the tenth resistor R10, and the emitter of the ninth N-type transistor Q9 is grounded. The base of the ninth N-type transistor Q9 is connected to the second terminal of the ninth resistor R9, and the first terminal of the ninth resistor R9 is connected to the PWM signal. A terminal is led out between the drain of the fifth P-type MOSFET Q5 and the drain of the sixth N-type MOSFET Q6 to connect the load.

[0010] Preferably, the voltage detection circuit includes: The eleventh P-type MOSFET Q11, the thirteenth resistor R13, the fourteenth resistor R14, the fifteenth resistor R15, and the fourth capacitor C4; The source of the eleventh P-type MOSFET Q11 is connected to the positive terminal of the power supply, and the gate of the eleventh P-type MOSFET Q11 is connected to the second terminal of the fifteenth resistor R15. The first terminal of the fifteenth resistor R15 is connected to the positive terminal of the power supply, and the drain of the eleventh P-type MOSFET Q11 is connected to the first terminal of the thirteenth resistor R13. The second terminal of the thirteenth resistor R13 is connected to the first terminal of the fourteenth resistor R14, and the second terminal of the fourteenth resistor R14 is grounded. The fourth capacitor C4 is connected in parallel across the fourteenth resistor R14, and the first terminal of the fourth capacitor C4 is connected to the detection terminal AD terminal and then to the microcontroller MCU.

[0011] Preferably, the voltage detection circuit further includes: The twelfth N-type transistor Q12, the fourth Zener diode D4, the sixteenth resistor R16, and the seventeenth resistor R17; The collector of the twelfth N-type transistor Q12 is connected to the second terminal of the sixteenth resistor R16, and the first terminal of the sixteenth resistor R16 is connected to the second terminal of the fifteenth resistor R15 and the gate of the eleventh P-type MOSFET Q11. The emitter and base of the 12th N-type transistor Q12 are connected by the 17th resistor R17, and the second terminal of the emitter of the 12th N-type transistor Q12 and the 17th resistor R17 is grounded. The base of the 12th N-type transistor Q12 is connected to the enable terminal EN through the fourth Zener diode D4. The cathode of the fourth Zener diode D4 is connected to the base of the 12th N-type transistor Q12, and the anode of the fourth Zener diode D4 is connected to the microcontroller MCU as the enable terminal.

[0012] Preferably, the forward converter circuit includes: First transformer U1, first capacitor C1, first diode D1 The first transformer U1 includes a first excitation coil N1, a second excitation coil N2, and a third excitation coil N3; The first capacitor C1 is connected between the positive terminal of the power supply and the ground terminal. The first end of the first excitation coil N1 is connected to the positive terminal of the power supply, and the second end of the first excitation coil N1 is connected to the negative terminal of the first diode D1. The positive terminal of the first diode D1 is grounded.

[0013] Preferably, the forward converter circuit further includes: A flux regulation branch, wherein the flux regulation branch includes a tenth type N MOS transistor Q10; The drain of the tenth N-type MOSFET Q10 is connected to the second terminal of the second excitation coil N2, the source of the tenth N-type MOSFET Q10 is grounded, and the gate of the tenth N-type MOSFET Q10 is connected to the microcontroller MCU that provides the PWM pulse signal.

[0014] Preferably, the forward converter circuit further includes: The power supply branch includes: a second diode D2, a third diode D3, and a first inductor L1; The positive terminal of the second diode D2 is connected to the first end of the third excitation coil N3; The cathode of the second diode D2 is connected to the cathode of the third diode D3 and to the first terminal of the first inductor L1; The positive terminal of the third diode D3 is connected to the second terminal of the third excitation coil and grounded.

[0015] Preferably, the power supply branch further includes: The second capacitor C2 and the third capacitor C3; The second capacitor C2 and the third capacitor C3 are connected in series. After the second capacitor C2 and the third capacitor C3 are connected in series, the first terminal of the second capacitor C2 is connected to the second terminal of the first inductor L1, and the second terminal of the third capacitor C is grounded.

[0016] The beneficial effects of this utility model are: This invention uses an N-type transistor to drive a P-type MOSFET, providing fast rising and falling edges, enabling high-side driving of AC motors, reducing power loss, and saving driving devices; this application provides a voltage detection circuit that can detect the voltage of the input drive module; the transformer flux can be reset and adjusted through PWM pulses, thereby realizing the regulation of the transformer voltage through the flux.

[0017] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objectives and other advantages of this invention can be realized and obtained through the structures pointed out in the description and the accompanying drawings. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic diagram of a three-phase motor power drive circuit is shown. Figure 2 A topology diagram of a three-phase motor power drive circuit is shown. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0021] It should be noted that the terms "first," "second," etc., used in this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," "longitudinal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings.

[0022] This application provides a three-phase motor power drive circuit, see [link to relevant documentation] Figure 1 ,include: The system comprises a drive module, a voltage detection circuit, and a forward converter. The drive module includes a first bridge arm, a second bridge arm, and a third bridge arm. Each bridge arm includes a branch formed by a P-type MOSFET and an N-type MOSFET, which are connected together. The gate of the P-type MOSFET on each bridge arm is connected to an N-type transistor that drives the P-type MOSFET. Each bridge arm is connected to a load. The input terminal of the voltage detection circuit is connected to the forward converter, and the output terminal is connected to the drive module. The enable terminal and the voltage detection terminal of the voltage detection circuit are connected to a microcontroller (MCU). The input terminal of the forward converter is connected to a power supply, and the output terminal is connected to both the voltage detection circuit and the drive module. An isolation transformer is connected between the input and output terminals of the forward converter. The isolation transformer is connected to a flux adjustment branch and a power supply branch.

[0023] It should be noted that, in this application, the positive power supply terminal in the circuit topology diagram can be understood as the positive power supply terminal of the power input end, or as the positive power supply terminal for each circuit branch or module after processing. Therefore, the positive power supply terminal referred to in this application can be understood in this way, and is not the absolute positive power supply terminal of the input power. The microcontroller MCU in this application is used to provide PWM pulse signals or to detect the voltage in the circuit of this application, and its specific structure is not specifically limited.

[0024] Specifically, the first bridge arm of the drive module in this application, see [link to relevant documentation]. Figure 2 ,include: The first P-type MOSFET Q1, the second N-type MOSFET Q2, the seventh N-type transistor Q7, the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4; The source of the first P-type MOSFET Q1 is connected to the positive terminal of the power supply, the drain of the first P-type MOSFET Q1 is connected to the drain of the second N-type MOSFET Q2, the gate of the first P-type MOSFET Q1 is connected to the collector of the seventh N-type MOSFET Q7, and the gate of the first P-type MOSFET Q1 is also connected to the second terminal of the third resistor R3, the first terminal of the third resistor R3 is connected to the positive terminal of the power supply. The gate of the second N-type MOSFET Q2 is connected to the PWM signal. A fourth resistor R4 is connected between the gate and the source of the second N-type MOSFET Q2. The source of the second N-type MOSFET Q2 is grounded. The collector of the seventh N-type transistor Q7 is connected to the gate of the first P-type MOSFET Q1 and the second terminal of the third resistor R3. The emitter and base of the seventh N-type transistor Q7 are connected by a second resistor R2, and the emitter of the seventh N-type transistor Q7 is grounded. The base of the seventh N-type transistor Q7 is connected to the second terminal of the first resistor R1, and the first terminal of the first resistor R1 is connected to the PWM signal. A terminal is led out between the drain of the first P-type MOSFET Q1 and the drain of the second N-type MOSFET Q2 to connect to the load.

[0025] Specifically, the second bridge arm of the drive module in this application, see [link to relevant documentation]. Figure 2 ,include: The third P-type MOSFET Q3, the fourth N-type MOSFET Q4, the eighth N-type transistor Q8, the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, and the eighth resistor R8; The source of the third P-type MOSFET Q3 is connected to the positive terminal of the power supply, the drain of the third P-type MOSFET Q3 is connected to the drain of the fourth N-type MOSFET Q4, the gate of the third P-type MOSFET Q3 is connected to the collector of the seventh N-type MOSFET Q7, and the gate of the third P-type MOSFET Q3 is also connected to the second terminal of the seventh resistor R7, the first terminal of the seventh resistor R7 is connected to the positive terminal of the power supply. The gate of the fourth N-type MOSFET Q4 is connected to the PWM signal. The eighth resistor R8 is connected between the gate and the source of the fourth N-type MOSFET Q4, and the source of the fourth N-type MOSFET Q4 is grounded. The collector of the eighth N-type transistor Q8 is connected to the gate of the third P-type MOSFET Q3 and the second terminal of the seventh resistor R7. The emitter and base of the eighth N-type transistor Q8 are connected by the sixth resistor R6, and the emitter of the eighth N-type transistor Q8 is grounded. The base of the eighth N-type transistor Q8 is connected to the second terminal of the fifth resistor R5, and the first terminal of the fifth resistor R5 is connected to the PWM signal. A terminal is led out between the drain of the third P-type MOSFET Q3 and the drain of the fourth N-type MOSFET Q4 to connect the load.

[0026] Specifically, the third bridge arm of the driver module in this application, see [link to relevant documentation]. Figure 2 This includes: the fifth P-type MOSFET Q5, the sixth N-type MOSFET Q6, the ninth N-type transistor Q9, the ninth resistor R9, the tenth resistor R10, the eleventh resistor R11, and the twelfth resistor R12; The source of the fifth P-type MOSFET Q5 is connected to the positive terminal of the power supply, the drain of the fifth P-type MOSFET Q5 is connected to the drain of the sixth N-type MOSFET Q6, the gate of the fifth P-type MOSFET Q5 is connected to the collector of the seventh N-type MOSFET Q7, and the gate of the fifth P-type MOSFET Q5 is also connected to the second end of the eleventh resistor R11, the first end of the eleventh resistor R11 is connected to the positive terminal of the power supply. The gate of the sixth N-type MOSFET Q6 is connected to the PWM signal. The twelfth resistor R12 is connected between the gate and the source of the sixth N-type MOSFET Q6. The source of the sixth N-type MOSFET Q6 is grounded. The collector of the ninth N-type transistor Q9 is connected to the gate of the fifth P-type MOSFET Q5 and the second terminal of the eleventh resistor R11. The emitter and base of the ninth N-type transistor Q9 are connected by the tenth resistor R10, and the emitter of the ninth N-type transistor Q9 is grounded. The base of the ninth N-type transistor Q9 is connected to the second terminal of the ninth resistor R9, and the first terminal of the ninth resistor R9 is connected to the PWM signal. A terminal is led out between the drain of the fifth P-type MOSFET Q5 and the drain of the sixth N-type MOSFET Q6 to connect the load.

[0027] The following section provides a detailed description of the drive module for a three-phase motor drive circuit.

[0028] See Figure 2 The U, V, and W phase outputs of the three-phase motor drive circuit are connected to the three phases of the motor, respectively. The MOSFETs Q1 to Q6 are driven by the MCU to control the rotation of the three-phase motor. Compared with NMOS which requires a complex floating ground drive circuit, the three MOSFETs Q1, Q3, and Q5 are simpler to drive as high-side switches.

[0029] The first bridge arm will be used as an example for detailed explanation.

[0030] See Figure 2 The function of the third resistor R3 is to pull up the gate voltage of Q1 to ensure the stability of the gate voltage and avoid floating failure; the function of the first resistor R1 and the second resistor R2 is to protect the base of the seventh N-type transistor Q7; when the base of the seventh N-type transistor Q7 is given a high-level signal, it plays the role of pulling down the gate of Q1 in the circuit.

[0031] Similarly, Q3 and Q5, so that the gate signals P1, P2, P3, N1, N2 and N3 of the six MOS in the three-phase bridge circuit can all be driven by a high level, reducing the driving cost.

[0032] Detailed Operation of Three-Phase Bridge: Since the three-phase power output by the three-phase bridge has a phase difference of 120°, the operation of this circuit can be explained in 6 stages.

[0033] Stage 1: Q1 and Q4 are on; Stage 2: Q1 and Q6 are on; Stage 3: Q3 and Q6 are on; Stage 4: Q3 and Q2 are on; Stage 5: Q5 and Q2 are on; Stage 6: Q5 and Q4 are on.

[0034] The drive circuit in this invention is applicable to driving low-to-medium power motors with a voltage of 30V or less.

[0035] In some specific implementations, the voltage detection circuit, see [link to relevant documentation]. Figure 2 ,include: The eleventh P-type MOSFET Q11, the thirteenth resistor R13, the fourteenth resistor R14, the fifteenth resistor R15, and the fourth capacitor C4; The source of the eleventh P-type MOSFET Q11 is connected to the positive terminal of the power supply, and the gate of the eleventh P-type MOSFET Q11 is connected to the second terminal of the fifteenth resistor R15. The first terminal of the fifteenth resistor R15 is connected to the positive terminal of the power supply, and the drain of the eleventh P-type MOSFET Q11 is connected to the first terminal of the thirteenth resistor R13. The second terminal of the thirteenth resistor R13 is connected to the first terminal of the fourteenth resistor R14, and the second terminal of the fourteenth resistor R14 is grounded. The fourth capacitor C4 is connected in parallel across the fourteenth resistor R14, and the first terminal of the fourth capacitor C4 is connected to the detection terminal AD terminal and then to the microcontroller MCU.

[0036] Specifically, the voltage detection circuit also includes: The twelfth N-type transistor Q12, the fourth Zener diode D4, the sixteenth resistor R16, and the seventeenth resistor R17; The collector of the twelfth N-type transistor Q12 is connected to the second terminal of the sixteenth resistor R16, and the first terminal of the sixteenth resistor R16 is connected to the second terminal of the fifteenth resistor R15 and the gate of the eleventh P-type MOSFET Q11. The emitter and base of the 12th N-type transistor Q12 are connected by the 17th resistor R17, and the second terminal of the emitter of the 12th N-type transistor Q12 and the 17th resistor R17 is grounded. The base of the 12th N-type transistor Q12 is connected to the enable terminal EN through the fourth Zener diode D4. The cathode of the fourth Zener diode D4 is connected to the base of the 12th N-type transistor Q12, and the anode of the fourth Zener diode D4 is connected to the microcontroller MCU as the enable terminal.

[0037] Specifically, in this application, the voltage detection circuit is powered by the output of the front-end forward converter. Q11 is used to achieve low power consumption, turning on when voltage detection is needed and turning off when voltage detection is not needed, thus flexibly controlling the voltage detection requirements.

[0038] The function of R15 is to pull up the gate voltage of Q11, providing a bias voltage for the MOS transistor, ensuring the stability of the gate voltage and preventing it from floating and failing. The enable terminal EN is directly connected to the MCU's I / O port, and the detection terminal AD is directly connected to the MCU's ADC port. When the circuit needs voltage detection, when the MCU outputs a signal to pull EN high, transistor Q12 conducts. The resistance value of R15 is set to 10 times that of R16. At this time, Q11 conducts, and the gate voltage of Q11 is 1 / 10 of the VCC voltage. The MCU detects the voltage through the AD port. The resistance value of R13 is several times that of R14. R13 and R14 can perform voltage division, reducing the voltage detected by the AD port by a factor of two. Voltage detection and regulation are achieved through PWM signals.

[0039] Specifically, the AD port feeds back the analog signal in the circuit to the ADC port of the MCU, and the MCU converts the circuit signal into a monitorable digital signal. When the voltage is detected to be higher than 30V, the MCU controls the PWM duty cycle of Q10 to reduce it. Similarly, when the voltage is too low, the MCU controls the PWM duty cycle of Q10 to increase it, thereby realizing real-time monitoring and adjustment of the circuit voltage.

[0040] In some specific implementation methods, see Figure 2 The forward converter circuit includes: First transformer U1, first capacitor C1, first diode D1 The first transformer U1 includes a first excitation coil N1, a second excitation coil N2, and a third excitation coil N3; The first capacitor C1 is connected between the positive terminal of the power supply and the ground terminal. The first end of the first excitation coil N1 is connected to the positive terminal of the power supply, and the second end of the first excitation coil N1 is connected to the negative terminal of the first diode D1. The positive terminal of the first diode D1 is grounded.

[0041] Specifically, the forward converter circuit further includes: A flux regulation branch, wherein the flux regulation branch includes a tenth type N MOS transistor Q10; The drain of the tenth N-type MOSFET Q10 is connected to the second terminal of the second excitation coil N2, the source of the tenth N-type MOSFET Q10 is grounded, and the gate of the tenth N-type MOSFET Q10 is connected to the microcontroller MCU that provides the PWM pulse signal.

[0042] Specifically, the forward converter circuit further includes: The power supply branch includes: a second diode D2, a third diode D3, and a first inductor L1; The positive terminal of the second diode D2 is connected to the first end of the third excitation coil N3; The cathode of the second diode D2 is connected to the cathode of the third diode D3 and to the first terminal of the first inductor L1; The positive terminal of the third diode D3 is connected to the second terminal of the third excitation coil and grounded.

[0043] In some specific implementation methods, see Figure 2 The power supply branch also includes: The second capacitor C2 and the third capacitor C3; The second capacitor C2 and the third capacitor C3 are connected in series. After the second capacitor C2 and the third capacitor C3 are connected in series, the first terminal of the second capacitor C2 is connected to the second terminal of the first inductor L1, and the second terminal of the third capacitor C is grounded.

[0044] Specifically, see Figure 2 In this utility model, the forward converter circuit is powered by VIN, and provides power to the downstream current detection circuit and the three-phase motor drive circuit through the transformer. The transformer also serves as an isolation power source. The PWM signal controls the on / off state of Q10, and the higher the duty cycle, the higher the transformer voltage.

[0045] When the tenth type N MOSFET Q10 is turned on, the transformer U1 transforms the voltage to charge the inductors C2 and C3 and to supply power to the downstream three-phase motor load. During this stage, the magnetic flux of the transformer core increases and the inductor current increases. When the switch Q10 is turned off, the inductors C2 and C3 supply power to the load, and the transformer U1 performs a magnetic reset. During this stage, the magnetic flux of the transformer core decreases to 1 and the inductor current decreases.

[0046] After Q10 is turned on, the primary side and magnetic reset winding of transformer U1 are energized, and there is voltage on the secondary winding of the transformer. Therefore, there is voltage on the upper end of C2 and the lower end of C3. The upper end of C2 is connected to VCC of the three-phase motor drive circuit, and the lower end of C3 is connected to GND, so it can supply power to the downstream load three-phase motor.

[0047] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A three-phase motor power drive circuit, characterized in that, include: Drive module, voltage detection circuit and forward converter circuit; The drive module includes a first bridge arm, a second bridge arm, and a third bridge arm; Each bridge arm includes a branch formed by a P-type MOS transistor and an N-type MOS transistor. The P-type MOS transistor and the N-type MOS transistor are connected. The gate of the P-type MOS transistor on each bridge arm is connected to an N-type transistor that drives the P-type MOS transistor. Each bridge arm is connected to the load. The input terminal of the voltage detection circuit is connected to a forward converter, and the output terminal is connected to a driver module. The enable terminal and the voltage detection terminal of the voltage detection circuit are connected to a microcontroller (MCU). A forward converter circuit is provided, wherein the input terminal of the forward converter circuit is connected to a power supply, and the output terminal is connected to a voltage detection circuit and a drive module; an isolation transformer is connected between the input terminal and the output terminal of the forward converter circuit, and the isolation transformer is connected to a flux adjustment branch and a power supply branch.

2. The driving circuit according to claim 1, characterized in that, The first bridge arm includes: The first P-type MOSFET Q1, the second N-type MOSFET Q2, the seventh N-type transistor Q7, the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4; The source of the first P-type MOSFET Q1 is connected to the positive terminal of the power supply, the drain of the first P-type MOSFET Q1 is connected to the drain of the second N-type MOSFET Q2, the gate of the first P-type MOSFET Q1 is connected to the collector of the seventh N-type MOSFET Q7, and the gate of the first P-type MOSFET Q1 is also connected to the second terminal of the third resistor R3, the first terminal of the third resistor R3 is connected to the positive terminal of the power supply. The gate of the second N-type MOSFET Q2 is connected to the PWM signal. A fourth resistor R4 is connected between the gate and the source of the second N-type MOSFET Q2. The source of the second N-type MOSFET Q2 is grounded. The collector of the seventh N-type transistor Q7 is connected to the gate of the first P-type MOSFET Q1 and the second terminal of the third resistor R3. The emitter and base of the seventh N-type transistor Q7 are connected by a second resistor R2, and the emitter of the seventh N-type transistor Q7 is grounded. The base of the seventh N-type transistor Q7 is connected to the second terminal of the first resistor R1, and the first terminal of the first resistor R1 is connected to the PWM signal. A terminal is led out between the drain of the first P-type MOSFET Q1 and the drain of the second N-type MOSFET Q2 to connect to the load.

3. The driving circuit according to claim 1, characterized in that, The second bridge arm includes: The third P-type MOSFET Q3, the fourth N-type MOSFET Q4, the eighth N-type transistor Q8, the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, and the eighth resistor R8; The source of the third P-type MOSFET Q3 is connected to the positive terminal of the power supply, the drain of the third P-type MOSFET Q3 is connected to the drain of the fourth N-type MOSFET Q4, the gate of the third P-type MOSFET Q3 is connected to the collector of the seventh N-type MOSFET Q7, and the gate of the third P-type MOSFET Q3 is also connected to the second terminal of the seventh resistor R7, the first terminal of the seventh resistor R7 is connected to the positive terminal of the power supply. The gate of the fourth N-type MOSFET Q4 is connected to the PWM signal. The eighth resistor R8 is connected between the gate and the source of the fourth N-type MOSFET Q4, and the source of the fourth N-type MOSFET Q4 is grounded. The collector of the eighth N-type transistor Q8 is connected to the gate of the third P-type MOSFET Q3 and the second terminal of the seventh resistor R7. The emitter and base of the eighth N-type transistor Q8 are connected by the sixth resistor R6, and the emitter of the eighth N-type transistor Q8 is grounded. The base of the eighth N-type transistor Q8 is connected to the second terminal of the fifth resistor R5, and the first terminal of the fifth resistor R5 is connected to the PWM signal. A terminal is led out between the drain of the third P-type MOSFET Q3 and the drain of the fourth N-type MOSFET Q4 to connect the load.

4. The driving circuit according to claim 1, characterized in that, The third bridge arm includes: The fifth P-type MOSFET Q5, the sixth N-type MOSFET Q6, the ninth N-type transistor Q9, the ninth resistor R9, the tenth resistor R10, the eleventh resistor R11, and the twelfth resistor R12; The source of the fifth P-type MOSFET Q5 is connected to the positive terminal of the power supply, the drain of the fifth P-type MOSFET Q5 is connected to the drain of the sixth N-type MOSFET Q6, the gate of the fifth P-type MOSFET Q5 is connected to the collector of the seventh N-type MOSFET Q7, and the gate of the fifth P-type MOSFET Q5 is also connected to the second end of the eleventh resistor R11, the first end of the eleventh resistor R11 is connected to the positive terminal of the power supply. The gate of the sixth N-type MOSFET Q6 is connected to the PWM signal. The twelfth resistor R12 is connected between the gate and the source of the sixth N-type MOSFET Q6. The source of the sixth N-type MOSFET Q6 is grounded. The collector of the ninth N-type transistor Q9 is connected to the gate of the fifth P-type MOSFET Q5 and the second terminal of the eleventh resistor R11. The emitter and base of the ninth N-type transistor Q9 are connected by the tenth resistor R10, and the emitter of the ninth N-type transistor Q9 is grounded. The base of the ninth N-type transistor Q9 is connected to the second terminal of the ninth resistor R9, and the first terminal of the ninth resistor R9 is connected to the PWM signal. A terminal is led out between the drain of the fifth P-type MOSFET Q5 and the drain of the sixth N-type MOSFET Q6 to connect the load.

5. The driving circuit according to any one of claims 1 to 4, characterized in that, Voltage detection circuit, including: The eleventh P-type MOSFET Q11, the thirteenth resistor R13, the fourteenth resistor R14, the fifteenth resistor R15, and the fourth capacitor C4; The source of the eleventh P-type MOSFET Q11 is connected to the positive terminal of the power supply, and the gate of the eleventh P-type MOSFET Q11 is connected to the second terminal of the fifteenth resistor R15. The first terminal of the fifteenth resistor R15 is connected to the positive terminal of the power supply, and the drain of the eleventh P-type MOSFET Q11 is connected to the first terminal of the thirteenth resistor R13. The second terminal of the thirteenth resistor R13 is connected to the first terminal of the fourteenth resistor R14, and the second terminal of the fourteenth resistor R14 is grounded. The fourth capacitor C4 is connected in parallel across the fourteenth resistor R14, and the first terminal of the fourth capacitor C4 is connected to the detection terminal AD terminal and then to the microcontroller MCU.

6. The driving circuit according to claim 5, characterized in that, The voltage detection circuit further includes: The twelfth N-type transistor Q12, the fourth Zener diode D4, the sixteenth resistor R16, and the seventeenth resistor R17; The collector of the twelfth N-type transistor Q12 is connected to the second terminal of the sixteenth resistor R16, and the first terminal of the sixteenth resistor R16 is connected to the second terminal of the fifteenth resistor R15 and the gate of the eleventh P-type MOSFET Q11. The emitter and base of the 12th N-type transistor Q12 are connected by the 17th resistor R17, and the second terminal of the emitter of the 12th N-type transistor Q12 and the 17th resistor R17 is grounded. The base of the 12th N-type transistor Q12 is connected to the enable terminal EN through the fourth Zener diode D4. The cathode of the fourth Zener diode D4 is connected to the base of the 12th N-type transistor Q12, and the anode of the fourth Zener diode D4 is connected to the microcontroller MCU as the enable terminal.

7. The driving circuit according to any one of claims 1 to 4, characterized in that, The forward converter circuit includes: First transformer U1, first capacitor C1, first diode D1 The first transformer U1 includes a first excitation coil N1, a second excitation coil N2, and a third excitation coil N3; The first capacitor C1 is connected between the positive terminal of the power supply and the ground terminal. The first end of the first excitation coil N1 is connected to the positive terminal of the power supply, and the second end of the first excitation coil N1 is connected to the negative terminal of the first diode D1. The positive terminal of the first diode D1 is grounded.

8. The driving circuit according to claim 7, characterized in that, The forward converter circuit further includes: A flux regulation branch, wherein the flux regulation branch includes a tenth type N MOS transistor Q10; The drain of the tenth N-type MOSFET Q10 is connected to the second terminal of the second excitation coil N2, the source of the tenth N-type MOSFET Q10 is grounded, and the gate of the tenth N-type MOSFET Q10 is connected to the microcontroller MCU that provides the PWM pulse signal.

9. The driving circuit according to claim 8, characterized in that, The forward converter circuit further includes: The power supply branch includes: a second diode D2, a third diode D3, and a first inductor L1; The positive terminal of the second diode D2 is connected to the first end of the third excitation coil N3; The cathode of the second diode D2 is connected to the cathode of the third diode D3 and to the first terminal of the first inductor L1; The positive terminal of the third diode D3 is connected to the second terminal of the third excitation coil and grounded.

10. The driving circuit according to claim 9, characterized in that, The power supply branch also includes: The second capacitor C2 and the third capacitor C3; The second capacitor C2 and the third capacitor C3 are connected in series. After the second capacitor C2 and the third capacitor C3 are connected in series, the first terminal of the second capacitor C2 is connected to the second terminal of the first inductor L1, and the second terminal of the third capacitor C is grounded.

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