Motor control circuit with low surge current

Abstract

The utility model provides a motor control circuit with low surge current, which relates to the technical field of motor and cooling fan control, and comprises a surge suppression module, a voltage conversion module, an MCU (Microprogrammed Control Unit) control module, a half-bridge control module and a motor driving module, the surge suppression module is electrically connected with the voltage conversion module and the MCU control module respectively, and the half-bridge control module is electrically connected with the motor driving module. The surge suppression module comprises a rectification filtering unit and an MOS tube soft switching unit, the rectification filtering unit is electrically connected with the MOS tube soft switching unit and the MCU control module and is used for converting AC voltage into DC voltage, and the MOS tube soft switching unit is electrically connected with the voltage conversion module and is used for suppressing surge current in the motor control circuit; the voltage conversion module is electrically connected with the MCU control module and the half-bridge control module. The MCU control module is electrically connected with the half-bridge control module and the motor driving module. And the half-bridge control module is electrically connected with the motor driving module. According to the utility model, the surge current can be effectively reduced, and the damage rate of devices can be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of motor and heat dissipation fan control, in particular to a motor control circuit with low surge current. Background Art

[0002] The fan motor is easy to control and can be started by providing a certain amount of DC voltage. It is often used as a terminal in many industries such as industrial automation and refrigeration. For example, the common control modes of the controller for cooling fans include power-on start control mode, temperature switch control mode and gear speed control mode. Among them, power-on start is the simplest control method, that is, after starting the controller, a DC voltage of a constant amplitude is passed to the fan motor to make the motor run at a constant speed.

[0003] The Chinese patent application with publication number CN220511006U discloses a motor control circuit and system, which includes a main control module, a first half-bridge module, a second half-bridge module, and a current sampling module; the main control module is electrically connected to the first half-bridge module and the second half-bridge module; the first half-bridge module and the second half-bridge module are also electrically connected to the motor; the current sampling module is electrically connected to the first half-bridge module and the second half-bridge module respectively; the current sampling module is also electrically connected to the main control module; the current sampling module includes a Hall and a third switch tube, the in-phase input end of the Hall is electrically connected to the first half-bridge module and the second half-bridge module, the base of the third switch tube is electrically connected to the output end of the Hall, the collector is electrically connected to the main control module, and the emitter is grounded. However, the above scheme cannot change the voltage across the capacitor suddenly, and the DC high voltage will directly charge the large capacitor device, which will generate a surge current of tens to hundreds of amperes, making the connected rectifier bridge easy to break down and damage, and the relay contacts stick. Therefore, it is very necessary to provide a motor control circuit with low surge current to effectively reduce surge current and reduce device damage rate. Utility Model Content

[0004] In view of this, the utility model proposes a motor control circuit with low surge current. After the rectifier and filter unit completes the conversion of AC voltage into DC voltage, the DC voltage can suppress the surge current in the MOS tube soft switch unit, which can effectively reduce the surge current and reduce the device damage rate.

[0005] The utility model provides a motor control circuit with low surge current, including a surge suppression module, a voltage conversion module, an MCU control module, a half-bridge control module and a motor drive module, wherein:

[0006] The surge suppression module is electrically connected to the voltage conversion module and the MCU control module respectively, and the surge suppression module includes a rectifier filter unit and a MOS tube soft switch unit, and the rectifier filter unit is electrically connected to the MOS tube soft switch unit and the MCU control module respectively, and the rectifier filter unit is used to convert the AC voltage into a DC voltage, and the MOS tube soft switch unit is electrically connected to the voltage conversion module, and the MOS tube soft switch unit is used to suppress the surge current in the motor control circuit;

[0007] The voltage conversion module is electrically connected to the MCU control module and the half-bridge control module respectively, and is used to clamp the gate voltage of the MOS tube in the surge suppression module at 12V, and to supply power to the MCU control module and the half-bridge control module respectively;

[0008] The MCU control module is electrically connected to the half-bridge control module and the motor drive module respectively, and the MCU control module is used to send a drive signal to the half-bridge control module;

[0009] The half-bridge control module is electrically connected to the motor drive module, and the half-bridge control module is used to receive a drive signal sent by the MCU control module and drive the motor drive module according to the drive signal.

[0010] On the basis of the above technical scheme, preferably, the rectifier and filter unit includes a thermistor R32, a resistor R2, a resistor R3, a resistor R8, a resistor R9, a resistor R10, a resistor R34, a capacitor CX1, a capacitor C2, a capacitor C3, an electrolytic capacitor EC1, a diode D1, a diode D2, a diode D4, a diode D5 and a diode D11, one end of the thermistor R32 is connected to the N end of the mains, the other end of the thermistor R32 is respectively connected to one end of the resistor R2, one end of the resistor R3, one end of the capacitor CX1 and the common end of the diode D2 and the diode D3, the other end of the resistor R2 is respectively connected to the L end of the mains, the positive electrode of the diode D11, the other end of the resistor R3, the other end of the capacitor CX1 and the common end of the diode D4 and the diode D5. The common ends are connected, the common ends of the diode D1 and the diode D4, one end of the resistor R34 and the MOS tube soft switch unit are grounded together, the common ends of the diode D2 and the diode D5 are respectively connected to one end of the capacitor C2, one end of the electrolytic capacitor EC1 and the MOS tube soft switch unit, the other end of the capacitor C2 is respectively connected to the other end of the electrolytic capacitor EC1, the other end of the resistor R34 and the MOS tube soft switch unit, the cathode of the diode D11 is connected to one end of the resistor R8, the other end of the resistor R8 is connected to one end of the resistor R9, the other end of the resistor R9 and the first common end of the resistor R10 and the capacitor C3 are all connected to the MCU control module, and the second common end of the resistor R10 and the capacitor C3 is grounded.

[0011] On the basis of the above technical solution, preferably, the MOS tube soft switch unit includes a MOS tube Q5, a capacitor C14, a resistor R35, a resistor R36, a resistor R37 and a diode D12, the drain of the MOS tube Q5 is connected to the rectification and filtering unit, the source of the MOS tube Q5 is respectively connected to the rectification and filtering unit, one end of the capacitor C14 and one end of the resistor R37, the gate of the MOS tube Q5 is respectively connected to the other end of the capacitor C14, the other end of the resistor R37, one end of the resistor R36 and the positive electrode of the diode D12, the other end of the resistor R36 is connected to the rectification and filtering unit through the resistor R35, and the negative electrode of the diode D12 is connected to the voltage conversion module.

[0012] More preferably, the voltage conversion module includes a first buck unit and a second buck unit, the first buck unit is electrically connected to the second buck unit, the surge suppression module and the half-bridge control module respectively, and the second buck unit is electrically connected to the MCU control module.

[0013] Further preferably, the first step-down unit includes a power chip U6, a resistor R4, a resistor R5, a capacitor C1, an electrolytic capacitor EC2, an inductor LS1, a diode D3 and a diode D6, the first pin of the power chip U6 is respectively connected to one end of the resistor R4, the cathode of the diode D6, one end of the inductor LS1 and one end of the capacitor C1, the second pin of the power chip U6 is respectively connected to the third pin of the power chip U6, the other end of the capacitor C1 and the cathode of the diode D3, the fourth pin of the power chip U6 is connected to the surge suppression module, the fifth pin of the power chip U6 is connected to the other end of the resistor R4, the positive electrode of the diode D3 is respectively connected to the other end of the inductor LS1, one end of the resistor R5, one end of the electrolytic capacitor EC2 and the second step-down unit, and the positive electrode of the diode D6, the other end of the resistor R5 and the other end of the electrolytic capacitor EC2 are grounded together.

[0014] Further preferably, the second step-down unit includes a resistor R6, a Zener diode DZ1 and a capacitor C4, one end of the resistor R6 is connected to the first step-down unit, the other end of the resistor R6 is connected to the positive electrode of the Zener diode DZ1, one end of the capacitor C4 and the MCU control module, and the other end of the capacitor C4 and the positive electrode of the Zener diode DZ1 are grounded together.

[0015] Further preferably, the MCU control module includes an MCU chip U1, a resistor R17, a resistor R19, a resistor R22, a resistor R33, a Hall U3, a Hall U4, a capacitor C7 and a capacitor C8, a first pin of the MCU chip U1 is respectively connected to the second step-down unit and one end of the capacitor C8, the other end of the capacitor C8 is grounded, a second pin of the MCU chip U1, a third pin of the MCU chip U1, a fourth pin of the MCU chip U1 and a fifth pin of the MCU chip U1 are all connected to the half-bridge control module, a sixth pin of the MCU chip U1 is connected to the surge suppression module, and a seventh pin of the MCU chip U1 is connected to the motor drive module. The eighth pin of the MCU chip U1 is respectively connected to one end of the capacitor C7 and one end of the resistor R17, the ninth pin of the MCU chip U1 is connected to the PWM input port, the tenth pin of the MCU chip U1 and the other end of the capacitor C7 are commonly grounded, the other end of the resistor R17 is respectively connected to the third end of the Hall U3, the third end of the Hall U4 and one end of the resistor R19, the other end of the resistor R19 is respectively connected to the first end of the Hall U3, the first end of the Hall U4 and one end of the resistor R22, the second end of the Hall U3 and the second end of the Hall U4 are commonly grounded, and the other end of the resistor R22 is connected to the second step-down unit through the resistor R33.

[0016] More preferably, the motor drive module includes a resistor R7, a resistor R11, a resistor R12, a resistor R14, a resistor R16, a resistor R20, a resistor R21, a resistor R24, a resistor R26, a resistor R27, a MOS tube Q1, a MOS tube Q2, a MOS tube Q3, a MOS tube Q4, a terminal L1, a terminal L2 and a capacitor C12, one end of the resistor R7 is connected to the half-bridge control module, the other end of the resistor R7 is respectively connected to one end of the resistor R11 and the gate of the MOS tube Q1, the other end of the resistor R11 is respectively connected to the source of the MOS tube Q1, the drain of the MOS tube Q2 and the terminal L1, the drain of the MOS tube Q1 is respectively connected to the surge suppression module and the drain of the MOS tube Q3, one end of the resistor R12 is connected to the half-bridge control module, the other end of the resistor R12 is respectively connected to the gate of the MOS tube Q2 and the terminal L1, One end of the resistor R14 is connected, the other end of the resistor R14 is respectively connected to the source of the MOS tube Q2, the source of the MOS tube Q4, the other end of the resistor R24, one end of the resistor R26 and one end of the resistor R27, one end of the resistor R16 is connected to the half-bridge control module, the other end of the resistor R16 is connected to one end of the resistor R20 and the gate of the MOS tube Q3, the other end of the resistor R20 is respectively connected to the source of the MOS tube Q3, the drain of the MOS tube Q4 and the terminal L2, one end of the resistor R21 is connected to the half-bridge control module, the other end of the resistor R21 is respectively connected to one end of the resistor R24 ​​and the gate of the MOS tube Q4, the other end of the resistor R27 is grounded, the other end of the resistor R26 is respectively connected to one end of the capacitor C12 and the MCU control module, and the other end of the capacitor C12 is grounded.

[0017] The low surge current motor control circuit provided by the utility model has the following beneficial effects compared with the prior art:

[0018] (1) By setting a rectifier filter unit and a MOS tube soft switch unit in the surge suppression module, under the action of the RC buffer circuit composed of R35, R36, R37 and C14, the DS pole of the MOS tube Q5 is slowly turned on, which can effectively reduce the surge current and reduce the damage rate of the PCBA device during use, thereby improving the reliability and safety of the PCBA device, and can also effectively solve the spark phenomenon that occurs when the socket is plugged in or the spark phenomenon that occurs at the relay contact;

[0019] (2) Hall U3, Hall U4 and surrounding resistors and capacitors form a Hall detection circuit, which can achieve closed-loop control by accurately detecting the rotor position and can adjust the working state of the motor according to actual conditions, thereby improving the stability and accuracy of the motor control circuit. Diode D11, resistors R8, R9, R10 and capacitor C3 form a voltage detection circuit, which provides overload protection for the motor control circuit. At the same time, by monitoring the circuit voltage, circuit faults can be discovered in time, thereby improving the safety and reliability of the motor control circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A schematic diagram of a low surge current motor control circuit provided by the utility model;

[0022] Figure 2 A schematic diagram of a circuit of a surge suppression module provided by the utility model;

[0023] Figure 3 A circuit diagram of a voltage conversion module provided by the utility model;

[0024] Figure 4 A circuit diagram of the MCU control module provided by the utility model;

[0025] Figure 5 A circuit diagram of a half-bridge control module provided by the utility model;

[0026] Figure 6 This is a circuit diagram of the motor drive module provided by the utility model.

[0027] Explanation of the accompanying drawings: 1. surge suppression module; 11. rectifier filter unit; 12. MOS tube soft switch unit; 2. voltage conversion module; 21. first buck unit; 22. second buck unit; 3. MCU control module; 4. half-bridge control module; 5. motor drive module. DETAILED DESCRIPTION

[0028] The following will be combined with the implementation of the utility model to clearly and completely describe the technical solutions in the implementation of the utility model. Obviously, the described implementation is only a part of the implementation of the utility model, not all of the implementations. Based on the implementation of the utility model, all other implementations obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0029] The utility model discloses a motor control circuit with low surge current, referring to Figure 1 The motor control circuit includes a surge suppression module 1, a voltage conversion module 2, an MCU control module 3, a half-bridge control module 4 and a motor drive module 5, wherein:

[0030] The surge suppression module 1 is electrically connected to the voltage conversion module 2 and the MCU control module 3 respectively. The surge suppression module 1 includes a rectifier and filter unit 11 and a MOS tube soft switch unit 12. The rectifier and filter unit 11 is electrically connected to the MOS tube soft switch unit 12 and the MCU control module 3 respectively. The rectifier and filter unit 11 is used to convert AC voltage into DC voltage. The MOS tube soft switch unit 12 is electrically connected to the voltage conversion module 2. The MOS tube soft switch unit 12 is used to suppress surge current in the motor control circuit.

[0031] like Figure 2 As shown, the rectifier and filter unit 11 includes a thermistor R32, a resistor R2, a resistor R3, a resistor R8, a resistor R9, a resistor R10, a resistor R34, a capacitor CX1, a capacitor C2, a capacitor C3, an electrolytic capacitor EC1, a diode D1, a diode D2, a diode D4, a diode D5 and a diode D11, one end of the thermistor R32 is connected to the N end of the mains, the other end of the thermistor R32 is respectively connected to one end of the resistor R2, one end of the resistor R3, one end of the capacitor CX1 and the common end of the diode D2 and the diode D3, the other end of the resistor R2 is respectively connected to the L end of the mains, the positive electrode of the diode D11, the other end of the resistor R3, the other end of the capacitor CX1 and the common end of the diode D4 and the diode D5 The common end is connected, the common end of the diode D1 and the diode D4, one end of the resistor R34 and the MOS tube soft switch unit 12 are grounded together, the common end of the diode D2 and the diode D5 are respectively connected to one end of the capacitor C2, one end of the electrolytic capacitor EC1 and the MOS tube soft switch unit 12, the other end of the capacitor C2 is respectively connected to the other end of the electrolytic capacitor EC1, the other end of the resistor R34 and the MOS tube soft switch unit 12, the cathode of the diode D11 is connected to one end of the resistor R8, the other end of the resistor R8 is connected to one end of the resistor R9, the other end of the resistor R9 and the first common end of the resistor R10 and the capacitor C3 are all connected to the MCU control module 3, and the second common end of the resistor R10 and the capacitor C3 is grounded.

[0032] The MOS tube soft switch unit 12 includes a MOS tube Q5, a capacitor C14, a resistor R35, a resistor R36, a resistor R37 and a diode D12. The drain of the MOS tube Q5 is connected to the rectification and filtering unit 11, the source of the MOS tube Q5 is respectively connected to the rectification and filtering unit 11, one end of the capacitor C14 and one end of the resistor R37, the gate of the MOS tube Q5 is respectively connected to the other end of the capacitor C14, the other end of the resistor R37, one end of the resistor R36 and the positive electrode of the diode D12, the other end of the resistor R36 is connected to the rectification and filtering unit 11 through the resistor R35, and the negative electrode of the diode D12 is connected to the voltage conversion module 2.

[0033] The voltage conversion module 2 is electrically connected to the MCU control module 3 and the half-bridge control module 4 respectively. The voltage conversion module 2 is used to clamp the gate voltage of the MOS tube in the surge suppression module 1 at 12V, and to supply power to the MCU control module 3 and the half-bridge control module 4 respectively. The voltage conversion module 2 includes a first buck unit 21 and a second buck unit 22. The first buck unit 21 is electrically connected to the second buck unit 22, the surge suppression module 1 and the half-bridge control module 4 respectively, and the second buck unit 22 is electrically connected to the MCU control module 3.

[0034] like Figure 3 As shown, the first step-down unit 21 includes a power chip U6, a resistor R4, a resistor R5, a capacitor C1, an electrolytic capacitor EC2, an inductor LS1, a diode D3 and a diode D6. The first pin of the power chip U6 is respectively connected to one end of the resistor R4, the cathode of the diode D6, one end of the inductor LS1 and one end of the capacitor C1, the second pin of the power chip U6 is respectively connected to the third pin of the power chip U6, the other end of the capacitor C1 and the cathode of the diode D3, the fourth pin of the power chip U6 is connected to the surge suppression module 1, the fifth pin of the power chip U6 is connected to the other end of the resistor R4, the anode of the diode D3 is respectively connected to the other end of the inductor LS1, one end of the resistor R5, one end of the electrolytic capacitor EC2 and the second step-down unit 22, and the anode of the diode D6, the other end of the resistor R5 and the other end of the electrolytic capacitor EC2 are grounded together.

[0035] The second step-down unit 22 includes a resistor R6, a voltage-stabilizing diode DZ1 and a capacitor C4. One end of the resistor R6 is connected to the first step-down unit 21, and the other end of the resistor R6 is connected to the positive electrode of the voltage-stabilizing diode DZ1, one end of the capacitor C4 and the MCU control module 3. The other end of the capacitor C4 and the positive electrode of the voltage-stabilizing diode DZ1 are grounded together.

[0036] The MCU control module 3 is electrically connected to the half-bridge control module 4 and the motor drive module 5 respectively, and the MCU control module 3 is used to send a drive signal to the half-bridge control module 4 .

[0037] like Figure 4 As shown, the MCU control module 3 includes an MCU chip U1, a resistor R17, a resistor R19, a resistor R22, a resistor R33, a Hall U3, a Hall U4, a capacitor C7 and a capacitor C8. The first pin of the MCU chip U1 is connected to the second step-down unit 22 and one end of the capacitor C8 respectively, and the other end of the capacitor C8 is grounded. The second pin of the MCU chip U1, the third pin of the MCU chip U1, the fourth pin of the MCU chip U1 and the fifth pin of the MCU chip U1 are all connected to the half-bridge control module 4, the sixth pin of the MCU chip U1 is connected to the surge suppression module 1, and the seventh pin of the MCU chip U1 is connected to the motor drive module 5. The eighth pin of the MCU chip U1 is respectively connected to one end of the capacitor C7 and one end of the resistor R17, the ninth pin of the MCU chip U1 is connected to the PWM input port, the tenth pin of the MCU chip U1 and the other end of the capacitor C7 are grounded together, the other end of the resistor R17 is respectively connected to the third end of the Hall U3, the third end of the Hall U4 and one end of the resistor R19, the other end of the resistor R19 is respectively connected to the first end of the Hall U3, the first end of the Hall U4 and one end of the resistor R22, the second end of the Hall U3 and the second end of the Hall U4 are grounded together, and the other end of the resistor R22 is connected to the second step-down unit 22 through the resistor R33.

[0038] The half-bridge control module 4 is electrically connected to the motor driving module 5 . The half-bridge control module 4 is used to receive a driving signal sent by the MCU control module 3 and drive the motor driving module 5 according to the driving signal.

[0039] like Figure 5 As shown, the half-bridge control module 4 includes a half-bridge driving chip U2, a half-bridge driving chip U5, a resistor R13, a resistor R15, a resistor R18, a resistor R23, a resistor R25, a resistor R28, a capacitor C5, a capacitor C6, a capacitor C10, a capacitor C11, a diode D7 and a diode D8.

[0040] The first pin of the half-bridge driver chip U2 is respectively connected to the first buck unit 21, one end of the capacitor C5 and one end of the resistor R13, the other end of the capacitor C5 is grounded, one end of the resistor R15 is connected to the MCU control module 3, the other end of the resistor R15 is connected to the second pin of the half-bridge driver chip U2, the third pin of the half-bridge driver chip U2 is connected to one end of the resistor R18, the other end of the resistor R18 is connected to the MCU control module 3, the fourth pin of the half-bridge driver chip U2 is grounded, the other end of the resistor R13 is connected to the positive electrode of the diode D7, the fifth pin of the half-bridge driver chip U2 is connected to the motor driver module 5, the sixth pin of the half-bridge driver chip U2 is respectively connected to one end of the capacitor C6, the other end of the resistor R11, the source of the MOS tube Q1, the drain of the MOS tube Q2 and the terminal L1, the seventh pin of the half-bridge driver chip U2 is connected to the motor driver module 5, and the eighth pin of the half-bridge driver chip U2 is respectively connected to the other end of the capacitor C6 and the negative electrode of the diode D7.

[0041] The first pin of the half-bridge driver chip U5 is respectively connected to the first buck unit 21, one end of the capacitor C10 and one end of the resistor R23, the other end of the capacitor C10 is grounded, one end of the resistor R25 is connected to the MCU control module 3, the other end of the resistor R25 is connected to the second pin of the half-bridge driver chip U5, the third pin of the half-bridge driver chip U5 is connected to one end of the resistor R28, the other end of the resistor R28 is connected to the MCU control module 3, the fourth pin of the half-bridge driver chip U5 is grounded, the other end of the resistor R23 is connected to the positive electrode of the diode D8, the fifth pin of the half-bridge driver chip U5 is connected to the motor driver module 5, the sixth pin of the half-bridge driver chip U5 is respectively connected to one end of the capacitor C11, the other end of the resistor R20, the source of the MOS tube Q3, the drain of the MOS tube Q4 and the terminal L2, the seventh pin of the half-bridge driver chip U5 is connected to the motor driver module 5, and the eighth pin of the half-bridge driver chip U5 is respectively connected to the other end of the capacitor C11 and the negative electrode of the diode D8.

[0042] like Figure 6As shown, the motor drive module 5 includes a resistor R7, a resistor R11, a resistor R12, a resistor R14, a resistor R16, a resistor R20, a resistor R21, a resistor R24, a resistor R26, a resistor R27, a MOS transistor Q1, a MOS transistor Q2, a MOS transistor Q3, a MOS transistor Q4, a terminal L1, a terminal L2 and a capacitor C12, one end of the resistor R7 is connected to the half-bridge control module 4, the other end of the resistor R7 is respectively connected to one end of the resistor R11 and the gate of the MOS transistor Q1, the other end of the resistor R11 is respectively connected to the source of the MOS transistor Q1, the drain of the MOS transistor Q2 and the terminal L1, the drain of the MOS transistor Q1 is respectively connected to the drain of the surge suppression module 1 and the drain of the MOS transistor Q3, one end of the resistor R12 is connected to the half-bridge control module 4, the other end of the resistor R12 is respectively connected to the MOS transistor Q2 The gate of the MOS tube Q3 is connected to one end of the resistor R14, the other end of the resistor R14 is respectively connected to the source of the MOS tube Q2, the source of the MOS tube Q4, the other end of the resistor R24, one end of the resistor R26 and one end of the resistor R27, one end of the resistor R16 is connected to the half-bridge control module 4, the other end of the resistor R16 is connected to one end of the resistor R20 and the gate of the MOS tube Q3, the other end of the resistor R20 is respectively connected to the source of the MOS tube Q3, the drain of the MOS tube Q4 and the terminal L2, one end of the resistor R21 is connected to the half-bridge control module 4, the other end of the resistor R21 is respectively connected to one end of the resistor R24 ​​and the gate of the MOS tube Q4, the other end of the resistor R27 is grounded, the other end of the resistor R26 is respectively connected to one end of the capacitor C12 and the MCU control module 3, and the other end of the capacitor C12 is grounded.

[0043] In this embodiment, 220V AC power is input from two ports, AC+ and AC-, an NTC resistor R32 is connected in series after the AC+ port, and a rectifier bridge is formed by four diodes D1, D2, D4 and D5 to rectify the 220V AC power into 310V DC power. The drain of the MOS tube Q5 in the surge suppression module 1 is connected to the negative electrode of the electrolytic capacitor EC1 and the source is grounded. The positive electrode of the electrolytic capacitor EC1 is connected in series with resistors R35 and R36, so that the voltage is divided to the gate of the MOS tube Q5. At the same time, the rectifier and filter unit 11 outputs a 310V DC voltage, which is converted into a 12V DC voltage through the first step-down unit 21, and after passing through the resistor R6 and the 5.1V Zener diode DZ1 in the second step-down unit 22, the 12V DC voltage is converted into a 5V DC voltage to power the MCU control module 3. Since the voltage across the capacitor cannot change suddenly, the gate voltage across the capacitor C14 and the MOS tube Q5 will slowly increase, making the MOS tube Q5 conduct. Due to the effect of the diode D12, the voltage across the capacitor C14 will eventually be clamped at 12V, and the MOS tube Q5 will eventually work in the saturation region. At the same time, the 310V DC voltage slowly charges the electrolytic capacitor EC1. When the power is off, the resistors R37 and R5 can quickly discharge the voltage across the capacitor C14 and the electrolytic capacitor EC2, which can effectively reduce the surge current. The half-bridge driver chip U2, the half-bridge driver chip U5 and the MOS tube Q1, MOS tube Q2, MOS tube Q3, MOS tube Q4 and the surrounding resistors, capacitors and diodes are electrically connected to form a motor drive circuit, and the drive signal of the motor drive circuit is output by the terminal L1 and the terminal L2. Hall U3, Hall U4 and the surrounding resistors and capacitors form a Hall detection circuit, and the diode D11, the resistors R8, R9, R10 and the capacitor C3 form a voltage detection circuit.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A motor control circuit with low inrush current, characterized in that: It comprises a surge suppression module (1), a voltage conversion module (2), an MCU control module (3), a half-bridge control module (4) and a motor drive module (5), wherein: The surge suppression module (1) is electrically connected to the voltage conversion module (2) and the MCU control module (3) respectively, and comprises a rectifier filter unit (11) and a MOS tube soft switch unit (12). The rectifier filter unit (11) is electrically connected to the MOS tube soft switch unit (12) and the MCU control module (3) respectively, and the rectifier filter unit (11) is used to convert an alternating current voltage into a direct current voltage. The MOS tube soft switch unit (12) is electrically connected to the voltage conversion module (2), and the MOS tube soft switch unit (12) is used to suppress a surge current in the motor control circuit. The voltage conversion module (2) is electrically connected to the MCU control module (3) and the half-bridge control module (4) respectively, and the voltage conversion module (2) is used to clamp the gate voltage of the MOS tube in the surge suppression module (1) at 12V, and to supply power to the MCU control module (3) and the half-bridge control module (4) respectively; The MCU control module (3) is electrically connected to the half-bridge control module (4) and the motor drive module (5) respectively, and the MCU control module (3) is used to send a drive signal to the half-bridge control module (4); The half-bridge control module (4) is electrically connected to the motor drive module (5), and the half-bridge control module (4) is used to receive a drive signal sent by the MCU control module (3) and drive the motor drive module (5) according to the drive signal.

2. The low inrush current motor control circuit according to claim 1, characterized in that: The rectifying and filtering unit (11) comprises a thermistor R32, a resistor R2, a resistor R3, a resistor R8, a resistor R9, a resistor R10, a resistor R34, a capacitor CX1, a capacitor C2, a capacitor C3, an electrolytic capacitor EC1, a diode D1, a diode D2, a diode D4, a diode D5 and a diode D11, one end of the thermistor R32 is connected to the N end of the mains, the other end of the thermistor R32 is respectively connected to one end of the resistor R2, one end of the resistor R3, one end of the capacitor CX1 and the common end of the diode D2 and the diode D3, the other end of the resistor R2 is respectively connected to the L end of the mains, the positive electrode of the diode D11, the other end of the resistor R3, the other end of the capacitor CX1 and the common end of the diode D4 and the diode D5, the diode D1 and the The common end of the diode D4, one end of the resistor R34 and the MOS tube soft switch unit (12) are commonly grounded; the common end of the diode D2 and the diode D5 are respectively connected to one end of the capacitor C2, one end of the electrolytic capacitor EC1 and the MOS tube soft switch unit (12); the other end of the capacitor C2 is respectively connected to the other end of the electrolytic capacitor EC1, the other end of the resistor R34 and the MOS tube soft switch unit (12); the cathode of the diode D11 is connected to one end of the resistor R8; the other end of the resistor R8 is connected to one end of the resistor R9; the other end of the resistor R9 and the first common end of the resistor R10 and the capacitor C3 are all connected to the MCU control module (3); the second common end of the resistor R10 and the capacitor C3 is grounded.

3. The low inrush current motor control circuit according to claim 1, characterized in that: The MOS tube soft switch unit (12) comprises a MOS tube Q5, a capacitor C14, a resistor R35, a resistor R36, a resistor R37 and a diode D12; the drain of the MOS tube Q5 is connected to the rectifying and filtering unit (11); the source of the MOS tube Q5 is respectively connected to the rectifying and filtering unit (11), one end of the capacitor C14 and one end of the resistor R37; the gate of the MOS tube Q5 is respectively connected to the other end of the capacitor C14, the other end of the resistor R37, one end of the resistor R36 and the positive electrode of the diode D12; the other end of the resistor R36 is connected to the rectifying and filtering unit (11) via the resistor R35; and the negative electrode of the diode D12 is connected to the voltage conversion module (2).

4. The low inrush current motor control circuit according to claim 1, characterized in that: The voltage conversion module (2) comprises a first buck unit (21) and a second buck unit (22); the first buck unit (21) is electrically connected to the second buck unit (22), the surge suppression module (1) and the half-bridge control module (4), respectively; and the second buck unit (22) is electrically connected to the MCU control module (3).

5. The low inrush current motor control circuit according to claim 4, characterized in that: The first step-down unit (21) comprises a power chip U6, a resistor R4, a resistor R5, a capacitor C1, an electrolytic capacitor EC2, an inductor LS1, a diode D3 and a diode D6. The first pin of the power chip U6 is respectively connected to one end of the resistor R4, the cathode of the diode D6, one end of the inductor LS1 and one end of the capacitor C1. The second pin of the power chip U6 is respectively connected to the third pin of the power chip U6, the other end of the capacitor C1 and the cathode of the diode D3. The fourth pin of the power chip U6 is connected to the surge suppression module (1). The fifth pin of the power chip U6 is connected to the other end of the resistor R4. The anode of the diode D3 is respectively connected to the other end of the inductor LS1, one end of the resistor R5, one end of the electrolytic capacitor EC2 and the second step-down unit (22). The anode of the diode D6, the other end of the resistor R5 and the other end of the electrolytic capacitor EC2 are grounded together.

6. The low inrush current motor control circuit according to claim 4, characterized in that: The second step-down unit (22) comprises a resistor R6, a voltage-stabilizing diode DZ1 and a capacitor C4, one end of the resistor R6 is connected to the first step-down unit (21), the other end of the resistor R6 is connected to the positive electrode of the voltage-stabilizing diode DZ1, one end of the capacitor C4 and the MCU control module (3), and the other end of the capacitor C4 and the positive electrode of the voltage-stabilizing diode DZ1 are grounded together.

7. The low inrush current motor control circuit according to claim 6, characterized in that: The MCU control module (3) comprises an MCU chip U1, a resistor R17, a resistor R19, a resistor R22, a resistor R33, a Hall U3, a Hall U4, a capacitor C7 and a capacitor C8; a first pin of the MCU chip U1 is respectively connected to the second step-down unit (22) and one end of the capacitor C8; the other end of the capacitor C8 is grounded; a second pin of the MCU chip U1, a third pin of the MCU chip U1, a fourth pin of the MCU chip U1 and a fifth pin of the MCU chip U1 are all connected to the half-bridge control module (4); a sixth pin of the MCU chip U1 is connected to the surge suppression module (1); and a seventh pin of the MCU chip U1 is connected to the motor drive module (5). The eighth pin of the MCU chip U1 is respectively connected to one end of the capacitor C7 and one end of the resistor R17, the ninth pin of the MCU chip U1 is connected to the PWM input port, the tenth pin of the MCU chip U1 and the other end of the capacitor C7 are grounded together, the other end of the resistor R17 is respectively connected to the third end of the Hall U3, the third end of the Hall U4 and one end of the resistor R19, the other end of the resistor R19 is respectively connected to the first end of the Hall U3, the first end of the Hall U4 and one end of the resistor R22, the second end of the Hall U3 and the second end of the Hall U4 are grounded together, and the other end of the resistor R22 is connected to the second step-down unit (22) through the resistor R33.

8. The low inrush current motor control circuit according to claim 1, characterized in that: The motor drive module (5) comprises a resistor R7, a resistor R11, a resistor R12, a resistor R14, a resistor R16, a resistor R20, a resistor R21, a resistor R24, a resistor R26, a resistor R27, a MOS transistor Q1, a MOS transistor Q2, a MOS transistor Q3, a MOS transistor Q4, a terminal L1, a terminal L2 and a capacitor C12; one end of the resistor R7 is connected to the half-bridge control module (4); the other end of the resistor R7 is respectively connected to one end of the resistor R11 and the gate of the MOS transistor Q1; the other end of the resistor R11 is respectively connected to the source of the MOS transistor Q1, the drain of the MOS transistor Q2 and the terminal L1; the drain of the MOS transistor Q1 is respectively connected to the surge suppression module (1) and the drain of the MOS transistor Q3; one end of the resistor R12 is connected to the half-bridge control module (4); the other end of the resistor R12 is respectively connected to the gate of the MOS transistor Q2 and the gate of the resistor R1 4, the other end of the resistor R14 is respectively connected to the source of the MOS transistor Q2, the source of the MOS transistor Q4, the other end of the resistor R24, one end of the resistor R26 and one end of the resistor R27, one end of the resistor R16 is connected to the half-bridge control module (4), the other end of the resistor R16 is respectively connected to one end of the resistor R20 and the gate of the MOS transistor Q3, the other end of the resistor R20 is respectively connected to the source of the MOS transistor Q3, the drain of the MOS transistor Q4 and the terminal L2, one end of the resistor R21 is connected to the half-bridge control module (4), the other end of the resistor R21 is respectively connected to one end of the resistor R24 ​​and the gate of the MOS transistor Q4, the other end of the resistor R27 is grounded, the other end of the resistor R26 is respectively connected to one end of the capacitor C12 and the MCU control module (3), and the other end of the capacitor C12 is grounded.

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