Relay control motor driving circuit

Abstract

The utility model provides a relay control motor drive circuit comprising a power supply circuit; according to the H-bridge motor driving circuit, two ends of a motor are electrically connected with a motor power supply through an output end of a relay respectively, two ends of the motor are further electrically connected with one end of a first resistor through the output end of the relay respectively, and the other end of the first resistor is grounded; the first coil end of each relay is electrically connected with the output end of the power supply circuit, the second coil end of each relay is electrically connected with the output end of an electronic switch, and the input end of each electronic switch is grounded; the input end of the current acquisition circuit is electrically connected with the output end of one relay; and the control end of each electronic switch and the output end of the current acquisition circuit are electrically connected with the main control chip. According to the utility model, the four relays and the four electronic switches form an H-bridge motor driving circuit, so that the H-bridge motor driving circuit can bear switch control under higher voltage, and forward rotation and reverse rotation of the motor under high voltage can be conveniently controlled.

Description

Technical Field

[0001] The utility model relates to the technical field of motor driving, in particular to a relay-controlled motor driving circuit. Background Art

[0002] With the development of science and technology, the emergence of motors can greatly save manpower. In actual use, the motor may need to have both forward and reverse rotation to achieve driving in different directions, which makes the voltage connected to both ends of the motor also have two different states.

[0003] In traditional circuits, in order to achieve this function, an H-bridge drive circuit is designed: the two ends of the motor are electrically connected to the positive pole through a MOS tube, and the two ends of the motor are also electrically connected to the negative pole through a MOS tube, so as to facilitate the adjustment of the voltage at both ends of the motor.

[0004] However, this traditional motor drive circuit can only drive low-power motors. For high-power and high-voltage motors, if this circuit is still used, the MOS tube will burn out due to excessive current after conduction, and the motor cannot be driven forward or reverse. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide a relay-controlled motor driving circuit to solve the problem that high-power and high-voltage cannot drive the motor forward and reverse through an H-bridge driving circuit in the prior art.

[0006] The technical solution adopted by the utility model to solve the above problems is: a relay-controlled motor drive circuit, comprising:

[0007] A power supply circuit, wherein an input end of the power supply circuit is electrically connected to a motor power supply;

[0008] An H-bridge motor driving circuit, used for driving a motor to rotate forward and reverse, comprises four relays and four electronic switches, wherein two ends of the motor are electrically connected to a motor power supply through an output end of a relay, and two ends of the motor are electrically connected to one end of a first resistor through an output end of a relay, and the other end of the first resistor is grounded; a first coil end of each relay is electrically connected to an output end of a power supply circuit, a second coil end of each relay is electrically connected to an output end of an electronic switch, and an input end of each electronic switch is grounded;

[0009] A current collection circuit, wherein an input end of the current collection circuit is electrically connected to an output end of one of the relays;

[0010] The main control chip U3 has a power supply terminal electrically connected to the output terminal of the power supply circuit, and the control terminal of each electronic switch and the output terminal of the current acquisition circuit are electrically connected to the main control chip U3; the main control chip U3 controls the electronic switch to be closed or opened according to the current value collected by the current acquisition circuit.

[0011] Compared with the prior art, the advantages of the utility model are: four relays and four electronic switches constitute an H-bridge motor drive circuit, which can withstand switch control under higher voltage and facilitate the control of motor forward rotation and motor reverse rotation under high voltage; and the main control chip U3 collects the current value between the motor and the first resistor through the current acquisition circuit, which is convenient for monitoring whether the motor is overloaded, and then controls the closing and opening of the electronic switch to ensure that the motor can work normally.

[0012] Preferably, the first end of the motor is electrically connected to the positive electrode of the motor power supply through the output end of the first relay K1, and the second end of the motor is electrically connected to the positive electrode of the motor power supply through the output end of the third relay K3; the first end of the motor is also electrically connected to the first end of the resistor R22 through the output end of the second relay K2, and the second end of the motor is also electrically connected to the first end of the resistor R22 through the output end of the fourth relay K4, and the second end of the resistor R22 is grounded.

[0013] The technical effect achieved by adopting this technical solution is as follows: the H-bridge drives the motor through four relays, so that the motor can rotate forward and reverse; at the same time, after the motor is connected to the power supply, it is also grounded through the resistor R22, which facilitates the current collection circuit to collect the current between the motor and the resistor R22.

[0014] Preferably, the first coil end of each relay is electrically connected to the cathode of a diode, and the anode of the diode is electrically connected to the second coil end of the relay.

[0015] The technical effect achieved by adopting this technical solution is that diodes are connected in parallel at both ends of the relay coil, which can release the energy stored in the relay coil when it is turned on by the electronic switch, preventing the induced voltage from being too high and breaking down the electronic switch connected to it.

[0016] Preferably, the electronic switch is a triode, the base of the triode is electrically connected to the main control chip U3 through a second resistor, the base of the triode is electrically connected to the emitter of the triode through a third resistor, the emitter of the triode is grounded, and the collector of the triode is electrically connected to the second coil end of the relay.

[0017] The technical effect achieved by adopting this technical solution is that the voltage required at the coil end of the relay is relatively small, and the on and off functions can be realized by using a triode as an electronic switch.

[0018] Preferably, the current acquisition circuit includes an operational amplifier U6; a power pin V+ of the operational amplifier U6 is electrically connected to the output end of the power supply circuit, and a ground pin GND and a reference voltage input pin REF of the operational amplifier U6 are both grounded; a non-inverting input pin IN+ of the operational amplifier U6 is electrically connected to a first end of a resistor R22 through a resistor R19, an inverting input pin IN- of the operational amplifier U6 is grounded through a resistor R20, and a non-inverting input pin IN+ of the operational amplifier U6 is electrically connected to an inverting input pin IN- through a capacitor C13; an output pin OUT of the operational amplifier U6 is connected in series with a resistor R23 and a capacitor C16 to ground, and a connecting end of the resistor R23 and the capacitor C16 is electrically connected to a main control chip U3.

[0019] The technical effect achieved by adopting this technical solution is as follows: the operational amplifier U6 collects the current value between the motor and the resistor R22 through the non-inverting input pin IN+ and the inverting input pin IN-, amplifies it and then inputs it into the main control chip U3, so that the main control chip U3 can identify whether the motor is overloaded and cut it off in time to ensure that the motor is not damaged.

[0020] Preferably, the power supply circuit includes a relay power supply circuit for powering the relay, and a chip power supply circuit for powering the main control chip U3 and the current acquisition circuit; the input end of the relay power supply circuit is electrically connected to the motor power supply, the output end of the relay power supply circuit is electrically connected to the first coil end of the relay, the input end of the chip power supply circuit is electrically connected to the output end of the relay power supply circuit, and the output end of the chip power supply circuit is electrically connected to the power supply end of the main control chip U3 and the power supply end of the current acquisition circuit.

[0021] Preferably, the relay power supply circuit includes a DC conversion chip U5; a voltage input pin VIN of the DC conversion chip U5 is electrically connected to the cathode of the diode D8, a positive electrode of the diode D8 is electrically connected to the cathode of the motor power supply, a resistor R10 and a resistor R14 are connected in series with the cathode of the motor power supply, a capacitor C12 is connected in parallel at both ends of the resistor R14, a voltage input pin VIN of the DC conversion chip U5 is electrically connected to the cathode of the diode D2, a positive electrode of the diode D2 is grounded, and a voltage input pin VIN of the DC conversion chip U5 is grounded through capacitors C11 and EC3 respectively; a working voltage pin VDD of the DC conversion chip U5 is electrically connected to a voltage input pin VIN of the DC conversion chip U5 through a resistor R8, and a working voltage pin VDD of the DC conversion chip U5 is grounded through a capacitor C10; a voltage output pin VIN of the DC conversion chip U5 is electrically connected to a ... The CS pin is connected in series with the resistor R7 and the inductor L6, and is electrically connected to the positive electrode of the capacitor EC1, one end of the resistor R9, the positive electrode of the diode D3, and the first coil end of the relay respectively. The resistor R28 is connected in parallel at both ends of the resistor R7. The connecting end of the resistor R7 and the inductor L6 is electrically connected to the common ground pin of the DC conversion chip U5. The negative electrode of the capacitor EC1 and the other end of the resistor R9 are both grounded. The negative electrode of the diode D3 is electrically connected to the working voltage pin VDD of the DC conversion chip U5 through the resistor R11; the common ground pin VSS of the DC conversion chip U5 is grounded, and the common ground pin VSS of the DC conversion chip U5 is electrically connected to the negative electrode of the diode D1, and the positive electrode of the diode D1 is grounded; the feedback voltage pin VFB of the DC conversion chip U5 is grounded through the resistor R12, and the positive electrode of the diode D3 is electrically connected to the feedback voltage pin VFB of the DC conversion chip U5 through the resistor R13.

[0022] The technical effect achieved by adopting this technical solution is: the voltage of the motor power supply is converted into the power required by the relay coil end through the DC conversion chip U5, ensuring that the relay can work normally and stably.

[0023] Preferably, the chip power supply circuit includes a voltage stabilizing chip U4, which is HT7533. The input end of the voltage stabilizing chip U4 is electrically connected to the output end of the relay power supply circuit, and the input end of the voltage stabilizing chip U4 is grounded through a capacitor C9. The output end of the voltage stabilizing chip U4 is electrically connected to the power supply end of the main control chip U3, and the output end of the voltage stabilizing chip U4 is grounded through a capacitor EC2.

[0024] The technical effect achieved by adopting this technical solution is: the voltage input to the main control chip U3 is ensured to be stable through the voltage stabilizing chip U4, so that the main control chip U3 can work stably.

[0025] Preferably, it also includes a temperature measuring circuit for measuring the working temperature of the motor; the temperature measuring circuit includes a thermocouple P1 and a temperature control chip U2 for measuring the motor, the thermocouple P1 is electrically connected to the temperature control chip U2, and the temperature control chip U2 is electrically connected to the main control chip U3; the main control chip U3 controls the electronic switch to close or open according to the temperature value collected by the temperature control chip U2.

[0026] The technical effect achieved by adopting this technical solution is as follows: the temperature inside or outside the motor is measured by thermocouple P1, and the temperature information is transmitted to the main control chip U3 through the temperature control chip U2. When the temperature is too high, the main control chip U3 can cut off the operation of the motor, which has a temperature protection function.

[0027] Preferably, it also includes a wired control circuit and / or a wireless control circuit for adjusting the motor speed; the wired control circuit includes a plurality of buttons and a plurality of transistors Q1 paired with the buttons, the output end of the button is electrically connected to the collector of the transistor Q1, the collector of the transistor Q1 is electrically connected to the output end of the power supply circuit through a resistor R1, the emitter of the transistor Q1 is grounded, the base of the transistor Q1 is electrically connected to the emitter of the transistor Q1 through a resistor R5, and the base of the transistor Q1 is electrically connected to the main control chip U3 through a resistor R3; the input end of the wireless control circuit is electrically connected to the antenna, and the output end of the wireless control circuit is electrically connected to the main control chip U3.

[0028] The technical effect achieved by adopting this technical solution is: through wired control circuits and wireless control circuits, the speed of the motor can be adjusted in different ways. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a system block diagram of a relay-controlled motor drive circuit of the utility model;

[0030] Figure 2 This is a circuit diagram of an H-bridge motor drive circuit and a current acquisition circuit in a relay-controlled motor drive circuit of the utility model;

[0031] Figure 3 This is a circuit diagram of a power supply circuit in a relay-controlled motor drive circuit of the utility model;

[0032] Figure 4 This is a circuit diagram of a main control chip in a relay-controlled motor drive circuit of the utility model;

[0033] Figure 5 The utility model discloses a circuit diagram of a wireless control circuit in a relay-controlled motor drive circuit. DETAILED DESCRIPTION

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0035] like Figures 1 to 5 As shown, this embodiment relates to a relay-controlled motor drive circuit, comprising:

[0036] A power circuit, wherein an input end of the power circuit is electrically connected to a motor power supply;

[0037] An H-bridge motor driving circuit, used for driving a motor to rotate forward and reverse, comprises four relays and four electronic switches, wherein two ends of the motor are electrically connected to a motor power supply through an output end of a relay, and two ends of the motor are electrically connected to one end of a first resistor through an output end of a relay, and the other end of the first resistor is grounded; a first coil end of each relay is electrically connected to an output end of a power supply circuit, a second coil end of each relay is electrically connected to an output end of an electronic switch, and an input end of each electronic switch is grounded;

[0038] A current collection circuit, wherein an input end of the current collection circuit is electrically connected to an output end of one of the relays;

[0039] The main control chip U3 has a power supply terminal electrically connected to the output terminal of the power supply circuit, and the control terminal of each electronic switch and the output terminal of the current acquisition circuit are electrically connected to the main control chip U3; the main control chip U3 controls the electronic switch to close or open according to the current value collected by the current acquisition circuit.

[0040] Four relays and four electronic switches constitute an H-bridge motor drive circuit, which can withstand switch control under higher voltage and facilitate the control of motor forward rotation and motor reverse rotation under high voltage; and the main control chip U3 collects the current value between the motor and the first resistor through the current acquisition circuit, which is convenient for monitoring whether the motor is overloaded, and then controls the closing and opening of the electronic switch to ensure that the motor can work normally.

[0041] See also Figure 2 As shown, in this embodiment, the first end of the motor is electrically connected to the positive electrode of the motor power supply through the output end of the first relay K1, and the second end of the motor is electrically connected to the positive electrode of the motor power supply through the output end of the third relay K3; the first end of the motor is also electrically connected to the first end of the resistor R22 through the output end of the second relay K2, and the second end of the motor is also electrically connected to the first end of the resistor R22 through the output end of the fourth relay K4, and the second end of the resistor R22 is grounded.

[0042] The H-bridge drives the motor through four relays, so that the motor can rotate forward and reverse. At the same time, after the motor is connected to the power supply, it is also grounded through the resistor R22, which makes it convenient for the current collection circuit to collect the current between the motor and the resistor R22.

[0043] In the actual circuit, resistor R21 is also connected in parallel at both ends of resistor R22. The purpose of adjusting the resistance value of resistor R22 can be achieved by connecting resistors in parallel, so that the current collection circuit can collect current conveniently.

[0044] The first coil end of each relay is electrically connected to the cathode of a diode, and the anode of the diode is electrically connected to the second coil end of the relay.

[0045] A diode is connected in parallel at both ends of the relay coil. When it is turned on by the electronic switch, it can release the energy stored in the relay coil to prevent the induced voltage from being too high and breaking down the electronic switch connected to it.

[0046] In this embodiment, the electronic switch is a triode, the base of the triode is electrically connected to the main control chip U3 through the second resistor, the base of the triode is electrically connected to the emitter of the triode through the third resistor, the emitter of the triode is grounded, and the collector of the triode is electrically connected to the second coil end of the relay.

[0047] The voltage required at the coil end of the relay is relatively small, and the on and off functions can be achieved by using a transistor as an electronic switch.

[0048] Of course, in actual circuits, electronic switches can also be MOS tubes, photocouplers, relays and other components with switching properties.

[0049] See also Figure 2 As shown, the current acquisition circuit includes an operational amplifier U6; the power pin V+ of the operational amplifier U6 is electrically connected to the output end of the power supply circuit, and the ground pin GND and the reference voltage input pin REF of the operational amplifier U6 are both grounded; the non-inverting input pin IN+ of the operational amplifier U6 is electrically connected to the first end of the resistor R22 through the resistor R19, the inverting input pin IN- of the operational amplifier U6 is grounded through the resistor R20, and the non-inverting input pin IN+ of the operational amplifier U6 is electrically connected to the inverting input pin IN- through the capacitor C13; the output pin OUT of the operational amplifier U6 is connected in series with the resistor R23 and the capacitor C16 to ground, and the connecting end of the resistor R23 and the capacitor C16 is electrically connected to the main control chip U3.

[0050] The operational amplifier U6 collects the current value between the motor and the resistor R22 through the non-inverting input pin IN+ and the inverting input pin IN-, amplifies it and then inputs it to the main control chip U3, so that the main control chip U3 can identify whether the motor is overloaded and cut it off in time to ensure that the motor is not damaged. The operational amplifier U6 is an existing technology and only needs to be able to amplify the signal.

[0051] See also Figure 3As shown, in this embodiment, the power supply circuit includes a relay power supply circuit for supplying power to the relay, and a chip power supply circuit for supplying power to the main control chip U3 and the current acquisition circuit.

[0052] The input end of the relay power supply circuit is electrically connected to the motor power supply, the output end of the relay power supply circuit is electrically connected to the first coil end of the relay, the input end of the chip power supply circuit is electrically connected to the output end of the relay power supply circuit, and the output end of the chip power supply circuit is electrically connected to the power supply end of the main control chip U3 and the power supply end of the current acquisition circuit.

[0053] In this embodiment, the motor power supply is 72-75V DC; the voltage required by the relay coil is 12V, that is, the voltage at the first coil end of the relay is 12V; and the voltage required by the power supply end of the main control chip U3 is 3.3V.

[0054] Among them, the relay power supply circuit includes a DC conversion chip U5.

[0055] The voltage input pin VIN of the DC conversion chip U5 is electrically connected to the cathode of the diode D8, the anode of the diode D8 is electrically connected to the anode of the motor power supply, the anode of the diode D8 is connected in series with resistor R10 and resistor R14 and is electrically connected to the cathode of the motor power supply, a capacitor C12 is connected in parallel across the resistor R14, the voltage input pin VIN of the DC conversion chip U5 is electrically connected to the cathode of the diode D2, the anode of the diode D2 is grounded, and the voltage input pin VIN of the DC conversion chip U5 is grounded through capacitor C11 and capacitor EC3 respectively.

[0056] The working voltage pin VDD of the DC conversion chip U5 is electrically connected to the voltage input pin VIN of the DC conversion chip U5 through the resistor R8, and the working voltage pin VDD of the DC conversion chip U5 is grounded through the capacitor C10.

[0057] The voltage output pin CS of the DC conversion chip U5 is connected in series with resistor R7 and inductor L6, and is electrically connected to the positive electrode of capacitor EC1, one end of resistor R9, the positive electrode of diode D3, and the first coil end of the relay respectively. Resistor R28 is connected in parallel at both ends of resistor R7. The connecting end of resistor R7 and inductor L6 is electrically connected to the common ground pin of the DC conversion chip U5. The negative electrode of capacitor EC1 and the other end of resistor R9 are both grounded. The negative electrode of diode D3 is electrically connected to the working voltage pin VDD of the DC conversion chip U5 through resistor R11.

[0058] The common ground pin VSS of the DC conversion chip U5 is grounded, and the common ground pin VSS of the DC conversion chip U5 is electrically connected to the cathode of the diode D1 , and the anode of the diode D1 is grounded.

[0059] The feedback voltage pin VFB of the DC conversion chip U5 is grounded through the resistor R12 , and the anode of the diode D3 is electrically connected to the feedback voltage pin VFB of the DC conversion chip U5 through the resistor R13 .

[0060] The DC conversion chip U5 converts the voltage of the motor power supply into the power required by the relay coil end to ensure that the relay can work normally and stably. The DC conversion chip U5 is an existing technology and only needs to be able to convert the 72-75V DC voltage into a 12V DC voltage.

[0061] Among them, the chip power supply circuit includes a voltage regulator chip U4, which is HT7533. The input end of the voltage regulator chip U4 is electrically connected to the output end of the relay power supply circuit, and the input end of the voltage regulator chip U4 is grounded through capacitor C9. The output end of the voltage regulator chip U4 is electrically connected to the power supply end of the main control chip U3, and the output end of the voltage regulator chip U4 is grounded through capacitor EC2.

[0062] The voltage stabilizer chip U4 ensures that the voltage input to the main control chip U3 is stable, so that the main control chip U3 can work stably.

[0063] See also Figure 4 As shown, in this embodiment, a relay-controlled motor drive circuit also includes a temperature measurement circuit for measuring the working temperature of the motor.

[0064] The temperature measurement circuit includes a thermocouple P1 and a temperature control chip U2 for measuring the motor. The thermocouple P1 is electrically connected to the temperature control chip U2, and the temperature control chip U2 is electrically connected to the main control chip U3. The main control chip U3 controls the electronic switch to close or open according to the temperature value collected by the temperature control chip U2.

[0065] The temperature inside or outside the motor is measured by the thermocouple P1, and the temperature information is transmitted to the main control chip U3 through the temperature control chip U2. When the temperature is too high, the main control chip U3 can cut off the motor operation, which has a temperature protection function. The main control chip U3 measures the motor voltage by voltage division, thereby realizing the low voltage protection function.

[0066] See also Figure 4 and Figure 5 As shown, in this embodiment, a relay-controlled motor drive circuit also includes a wired control circuit and / or a wireless control circuit for adjusting the motor speed.

[0067] The wired control circuit includes several buttons and several transistors Q1 paired with the buttons. The output end of the button is electrically connected to the collector of the transistor Q1, the collector of the transistor Q1 is electrically connected to the output end of the power supply circuit through the resistor R1, the emitter of the transistor Q1 is grounded, the base of the transistor Q1 is electrically connected to the emitter of the transistor Q1 through the resistor R5, and the base of the transistor Q1 is electrically connected to the main control chip U3 through the resistor R3; the input end of the wireless control circuit is electrically connected to the antenna, and the output end of the wireless control circuit is electrically connected to the main control chip U3.

[0068] Through the wired control circuit and the wireless control circuit, the speed of the motor can be adjusted in different ways. At the same time, the wired control circuit and the wireless control circuit can also be interlocked to prevent misoperation.

[0069] Among them, the wireless control circuit is an existing technology, and the wireless control adopts FSK modulation to effectively avoid motor interference, and the frequency is 433.92MHz.

[0070] The beneficial effects of the utility model are as follows: four relays and four electronic switches constitute an H-bridge motor drive circuit, which can withstand switch control under higher voltage and facilitate the control of motor forward rotation and motor reverse rotation under high voltage; and the main control chip U3 collects the current value between the motor and the first resistor through the current acquisition circuit, which is convenient for monitoring whether the motor is overloaded, and then controls the closing and opening of the electronic switch to ensure that the motor can work normally.

[0071] The above description shows and describes several preferred embodiments of the utility model, but as mentioned above, it should be understood that the utility model is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the utility model concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the utility model, and should be within the scope of protection of the claims attached to the utility model.

[0072] Although the disclosure is as above, the protection scope of the disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the disclosure, and these changes and modifications will fall within the protection scope of the utility model.

Claims

1. A relay-controlled motor drive circuit, characterized in that: include: A power supply circuit, wherein an input end of the power supply circuit is electrically connected to a motor power supply; An H-bridge motor driving circuit, used for driving a motor to rotate forward and reverse, comprises four relays and four electronic switches, wherein two ends of the motor are electrically connected to a motor power supply through an output end of a relay, and two ends of the motor are electrically connected to one end of a first resistor through an output end of a relay, and the other end of the first resistor is grounded; a first coil end of each relay is electrically connected to an output end of a power supply circuit, a second coil end of each relay is electrically connected to an output end of an electronic switch, and an input end of each electronic switch is grounded; A current collection circuit, wherein an input end of the current collection circuit is electrically connected to an output end of one of the relays; The main control chip U3 has a power supply terminal electrically connected to the output terminal of the power supply circuit, and the control terminal of each electronic switch and the output terminal of the current acquisition circuit are electrically connected to the main control chip U3; the main control chip U3 controls the electronic switch to be closed or opened according to the current value collected by the current acquisition circuit.

2. A relay-controlled motor drive circuit according to claim 1, characterized in that: The first end of the motor is electrically connected to the positive electrode of the motor power supply through the output end of the first relay K1, and the second end of the motor is electrically connected to the positive electrode of the motor power supply through the output end of the third relay K3; The first end of the motor is also electrically connected to the first end of the resistor R22 through the output end of the second relay K2, the second end of the motor is also electrically connected to the first end of the resistor R22 through the output end of the fourth relay K4, and the second end of the resistor R22 is grounded.

3. A relay-controlled motor drive circuit according to claim 2, characterized in that: The first coil end of each relay is electrically connected to the cathode of a diode, and the anode of the diode is electrically connected to the second coil end of the relay.

4. A relay-controlled motor drive circuit according to claim 2, characterized in that: The electronic switch is a triode, the base of the triode is electrically connected to the main control chip U3 through the second resistor, the base of the triode is electrically connected to the emitter of the triode through the third resistor, the emitter of the triode is grounded, and the collector of the triode is electrically connected to the second coil end of the relay.

5. A relay-controlled motor drive circuit according to claim 2, characterized in that: The current collection circuit includes an operational amplifier U6; The power pin V+ of the operational amplifier U6 is electrically connected to the output end of the power circuit, and the ground pin GND and the reference voltage input pin REF of the operational amplifier U6 are both grounded; The non-inverting input pin IN+ of the operational amplifier U6 is electrically connected to the first end of the resistor R22 through the resistor R19, the inverting input pin IN- of the operational amplifier U6 is grounded through the resistor R20, and the non-inverting input pin IN+ of the operational amplifier U6 is electrically connected to the inverting input pin IN- through the capacitor C13; The output pin OUT of the operational amplifier U6 is connected in series with a resistor R23 and a capacitor C16 to be grounded, and the connection end of the resistor R23 and the capacitor C16 is electrically connected to the main control chip U3.

6. A relay-controlled motor drive circuit according to claim 1, characterized in that: The power supply circuit includes a relay power supply circuit for supplying power to the relay, and a chip power supply circuit for supplying power to the main control chip U3 and the current acquisition circuit; The input end of the relay power supply circuit is electrically connected to the motor power supply, the output end of the relay power supply circuit is electrically connected to the first coil end of the relay, the input end of the chip power supply circuit is electrically connected to the output end of the relay power supply circuit, and the output end of the chip power supply circuit is electrically connected to the power supply end of the main control chip U3 and the power supply end of the current acquisition circuit.

7. A relay-controlled motor drive circuit according to claim 6, characterized in that: The relay power supply circuit includes a DC conversion chip U5; The voltage input pin VIN of the DC conversion chip U5 is electrically connected to the cathode of the diode D8, the anode of the diode D8 is electrically connected to the anode of the motor power supply, the anode of the diode D8 is connected in series with the resistor R10 and the resistor R14, which are electrically connected to the cathode of the motor power supply, the resistor R14 is connected in parallel with the capacitor C12, the voltage input pin VIN of the DC conversion chip U5 is electrically connected to the cathode of the diode D2, the anode of the diode D2 is grounded, and the voltage input pin VIN of the DC conversion chip U5 is grounded through the capacitor C11 and the capacitor EC3 respectively; The working voltage pin VDD of the DC conversion chip U5 is electrically connected to the voltage input pin VIN of the DC conversion chip U5 through the resistor R8, and the working voltage pin VDD of the DC conversion chip U5 is grounded through the capacitor C10; The voltage output pin CS of the DC conversion chip U5 is connected in series with a resistor R7 and an inductor L6, and is electrically connected to the positive electrode of the capacitor EC1, one end of the resistor R9, the positive electrode of the diode D3, and the first coil end of the relay respectively. A resistor R28 is connected in parallel at both ends of the resistor R7. The connection end of the resistor R7 and the inductor L6 is electrically connected to the common ground pin of the DC conversion chip U5. The negative electrode of the capacitor EC1 and the other end of the resistor R9 are both grounded. The negative electrode of the diode D3 is electrically connected to the working voltage pin VDD of the DC conversion chip U5 through the resistor R11. The common ground pin VSS of the DC conversion chip U5 is grounded, and the common ground pin VSS of the DC conversion chip U5 is electrically connected to the cathode of the diode D1, and the anode of the diode D1 is grounded; The feedback voltage pin VFB of the DC conversion chip U5 is grounded through a resistor R12, and the anode of the diode D3 is electrically connected to the feedback voltage pin VFB of the DC conversion chip U5 through a resistor R13.

8. A relay-controlled motor drive circuit according to claim 6, characterized in that: The chip power supply circuit includes a voltage stabilizing chip U4, which is HT7533. The input end of the voltage stabilizing chip U4 is electrically connected to the output end of the relay power supply circuit, and the input end of the voltage stabilizing chip U4 is grounded through a capacitor C9. The output end of the voltage stabilizing chip U4 is electrically connected to the power supply end of the main control chip U3, and the output end of the voltage stabilizing chip U4 is grounded through a capacitor EC2.

9. The relay-controlled motor drive circuit according to claim 1, characterized in that: Also included is a temperature measuring circuit for measuring the operating temperature of the motor; The temperature measurement circuit includes a thermocouple P1 and a temperature control chip U2 for measuring the motor. The thermocouple P1 is electrically connected to the temperature control chip U2, and the temperature control chip U2 is electrically connected to the main control chip U3; the main control chip U3 controls the electronic switch to close or open according to the temperature value collected by the temperature control chip U2.

10. The relay-controlled motor drive circuit according to claim 1, characterized in that: Also included is a wired control circuit and / or a wireless control circuit for adjusting the speed of the motor; The wired control circuit includes a plurality of buttons and a plurality of transistors Q1 paired with the buttons, the output end of the button is electrically connected to the collector of the transistor Q1, the collector of the transistor Q1 is electrically connected to the output end of the power supply circuit through a resistor R1, the emitter of the transistor Q1 is grounded, the base of the transistor Q1 is electrically connected to the emitter of the transistor Q1 through a resistor R5, and the base of the transistor Q1 is electrically connected to the main control chip U3 through a resistor R3; The input end of the wireless control circuit is electrically connected to the antenna, and the output end of the wireless control circuit is electrically connected to the main control chip U3.

Images