Forward and reverse rotation module of three-phase motor

Abstract

Disclosed in the present invention is a forward and reverse rotation module of a three-phase motor, comprising a forward rotation circuit and a reverse rotation circuit, wherein the forward rotation circuit and the reverse rotation circuit respectively comprise a delay circuit, an interlocking circuit, a photocoupler driving circuit, and a switching circuit; the input end of the delay circuit is connected to the output end of a three-phase power supply; the interlocking circuit is connected in parallel to the delay circuit; the output end of the delay circuit is connected to the input end of the photocoupler driving circuit; the photocoupler driving circuit comprises a light-emitting diode and two MOSFET transistors connected back-to-back in a common-source configuration; the output end of the photocoupler driving circuit is connected to the input end of the switching circuit for controlling the on-off of the switching circuit; the output end of the switching circuit is connected to the input end of the three-phase motor, thereby forming a forward rotation path or a reverse rotation path. The present invention has good anti-electromagnetic interference performance and good vibration and impact resistance, and when the switching circuit is in an excessive electromagnetic interference state or an excessive vibration and impact state, the switching circuit cannot be turned on by mistake.

Description

A positive and reverse rotation module of a three-phase motor TECHNICAL FIELD

[0001] The present application relates to the field of motor control technology, and particularly to a positive and reverse rotation module of a three-phase motor. BACKGROUND

[0002] The working principle of a three-phase asynchronous motor is based on electromagnetic induction. When a three-phase symmetrical alternating current is input to the stator, a rotating magnetic field is generated between the stator and the rotor. The rotating magnetic field cuts the input of the rotor to generate an induced electromotive force and current in the rotor circuit. The current of the rotor conductor is subjected to force under the action of the rotating magnetic field, so that the rotor rotates. The direction of rotation of the rotor is consistent with the direction of the rotating magnetic field. By changing the direction of the rotating magnetic field, the direction of rotation of the motor can be changed. To change the direction of the rotating magnetic field, only the exchange of any two lines of the three power lines of the three-phase motor is needed. As shown in FIG. 1, when K1´, K2´, and K3´ are turned on, and K4´ and K5´ are turned off, the motor M rotates forward; when K1´, K4´, and K5´ are turned on, and K2´ and K3´ are turned off, the motor M reverses. K1´ is a common phase, which can also be directly connected by a wire without affecting the function. In any case, K2´ and K5´ and K3´ and K4´ cannot be turned on at the same time, otherwise a phase-to-phase short circuit will occur and damage will be caused.

[0003] Generally, electromagnetic relays, contactors, motor forward and reverse rotation modules, etc. can be used to realize the exchange of power lines, thereby realizing the function of forward and reverse rotation of the motor. In addition, as shown in FIG. 2, the existing motor forward and reverse rotation module usually uses a non-contact semiconductor switch (such as a thyristor) to realize the switching function, which is composed of 4 or 5 solid-state relays (each solid-state relay is composed of an optical coupler, a thyristor, and other auxiliary electronic components) and other interlocking delay circuits, etc.

[0004] However, the existing technologies have the following deficiencies:

[0005] 1. The action time of electromagnetic relays and contactors is relatively slow, and the reverse braking function cannot be realized, so the application range is easily limited.

[0006] 2. The output end of the electromagnetic relay and the contactor realizes the switching function by using the contact method, which is easy to produce electric sparks when turning on and off, affecting the use of the circuit.

[0007] 3. The anti-vibration performance of the electromagnetic relay and the contactor is poor, and the overall service life is short, and the reliability is low.

[0008] 4. The anti-electromagnetic interference ability of the ordinary solid-state relay is weak, and when subjected to strong external electromagnetic interference, it is easy to misdirect on, which leads to product damage due to phase-to-phase short circuit.

[0009] 5. Solid-state relays with strong anti-electromagnetic interference ability are too expensive. SUMMARY

[0010] The present application aims to provide a forward and reverse rotation module of a three-phase motor to solve the technical problems mentioned in the background art.

[0011] To achieve the above-mentioned purpose, the solution of the present application is: a forward and reverse rotation module of a three-phase motor, comprising a forward rotation circuit and a reverse rotation circuit, both of which comprise a delay circuit, an interlocking circuit, an opto-coupler driving circuit and a switching circuit; the input end of the delay circuit is connected with the output end of a three-phase power supply, the interlocking circuit is connected in parallel with the delay circuit, the output end of the delay circuit is connected with the input end of the opto-coupler driving circuit, the opto-coupler driving circuit comprises a light-emitting diode and two co-source reverse series MOSFET tubes, the output end of the opto-coupler driving circuit is connected with the input end of the switching circuit to control the on-off of the switching circuit, and the output end of the switching circuit is connected with the input end of the three-phase motor, thereby forming a forward rotation path or a reverse rotation path.

[0012] In a preferred embodiment, the switching circuit is composed of thyristors, and the drains of the two MOSFET tubes of the opto-coupler driving circuit are respectively connected with the gates of the two thyristors.

[0013] In a preferred embodiment, it further comprises a first inductor and a seventh resistor, the first inductor is connected between the output end of the opto-coupler driving circuit and the gate of one of the thyristors, and the seventh resistor is connected between the output end of the opto-coupler driving circuit and the gate of the other thyristor.

[0014] In a preferred embodiment, the delay circuit comprises a first capacitor, a first non-inverting buffer, a second non-inverting buffer, a first diode, a first resistor and a second resistor; the input end of the first non-inverting buffer is connected with a forward rotation signal input end or a reverse rotation signal input end, the first diode is reverse connected between the output end of the first non-inverting buffer and the input end of the second non-inverting buffer, the first resistor is connected in series between the first non-inverting buffer and the first diode, the second resistor is connected in parallel across the first diode, the positive end of the first capacitor is connected between the first diode and the second non-inverting buffer, the negative end of the first capacitor is connected to ground, and the output end of the second non-inverting buffer is connected with the input end of the opto-coupler driving circuit.

[0015] In a preferred embodiment, the first non-inverting buffer and the second non-inverting buffer are of the same model.

[0016] The preferred scheme further comprises a first voltage stabilizing diode, a second voltage stabilizing diode, a second diode, a second capacitor, a third capacitor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor and a first NPN triode; the first voltage stabilizing diode and the second voltage stabilizing diode are connected in series in positive direction, the positive terminal of the first voltage stabilizing diode is connected to ground, the negative terminal of the first voltage stabilizing diode is connected to the input terminal of the first non-inverting buffer, the third resistor is connected between the negative terminal of the second voltage stabilizing diode and the negative terminal of the second diode, the positive terminal of the second diode is connected to the positive rotation signal input terminal or the negative rotation signal input terminal, the second capacitor and the fourth resistor are connected in parallel across the first voltage stabilizing diode, the output terminal of the second non-inverting buffer is connected to the fifth resistor, and the fifth resistor is connected to the base of the first NPN triode, the third capacitor and the sixth resistor are connected in parallel across the base and the emitter of the first NPN triode, the emitter of the first NPN triode is connected to ground, and the collector of the first NPN triode is connected to the input terminal of the opto-coupler driving circuit.

[0017] The preferred scheme is that the interlocking circuit is arranged between the delay circuit of the positive rotation circuit and the delay circuit of the negative rotation circuit.

[0018] The preferred scheme is that the interlocking circuit comprises a first MOSFET tube and a second MOSFET tube, the gate of the first MOSFET tube is connected to the delay circuit of the negative rotation circuit, the gate of the second MOSFET tube is connected to the delay circuit of the positive rotation circuit, the drain of the first MOSFET tube is connected to the output terminal of the delay circuit of the positive rotation circuit, the drain of the second MOSFET tube is connected to the output terminal of the delay circuit of the negative rotation circuit, and the sources of the first MOSFET tube and the second MOSFET tube are connected to ground.

[0019] The preferred scheme further comprises a voltage reduction circuit, which comprises a second NPN triode, a first PNP triode and a second PNP triode, the collector of the second NPN triode is connected to the positive rotation signal input terminal and the negative rotation signal input terminal, the base and the emitter of the second NPN triode are connected to ground, the emitter of the first PNP triode is connected to the positive rotation signal input terminal and the negative rotation signal input terminal, the base of the first PNP triode is connected to the emitter of the second PNP triode, the collector of the first PNP triode is connected to the base of the second PNP triode, and the collector of the second PNP triode is connected to ground.

[0020] The preferred scheme further comprises an RC protection circuit, which comprises a capacitor, a resistor and a voltage-dependent resistor, the capacitor and the resistor are connected in series and then connected in parallel across the voltage-dependent resistor, one terminal of the voltage-dependent resistor is connected to any phase of the three-phase power supply, and the other terminal of the voltage-dependent resistor is connected to any input terminal of the three-phase motor.

[0021] After the above scheme is adopted, the application has the following beneficial effects:

[0022] 1. The MOSFET in the optocoupler drive circuit of the present invention has a fast response speed, can quickly respond to changes in the input signal and output the corresponding drive signal, and is suitable for various low-power circuits with a wide range of applications.

[0023] 2. This invention drives the MOSFET through an optocoupler, thus avoiding the electrical sparks that would affect the circuit's operation when physical contacts are in contact.

[0024] 3. This invention utilizes two common-source MOSFETs connected in reverse series at the output of the optocoupler drive circuit to switch the circuit on and off, avoiding the bounce and bounce when the physical contacts are in contact, and has good anti-vibration and shock resistance and long service life.

[0025] 4. The optocoupler driving circuit used in this invention has voltage opto-isolation between the input and output, and has excellent anti-electromagnetic interference performance. When in an excessively high electromagnetic interference state, the MOSFET is in the off state, and no current flows through the entire circuit, so the switching circuit will not experience false turn-on.

[0026] 5. The optocoupler drive circuit of the present invention has a simple structure, which is beneficial to the production and manufacturing of the product and the control of costs. Attached Figure Description

[0027] Figure 1 is a schematic diagram of the forward and reverse rotation control of an existing three-phase motor;

[0028] Figure 2 is a circuit diagram of the forward and reverse rotation module of an existing three-phase motor;

[0029] Figure 3 is a circuit schematic diagram of the present invention.

[0030] Label Explanation:

[0031] 100. Delay circuit for forward rotation; 110. Delay circuit for reverse rotation; 200. Interlock circuit; 300. Optocoupler drive circuit; 400. Switching circuit; 500. Step-down circuit; 600. RC protection circuit. Embodiments of the present invention

[0032] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0033] The application provides a forward and reverse rotation module of a three-phase motor, as shown in Fig. 3, which comprises a forward rotation circuit and a reverse rotation circuit, and each of the forward rotation circuit and the reverse rotation circuit comprises a delay circuit, an interlocking circuit 200, an optical coupling driving circuit 300 and a switching circuit 400; the input end of the delay circuit is connected with the output end of a three-phase power supply, the interlocking circuit 200 is connected in parallel with the delay circuit, the output end of the delay circuit is connected with the input end of the optical coupling driving circuit 300, the optical coupling driving circuit 300 comprises a light-emitting diode and two common-source reverse series MOSFET tubes, the output end of the optical coupling driving circuit 300 is connected with the input end of the switching circuit, so as to control the on-off of the switching circuit 400, and the output end of the switching circuit 400 is connected with the input end of the three-phase motor, thereby forming a forward rotation path or a reverse rotation path.

[0034] In the embodiment, the optical coupling driving circuit 300 comprises a common optical coupling driving circuit PO1, a forward rotation optical coupling driving circuit PO2, PO3 and a reverse rotation optical coupling driving circuit PO4, PO5. One end of the two forward rotation optical coupling driving circuits PO2 and PO3 connected in series is connected with the collector of the first NPN transistor Q4 of the output end of the delay circuit 100 of the forward rotation circuit, and the other end is connected with the common optical coupling driving circuit PO1. One end of the two reverse rotation optical coupling driving circuits PO4 and PO5 connected in series is connected with the collector of the NPN transistor Q5 of the output end of the delay circuit 110 of the reverse rotation circuit, and the other end is connected with the common optical coupling driving circuit PO1.

[0035] Further referring to Fig. 3, in the common optical coupling driving circuit PO1, the anode end of the light-emitting diode and the power supply VDD are further connected in series with a resistor R27. The drain 5 of the first MOSFET tube is connected to the gate of the thyristor Q12, and the resistor R28 and the capacitor C13 are connected in parallel between the gate and the cathode of the thyristor Q12, respectively. The drain 4 of the second MOSFET tube is connected to the gate of the thyristor Q11 after being connected in series with the resistor R38, and the resistor R29 and the capacitor C14 are connected in parallel between the gate and the cathode of the thyristor Q11, respectively. The anode of the thyristor Q11 and the cathode of the thyristor Q12 are connected to one phase of the three-phase power supply L1, respectively, and the cathode of the thyristor Q11 and the anode of the thyristor Q12 are connected to one input end U of the three-phase motor, respectively. It is worth noting that in other embodiments, the common optical coupling driving circuit PO1 can also use an ordinary alternating current optical coupling driving, which can be easily realized by those skilled in the art.

[0036] As shown in Fig. 3, it further comprises a first inductor L4 and a seventh resistor R39, the first inductor L4 is connected between the output end of the optical coupling driving circuit 300 and the gate of one of the thyristors, and the seventh resistor R39 is connected between the output end of the optical coupling driving circuit 300 and the gate of the other thyristor.

[0037] Different from the common opto-coupler driving circuit PO1, the drain 5 of the first MOSFET tube of the forward opto-coupler driving circuit PO2 is connected to the cathode of the thyristor Q17 in series with the first inductor L4, and the drain 4 of the second MOSFET tube of the forward opto-coupler driving circuit PO2 is connected to the cathode of the thyristor Q19 in series with the seventh resistor R39. In addition, the other settings are the same as those of the common opto-coupler driving circuit PO1, and are adaptively connected to the three-phase power supply and the three-phase motor. The forward opto-coupler driving circuit PO3 is the same as the forward opto-coupler driving circuit PO2, and the specific circuit is shown in FIG. 3, which will not be described in detail.

[0038] Different from the forward opto-coupler driving circuits PO2 and PO3, the drain 5 of the first MOSFET tube of the reverse opto-coupler driving circuit PO4 is connected to the gate of the thyristor Q20 in series with the resistor R41, and the drain 4 of the second MOSFET tube is connected to the gate of the thyristor Q18 in series with the inductor L3. The anode of the thyristor Q18 and the cathode of the thyristor Q20 are respectively connected to one input end V of the three-phase motor, and the cathode of the thyristor Q18 and the anode of the thyristor Q20 are respectively connected to one phase L3 of the three-phase power supply. In addition, the other settings are the same as those of the forward opto-coupler driving circuits PO2 and PO3, and are adaptively connected to the three-phase power supply and the three-phase motor, so as to realize the reverse rotation of the three-phase motor. The specific circuit is shown in FIG. 3. The embodiment also provides a forward indication lamp LD2 and a reverse indication lamp LD3, which can be easily realized by those skilled in the art, and will not be described in detail.

[0039] As shown in FIG. 3, the switching circuit 400 is composed of thyristors, and the drains of the two MOSFET tubes of the opto-coupler driving circuit 300 are respectively connected to the gates of the two thyristors. The switching circuit 400 of the embodiment adopts unidirectional thyristor switches, and the two MOSFET tubes in common source and reverse series are matched with the two unidirectional thyristors. When in the state of excessive electromagnetic interference or excessive vibration impact, the MOSFET tube is in the off state, and no current flows through the whole circuit, so that the switching circuit 400 will not be misdirected. Of course, in other embodiments, the switching circuit 400 can also select other semiconductor switches to realize.

[0040] As shown in Fig. 3, the delay circuit 100 of the forward rotation circuit of the embodiment comprises a first capacitor C7, a first non-inverting buffer IC2A, a second non-inverting buffer IC2D, a first diode D6, a first resistor R9 and a second resistor R11; the input end of the first non-inverting buffer IC2A is connected to the forward rotation signal input end F+, the first diode D6 is reversely connected between the output end of the first non-inverting buffer IC2A and the input end of the second non-inverting buffer IC2D, the first resistor R9 is connected between the first non-inverting buffer IC2A and the first diode D6, the second resistor R11 is connected across the first diode D6, the positive end of the first capacitor C7 is connected between the first diode D6 and the second non-inverting buffer IC2D, the negative end of the first capacitor C7 is connected to the ground, and the output end of the second non-inverting buffer IC2D is connected to the input end of the opto-coupler driving circuit. The delay circuit 110 of the reverse rotation circuit of the embodiment is arranged in the same way as the delay circuit 100 of the forward rotation circuit, as shown in Fig. 3.

[0041] As shown in Fig. 3, the first non-inverting buffer IC2A and the second non-inverting buffer IC2D are of the same type. In the embodiment, the first non-inverting buffer IC2A and the second non-inverting buffer IC2D are of the same type, which facilitates production and debugging.

[0042] As shown in Fig. 3, the delay circuit 100 of the forward rotation circuit of the embodiment further comprises a first zener diode D9, a second zener diode D11, a second diode D5, a second capacitor C5, a third capacitor C11, a third resistor R5, a fourth resistor R7, a fifth resistor R13, a sixth resistor R21 and a first NPN transistor Q4; the first zener diode D9 and the second zener diode D11 are connected in series, the positive end of the first zener diode D9 is connected to the ground, the negative end of the first zener diode D9 is connected to the input end of the first non-inverting buffer IC2A, the third resistor R5 is connected between the negative end of the second zener diode D11 and the negative end of the second diode D5, the positive end of the second diode D5 is connected to the forward rotation signal input end F+, the second capacitor C5 and the fourth resistor R7 are connected across the first zener diode D9, the output end of the second non-inverting buffer IC2D is connected to the base of the first NPN transistor Q4 through the fifth resistor R13, the third capacitor C11 and the sixth resistor R21 are connected between the base and the emitter of the first NPN transistor Q4, the emitter of the first NPN transistor Q4 is connected to the ground, and the collector of the first NPN transistor Q4 is connected to the input end of the opto-coupler driving circuit. The delay circuit 110 of the reverse rotation circuit of the embodiment is arranged in the same way as the delay circuit 100 of the forward rotation circuit, as shown in Fig. 3. In other embodiments, other solutions can also be used.

[0043] As shown in Fig. 3, the interlocking circuit 200 is arranged between the delay circuit 100 of the forward rotation circuit and the delay circuit 110 of the reverse rotation circuit. In the present embodiment, when the control signal is applied to the forward signal input terminal F+ and the reverse signal input terminal R+ at the same time, the forward and reverse signals are simultaneously turned off due to the arrangement of the interlocking circuit 200, thereby avoiding short circuit between the circuits and damaging the product.

[0044] As shown in Fig. 3, the interlocking circuit 200 comprises a first MOSFET tube Q2 and a second MOSFET tube Q3. The gate of the first MOSFET tube Q2 is connected to the delay circuit 110 of the reverse rotation circuit, the gate of the second MOSFET tube Q3 is connected to the delay circuit 100 of the forward rotation circuit, the drain of the first MOSFET tube Q2 is connected to the output terminal of the delay circuit 100 of the forward rotation circuit, the drain of the second MOSFET tube Q3 is connected to the output terminal of the delay circuit 110 of the reverse rotation circuit, and the sources of the first MOSFET tube Q2 and the second MOSFET tube Q3 are connected to the ground, respectively.

[0045] With reference to Fig. 3 in detail, the input terminal of the non-inverting buffer IC2C is connected between the output terminal of the non-inverting buffer IC2E of the delay circuit 110 of the reverse rotation circuit and the resistor R10, the output terminal of the non-inverting buffer IC2C is connected to the first input terminal of the double diode D14, the output terminal of the non-inverting buffer IC2F in the delay circuit 110 of the reverse rotation circuit is connected to the second input terminal of the double diode D14, the output terminal of the double diode D14 is connected to the base of the first MOSFET tube Q2 through the resistor R19, the resistor R15 is connected in parallel between the output terminal of the double diode D14 and the resistor R19, the first terminal of the resistor R15 is connected to the first terminal of the capacitor C9, the second terminal of the capacitor C9 is connected to the ground, the resistor R17 is connected in parallel between the first terminal of the resistor R15 and the second terminal of the capacitor C9, and the collector of the first MOSFET tube Q2 is connected to the base of the first NPN transistor Q4 of the delay circuit 100 of the forward rotation circuit. The remaining part of the interlocking circuit 200 can be arranged in the same way, which will not be described in detail. The non-inverting buffers mentioned above are all of the same type.

[0046] As shown in Fig. 3, the voltage reduction circuit 500 is further provided, which comprises a second NPN transistor Q1, a first PNP transistor Q6 and a second PNP transistor Q7. The collector of the second NPN transistor Q1 is connected to the forward signal input terminal F+ and the reverse signal input terminal R+, the base and the emitter of the second NPN transistor Q1 are connected to the ground, respectively. The emitter of the first PNP transistor Q6 is connected to the forward signal input terminal F+ and the reverse signal input terminal R+, the base of the first PNP transistor Q6 is connected to the emitter of the second PNP transistor Q7, the collector of the first PNP transistor Q6 is connected to the base of the second PNP transistor Q7, and the collector of the second PNP transistor Q7 is connected to the ground.

[0047] In this embodiment, the anode of diode D1 and the anode of diode D2 are connected to the forward signal input end F+ and the reverse signal input end R+ respectively, the cathode of diode D2 is connected in parallel to the cathode of diode D1, the cathode of diode D1 is connected to the collector of the second NPN transistor Q1 after being connected in series with resistor R1, the first end of capacitor C1 and bidirectional voltage stabilizing diode D13 are connected between resistor R1 and the collector of the second NPN transistor Q1 respectively, the second end of capacitor C1 and bidirectional voltage stabilizing diode D13 are grounded respectively, resistor R2 is connected between the collector and the base of the second NPN transistor Q1, the cathode of voltage stabilizing diode D8 is connected to the second NPN transistor Q1, the anode of voltage stabilizing diode D8 is grounded, the emitter of the second NPN transistor Q1 is connected in parallel to capacitor C2, capacitor C3 and capacitor C4 respectively and then grounded, the emitter of the first PNP transistor Q6 is connected between resistor R1 and the collector of the second NPN transistor Q1, resistor R3 is connected between the emitter and the base of the first PNP transistor Q6, and resistor R4 is connected between the base and the collector of the second PNP transistor Q7. The specific circuit diagram is shown in FIG. 3. Of course, other schemes can also be used in other embodiments.

[0048] As shown in FIG. 3, the RC protection circuit 600 is further included, which comprises a capacitor, a resistor and a pressure sensitive resistor. The capacitor and the resistor are connected in series and then connected in parallel to the pressure sensitive resistor. One end of the pressure sensitive resistor is connected to any phase power supply of the three-phase power supply, and the other end of the pressure sensitive resistor is connected to any input end of the three-phase motor.

[0049] Taking the L1 phase power supply of the three-phase power supply and the input end U of the three-phase motor as an example, the capacitor CX5 and the resistor R45 are connected in series and then connected in parallel to the pressure sensitive resistor MOV5. One end of the pressure sensitive resistor MOV5 is connected to the L1 phase power supply of the three-phase power supply, and the other end of the pressure sensitive resistor MOV5 is connected to the input end U of the three-phase motor. Similarly, the other phase power supply of the three-phase power supply and the other input end of the three-phase motor can be adaptively set. The RC protection circuit 600 arranged between the three-phase power supply and the three-phase motor in this embodiment can improve the stability and reliability of the circuit, protect the three-phase motor from potential damage, and improve the performance of the circuit.

[0050] The working principle of the present application is as follows:

[0051] When the forward input end F+ and the common ground end GND have a specified forward voltage applied, the capacitor C7 is first delayed for a period of time through the non-inverting buffer IC2A. When the NPN transistor Q4 is turned on, the optocoupler driving circuit PO1, PO2 and PO3 are synchronously turned on. At this time, the switches connected in series with the gates of the unilateral thyristors Q11, Q12, Q19, Q17, Q14 and Q16 are all turned on, thereby triggering the unilateral thyristors Q11, Q12, Q19, Q17, Q14 and Q16 to be turned on, and the motor starts to rotate forward.

[0052] When the input end R+ and the common ground end GND have a specified reverse voltage applied, the capacitor C8 is first delayed for a period of time by the non-inverting buffer IC2E, the NPN transistor Q5 is turned on, the optocoupler drive circuit PO1, PO4 and PO5 are synchronously turned on, at this time the gates of the thyristors Q11, Q12, Q18, Q20, Q13 and Q15 connected in series with the one-way thyristors Q11, Q12, Q18, Q20, Q13 and Q15 are turned on, thereby triggering the thyristors Q11, Q12, Q18, Q20, Q13 and Q15 to be turned on, and the motor starts to reverse.

[0053] When the F+ and R+ simultaneously apply control signals, the first MOSFET tube Q2 and the second MOSFET tube Q3 are simultaneously turned on by the non-inverting buffer IC2B, IC2D, IC2C and IC2F, and the current of the positive and negative control signals is pulled to realize the simultaneous closing of the output of the positive and negative signals.

[0054] The above only describes the preferred embodiments of the present application, and is not a limitation on the design of the present application. Any equivalent changes made according to the key design of the present application fall within the scope of protection of the present application.

Claims

1. A forward-reverse module of a three-phase motor, characterized by: The application relates to a three-phase motor control circuit, which comprises a forward rotation circuit and a reverse rotation circuit, wherein each of the forward rotation circuit and the reverse rotation circuit comprises a delay circuit, an interlocking circuit, a photo-coupler driving circuit and a switch circuit; the input end of the delay circuit is connected with the output end of a three-phase power supply; the interlocking circuit is connected in parallel with the delay circuit; the output end of the delay circuit is connected with the input end of the photo-coupler driving circuit; the photo-coupler driving circuit comprises a light-emitting diode and two co-source reverse series MOSFET tubes; the output end of the photo-coupler driving circuit is connected with the input end of the switch circuit to control the on-off of the switch circuit; and the output end of the switch circuit is connected with the input end of a three-phase motor to form a forward rotation path or a reverse rotation path.

2. A forward-reverse module for a three-phase electric motor as claimed in claim 1, characterized in that: The switch circuit is composed of thyristors, and the drain electrodes of the two MOSFET tubes of the photo-coupler driving circuit are respectively connected with the gate electrodes of the two thyristors.

3. A forward-reverse module for a three-phase electric motor as claimed in claim 2, characterized in that: The application further comprises a first inductor and a seventh resistor, wherein the first inductor is connected between the output end of the photo-coupler driving circuit and the gate electrode of one of the thyristors, and the seventh resistor is connected between the output end of the photo-coupler driving circuit and the gate electrode of the other thyristor.

4. A forward-reverse module for a three-phase electric motor as claimed in claim 1, characterized in that: The delay circuit comprises a first capacitor, a first non-inverting buffer, a second non-inverting buffer, a first diode, a first resistor and a second resistor; the input end of the first non-inverting buffer is connected with a forward rotation signal input end or a reverse rotation signal input end; the first diode is reversely connected between the output end of the first non-inverting buffer and the input end of the second non-inverting buffer; the first resistor is connected in series between the first non-inverting buffer and the first diode; the second resistor is connected in parallel with the first diode; the positive electrode end of the first capacitor is connected between the first diode and the second non-inverting buffer; the negative electrode end of the first capacitor is connected with the ground; and the output end of the second non-inverting buffer is connected with the input end of the photo-coupler driving circuit.

5. A forward-reverse module for a three-phase electric motor as claimed in claim 4, characterized in that: The model of the first non-inverting buffer and the second non-inverting buffer is the same.

6. A forward-reverse module for a three-phase motor as claimed in claim 4, characterized in that: The application further comprises a first voltage stabilizing diode, a second voltage stabilizing diode, a second diode, a second capacitor, a third capacitor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor and a first NPN triode; the first voltage stabilizing diode and the second voltage stabilizing diode are connected in series in a forward direction; the positive electrode end of the first voltage stabilizing diode is connected with the ground; the negative electrode end of the first voltage stabilizing diode is connected with the input end of the first non-inverting buffer; the third resistor is connected in series between the negative electrode end of the second voltage stabilizing diode and the negative electrode end of the second diode; the positive electrode end of the second diode is connected with the forward rotation signal input end or the reverse rotation signal input end; the second capacitor and the fourth resistor are respectively connected in parallel with the first voltage stabilizing diode; the output end of the second non-inverting buffer is connected with the fifth resistor and then with the base of the first NPN triode; the third capacitor and the sixth resistor are respectively connected between the base and the emitter of the first NPN triode; the emitter of the first NPN triode is connected with the ground; and the collector of the first NPN triode is connected with the input end of the photo-coupler driving circuit.

7. A forward-reverse module for a three-phase motor as claimed in claim 1, characterized in that: The interlocking circuit is arranged between the delay circuit of the forward rotation circuit and the delay circuit of the reverse rotation circuit.

8. A forward-reverse module of a three-phase motor as claimed in claim 7, characterized in that: The interlocking circuit comprises a first MOSFET tube and a second MOSFET tube, the gate of the first MOSFET tube is connected to the delay circuit of the reverse circuit, the gate of the second MOSFET tube is connected to the delay circuit of the positive rotation circuit, the drain of the first MOSFET tube is connected to the output end of the delay circuit of the positive rotation circuit, the drain of the second MOSFET tube is connected to the output end of the delay circuit of the reverse circuit, and the sources of the first MOSFET tube and the second MOSFET tube are respectively connected to the ground.

9. A forward-reverse module for a three-phase electric motor as claimed in claim 1, characterized in that: The voltage reduction circuit comprises a second NPN transistor, a first PNP transistor and a second PNP transistor, the collector of the second NPN transistor is connected to the positive rotation signal input end and the reverse signal input end, the base and the emitter of the second NPN transistor are respectively connected to the ground, the emitter of the first PNP transistor is connected to the positive rotation signal input end and the reverse signal input end, the base of the first PNP transistor is connected to the emitter of the second PNP transistor, the collector of the first PNP transistor is connected to the base of the second PNP transistor, and the collector of the second PNP transistor is connected to the ground.

10. A forward-reverse module for a three-phase electric motor as claimed in claim 1, characterized in that: The RC protection circuit comprises a capacitor, a resistor and a voltage-dependent resistor, the capacitor and the resistor are connected in series and are connected across the voltage-dependent resistor, one end of the voltage-dependent resistor is connected to any phase of the three-phase power supply, and the other end of the voltage-dependent resistor is connected to any input end of the three-phase motor.

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