Forward and reverse rotation module of three-phase motor

Abstract

The utility model discloses a forward and reverse rotation module of a three-phase motor, 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 time delay circuit, an interlocking circuit, an optocoupler driving circuit and a switching circuit. The input end of the time delay circuit is connected with the output end of a three-phase power supply, the interlocking circuit is connected to the time delay circuit in parallel, the output end of the time delay circuit is connected with the input end of the optical coupler driving circuit, the optical coupler driving circuit comprises a light emitting diode and two common-source-electrode metal-oxide-semiconductor field effect transistor (MOSFET) tubes which are connected in series reversely, and the two common-source-electrode metal-oxide-semiconductor field effect transistor (MOSFET) tubes are connected in parallel. The output end of the optocoupler 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 to form a forward rotation path or a reverse rotation path. The switch circuit has good anti-electromagnetic interference performance and anti-vibration and anti-impact capability, and when the switch circuit is in an over-high electromagnetic interference state or an over-high vibration and anti-impact state, the switch circuit is not mistakenly conducted.

Description

Technical Field

[0001] The utility model relates to the technical field of motor control, in particular to a forward and reverse rotation module of a three-phase motor. Background Art

[0002] The working principle of the three-phase asynchronous motor is based on the principle of electromagnetic induction. When a three-phase symmetrical alternating current passes through the stator input end, a rotating magnetic field is generated between the stator and the rotor. The rotating magnetic field cuts the rotor input end, generating an induced electromotive force and current in the rotor circuit. Under the action of the rotating magnetic field, the current in the rotor conductor is acted upon by force to cause the rotor to rotate. The direction of rotation of the rotor is consistent with the direction of the rotating magnetic field. The direction of rotation of the motor can be changed by changing the direction of the rotating magnetic field. To change the direction of the rotating magnetic field, just swap any two of the three power lines of the three-phase motor. For example Figure 1 As shown in the figure, when K1', K2', K3' are turned on and K4', K5' are turned off, the motor M rotates forward; when K1', K4', K5' are turned on and K2', K3' are turned off, the motor M rotates reversely. K1' is a common phase and can be directly short-circuited with a wire without affecting the function. In any case, K2' and K5' as well as K3' and K4' are not allowed to be turned on at the same time, otherwise it will cause a phase-to-phase short circuit and damage.

[0003] Generally, electromagnetic relays, contactors, motor forward and reverse modules, etc. can be used to replace the power lines, thereby realizing the forward and reverse functions of the motor. Figure 2 As shown, the existing motor forward and reverse modules usually use contactless semiconductor switches (such as thyristors) to realize the switching function, which are composed of 4 or 5 solid-state relays (each solid-state relay is composed of an optocoupler, a thyristor and some other auxiliary electronic components) and some other interlocking delay circuits.

[0004] However, these prior arts have the following deficiencies:

[0005] 1. The action time of electromagnetic relays and contactors is slow, and they cannot realize the reverse braking function, so their application scope is easily limited.

[0006] 2. The output end of the electromagnetic relay and contactor uses a contact method to realize the switching function, which is easy to generate electric sparks when switching on and off, affecting the use of the circuit.

[0007] 3. Electromagnetic relays and contactors have poor vibration resistance, short overall life and low reliability.

[0008] 4. Ordinary solid-state relays have weak anti-electromagnetic interference capabilities. When subjected to strong external electromagnetic interference, they are prone to mis-conduction, causing product damage due to phase-to-phase short circuit.

[0009] 5. Solid-state relays with strong anti-electromagnetic interference capabilities are too expensive. Utility Model Content

[0010] The purpose of the utility model is to provide a forward and reverse rotation module of a three-phase motor to solve the technical problems mentioned in the background technology.

[0011] To achieve the above-mentioned purpose, the solution of the utility model is: a forward and reverse module of a three-phase motor, including a forward circuit and a reverse circuit, and the forward circuit and the reverse circuit both include a delay circuit, an interlocking circuit, an optocoupler drive circuit and a switch circuit; the input end of the delay circuit is connected to the output end of the 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 optocoupler drive circuit, the optocoupler drive circuit includes a light-emitting diode and two MOSFET tubes with a common source connected in reverse series, the output end of the optocoupler drive circuit is connected to the input end of the switch circuit to control the on and off of the switch circuit, and the output end of the switch circuit is connected to the input end of the three-phase motor, thereby forming a forward path or a reverse path.

[0012] In a preferred embodiment, the switch circuit is composed of a thyristor, and the drains of the two MOSFET tubes of the optocoupler drive circuit are respectively connected to the gates of the two thyristors.

[0013] The preferred solution further includes a first inductor and a seventh resistor, wherein the first inductor is connected between the output end of the optocoupler drive circuit and the gate of one of the thyristors, and the seventh resistor is connected between the output end of the optocoupler drive circuit and the gate of the other thyristor.

[0014] In a preferred embodiment, the delay circuit includes 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 to the forward signal input end or the reverse signal input end, the first diode is reversely connected in series 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 at both ends of the first diode, the positive terminal of the first capacitor is connected between the first diode and the second non-inverting buffer, the negative terminal of the first capacitor is grounded, and the output end of the second non-inverting buffer is connected to the input end of the optocoupler drive circuit.

[0015] Preferably, the first non-inverting buffer and the second non-inverting buffer are of the same model.

[0016] The preferred scheme also includes 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 transistor; the first voltage-stabilizing diode and the second voltage-stabilizing diode are connected in series in a forward direction, the positive terminal of the first voltage-stabilizing diode is grounded, 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 in series 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 forward signal input terminal or the reverse signal input terminal, the second capacitor and the fourth resistor are respectively connected in parallel at both ends of the first voltage-stabilizing diode, the output terminal of the second non-inverting buffer is connected in series with the fifth resistor and then connected to the base of the first NPN transistor, the third capacitor and the sixth resistor are respectively connected in parallel between the base and emitter of the first NPN transistor, the emitter of the first NPN transistor is grounded, and the collector of the first NPN transistor is connected to the input terminal of the optocoupler drive circuit.

[0017] In a preferred embodiment, the interlocking circuit is arranged between the delay circuit of the forward rotation circuit and the delay circuit of the reverse rotation circuit.

[0018] In a preferred embodiment, the interlocking circuit includes a first MOSFET tube and a second MOSFET tube, the gate of the first MOSFET tube is connected to the delay circuit of the reversing circuit, the gate of the second MOSFET tube is connected to the delay circuit of the forward circuit, the drain of the first MOSFET tube is connected to the output end of the delay circuit of the forward circuit, the drain of the second MOSFET tube is connected to the output end of the delay circuit of the reversing circuit, and the sources of the first MOSFET tube and the second MOSFET tube are grounded respectively.

[0019] The preferred embodiment also includes a step-down circuit, which includes a second NPN transistor, a first PNP transistor, and a second PNP transistor, the collector of the second NPN transistor is connected to the forward signal input terminal and the reverse signal input terminal, the base and emitter of the second NPN transistor are grounded respectively, the emitter of the first PNP transistor is connected to the forward signal input terminal and the reverse signal input terminal, 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 grounded.

[0020] The preferred embodiment also includes an RC protection circuit, which includes a capacitor, a resistor and a varistor. The capacitor and the resistor are connected in series and connected to both ends of the varistor. One end of the varistor is connected to any phase of the three-phase power supply, and the other end of the varistor is connected to any input end of the three-phase motor.

[0021] After adopting the above scheme, the beneficial effects of the utility model are:

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

[0023] 2. The utility model drives the MOSFET tube through an optical coupler, thereby avoiding the influence of electric sparks generated when physical contacts come into contact with each other and affecting the use of the circuit.

[0024] 3. The utility model utilizes two MOSFET tubes with common source electrodes connected in reverse series at the output end of the optocoupler drive circuit to realize the on-off of the switch circuit, avoiding the jitter rebound when the physical contacts are in contact, having good vibration and impact resistance and long service life.

[0025] 4. The optocoupler drive circuit adopted by the utility model has voltage photoelectric isolation between input and output, and has excellent anti-electromagnetic interference performance. When it is in an excessively high electromagnetic interference state, the MOSFET tube is in the off state, no current flows through the entire circuit, and the switch circuit will not be misconnected.

[0026] 5. The optocoupler driving circuit of the utility model has a simple structure, which is beneficial to product manufacturing and cost control. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0029] Figure 3 It is a circuit schematic diagram of the utility model.

[0030] Description of labels:

[0031] 100. Delay circuit of the forward circuit; 110. Delay circuit of the reverse circuit; 200. Interlocking circuit; 300. Optocoupler driving circuit; 400. Switching circuit; 500. Buck circuit; 600. RC protection circuit. DETAILED DESCRIPTION

[0032] The utility model is now further described in conjunction with the accompanying drawings and specific implementation methods.

[0033] The utility model provides a forward and reverse module for a three-phase motor. Figure 3As shown, it includes a forward circuit and a reverse circuit, and the forward circuit and the reverse circuit both include a delay circuit, an interlocking circuit 200, an optocoupler driving circuit 300 and a switch circuit 400; the input end of the delay circuit is connected to the output end of the three-phase power supply, the interlocking circuit 200 is connected in parallel to the delay circuit, the output end of the delay circuit is connected to the input end of the optocoupler driving circuit 300, the optocoupler driving circuit 300 includes a light-emitting diode and two MOSFET tubes with a common source connected in reverse series, the output end of the optocoupler driving circuit 300 is connected to the input end of the switch circuit to control the on and off of the switch circuit 400, and the output end of the switch circuit 400 is connected to the input end of the three-phase motor, thereby forming a forward path or a reverse path.

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

[0035] Further references Figure 3 In the common optocoupler drive circuit PO1, a resistor R27 is also connected in series between the positive terminal of the light-emitting diode and the power supply VDD. Among them, 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 respectively connected in parallel between the gate and the cathode of the thyristor Q12. The drain 4 of the second MOSFET tube is connected in series with the resistor R38 and then connected to the gate of the thyristor Q11, and the resistor R29 and the capacitor C14 are respectively connected in parallel between the gate and the cathode of the thyristor Q11. The anode of the thyristor Q11 and the cathode of the thyristor Q12 are respectively connected to one of the phase power supplies L1 of the three-phase power supply, and the cathode of the thyristor Q11 and the anode of the thyristor Q12 are respectively connected to one of the input terminals U of the three-phase motor. It is worth noting that in other embodiments, the common optocoupler drive circuit PO1 can also be driven by a common AC optocoupler, which can be easily realized by those skilled in the art.

[0036] like Figure 3 As shown, it also includes a first inductor L4 and a seventh resistor R39, wherein the first inductor L4 is connected between the output end of the optocoupler drive circuit 300 and the gate of one of the thyristors, and the seventh resistor R39 is connected between the output end of the optocoupler drive circuit 300 and the gate of another thyristor.

[0037] Different from the common optocoupler drive circuit PO1, the first inductor L4 is connected in series between the drain 5 of the first MOSFET tube of the forward optocoupler drive circuit PO2 and the cathode of the thyristor Q17, and the seventh resistor R39 is connected in series between the drain 4 of the second MOSFET tube of the forward optocoupler drive circuit PO2 and the cathode of the thyristor Q19. In addition, the other settings are the same as the common optocoupler drive circuit PO1, and are adaptively connected to the three-phase power supply and the three-phase motor. The settings of the forward optocoupler drive circuit PO3 are the same as those of the forward optocoupler drive circuit PO2. For details of the circuit, see Figure 3 , I will not go into details about this.

[0038] Different from the forward optocoupler drive circuits PO2 and PO3, the drain 5 of the first MOSFET tube of the reverse optocoupler drive circuit PO4 is connected in series with the resistor R41 and then connected to the gate of the thyristor Q20, the drain 4 of the second MOSFET tube is connected in series with the inductor L3 and then connected to the gate of the thyristor Q18, the anode of the thyristor Q18 and the cathode of the thyristor Q20 are respectively connected to one of the input terminals 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 of the phase power supply L3 of the three-phase power supply. In addition, the other settings are the same as the forward optocoupler drive circuits PO2 and PO3, and are adaptively connected to the three-phase power supply and the three-phase motor to achieve the reversal of the three-phase motor. For details of the specific circuit, see Figure 3 The present embodiment also provides a forward indicator light LD2 and a reverse indicator light LD3, which can be easily implemented by those skilled in the art and will not be described in detail.

[0039] like Figure 3 As shown, the switch circuit 400 is composed of thyristors, and the drains of the two MOSFET tubes of the optocoupler drive circuit 300 are respectively connected to the gates of the two thyristors. The switch circuit 400 of this embodiment adopts a unidirectional thyristor switch, and two MOSFET tubes with a common source connected in reverse series cooperate with two unidirectional thyristors. When in a state of too high electromagnetic interference or too high vibration shock, the MOSFET tube is in a turned-off state, and no current flows through the entire loop, and the switch circuit 400 will not be misconnected. Of course, in other embodiments, the switch circuit 400 can also be implemented by selecting other semiconductor switches.

[0040] like Figure 3As shown, the delay circuit 100 of the forward conversion circuit of this embodiment includes 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 conversion signal input end F+, the first diode D6 is reversely connected in series 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 in series between the first non-inverting buffer IC2A and the first diode D6, the second resistor R11 is connected in parallel at both ends of the first diode D6, the positive terminal of the first capacitor C7 is connected between the first diode D6 and the second non-inverting buffer IC2D, the negative terminal of the first capacitor C7 is grounded, and the output end of the second non-inverting buffer IC2D is connected to the input end of the optocoupler driving circuit. For the delay circuit 110 of the inversion circuit of this embodiment, its configuration is the same as that of the delay circuit 100 of the forward conversion circuit, see for details. Figure 3 .

[0041] like Figure 3 As shown, the first non-inverting buffer IC2A and the second non-inverting buffer IC2D are of the same model. In this embodiment, the first non-inverting buffer IC2A and the second non-inverting buffer IC2D are of the same model, which is convenient for production and debugging.

[0042] like Figure 3 As shown, the delay circuit 100 of the forward conversion circuit of this embodiment further includes a first voltage zener diode D9, a second voltage 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 voltage zener diode D9 is connected in series with the second voltage zener diode D11 in a forward direction, the positive terminal of the first voltage zener diode D9 is grounded, the negative terminal of the first voltage zener diode D9 is connected to the input terminal of the first non-inverting buffer IC2A, and the third resistor R5 is connected in series with the second voltage zener diode D 11 and the negative terminal of the second diode D5, the positive terminal of the second diode D5 is connected to the forward signal input terminal F+, the second capacitor C5 and the fourth resistor R7 are respectively connected in parallel at both ends of the first voltage regulator diode D9, the output end of the second non-inverting buffer IC2D is connected in series with the fifth resistor R13 and then connected to the base of the first NPN transistor Q4, the third capacitor C11 and the sixth resistor R21 are respectively connected in parallel between the base and emitter of the first NPN transistor Q4, the emitter of the first NPN transistor Q4 is grounded, and the collector of the first NPN transistor Q4 is connected to the input end of the optical coupling driving circuit. For the delay circuit 110 of the inversion circuit of this embodiment, its setting is the same as the delay circuit 100 of the forward circuit, see for details Figure 3 , other solutions may also be adopted in other embodiments.

[0043] like Figure 3 As shown, the interlock circuit 200 is arranged between the delay circuit 100 of the forward circuit and the delay circuit 110 of the reverse circuit. In this 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 interlock circuit 200 is arranged so that the positive and negative signals are simultaneously turned off for output, thereby preventing a short circuit between the circuits from damaging the product.

[0044] like Figure 3 As shown, the interlocking circuit 200 includes 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 reversing circuit, the gate of the second MOSFET tube Q3 is connected to the delay circuit 100 of the forward circuit, the drain of the first MOSFET tube Q2 is connected to the output end of the delay circuit 100 of the forward circuit, the drain of the second MOSFET tube Q3 is connected to the output end of the delay circuit 110 of the reversing circuit, and the sources of the first MOSFET tube Q2 and the second MOSFET tube Q3 are grounded respectively.

[0045] Specific reference Figure 3 The input end of the non-inverting buffer IC2C is connected between the output end of the non-inverting buffer IC2E of the delay circuit 110 of the inverting circuit and the resistor R10, the output end of the non-inverting buffer IC2C is connected to the first input end of the dual diode D14, in the delay circuit 110 of the inverting circuit, the output end of the non-inverting buffer IC2F is connected to the second input end of the dual diode D14, the output end of the dual diode D14 is connected in series with the resistor R19 and then connected to the base of the first MOSFET tube Q2, the first end of the resistor R15 is connected in parallel between the output end of the dual diode D14 and the resistor R19, the second end of the resistor R15 is connected to the first end of the capacitor C9, the second end of the capacitor C9 is grounded, the resistor R17 is connected in parallel between the first end of the resistor R15 and the second end 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 conversion circuit. Similarly, the interlocking circuit 200 of the remaining parts can be set in the same way, which will not be described in detail, and the non-inverting buffers mentioned above are all of the same model.

[0046] like Figure 3As shown, it also includes a step-down circuit 500, which includes 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 emitter of the second NPN transistor Q1 are grounded 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 grounded.

[0047] In this embodiment, the positive terminals of the diode D1 and the diode D2 are connected to the forward signal input terminal F+ and the reverse signal input terminal R+, respectively, the negative terminal of the diode D2 is connected in parallel to the negative terminal of the diode D1, the negative terminal of the diode D1 is connected in series with the resistor R1 and then connected to the collector of the second NPN transistor Q1, the first terminals of the capacitor C1 and the bidirectional voltage regulator diode D13 are connected between the resistor R1 and the collector of the second NPN transistor Q1, the second terminals of the capacitor C1 and the bidirectional voltage regulator diode D13 are grounded, respectively, the resistor R2 is connected to the second NPN transistor The cathode terminal of the voltage zener diode D8 is connected to the second NPN transistor Q1, the anode terminal of the voltage zener diode D8 is grounded, the emitter of the second NPN transistor Q1 is connected in parallel to capacitors C2, C3 and C4 respectively and then grounded, the emitter of the first PNP transistor Q6 is connected between the resistor R1 and the collector of the second NPN transistor Q1, the resistor R3 is connected between the emitter and base of the first PNP transistor Q6, and the resistor R4 is connected between the base and collector of the second PNP transistor Q7. For a specific circuit diagram, see Figure 3 Of course, other solutions may also be adopted in other embodiments.

[0048] like Figure 3 As shown, it also includes an RC protection circuit 600, which includes a capacitor, a resistor and a varistor. The capacitor and the resistor are connected in series and connected to both ends of the varistor. One end of the varistor is connected to any phase power supply of the three-phase power supply, and the other end of the varistor 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 terminal U of the three-phase motor as an example, the capacitor CX5 and the resistor R45 are connected in series and connected to the two ends of the varistor MOV5, one end of the varistor MOV5 is connected to the L1 phase power supply of the three-phase power supply, and the other end of the varistor MOV5 is connected to the input terminal U of the three-phase motor. Similarly, other phase power supplies of the three-phase power supply and other input terminals of the three-phase motor can be adaptively set. In this embodiment, the RC protection circuit 600 is set between the three-phase power supply and the three-phase motor to 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 utility model is as follows:

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

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

[0053] When F+ and R+ apply control signals at the same time, the first MOSFET tube Q2 and the second MOSFET tube Q3 are turned on at the same time through the non-inverting buffers IC2B, IC2D, IC2C and IC2F, and the currents of the positive and negative control signals are pulled to the ground to achieve the simultaneous shutdown of the positive and negative signals.

[0054] The above description is only a preferred embodiment of the present utility model and is not a limitation on the design of the present invention. Any equivalent changes made based on the key design of the present invention shall fall within the protection scope of the present invention.

Claims

1. A forward and reverse rotation module for a three-phase motor, characterized in that: It includes a forward rotation circuit and a reverse rotation circuit, and both the forward rotation circuit and the reverse rotation circuit include a delay circuit, an interlocking circuit, an optocoupler driving circuit and a switch circuit; the input end of the delay circuit is connected to the output end of the three-phase power supply, the interlocking circuit is connected to the delay circuit in parallel, the output end of the delay circuit is connected to the input end of the optocoupler driving circuit, the optocoupler driving circuit includes a light-emitting diode and two MOSFET tubes with a common source connected in reverse series, the output end of the optocoupler driving circuit is connected to the input end of the switch circuit to control the on and off of the switch circuit, and the output end of the switch circuit is connected to the input end of the three-phase motor, thereby forming a forward rotation path or a reverse rotation path.

2. A three-phase motor forward and reverse rotation module as claimed in claim 1, characterized in that: The switch circuit is composed of thyristors, and the drains of the two MOSFET tubes of the optocoupler drive circuit are respectively connected to the gates of the two thyristors.

3. A three-phase motor forward and reverse rotation module as claimed in claim 2, characterized in that: It also includes a first inductor and a seventh resistor, wherein the first inductor is connected between the output end of the optocoupler drive circuit and the gate of one of the thyristors, and the seventh resistor is connected between the output end of the optocoupler drive circuit and the gate of another thyristor.

4. A three-phase motor forward and reverse rotation module as claimed in claim 1, characterized in that: The delay circuit includes 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 to the forward signal input end or the reverse signal input end, the first diode is reversely connected in series 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 at both ends of the first diode, the positive terminal of the first capacitor is connected between the first diode and the second non-inverting buffer, the negative terminal of the first capacitor is grounded, and the output end of the second non-inverting buffer is connected to the input end of the optocoupler driving circuit.

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

6. A three-phase motor forward and reverse rotation module as claimed in claim 4, characterized in that: It also includes 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 transistor; the first voltage-stabilizing diode and the second voltage-stabilizing diode are connected in series in a forward direction, the positive terminal of the first voltage-stabilizing diode is grounded, 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 in series 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 forward signal input terminal or the reverse signal input terminal, the second capacitor and the fourth resistor are respectively connected in parallel at both ends of the first voltage-stabilizing diode, the output terminal of the second non-inverting buffer is connected in series with the fifth resistor and then connected to the base of the first NPN transistor, the third capacitor and the sixth resistor are respectively connected in parallel between the base and emitter of the first NPN transistor, the emitter of the first NPN transistor is grounded, and the collector of the first NPN transistor is connected to the input terminal of the optocoupler drive circuit.

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

9. A three-phase motor forward and reverse rotation module as claimed in claim 1, characterized in that: It also includes a step-down circuit, which includes a second NPN transistor, a first PNP transistor, and a second PNP transistor. The collector of the second NPN transistor is connected to the forward signal input terminal and the reverse signal input terminal, the base and emitter of the second NPN transistor are grounded respectively, the emitter of the first PNP transistor is connected to the forward signal input terminal and the reverse signal input terminal, 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 grounded.

10. A three-phase motor forward and reverse rotation module as claimed in claim 1, characterized in that: It also includes an RC protection circuit, which includes a capacitor, a resistor and a varistor. The capacitor and the resistor are connected in series and connected to both ends of the varistor. One end of the varistor is connected to any phase power supply of a three-phase power supply, and the other end of the varistor is connected to any input end of the three-phase motor.

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