A dedicated leakage protection system for frequency converters

Abstract

This utility model relates to a leakage current protection system for frequency converters, including a first relay and a second relay. One end of the first relay is connected to the input voltage network of the frequency converter, and the other end is connected to the frequency converter via a first Hall current sensor. Its output end is electrically connected to the non-inverting input of a first comparator, and the output end of the first comparator is electrically connected to the control terminal of a first relay drive module. The output end of the first relay drive module is electrically connected to the coil of the first relay. One end of the second relay is connected to the output network, and the other end is connected to the frequency converter via a second Hall current sensor. Its output end is electrically connected to the non-inverting input of a second comparator, and the output end of the second comparator is electrically connected to the control terminal of a second relay drive module. The output end of the second relay drive module is electrically connected to the coil of the second relay. This utility model achieves leakage current protection by monitoring the current at the input and output terminals of the frequency converter and controlling the on / off state of the relays at the input and output terminals based on the current.

Description

[Technical Field]

[0001] This utility model relates to the field of frequency converter leakage protection technology, specifically a frequency converter-specific leakage protection system. [Background Technology]

[0002] The leakage protection technology of frequency converters is mainly to protect against the risk of overcurrent caused by leakage. However, existing frequency converter leakage protection devices mainly monitor the magnitude of the output current of the frequency converter to protect against leakage, but do not judge the magnitude of the input current of the frequency converter. Excessive input current of the frequency converter can also damage the frequency converter and bring safety hazards to the normal operation of the frequency converter. [Utility Model Content]

[0003] The purpose of this utility model is to address the aforementioned shortcomings by providing a dedicated leakage protection system for frequency converters. By monitoring the current at the input and output terminals of the frequency converter and controlling the on / off state of the relays at the input and output terminals based on the current, leakage protection for the frequency converter is achieved. This solves the technical problems in the prior art, such as the failure to judge the magnitude of the input current of the frequency converter, which poses a safety hazard to the normal operation of the frequency converter.

[0004] To achieve the above objectives, a dedicated leakage current protection system for frequency converters is designed, comprising a first Hall current sensor, a first comparator, a first relay, a second relay, a second Hall current sensor, a second comparator, a power supply module, a first relay drive module, and a second relay drive module. One end of the normally closed contact of the first relay is connected to the input voltage network of the frequency converter, and the other end of the normally closed contact of the first relay is electrically connected to the input terminal of the frequency converter via a first wire. The first wire passes through the magnetic core hole of the first Hall current sensor. The output terminal of the first Hall current sensor is electrically connected to the non-inverting input terminal of the first comparator. The output terminal of the first comparator is electrically connected to the control terminal of the first relay drive module. The output terminal of the first relay drive module is electrically connected to the coil of the first relay. The power supply module... The power supply module is electrically connected to the power input terminal of the first Hall current sensor, the input terminal of the first relay drive module, and the inverting input terminal of the first comparator, respectively. One end of the normally closed contact of the second relay is connected to the output power grid, and the other end of the normally closed contact of the second relay is electrically connected to the output terminal of the frequency converter through a second wire. The second wire passes through the magnetic core hole of the second Hall current sensor. The output terminal of the second Hall current sensor is electrically connected to the non-inverting input terminal of the second comparator. The output terminal of the second comparator is electrically connected to the control terminal of the second relay drive module. The output terminal of the second relay drive module is electrically connected to the coil of the second relay. The power supply module is electrically connected to the power input terminal of the second Hall current sensor, the input terminal of the second relay drive module, and the inverting input terminal of the second comparator, respectively.

[0005] Furthermore, it also includes a first Schmitt trigger and a second Schmitt trigger; the input terminal of the first Schmitt trigger is electrically connected to the output terminal of the first Hall current sensor, the output terminal of the first Schmitt trigger is electrically connected to the non-inverting input terminal of the first comparator, the input terminal of the second Schmitt trigger is electrically connected to the output terminal of the second Hall current sensor, and the output terminal of the second Schmitt trigger is electrically connected to the non-inverting input terminal of the second comparator. The power supply module is electrically connected to the power input terminals of the first Schmitt trigger and the second Schmitt trigger, respectively. By setting the Schmitt trigger, the limit voltage output by the Hall current sensor can be obtained, thereby improving the leakage current protection sensitivity.

[0006] Furthermore, it also includes a first voltage regulation module and a second voltage regulation module. The power supply module is electrically connected to the input terminals of the first voltage regulation module and the second voltage regulation module, respectively. The output terminal of the first voltage regulation module is electrically connected to the inverting input terminal of the first comparator, and the output terminal of the second voltage regulation module is electrically connected to the inverting input terminal of the second comparator. By setting the voltage regulation module, the reference voltage of the comparator can be adjusted through the voltage regulation module so that the protection system can be adapted to frequency converters with different rated currents.

[0007] Furthermore, the first comparator includes resistors R1 and R2 and an operational amplifier U1. The non-inverting input of the operational amplifier U1 is electrically connected to one end of resistor R1 and one end of resistor R2, respectively. The other end of resistor R1 is electrically connected to the output of the first Schmitt trigger. The other end of resistor R2 is electrically connected to the output of the operational amplifier U1. The inverting input of the operational amplifier U1 is electrically connected to the output of the first voltage regulation module. The output of the operational amplifier U1 is electrically connected to the control terminal of the first relay drive module. The positive terminal of the power input of the operational amplifier U1 is electrically connected to the power module, and the negative terminal of the power input of the operational amplifier U1 is grounded.

[0008] Furthermore, the second comparator includes an operational amplifier U2, a resistor R3, and a resistor R4. The non-inverting input of the operational amplifier U2 is electrically connected to the output of the second Schmitt trigger. The inverting input of the operational amplifier U2 is electrically connected to the output of the second voltage regulation module, one end of the resistor R3, and one end of the resistor R4. The power supply module is electrically connected to the other end of the resistor R3 and the positive terminal of the power input of the operational amplifier U2. The other end of the resistor R4 and the negative terminal of the power input of the operational amplifier U2 are both grounded.

[0009] Furthermore, both the first voltage regulation module and the second voltage regulation module include a resistor R5 and a variable resistor R6. The variable resistor R6 has a first fixed plate, a second fixed plate, and a moving plate. One end of the resistor R5 is electrically connected to the power supply module, and the other end of the resistor R5 is electrically connected to the first fixed plate and the moving plate of the variable resistor R6. The second fixed plate of the variable resistor R6 is grounded, and the moving plate of the variable resistor R6 is electrically connected to the inverting input terminal of operational amplifier U1 or operational amplifier U2. The two fixed plates of the variable resistor R6 are the two ends of the two variable resistors, and the moving plate is a movable terminal. When the moving plate moves, the resistance of the variable resistor R6 can be adjusted.

[0010] Furthermore, both the first and second relay drive modules include a switching circuit. The switching circuit includes a resistor R9, a transistor Q1, a resistor R12, a resistor R10, a MOSFET Q2, and a resistor R11. One end of the resistor R9 is electrically connected to the output terminal of operational amplifier U1 or operational amplifier U2, and the other end of the resistor R9 is electrically connected to the base of transistor Q1. One end of the resistor R12 is electrically connected to the power supply module, and the other end of the resistor R12 is electrically connected to the collector of transistor Q1. One end of the resistor R10 is electrically connected to the emitter of transistor Q1 and the gate of MOSFET Q2, respectively, and the other end of the resistor R10 is grounded. One end of the coil of the first or second relay is electrically connected to the power supply module, and the other end of the coil of the first or second relay is electrically connected to the drain of MOSFET Q2. The source of MOSFET Q2 is electrically connected to one end of resistor R11, and the other end of resistor R11 is grounded.

[0011] Furthermore, both the first relay drive module and the second relay drive module further include a signal amplification circuit. The signal amplification circuit includes resistors R7 and R8 and an operational amplifier U3. One end of resistor R7 is electrically connected to the output terminal of operational amplifier U1 or the output terminal of operational amplifier U2. The non-inverting input terminal of operational amplifier U3 is electrically connected to the other end of resistor R7 and one end of resistor R8, respectively. The other end of resistor R8 is electrically connected to the output terminal of operational amplifier U3. The inverting input terminal of operational amplifier U3 is grounded. The output terminal of operational amplifier U3 is electrically connected to one end of resistor R9.

[0012] Furthermore, both the first relay drive module and the second relay drive module further include a filter circuit. The filter circuit includes a capacitor C1 and a Zener diode D1. One end of the capacitor C1 is electrically connected to one end of the resistor R11, and the other end of the capacitor C1 is grounded. The positive terminal of the Zener diode D1 is grounded, and the negative terminal of the Zener diode D1 is electrically connected to the drain of the MOSFET Q2.

[0013] Furthermore, both the first relay drive module and the second relay drive module also include an indicator light circuit. The indicator light circuit includes a resistor R13 and a light-emitting diode D2. One end of the resistor R13 is electrically connected to the power supply module, and the other end of the resistor R13 is electrically connected to the positive terminal of the light-emitting diode D2. The negative terminal of the light-emitting diode D2 is electrically connected to one end of the coil of the first relay or the second relay.

[0014] Compared with the prior art, this invention uses two Hall current sensors to monitor the current at the input and output terminals of the frequency converter, respectively. The voltages output by these two sensors control two relays at the input and output terminals of the frequency converter. When the input current of the frequency converter is too high, the output voltage of the first Hall current sensor exceeds the first reference voltage VREF-1 at the inverting input terminal of the first comparator. The first comparator then outputs a high level, which controls the first relay drive module to connect the coil of the first relay to the power supply module. This energizes the coil of the first relay, opening its normally closed contact and thus cutting off the input current of the frequency converter. When the output current of the frequency converter is too high... When the output voltage of the second Hall current sensor is greater than the second reference voltage VREF-2 at the inverting input terminal of the second comparator, the second comparator outputs a high level. The high level output of the second comparator controls the second relay drive module to connect the coil of the second relay to the power supply module. The coil of the second relay is energized, and the normally closed contact of the second relay opens, thereby cutting off the current output by the frequency converter. In summary, this utility model monitors the current at the input and output terminals of the frequency converter and controls the on / off state of the relays at the input and output terminals based on the current, thereby achieving leakage protection for the frequency converter. This solves the technical problems in the prior art, such as the lack of judgment on the magnitude of the input current of the frequency converter, which brings safety hazards to the normal operation of the frequency converter. [Image Description]

[0015] Figure 1 The circuit principle block of this utility model Figure 1 ;

[0016] Figure 2 The circuit principle block of this utility model Figure 2 ;

[0017] Figure 3 The circuit principle block of this utility model Figure 3 ;

[0018] Figure 4 This is a circuit diagram of the first comparator in an embodiment of the present invention;

[0019] Figure 5This is a circuit diagram of the second comparator in an embodiment of the present invention;

[0020] Figure 6 This is a circuit diagram of the first voltage regulation module or the second voltage regulation module in an embodiment of this utility model;

[0021] Figure 7 This is a circuit diagram of the first relay drive module or the second relay drive module in the embodiments of this utility model. [Detailed Implementation]

[0022] The present invention will be further described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention:

[0023] like Figure 1 As shown, this embodiment provides a dedicated leakage current protection system for frequency converters, including a first Hall current sensor, a first comparator, a first relay, a second relay, a second Hall current sensor, a second comparator, a power supply module, a first relay drive module, and a second relay drive module. One end of the normally closed contact of the first relay is used to connect to the input voltage network of the frequency converter, and the other end of the normally closed contact of the first relay is electrically connected to the input terminal of the frequency converter through a first wire. The first wire passes through the magnetic core hole of the first Hall current sensor. The output terminal of the first Hall current sensor is electrically connected to the non-inverting input terminal of the first comparator. The output terminal of the first comparator is electrically connected to the control terminal of the first relay drive module. The output terminal of the first relay drive module is electrically connected to the coil of the first relay. The power supply module is electrically connected to the power input terminal of the first Hall current sensor, the input terminal of the first relay drive module, and the inverting input terminal of the first comparator, respectively. One end of the normally closed contact of the second relay is used to connect to the output power grid, and the other end of the normally closed contact of the second relay is electrically connected to the output terminal of the frequency converter through a second wire. The second wire passes through the magnetic core hole of the second Hall current sensor. The output terminal of the second Hall current sensor is electrically connected to the non-inverting input terminal of the second comparator. The output terminal of the second comparator is electrically connected to the control terminal of the second relay drive module. The output terminal of the second relay drive module is electrically connected to the coil of the second relay. The power supply module is electrically connected to the power input terminal of the second Hall current sensor, the input terminal of the second relay drive module, and the inverting input terminal of the second comparator, respectively. Specifically, the power supply module can be a multi-output power chip, and the power supply module can output a DC voltage of 1.5V-24V; among which, the 24V DC voltage is used to drive the coil of the relay for excitation.

[0024] like Figure 2As shown, the aforementioned leakage current protection system further includes a first Schmitt trigger and a second Schmitt trigger; the input terminal of the first Schmitt trigger is electrically connected to the output terminal of the first Hall current sensor, and the output terminal of the first Schmitt trigger is electrically connected to the non-inverting input terminal of the first comparator; the input terminal of the second Schmitt trigger is electrically connected to the output terminal of the second Hall current sensor, and the output terminal of the second Schmitt trigger is electrically connected to the non-inverting input terminal of the second comparator; the power supply module is electrically connected to the power input terminals of the first Schmitt trigger and the second Schmitt trigger, respectively; by setting the Schmitt trigger, the limit voltage output by the Hall current sensor can be obtained, thereby improving the leakage current protection sensitivity.

[0025] like Figure 3 As shown, the aforementioned leakage current protection system also includes two voltage regulation modules (a first voltage regulation module and a second voltage regulation module). The power supply module is electrically connected to the input terminals of the first voltage regulation module and the second voltage regulation module, respectively. The output terminal of the first voltage regulation module is electrically connected to the inverting input terminal of the first comparator, and the output terminal of the second voltage regulation module is electrically connected to the inverting input terminal of the second comparator. By setting up the voltage regulation modules, the reference voltage of the comparator can be adjusted through the voltage regulation modules, so that the protection system can be adapted to frequency converters with different rated currents.

[0026] like Figure 4 As shown, the first comparator includes resistors R1 and R2 and operational amplifier U1. The non-inverting input of operational amplifier U1 is electrically connected to one end of resistor R1 and one end of resistor R2, respectively. The other end of resistor R1 is electrically connected to the output of the first Schmitt trigger, and the other end of resistor R2 is electrically connected to the output of operational amplifier U1. The inverting input of operational amplifier U1 is electrically connected to the output of the first voltage regulation module. The output of operational amplifier U1 is electrically connected to the control terminal of the first relay drive module. The positive terminal of the power input of operational amplifier U1 is electrically connected to the power module, and the negative terminal of the power input of operational amplifier U1 is grounded.

[0027] like Figure 5 As shown, the second comparator includes an operational amplifier U2, a resistor R3, and a resistor R4. The non-inverting input of the operational amplifier U2 is electrically connected to the output of the second Schmitt trigger. The inverting input of the operational amplifier U2 is electrically connected to the output of the second voltage regulation module, one end of the resistor R3, and one end of the resistor R4. The power supply module is electrically connected to the other end of the resistor R3 and the positive terminal of the power supply input of the operational amplifier U2. The other end of the resistor R4 and the negative terminal of the power supply input of the operational amplifier U2 are both grounded.

[0028] like Figure 6As shown, the voltage regulation module (first voltage regulation module or second voltage regulation module) includes a resistor R5 and a variable resistor R6. The variable resistor R6 has a first fixed plate, a second fixed plate, and a moving plate. One end of the resistor R5 is electrically connected to the power supply module, and the other end of the resistor R5 is electrically connected to the first fixed plate and the moving plate of the variable resistor R6. The second fixed plate of the variable resistor R6 is grounded, and the moving plate of the variable resistor R6 is electrically connected to the inverting input terminal of operational amplifier U1 or operational amplifier U2. The two fixed plates of the variable resistor R6 are the two ends of the two variable resistors, and the moving plate is a movable terminal. When the moving plate moves, the resistance of the variable resistor R6 can be adjusted.

[0029] like Figure 7 As shown, the relay drive module (first relay drive module or second relay drive module) includes a switching circuit, a signal amplification circuit, a filtering circuit, and an indicator light circuit. The switching circuit includes resistor R9, transistor Q1, resistor R12, resistor R10, MOSFET Q2, and resistor R11. One end of resistor R9 is electrically connected to the output of operational amplifier U1 or operational amplifier U2, and the other end of resistor R9 is electrically connected to the base of transistor Q1. One end of resistor R12 is electrically connected to the power supply module, and the other end of resistor R12 is electrically connected to the collector of transistor Q1. One end of resistor R10 is electrically connected to the emitter of transistor Q1 and the gate of MOSFET Q2, respectively, and the other end of resistor R10 is grounded. One end of the coil of the first relay or the second relay is electrically connected to the power supply module, and the other end of the coil of the first relay or the second relay is electrically connected to the drain of MOSFET Q2. The source of MOSFET Q2 is electrically connected to one end of resistor R11, and the other end of resistor R11 is grounded.

[0030] Specifically, the signal amplification circuit includes resistors R7 and R8, and operational amplifier U3. One end of resistor R7 is electrically connected to the output of operational amplifier U1 or U2. The non-inverting input of operational amplifier U3 is electrically connected to the other end of resistor R7 and one end of resistor R8, respectively. The other end of resistor R8 is electrically connected to the output of operational amplifier U3. The inverting input of operational amplifier U3 is grounded, and the output of operational amplifier U3 is electrically connected to one end of resistor R9. The filter circuit includes capacitor C1 and Zener diode D1. One end of capacitor C1 is electrically connected to one end of resistor R11, and the other end of capacitor C1 is grounded. The positive terminal of Zener diode D1 is grounded, and the negative terminal of Zener diode D1 is electrically connected to the drain of MOSFET Q2. The relay drive module also includes an indicator light circuit, which includes resistor R13 and LED D2. One end of resistor R13 is electrically connected to the power supply module, and the other end of resistor R13 is electrically connected to the positive terminal of LED D2. The negative terminal of LED D2 is electrically connected to one end of the coil of the first or second relay.

[0031] When the comparator outputs a high-level signal, the high-level signal is amplified by the signal amplification circuit and then drives transistor Q1 to conduct. After transistor Q1 conducts, the voltage divider across resistor R10 drives MOSFET Q2 to conduct. After MOSFET Q2 conducts, the coil KA of the first or second relay is energized and magnetized. The normally closed contact of the first or second relay is attracted by the magnetized coil, and the normally closed contact of the first or second relay opens, thus realizing the leakage protection of the frequency converter.

[0032] It should be noted that the electrical connection in this utility model refers to the connection made by means of a wire or conductor, so that the electrical components at both ends of the wire or conductor can conduct current.

[0033] This embodiment of the invention uses two Hall current sensors. When leakage current occurs in the frequency converter (short circuit at the input or output terminal), the two Hall current sensors monitor the current at the input and output terminals of the frequency converter, respectively, and use the voltage outputs of the two Hall current sensors to control two relays at the input and output terminals of the frequency converter. When the current at the input terminal of the frequency converter is too large, when the output voltage of the first Hall current sensor is greater than the first reference voltage VREF-1 at the inverting input terminal of the first comparator, the first comparator outputs a high level, which controls the first relay drive module. When the coil of the first relay is connected to the power module, the coil of the first relay is energized, and the normally closed contact of the first relay opens, thereby cutting off the input current of the frequency converter. When the output current of the frequency converter is too large, when the output voltage of the second Hall current sensor is greater than the second reference voltage VREF-2 at the inverting input of the second comparator, the second comparator outputs a high level. The high level output of the second comparator controls the second relay drive module to connect the coil of the second relay to the power module, energizing the coil of the second relay and opening the normally closed contact of the second relay, thereby cutting off the current output by the frequency converter. This utility model monitors the current at the input and output terminals of the frequency converter and controls the on / off state of the relays at the input and output terminals based on the current, thereby achieving leakage current protection for the frequency converter.

[0034] In summary, this utility model includes two Hall current sensors, two comparators, a first relay, a second relay, two Hall current sensors, a power supply module, and two relay drive modules. When the input current of the frequency converter is too high, the high-level output of the comparator at the input end controls the first relay drive module to connect the coil of the first relay to the power supply module, energizing the coil of the first relay and cutting off the input current of the frequency converter. When the output current of the frequency converter is too high, the high-level output of the comparator at the output end controls the second relay drive module to connect the coil of the second relay to the power supply module, cutting off the current output by the frequency converter. This utility model monitors the current at the input and output ends of the frequency converter and controls the on / off state of the relays at the input and output ends based on the current at the input and output ends, thereby achieving leakage protection for the frequency converter.

[0035] This utility model is not limited to the above-described embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of this utility model shall be considered equivalent substitutions and shall be included within the protection scope of this utility model.

Claims

1. A leakage current protection system specifically for frequency converters, characterized in that: It includes a first Hall current sensor, a first comparator, a first relay, a second relay, a second Hall current sensor, a second comparator, a power supply module, a first relay drive module, and a second relay drive module; One end of the normally closed contact of the first relay is connected to the input voltage network of the frequency converter, and the other end of the normally closed contact of the first relay is electrically connected to the input terminal of the frequency converter through a first wire. The first wire passes through the magnetic core hole of the first Hall current sensor. The output terminal of the first Hall current sensor is electrically connected to the non-inverting input terminal of the first comparator. The output terminal of the first comparator is electrically connected to the control terminal of the first relay drive module. The output terminal of the first relay drive module is electrically connected to the coil of the first relay. The power supply module is electrically connected to the power input terminal of the first Hall current sensor, the input terminal of the first relay drive module, and the inverting input terminal of the first comparator, respectively. One end of the normally closed contact of the second relay is connected to the output power grid, and the other end of the normally closed contact of the second relay is electrically connected to the output terminal of the frequency converter through a second wire. The second wire passes through the magnetic core hole of the second Hall current sensor. The output terminal of the second Hall current sensor is electrically connected to the non-inverting input terminal of the second comparator. The output terminal of the second comparator is electrically connected to the control terminal of the second relay drive module. The output terminal of the second relay drive module is electrically connected to the coil of the second relay. The power supply module is electrically connected to the power input terminal of the second Hall current sensor, the input terminal of the second relay drive module, and the inverting input terminal of the second comparator, respectively.

2. The inverter-specific leakage protection system as described in claim 1, characterized in that: It also includes a first Schmitt trigger and a second Schmitt trigger; the input terminal of the first Schmitt trigger is electrically connected to the output terminal of the first Hall current sensor, the output terminal of the first Schmitt trigger is electrically connected to the non-inverting input terminal of the first comparator, the input terminal of the second Schmitt trigger is electrically connected to the output terminal of the second Hall current sensor, the output terminal of the second Schmitt trigger is electrically connected to the non-inverting input terminal of the second comparator, and the power supply module is electrically connected to the power input terminals of the first Schmitt trigger and the second Schmitt trigger, respectively.

3. The inverter-specific leakage protection system as described in claim 2, characterized in that: It also includes a first voltage regulation module and a second voltage regulation module. The power supply module is electrically connected to the input terminals of the first voltage regulation module and the second voltage regulation module, respectively. The output terminal of the first voltage regulation module is electrically connected to the inverting input terminal of the first comparator, and the output terminal of the second voltage regulation module is electrically connected to the inverting input terminal of the second comparator.

4. The inverter-specific leakage protection system as described in claim 3, characterized in that: The first comparator includes resistors R1 and R2 and an operational amplifier U1. The non-inverting input of the operational amplifier U1 is electrically connected to one end of resistor R1 and one end of resistor R2, respectively. The other end of resistor R1 is electrically connected to the output of a first Schmitt trigger. The other end of resistor R2 is electrically connected to the output of operational amplifier U1. The inverting input of operational amplifier U1 is electrically connected to the output of a first voltage regulation module. The output of operational amplifier U1 is electrically connected to the control terminal of a first relay drive module. The positive terminal of the power input of operational amplifier U1 is electrically connected to a power module, and the negative terminal of the power input of operational amplifier U1 is grounded.

5. The inverter-specific leakage protection system as described in claim 4, characterized in that: The second comparator includes an operational amplifier U2, a resistor R3, and a resistor R4. The non-inverting input of the operational amplifier U2 is electrically connected to the output of the second Schmitt trigger. The inverting input of the operational amplifier U2 is electrically connected to the output of the second voltage regulation module, one end of the resistor R3, and one end of the resistor R4. The power supply module is electrically connected to the other end of the resistor R3 and the positive terminal of the power input of the operational amplifier U2. The other end of the resistor R4 and the negative terminal of the power input of the operational amplifier U2 are both grounded.

6. The inverter-specific leakage protection system as described in claim 5, characterized in that: Both the first voltage regulation module and the second voltage regulation module include a resistor R5 and a variable resistor R6. The variable resistor R6 has a first fixed plate, a second fixed plate, and a moving plate. One end of the resistor R5 is electrically connected to the power supply module, and the other end of the resistor R5 is electrically connected to the first fixed plate and the moving plate of the variable resistor R6. The second fixed plate of the variable resistor R6 is grounded, and the moving plate of the variable resistor R6 is electrically connected to the inverting input terminal of operational amplifier U1 or operational amplifier U2.

7. The inverter-specific leakage protection system as described in claim 5, characterized in that: Both the first and second relay drive modules include a switching circuit. The switching circuit includes a resistor R9, a transistor Q1, a resistor R12, a resistor R10, a MOSFET Q2, and a resistor R11. One end of the resistor R9 is electrically connected to the output terminal of operational amplifier U1 or operational amplifier U2, and the other end of the resistor R9 is electrically connected to the base of transistor Q1. One end of the resistor R12 is electrically connected to the power supply module, and the other end of the resistor R12 is electrically connected to the collector of transistor Q1. One end of the resistor R10 is electrically connected to the emitter of transistor Q1 and the gate of MOSFET Q2, and the other end of the resistor R10 is grounded. One end of the coil of the first or second relay is electrically connected to the power supply module, and the other end of the coil of the first or second relay is electrically connected to the drain of MOSFET Q2. The source of MOSFET Q2 is electrically connected to one end of resistor R11, and the other end of resistor R11 is grounded.

8. The frequency converter-specific leakage protection system as described in claim 7, characterized in that: Both the first relay drive module and the second relay drive module further include a signal amplification circuit. The signal amplification circuit includes resistors R7 and R8 and operational amplifier U3. One end of resistor R7 is electrically connected to the output terminal of operational amplifier U1 or the output terminal of operational amplifier U2. The non-inverting input terminal of operational amplifier U3 is electrically connected to the other end of resistor R7 and one end of resistor R8, respectively. The other end of resistor R8 is electrically connected to the output terminal of operational amplifier U3. The inverting input terminal of operational amplifier U3 is grounded. The output terminal of operational amplifier U3 is electrically connected to one end of resistor R9.

9. The frequency converter-specific leakage protection system as described in claim 8, characterized in that: Both the first relay drive module and the second relay drive module further include a filter circuit. The filter circuit includes a capacitor C1 and a Zener diode D1. One end of the capacitor C1 is electrically connected to one end of the resistor R11, and the other end of the capacitor C1 is grounded. The positive terminal of the Zener diode D1 is grounded, and the negative terminal of the Zener diode D1 is electrically connected to the drain of the MOSFET Q2.

10. The inverter-specific leakage protection system as described in claim 9, characterized in that: Both the first relay drive module and the second relay drive module further include an indicator light circuit. The indicator light circuit includes a resistor R13 and a light-emitting diode D2. One end of the resistor R13 is electrically connected to the power supply module, and the other end of the resistor R13 is electrically connected to the positive terminal of the light-emitting diode D2. The negative terminal of the light-emitting diode D2 is electrically connected to one end of the coil of the first relay or the second relay.

Images