Constant voltage output detection control circuit of frequency converter

Abstract

The utility model relates to the technical field of frequency conversion control, and discloses a frequency converter constant voltage output detection control circuit which can be dynamically adjusted and controlled and is high in reliability, and the circuit comprises detection modules (210, 220, 230) used for obtaining at least one voltage signal output by a frequency converter, operational amplification modules (250, 260) and a master control module (MCU), the main control module (MCU) is used for receiving at least one input voltage signal after amplification processing and adjusting proportional gain and integral time according to the input voltage signal so as to realize closed-loop constant-voltage output of the frequency converter.

Description

A constant voltage output detection and control circuit for frequency converters Technical Field

[0001] This utility model relates to the field of frequency converter control technology, and more specifically, to a constant voltage output detection and control circuit for a frequency converter. Background Technology

[0002] Currently, constant voltage output control of frequency converters typically employs software VF (a design that physically or logically separates the motor control section (such as signal processing and algorithm adjustment) from the power section (voltage / current conversion)) algorithm control. However, the constant voltage performance of VF separation is highly dependent on parameter identification (such as stator resistance and load characteristics) and the accuracy of the control algorithm. In scenarios with large changes in input voltage or mutual inductance, its dynamic response is limited.

[0003] Therefore, how to achieve closed-loop constant voltage output by dynamically adjusting control parameters has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention Utility Model Content

[0004] The technical problem to be solved by this utility model is that, in view of the shortcomings of the existing VF separation constant voltage performance which is highly dependent on parameter identification (such as stator resistance, load characteristics) and control algorithm accuracy, and whose dynamic response is limited in scenarios with large changes in input voltage or mutual inductance, this utility model provides a frequency converter constant voltage output detection and control circuit that can dynamically adjust control and has high reliability.

[0005] The technical solution adopted by this utility model to solve its technical problem is: to construct a constant voltage output detection and control circuit for a frequency converter, which has the following features:

[0006] At least one detection module is configured within the constant voltage output detection and control circuit for acquiring at least one voltage signal output by the frequency converter;

[0007] At least one operational amplifier module, whose signal input terminal is connected to the output terminal of the detection module, is used to receive at least one of the voltage signals and amplify the voltage signals;

[0008] The main control module, whose signal input terminal is coupled to the signal output terminal of the operational amplifier module, is used to receive at least one of the voltage signals after amplification and to adjust the proportional gain and integral time according to the input voltage signal to achieve closed-loop constant voltage output of the frequency converter.

[0009] In some embodiments, the detection module includes a first detection module, a second detection module, and a third detection module.

[0010] One end of the first detection module is connected to the first phase output terminal of the frequency converter to acquire the first voltage signal.

[0011] One end of the second detection module is connected to the second phase output terminal of the frequency converter to acquire the second voltage signal.

[0012] One end of the third detection module is connected to the third phase output terminal of the frequency converter to acquire the third voltage signal.

[0013] The other ends of the first detection module, the second detection module, and the third detection module are respectively connected to the signal input terminal of the operational amplifier module.

[0014] In some embodiments, the operational amplification module includes a first operational amplification module and a second operational amplification module.

[0015] The first input terminal of the first operational amplifier module is connected to the other end of the first detection module.

[0016] The second input terminal of the first operational amplifier module is connected to the other end of the second detection module.

[0017] The third input terminal of the first operational amplifier module is connected to the other end of the third detection module.

[0018] One input terminal of the second operational amplifier module is connected to the first output terminal of the first operational amplifier module.

[0019] The second output terminal of the first operational amplifier module is connected to a signal input terminal of the main control module.

[0020] In some embodiments, the first operational amplifier module includes at least a first operational amplifier and a second operational amplifier.

[0021] The non-inverting input of the first operational amplifier is connected to the non-inverting input of the second operational amplifier.

[0022] The inverting input of the first operational amplifier is coupled to the other end of the first detection module.

[0023] The non-inverting inputs of the first operational amplifier and the second operational amplifier are respectively connected to the other end of the second detection module.

[0024] The inverting input of the second operational amplifier is coupled to the other end of the third detection module.

[0025] The first output terminal of the first operational amplifier is connected to an input terminal of the second operational amplifier module.

[0026] The second output terminal of the first operational amplifier module is connected to a signal input terminal of the main control module.

[0027] In some embodiments, the second operational amplifier module includes at least a third operational amplifier.

[0028] The inverting input of the third operational amplifier is connected to the output of the first operational amplifier via the twenty-second resistor.

[0029] The non-inverting input of the third operational amplifier is connected to the common terminal through the thirty-fourth resistor.

[0030] The output of the third operational amplifier is connected to another signal input of the main control module.

[0031] In some embodiments, a voltage divider module is also included, one end of which is connected to the non-inverting inputs of the first operational amplifier and the second operational amplifier.

[0032] The other end of the voltage divider module is connected to the common terminal.

[0033] In some embodiments, it also includes a first clamping diode, a second clamping diode, and a third clamping diode.

[0034] The first terminal of the first clamping diode is connected to one terminal of the first detection module.

[0035] The second terminal of the first clamping diode is connected to the positive terminal of the power supply.

[0036] The third terminal of the first clamping diode is connected to the negative terminal of the power supply.

[0037] The first terminal of the second clamping diode is connected to one terminal of the second detection module.

[0038] The second terminal of the second clamping diode is connected to the positive terminal of the power supply.

[0039] The third terminal of the second clamping diode is connected to the negative terminal of the power supply.

[0040] The first end of the third clamping diode is connected to one end of the third detection module.

[0041] The second terminal of the third clamping diode is connected to the positive terminal of the power supply.

[0042] The third terminal of the third clamping diode is connected to the negative terminal of the power supply.

[0043] In some implementations, a fourth clamping diode and a fifth clamping diode are also included.

[0044] The first terminal of the fourth clamping diode is connected to a signal input terminal of the main control module.

[0045] The first terminal of the fifth clamping diode is connected to another signal input terminal of the main control module.

[0046] The second terminal of the fourth clamping diode is connected to the positive terminal of the power supply.

[0047] The third terminal of the fourth clamping diode is connected to the negative terminal of the power supply.

[0048] The second terminal of the fifth clamping diode is connected to the positive terminal of the power supply.

[0049] The third terminal of the fifth clamping diode is connected to the negative terminal of the power supply.

[0050] The inverter constant voltage output detection and control circuit of this utility model includes a detection module for acquiring at least one voltage signal output by the inverter, an operational amplifier module, and a main control module. The main control module receives the at least one voltage signal after amplification and adjusts the proportional gain and integral time according to the input voltage signal to achieve closed-loop constant voltage output from the inverter. Compared with existing technologies, the main control module dynamically adjusts control parameters through feedback PI (proportional gain and integral time) to achieve closed-loop constant voltage output from the inverter. This effectively solves the problem that the constant voltage performance of VF separation is highly dependent on parameter identification (such as stator resistance and load characteristics) and the accuracy of the control algorithm, and its dynamic response is limited in scenarios with large changes in input voltage or mutual inductance. Attached Figure Description

[0051] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0052] Figure 1 is a circuit diagram of an embodiment of the inverter constant voltage output detection and control circuit provided by this utility model;

[0053] Figure 2 is a circuit diagram of another embodiment of the inverter constant voltage output detection and control circuit provided by this utility model. Detailed Implementation

[0054] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, the specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0055] As shown in Figures 1 and 2, in the first embodiment of the inverter constant voltage output detection and control circuit of this utility model, the inverter constant voltage output detection and control circuit (100 and 200) includes at least a power supply circuit 100 and a detection and amplification circuit 200.

[0056] The power supply circuit 100 serves as the 3-phase (corresponding to U / V / W) circuit output by the frequency converter, acting as the output terminal of the IGBT. The output 3-phase voltage (corresponding to U / V / W) is filtered to output voltage (corresponding to U1 / V1 / W1). The output voltage signal is then passed through an RC circuit composed of first resistor R1, first resistor R2, third resistor R3, first capacitor C1, fourth resistor R4, fifth resistor R5, sixth resistor R6, second capacitor C2, seventh resistor R7, eighth resistor R8, ninth resistor R9, and third capacitor C3 to absorb spike signals. This process stores energy in first inductor L1, second inductor L2, and third inductor L3 before providing power to the load.

[0057] The first RC circuit includes a first resistor R1, a second resistor R2, a third resistor R3, and a first capacitor C1.

[0058] The first resistor R1, the first resistor R2 and the third resistor R3 are connected in series and then connected in parallel with the first capacitor C1. One end of the first resistor R1 and the first capacitor C1 are connected in the U-phase circuit to absorb the spike signal in the U-phase circuit, and the other end is connected to the common terminal (corresponding to the EARTH terminal).

[0059] The second RC circuit includes a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, and a second capacitor C2.

[0060] The fourth resistor R4, the fifth resistor R5, and the sixth resistor R6 are connected in series and then connected in parallel with the second capacitor C2. One end of the fourth resistor R4 and the second capacitor C2 are connected in the U-phase circuit to absorb the spike signal in the V-phase circuit, and the other end is connected to the common terminal (corresponding to the EARTH terminal).

[0061] The third RC circuit includes the seventh resistor R7, the eighth resistor R8, the ninth resistor R9, and the third capacitor C3.

[0062] The seventh resistor R7, the eighth resistor R8, and the ninth resistor R9 are connected in series and then connected in parallel with the third capacitor C3. One end of the seventh resistor R7 and the third capacitor C3 are connected in the W phase circuit to absorb the spike signal in the V phase circuit, and the other end is connected to the common terminal (corresponding to the EARTH terminal).

[0063] The detection and amplification circuit 200 has the function of signal detection and amplification;

[0064] The detection and amplification circuit 200 includes at least one detection module (210, 220, 230), an operational amplifier module (250, 260), and a main control module MCU.

[0065] Among them, the detection modules (210, 220, 230) have the functions of signal (voltage / current) detection and current limiting;

[0066] The operational amplifier modules (250, 260) can amplify the input voltage signal and have high input resistance and zero-point drift suppression capability;

[0067] The main control module (MCU) performs logic operations and signal processing.

[0068] The main control module MCU also features fast response and elimination of steady-state error. During dynamic adjustment, the proportional (P) part can quickly respond to speed deviation, reduce dynamic speed drop, and accelerate system response speed; while the integral (I) part eliminates steady-state error by accumulating the integral value of the deviation, achieving zero steady-state error regulation.

[0069] When the actual speed deviates from the given value, the P part immediately generates an adjustment action proportional to the deviation, quickly suppressing speed fluctuations and reducing the maximum speed drop in the dynamic process;

[0070] The integral part (I) gradually increases the adjustment intensity over time by continuously accumulating the integral value of the deviation, so as to eliminate the steady-state error that the proportional adjustment cannot completely eliminate.

[0071] Specifically, the detection modules (210, 220, 230) are configured in the constant voltage output detection and control circuit to acquire at least one voltage signal (corresponding to U1 / V1 / W1) output by the frequency converter and output the acquired voltage signal (corresponding to U1 / V1 / W1) to the operational amplifier modules (250, 260).

[0072] Furthermore, the signal input terminal of at least one operational amplifier module (250, 260) is connected to the output terminal of the detection module (210, 220, 230) to receive at least one voltage signal (corresponding to U1 / V1 / W1), and amplify the voltage signal (corresponding to U1 / V1 / W1) to form a UUV-AD voltage signal and a UVW-AD voltage signal, and output the UUV-AD voltage signal and UVW-AD voltage signal to the main control module MCU;

[0073] Furthermore, the signal input terminal of the main control module MCU is coupled to the signal output terminal of the operational amplifier module (250, 260) to receive at least one UUV-AD voltage signal and UVW-AD voltage signal after amplification, and adjusts the proportional gain and integral time according to the input UUV-AD voltage signal or UVW-AD voltage signal to achieve closed-loop constant voltage output of the frequency converter.

[0074] Using this technical solution, the main control module MCU dynamically adjusts the control parameters through the feedback PI (proportional gain and integral time) to achieve closed-loop constant voltage output of the frequency converter. This can effectively solve the problem that the constant voltage performance of VF separation is highly dependent on parameter identification (such as stator resistance and load characteristics) and the accuracy of the control algorithm, and its dynamic response is limited in scenarios with large changes in input voltage or mutual inductance.

[0075] In some implementations, as shown in FIG2, in order to ensure the reliability of the voltage signal acquisition, a first detection module 210, a second detection module 220 and a third detection module 230 can be set in the detection modules (210, 220, 230). The above detection modules are used to detect the voltage signal output by the IGBT.

[0076] Specifically, one end of the first detection module 210 is connected to the first phase output terminal (corresponding to U1) of the frequency converter to acquire the first voltage signal.

[0077] One end of the second detection module 220 is connected to the second phase output terminal (corresponding to V1) of the frequency converter to acquire the second voltage signal.

[0078] One end of the third detection module 230 is connected to the third phase output terminal (corresponding to W1) of the frequency converter to acquire the third voltage signal.

[0079] The other ends of the first detection module 210, the second detection module 220 and the third detection module 230 are respectively connected to the signal input terminal of the operational amplifier module (corresponding to 250), and output the above voltage signals (corresponding to U1 / V1 / W1) to the operational amplifier module (corresponding to 250).

[0080] The first detection module 210 includes an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, an eighteenth resistor R18, and a nineteenth resistor R19 connected in series.

[0081] One end of the eleventh resistor R11 is connected to the first phase output terminal of the frequency converter (corresponding to U1) to obtain the first voltage signal, and one end of the nineteenth resistor R19 is connected to a signal input terminal of the operational amplifier module (corresponding to 250).

[0082] Furthermore, the second detection module 220 includes resistors R25 (twenty-fifth), R26 (twenty-sixth), R27 (twenty-seventh), R28 (twenty-eighth), R29 (twenty-ninth), R30 (thirtieth), R31 (thirtieth), R32 (thirtieth), and R33 (thirtieth) connected in series.

[0083] One end of the twenty-fifth resistor R25 is connected to the second phase output terminal (corresponding to V1) of the frequency converter to obtain the second voltage signal, and one end of the thirty-third resistor R33 is connected to a signal input terminal of the operational amplifier module (corresponding to 250).

[0084] Furthermore, the third detection module 230 includes resistors R38 (38th), R39 (39th), R40 (40th), R41 (41st), R42 (42nd), R43 (43rd), R44 (44th), R45 (45th), and R46 (46th) connected in series.

[0085] One end of the thirty-eighth resistor R38 is connected to the third phase output terminal (corresponding to W1) of the frequency converter to obtain the third voltage signal. One end of the forty-sixth resistor R46 is connected to a signal input terminal of the operational amplifier module (corresponding to 250).

[0086] In some implementations, as shown in Figure 2, in order to ensure the reliability of the output voltage signal, a first operational amplifier module 250 and a second operational amplifier module 260 can be provided in the operational amplifier modules (250, 260), which have the function of signal amplification;

[0087] Specifically, the first input terminal of the first operational amplifier module 250 is connected to the other end of the first detection module 210, and is used to receive the first voltage signal after being processed by the voltage divider of the first detection module 210.

[0088] The second input terminal of the first operational amplifier module 250 is connected to the other end of the second detection module 220, and is used to receive the second voltage signal after voltage division processing by the second detection module 220.

[0089] The third input terminal of the first operational amplifier module 250 is connected to the other end of the third detection module 230, and is used to receive the third voltage signal after voltage division processing by the third detection module 230.

[0090] An input terminal of the second operational amplifier module 260 is connected to the first output terminal of the first operational amplifier module 250.

[0091] The second output terminal of the first operational amplifier module 250 is connected to a signal input terminal of the main control module MCU, and the amplified UUV-AD voltage signal and UVW-AD voltage signal are input to the main control module MCU. The main control module MCU then adjusts the proportional gain and integral time according to the input voltage signal to achieve closed-loop constant voltage output of the frequency converter.

[0092] In some embodiments, as shown in FIG2, the first operational amplifier module 250 includes at least a first operational amplifier U1A and a second operational amplifier U1B.

[0093] In this configuration, the non-inverting input (pin 3) of the first operational amplifier U1A is connected to the non-inverting input (pin 3) of the second operational amplifier U1B.

[0094] The inverting input (corresponding to pin 2) of the first operational amplifier U1A is coupled to the other end of the first detection module 210.

[0095] The non-inverting input (pin 3) of the first operational amplifier U1A and the non-inverting input (pin 5) of the second operational amplifier U1B are respectively connected to the other end of the second detection module 220.

[0096] The inverting input (corresponding to pin 6) of the second operational amplifier U1B is coupled to the other end of the third detection module 230.

[0097] The first output terminal (corresponding to pin 1) of the first operational amplifier U1A is connected to an input terminal of the second operational amplifier module 260, and the amplified UUV-AD voltage signal is input to the second operational amplifier module 260.

[0098] The second output terminal (corresponding to pin 7) of the first operational amplifier module 250 is connected to a signal input terminal of the main control module MCU through the thirty-seventh resistor R37, and outputs the amplified UVW-AD voltage signal to the main control module MCU.

[0099] In some embodiments, as shown in FIG2, the second operational amplifier module 260 includes at least a third operational amplifier U2A.

[0100] Specifically, the inverting input (pin 2) of the third operational amplifier U2A is connected to the output (pin 1) of the first operational amplifier U1A through the twenty-second resistor R22.

[0101] The non-inverting input (corresponding to pin 3) of the third operational amplifier U2A is connected to the common terminal through the thirty-fourth resistor R34.

[0102] The output terminal (corresponding to pin 1) of the third operational amplifier U2A is connected to another signal input terminal of the main control module MCU through a series connection of resistors R23 (23), R36 (36), and R49 (49). The UUV-AD voltage signal after two-stage amplification is input to another signal input terminal of the main control module MCU through resistors R23 (23), R36 (36), and R49 (49).

[0103] That is, the voltage signals acquired by the first detection module 210, the second detection module 220 and the third detection module 230 are processed by the first operational amplifier U1A, the second operational amplifier U1B and the third operational amplifier U2A to obtain the UUV-AD voltage signal and the UVW-AD voltage signal, and the signal is output to the main control module MCU for control processing to achieve real-time adjustment of the voltage of the three phases U / V / W.

[0104] In some implementations, to ensure the reliability of the first operational amplifier module 250, a voltage divider module 240 can be provided in the control circuit. One end of the voltage divider module 240 is connected to the non-inverting input (pin 3) of the first operational amplifier U1A and the non-inverting input (pin 5) of the second operational amplifier U1B.

[0105] The other end of the voltage divider module 240 is connected to the common terminal.

[0106] The voltage divider module 240 includes a 35th resistor R35 and a 10th capacitor C10 connected in parallel. The 35th resistor R35 is a voltage divider resistor, and the 10th capacitor C10 is a filter capacitor.

[0107] Specifically, one end of the thirty-fifth resistor R35 and the tenth capacitor C10 is connected to the non-inverting input (pin 3) of the first operational amplifier U1A and the non-inverting input (pin 5) of the second operational amplifier U1B.

[0108] The other end of the thirty-fifth resistor R35 and the tenth capacitor C10 is connected to the common terminal.

[0109] In some implementations, as shown in FIG2, in order to prevent the first operational amplifier U1A and the second operational amplifier U1B from being damaged due to overvoltage, a first clamping diode D1, a second clamping diode D2 and a third clamping diode D3 can be provided in the control circuit to limit the potential at a certain point in the circuit and prevent the voltage from exceeding the preset range.

[0110] Specifically, the first terminal (corresponding to pin 3) of the first clamping diode D1 is connected to one end of the first detection module 210.

[0111] The second terminal (corresponding to pin 2) of the first clamping diode D1 is connected to the positive terminal of the power supply.

[0112] The third terminal (corresponding to pin 1) of the first clamping diode D1 is connected to the negative terminal of the power supply.

[0113] The first terminal (corresponding to pin 3) of the second clamping diode D2 is connected to one end of the second detection module 220.

[0114] The second terminal (corresponding to pin 2) of the second clamping diode D2 is connected to the positive terminal of the power supply.

[0115] The third terminal (corresponding to pin 1) of the second clamping diode D2 is connected to the negative terminal of the power supply.

[0116] The first terminal (corresponding to pin 3) of the third clamping diode D3 is connected to one end of the third detection module 230.

[0117] The second terminal (corresponding to pin 2) of the third clamping diode D3 is connected to the positive terminal of the power supply.

[0118] The third terminal (corresponding to pin 1) of the third clamping diode D3 is connected to the negative terminal of the power supply.

[0119] In some implementations, as shown in Figure 2, to prevent damage to the main control module MCU due to overvoltage, a fourth clamping diode D4 and a fifth clamping diode D5 can be installed in the control circuit.

[0120] Specifically, the first terminal (corresponding to pin 3) of the fourth clamping diode D4 is connected to a signal input terminal of the main control module MCU.

[0121] The first terminal (corresponding to pin 3) of the fifth clamping diode D5 is connected to another signal input terminal of the main control module MCU.

[0122] The second terminal (corresponding to pin 2) of the fourth clamping diode D4 is connected to the positive terminal of the power supply.

[0123] The third terminal (corresponding to pin 1) of the fourth clamping diode D4 is connected to the negative terminal of the power supply.

[0124] The second terminal (corresponding to pin 3) of the fifth clamping diode D5 is connected to the positive terminal of the power supply.

[0125] The third terminal (corresponding to pin 1) of the fifth clamping diode D5 is connected to the negative terminal of the power supply.

[0126] Using this technical solution, the output is adjusted by combining inductor energy storage filtering with sampling the real-time voltage of the U / V / W phases to achieve closed-loop control of constant voltage output.

[0127] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A constant voltage output detection and control circuit for a frequency converter, characterized in that, It comprises: at least one detection module configured within a constant voltage output detection and control circuit for acquiring at least one voltage signal output by the frequency converter; at least one operational amplifier module whose signal input terminal is connected to the output terminal of the detection module for receiving at least one voltage signal and amplifying the voltage signal; and a main control module whose signal input terminal is coupled to the signal output terminal of the operational amplifier module for receiving at least one voltage signal after amplification and adjusting the proportional gain and integral time according to the input voltage signal to achieve closed-loop constant voltage output of the frequency converter.

2. The inverter constant voltage output detection and control circuit according to claim 1, characterized in that, The detection module includes a first detection module, a second detection module, and a third detection module. One end of the first detection module is connected to the first phase output terminal of the frequency converter to acquire a first voltage signal. One end of the second detection module is connected to the second phase output terminal of the frequency converter to acquire a second voltage signal. One end of the third detection module is connected to the third phase output terminal of the frequency converter to acquire a third voltage signal. The other ends of the first detection module, the second detection module, and the third detection module are respectively connected to the signal input terminal of the operational amplifier module.

3. The inverter constant voltage output detection and control circuit according to claim 2, characterized in that, The operational amplifier module includes a first operational amplifier module and a second operational amplifier module. The first input terminal of the first operational amplifier module is connected to the other end of the first detection module. The second input terminal of the first operational amplifier module is connected to the other end of the second detection module. The third input terminal of the first operational amplifier module is connected to the other end of the third detection module. An input terminal of the second operational amplifier module is connected to the first output terminal of the first operational amplifier module. The second output terminal of the first operational amplifier module is connected to a signal input terminal of the main control module.

4. The inverter constant voltage output detection and control circuit according to claim 3, characterized in that, The first operational amplifier module includes at least a first operational amplifier and a second operational amplifier. The non-inverting input of the first operational amplifier is connected to the non-inverting input of the second operational amplifier. The inverting input of the first operational amplifier is coupled to the other end of the first detection module. The non-inverting inputs of the first operational amplifier and the second operational amplifier are respectively connected to the other end of the second detection module. The inverting input of the second operational amplifier is coupled to the other end of the third detection module. The first output terminal of the first operational amplifier is connected to an input terminal of the second operational amplifier module. The second output terminal of the first operational amplifier module is connected to a signal input terminal of the main control module.

5. The inverter constant voltage output detection and control circuit according to claim 4, characterized in that, The second operational amplifier module includes at least a third operational amplifier. The inverting input of the third operational amplifier is connected to the output of the first operational amplifier through a twenty-second resistor, the non-inverting input of the third operational amplifier is connected to the common terminal through a thirty-fourth resistor, and the output of the third operational amplifier is connected to another signal input terminal of the main control module.

6. The inverter constant voltage output detection and control circuit according to claim 4, characterized in that, It also includes a voltage divider module, one end of which is connected to the non-inverting inputs of the first operational amplifier and the second operational amplifier, and the other end of which is connected to a common terminal.

7. The inverter constant voltage output detection and control circuit according to claim 2, characterized in that, It also includes a first clamping diode, a second clamping diode, and a third clamping diode. The first terminal of the first clamping diode is connected to one end of the first detection module, the second terminal of the first clamping diode is connected to the positive terminal of the power supply, and the third terminal of the first clamping diode is connected to the negative terminal of the power supply. The first terminal of the second clamping diode is connected to one end of the second detection module, the second terminal of the second clamping diode is connected to the positive terminal of the power supply, and the third terminal of the second clamping diode is connected to the negative terminal of the power supply. The first terminal of the third clamping diode is connected to one end of the third detection module, the second terminal of the third clamping diode is connected to the positive terminal of the power supply, and the third terminal of the third clamping diode is connected to the negative terminal of the power supply.

8. The inverter constant voltage output detection and control circuit according to claim 2, characterized in that, It also includes a fourth clamping diode and a fifth clamping diode. The first end of the fourth clamping diode is connected to a signal input terminal of the main control module, the first end of the fifth clamping diode is connected to another signal input terminal of the main control module, the second end of the fourth clamping diode is connected to the positive terminal of the power supply, the third end of the fourth clamping diode is connected to the negative terminal of the power supply, the second end of the fifth clamping diode is connected to the positive terminal of the power supply, and the third end of the fifth clamping diode is connected to the negative terminal of the power supply.

Images