Amplification circuit, output circuit and pure chord voltage adjustable alternating current inverter power supply device

Abstract

The utility model relates to an amplifying circuit, an output circuit and a pure chord voltage adjustable alternating current inverter power supply device, and the amplifying circuit is applied to an inverter and is characterized by comprising a current conversion circuit and a power operational amplifier circuit; and one end of the current conversion circuit is connected with one end of the power operational amplifier circuit. The problems that when a high-power switching device works in a high-frequency on-off state, higher harmonics are likely to be generated, output noise is large, and normal work of equipment is not facilitated are solved.

Description

Technical Field

[0001] The present application relates to the field of AC power supply, and specifically to an amplifier circuit, an output circuit, and a pure sinusoidal voltage adjustable AC inverter power supply device. Background Art

[0002] Since most inverters on the market have fixed DC input and fixed AC output, they need DC input, adjustable output AC voltage, pure sine wave and other harsh environments and usage requirements.

[0003] Conventional inverters have a fixed DC input voltage and a fixed AC output voltage, and most of the square wave output is converted into a sine wave output through a sine wave filter. The waveform presents different output characteristics under different load types.

[0004] High-power switching devices operate in a high-frequency on-off state, which can easily generate high-order harmonics and high output noise, which is not conducive to the normal operation of the equipment. Utility Model Content

[0005] In view of the above problems, the purpose of the present application is to provide an amplifier circuit, an output circuit, and a pure sinusoidal voltage adjustable AC inverter power supply device.

[0006] According to a first aspect of an embodiment of the present application, an amplifier circuit is provided, which is applied to an inverter and includes: a current conversion circuit and a power operational amplifier circuit; one end of the current conversion circuit is connected to one end of the power operational amplifier circuit.

[0007] Furthermore, the power operational amplifier circuit includes a power amplifier circuit and a protection circuit; the power amplifier circuit includes one or more operational amplifier circuits; the several operational amplifier circuits are connected in parallel; one end of the power amplifier circuit is connected to the other end of the current conversion circuit; the other end of the power amplifier circuit is connected to one end of the protection circuit; the other end of the protection circuit is connected to one end of the boost circuit.

[0008] Furthermore, the current conversion circuit includes a power supply, a resistor R1, a resistor R3, a resistor R5 and an operational amplifier U2A; one end of the resistor R3 is connected to the other end of the digital-to-analog converter; the other end of the resistor R3 is connected to one end of the resistor R1 and the reverse input end of the operational amplifier U2A; one end of the resistor R5 is connected to the other end of the digital-to-analog converter; the other end of the resistor R5 is connected to the same-direction input end of the operational amplifier U2A; the output end of the operational amplifier U2A is connected to one end of the power operational amplifier circuit; the first interface and the second interface of the operational amplifier U2A are connected to the power supply.

[0009] Further, the operational amplifier circuit includes a power supply, a resistor R2, a resistor R4, a resistor R6, a resistor R7, a resistor R8, a resistor R9 and an operational amplifier U1; one end of the resistor R4 is connected to the other end of the current conversion circuit; the other end of the resistor R4 is connected to the same-direction input end of the operational amplifier U1; one end of the resistor R6 is grounded; the other end of the resistor R6 is connected to one end of the resistor R8, one end of the resistor R9, and the reverse input end of the operational amplifier U1; the other end of the resistor R8 is connected to the adjustable end of the resistor R7; both ends of the resistor R7 are connected to the power supply; the operational amplifier U1 pin VCC is connected to the power supply; the operational amplifier U1 pin Ilim is connected to one end of the resistor R2; the other end of the resistor R2 is grounded; the operational amplifier U1 pin VSS is connected to the power supply; the output end of the operational amplifier U1 is connected to the other end of the resistor R9 and one end of the protection circuit.

[0010] According to a second aspect of an embodiment of the present application, there is provided an output circuit applied to an inverter, comprising a boost circuit and any of the above-mentioned amplifier circuits.

[0011] According to the third aspect of the embodiment of the present application, a pure sinusoidal voltage adjustable AC inverter power supply device is provided, which is applied to an inverter, comprising: a generating circuit, an AC sampling circuit and the output circuit; one end of the generating circuit is connected to one end of the output circuit; the other end of the output circuit is connected to one end of the AC sampling circuit; the other end of the AC sampling circuit is connected to the other end of the generating circuit.

[0012] Furthermore, the generating circuit includes a high-performance micro-control unit processor and a digital-to-analog converter; one end of the high-performance micro-control unit processor is connected to one end of the digital-to-analog converter; the other end of the digital-to-analog converter is connected to one end of the amplifying circuit; the other end of the high-performance micro-control unit processor is connected to the other end of the AC sampling circuit.

[0013] Furthermore, the AC sampling circuit includes a miniature precision voltage transformer, a precision rectifier circuit, and an RC filter circuit; one end of the miniature precision voltage transformer is connected to the boost circuit; the other end of the miniature precision voltage transformer is connected to one end of the precision rectifier circuit; the other end of the precision rectifier circuit is connected to one end of the RC filter circuit.

[0014] Furthermore, the miniature precision voltage transformer includes resistor R12, resistor R15, resistor R200 and voltage mutual inductance PT1; one end of the resistor R12 is connected to interface 1 at the other end of the boost circuit; the other end of the resistor R12 is connected to one end of the resistor R15; the other end of the resistor R15 is connected to the first interface of the voltage mutual inductance PT1; the second interface of the voltage mutual inductance PT1 is connected to the interface at the other end of the boost circuit; the third interface of the voltage mutual inductance PT1 is connected to one end of the resistor R200 and one end of the precision rectifier circuit; the other end of the resistor R200 is grounded; the fourth interface of the voltage mutual inductance PT1 is grounded.

[0015] Further, the precision rectifier circuit includes a power supply, a resistor R20, a resistor R21, a resistor R22, a resistor R23, a resistor R24, a resistor R25, a resistor R26, an operational amplifier U4A, an operational amplifier U4B, a capacitor C1, a capacitor C2, a diode D1 and a diode D2; one end of the resistor R20 is connected to one end of the resistor R23 and the other end of the micro-precision voltage transformer; the other end of the resistor R20 is connected to one end of the resistor R22, one end of the diode D1 and the reverse input end of the operational amplifier U4A; the other end of the resistor R23 is connected to one end of the resistor R26, the other end of the resistor R24 ​​and the reverse input end of the operational amplifier U4B; one end of the resistor R21 is grounded; The other end of 21 is connected to the same-direction input end of the operational amplifier U4A; the first interface of the operational amplifier U4A is connected to the power supply and one end of the capacitor C1; the other end of the capacitor C1 is grounded; the second interface of the operational amplifier U4A is connected to the power supply and one end of the capacitor C2; the other end of the capacitor C2 is grounded; the output end of the operational amplifier U4A is connected to the other end of the diode D1 and one end of the diode D2; the other end of the diode D2 is connected to the other end of the resistor R22 and one end of the resistor R24; the same-direction input end of the operational amplifier U4B is connected to one end of the resistor R25; the other end of the resistor R25 is grounded; the output end of the operational amplifier U4B is connected to the other end of the resistor R26 and the RC filter circuit.

[0016] The technical solution provided by the embodiments of the present application may have the following beneficial effects:

[0017] The present application uses a current conversion circuit and a power operational amplifier circuit to replace a high-power switch device that generates high-order harmonics due to an incomplete periodic signal, thereby obtaining a low-noise, high-precision AC signal. The present application obtains a circuit that outputs stable, low-noise output in a high-frequency on-off state through the design of a current conversion circuit and a power operational amplifier circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate one or more embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0019] Figure 1 It is an output circuit diagram of an amplifier circuit, an output circuit, and a pure sinusoidal voltage adjustable AC inverter power supply device according to an exemplary embodiment;

[0020] Figure 2 The present invention is an AC sampling circuit diagram of an amplifier circuit, an output circuit, and a pure sinusoidal voltage adjustable AC inverter power supply device according to an exemplary embodiment. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the technical solutions in one or more embodiments of this specification, the following will be combined with the drawings in one or more embodiments of this specification to clearly and completely describe the technical solutions in one or more embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on one or more embodiments of this specification, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this document.

[0022] In the field of aviation 400HZ AC power supply, the DC input voltage range of the inverter power supply is wide, usually DC5V-DC60V. In the aviation field, there may be situations where only DC input can be provided, but AC power supply is required. Therefore, the inverter power supply device used in the aviation field needs to adapt to the wide DC input voltage range, that is, the inverter power supply device has high adaptability to voltage, and different levels of voltage can be applied within a certain range. At the same time, the inverter power supply device must also meet the requirements of harsh environments such as adjustable output AC voltage and pure sine wave. However, the inverter DC input voltage used in the prior art is fixed, the output AC voltage is fixed, and most of the square wave input is converted into a sine wave output by a sine wave filter device, which is not suitable for the aviation field. In addition, the inverter power supply device in the prior art uses a high-power switching device, which is easy to generate high-order harmonics and output noise in the high-frequency on-off state, while the aviation field requires a pure sine wave AC power supply that is not easy to generate noise.

[0023] Exemplary Devices

[0024] The embodiment of the present application provides an amplifier circuit, an output circuit, and a pure sinusoidal voltage adjustable AC inverter power supply device, which is applied to an inverter and includes: a generating circuit, an AC sampling circuit, and an output circuit. Figure 1 As shown, the AC sampling circuit is as follows Figure 2 shown.

[0025] The generating circuit includes a high performance microcontroller unit processor and a digital-to-analog converter;

[0026] One end of the high-performance microcontrol unit processor is connected to one end of the digital-to-analog converter; the other end of the digital-to-analog converter is connected to one end of the amplifier circuit; and the other end of the high-performance microcontrol unit processor is connected to the other end of the AC sampling circuit.

[0027] The high-performance microcontroller processor generates a DC sine wave digital quantity, and generates a sine wave function through the formula U=Umax*Sin(wt), where w=2πf, Umax is the voltage amplitude, and f is the frequency. The sine wave function is generated through the periodic change of the variable t. The digital-to-analog converter receives the digital quantity of the DC sine wave and outputs the DC sine wave analog quantity. It can be seen that the high-performance microcontroller processor can directly generate a pure sine wave without converting the square wave into a sine wave through a sine wave filter device to ensure the integrity of the sine wave waveform, thereby achieving the goal of not easily generating noise.

[0028] The output circuit is applied to the inverter and comprises a boost circuit and an amplifier circuit; one end of the amplifier circuit is connected to one end of the boost circuit.

[0029] The amplifier circuit is applied to an inverter and comprises a current conversion circuit and a power operational amplifier circuit. One end of the current conversion circuit is connected to one end of the power operational amplifier circuit.

[0030] The current conversion circuit includes a power supply, a resistor R1, a resistor R3, a resistor R5 and an operational amplifier U2A; one end of the resistor R3 is connected to the other end of the digital-to-analog converter (Sin, the digital-to-analog converter outputs a DC sine wave analog quantity); the other end of the resistor R3 is connected to one end of the resistor R1 and the reverse input end of the operational amplifier U2A; one end of the resistor R5 is connected to the other end of the digital-to-analog converter (Vrf, the reference voltage); the other end of the resistor R5 is connected to the same-direction input end of the operational amplifier U2A; the output end of the operational amplifier U2A is connected to one end of the power operational amplifier circuit; the first interface of the operational amplifier U2A (the No. 4 wiring of the operational amplifier U2A) and the second interface (the No. 8 wiring of the operational amplifier U2A) are connected to the power supply. In the embodiment of the present application, the power supply is 12V, the resistor R1, the resistor R3, the resistor R5 are 10K, and the operational amplifier U2A is TL082IDT.

[0031] The current conversion circuit converts the DC sinusoidal analog quantity with a complete waveform output by the generating circuit into a standard AC sinusoidal analog quantity. After receiving the pure sine wave, it is converted into AC power through the conversion circuit composed of the selected TL082IDT operational amplifier U2A. The circuit is simple and not easy to generate noise, which is convenient for the subsequent power operational amplifier circuit to perform power regulation on it.

[0032] The power operational amplifier circuit includes a power amplifier circuit and a protection circuit:

[0033] The power amplifier circuit includes one or more operational amplifier circuits, which are connected in parallel. One end of the power amplifier circuit is connected to the other end of the current conversion circuit, the other end of the power amplifier circuit is connected to one end of the protection circuit, and the other end of the protection circuit is connected to one end of the boost circuit. According to the preset AC signal, the power amplification factor is calculated to obtain the required number of operational amplifier circuits to form the power amplifier circuit.

[0034] The operational amplifier circuit includes a power supply, a resistor R2, a resistor R4, a resistor R6, a resistor R7, a resistor R8, a resistor R9 and an operational amplifier U1; one end of the resistor R4 is connected to the other end of the current conversion circuit; the other end of the resistor R4 is connected to the same-direction input end of the operational amplifier U1; one end of the resistor R6 is grounded; the other end of the resistor R6 is connected to one end of the resistor R8, one end of the resistor R9 and the reverse input end of the operational amplifier U1; the other end of the resistor R8 is connected to the adjustable end of the resistor R7; both ends of the resistor R7 are connected to the power supply; the pin VCC of the operational amplifier U1 is connected to the power supply; the pin Ilim of the operational amplifier U1 is connected to one end of the resistor R2; the other end of the resistor R2 is grounded; the pin VSS of the operational amplifier U1 is connected to the power supply; the output end of the operational amplifier U1 is connected to the other end of the resistor R9 and one end of the protection circuit. In the embodiment of the present application, the power supply is selected to be 28.5V, the resistor R2 is 1K, the resistor R4, the resistor R6 is 10K, the resistor R7 is 3269 / 100K, the resistor R8 is 1M, and the resistor R9 is 100K.

[0035] The power amplifier circuit increases the output power by multiples of the standard AC sinusoidal analog quantity, and the output power can be adjusted and controlled by controlling the number of operational amplifier circuits that constitute it. The circuit composition of the current conversion circuit and the power amplifier circuit composed of the operational amplifier is simple, and the components used are all small in size, light in weight, and can be board-compatible. There will be no harmonic noise in frequent switching, and it can be used to replace the existing high-power switching devices to avoid its large size, heavy weight, and non-board-compatible. When the working voltage is high, a higher peak voltage is generated during the high-frequency switching process, which is easy to generate high-order harmonics and large output noise.

[0036] The protection circuit includes a thermistor PTC 1, a varistor VDR 1 and a fuse FU 1; one end of the thermistor PTC 1 is connected to the other end of the power operational amplifier circuit; the other end of the thermistor PTC 1 is connected to one end of the varistor VDR 1 and one end of the fuse FU 1; the other end of the varistor VDR 1 is grounded and connected to an interface 2 at one end of the boost circuit; the other end of the fuse FU 1 is connected to an interface 1 at one end of the boost circuit.

[0037] The protection circuit is used to control the maximum value of the output current and prevent external voltage backflow.

[0038] In the embodiment of the present application, a high-performance, high-current output operational amplifier OPA548T is selected to amplify the AC input signal and output power. The operational amplifier can continuously output 3A and instantaneously output 5A current, and the output power is increased by multiples through the reasonable parallel connection of multiple operational amplifiers. The output has overcurrent and short-circuit protection functions. When the output current exceeds the maximum current of the operational amplifier or the output is short-circuited, the self-recovery fuse blows, effectively protecting the circuit from breakdown and damage. When the external interface is misconnected, resulting in voltage backflow, the varistor is activated to form a large circuit loop between FU1 and VDR1. At this time, the permanent fuse blows, effectively protecting the internal circuit from damage.

[0039] The boost circuit, composed of a boost transformer, is used to adjust the voltage as needed. Different ratio transformers can also be used to make controllable adjustments to the output voltage level to achieve an adjustable voltage output range.

[0040] The AC sampling circuit samples the switched AC signal to obtain a sampling signal.

[0041] The AC sampling circuit includes a micro precision voltage transformer, a precision rectifier circuit, and an RC filter circuit;

[0042] One end of the micro precision voltage transformer is connected to the other end of the boost circuit; the other end of the micro precision voltage transformer is connected to one end of the precision rectifier circuit; the other end of the precision rectifier circuit is connected to one end of the RC filter circuit; the other end of the RC filter circuit is connected to the other end of the high performance micro control unit processor.

[0043] The micro precision voltage transformer includes a resistor R12, a resistor R15, a resistor R200 and a voltage mutual inductance PT1; one end of the resistor R12 is connected to the interface 1 (interface 1 of J2) at the other end of the boost circuit; the other end of the resistor R12 is connected to one end of the resistor R15; the other end of the resistor R15 is connected to the first interface of the voltage mutual inductance PT1; the second interface of the voltage mutual inductance PT1 is connected to the interface 2 (interface 2 of J2) at the other end of the boost circuit; the third interface of the voltage mutual inductance PT1 is connected to one end of the resistor R200 and one end of the precision rectifier circuit; the other end of the resistor R200 is grounded; the fourth interface of the voltage mutual inductance PT1 is grounded. In the embodiment of the present application, the resistor R12 and the resistor R15 are selected to be 30K, the resistor R200 is 1K, and the voltage mutual inductance PT1 is SCT265F.

[0044] The precision rectifier circuit includes a power supply, a resistor R20, a resistor R21, a resistor R22, a resistor R23, a resistor R24, a resistor R25, a resistor R26, an operational amplifier U4A, an operational amplifier U4B, a capacitor C1, a capacitor C2, a diode D1 and a diode D2; one end of the resistor R20 is connected to one end of the resistor R23 and the other end of the micro-precision voltage transformer; the other end of the resistor R20 is connected to one end of the resistor R22, one end of the diode D1 and the reverse input end of the operational amplifier U4A; the other end of the resistor R23 is connected to one end of the resistor R26, the other end of the resistor R24 ​​and the reverse input end of the operational amplifier U4B; one end of the resistor R21 is grounded; the other end of the resistor R21 is connected to the operational amplifier U4 A is connected to the same-direction input terminal; the first interface of the operational amplifier U4A (wiring No. 4 of the operational amplifier U4A) is connected to the power supply and one end of the capacitor C1; the other end of the capacitor C1 is grounded; the second interface of the operational amplifier U4A (wiring No. 8 of the operational amplifier U4A) is connected to the power supply and one end of the capacitor C2; the other end of the capacitor C2 is grounded; the output terminal of the operational amplifier U4A is connected to the other end of the diode D1 and one end of the diode D2; the other end of the diode D2 is connected to the other end of the resistor R22 and one end of the resistor R24; the same-direction input terminal of the operational amplifier U4B is connected to one end of the resistor R25; the other end of the resistor R25 is grounded; the output terminal of the operational amplifier U4B is connected to the other end of the resistor R26 and the RC filtering circuit. In the embodiment of the present application, the power supply is selected to be 12V, the resistors R20, R21, R22, R23, R24, R25, and R26 are 10K, the operational amplifier U4A and the operational amplifier U4B are TL082IDT, and the capacitors C1 and C2 are 0.1uF / 50V.

[0045] The RC filter circuit includes a resistor R27, a resistor R28, a capacitor C6 and a capacitor C13. One end of the resistor R27 is connected to the precision rectifier circuit, and the other end of the resistor R27 is connected to the resistor R28 and the capacitor C6; the other end of the capacitor C6 is grounded; the other end of the resistor R28 is connected to one end of the capacitor C13; the other end of the capacitor C13 is grounded. In the embodiment of the present application, the resistor R27 is selected to be 10K, the resistor R28 is selected to be 100K, and the capacitors C6 and C13 are selected to be 0.1uF / 50V.

[0046] The collected AC signal is converted into a DC signal through a micro-precision voltage transformer, a precision rectifier circuit, and an RC filter circuit, and returned to a high-performance microcontroller processor, which determines whether the output signal meets the requirements. If not, the output signal is adjusted accordingly to meet the requirements. If it meets the requirements, the original output is maintained. The programmable power supply can be controlled by the controller, and the power supply accuracy can be adjusted.

[0047] The present application generates a pure sine wave through a high-performance microcontroller processor, and the waveform is complete. After the digital-to-analog converter input and output circuit, AC conversion and power adjustable amplification are performed in the output circuit. The output circuit is composed of operational amplifier related circuits, the circuit is simple, and it is not easy to generate high-order harmonics and noise in a high-frequency switching environment. The boost circuit outputs the adjusted AC signal after adjustable control of the output voltage according to the preset, and the AC sampling circuit samples and processes the adjusted AC signal, and returns the sampled and processed signal to the high-performance microcontroller processor to achieve real-time monitoring effect. The present application uses an operational amplifier circuit to replace high-power switching devices, avoiding the problems of large size, heavy weight and high cost of high-power switching devices. The circuit obtained is simple, small, light, can be board-based, and low cost. It can be realized that the programmable power supply can be controlled by the controller, the power supply accuracy can be adjusted, and the voltage output range can be adjusted. The output positive and negative poles can be physically connected and disconnected with the outside, the power supply power is large, and it can be adjusted according to the power supply requirements of the equipment.

[0048] The high-performance microcontroller processor receives the sampling signal obtained by the AC sampling circuit, and determines whether the sampling signal meets the preset standard. If not, it adjusts to generate the DC sine wave digital quantity, and if it meets, it maintains the original state.

[0049] The current conversion circuit receives the DC sine wave analog quantity and outputs an AC sine wave analog quantity. The power operational amplifier circuit receives the AC sine wave analog quantity and outputs an AC signal. The boost circuit receives the AC signal and outputs a regulated AC signal.

[0050] The power amplifier circuit receives the AC sine wave analog quantity, amplifies it, and outputs the AC signal through the protection circuit to obtain a low-noise, high-precision AC signal. The protection circuit is used to control the maximum value of the output current and prevent external voltage backflow.

[0051] The boost circuit connects the output of the operational amplifier to the boost transformer. The voltage input to the transformer side can be adjusted by adjusting the amplitude of the sine wave generated by the high-performance microcontroller processor. The transformer works in the boost state. By selecting transformers with different ratios, the output voltage level can be adjusted in a wide range of controllable ways.

[0052] The AC sampling circuit samples the adjusted AC signal to obtain a sampling signal. The AC sampling circuit includes a micro-precision voltage transformer, a precision rectifier circuit, and an RC filter circuit.

[0053] Through the micro-precision voltage transformer, precision rectification circuit and RC filtering circuit, the input 0-220V AC signal is converted into a DC 0-2.5V DC signal and sent to the ADC port of the high-performance micro-control unit processor for operation processing. This circuit does not need to occupy a large amount of CPU resources in the high-performance micro-control unit processor for sinusoidal wave periodic sampling. The AC signal is rectified into a DC signal through precision rectification and RC filtering circuit, effectively reducing the CPU processing task.

[0054] The high-performance microcontroller receives the sampling signal and determines whether the sampling signal meets the preset standard. If not, it adjusts and generates a DC sine wave digital quantity. If it meets, it maintains the original state.

[0055] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An amplifier circuit, applied to an inverter, characterized in that: include: A current conversion circuit and a power operational amplifier circuit; one end of the current conversion circuit is connected to one end of the power operational amplifier circuit.

2. The circuit according to claim 1, characterized in that The power operational amplifier circuit includes a power amplifier circuit and a protection circuit; The power amplifier circuit includes one or more operational amplifier circuits; the operational amplifier circuits are connected in parallel; one end of the power amplifier circuit is connected to the other end of the current conversion circuit; the other end of the power amplifier circuit is connected to one end of the protection circuit; the other end of the protection circuit is connected to one end of the boost circuit.

3. The circuit according to claim 1, characterized in that The current conversion circuit includes a power supply, a resistor R1, a resistor R3, a resistor R5 and an operational amplifier U2A; One end of the resistor R3 is connected to the other end of the digital-to-analog converter; the other end of the resistor R3 is connected to one end of the resistor R1 and the reverse input end of the operational amplifier U2A; one end of the resistor R5 is connected to the other end of the digital-to-analog converter; the other end of the resistor R5 is connected to the same-direction input end of the operational amplifier U2A; the output end of the operational amplifier U2A is connected to one end of the power operational amplifier circuit; the first interface and the second interface of the operational amplifier U2A are connected to the power supply.

4. The circuit according to claim 2, characterized in that The operational amplifier circuit includes a power supply, a resistor R2, a resistor R4, a resistor R6, a resistor R7, a resistor R8, a resistor R9 and an operational amplifier U1; One end of the resistor R4 is connected to the other end of the current conversion circuit; the other end of the resistor R4 is connected to the same-direction input end of the operational amplifier U1; one end of the resistor R6 is grounded; the other end of the resistor R6 is connected to one end of the resistor R8, one end of the resistor R9, and the reverse input end of the operational amplifier U1; the other end of the resistor R8 is connected to the adjustable end of the resistor R7; both ends of the resistor R7 are connected to the power supply; the pin VCC of the operational amplifier U1 is connected to the power supply; the pin Ilim of the operational amplifier U1 is connected to one end of the resistor R2; the other end of the resistor R2 is grounded; the pin VSS of the operational amplifier U1 is connected to the power supply; the output end of the operational amplifier U1 is connected to the other end of the resistor R9 and one end of the protection circuit.

5. An output circuit, applied to an inverter, characterized in that: It comprises a boost circuit and the amplifier circuit according to any one of claims 1 to 4.

6. A pure sinusoidal voltage adjustable AC inverter power supply device, applied to an inverter, characterized in that: include: A generating circuit, an AC sampling circuit and an output circuit as claimed in claim 5; One end of the generating circuit is connected to one end of the output circuit; the other end of the output circuit is connected to one end of the AC sampling circuit; the other end of the AC sampling circuit is connected to the other end of the generating circuit.

7. The device according to claim 6, characterized in that The generating circuit includes a high-performance microcontroller processor and a digital-to-analog converter; One end of the high-performance microcontroller processor is connected to one end of the digital-to-analog converter; the other end of the digital-to-analog converter is connected to one end of the amplifier circuit; the other end of the high-performance microcontroller processor is connected to the other end of the AC sampling circuit.

8. The device according to claim 6, characterized in that The AC sampling circuit includes a micro precision voltage transformer, a precision rectifier circuit, and an RC filter circuit; One end of the micro precision voltage transformer is connected to the boost circuit; the other end of the micro precision voltage transformer is connected to one end of the precision rectifier circuit; the other end of the precision rectifier circuit is connected to one end of the RC filter circuit.

9. The device according to claim 8, characterized in that The miniature precision voltage transformer includes a resistor R12, a resistor R15, a resistor R200 and a voltage transformer PT1; One end of the resistor R12 is connected to interface 1 at the other end of the boost circuit; the other end of the resistor R12 is connected to one end of the resistor R15; the other end of the resistor R15 is connected to the first interface of the voltage mutual inductance PT1; the second interface of the voltage mutual inductance PT1 is connected to the interface at the other end of the boost circuit; the third interface of the voltage mutual inductance PT1 is connected to one end of the resistor R200 and one end of the precision rectifier circuit; the other end of the resistor R200 is grounded; the fourth interface of the voltage mutual inductance PT1 is grounded.

10. The device according to claim 8, characterized in that The precision rectifier circuit includes a power supply, a resistor R20, a resistor R21, a resistor R22, a resistor R23, a resistor R24, a resistor R25, a resistor R26, an operational amplifier U4A, an operational amplifier U4B, a capacitor C1, a capacitor C2, a diode D1 and a diode D2; One end of the resistor R20 is connected to one end of the resistor R23 and the other end of the micro-precision voltage transformer; the other end of the resistor R20 is connected to one end of the resistor R22, one end of the diode D1 and the reverse input end of the operational amplifier U4A; the other end of the resistor R23 is connected to one end of the resistor R26, the other end of the resistor R24 ​​and the reverse input end of the operational amplifier U4B; one end of the resistor R21 is grounded; the other end of the resistor R21 is connected to the same-direction input end of the operational amplifier U4A; the first interface of the operational amplifier U4A is connected to the power supply and the capacitor C1 one end; the other end of the capacitor C1 is grounded; the second interface of the operational amplifier U4A is connected to the power supply and one end of the capacitor C2; the other end of the capacitor C2 is grounded; the output end of the operational amplifier U4A is connected to the other end of the diode D1 and one end of the diode D2; the other end of the diode D2 is connected to the other end of the resistor R22 and one end of the resistor R24; the same-direction input end of the operational amplifier U4B is connected to one end of the resistor R25; the other end of the resistor R25 is grounded; the output end of the operational amplifier U4B is connected to the other end of the resistor R26 and the RC filter circuit.

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