Pure sine wave inverter with pulse width modulation, voltage stabilization and isolation functions

Abstract

The invention discloses a pure sine wave inverter with pulse width modulation, voltage stabilization and isolation functions. The pure sine wave inverter comprises a power input module, an input isolating module, a PWM modulation module, a transformation / rectification / filtering module, an SPWM driving module, an LC filtering module, a sine wave generator, an MCU and a voltage sampling module. The PWM modulation module comprises a time-base circuit chip, a twenty-first resistor, ..., a thirtieth resistor, a twenty-first capacitor, ..., a twenty-eighth capacitor, an eleventh diode, a twelfth diode, a thirteenth diode, an eleventh triode and a twelfth MOS tube. The voltage sampling module comprises a voltage comparing circuit. The voltage comparing circuit comprises a voltage comparator, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor and a first voltage stabilizing tube. The pure sine wave inverter can effectively isolate power input and furthermore has advantages of simple circuit structure, strong function, high flexibility in use, relatively wide application range, effective signal interference prevention, high accuracy of data acquired by an instrument, effective isolation between a control signal and a voltage sampling signal, and effective sampling precision improvement.

Description

technical field [0001] The invention relates to the field of inverters, in particular to a pure sine wave inverter with the function of pulse width modulation voltage stabilization and isolation. Background technique [0002] An inverter is a device that converts direct current into alternating current. At present, a modified sine wave inverter is used, which is composed of a low-voltage drive control circuit, a pulse width modulation output drive circuit, and an input-output protection circuit. However, this When the waveform generated by the modified sine wave inverter is used for precision instruments, there is no isolation and the signal interference is large, resulting in inaccurate data collection, especially in some medical equipment and military equipment, which have relatively high precision requirements , even a slight disturbance can have serious consequences. [0003] Pulse width modulation is an analog control method, which modulates the bias of the transistor ...

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Problems solved by technology

[0005] However, in the existing voltage sampling circuit, the voltage division method is usually used for sampling, and the variables to be sampled are directly sampled, and the control signal of the single-chip microcomputer is not effectively isolated from the voltage sampling signal, thereby affecting the control accuracy. The problem of large sampling errors

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