What is the difference between sine wave inverter and ordinary inverter

1. Sine wave inverter input circuit
The input of the inverter is usually DC power, or DC power obtained by rectification and filtering of the mains power. These DC power include DC power obtained from the DC grid, batteries, photovoltaic cells and other methods. Usually, this power cannot be directly used as the input side voltage of the inverter. It is used as the input of the inverter after passing through a certain filter circuit and EMC circuit.

2. Inverter main circuit
The main circuit of the inverter is a power conversion circuit composed of power switching devices. There are many main circuit structural forms. Under different input and output conditions, the main circuit forms are also different. Each power conversion circuit has its advantages and disadvantages. , the most appropriate circuit topology should be considered as the main circuit structure in actual design.

3. Control circuit
According to the requirements of the inverter output, the control circuit generates one or more sets of pulse voltages through certain control technology, and acts on the power switch tubes through the drive circuit, so that the power switch tubes are turned on or off according to the specified order, and finally the main The required voltage waveform is obtained at the output of the circuit. The role of the control circuit is crucial to the inverter system. The performance of the control circuit directly determines the quality of the inverter output voltage waveform.

4. Output circuit
The output circuit generally includes an output filter circuit and an EMC circuit. If the output is DC, a rectifier circuit should be added later. For inverters with isolated output, there should also be an isolation transformer in the front stage of the output circuit. Depending on whether the output requires a voltage stabilizing circuit, the output circuit can be divided into open-loop and closed-loop control. The output of the open-loop system is only determined by the control circuit, while the output of the closed-loop system is also affected by the feedback loop, making the output more stable.

5. Auxiliary power supply
Certain parts or chips of the control circuit and input/output circuit have specific input voltage requirements, and the auxiliary power supply can meet the specific voltage requirements in the circuit. Usually, the auxiliary power supply consists of one or several DC-DC converters. For AC input, the auxiliary power supply is a combination of the rectified voltage and the DC-DC converter.

6. Protection circuit
Protection circuits usually include input overvoltage, undervoltage protection, output overvoltage, undervoltage protection, overload protection, overcurrent and short circuit protection. There are other protections for inverters working in specific situations, such as temperature protection in situations where the temperature is very low or very high, air pressure protection in the case of certain air pressure changes, and air pressure protection in humid environments. Humidity protection etc.

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