3 efficient and reliable low-cost PFC inverter designs

Probe domestic high frequency needle JKT-50L high frequency needle with 3 probes

7050 OSC seed vibration

Overview:
With the expansion of the demand for green energy in human society, inverter design has become the trend of the times. The efficient and reliable inverter system puts forward higher requirements for power factor correction and current harmonic suppression. For more details on the composition scheme of the 3 conventional inverters with power factor correction function (three-level composition scheme I, three-level composition scheme II and two-level composition scheme), please see this report...

1 The composition and structure of modern inverter power system With the development of control technologies and the improvement of operational performance in various industries, the electrical equipment in many industries is not directly using the AC power provided by the universal AC grid as an electric energy source, but through Various forms transform it to obtain the respective form of electrical energy required. The modern inverter system is a power supply system that realizes the inverter function through a combination circuit of rectification and inverter. In addition to the rectifier circuit and the inverter circuit, the inverter system also has a control circuit, a protection circuit, and an auxiliary circuit. The basic structure of modern inverter system is shown in Figure 1.
The functions of each part of the modern inverter system are as follows:
1. Rectifier circuit: The rectifier circuit converts AC power into DC power by using rectifier switching devices such as semiconductor diodes, thyristors (thyristors) and self-shutdown switching devices. In addition, the rectifier circuit should have a function to suppress current harmonics and power factor adjustment.
2. Inverter circuit: The function of the inverter circuit is to convert DC power into AC power, that is, by controlling the operating frequency and output time ratio of the inverter circuit, the frequency and amplitude of the output voltage or current of the inverter are in accordance with people's wishes. Or the requirements of the equipment work to change flexibly.
3. Control circuit: The function of the control circuit is to generate and adjust a series of control pulses to control the on and off of the inverter switch tube according to requirements, so as to complete the inverter function with the inverter main circuit.
4. Auxiliary circuit: The function of the auxiliary circuit is to convert the input voltage of the inverter into a DC voltage suitable for the operation of the control circuit. For the AC grid input, power frequency step-down, rectification, linear voltage regulation, etc. can be used. Of course, a DC-DC converter can also be used.
5. Protection circuit: The functions to be realized by the protection circuit mainly include: input overvoltage and undervoltage protection; output overvoltage and undervoltage protection; overload protection; overcurrent and short circuit protection; overheat protection.
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