Types and selection of inverter filters

Categories: Industry news

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2021-05-17

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According to the application of the inverter filter, it can be divided into the following types:

LC filter: LC filter is suitable for occasions where the harmonic content is not high. A good LC filter can control the distortion rate and control the distortion rate to 8~10%;

Harmonic filter: Harmonic filter is suitable for occasions with high requirements on harmonics. Generally, the distortion rate can be controlled at 2~5%;

Sine wave filter: The sine wave filter combines the advantages of the reactor and the LC filter, which can integrate the waveform of the output end of the inverter into a standard sine wave, and can also solve the problem of long-distance transmission between the inverter and the load. The resulting voltage drop, etc.

Selection principle of inverter filter

1. Define the required working parameters

First, determine the rated working voltage, current and frequency of the equipment. When taking the rated current of the inverter filter, it cannot be taken too small, otherwise the inverter filter will be damaged or the life of the inverter filter will be reduced.

However, the rated current should not be too large, because the current will increase the volume of the inverter filter or reduce the electrical performance of the inverter filter. Generally, the rated current of the inverter filter is determined by 1.2~1.5 times of the rated current of the equipment.

2. Determine the appropriate type of inverter filter

In different occasions, the requirements for current or voltage distortion rate are different, and the corresponding inverter filter should be selected according to the requirements.

3. Identify the type of interference

According to the on-site interference source of the equipment, determine the type of interference noise, whether it is common mode interference or differential mode interference, and then select the frequency converter filter in a targeted manner.

If you encounter a situation where the type of interference cannot be determined, you can determine the filter type of the inverter through actual testing.

4. Leakage current

The inverter filter is selected according to the allowable value of the maximum leakage current of the equipment, especially for medical and health care equipment.