Inverter repair undervoltage fault treatment - Database & Sql Blog Articles

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GW MB10F 0.8A 1000V rectifier bridge

Photocoupler

In the maintenance of the inverter, we often hear overvoltage faults, but the undervoltage fault is also a problem often encountered in the use of the inverter. The reason is that the main circuit voltage is lower than the lower limit, the protection action or the rectifier bridge is damaged or the grid is instantaneously powered off, and the input is not equal.

The inverter after-sales personnel summarizes the method of undervoltage alarm detection voltage in the process of inverter undervoltage fault treatment, as follows:

Comparator detection

The voltage at one end of the comparator is fixed by a Zener diode, and the detected voltage is sampled and compared with it, and the result is output through the comparator.

2. ADC detection (analog/digital converter)

The detected voltage is sampled by the resistor and stepped down, and falls within the detectable range of the ADC. The alarm range of the voltage can be set by the program.

The storage capacitor in the main circuit has a great influence on the overvoltage and undervoltage of the inverter during operation. The various components of the inverter circuit have a certain service life, so once the inverter components reach the service life, it will cause a failure. Causes such as storage capacitors or other components in the main circuit may affect the main circuit, causing the entire inverter to malfunction. Usually, the inverter is out of service for too long, and for more than one year, a comprehensive physical examination should be performed for the storage capacitor.

How to avoid this phenomenon for inverters that are not used for a long time?

According to the requirements, the deactivated inverter should be energized every two or three months—times of 20 to 30 minutes. For electrolytic enamel containers that are not used for a long time, when the power is applied, the rated voltage is about 50%. As long as the pressure is between more than half an hour, the leakage current will drop and it can be used normally.

In addition, for inverters with a long service life (more than five years), it is also necessary to perform capacity detection on the energy storage capacitors. Frequent jump voltage faults during operation, most of which are DC capacitors with insufficient capacitor capacity, capacity loss or loss of capacity.