Causes and solutions for inverter overvoltage fault

Overvoltage fault occurs when the inverter is in the parking state. This fault may be caused by a variety of reasons, including too high power supply voltage, too short deceleration time, and failure of the voltage detection unit inside the inverter. The following will introduce these fault causes and corresponding solutions in detail to ensure the normal operation of the inverter.

1. Power supply voltage is too high

When the power supply voltage is too high, the DC bus voltage will exceed the rated value, causing the relay inside the inverter to energize, and then turn off the IGBT, causing the inverter to alarm and display an overvoltage fault. For this problem, the following measures can be taken:

Install a transformer or adjust the voltage regulator: Reduce the power supply voltage by adding a transformer or adjusting the voltage regulator to keep it within the normal range that the inverter can accept. This requires selecting a suitable transformer or voltage regulator according to the actual situation, and performing correct installation and debugging.

Check and replace wearing parts: For some equipment with a long service life or old equipment, the working status of wearing parts such as capacitors and transformers should be checked regularly, and damaged or degraded parts should be replaced in time to ensure the stable output of the power supply voltage.

2. Deceleration time is too short

When the motor deceleration time is too short, the motor is in the power generation state, and the feedback energy will cause the DC bus voltage to increase, thus causing an overvoltage fault. To solve this problem, the following measures can be taken:

Appropriately increase the deceleration time: By adjusting the parameter settings of the inverter, appropriately increase the motor's deceleration time so that the motor has enough time to feed back energy to the grid to avoid excessive bus voltage.

Choose an inverter with overvoltage protection function: When purchasing an inverter, you should choose a product with overvoltage protection function. This inverter can automatically shut down the IGBT when the power supply voltage is too high, thereby protecting the equipment from damage.

3. Failure of the voltage detection unit

If the voltage detection unit inside the inverter fails, it cannot correctly detect the voltage signal, causing the inverter to falsely report an overvoltage fault. In response to this situation, the following measures can be taken:

Replace damaged components or the entire module: When the components or modules in the voltage detection unit are damaged, the damaged parts should be replaced in time to restore the voltage detection function. This requires professional repair skills and tools, so it is recommended to contact professional technicians for repair.

Further troubleshoot the cause of the fault: If the problem persists after replacing the component or module, it may be due to other reasons. At this time, it is necessary to further investigate the cause of the fault, such as checking whether the inverter wiring is correct, whether there is electromagnetic interference, etc.

In addition to the above three common reasons, there are some other factors that may cause inverter overvoltage failure, such as contactor or relay failure, poor grounding, etc. For faults caused by these factors, corresponding measures can be taken to solve them. For example, when the contactor or relay fails, the damaged parts can be replaced; when the grounding is poor, the grounding system can be checked and improved, etc.