Repairing inverter requires wide knowledge and strong professionalism, and the maintenance personnel should not only have a certain theoretical foundation, but also a lot of practical experience. The following Everest maintenance master has introduced us 2 practical methods to repair inverter quickly.

First, gradually restore

Through the analysis of the fault phenomenon and the judgment of the actual measured parameters, gradually narrow the scope of the fault, and finally implement the specific circuit or component where the fault occurred, which is a sure, negative, then sure, then negative, and finally sure (judgment) of the judgment process.

For example: an inverter is powered on and no display is found on the operation panel. First of all, it must be judged that there is no DC power supply (you can use a multimeter to measure the DC power supply voltage). Upon further inspection, the high voltage indicator is found to be on (PN voltage is further measured to confirm), negating the main circuit high voltage circuit failure, and definitely the power supply to the operation panel in the switching power supply has a problem. If the AC voltage of this power supply is normal, there is no DC output and short circuit, it can be concluded that the rectifier of the power supply circuit is damaged. This example uses the typical gradual reduction approach. Its whole process is through analysis and parameter measurement, judgment, affirmation, denial several rounds, and finally determine the rectifier tube damage.

Second, following method

According to the working principle of inverter, along the fault site, along the signal path, step by step, directly to the fault location, and finally find the fault location method, simply put, is to follow the path to the end.

For example, an inverter output voltage is unbalanced. This failure is obviously caused by two possibilities. One possibility is that at least one of the six units of the inverter bridge is damaged (open circuit), and the other possibility is that at least one of the six sets of drive signals is damaged. Assuming that one inverter unit has no drive signal, we can further determine the location of the failure in the drive circuit by tracing it back to its source. Specifically, in this example, we can check from top to bottom, that is, from the source of the drive signal, which is the output of the CPU.

When the CPU outputs a signal, check if there is a signal at the input of the optocoupler. If there is no signal, there is a break in the input from the CPU to the optocoupler. If there is a signal, check the output of the optocoupler and see if there is a signal at the output of the optocoupler. If there is no signal, it means the optocoupler is damaged. If there is a signal, check the input and output of the amplifier circuit. If there is a signal at the input and no signal at the output, it means the fault is caused by the amplifier circuit or the amplifier tube or related components are damaged. Then further implementation will be easier.

For the maintenance of inverter, we must think carefully, observe meticulously, and repeatedly deduce. Accumulate more experience, it is easy to find the most problematic places to prioritize troubleshooting. If it is not solved, and then combined with the above methods of systematic investigation. You can achieve twice the result with half the effort.