High-voltage inverter fault handling method - Solutions - Huaqiang Electronic Network

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The high-voltage inverter has a highly intelligent computing level and a complete fault detection circuit, and can provide accurate positioning for all faults, and make clear instructions on the main control interface. In practical applications, we found that common faults can be divided into control channel anomalies, IGBT overcurrents, overvoltage faults, and so on. Here are the common faults and the causes and treatments.

1. Control channel abnormal fault

The abnormality of the control channel is usually caused by the fiber-optic communication between the PWM board and the power unit board. Generally, the following situations are caused:

1. Poor contact of the fiber connecting part or the fiber head falling off;

2. Dust is accumulated inside the fiber signal transmitting/receiving device;

3. Fiber breakage;

2. The optical fiber communication control board is damaged;

In the case of a fiber failure, it is first necessary to determine whether the power unit is faulty or the controller side is faulty, and the method of adjusting the optical fiber can be judged. The fiber corresponding to any one power unit in the same phase of the fiber board in the controller is reversed to the faulty fiber. If the fiber fault in the power-on monitoring interface is still in the original position, it indicates that the fiber board is damaged, and vice versa. If the fiber fault displayed on the interface has been replaced, it indicates that the power unit is faulty. In this case, consider replacing or repairing the faulty power unit.

3. IGBT overcurrent fault causes and solutions

IGBT is the most critical power device in high-voltage inverters. As a high-power composite device, IGBT has the problem of locking phenomenon caused by over-current. In order to improve the reliability of the system, some measures have been taken to prevent damage due to overcurrent. There are several reasons for the IGBT overcurrent fault:

1. The inverter output is short-circuited;

2. The IGBT in the power unit is broken down;

3, the drive detection circuit is damaged

4. The detection circuit is disturbed;

The detection method is to find the corresponding module according to the fault location displayed on the monitoring interface, and to open and check whether the IGBT is damaged. The method of judging is to find the positive V+ and the negative V- of the internal DC bus of the power unit, and connect the black test pen of the multimeter to the V+. The red test pens are respectively connected to U and V, and the diode files should display the value of about 0.4V. The reverse phase shows the infinity. When the red test lead is connected to the V-, repeat the above steps, the same result should be obtained, otherwise it can be judged. IGBT damage needs to be replaced.

4. Causes and solutions for overvoltage faults

The cause of overvoltage is generally the overvoltage from the input side of the power supply. Under normal conditions, the fluctuation of the grid voltage is within the range of -10% to +10% of the rated voltage, but in special cases. Since the DC bus voltage rises with the supply voltage, the inverter trips due to overvoltage protection when the voltage rises to the protection value. In order to avoid the input side overvoltage, the tap of the transformer can be changed for adjustment. This method is only suitable for the case where the field voltage is always high. In addition, it is also considered to increase the absorption device on the input side of the power supply to reduce the overvoltage factor on the input side of the inverter.