How to judge the quality of IGBT drive board?
The detection of the driving board, usually the driving board and the main board are separated from the main circuit, that is, the driving IC is powered by the power supply, and the driving circuit can of course be overhauled separately; Without an oscilloscope, the quality of the driving board can of course be detected; Test board, usually the driving board and the main board are separated from the main circuit, that is, detached from the inverter housing. The two circuit boards are connected to supply power to the switching power supply, so that various control circuits can be output. The main board (including the display panel) is connected with the driving board. At this time, faults such as OH, OC, OL, etc. will be reported, and measures will be taken from the circuit to shield the fault signals, and the display panel will be operated to make the circuit in two states of running and stopping, and the detection will be carried out directly. The advantage of this maintenance method is that not only the fault of the driving board is checked, but also the fault of the whole machine is actually checked, and the whole pulse transmission link is actually checked. This is a good way to get there in one step. It is also very convenient to synchronously check other faults of the main board and the driving board, and repair the connection between the display panel, the main board and the driving board by using the signal and status display of the circuit itself.
Of course, it is also possible to supply power to the driving IC and overhaul the driving circuit respectively. The IC is an optocoupler circuit, and the primary side and the secondary side each have a power supply system. The power supply of the primary input side is 5V (after current stabilization), and the power supply of the secondary output is 22V (divided into positive power supply and negative power supply). Pay attention to providing two power circuits during maintenance. When the input side current loop is provided, the strain of pulse output is 15 V; When the input current loop is interrupted, the strain of the pulse output is about -7V. At the same time, according to the output current capacity of the pulse output, connect a load resistor (the resistance is equal to the gate resistance) at the output end, and connect a DC current file in series with the load resistor, so that the output current values of the six channels should be basically equal. For example, the positive current output capacity is 100mA, the negative current output capacity is 40mA, and the six circuits are basically the same, which shows that the driving circuit is basically no problem. If the test result does not meet the above conditions, it means that the circuit is faulty. Check and troubleshoot.
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