Fault phenomenon: the discharge inductance is heated or even burnt out in the boost load.
Fault analysis and treatment: there are three reasons for the discharge inductance heating.
a. In the fault analysis of the above example, if the capacity of the series parallel connected capacitor is very different, the current released by the DC charge will increase. If the capacity of the discharge inductance is small, it will cause heating.
b. The inverter pulse is asymmetric. The inverter requires that the two sets of inverter pulses differ by 180 ° from each other. If the difference between the inverter pulses is not 180 °, the time of positive and negative half cycles of the inverter output voltage is also inconsistent, resulting in inconsistent time for the compensation capacitor to be charged twice in a cycle. When the capacitor has not been fully charged in the long half cycle, the capacitor has been charged in the short half cycle, and a certain amount of charge has been accumulated on the capacitor. The greater the time difference between the positive and negative half cycles of the inverter voltage, the higher the DC charge, and the greater the current flowing through the discharge inductor. When the current reaches the level of one hundredth, the discharge inductor will cause heating or even burn out. Therefore, when the discharge inductance is heated, it is necessary to carefully check the symmetry of the inverter pulse. If it is asymmetric, it is necessary to analyze the cause, check the inverter pulse forming circuit, and solve the asymmetry of the inverter pulse. In the inverter pulse forming circuit, the two pulse forming circuits are symmetrical. If the inverter pulse is asymmetric, it may be caused by the change of capacitor capacity and resistance, or by the change of internal parameters of the integrated circuit.
c. One inverter thyristor is burnt out. When an inverter thyristor is burnt out, the equipment can often be started. At this time, if you do not pay attention to the operating state of the equipment and make the equipment work with faults, the intermediate frequency output voltage waveform is distorted. Through the above analysis, it can be seen that the current flowing through the discharge inductor is very large, causing it to heat or burn out.