531X301DCCAFG2 Parallel resistance capacitance absorption circuit

When the intermediate frequency power supply thyristor works in series, the voltage equalization of each device is a very important issue. Each working cycle of a thyristor can be divided into five stages: forward blocking, opening, conduction state, reverse recovery, and reverse blocking. In the forward and reverse blocking states, the voltage distribution of series devices is mainly determined by their blocking volt ampere characteristics. 531X301DCCAFG2 devices with higher blocking voltage will withstand higher voltage under the same leakage current conditions; During the turn-on phase, the thyristor transitions from an off state to an on state.

The use of voltage equalization for 531X301DCCAFG2 mainly needs to solve the voltage distribution problem in three states: forward and reverse blocking, opening, and recovery. To ensure voltage balance of the device in the blocking state, it is necessary to parallel a voltage sharing resistor for each series connected thyristor. The selection principle for the resistance value of 531X301DCCAFG2 is that the current flowing through the resistor at the actual working voltage is 2 to 5 times the leakage current of the thyristor at the rated junction temperature. Due to the possible differences in the turn-on and recovery processes of 531X301DCCAFG2, it is essential to use a parallel resistance capacitance absorption circuit for dynamic voltage balancing. An absorption circuit with appropriate parameters can limit the unbalanced voltage of the series circuit to a certain range. The organization of 531X301DCCAFG2 is related to the recovery characteristics and working conditions of the series device. Generally, the absorption capacitance C is taken as 0.1 to 0.4 microvolts, and the absorption resistance R is taken as 8 to 20 ohms, The absorption capacitance and absorption resistance should be selected as non inductive and non inductive capacitors, and connected as short as possible to the nearest end of the thyristor.