System implementation and testing of STRETCH meat grinder with ICCOS

By applying the principle of ICCOS (Inverse Current Commutation with Semiconductor devices) in a STRETCH (Slow Transfer of Energy Through Capacitive Hybrid) meat grinder system, a novel circuit topology called STRETCH meat grinder with ICCOS was proposed by Tsinghua University in 2013. It can not only raise the amplitude of opening current, but also reduce the cost of the STRETCH meat grinder circuit obviously through the replacement of IGCT with thyristor. This paper discusses the overall design, system implementation, and testing results of a STRETCH meat grinder with ICCOS system with roughly 1kJ inductive energy. The load is a spiral coil with 1.4mΩ resistance and 1.4μH inductance. With closed-loop control strategy, the system detects the charging current of the inductors. When it reaches the designated value, the triggering signal for ICCOS is delivered and after the proper delay time, the triggering signal for discharging the voltage on the pulse forming capacitor is delivered. The current of the inductors and the load are measured by Rogowski coils. The opening current is 1kA and the maximum load current is close to 4kA. All the voltages on the switches are lower than 1kV. The experimental results are consistent with the simulated ones, which verified the correctness of the theoretical analysis and proved the applicability of the STRETCH meat grinder with ICCOS for larger storage energy.