A VCB and IGBT based combination switch and its application in power quality improvement

A new type controlled switching device is introduced, which based on vacuum circuit-breaker (VCB) and power electronic switch(IGBT) to form the combination switch module. The structure and working principle of provided combination switch were emphatically expounded, especially the open and closing process and controlling strategy were discussed in detail. The researched VCB with permanent magnet actuator, and the synchronous controller of combination switch module based on the digital signal processor, in which the algorithm of average series for zero-crossover phase difference is adopted, so the phase information of power grid can be extracted rapidly and accurately, and synchronous tracing pulses can be procreated. When remote control instructions are received, according to the phase information of power grid the combination switch acts synchronously to ensure that the operation time of combination switch opened and closed in right position. The application of introduced combination switch for power quality control and improvement is present in this research also. In this control device, the real-time acquisition of electrical parameters is adopted and the crossover point of reference signal is detected by average series for zero-crossover phase difference algorithm. Accompanied with improved appropriate switching strategy, the device can operate shunt capacitor banks on expected target point.