The essential of synchronous switching technology is to control switching action of a permanent magnet switch at optimum phase of voltage or current according to different load characteristics

thus to eliminate such electromagnetic transient effects as overvoltage and surge current.At present

the synchronous switching technology is mainly applied to synchronous switching of reactive power compensation capacitor bank.The authors developed a synchronous switching device for capacitor bank based on digital signal processor TMS320F2812.Synchronous switching is implemented with this device by using phase-locked loop to realize synchronous sampling

and by accurately extracting signal zero via FFT algorithm.This device is suitable for predicting the switching time with neural network

and can realize synchronous switching control.Experiment indicates that the synchronous switching time of the device is within 1 ms

and it can significantly weaken the transient effect in switching process of capacitor bank.