Development of a new bridge-type chopper for low-voltage SMES applications

In this paper, a new bridge-type chopper having power electronic switches is proposed for low-voltage superconducting magnetic energy storage (SMES) applications. The energy charge and discharge characteristics of a high temperature superconducting (HTS) SMES device, including transient current through the HTS coil, maximum discharge time duration for the load, effective energy utilization factor, are numerically studied using the circuit analysis and iterative calculation methods, and finally verified by measurements on the developed chopper device. One new theoretical modeling in corporation with a simple digital control method is presented. Experimental and numerical comparisons of the bridge-type and conventional choppers show that the new developed bridge-type chopper is favorable for long-time power compensation with very high operation efficiency in the low-voltage power applications.