A study on electromagnetic energy recovery in SRM system

In this paper, an efficient type of SRM (switched reluctance motor) system is presented. It shows high specific output power and energy conversion ratio through proper matching the driving conditions with the electromagnetic structure. For the best utilization of the torque producing capability of the system, two driving conditions are required. The first is to get the current in the form of a flat-topped waveform in driving mode. The other is to recover electromagnetic energy as quickly as possible at turn-off. The first condition is satisfied by a control strategy with voltage and switching angle controllers. Several considerations for the proper design of the recovery circuit are also presented in detail. They include considerations on the control method, amplitude of recovered energy and circuit parameters which can guarantee the successful operation of the system. The validity of the system proposed and the adequacy of parameter estimation are verified through test results obtained by operating the variable-speed SRM drive system