A new energy optimizing control strategy for switched reluctance motors

This paper describes a new and machine-independent method to minimize the energy consumption of a speed controlled switched reluctance motor (SRM). The control strategy is to vary the duty cycle of the applied DC voltage in order to obtain the desired speed quickly and when operating in steady-state vary the turn-on angle (a_on) of the phase voltage to minimize the energy consumption. The power flow is measured in the DC-link and used to control the turn-on angle. Simulations carried out on a three-phase 6/4 pole SRM justify the algorithm and the physical implementation in a Siemens SAB 80C517A microcontroller is described. Measurements on two different load systems show it is possible to minimize the energy consumption on-line in a speed controlled switched reluctance motor without losing the dynamic performance. A comparison with an ordinary mode-shift controlled SRM shows more than an 8% increase in overall efficiency for some operation points. The algorithm is fully applicable to other switched reluctance motors at other power levels or with other pole configurations