An improved sensorless driving method of switched reluctance motors using impressed voltage pulse

We propose an improved sensorless drive method of switched reluctance motors (SRM) using impressed voltage pulses. Some drawbacks of the method using impressed voltage pulse at unenergized phases to detect the inductance characteristic have been improved The proposed method has the features: only one unenergized phase has been injected with impressed voltage pulse, that simplifies both hardware and control algorithm, and a new idea to determine the injection timing for impressed voltage pulse has been introduced, that mostly eliminates the negative torques caused by some residual currents. Because the proposed method is very simple, instead of an expensive DSP, the entire experimental system has been implemented in an analog and digital circuit-FPGA (field programmable gate array)