High bandwidth measurement of SRM torque ripple

An indirect SRM torque measurement technique is proposed which has the features of high bandwidth, low noise, no timing errors, and free from shaft mechanical oscillations. Differences between static and dynamic torque production are the technique´s main source of error. Offline measurement of static torque characteristics is required by the proposed measurement technique which evaluates the real time torque production from measured phase currents in association with an interpolation algorithm. Test results of the novel six switch 4 kW, IGBT, 20 kHz inverter bridge used to current feed the four phase 4 kW switched reluctance motor are shown. A torque ripple reduction method which minimizes both the average and the peak current, evaluated from the high bandwidth torque measurement technique, is also presented