Calculation of switching frequency in current hysteresis controlled switched reluctance drives

This paper illustrates the variation of average switching frequency in current hysteresis controlled switched reluctance drives. While the dependence of switching frequency on torque and speed can be understood and calculated qualitatively using simplified equations, accurate results can be obtained only from detailed simulation models. The results can be used to estimate power converter switching losses or acoustic noise spectral components caused by the current control. It is shown that average switching frequency varies significantly over the torque-speed range whereas the maximum average switching frequency is almost independent of torque and speed for a fixed hysteresis band and unsaturated conditions.