Continuous control for reduced vibration excitation in reluctance machines

High acoustic noise due to vibration in switched reluctance motors is a problem, which is increased by the discontinuous block wise control scheme. To reduce this problem, a continuous control scheme is suggested; hence the word `switched´ will be dropped here. Filtered force shapes from simulations are used to iteratively adjust a flux shape for the reluctance machine. The harmonics with high frequencies in the resulting reluctance forces gain much lower amplitude. This leads to less excitation of the machine resonances. The force has to be measured or calculated but mechanical properties like the eigenfrequency are not required to be known in detail. Simulations and experiments show the effectiveness of this vibration reduction and the effect on the motor efficiency is discussed.