Optimal current control strategies for surface-mounted permanent-magnet synchronous machine drives

The current waveforms for optimal excitation of surface-mounted permanent-magnet synchronous machines are set forth. Four different modes are considered, involving varying degrees of minimization of rms current and torque ripple. The optimized waveforms are markedly different than the traditional sinusoidal or rectangular excitation schemes. Inclusion of cogging torque and arbitrary degree of torque ripple minimization generalize this work over that of previous authors. An experimental drive and a detailed computer simulation verify the proposed control schemes.