Field-Oriented Control by Forced Motor Currents in a Voltage Fed Inverter Drive

Abstract The paper proposes an optimally pulsed voltage fed inverter drive with field oriented control, in which the standard pulsewidth modulator as well as the dynamic decoupling system are completely eliminated. Instead, the reference current components supplied by the field oriented control system are used to directly control the switching state of the inverter with the aim of forcing the actual stator current vector to trace the time-variant locus of the current reference. The inverter switching control includes an algorithm which ensures either minimum harmonic torque at minimum switching frequency or, in the case of large-signal transients, operation at steepest possible current gradient. The optimization is being performed at steady state and transient operation, including operation at zero stator frequency.