Predictive Finite-State Control—When to Use and When Not

Abstract

A multistep predictive algorithm eliminates overshoots of the current vector outside the boundary circle while the processor identifies the next optimal switching state vector following a boundary transition. The predictions of the current vector trajectories refer to a simplified machine model consisting only of the leakage inductance. Nevertheless is good accuracy of the predictions achieved. Operation at low switching frequency minimizes both harmonic distortion and switching losses. Using higher switching frequencies does not lead to noticeable improvement over ordinary carrier modulation. Maximum fundamental output voltage is achieved by predictive overmodulation.