VSS Current Control Strategy for a Three Phase VSI

This paper introduces a new current control principle for three phase VSI. The transistor switching vector for the current control is determined directly from the Lyapunov stability condition in order to select the most effective transistor switching vector. To reduce the switching frequency of the proposed current control algorithm, sequential switching among the transistor switching vectors is introduced, which is described using a novel recursive matrix logic controller approach for description of the discrete event systems. Next to the systematic control design procedure, simplified implementation is major benefit of the proposed approach. Instead of traditional coding, the control algorithms are loaded in the form of logical matrices. The approach is illustrated by the design of event-driven current controller for a three phase inverter fed Permanent Magnet Synchronous Machine. The design is examined by simulations and experimentally confirmed.