MOTOR DRIVE CONTROL WITH A SINGLE CURRENT SENSOR USING SPACE VECTOR TECHNIQUE

摘要

A drive system for a multi-phase brushless motor comprising a plurality of phases, the system comprising a drive circuit including switch means for varying the electric potential applied to each of the phases by switching the drive circuit between a plurality of states, a current sensor connected such that it can sense the instantaneous total current flowing through the windings, and control means arranged to provide pulse width modulated drive signals to control the switch means so as to control the time that the drive circuit switches between said states in each of a series of pulse width modulation periods, wherein the control means is arranged to control the switching times of the switch means so that sufficient time is spent in a sufficient number of active states for the current in each of the phases to be determined by means of the current sensor, and the control means is arranged to use space vector modulation to determine times which the circuit spends in each of the states in each period, and the control means is arranged, at high voltage demands, to abandon current sensing at least partially and provide a maximum available modulation index corresponding to a non-circular trajectory.