METHOD AND APPARATUS FOR CONTROLLING AN ELECTRIC MACHINE IN A SIX-STEP MODE

摘要

A voltage source inverter controller for controlling an inverter electrically connected to an electric machine comprises: an electric current command generator; a six-step flux controller; and an electric current regulator. The six-step flux controller generates a flux modifier for regulating flux in the flux-weakening velocity/load operation region of the electric machine when operating the electric machine in a six-step mode. The electric current command generator converts wanted torque into a wanted three-phase electric current which is input into a dq0-dq transformer and is combined with the flux modifier to determine a modified-flux direct-orthogonal (dq) electric current request. The electric current regulator includes: a proportional integral feedback controller; an anti-windup element; a dq voltage limiting element; and a voltage magnitude limiter. The proportional integral feedback controller and the anti-windup element determine a command dq voltage by conducting a closed-loop electric current control with respect to a modified-flux dq electric current request.