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 includes a current command generator, a six-step flux controller and a current regulator. The six-step flux controller generates a flux modifier to regulate flux in a flux-weakening speed/load operating region of the electric machine when operating the electric machine in a six-step mode. The current command generator converts a desired torque to three-phase desired currents that are input to a dq0-dq transformer and combined with the flux modifier to determine a modified-flux direct-quadrature (dq) current request. The current regulator includes a proportional-integral feedback controller, anti-windup elements, a dq voltage limit element and a voltage magnitude limiter. The proportional-integral feedback controller and the anti-windup elements perform closed-loop current control on the modified-flux dq current request to determine commanded dq voltages.

主权项

1. A voltage source inverter controller for controlling an inverter electrically connected to a permanent magnet synchronous multi-phase AC electric machine, comprising:
a current command generator, a six-step flux controller, and a current regulator, wherein:
the six-step flux controller generates a flux modifier to regulate flux in a flux-weakening speed/load operating region of the electric machine when operating the electric machine in a six-step mode;the current command generator converts a desired torque to three-phase desired currents that are input to a dq0-dq transformer and combined with the flux modifier to determine a modified-flux direct-quadrature (dq) current request; andthe current command regulator includes a proportional-integral feedback controller, anti-windup elements, a dq voltage limit element and a voltage magnitude limiter, wherein the proportional-integral feedback controller and the anti-windup elements perform closed-loop current control on the modified-flux dq current request to determine commanded dq voltages, wherein:the dq-voltage limit element and the voltage magnitude limiter impose limits to the commanded dq voltages; andthe inverter converts the limited commanded dq voltages to pulsewidth-modulated stator currents to drive the electric machine in the six-step mode.