High Efficiency and Low Acoustic Noise Drive System Using Open-Winding A. C. Motor and Two Space Vector Modulated Inverters

Abstract

The combining of the outputs of two inverters using inter-phase reactors is a widely used method for supplying large a. c. drives rated at more than several thousands kW. Certain drawbacks are associated with this method, such as high acoustic noise and high losses due to the inter-phase reactors.
To overcome this problem, in this paper, a new low acoustic noise and high efficiency drive system using an open-winding a. c. motor and two space vector modulated inverters, is proposed. This configuration consists of a 3-level inverter with switching at once every cycle and a 2-level inverter of about 1kHz switching frequency, connected respectively to the opposite terminals of the open-winding motor. With the proposed configuration, good current waveforms and high efficiency can be obtained.