High performance space-vector PWM inverters using nonlinear voltage gain correction

Abstract

An inverter designed for constant V/F air-conditioner motor drives is introduced. A modified space-vector PWM method is studied so that the linearity of the inverter can be improved when modulation index M>1. Because constant V/F drivers for air-conditioner motors operate in a wide range output frequency, the synthesis of accurate output voltages has became an important issue. To resolve the problem, the well known instantaneous average voltage method is used for compensating for blanking time and input DC-link voltage ripple. The inverter is controlled by a M37705 single chip microprocessor and has been successfully used in A.C. compressor speed control of a home central air-conditioner system.