Trapezoidal PWM 전류원 인버터에서 최소 Speed Ripple을 위한 펄스 수 및 변조도의 결정

Selection of pulse number and modulation index for minimum speed ripple in trapezoidal CSI-PWM

Square-wave current source inverter drives suffer from torque pulsation and speed variation at low speed. Attempts to minimize these problems, CSI PWM strategies have been reported. It is shown that these PWM strategies are based on unnecessarily restrictive modulation laws. In this paper, trapezoidal PWM strategy for CSI is investigated theoratically by double fourier series and we proposed Harmonic Speed ripple Factor(HSF) that is independent of motor parameters and load conditions. Speed ripple are considered in T-PWM and square wave inverter by HSF. We obtain modulation index(M) and carrier ratio (CR) for minimum speed ripple.