最適台形波信号を用いた誘導電動機駆動用三相電圧形PWMインバータの出力特性評価

抄録

This paper presents steady-state performance evaluations of PWM inverter for 3φ induction motor using generalized and optimum trapezoidal-wave signal and wide-band variable carrier frequency, as compared with PWM inverter characteristics of introducing sinewave signal and wide-band carrier frequency. PWM output voltage with lower harmonic contents and larger effective AC value is obtainable under the optimum trapezoidal-wave signal PWM scheme.
The optimun trapezoidal signal pattern is characterized through introducing slope factor L of the generalized trapezoidal-wave signal and modulation factor M. This is theoretically determined as L=0.2π from the conditions of the realization of minimized lower harmonic components and maximized utilization factor of DC voltage to PWM voltage.
In particular, the induction motor variable-speed drives using the optimum trapezoidal-signalbased PWM inverter are more effective because the stator current distortion and torque pulsation are considerably reduced in the range of lower carrier frequency in the comparison with those in the case of using sinewave signal. The experimental results are illustrated in breadboard.