| 摘要 |
PURPOSE:To improve the controlling characteristic by comparing a sinusoidal wave signal with a triangular wave of the frequency of the specific times to produce a PWM signal, and forming a main circuit of 12-phase multiplexer using 2 inverters, thereby effectively removing low order harmonic waves. CONSTITUTION:When a sinusoidal wave and a triangular wave signal are compared by an inverter controller 30 to produce a PWM signal, the frequency of the triangular wave signal is set to the odd times of 6 of the frequency of the sinusoidal wave signal. A main circuit controlled by the controller 30 is formed of 2 inverters 11, 12 sequentially having 30 deg. of phase difference, connected in series through output transformers 21, 22 to form 12-phase multiplexer. when such a PWM inverter is applied to the variable speed drive of an AC motor 2, a torque ripple over the entire speed range can be reduced. |
