CONTROLLER OF CURRENT TYPE INVERTER

摘要

PURPOSE:To suppress the harmonic wave content rate to a low value by applying the prescribed time firing pulse so that the pulse width distribution of an output current approximates the peak value distribution of sinusoidal wave. CONSTITUTION:A clock signal of frequency proportional to the frequency value command value of an inverter is outputted from a clock generator 71. A frequency divider 79, a reference pattern generator 72 and irregular period triangular wave generator 77 respectively form a distribution signal, a reference signal and a triangular wave of irregular period synchronized with the reference signal by the output signal of the clock generator 71. A pulse S for simultaneously turning ON self-extinguishing a elements connected simultaneously to the positive and negative sides of the inverters by comparing the triangular wave with the AC output current command value by a shortcircuiting pulse generator 78. A PWM pattern generator 73 and a composite circuit 74 output a firing pulse approximated to the peak value distribution of the sinusoidal wave in the pulse width distribution of the output current.