| 摘要 |
PURPOSE:To set a fundamental wave power factor to ''1'' by controlling the amplitude and phase of an armature current from each control signal for the effective and reactive powers as observed from a power terminal of the motor driven by a cycloconverter, thereby preventing the variation in the reactive power. CONSTITUTION:An arithmetic unit PQC calculates effective power P and reactive power Q from the detections signals of a transformer PTs and a current transformer CTs. The deviation epsilonQ between the detected value Q of the reactive power outputted from a comparator C1 and the instructed value Q* becomes an amplitude value I0* of the armature currents IU-IW through a control compensator HQ(S). The power command value P* is obtained from the torque command value T* obtained by the speed deviation epsilonN=omega*-omega and the speed detected value, and the deviation epsilonP between the detected value P of the effective power P outputted from a comparator C3 and the instruction value P* becomes cosine value cosgamma of the phase angle gamma by a control compensator HP(S), a divider DVM and a limiter LIM. A firing control signal alphaU is obtained through a current control circuit CONT-U from the phase unit sinusoidal waves phiU-phiW outputted from 3-phase sinusoidal wave signal generator PTG and the amplitude value I0*. |
