CONTROLLING CIRCUIT FOR CURRENT TYPE 3-PHASE INVERTER

摘要

PURPOSE:To improve the adaptability of a current type 3-phase inverter by deciding the phase difference alphaN to the varying time point at the load current after the variation and selecting the thyristor to be conducted, thereby reducing pulsating torque. CONSTITUTION:The phase difference alphaT from the start of the state of 1' of a load currentIL at the present time to the end of the state of 1' in the load currentIL after the variation is calculated by an alphaT arithmetic unit 16, while the phase difference theta from the start of the state of 1' of the loadIL at the present point to the varying time point c is compared by (alphaT-theta) arithmetic unit 18, thereby calculating (alphaT-theta). An arithmetic unit 20 selects the state of the load currentIL after the variation at the varying time point is selected by the magnituide relation to a certain period based on the output of the unit 18. Then, the phase difference alphaN from the start of the state to the varying time point is calculated, thereby selecting the thyristor to be conducted.