METHOD FOR GATE SIGNAL GENERATION FROM PWM INVERTER, GATE SIGNAL GENERATOR, AND PWM INVERTER APPARATUS

摘要

PURPOSE:To improve the angular accuracy of apparatus, by obtaining the instantaneous values of the modulated waves of sine waves corresponding to angular command values in the present and next operation periods and by causing the modulated waves to approximate to each other through a linear function, the line of which passes through the two points, so as to compare the modulated waves with carrier waves. CONSTITUTION:The main circuit of PWM inverter apparatus is equipped with a rectifier circuit 2 and a capacitor 3 connected with an AC power source 1, and with an inverter circuit 4; and the inverter apparatus is also connected with a load induction motor 5. Further, the switching element of the inverter circuit 4 is ON-OFF driven by a drive circuit 6, and the circuit 6 is controlled by a controller 10 including a gate signal generator 20. A current command value is and the like are inputted from the outside to the controller 10, which is composed of an integrating operational means 12, a next angle command value operational means 14 and others. Then, the instantaneous values of the modulated waves of sine waves in the present and next operation periods, and the modulated waves are caused to approximate each other by a linear function, the line of which passes through the two points, and compared with the carrier waves of triangular waves. Thus, the timing of ON-OFF change-over becomes ideal.