Variable frequency drive device for induction motor

TLDR: In this article, the phase of gate pulses of a 2-phase induction motor was reduced by displacing and generating the phases of a plurality of switching elements of the motor's output, and the gate drive pulses were not synchronized with each other.

Abstract: PURPOSE:To reduce the capacity of a power source by displacing and generating the phase of gate pulses of respective plurality of switching elements. CONSTITUTION:A synchronous pulse (d) synchronized with the voltage of a single phase power source V is inputted from a power source synchronizer 3 to exclusive OR circuits 2a, 2b, and outputs c1, c2 having periods responsive to the set speed of a motor M are inputted from a 2-phase circuit 1 to exclusive OR circuits 2a, 2b. The outputs of the circuits 2a, 2b are inputted to an AND circuits 4a, 4b together with a phase control pulse (f) synchronized with the voltage of the power source V and having a pulse width proportional to the set speed and the output or inverted output from an unstable circuit 9, and the gate circuits G1, G2 of the switching elements of a 2-phase induction motor are controlled by the output. The gate drive pulses g'1, g'2 are alternately generated, and are not synchronized with each other.