Patent ID: 8143840
Filing Date: 2012-03-27
Classification: H02P

Abstract:
1. A device for controlling an induction motor (IM) comprising: a voltage/frequency (V/F) controller configured to receive a controlling frequency, and output a corresponding controlling voltage according to a predetermined relationship of the controlling voltage rising with the increasing of the controlling frequency; a pulse width modulation (PWM) controller configured to receive the controlling voltage and the controlling frequency, and generate PWM signals according to the controlling voltage and the controlling frequency; a converter configured to receive the PWM signals, and control the IM according to the PWM signals; a first arithmetic logic unit (ALU) configured to receive an instruction frequency and an adjusting frequency, wherein the controlling frequency being obtained by subtracting an adjusting frequency from the instruction frequency by the first ALU; and a speed controller and a second ALU, wherein the speed controller is configured to output the instruction frequency according to a speed difference worked out by the second ALU; wherein the V/F controller is configured for outputting a controlling voltage greater than zero in response to the controlling frequency being zero, and increasing a controlling voltage in response to an increased controlling frequency as in the predetermined relationship.