Patent ID: 9225282
Filing Date: 2015-12-29
Classification: H02P

Abstract:
1. A method of controlling an output voltage of an inverter driving an electric motor, the method comprising: calculating a current total harmonic distortion (THD) of a current output to the electric motor; comparing the current THD with a reference current THD; adaptively determining a pulse width modulation (PWM) method to be changed from a first modulation method, that reduces harmonic components of the current output to the electric motor, to a second modulation method, that reduces a switching frequency of the inverter, when the current THD is less than the reference current THD, and to be changed from the second modulation method to the first modulation method when the current THD is greater than the reference current THD, the PWM method modulating a pulse width of a control pulse signal for controlling the output voltage of the inverter; and generating the control pulse signal based on the determined PWM method; wherein the adaptively determining of the PWM method comprises adaptively determining the PWM method for modulation the pulse width of the control pulse signal as the current THD changes according to the output voltage and the switching frequency of the inverter.