Patent ID: 9093946
Filing Date: 2015-07-28
Classification: H02P

Abstract:
1. A method of controlling an output voltage of an inverter driving an electric motor, the method comprising: removing harmonic components of an output current, which is output to the electric motor, by using a low pass filter (LPF) and obtaining a fundamental component of the output current; calculating a current total harmonic distortion (THD) by using the fundamental component of the output current; comparing the current THD with a reference current THD; determining a pulse width modulation (PWM) method to be changed from a first modulation method for reducing the harmonic components of the output current to a second modulation method for reducing a switching frequency of the inverter if the current THD is less 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.