Discontinuous pulse-width modulation method

A discontinuous pulse width modulation method applied to a three-phase converter, comprising the steps of

• shifting an obtained first three-phase modulation wave upwards to obtain an upward-shifted three-phase modulation wave, and shifting said first three-phase modulation wave downwards to obtain a down-shifted three-phase modulation wave;
• obtaining an upward-shifted zero-sequence component based on said upward-shifted three-phase modulation wave, and obtaining a down-shifted zero-sequence component based on said down-shifted three-phase modulation wave;
• obtaining a start time-point of a transition interval based on said upward-shifted zero-sequence component and said down-shifted zero-sequence component;
• obtaining a target zero-sequence component within said transition interval based on an obtained first zero-sequence component, said start time-point and a time-point of sign switching occurring to said first zero-sequence component;
• obtaining an end time-point of said transition interval based on said first zero-sequence component, said target zero-sequence component within said transition interval and a preset difference threshold;
• said transition interval being an interval between said start time-point of said transition interval and said end time-point of said transition interval;
• said start time-point of said transition interval being prior to said end time-point of said transition interval;
• and
• adding said first three-phase modulation wave and said target zero-sequence component together to obtain a target three-phase modulation wave, and said target zero-sequence component within a non-transition interval being said first zero-sequence component.