Method and apparatus for PWM control of voltage source inverter

A voltage source inverter for controlling an AC motor, the voltage source inverter comprising:

• a controller having an input and an output, said controller configured to produce a first signal;
• a switch network having an input coupled to said output of said controller and having an output configured to couple to the AC motor, said switch network configured to:
• produce an output voltage vector and a zero vector based on said first signal;
• and
• provide a voltage to the AC motor corresponding to said output voltage vector;
• and
• a modulator having an input coupled to said output of said inverter circuit and having an output coupled to said input of said controller, said modulator configured to modify said zero vector when said output voltage vector is in a distortion region, said distortion region based on said switch network.

A method for controlling a voltage source inverter, the method comprising:

• monitoring an output voltage vector of the voltage source inverter, the output voltage vector based on a switching cycle, the switching cycle having a plurality of phase legs and a zero vector;
• producing a modified switching cycle by modifying a duty cycle of each of the plurality of phase legs by a duty cycle of the zero vector when the output voltage vector is in a distortion region;
• and
• providing a DPWM signal to the voltage source inverter, the DPWM signal having the modified switching cycle.