Modified space vector pulse width modulation technique to reduce DC bus ripple effect in voltage source inverters

摘要

A modified PWM space vector technique is described which includes a DC ripple voltage measurement scheme supplying feed-back to a DSP controller which then computes and generates the instantaneous PWM drives required for ripple voltage cancellation in a lightly filtered line voltage node, and executes the interface to the multi-phase power inverter circuitry. This preferably becomes a part of a closed loop motor speed control process. Use of the modified PWM drive in this manner greatly reduces the value of the filter capacitor required, allowing for the use of non-electrolytic capacitors having greater reliability and being available at lower cost.