Flexible Active Vector Distribution Strategy for Current Ripple and Switching Loss Reduction in Three-Phase Voltage Source Inverter

When adopting the space vector pulse width modulation (SVPWM) scheme, the vector distribution directly impacts the current ripple. Besides, the vector distribution also determines the switch sequence, consequently affecting the switching loss. Based on these features, a novel flexible vector distribution strategy is proposed to simultaneously reduce three-phase current ripple and switching loss in voltage source inverters (VSI). In this strategy, two new vector sequences are designed in addition to the conventional sequence. According to the three-phase current magnitudes order, one of the new sequences is further selected to achieve lower switching loss. Then, to reduce the current ripple, the relationship between the three-phase current ripple peak and the duration for each segment of the voltage vector under the selected sequence is quantitatively derived. On this basis, a novel online flexible active vector distribution method is proposed to calculate the appropriate duration for each segment and choose the optimal vector distribution, which achieves the lower current ripple. With the proposed strategy, the current ripple and switching loss are significantly reduced, particularly for medium to large modulation index and power factor. Finally, simulation and experimental results are presented to validate the effectiveness of the proposed strategy.