Direct power control of three -level PWM rectifier under unbalanced and harmonically distorted grid voltage conditions

A modified direct power control (DPC) strategy for three-level neutral point clamped (NPC) converters under unbalanced and harmonically distorted grid voltage conditions is proposed in the paper. The modified (DPC) strategy is implemented in the stationary reference frame without the necessity of either the space vector modulation or the synchronous speed d-q transformation. A compensation method is adopted in the conventional DPC to eliminate the negative and harmonic sequence components of grid current for the purpose of obtaining the symmetrical and sinusoidal grid current. Finally, simulation results based on matlab validate the availability of the proposed DPC strategy.