Three-Phase Neutral-Point-Clamped (NPC)-Based High-Power Factor Converter with Matrix-Based Modulation

Line commutated AC-DC converters using diode/thyristor bridges suffer mainly from the drawbacks of unidirectional power flow and non-sinusoidal input current which operate at very poor power factor and inject harmonics into the AC system. Hence, it creates power quality problems. Over the last few decades, several new topologies have evolved and succeeded in eliminating the drawbacks of the line commutated converters and hence named ‘High-Power Factor converters’ (HPFCs). In the context of electric vehicle (EV) charging applications, three-phase HPFCs play a vital role. These converters are essential for efficient energy transfer between the EV and the grid. PFC ensures that the EV draws power efficiently from the grid, minimizing harmonic distortion. Components like high-power MOSFETs and IGBTs contribute to high efficiency. With increased power levels and voltage ratings above 800 V, three-phase two-level HPFCs are inadequate for optimal performance. Higher levels (≥3) are typically chosen to meet high power demands. These multilevel HPFCs provide increased power demand while reducing switching stresses and improving wave shape quality, making them an exact substitute for earlier two-level HPFC models. The multilevel HPFCs often come with complex modulation principles which in turn increase the complexity of the overall control system. In the digital implementation, this results in forcing the sampling time to a high value. To address this issue, this paper introduces a new matrix-based space vector pulse width modulation (MB-SV-PWM) for three-level HPFRs. It requires less computing power, can be easily implemented in the digital domain, and can be extended to multilevel converters. To demonstrate the effectiveness of the proposed modulation technique, it is compared to standard sinusoidal-PWM and SV-PWM using MATLAB/SIMULINK.