An Improved Performance Three-Phase Neutral-Point Clamped Rectifier with Simplified Control Scheme

In this paper, an improved performance 3-phase, neutral-point clamped bidirectional rectifier with simplified control scheme is proposed. A complete mathematical model of the rectifier using PWM controller is developed. A comparative analysis of two-level and three-level converter is done and the performance of both types of converters is evaluated in terms of the input power factor, input current THD, and ripple factor of the regulated dc output voltage. The merits and demerits of both types of converters are discussed. It is shown that the multi-level ac to dc converter with proposed control scheme is superior to its two-level counterpart and gives better performance like unity input power factor, negligible input current THD, and reduced-rippled regulated dc load voltage at a lower switching frequency and reduced voltage stress of the power semiconducting devices. The neutral point potential balance is also achieved with the proposed control technique