Voltage Oriented Control of Two Level and Three Level Neutral Point Clamped PWM Rectifiers

Pulse Width Modulated (PWM) Rectifiers are very popular for ac to dc conversion needs of the industry and utility grid. These converters support bidirectional power transfer, and act as boost rectifier with nearly unity power factor current drawn from the grid as well as provide controlled output dc voltage that is free of ripples at the dc side. To achieve this, a closed loop controlled converter is required. The objectives of any control technique is to regulate dc side voltage to achieve a near unity power factor (UPF), and to realize faster dynamic response to supply and load variations.Voltage Oriented Control (VOC) is one such technique that provides good dynamic response. In this paper, VOC of the conventional three phase two level PWM rectifier and three level Neutral Point Clamped(NPC) rectifier with Space Vector Pulse Width Modulation(SVPWM) technique is discussed.The paper aims at simulation and analysis of VOC based conventional three phase rectifier and three level NPC rectifier. The simulation is carried out using MATLAB/Simulink. The FFT analysis of each converter is compared with respect to the Total Harmonic Content in input current.