Direct Power Control Strategy to Balance Capacitor Voltages of PWM Three-Phase Three-Level NPC Rectifier

Abstract

In the paper, modelling and control algorithm to balance capacitor voltages of the PWM three-phase three-level
neutral point clamped rectifier with direct power control method is presented. The instantaneous active and
reactive power are analyzed in order to derive the switching table. The DPC model is simulated using
MATLAB/Simulink software. The simulation results show that the control method has a good dynamic response
of active and reactive power. The line current waveforms are sinusoidal and low-distorted while the input unity
power factor (UPF) is maintained. In addition, the DC bus voltage is controlled and the voltages across the two
capacitors are balanced. Theoretical analysis is demonstrated through simulation and empirical results.