Analysis and Simulation of the Three Phase PWM Rectifier Based on Virtual Flux Oriented Control (VFOC)

The increasing use of rectifiers on many industrial applications and mainly of Three-phase pulse width modulated (PWM) rectifiers that require very high performance. Since these static converters must be adapted by sophisticated controls to improve waveform quality, reduce harmonic content, absorb sinusoidal currents, and maintain unity power factor.

Where the objective of this paper is to model and apply control technique: VFOC (Virtual Flux-Oriented Vector Control) without the use of voltage and current sensors. This control technique is used to control a three-phase pulse width modulated (PWM) rectifier connected to the electrical grid via an RL filter. The goal is to achieve efficient DC link voltage control, improve the shape of the grid currents, and achieve unity power factor.

The VFOC strategy relies on estimating virtual flux from measured voltages and currents, thus eliminating the need for voltage sensors while ensuring precise and stable control, even in the presence of network disturbances. This approach also allows for effective decoupling of active and reactive power.

Simulation results of VFOC (Virtual Flux-Oriented Vector Control) for several tests (no-load test, on-load test with constant and varying DC link voltage, and with changing load) are obtained using the MATLAB/SIMULINK environment. These results demonstrate efficiency and good performance, achieving good DC link voltage control, instantaneous active and reactive power, and unity power factor.