PWM rectifier with LCL filter based on parameter identification and a new active damping control

To control pulse width modulation (PWM) rectifier with LCL filter, not only grid voltages, currents and DC bus voltage, but also voltages or currents on capacitor branch should be detected in order to eliminate resonance. So many sensors cause high cost of the rectifier. And because the detected power grid voltage contains influence of the actual impedance of the grid, the stability of the rectifier is affected. In this paper, a control strategy based on parameter identification of power and virtual flux oriented was studied. To achieve accurate virtual flux observation, considering the particular complexity of the LCL filter, before starting the rectifier, Genetic Algorithms was used to identify grid inductance, frequency, amplitude and initial phase angle. And for resonance problem of the LCL filter, a new active damping control method was proposed, which gave directly feedbacks of high frequency component of the current on rectifier side through a first-order high-pass filter. The frequency domain model was set to analyze the high-pass filter parameters on the resonant inhibiting effect. This strategy only detected the DC bus voltage and the rectifier side of the two-phase current, eliminating power grid voltage sensors and voltage or current sensors on capacitive branch. Finally, simulation and experimental results prove the effectiveness of the proposed control strategy.