Control performance of active damp LCL filter of three phase PWM boost rectifier

This paper presents three methods of a three phase PWM boost rectifier connected to the grid via a single stage L filter, an undamp LCL filter and an active damp LCL filter. The first method is the simplest method uses the biggest size of single stage L filter. Although this method is straightforward, it increases the system size and weight and contains high frequency current components. The second method uses an LCL filter instead of an L filter for size and weight reduction. While size and weight can be reduced, it causes a stability problem around the resonance frequency. The last method solves all these problems by an improved control algorithm to maintain system stability. The active damp LCL filter is that it can reduce a current ripple of the system to conform to the standard. Moreover, it has a faster response than the conventional single state inductor filter. This paper presents mathematical models and implementation of the filter circuit for performance comparison. The results from a case study with 10 kW load indicate that the active damping LCL filter has nearly the same performances as single stage L filter but it has small size of filter inductors, no high frequency of the current and fastest dynamic response.