Fast Estimation of Phase Angle for Three-Phase Voltage Systems under Distorted Conditions

This paper proposes a fast and robust technique for instantaneous phase angle estimation of three-phase voltage systems under unbalanced and distorted conditions. It mainly relies on the Clarke transformation, Teager energy operator and delayed signal cancellation (DSC) approach. Unlike an adaptive DSC-based synchronous-reference frame phase-locked loop (PLL), the proposed technique avoids interdependent loops, thus increasing the overall stability and easing the tuning process. Moreover, it removes the phase loop of the PLL, hence eliminates the requirement of in-loop filter (low-pass filter) and/or loop filter (proportional plus integral controller). As a result, the tuning of these filters is not required and a quicker response is produced. The proposed technique also avoids inverse trigonometric function operation. In addition, it shows harmonics immunity at steady-state and can generate fast dynamic response with a settling time less than one nominal fundamental cycle. Both simulation and experimental results are presented to reveal the benefits of the technique.