Positive sequence detector based on cascaded delayed quadrature signal cancellation

This paper proposed a positive sequence detector (PSD) based on cascaded delayed quadrature signal cancellation (CDQSC). The delayed quadrature signal cancellation (DQSC) operator based on two orthogonal signals in dq-frame or αβ-frame can be tailored to eliminate any specified harmonic. The proposed DQSC operator can be further cascaded to stepwise reject all undesired harmonics. Then the conditioned voltage signal can be used in phase locked loop (PLL) to obtain the positive sequence component accurately and fast. When the frequency of the three-phase signal is variable, the detector also realizes frequency adaptability by introducing a frequency feedback loop (FFL). Experimental results show that the proposed PSD is effective and feasible.