Improved Ip-Iq Harmonic Detection Algorithm Based on Mixed Second-and Third-Order Generalized Integrator

Abstract. Aiming at the influence of DC component and high-order harmonics on harmonic current detection accuracy, an improved ip-iq harmonic detection algorithm based on mixed second-and third-order generalized integrator is proposed in this paper. The MSTOGI filter is added to the traditional ip-iq structure, which effectively filters the DC component of the input signal and suppresses the high-order harmonics. The phase-locked loop of MSTOGI can provide a stable grid voltage frequency when the grid voltage contains high-order harmonics and DC components, so that the harmonic current can be detected more accurately. The traditional ip-iq method and the general SOGI-based ip-iq method are compared and analyzed by simulation examples, which verifies the effectiveness and reliability of the proposed harmonic detection method when the power grid contains DC component and high-order harmonic.