A Novel Method to Detect Single Phase Reactive Current under Non-Sinusoidal Voltage

The traditional instantaneous reactive theory is one of strategies commonly used in reactive current detection. In reactive current detection of single-phase AC circuits, the traditional instantaneous reactive theory must build a virtual symmetrical three-phase circuit, so its algorithm is complicated and its real-time performance is bad. At the same time, the traditional strategy leads to comparatively big detection error when the voltage is non-sinusoidal, hence the detection method based on traditional instantaneous reactive theory is mainly apply to the case of sinusoidal voltage. In order to meet to the needs to detect reactive current under both conditions of sine voltage and of non-sine voltage, the paper proposes a novel method to detect single phase reactive current, which detects the grid voltage of sine or non-sine in real time and cooperates with a given standard sine function and a cosine function, and can obtain the phase of the fundamental voltage after calculation and being filtered by a low-pass filter. Based on the phase of the fundamental voltage, the reactive component can be extracted form the current detected. Theoretical analysis and simulation results show that the improved algorithm can accurately detect the reactive current under non-sinusoidal voltage.