Single-phase VSM based on dq coordinate

Virtual synchronous machines (VSM) is a three-phase grid friendly inverter with widely used in microgrids. This paper proposes a single-phase VSM with a single-phase park transform unit (SPPTU). the SPPTU can perform park transformation on the single-phase current and voltage signals to obtain the dq components of the current and voltage signals and offer a dq coordinate system for the single-phase VSM algorithm. The results after the calculations of the electromagnetic torque Te, active power P and reactive power Q in VSM algorithm based on this dq coordinate system do not have the second harmonic component. Thence, the algorithm in the single-phase VSM with SPPTU can delete the second harmonic filter compared to the old algorithm of single-phase VSM without SPPTU, and improve the control accuracy furthermore. The single-phase VSM is based on paper [5] introduced in Section I with improvements, so it also includes fast current loop proposed by the paper. We present the performance of the novel features of single-phase VSM through a series of simulations. In addition, we also present the design of the current controller. The results show that the single-phase VSM leads to a performance as good as the VSM from [5] in terms of output active power oscillations and stability.