Dynamic Phasor-Based Modeling and Analysis of Selective Harmonic Compensated Single-Phase Grid-Forming Inverter Connected to Nonlinear and Resistive Loads

The presence of nonlinear loads in islanded microgrids causes significant deterioration of the quality of power supplied to consumers. Selective harmonic compensators (SHCs) such as proportional-resonant and harmonic controllers are conventionally used to reduce the level of total harmonic distortion (THD) caused by nonlinear loads. To design SHCs that can attenuate undesired harmonics, high-fidelity models and simulations are essential. Detailed converter models found in electromagnetic transients (EMT) simulators are accurate but demand significant computational resources and time. This paper proposes the dynamic phasor (DP) model of a single-phase grid-forming inverter connected to nonlinear (diode-bridge rectifier) and resistive loads. Results obtained from simulating the DP model are validated with results from detailed model simulation and experiment. Simulation results show that the DP model is 143 times faster than a corresponding detailed model. Experimental results confirm the high fidelity of the DP model in capturing harmonic currents and voltages in the case study system. The proposed DP model will be useful to researchers/engineers interested in conducting fast-paced and accurate system-level study of large power electronics-dominated grids.