Integrated Voltage Support and Power Quality Management Technology Based on Photovoltaic Inverters

With the large-scale integration of new energy into the grid, low inertia and harmonic problems will arise in the power grid. Existing literature mainly focuses on using grid-forming control to improve the inertia and stability margin of the power grid, but lacks attention to harmonic problems. This paper first analyzes the interaction and influence between background voltage harmonics and load current harmonics in weak grid conditions. On the basis of traditional grid-forming control, a virtual impedance method is introduced to propose a harmonic suppression technology based on photovoltaic converter. On the one hand, the proposed method can support the grid voltage, and on the other hand, it can suppress the harmonic current caused by the background harmonic voltage brought by high proportion power electronic devices. Finally, the correctness of the proposed method has been verified through various simulations.