Cooperative Adaptive Control of Multi-Parameter Based on Dual-Parallel Virtual Synchronous Generators System

Presently, conventional fixed parameters are applied in dual-parallel virtual synchronous generators (VSGs), resulting in poor frequency response characteristics. Therefore, a multi-parameter cooperative adaptive control strategy is proposed in this article as a solution. The principle of the method is that when a frequency transient fluctuation occurs in the VSG, the frequency deviation and rate of frequency change are combined with the virtual inertia, damping coefficient, and P/ω droop coefficient to form an adaptive control system. A small-signal model of dual-parallel VSGs was built to analyse the impacts of the parameters on the stability of the system in each phase. The boundary conditions of the parameters such as virtual inertia, damping coefficient, P/ω droop coefficient and virtual inertia adjustment coefficient are further pinpointed to improve parameters’ values. In the simulation results, the strategy put forward in this article can increase the frequency and amplitude by 54.66% and the recovery time by 49.65% when the system is disturbed. The simulation and the StarSim experimental platform are verified that the strategy proposed in this article can effectively optimize the frequency fluctuation response characteristics of the grid-connected VSG system in different cases, enhancing the dynamic performance and safety and stability of the system.

I. Introduction

In Order to solve the energy crisis and environmental pollution, new energy sources such as wind and solar energy have gradually been widely used due to their flexibility and non-polluting. A high proportion of new energy is connected to the power grid, and the power system is progressively transformed from centralized to distributed power generation. Due to the reduction in the capacity of traditional synchronous generators, traditional inverters lack the inertia and damping of traditional motors, which makes the power system more vulnerable. Due to the influence of power fluctuations and system failures, the power system will face serious stability problems [1], [2], [3].