基于扰动观测器的模型参考自适应控制用于未知惯量电网的惯量支撑

Existing studies on inertia control depend on knowing or estimating the grid equivalent inertia when renewable energy sources (RESs) are present. To eliminate the need for accurate knowledge or estimate of the grid equivalent inertia, this paper proposes employing the battery energy storage system (BESS) to inject inertia into the grid when RESs are connected to the grid, maintaining the original grid inertia—essentially the value without zero-inertia resources. This is accomplished by designing a model reference adaptive control (MRAC) scheme that uses the power system inertia without zero-inertia resources as a reference to determine the inertia that the BESS must inject. To this end, disturbance observer (DOB)-based MRAC is proposed and integrated into the BESS droop control loop. The DOB estimates load changes based on frequency deviations, and the MRAC uses this information to adjust the BESS output power, ensuring the system inertia and frequency reach the reference. Since the performance of the DOB affects the model reference adaptive controller, the steps to designing the DOB and proper tuning of the adaptation gain, which yields fast dynamics and satisfactory results, are laid out. Moreover, a novel approach is presented for enabling participation of multiple BESSs in inertia control. Real-time simulations are carried out to verify the efficacy of the proposed method in maintaining the grid inertia, and thus the system frequency, around the desired value.