弱电网复杂工况下自适应PI+VPI谐波电流跟踪控制

In order to solve the problem of the degradation of the harmonic compensation performance of the active power filter (APF) under the complex working conditions of the weak power grid, an adaptive proportional integral plus vector proportional integral (PI+VPI) harmonic current tracking control strategy was proposed. The strategy is composed of an adaptive notch filter based phase-locked loop (PLL) and an adaptive PI+VPI current tracking control method, and a series of adaptive lattice notches are introduced to suppress the disturbance caused by the conditions of grid-side voltage distortion, imbalance and a large range of frequency deviation and improve the phase and frequency estimation accuracy of the grid. Meanwhile, the phase and the frequency information are used to calculate the Park transform in harmonic detection and updating of PI+VPI current tracking control law parameters in current tracking control. Then the PI+VPI current tracking controller with resonant frequency adaptation capability is constructed to improve the gain of the resonant frequency point and ensure that the APF can maintain the best compensation performance under the above weak grid conditions. Finally, simulations and experiments show that the phase and frequency estimation errors of the proposed adaptive notch filter based PLL (ANF-PLL) can still be maintained high accuracy after the frequency deviation of +4 Hz, and the proposed adaptive PI+VPI strategy can ensure that the current THD of the grid side after compensation is kept below 3.68% in the frequency deviation range of ±4 Hz, and the harmonic compensation performance has obvious advantages under the complex working conditions.