基于扩张状态观测器的混合式配电变压器直流母线电压控制

Hybrid distribution transformer (HDT) can effectively suppress the power grid harmonics and stabilize the load voltage, which is of great significance at the end of the distribution network. In the case of load change, power grid voltage fluctuation or three-phase unbalance, the functions of harmonic compensation and maintenance of load voltage stability have problems, which are caused by the bus voltage instability on the DC side of the hybrid distribution transformer. This paper proposes a DC-link voltage control strategy based on the extended state observer (ESO), in which the total observed disturbance is compensated by feedforward to improve the stability of the DC-link voltage. At the same time, the stability of the designed ESO and voltage controller is analyzed in the frequency domain. Finally, in the simulation based on MATLAB/Simulink and the experiment, compared with the proportional-integral (PI) control, the designed controller is proved to have a faster response speed and better stability.