Active Disturbance Rejection Control Strategy for Power Coordination of Interlinking Converters in AC/DC Microgrids

ObjectivesTo ensure stable and smooth energy flow between AC and DC subnets and address the degradation of interlinking converter control performance caused by uncertain switching of high-power AC or DC loads, a power coordination control strategy for interlinking converters based on a second-order linear active disturbance rejection controller is proposed.MethodsBased on the transmission power of the converters, a current observer is utilized to estimate the disturbance caused by high-power load switching in the AC or DC subnet. Then, the disturbance is compensated in the feedback channel of the control loop to ensure that the frequency of the AC subnet and the bus voltage of the DC subnet can always remain within permissible ranges during high-power load switching. Finally, an electromagnetic transient simulation model of an isolated AC-DC hybrid microgrid is established based on MATLAB/Simulink to verify the effectiveness of the proposed ADRC-based power coordination control strategy.ResultsWhen a large power load is switched on in an independent microgrid, the proposed control strategy can accurately regulate the active power flowing through the interconnected converter in real time, ensuring that the AC subnet frequency and DC bus voltage are within the stable operating range, so as to solve the problem of using traditional PI controllers. The problem of system instability caused by lagging tracking large load switching.[Conslusions] A comparison with traditional control strategies shows that the proposed control strategy improves the reliability and stability of the microgrid.