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A bidirectional integrated bus voltage conditioner (IBVC) for an isolated phase-shifted full bridge (PSFB) dc/dc converter is proposed to reduce the dc bus voltage oscillations in a cascaded power converter system, where a load converter is controlled tightly with high-control bandwidth. In the proposed method, unlike conventional dc bus voltage stabilization methods for which auxiliary switches are used, the multiplexing utilization of the full bridge switches at the primary side of a PSFB is adopted. In this paper, to improve the dc bus voltage stability, an equivalent virtual resistor is implemented by applying the duty cycle regulation for both legs of the PSFB. The effectiveness of the proposed method on the dc voltage stabilization is examined through simulations and experiments. The achieved results reveal that the dc bus voltage stability is significantly improved with the proposed method.

The study on the stability of DC bus voltage is one of the key issues for researching independent DC microgrid. This paper has studied the independent DC microgrid with photovoltaic and energy-storage systems. The variable step incremental conductance method was taken to realise maximum power point tracking (MPPT). The self-adaptive Fuzzy-PI controller was designed to optimise the traditional double closed-loop control strategy. The energy management system was built to achieve coordinated control of the independent DC microgrid. The simulation results show that the improved strategy can get better robustness and system performance comparing with the traditional PI method. [ABSTRACT FROM AUTHOR]

The study on the stability of DC bus voltage is one of the key issues for researching independent DC microgrid. This paper has studied the independent DC microgrid with photovoltaic and energy-storage systems. The variable step incremental conductance method was taken to realise maximum power point tracking (MPPT). The self-adaptive Fuzzy-PI controller was designed to optimise the traditional double closed-loop control strategy. The energy management system was built to achieve coordinated control of the independent DC microgrid. The simulation results show that the improved strategy can get better robustness and system performance comparing with the traditional PI method.

The constant power load (CPL) property of a load converter with tight control results in DC bus voltage oscillations in interconnected power converter systems. In this paper, a disturbance observer (DOB) feedforward compensation scheme is proposed to stabilize the DC bus voltage of a cascaded power converter. An equivalent DC link voltage control model and a disturbance observer are used to reconstruct the dynamic changes of the DC bus current to correct the inner current loop reference of the load converter. Simulation and experimental results show that the proposed method is effective in stabilizing the DC bus voltage. [ABSTRACT FROM AUTHOR]

To solve the problem of low inertia in DC microgrid and enable the distributed units to provide adaptive inertia support for the system under disturbance, this study proposes a novel adaptive inertia control strategy for DC microgrid combined with fast predictive converter control. In this strategy, adaptive coordinated inertia control of wind power system, AC power grid and energy storage system of the microgrid is designed according to the characteristics of corresponding micro‐sources. Therefore, inertial response of the DC microgrid under disturbance is improved through the regulation of controllable inertia coefficient of each converter. In addition, to avoid control hysteresis and adjustment error, a fast converter local control method based on model predictive approach is proposed to cooperate with the rapid inertia adjustment strategy. To verify the effectiveness of the proposed adaptive inertia control method based on model predictive approach, contrastive simulations are conducted using the proposed control strategy and the traditional control strategy separately based on MATLAB/Simulink. The results show that the proposed control method can effectively improve the transient response to disturbance of the system and guarantee the stability of DC bus voltage as well as the output power quality on AC side of grid‐connected converter. [ABSTRACT FROM AUTHOR]