This paper proposes a high-power-density DC-bus power pulsation decoupling module to address the instantaneous power imbalance issue between DC-side and AC-side of the single-phase inverter. The Dual-Buck buffer effectively prevents shoot-through problem of the bridge caused by false triggering of GaN FET. Additionally, this paper introduces a voltage control scheme based on interpolation predictor to compensate for control delay and to improve impedance characteristics of the power pulsation decoupling module, make it closer to that of electrolytic capacitors. The proposed active decoupling scheme employs long-life and highly reliable ceramic capacitors instead of conventional electrolytic capacitors, with the capacitance being theoretically optimized, and an impedance model being established to guide the design. A 2000W experimental prototype is built to validate the circuit performance.

To improve the power flow regulation ability and power supply reliability of the distribution network, flexible interconnection device(FID) is introduced into the distribution network, and a self-synchronous voltage source (SSVS)-based FID control method is proposed. At first, a back-to-back FID mathematical model is established, and three operating modes of the system are analyzed. Traditional control methods (TCM) and SSVS control methods of FID are introduced and compared. This proposed strategy formulates power dispatch instructions based on the power flow and load condition data of the interconnected substations, achieving load balancing and stable control of load transfer. It avoids the shortcomings of traditional PI parameter control methods, which require switching control strategies for multi-mode operation and have difficulties in tuning. Furthermore, proposed SSVS strategy has the ability to participate in power grid frequency modulation. Finally, a FID simulation model is constructed in the MATLAB/Simulink, and the effectiveness of the proposed control strategy is verified by simulation under typical operation conditions.

With the development of renewable energy power generation, the neutral point clamped three-level inverter has gained widespread application, due to its advantages such as low device stress and output characteristics. However, due to the different working styles of the power switches, there are significant differences in losses and thermal stresses. The active neutral point clamped three-level topology provides more freewheeling paths for grid-in current, which allows for changing the working styles of switches. Thus, it offers the structural foundation for optimizing the loss distribution and thermal stresses. Furthermore, it is still necessary to employ novel modulation strategies to balance the losses. For this purpose, a novel modulation strategy with a more balanced loss distribution is proposed for active neutral point clamped gridconnected inverter in this paper. Two traditional modulation strategies are overviewed in brief. Based on the commutating process and the switching losses distribution in the conventional modulation strategies, the commutating paths are combined in the novel modulation strategy. The comparison between the proposed modulation strategy and the traditional modulation strategies is conducted by numerical calculation. The results demonstrate the performance in achieving a balanced loss distribution by the proposed strategy. Furthermore, experimental validation is performed to verify the effectiveness of the proposed modulation strategy.

The strength of a renewable-dominated power system fluctuates over a wide range. The synchronous voltage source (SVS) has the proven ability to actively support weak power grids and has been put into practical application. However, when the SVS with voltage and current closed-loop control is connected to a strong grid, it faces oscillation problems. This paper proposes a method to reshape the voltage controller, realizes the impedance-reshaping of the converter, and enhances the stability of the inverter when it is connected to a strong grid. The simulation results verify the effectiveness of the method.