This paper investigated a cascaded pulsed load power supply (PLPS) with optimized control schemes for pulsed power loads (PPLs). The first stage of the PLPS is a phase-shifted full-bridge converter (PSFB) to provide the average power for PPL. A buck converter is selected for the second stage to facilitate the pulsed load current. The cascaded PLPSs usually select a buck converter at the second stage, while the second-stage buck converter's input impedance acts as a negative resistor that leads the cascaded system to instability. Therefore, a series virtual impedance (SVI) based optimization is utilized to improve the system stability, and an output current feedforward path is added to the control loop of the fast response-stage to raise the load tracking speed. Moreover, to reduce the system input current fluctuations and overcome the PSFB converter's slow response and bandwidth limitation, an I2 average current control is used. An experimental-based analysis is performed to confirm the validity of the control scheme. The results on the prototype of cascaded PLPS with 784 W peak and 117.6 W average powers, 100 V input voltage, 28 A output pulsed current, and a pulse repeating frequency (PRF) of 100-300 Hz validated that the proposed optimization scheme outperforms other leading available schemes.

To address the efficiency loss caused by the need for an additional central converter in traditional photovoltaic-isolated port (PV-IP) architecture, the concepts of differential power processing (DPP) and series-connected partial power processing are introduced, and then, a multi-degree-of-freedom DPP (MF-DPP) architecture for photovoltaic (PV) systems is proposed. In the proposed architecture, the auxiliary converter is introduced to be paralleled with the DPP converters and connected in series with the PV modules so that the bus port can directly connect the loads with specific voltage requirements and the efficiency of the entire system can be improved. A control algorithm for the new architecture is also proposed, which can simultaneously achieve maximum power point tracking (MPPT) for PV modules and least power point tracking (LPPT) for the total power processed by the DPP converters. Finally, a PV system experimental platform is built to verify the effectiveness of the proposed architecture and control algorithm. The experimental results show that the proposed architecture can effectively improve the system efficiency under mismatched power conditions.

This paper proposes a virtual inertia control strategy of electro-methanol production system for frequency support, aiming to address the problem of instability in power systems when electro-methanol production system is connected to the grid. First, the concept of virtual rotational inertia is explained based on the operating characteristics of electro-methanol production system. Next, different operating modes are defined according to the impact of various grid disturbances on the power system. Besides, provide inertia support for the grid while ensuring efficient methanol production, specific control methods are proposed for different operating modes: efficient methanol production under no-disturbance conditions, and rapid inertia support to the grid under disturbance conditions. MATLAB/Simulink software and the hardware-in-the-loop (HIL) testing method are used to simulate and verify the proposed strategy under different disturbance scenarios. Results show that the proposed control strategy can quickly respond to grid disturbances and provide inertia support under various disturbance conditions.

Asymmetric Duty Modulation (ADM) opens up new opportunities for DAB converter to improve steady-state performance. Triple phase shift (TPS) modulation, which belongs to symmetric duty modulation (SDM), can minimize the inductor RMS current. However, the soft-switching range is still limited at light load. A unilateral asymmetric triple phase shift (UATPS) modulation strategy combining ADM and SDM is proposed in this paper to reduce the RMS inductor current while expanding soft-switching range. Firstly, typical waveforms of UATPS are generated by combining ADM and SDM, and the steady-state characteristics are derived in time domain. Secondly, a mathematical model for optimization is established, and the global optimal solution is obtained based on the Karush-Kuhn-Tucker (KKT) condition, and the direct power control strategy of the UATPS is proposed. Finally, the experimental results verify the effectiveness of UATPS to improve the efficiency.

In order to deal with the problem of three-level oscillations and improper perturbation of common algorithm in photovoltaic (PV) system. We propose a staggered-phase off-oscillation photovoltaic LMPPT algorithm for suppressing the improper-perturbation. We stagger the perturbation time to forbid PV modules disturb simultaneously, applying Perturbation and Observation (P&O) in maximum power point tracking (MPPT) and least power point tracking (LPPT) control algorithm and maintain the intermediate level of three-level oscillation. It solves the problem of mutual interference of multi-modules during the perturbation process, finding the optimum operating point quickly and eliminates the three-level oscillation. Finally, experimental prototype is set up, all experimental results demonstrate the feasibility and advantage of our algorithm.

港口再生资源丰富,新能源接入港口岸电系统的研究对于响应"绿色港口"建设和提高新能源消纳比例具有重要意义.为此,文中提出一种直流微网式新能源港口岸电系统.首先,分别建立光伏发电系统、风力发电系统、储能系统和市电系统仿真模型,并详细介绍各系统的工作原理与控制方法;然后,为提高新能源进入港口岸电系统比例,提出一种新能源岸电系统能量调控策略;最后,通过仿真验证其在孤岛模式与并网模式下的功能.结果表明,所提系统具有较强的动静态性能,能够满足船舶负载的功率需求.

The power supply and distribution system of airborne mission equipment must maintain high reliability and high power quality under any working conditions.However,with the widespread use of high-power nonlinear electrical equipment,generator voltage and current waveforms can become distorted,resulting in power quality degradation.In addition,problems often occur in areas such as compatibility of the airborne power supply system with electrical equipment.In view of these problems,this paper briefly describes the development and classification of the output categories of airborne power supply systems,summarizes the scheme design of power distribution architecture and rectification technology for electrical equipment,elucidates the contents and interrelationships of power supply adaptability characteristic standards,testing standards,and testing method standards,clarifies the adaptability design principles of the electrical equipment,and analyzes the advantages and disadvantages of pulse load power matching solutions for airborne generators,which provides some important guiding roles for the design and testing of the new generation airborne power supply systems and electrical equipments.

In order to develop green ports and reduce carbon emissions, it is advocated that ships should actively use shore power during berthing. Therefore, in order to meet the seamless grid-connected requirements of power systems on both sides of the ship and shore and stable and reliable operation of ship loads when the ship and shore are connected to the grid, this paper proposes a control strategy based on the combination of virtual synchronous generator (VSG) technology and grid-connected pre-synchronization control technology, but not coupled, to achieve seamless connection of the ship and shore and meet the stable and reliable operation of ship loads.

The shore power technology of ships refers to stop using diesel generators during berthing, and the ships are powered by shore power, which plays the role of energy saving and emission reduction, so it is important to study how to promote the shore power technology of ports. Firstly, the necessity of port shore power promotion is introduced, secondly, the main difficulties of shore power technology promotion are analyzed with the examples of domestic ports, among which the economic benefits are evaluated through cost analysis of various types of ports, and finally, specific initiatives for port shore power promotion and application are proposed.

This paper analyses the evolution of urban spatial structure from the perspective of regional culture, aiming at analyzing the interaction between regional culture and urban spatial structure, and putting forward optimization suggestions for urban spatial development in Wenchuan disaster reconstruction area.