DC microgrid has attracted more and more attention due to its unique characteristics, but the development of DC microgrid is also facing some challenges, such as interruption and isolation of short circuit fault currents. Therefore, DC circuit breaker plays an important role in ensuring the normal work of DC microgrid. In this paper, a novel bidirectional DC solid-state circuit breaker is proposed to realize the bidirectional flow of energy, which ensures the higher operating efficiency of the DC microgrid. Compared with other solid-state circuit breakers, the proposed novel topology has simpler structure, common ground and fewer components. Firstly, this paper makes a detailed analysis of the different working stages of the circuit when the fault occurs in combination with simulation results of the circuit topology. Then, the standard of selecting the components through the calculation and analysis of the circuit is given in this paper. Finally, the performance of the novel bidirectional solid-state circuit breaker is verified by experiments.

The development of the DC microgrid system on-board has promoted the development of the DC circuit breaker, due to that the short circuit fault may cause serious damage to the system. However, the traditional DC circuit breaker exists many problems such as long period of fault interruption, complex circuit structure, existing arc, low reliability and low anti-interference. Aiming to solve these problems, a novel solid-state DC circuit breaker was proposed in this paper. Firstly, this paper analyzes the working principle and process of the circuit in detail according to the results of the simulation based on Saber. Secondly, this paper gives the criteria on how to choose the parameters of the components correctly in the circuit. The concept of the maximum fault resistance according to the minimum fault current is also introduced. Moreover, this paper analyzes the influence of the minimum fault ramp rate on the circuit performance. Finally, experimental results verify that the performance of this novel solid-state circuit breaker agree with theoretical analysis.

DC microgrids have attracted increasing attention due to their high efficiency, simple control, and high power quality; however, circuit fault protection remains a technical challenge. Z-source circuit breakers (ZSCBs) have provided a promising solution with fast, autonomous, and arcless fault clearances. To further provide bidirectional operation capability and enhanced performance, a bidirectional ZSCB based on coupled inductors is proposed and well designed in this article. It can offer bidirectional power flow and fault disconnections in a compact size. The working principle and circuit analysis are elaborated with mathematical models, which cover the entire fault-clearing transient and can provide insightful guidelines for breaker design and component sizing. Moreover, a crowbar-type switch enabling manual tripping operation of the proposed ZSCB is integrated. Finally, Saber-based simulations verify the effectiveness of the models and the design, which are further validated by a 48 V/230 W laboratory prototype.

Silicon-controlled rectifier-based dc solid-state circuit breakers (SCR-SSCBs) have received an increased attention for their ease of control and high efficiency, but their considerable conduction losses remain a major disadvantage. This article presents a new bidirectional SCR-SSCB topology, which reduces the conduction losses by ∼50%, with the loss reduction attributed to an inductor being eliminated from the main circuit during normal operation. This is achieved by conducting current through one semiconductor switch instead of two as in the conventional devices. In addition, the presented topology enhances the reliability of protection by enabling a controlled interruption of short-circuit faults in which fault interruption is not affected by the parameters of external systems to which the circuit breaker is connected to. A second topology that reduces the size of the capacitors in the commutating circuit is also introduced. A detailed analysis of the operating principle of the two novel topologies is presented. Recommendations supported by mathematical modeling are provided for selecting the relevant components of the devices. The performance of the two topologies was verified through simulation and experimental tests.

DC microgrids have attracted more and more attention with its universality, high efficiency and potential application market. However, DC fault protection is still a challenge to the development of DC microgrids. In this paper, a novel bidirectional DC solid-state circuit breaker based on coupled inductor is introduced. It can realize bidirectional energy flow and bidirectional isolation and interruption of short-circuit faults with fewer components. The working principle of the topology and the working process under different conditions are described, and some properties of the novel circuit breaker are explored, including minimum fault current ramp rate and load step analysis, which provides a reference for the selection of component parameters. Finally, the feasibility and performance of the novel bidirectional circuit breaker is evaluated by simulations and experiments.

More-electric aircraft (MEA) has evolved in the recent two decades owing to their superiority in fuel efficiency, noise reduction, and reliability compared to conventional aircraft. The power supply systems, commonly regarded as distributed interactive systems, play a paramount role in MEA, yet are facing critical concerns in terms of their stability. Impedance is a key enabling tool to study the stability of such interactive systems and therefore contributes to better design optimization. Toward this end, this paper presents a comprehensive review of the impedance modeling, stability analysis, and impedance shaping for power supply system in MEA. The three typical power supply system architectures of MEA are introduced and summarized in the first place. Then, existing studies on impedance model are reviewed. Due to the nonlinear time-varying characteristics of the AC system, it needs to be linearized. This paper discusses the characteristics and scope of applications of dq -axis linearization and harmonic linearization methods. Besides, this paper highlights the aspects of the impedance stability analysis including DC and AC stability criterion. The strengths, limitations and application scenarios of each criterion are summarized and discussed. Finally, impedance shaping methods, including structural reshaping, impedance parameter optimization, and system-level control, have also been surveyed and summarized.