Search Results (12)

To address the challenges of prolonged current isolation times and high dependency on varistors in traditional flexible short-circuit fault isolation schemes for DC systems, this paper proposes a rapid fault isolation circuit design based on an adaptive solid-state circuit breaker (SSCB). By introducing an adaptive current-limiting branch topology, the proposed solution reduces the risk of system oscillations induced by current-limiting inductors during normal operation and minimizes steady-state losses in the breaker. Upon fault occurrence, the current-limiting inductor is automatically activated to effectively suppress the transient current rise rate. An energy dissipation circuit (EDC) featuring a resistor as the primary energy absorber and an auxiliary varistor (MOV) for voltage clamping, alongside a snubber circuit, provides an independent path for inductor energy release after faults. This design significantly alleviates the impact of MOV capacity constraints on the fault isolation process compared to traditional schemes where the MOV is the primary energy sink. The proposed topology employs a symmetrical bridge structure compatible with both pole-to-pole and pole-to-ground fault scenarios. Parameter optimization ensures the IGBT voltage withstand capability and energy dissipation efficiency. Simulation and experimental results demonstrate that this scheme achieves fault isolation within 0.1 ms, reduces the maximum fault current-to-rated current ratio to 5.8, and exhibits significantly shorter isolation times compared to conventional approaches. This provides an effective solution for segment switches and tie switches in millisecond-level self-healing systems for both low-voltage (LVDC, e.g., 750 V/1500 V DC) and medium-voltage (MVDC, e.g., 10–35 kV DC) smart DC distribution grids, particularly in applications demanding ultra-fast fault isolation such as data centers, electric vehicle (EV) fast-charging parks, and shipboard power systems. Full article

The concept of more electric aircraft (MEA) has gained popularity over the last few decades. As the power level of electric loads is constantly increasing, the installation of advanced protection systems becomes of paramount importance. In this context, this paper presents the design process and experimental validation of a solid-state circuit breaker (SSCB), utilizing gallium nitride (GaN) semiconductor switches, under various faulty conditions. In addition, a thermal analysis was carried out in the PLECS simulation platform to find the most appropriate design for the heat dissipation system. Experimental results on the developed GaN SSCB hardware prototype verify its functionality and good performance. Full article

Energy routers act as an interface between the distribution network and electrical facilities, which meet the requirements of clean energy substitution and achieve the energy sharing and information transmission in the energy network. However, the protection of the dc load side of residential energy routers including interruption and isolation of short-circuit fault currents is vital for discussion. Since the traditional mechanical and hybrid circuit breakers for dc fault protection have the drawback of slow operation, a solid-state circuit breaker (SSCB) is an optimal solution for fast dc fault interruption. In this paper, a dc SSCB is proposed that uses an RCD + MOV snubber circuit, which is considered the best and most complete circuit used in common SSCBs. There are two main contributions in this paper: First, a dc SSCB is designed, which isolates both positive and negative terminals of a circuit and its working principle and operating modes along with the formulas for calculation of crucial time intervals, voltages, and currents along with the design procedure are provided. Second, a soft turn-on auxiliary is designed to prevent a high current surge caused by the capacitance difference between the source and the load. The experimental results demonstrate the proper performance of the topology and the validity of the findings. Full article

This paper deals with circuit breakers (CBs) used in direct current microgrids (DCMGs) for protection against electrical faults, focusing on their evolution and future challenges in low voltage (<1.5 kV) and medium voltage (between 1.5 kV and 20 kV). In recent years, proposals for new circuit-breaker features have grown. Therefore, a review on the evolution of circuit breakers for DCMGs is of utmost importance. In general terms, this paper presents a review concerning the evolution of circuit breakers used in DCMGs, focusing on fuses, mechanical circuit breakers (MCBs), solid-state circuit breakers (SSCBs), and hybrid circuit breakers (HCBs). Their evolution is presented highlighting the advantages and disadvantages of each device. It was found that although modern circuit breakers have begun to be commercially available, many of them are still under development; consequently, some traditional fuses and MCBs are still common in DCMGs, but under certain restrictions or limitations. Future challenges that would allow a successful and adequate implementation of circuit breakers in DCMGs are also presented. Full article

Ensuring a protection scheme in a DC distribution system is more difficult to achieve against pole-to-ground faults than in AC distribution system because of the absence of zero crossing points and low line impedance. To complement the major obstacle of limiting the fault current, several compositions have been proposed related to mechanical switching and solid-state switching. Among them, solid-state circuit breakers (SSCBs) are considered to be a possible solution to limit fast fault current. However, they may cause problems in circuit complexity, reliability, and cost-related troubles because of the use of multiple power semiconductor devices and additional circuit configuration to commutate the current. This paper proposes a SSCB with a coupled inductor (SSCB-CI) that has a symmetrical configuration. The circuit is comprised of passive components like commutation capacitors, a CI, and damping resistors. Thus, the proposed SSCB-CI offers the advantages of a simple circuit configuration and fewer utilized power semiconductor devices than the other typical SSCBs in the DC microgrid. For the analysis, six operation states are described for the voltage across the main switches and fault current. The effectiveness of the SSCB-CI against the short-circuit fault is proved via simulation and experimental results in a lab-scale prototype. Full article

Due to the working condition of low-voltage cabling from the mining flameproof movable substation to the loads of the mining face being poor, it is easy to cause various external mechanical damages to the cable sheaths. Furthermore, a single-phase earth leakage fault or short-circuit fault can occur when the low-voltage cable sheaths are damaged, and electric sparks caused by these faults can lead to a gas explosion. As the gas detonation time caused by the above faults is usually more than 5 ms, the high-speed interruption solid-state switch which controls the cables must cut off the current within 3 ms. This requires the action time of the solid-state switch to be less than 1 ms, and at the same time, the sampling and calculation time of the relay protection must be less than 2 ms. Based on these problems, this paper proposes the use of a high-speed solid-state circuit breaker (SSCB) topology at the neutral point of transformer, and analyzes the conduction mechanism and shut-off mechanism of the current of the SSCB. It presents an ultra-high-speed algorithm based on pattern recognition of single-phase earth leakage fault protection, and an ultra-high-speed algorithm of short-circuit fault which is based on the rate-of-change of the current. Finally, through computer simulation experiments and semi-physical simulation experiments, the feasibility of the above three technologies is verified to ensure that when a single-phase earth leakage fault or short-circuit fault occurs in the low-voltage cable, the solid-state switch which is installed in the mining flameproof movable substation will cut off the current within 3 ms. Full article

In this study, a low voltage solid-state circuit breaker (SSCB) was implemented for a DC distribution system using commercially available components. The design process of the high-side static switch was enabled through a voltage bias. Detailed functional testing of the current sensor, high-side switch, thermal ratings, analog to digital conversion (ADC) techniques, and response times of the SSCB was evaluated. The designed SSCB was capable of low-end lighting protection applications and tested at 50 V. A 15 A continuous current rating was obtained, and the minimum response time of the SSCB was nearly 290 times faster than that of conventional AC protection methods. The SSCB was implemented to fill the gap where traditional AC protection schemes have failed. DC distribution systems are capable of extreme faults that can destroy sensitive power electronic equipment. However, continued research and development of the SSCB is helping to revolutionize the power industry and change the current power distribution methods to better utilize clean renewable energy systems. Full article

This paper introduces a Solid State Circuit Breaker with Latching and Current Limiting capabilities for DC distribution systems. The proposed circuit uses very few electronic parts and it is fully analog. A SiC N-MOSFET driven by a photovoltaic driver and a maximum current detector circuit are the core elements of the system. This work details circuit operation under different conditions and includes experimental validation at 1 kVdc. Wide versatility, highly configurable, and very fast response, less than 1 µs in the case of short-circuit, are the most remarkable outcomes. Full article

Electric propulsion and integrated hybrid power systems can improve the energy efficiency and fuel consumption of different kinds of vessels. If the vessel power system is based on DC grid distribution, some benefits such as higher generator efficiency and lower volume and cost can be achieved. However, some challenges remain in terms of protection devices for this kind of DC grid-based power system. The absence of natural zero crossing in the DC current together with the fast and programmable breaking times required make it challenging. There are several papers related to DC breaker topologies and their role in DC grids; however, it is not easy to find comprehensive information about the design process of the DC breaker itself. In this paper, the basis for the design of a DC solid-state circuit breaker (SSCB) for low voltage vessel DC grids is presented. The proposed SSCB full-scale prototype detects and opens the fault in less than 3 µs. This paper includes theoretical analyses, design guidelines, modeling and simulation, and experimental results. Full article

Due to the lower on-state resistance, direct current (DC) solid state circuit breakers (SSCBs) based on silicon-carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) can reduce on-state losses and the investment of the cooling system when compared to breakers based on silicon (Si) MOSFETs. However, SiC MOSFETs, with smaller die area and higher current density, lead to weaker short-circuit ability, shorter short-circuit withstand time and higher protection requirements. To improve the reliability and short-circuit capability of SiC-based DC solid state circuit breakers, the short-circuit fault mechanisms of Si MOSFETs and SiC MOSFETs are revealed. Combined with the desaturation detection (DESAT), a “soft turn-off” short-circuit protection method based on source parasitic inductor is proposed. When the DESAT protection is activated, the “soft turn-off” method can protect the MOSFET against short-circuit and overcurrent. The proposed SSCB, combined with the flexibility of the DSP, has the μs-scale ultrafast response time to overcurrent detection. Finally, the effectiveness of the proposed method is validated by the experimental platform. The method can reduce the voltage stress of the power device, and it can also suppress the short-circuit current. Full article

Silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) have the advantages of high-frequency switching capability and the capability to withstand high temperatures, which are suitable for switching devices in a direct current (DC) solid state circuit breaker (SSCB). To guarantee fast and reliable action of a 400 V DC SSCB with SiC MOSFET, circuit design and prototype development were carried out. Taking 400V DC microgrid as research background, firstly, the topology of DC SSCB with SiC MOSFET was introduced. Then, the drive circuit of SiC MOSFET, fault detection circuit, energy absorption circuit, and snubber circuit of the SSCB were designed and analyzed. Lastly, a prototype of the DC SSCB with SiC MOSFET was developed, tested, and compared with the SSCB with Silicon (Si) insulated gate bipolar transistor (IGBT). Experimental results show that the designed circuits of SSCB with SiC MOSFET are valid. Also, the developed miniature DC SSCB with the SiC MOSFET exhibits faster reaction to the fault and can reduce short circuit time and fault current in contrast with the SSCB with Si IGBT. Hence, the proposed SSCB can better meet the requirements of DC microgrid protection. Full article

Circuit breakers (CBs) are the main protection devices for both alternating current (AC) and direct current (DC) power systems, ranging from tens of watts up to megawatts. This paper reviews the current status for solid-state circuit breakers (SSCBs) as well as hybrid circuit breakers (HCBs) with semiconductor power devices. A few novel SSCB and HCB concepts are described in this paper, including advantage and limitation discussions of wide-band-gap (WBG) devices in basic SSCB/HCB configuration by simulation and 360 V/150 A experimental verifications. Novel SSCB/HCB configurations combining ultra-fast switching and high efficiency at normal operation are proposed. Different types of power devices are installed in these circuit breakers to achieve adequate performance. Challenges and future trends of semiconductor power devices in SSCB/HCB with different voltage/power levels and special performance requirements are clarified. Full article