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A new series-type hybrid circuit breaker (S-HCB) concept for dc fault protection is reported that is fundamentally different from other prior-art hybrid circuit breakers (HCB) or solid-state circuit breakers (SSCB) in the literature. The S-HCB conducts its load current through metal wires instead of power semiconductor switches and curtails its fault current to near zero throughout the entire opening process of a series mechanical switch. It offers the low on-resistance of the conventional mechanical contacts for normal operation and µs-scale fault response even faster than the fast-acting SSCBs. A proof-of-concept S-HCB prototype experimentally demonstrates the interruption of a fault current of 30 A within 10 μs at a dc voltage of 600 V. The operating principle, simulation, and experimental results are discussed in this letter. [ABSTRACT FROM AUTHOR]

Hybrid dc circuit breakers (HCBs) are recognized as suitable devices for protecting high-voltage direct-current (HVDC) systems, along with other dc circuit breakers (DCCB). However, compared to mechanical circuit breakers, HCBs exhibit higher conduction losses. Such losses are inevitable under no-fault conditions as current may flow through some of the semiconductor switches. An integrated circuit breaker (ICB) minimizing these losses is presented in this paper, and this is achieved by replacing semiconductor switches by mechanical components in the current path. For completeness, the topology design, operating sequence and a mathematical analysis for component sizing of the device are provided. In addition, an estimation of the conduction losses is quantified. It is estimated that the power losses of an ICB are 2 to 30% of an HCB only. The ICB has been implemented in PSCAD/EMTDC to demonstrate its effectiveness for isolating dc faults, with simulations conducted on a three-terminal HVDC grid. [ABSTRACT FROM AUTHOR]

Long pulse gas lasers utilizing double-discharge circuits are different from the single-short pulse gas lasers in that they do not require all of the desired energy to be deposited into the peaking capacitors prior to ignition of the main gap. Instead, the majority of the energy is held in another capacitor that is then discharged in the form of a longer duration discharge pulse output compared with that of single-short pulse lasers. Extended stability of the discharge is typically achieved by igniting the main gap discharge at higher ignition voltages. Several double-discharge circuit topologies exist in the literature. However, each topology has its own disadvantages primarily centered around the components needed and the resulting complexity. In this article we introduce the application of the new hybrid circuit pulsed power topology as a double-discharge circuit with high ignition voltages. The hybrid circuit pulsed power topology was originally published by the authors of this article in their previous publication titled “A New Hybrid Pulsed Power Circuit Topology for Gas Laser Applications.” The advantage of the hybrid circuit as a double-discharge circuit is that it does not require any special device [e.g., semiconductor opening switch (SOS) diode] and can use commonly available components. [ABSTRACT FROM AUTHOR]

This article presented a new hybrid circuit breaker solution for using in dc microgrids. The proposed solution can offer a high-reliability protection feature for the dc microgrid with low conduction loss, bidirectional current flow, and galvanic isolation function. In the design, it is combined with a group of mechanical switches and semiconductors, where the mechanical switches handle the current conduction during normal operation and the semiconductors handle the breaker response during transient operation. The design fully utilizes the advantage of both types of switches and maximizes the performance and life time of the system. Throughout the design, it maintains only one mechanical switch in series with each power line; thereby, the high conductivity of the circuit breaker is maintained. At the same time, through the hybrid design, the electrical stress applied to the mechanical switch is eliminated. Thus, an effective and high-reliability solution is provided for the design of dc circuit breakers. The operation principle is explained in detail and the design guideline is provided. A 150/380 V and 15 A circuit breaker is successfully implemented, and the performance is experimentally verified, which shows good agreement with the theoretical findings. [ABSTRACT FROM AUTHOR]

Hybrid dc circuit breaker (HCB) is currently the most promising dc circuit breaker. However, since it requires hundreds of semiconductor switches to withstand high transient interruption voltage, the implementation cost is high. Besides, in the multiterminal dc grid, three or more HCBs may be required at a dc bus, which worsens the disadvantages of HCBs in economy and volume. In order to solve this problem, this article designs a diode-bridge multiport HCB (DB-MPB) with its control procedures. By integrating the n HCBs at the dc bus to a single n-port HCB, the number of semiconductor switches and the footprint can be reduced, while the good current interruption performance can be still maintained. Besides, for the possibility of ultrafast disconnector (UFD) failure, the proposed DB-MPB has the function of UFD failure protection. The effectiveness of the designed DB-MPB under different scenarios is verified by simulations and experimental tests. In addition, the performance comparisons in economy and functionality of the proposed DB-MPB with existed solutions are presented to highlight the advantages of the proposed solution. [ABSTRACT FROM AUTHOR]

Direct current (DC) circuit breakers are a key enabling technology for fault management in multiterminal highvoltage DC (HVDC) systems. DC fault isolation is challenging due to the high rate of rise of the fault current and the lack of natural current zero-crossings found in ac systems. In this paper, we present a novel superconducting hybrid dc circuit breaker that utilizes the intrinsic characteristics of the superconductor material. The automatic quench of the superconductor coil as a result of a high fault current transfers the current from the mechanical switch to the semiconductor switch. The isolating mechanical switch is able therefore to open at low current and recover its dielectric capability rapidly. A low voltage DC circuit breaker prototype has been built using a multistrand magnesium diboride (MgB2 ) coil, a vacuum interrupter, and an insulated-gate bipolar transistor module. This prototype successfully demonstrated interruption of 500 A DC within 4.4 ms. This paper presents the design of the superconducting hybrid breaker prototype and a detailed analysis of the experimental results. This superconducting hybrid dc circuit breaker has significant potential for scaling up the high-voltage and high-current applications. [ABSTRACT FROM AUTHOR]

The ultra-fast switching of power MOSFETs, in about 1 ns, is very challenging. This is largely due to the parasitic inductance that is intrinsic to commercial packages used for both MOSFETs and drivers. Parasitic gate and source inductance not only limit the voltage rise time on the MOSFET internal gate structure but can also cause the gate voltage to oscillate. This paper describes a hybrid approach that substantially reduces the parasitic inductance between the driver and MOSFET gate, as well as between the MOSFET source and its external connection. A flip-chip assembly is used to directly attach a die-form power MOSFET and driver on a PCB. The parasitic inductances are significantly reduced by eliminating bond wires and minimizing lead length. The experimental results demonstrate ultra-fast switching of the power MOSFET with excellent control of the gate-source voltage. [ABSTRACT FROM AUTHOR]