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John Z Shen - One of the best experts on this subject based on the ideXlab platform.

  • a 400v 300a ultra fast intelligent dc solid state Circuit breaker using parallel connected sic jfets
    European Conference on Cognitive Ergonomics, 2019
    Co-Authors: Wei Wang, Jinyong Lei, Zhikang Shuai, Dong He, Ying Cheng, Xue Yang, John Z Shen
    Abstract:

    The increasing load density of direct current (DC) distribution system leads to an increase in system capacity and Short-Circuit fault current. However, due to the limited capacity of a single semiconductor device, solid state Circuit breaker (SSCB) with one semiconductor device is difficult to apply to high current applications. This paper proposes a 400V/300A intelligent SSCB with 8 parallel normally-on SiC JFETs as the main static switch, a Microprocessor Unit (MCU) as the intelligent controller and a fast-starting isolated DC/DC converter as the Protection driver. This article focuses on Current sharing and balancing among the parallel SiC JFETs. The Short Circuit experiment was performed using the designed SSCB prototype. The experimental results show that the proposed SSCB can realize Short-Circuit Protection in several microseconds and overload Protection in several hundred microseconds. In addition, good dynamic and static current sharing effect is achieved in this paper.

  • A SiC JFET-Based Solid State Circuit Breaker With Digitally Controlled Current-Time Profiles
    IEEE Journal of Emerging and Selected Topics in Power Electronics, 2019
    Co-Authors: Dong He, Zhiqi Lei, Zhikang Shuai, Xue Yang, Wei Wang, John Z Shen
    Abstract:

    DC distribution networks are able to effectively improve the energy efficiency and easy integration of distributed generations. However, the reliable dc Circuit breaker is an essential requisite for the wide application of dc power. This paper proposes a self-powered solid-state Circuit breaker (SSCB) with a digitally controlled current-time profile for both ultrafast Short-Circuit Protection and overcurrent Protection. The fault detection unit detects Short-Circuit or overcurrent conditions by sensing the sampling resistance voltage and delivers these voltage signals to a low-cost microprocessor to realize the Protection operation of the SSCB. A pulsewidth modulation (PWM) current limiting Protection method with time interval Td is proposed to avoid nuisance tripping caused by inrush current during power electronic load startup. The time interval is properly selected based on the transient thermal properties of silicon carbide (SiC) junction gate field-effect transistors (JFETs). In order to verify the dynamic response of the SSCB, a SiC JFET-based Circuit breaker prototype is designed and fabricated for result confirmation.

  • A Digital-Controlled SiC-Based Solid State Circuit Breaker with Soft-Start Function for DC Microgrids
    2018 9th IEEE International Symposium on Power Electronics for Distributed Generation Systems (PEDG), 2018
    Co-Authors: Yuanfeng Zhou, Tianjiao Liu, Yanjun Feng, John Z Shen
    Abstract:

    This paper introduces a digital-controlled, SiC MOSFET based, autonomously operated 380V/20A solid state Circuit breaker (SSCB) that features a soft start function in addition to basic Short Circuit Protection function. The SSCB offers three distinct operation states: ON, OFF, and PWM Current Limiting (PWM-CL). While the conventional ON/OFF states allow the SSCB to conduct normal load currents or interrupt fault currents, the PWM -CL state allows the SSCB to gradually charge the input capacitors of electronic loads at a limited current level during load startup. The SSCB can switch from the PWM-CL state to the OFF state if a true Short Circuit fault is detected. In the PWM -CL state, a variable frequency PWM control technique is proposed to optimally operate a buck converter for soft start and Short fault detection. The controller design of the new SSCB combines the flexibility of a DSP with the μs-scale ultrafast response time of an analog-like overcurrent detection Circuit. The paper analyzes the relationship between the PWM frequency and Circuit parameters, load voltage, and load resistor. The new SSCB is prototyped and experimentally verified.

  • SiC solid state Circuit breaker with an adjustable current-time tripping profile
    2018 IEEE Applied Power Electronics Conference and Exposition (APEC), 2018
    Co-Authors: Yanjun Feng, Yuanfeng Zhou, John Z Shen
    Abstract:

    This paper reports a SiC-based solid-state Circuit breaker (SSCB) with an adjustable current-time (I-t) tripping profile for both ultrafast Short Circuit Protection and overload Protection. The tripping time ranges from 0.5 microsecond to 10 seconds for a fault current ranging from 0.8X to 10X of the nominal current. The I-t tripping profile, adjustable by choosing different resistance values in the analog control Circuit, can help avoid nuisance tripping of the SSCB due to inrush transient current. The maximum thermal capability of the 1200V SiC JFET static switch in the SSCB is investigated to set a practical thermal limit for the I-t tripping profile. Furthermore, a low fault current `blind zone' limitation of the prior SSCB design is discussed and a new Circuit solution is proposed to operate the SSCB even under a low fault current condition. Both simulation and experimental results are reported.

  • Ultrafast autonomous solid state Circuit breakers for shipboard DC power distribution
    2015 IEEE Electric Ship Technologies Symposium (ESTS), 2015
    Co-Authors: John Z Shen, Zhenyu Miao, Aref Moradkhani Roshandeh, Gourab Sabui
    Abstract:

    Short Circuit Protection remains one of the major technical barriers in DC power systems. This paper introduces a new concept of ultrafast autonomous SSCBs. The new SSCB comprises one or more normally-on WBG transistor as the main static switch and a fast-starting isolated DC/DC converter as the Protection driver. It detects Short Circuit faults by sensing its drain-source voltage rise, and draws power from the fault condition itself to turn and hold off the switch. Prototypes experimentally demonstrate repeated interruption of fault currents up to 180 amperes at a DC bus voltage of 400 volts within 0.8 μs. A method to extend this concept to higher bus voltages is also proposed and verified with PSPICE simulation. A hybrid Protection strategy, which combines protective power converters, autonomous SSCBs, and networked SSCBs, is proposed for shipboard DC power architectures.

Vikas Singh - One of the best experts on this subject based on the ideXlab platform.

  • Future Shipboard MVdc System Protection Requirements and Solid-State Protective Device Topological Tradeoffs
    IEEE Journal of Emerging and Selected Topics in Power Electronics, 2017
    Co-Authors: Robert M Cuzner, Vikas Singh
    Abstract:

    The search for the optimum architecture for shipboard medium voltage dc\nintegrated power systems must take into account the Short-Circuit\nProtection in addition to overarching goals of efficiency,\nsurvivability, reliability of power, and cost effectiveness. Presently,\naccepted approaches to Protection are ``unit-based,{''} which means the\npower converter(s) feeding the bus coordinate with no-load\nelectromechanical switches to isolate faulted portions of the bus.\nHowever, ``breaker-based{''} approaches, which rely upon solid-state\nCircuit breakers for fault mitigation, can result in higher reliability\nof power and potentially higher survivability. The inherent speed of\noperation of solid-state protective devices will also play a role in\nfault isolation, hence reducing stress level on all system components. A\ncomparison study is performed of protective device topologies that are\nsuitable for shipboard distribution systems rated between 4 and 30 kVdc\nfrom the perspectives of size and number of passive components required\nto manage the commutation energy during sudden fault events and\npackaging scalability to higher current and voltage systems. The\nimplementation assumes a multichip silicon carbide (SiC) 10-kV, 240-A\nMOSFET/junction barrier Schottkey (JBS) diode module.

  • converter topological and solid state protective device trade offs for future shipboard mvdc systems
    Electric Ship Technologies Symposium, 2015
    Co-Authors: Robert M Cuzner, Vikas Singh, Mohammad Rashidi, Adel Nasiri
    Abstract:

    The search for the optimum architecture for Medium Voltage DC (MVDC) Integrated Power Systems must take into account the Short Circuit Protection in addition to overarching goals of efficiency, survivability and cost effectiveness. A comparison study is performed for architectures with a suitable combination of protective devices and power conversion. This leads also to an optimum MVDC bus voltage somewhere between 15kVdc and 20kVdc. Hardware implementation using packaged SiC devices, currently under development, is explored. The inherent speed of operation of Solid state protective devices will also play a role in fault isolation, hence reducing stress level on all system components.

Yaowen Dong - One of the best experts on this subject based on the ideXlab platform.

  • a digital controlled sic based solid state Circuit breaker with soft switch off method for dc power system
    Electronics, 2019
    Co-Authors: Haihong Qin, Yubin Mo, Qian Xun, Ying Zhang, Yaowen Dong
    Abstract:

    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.

Robert M Cuzner - One of the best experts on this subject based on the ideXlab platform.

  • Future Shipboard MVdc System Protection Requirements and Solid-State Protective Device Topological Tradeoffs
    IEEE Journal of Emerging and Selected Topics in Power Electronics, 2017
    Co-Authors: Robert M Cuzner, Vikas Singh
    Abstract:

    The search for the optimum architecture for shipboard medium voltage dc\nintegrated power systems must take into account the Short-Circuit\nProtection in addition to overarching goals of efficiency,\nsurvivability, reliability of power, and cost effectiveness. Presently,\naccepted approaches to Protection are ``unit-based,{''} which means the\npower converter(s) feeding the bus coordinate with no-load\nelectromechanical switches to isolate faulted portions of the bus.\nHowever, ``breaker-based{''} approaches, which rely upon solid-state\nCircuit breakers for fault mitigation, can result in higher reliability\nof power and potentially higher survivability. The inherent speed of\noperation of solid-state protective devices will also play a role in\nfault isolation, hence reducing stress level on all system components. A\ncomparison study is performed of protective device topologies that are\nsuitable for shipboard distribution systems rated between 4 and 30 kVdc\nfrom the perspectives of size and number of passive components required\nto manage the commutation energy during sudden fault events and\npackaging scalability to higher current and voltage systems. The\nimplementation assumes a multichip silicon carbide (SiC) 10-kV, 240-A\nMOSFET/junction barrier Schottkey (JBS) diode module.

  • converter topological and solid state protective device trade offs for future shipboard mvdc systems
    Electric Ship Technologies Symposium, 2015
    Co-Authors: Robert M Cuzner, Vikas Singh, Mohammad Rashidi, Adel Nasiri
    Abstract:

    The search for the optimum architecture for Medium Voltage DC (MVDC) Integrated Power Systems must take into account the Short Circuit Protection in addition to overarching goals of efficiency, survivability and cost effectiveness. A comparison study is performed for architectures with a suitable combination of protective devices and power conversion. This leads also to an optimum MVDC bus voltage somewhere between 15kVdc and 20kVdc. Hardware implementation using packaged SiC devices, currently under development, is explored. The inherent speed of operation of Solid state protective devices will also play a role in fault isolation, hence reducing stress level on all system components.

Juan C Vasquez - One of the best experts on this subject based on the ideXlab platform.

  • overload and Short Circuit Protection strategy for voltage source inverter based ups
    IEEE Transactions on Power Electronics, 2019
    Co-Authors: Baoze Wei, Albert Marzabal, Jose Perez, Ramon Pinyol, Josep M Guerrero, Juan C Vasquez
    Abstract:

    In this paper, an overload and Short-Circuit Protection method is proposed for voltage source inverter-based uninterruptible power supply (UPS) system. In order to achieve high reliability and availability of the UPS, Short Circuit and overload Protection scheme are necessary. When overload or Short Circuit happens, using the proposed control method, the amplitude of the output current can be limited to a constant value, which can be set by the customer to avoid the destruction of the power converter, and to obtain a faster recovery performance as well. The detailed principle of the proposed Protection method is discussed in this paper. It mainly contains three parts in the control diagram for current limit, first is the anti-windup in the voltage and current controllers, then the feedforward of the capacitor voltage to the current control loop, the last is the fast reset of the resonant part of the current controller when overcurrent happens. The procedure of developing the control method is also presented in the paper. Experimental results on a commercial UPS system are presented to verify the effectiveness of the control method.