Abstract: In one aspect, a method of managing a participation of a virtual power plant (VPP) comprising a plurality of electric vehicle supply equipment (EVSE) in an ancillary service market for an electric grid is provided. The method comprises generating a bid for participating in the ancillary service marked over a time period, transmitting the bid to the ancillary service market, receiving a response from the ancillary service market indicating that the bid was accepted, and identifying a request from the ancillary service market for the VPP to provide grid support to the electric grid during the time period. The method further comprises generating, based on the bid and in response to the request, at least one charging profile for one or more of the EVSEs, and providing the at least one charging profile to the one or more of the EVSEs to implement the request for grid support.

Abstract: In one aspect, a fuel cell power system is provided. The fuel cell power system includes a ring bus, a plurality of bidirectional uninterruptible power supplies (UPSs), a plurality of direct current (DC) fuel cell modules, and a plurality of bidirectional direct current to alternating current (DC-AC) power converters. Each of the plurality of UPSs is electrically coupled to at least one battery, an AC utility feed, a load, and via a choke, the ring bus. Each of the plurality of DC fuel cell modules includes one or more fuel cells coupled to a hydrogen storage. Each of the plurality of bidirectional DC-AC power converters is electrically coupled to a corresponding one of the plurality of DC fuel cell modules and a corresponding one of the plurality of bidirectional UPSs at the AC utility feed.

Abstract: In one aspect, a fuel cell power system is provided. The fuel cell power system includes a ring bus, a plurality of bidirectional uninterruptible power supplies (UPSs), a plurality of direct current (DC) fuel cell modules, and a plurality of bidirectional direct current to alternating current (DC-AC) power converters. Each of the plurality of UPSs is electrically coupled to at least one battery, an AC utility feed, a load, and via a choke, the ring bus. Each of the plurality of DC fuel cell modules includes one or more fuel cells coupled to a hydrogen storage. Each of the plurality of bidirectional DC-AC power converters is electrically coupled to a corresponding one of the plurality of DC fuel cell modules and a corresponding one of the plurality of bidirectional UPSs at the AC utility feed.

Abstract: A method for determining a charging price for an electric charging site includes receiving time tags and data obtained based on automated metering infrastructure (AMI) data for the electric charging site, and weather information for a service area of the electric charging site; clustering power consumption of the electric charging site with similar weather information and time tags; calculating a center of mass and a distribution confidence parameter for the clustered power consumption to obtain a look-up table; retrieving historical information of voltage VPCC and injection power Psite pairs that is measured at a point of common coupling (PCC) of the electric charging site; receiving weather forecast information for the service area of the electric charging site; and calculating a dynamic hosting capacity (DHC) curve and a price curve based on the center of mass and the distribution confidence parameter, the VPCC and Psite pairs, and the weather forecast information.

Abstract: A system includes: a ring bus; a plurality of static uninterruptible power supplies (UPSs), each static UPS of the plurality of static UPSs including: at least one battery; an input that is electrically connected to a first external electrical power source; and an output that is electrically connected to a load, and, via a first corresponding choke, to the ring bus; at least one fuel-cell interface converter (FIC) that converts direct current (DC) electrical power to alternating current (AC) electrical power, each FIC of the at least one FIC being electrically connected to the ring bus via a second corresponding choke; and a fuel cell module corresponding to and electrically connected to each FIC, the fuel cell module including a fuel cell.

Abstract: In one aspect, a hybrid circuit protection device for current-limiting a fault current between a source and a load during a fault is provided. The hybrid circuit protection device includes an input configured to couple to the source, an output configured to couple to the load, a return configured to couple the source to the load, a main switch configured to selectively couple the input to the output, a switching network coupled in parallel with the main switch, and a controller. The controller is configured to determine that the main switch has opened in response to the fault current, where the fault current has an initial value, and activate the switching network to current-limit the fault current to less than the initial value during the fault.

Abstract: Disclosed herein is a hybrid resonant capacitor circuit including a first capacitor configured to discharge resonant current to interrupt a load current to a switch in parallel with the hybrid resonant capacitor circuit, a second capacitor coupled in parallel with the first capacitor, wherein the second capacitor is configured to transfer energy stored in the second capacitor to the first capacitor after discharge of the resonant current from the first capacitor, and a current limiter coupled in series with the second capacitor. A static transfer switch including a thyristor switch and the hybrid resonant capacitor circuit is also disclosed herein, as is a method for facilitating multiple consecutive voltage source transfers between a first voltage source and a second voltage source powering a load, using the hybrid resonant capacitor circuit.

Abstract: The present invention is directed to an improved smart green power node using predictive switching, predictive operation at a daily and hourly level, and both grid connected and island operating modes with built-in cybersecurity.

Abstract: In one aspect, a solid-state switching apparatus is provided that includes a pair of anti-parallel thyristors, a quasi-resonant turn-off circuit, a sensor, and a control circuit. The turn-off circuit is coupled in parallel with the pair of anti-parallel thyristors and includes a first selectively conductive path and a second selectively conductive path. The sensor is configured to sense a thyristor current conducted by at least one of the pair of anti-parallel thyristors. The control circuit is configured to receive the sensed thyristor current from the sensor and determine a magnitude of the sensed thyristor current and a polarity of the sensed thyristor current. The control circuit is further configured to activate, in response to determining that the magnitude is greater than a threshold value, one of the first selectively conductive path and the second selectively conductive path based on the polarity to commutate and interrupt the thyristor current.

Abstract: In one aspect, a hybrid circuit protection device for current-limiting a fault current between a source and a load during a fault is provided. The hybrid circuit protection device includes an input configured to couple to the source, an output configured to couple to the load, a return configured to couple the source to the load, a main switch configured to selectively couple the input to the output, a switching network coupled in parallel with the main switch, and a controller. The controller is configured to determine that the main switch has opened in response to the fault current, where the fault current has an initial value, and activate the switching network to current-limit the fault current to less than the initial value during the fault.

Abstract: A method of operating a static transfer switch is provided. The method includes monitoring a voltage waveform for each phase of first and second power sources, and calculating flux for each phase of the power sources. The method also includes determining (i) a first flux difference between the respective flux of the first phases of the first and second power sources, (ii) a second flux difference between the respective flux of the second phases of the first and second power sources, and (iii) a third flux difference between the respective flux of the third phases of the first and second power sources. The method further includes turning off a third solid-state switch to disconnect the third phase of the first power source from a load, in response to the controller determining that the third flux difference is greater the first and second flux differences.

Abstract: In one aspect, a solid-state switching apparatus is provided that includes a pair of anti-parallel thyristors, a quasi-resonant turn-off circuit, a sensor, and a control circuit. The turn-off circuit is coupled in parallel with the pair of anti-parallel thyristors and includes a first selectively conductive path and a second selectively conductive path. The sensor is configured to sense a thyristor current conducted by at least one of the pair of anti-parallel thyristors. The control circuit is configured to receive the sensed thyristor current from the sensor and determine a magnitude of the sensed thyristor current and a polarity of the sensed thyristor current. The control circuit is further configured to activate, in response to determining that the magnitude is greater than a threshold value, one of the first selectively conductive path and the second selectively conductive path based on the polarity to commutate and interrupt the thyristor current.

Abstract: A method of operating a static transfer switch is provided. The method includes monitoring a voltage waveform for each phase of first and second power sources, and calculating flux for each phase of the power sources. The method also includes determining (i) a first flux difference between the respective flux of the first phases of the first and second power sources, (ii) a second flux difference between the respective flux of the second phases of the first and second power sources, and (iii) a third flux difference between the respective flux of the third phases of the first and second power sources. The method further includes turning off a third solid-state switch to disconnect the third phase of the first power source from a load, in response to the controller determining that the third flux difference is greater the first and second flux differences.

Abstract: Disclosed herein is a hybrid resonant capacitor circuit including a first capacitor configured to discharge resonant current to interrupt a load current to a switch in parallel with the hybrid resonant capacitor circuit, a second capacitor coupled in parallel with the first capacitor, wherein the second capacitor is configured to transfer energy stored in the second capacitor to the first capacitor after discharge of the resonant current from the first capacitor, and a current limiter coupled in series with the second capacitor. A static transfer switch including a thyristor switch and the hybrid resonant capacitor circuit is also disclosed herein, as is a method for facilitating multiple consecutive voltage source transfers between a first voltage source and a second voltage source powering a load, using the hybrid resonant capacitor circuit.

Abstract: A system includes: a ring bus; a plurality of static uninterruptible power supplies (UPSs), each static UPS of the plurality of static UPSs including: at least one battery; an input that is electrically connected to a first external electrical power source; and an output that is electrically connected to a load, and, via a first corresponding choke, to the ring bus; at least one fuel-cell interface converter (FIC) that converts direct current (DC) electrical power to alternating current (AC) electrical power, each FIC of the at least one FIC being electrically connected to the ring bus via a second corresponding choke; and a fuel cell module corresponding to and electrically connected to each FIC, the fuel cell module including a fuel cell.

Abstract: In one aspect, a quasi-resonant turn-off circuit is provided. The quasi-resonant turn-off circuit is couplable in parallel with a pair of anti-parallel thyristors. The quasi-resonant turn-off circuit includes a resonant capacitor and an energy recovery circuit. The resonant capacitor is configured to supply a charge to the pair of anti-parallel thyristors to decrease a turn-off time of the pair of anti-parallel thyristors. The energy recovery circuit is configured to recharge the resonant capacitor using remnant energy left in parasitic inductances coupled to the quasi-resonant turn-off circuit after the pair of anti-parallel thyristors is off.

Abstract: A method includes energizing a transformer from a deenergized state by turning on a solid-state transfer switch to conductively couple a power source on a first side of the solid-state transfer switch and a transformer on a second side of the solid-state transfer switch, and evaluating an inrush current to the transformer from the power source. The method includes turning off the solid-state transfer switch to conductively decouple the power source and the transformer in response to the inrush current meeting a first criterion, determining a recoupling timing for the solid-state transfer switch, and turning on the solid-state transfer switch in response to the recoupling timing effective to complete energization of the transformer with the inrush current to the transformer being limited by the first criterion.

Abstract: A method includes energizing a transformer from a deenergized state by turning on a solid-state transfer switch to conductively couple a power source on a first side of the solid-state transfer switch and a transformer on a second side of the solid-state transfer switch, and evaluating an inrush current to the transformer from the power source. The method includes turning off the solid-state transfer switch to conductively decouple the power source and the transformer in response to the inrush current meeting a first criterion, determining a recoupling timing for the solid-state transfer switch, and turning on the solid-state transfer switch in response to the recoupling timing effective to complete energization of the transformer with the inrush current to the transformer being limited by the first criterion.

Abstract: An apparatus and method that can accelerate the turn off time for a thyristor current interrupter. Following commutation of a load current from a main thyristor to an auxiliary turn-off unit, a capacitor of the auxiliary turn-off unit can provide a resonant current to create a zero current crossing for turning the main thyristor off, as well as provide a reverse bias voltage for the main thyristor. The auxiliary turn-off unit can hold the main thyristor off and facilitate sufficient time being available for main thyristor to block forward system voltage. A voltage level of another capacitor of the auxiliary turn-off unit can, with a switch of the auxiliary turn-off unit and the main thyristor turned off, be increased to a level that triggers at least one voltage-clamping unit to absorb electrical power from that capacitor.

Abstract: A static transfer switch is provided for supplying power to a load alternately from two different power sources. Switching between the two power sources may occur within a fraction of one electrical cycle. In response to sensing degraded performance in the power source supplying the load, a gate signal is turned off to a first switch coupled between the power source and the load. A third switch coupled between an energy storage and the first switch is also closed to release a current to the input or output of the first switch The current forces a drop in current conducted through the first switch and causes the first switch to open and stop conducting current. A second switch coupled between the alternate power source and the load is then closed to supply power to the load from the alternate power source.