Abstract: In one aspect, the present subject matter discloses a method for overvoltage protection of an electrical system. The method may generally include detecting an overvoltage condition on an electrical system; and switching on, in response to the detected overvoltage condition, an impedance connected to the electrical system, wherein the impedance clamps voltage on the electrical system.

Abstract: Embodiments of the invention can provide systems, methods, and apparatus for converting direct current (DC) power to alternating current (AC) power. According to one embodiment, a system for converting DC power to AC power can be provided. The system can include a DC power source that provides a first DC power signal to a converter. Coupled to the converter can be a controller for transforming the first DC power signal into a plurality of AC power signals. The controller can also phase shift at least one of the plurality of AC power signals and combine the phase shifted AC power signal with at least one of the other of the plurality of AC power signals to provide a second DC power signal. The controller can also convert the second DC power signal to an AC power signal.

Abstract: Systems and methods for improving low-load efficiency of power converters are provided. The power converter can include one or more bridge circuits having multiple switching modules, such as insulated gate bipolar transistor (IGBT) modules, connected in parallel within the same bridge circuit. The power converter is configured to convert power from an input power source, such as a photovoltaic array or a wind turbine, into output power at a grid frequency. To avoid excessive switching losses at low load conditions, the power converter can be controlled to selectively operate a subset of the switching modules within the same bridge circuit based on a load condition for the power converter. The remaining switching modules in the bridge circuit can be disabled.

Abstract: A power converter system includes a converter configured to be coupled to a power generation unit for receiving power from the power generation unit, and a bus coupled to the converter, wherein a voltage is generated across the bus when electricity is conducted through the power converter system. The power converter system also includes an inverter coupled to the bus and configured to supply power to an electrical distribution network, and a control system coupled to the converter and to the inverter. The control system is configured to gradually adjust the voltage across the bus during at least one of a shutdown sequence and a startup sequence of the power converter system.

Abstract: A method and system for reducing a disturbance of an electric grid signal in a wind turbine is provided. The method includes providing a generator for the wind turbine system, and, coupling a power converter to the generator, the power converter. The power converter is configured to monitor at least one of a negative sequence component and a positive sequence component of a signal transmitted from an electric grid, determine if a disturbance exists based on the monitored signal, determine at least a portion of a magnitude of the negative sequence component of the signal, and, orient a voltage of the signal based on the determined magnitude negative sequence component to modify the instantaneous power flow through the power converter.

Abstract: A device includes a first thyristor element configured to be coupled to a first voltage line and a second voltage line, wherein the first voltage line is configured to transmit power in a first phase and the second voltage line is configured to transmit power in a second phase. The device includes a second thyristor element configured to be coupled to the second voltage line and a third voltage line, wherein the third voltage line is configured to transmit power in a third phase. The device includes a third thyristor element configured to be coupled to the first voltage line and the third voltage line.

Abstract: A power conversion system for providing power to an electrical grid is described. The power conversion system includes a power converter coupled to a power source and the electrical grid. The power conversion system also includes a converter controller coupled to the power converter and configured to control operation of the power converter to actively cancel harmonic current received at the power converter from the electrical grid.

Abstract: A power conversion system for providing power to an electrical grid is described. The system includes a power converter coupled to a direct current (DC) power source. The system also includes a contactor coupled to the power converter and the electrical grid and configured to selectively electrically couple the power converter to the electrical grid. The system also includes a system controller communicatively coupled to the power converter and the contactor and configured to close the contactor to electrically couple the power converter to the electrical grid and to activate the power converter when a DC voltage provided has remained higher than a voltage level for a length of time. The system controller is also configured to deactivate the power converter, while the contactor is maintained in the closed position, when an alternating current (AC) power output has remained lower than a power level for a length of time.

Abstract: An electric power converter for a renewable power source includes at least one alternating current (AC) conduit coupled to an external AC power device and at least one direct current (DC) conduit coupled to an external DC power device. The converter also includes at least one immersion structure defining at least one immersion cavity therein and a plurality of semiconductor devices. The semiconductor devices include a substrate positioned within the immersion cavity. The substrate defines a plurality of heat transfer surfaces thereon. The semiconductor devices also include at least one semiconductor die coupled to the substrate, the AC conduit, and the DC conduit. The converter further includes a liquid at least partially filling the immersion cavity such that the semiconductor die is fully immersed in and in direct contact with the liquid. Heat generated in the semiconductor device induces a phase change in the liquid.

Abstract: A power converter system includes a converter, a DC link, an inverter, a damping circuit, and a control system. The converter includes an input to couple to a power generation unit and an output to provide a direct current (DC) DC power output. The DC link includes a capacitor coupled to the converter output. A voltage across the capacitor defines a DC link voltage. The inverter includes an input coupled to the DC link. The damping circuit is coupled between the converter and the inverter in parallel with the DC link capacitor. The damping circuit includes a normally closed switching device, and a resistor coupled in series with the normally closed switching device. The control system is coupled to the damping circuit and configured to control the normally closed switching device as a function of at least one operating parameter of the power converter system.

Abstract: Systems, methods, and apparatus for providing a dynamic break and distortion filter. In one embodiment, an apparatus can include an inverter providing alternating current (AC) power at one of a first and second chopping frequency and a filter. The filter can include an input port receiving the AC power and an output port providing output power by selectively passing the AC power from the input port to the output port. The filter may further include an inductor electrically connected to one of the input port and output port and a capacitor electrically connected to the inductor and to a resistor, wherein current does not substantially flow through the inductor and capacitor at the first chopping frequency and does substantially flow through the inductor and capacitor at the second chopping frequency, and wherein the AC power with the second chopping frequency is dissipated in the resistor.

Abstract: A boost converter including two or more inductors coupled to an input DC power source and to switches that can each be modulated with a modulation signal to control the output power of the boost converter. Two or more of the modulation signals have a relative phase other than 360° divided by the number of switches.

Abstract: A power conversion system for providing power to an electrical grid is described. The power conversion system includes a power converter coupled to a photovoltaic (PV) array and configured to control a PV array voltage. The power conversion system also includes a system controller communicatively coupled to the power converter and configured to select from a first reduced power operating point and a second reduced power operating point when a power available from the PV array is greater than a rated output power of the power conversion system.

Abstract: An electrical power generating system including a power generating device, a power converter connected to the power generating device, and an electrical controller connected to the power converter. The electrical controller is configured to limit a peak junction temperature of the power converter by applying at least one junction temperature derating function.

Abstract: An apparatus and method for improved current shunt sensing in an electrical system, such as a renewable energy electrical system, is disclosed. A current shunt according to aspects of the present disclosure includes a conductive portion that is placed in series with an electrical system The current shunt includes a sensing element that is used to measure the voltage across the conductive portion of the current shunt. The sensing element has an increased width relative to the width of the conductive portion of the shunt. The increased width of the sensing element provides for improved current shunt sensing that results in more accurate voltage (and thus current) measurements across a wide range of frequencies.

Abstract: A photovoltaic power system includes one or more photovoltaic cells that supplies an output power, a controller that controls an angle of the one or more photovoltaic cells with respect to an incident light, and a power converter that converts the output power of the photovoltaic cells to converted output power, wherein the power converter has a threshold input power. The controller is configured to control the angle of the one or more photovoltaic cells with respect to the incident light such that a total output power of the photovoltaic cells is at or below the threshold input power of the power converter.

Abstract: Embodiments of the invention can provide systems, methods, and an apparatus for converting direct current (DC) power to alternating current (AC) power. According to one embodiment, a system for converting DC power to AC power can be provided. The system can include a DC power source electrically coupled to a DC-to-DC converter. The DC power source can be associated with a first ground, and the DC-to-DC converter can be operable to isolate the power provided by the DC power source from the first ground. The DC-to-DC converter can be further operable to condition the DC power and to provide the conditioned DC power to an inverter. The inverter can receive the conditioned DC power and can convert the conditioned DC power to AC power. The AC power can be associated with a second ground and can be provided to at least one load electrically coupled to the inverter.

Abstract: A switching circuit for use in a power converter is provided. The switching circuit includes an insulated gate bipolar transistor (IGBT) including a gate terminal, a collector terminal, and an emitter terminal, a gate drive circuit electrically coupled to the gate terminal and configured to switch the IGBT on and off, and, a temperature drift resistant clamp circuit electrically coupled between the gate terminal and the collector terminal of the IGBT, the temperature drift resistant clamp circuit configured to maintain a voltage at the collector terminal below a threshold voltage and facilitate reducing the effects of temperature on operation of the switching circuit.

Abstract: A power conversion system for providing power to an electrical grid is described. The system includes a boost converter coupled to a photovoltaic (PV) array and configured to control a PV array voltage. The system also includes an inverter coupled to the boost converter by at least one conductor and configured to regulate a voltage drop across the at least one conductor. The system also includes a system controller configured to control operation of the boost converter and the inverter.

Abstract: Embodiments of the invention can provide systems, methods, and apparatus for operating a power converter. According to one embodiment, a system for operating a power converter can be provided. The system can include a direct current (DC) power source with an output electrically coupled to an input of the power converter. The system can also include a controller operable to modify the performance of the DC power source through the power converter. As part of this modification, the controller can determine whether a low voltage ride (LVRT) event exists in a load and can adjust the DC power source when a LVRT event occurs.