119results about "Constant-current supply ac circuits" patented technology

The supercapacitor-based grid fault ride-through system provides a dynamic model of a wind generation system including a Voltage Source Converter (VSC), which functions as a Static Compensator (STATCOM). The power control capability of the STATCOM is extended by incorporating energy stored in a supercapacitor. The system implements a vector control technique based on the decoupling of real and reactive power. Simulation results show that a fixed speed induction generator is capable of withstanding a significant grid fault when aided by the supercapacitor-based grid fault ride-through system. Moreover, the induction generator regains its pre-fault status immediately after the fault is cleared.

A lighting system having a power supply and at least one luminaire. The power supply includes a power supply input to receive a first signal having a first frequency and a circuit for converting the first signal to a second signal. The power supply also includes at least one power supply output to output a second signal having a substantially constant current and a second frequency distinctly higher than the first frequency. The luminaire includes a lamp coupled to a lamp driver circuit, which has an input for receiving the output signal from the power supply and which is configured to use the received output signal to operate the lamp. The lamp driver input and the power supply output may be connected by a flexible cable.

A system and method for providing direct-current power is described. In one embodiment a direct current voltage is converted into at least two regulated DC voltages, and a first of the at least two regulated DC voltages is applied across a first and second outputs and a second of the at least two regulated DC voltages is applied across the second output and a third output. And when a first impedance across the first and second outputs is less than a second impedance across the second and third outputs, current is received via the second output while delivering power to the first and second impedances.

A lamp base having an electrical device recharging receptacle configured to receive a plug from a recharging device for a portable rechargeable electronic device. The receptacle is configured as a standard automobile cigarette lighter receptacle. The receptacle includes standard cigarette lighter receptacle electrical contacts that are connected to a voltage and current conversion circuit for receiving standard household voltage and converting it into standard automotive voltage and current. An adapter receptacle is provided in the lamp base with securable replacement electrical and mechanical connection mechanism, wherein the conversion circuit provides a voltage and current to the adapter receptacle. A replaceably securable USB adapter plug comprising a second conversion circuit for converting the voltage and current provided to the adapter receptacle into a standard USB voltage and current. The replaceably securable USB adapter plug may be electrically and mechanically disconnected and replaced with an upgraded replaceably securable USB adapter plug having a third conversion circuit to convert the voltage and current provided to a different USB voltage and current.

The invention discloses an uninterruptible power supply circuit, which comprises a bidirectional selection switch, a first-class bidirectional converter, a second-class bidirectional converter, an energy storage device and a filtering device, wherein the bidirectional selection switch is alternatively connected with an alternating-current power supply and the energy storage device; the first-class bidirectional converter is arranged between the bidirectional selection switch and the filtering device; the second-class bidirectional converter is arranged between the filtering device and a load; and both the first-class bidirectional converter and the second-class bidirectional converter have rectifying or inverting functions. Due to the adoption of the bidirectional converters and the bidirectional selection switch, alternating-current mains supply, the energy storage device and a charger needed by the energy storage device can share the bidirectional converters. Compared with the conventional uninterruptible power supply circuit, the uninterruptible power supply circuit disclosed by the invention has the advantage that an additional charger or a high-power inverter is not needed, so that the circuit structure of the uninterruptible power supply circuit is simplified.

A superposition principle of waveform based on conceptions of waveform continuity and flexible regulation of voltage proposes three concepts, respectively being flexible AC transformation, flexible power transmission and transformation and flexible voltage regulation; proposes three new technologies, respectively being a transient impedance technology, a flexible stepless voltage regulation technology and a flexible stepped voltage regulation technology; proposes three new products, being an AC voltage regulating electronic switch, a transient impedance transformer and a high-speed voltage regulating transformer; proposes six high-voltage power grid connection methods, being a power grid connection method type of a transient impedance transformer, a power grid connection method of a transient impedance step up auto transformer and the like; and proposes a new reactive compensation connection method for a reactive compensation device.

Unique systems, methods, techniques and apparatuses of a power grid control system. One exemplary embodiment is a nested microgrid system comprising a first microgrid including a network controller, a second microgrid, a third microgrid, a first restoration path selectively coupled between the second portion of the first microgrid and the second microgrid, and a second restoration path selectively coupled between the second portion of the first microgrid and the third microgrid. The network controller is configured isolate the first portion of the first microgrid from the second portion of the first microgrid, calculate weighting factors for the first and second restoration paths, select the first restoration path using the first weighting factor and the second weighting factor, and couple the second portion of the first microgrid to the second microgrid using the first restoration path.

A power supply having an input, wherein the power supply includes a multi-winding transformer having an input and a plurality of outputs, and a plurality of rectifiers to provide a plurality of DC output voltages, wherein each rectifier is coupled to an output of the multi-winding transformer. The power supply further includes a regulator circuit coupled between the transformer input and one of the transformer outputs, and configured to regulate an input voltage to the multi-winding transformer to minimize a variance of each rectifier DC output voltage.

Techniques for DC-to-AC conversion are disclosed, and may be embodied in a solar inverter device that can operatively couple to a power grid. The device includes a photovoltaic (PV) stack including series-connected PV modules. Each PV module is associated with a capacitor for storing output of that PV module. A positive terminator circuit switches a negative end of the PV stack to ground during positive half of grid cycle, and a negative terminator switches a positive end of the PV stack to ground during negative half of grid cycle. A connecting branch couples each PV module output to a common bus, each branch including control circuitry configured to selectively couple the corresponding PV module output to bus. During a first half of grid cycle, some of the capacitors discharge to the grid while a balance of the capacitors charge in preparation for discharge during a second half of grid cycle.

A direct current power system according to one non-limiting embodiment includes a direct current power source operable to distribute a direct current voltage throughout at least one structure, and at least one controller operable to selectively couple a direct current load to the direct current voltage in response to a wireless signal from an energy-harvesting switch.

A method of power point tracking for operating a photovoltaic power plant, which includes a DC-DC converter of the output voltage of a panel having a power switch driven by a PWM control signal of variable duty-cycle generated by a PWM control circuit, in discontinuous conduction mode or continuous conduction mode depending on the current load of the converter, is implemented by low cost analog circuits. The method does not require the use of any analog-to-digital conversion, digital processing or storage resources and may use a single voltage sensor.

The invention elaborates on the waveform addition principle based on waveform continuity and harmonic wave viewpoint, discloses three concepts of flexible alternating current transformation, flexible power transmission and transformation and flexible voltage regulation, discloses three new technologies of the transient impedance technology, the flexible stipples voltage regulating technology and the flexible stepped voltage regulating technology, and discloses three new products of an alternating current voltage regulating electronic switch, a transient impedance transformer and a high speed voltage regulating transformer, and discloses six high-voltage power grid connection methods of a high-voltage power grid connection method for the transient impedance transformer type, a high-voltage power grid connection method for the transient impedance boosting self-coupling transformer type and the like. The novel reactive compensation connection method is provided, so that a reactive compensation device can be in series connection and parallel connection at the port of a secondary outgoing wire of a main transformer of a series voltage regulating transformer. The transient impedance transformer based the alternating current voltage regulating electronic switch can be applied to high voltage, super high voltage alternating and direct current power transmission and other systems needing to be safely, efficiently and synchronously controlled and systems needing large capacity stepless voltage regulation.

The converter uses the energy stored in the output filter of a step-down (or buck) converter and in the inductor of a step up / down (or buck-boost) converter to supply a second output of opposite sign. In particular, the converter has a first input receiving an input voltage; a first output supplying a first output voltage of a first sign; a second output supplying a second output voltage of opposite sign; a controlled switch connected between the first input and a first intermediate node; an inductor connected between the first intermediate node and the first output; a diode connected between the first intermediate node and a second intermediate node; and a dual voltage generating circuit connected between the second intermediate node and the second output.

A lamp base having an electrical device recharging receptacle configured to receive a plug from a recharging device for a portable rechargeable electronic device. The receptacle is configured as a standard automobile cigarette lighter receptacle. The receptacle includes standard cigarette lighter receptacle electrical contacts that are connected to a voltage and current conversion circuit for receiving standard household voltage and converting it into standard automotive voltage and current.

Compensation system adapted for use with a battery-powered, PWM-driven portable electronic device to enable consistent power to the device load despite battery voltage drop resulting from battery depletion, comprising: a voltage divider circuit for proportionally adjusting the voltage to a measurable range; an analog-to-digital converter for receiving the output from the voltage divider and converting it into a digital voltage value; and a microprocessing unit for running software code steps for receiving digital voltage input and user-determined power setting input for determining a compensating duty cycle for application by the software to the PWM to drive the load consistently at the user-determined power setting despite decrease in battery voltage resulting from battery depletion.

A rack system is provided that includes a plurality of trays configured to hold a respective plurality of battery-powered UAVs, and a frame configured to support the plurality of trays in a vertical arrangement. Each tray of the plurality of trays includes a platform, bumper and first plurality of electrical contacts. The platform may be configured to carry a UAV of the plurality of battery-powered UAVs. The bumper may be sized and positioned on the platform to guide the UAV to a resting position on the platform. And the first plurality of electrical contacts may be connected to a battery-charging apparatus, and configured to physically and electrically contact a respective second plurality of electrical contacts connected to a respective plurality of batteries on the UAV at the resting position on the platform. A related battery-charging apparatus including a charge switching system for charging battery-powered UAVs is also provided.

Active droop current sharing among power supply units may regulate output currents of power supply units supplying shared current to a common load. The regulation may employ a combination of droop control and active current control. The shared current may be regulated such that each power supply unit provides a substantially equal share of the total current supplied. A current difference between two power supplies may be regulated to be within a desired maximum threshold for current difference.

Procedures to prevent the disconnection of a park of electricity generators from a network in the event of a voltage sag, through which, upon detection of the sag, the voltage travelling to the network is controlled in proportion to the magnitude of the sag; the active power produced by the park, rather than sent to the network, is thus diverted into to storage and / or energy dissipation equipment, keeping the park voltage at a nominal level.The invention also includes a device for carrying out procedures integrating a bypass, transformer, static inverter, static converter, capacitance and dissipation resistance unit, voltage sag detection circuit and control circuit.

A lighting system having a power supply and at least one luminaire. The power supply includes a power supply input to receive a first signal having a first frequency and a circuit for converting the first signal to a second signal. The power supply also includes at least one power supply output to output a second signal having a substantially constant current and a second frequency distinctly higher than the first frequency. The luminaire includes a lamp coupled to a lamp driver circuit, which has an input for receiving the output signal from the power supply and which is configured to use the received output signal to operate the lamp. The lamp driver input and the power supply output may be connected by a flexible cable.

A control methodology for an engine-driven electric machine of a hybrid vehicle electrical system for enabling continued operation of the vehicle electrical system under failure mode conditions that require or result in disconnection of the battery pack from the electrical system. At the onset of a fault condition requiring battery disconnection, the electric machine is controlled to drive the battery pack current toward zero before disconnecting the battery pack. Once the battery pack is disconnected, whether by relay or fuse, the electric machine is controlled to maintain the bus voltage of the electrical system at a specified value. In both operating modes, the electric machine is controlled based on a synchronous vector current command that is determined directly as a function of the control objective (zero battery pack current or maintaining bus voltage) for improved response time compared to a traditional torque-based control.

A flexible cable is provided for a lighting system having a power supply that includes a power supply input to receive a first signal having a first frequency and a circuit for converting the first signal to a second signal, and at least one luminaire coupled to a lamp driver. The cable comprises a first leg of wires for carrying the second signal. The first wire electrically connects a loop output of the power supply to an input of the lamp driver and a second wire electrically connects an output of the lamp driver to a loop return of the power supply. The cable further comprises a second leg of wires electrically connected to a ground of the power supply and the ground of the lamp driver. The second signal has a substantially constant current and a second frequency distinctly higher than the first frequency. The flexible cable further comprises a modular connector.

A power supply and associated method include a power supply converter having a power output and configured to provide a supply voltage through the power output to a communications device. A simplified boost circuit is connected to the power supply converter in parallel but isolated from the power supply converter's bulk input capacitance during normal operation. The boost circuit includes at least one power storage circuit and a charging circuit connected thereto and configured to charge and maintain the power storage circuit to a predetermined voltage and switch the power storage circuit into the power supply converter during an undervoltage condition to transfer the stored power from the power storage circuit to the power supply converter and maintain the supply voltage to the communications device connected thereto for a required hold-up time.