6025results about "Ac-ac conversion" patented technology

A grid-connected power system includes a primary power source, a back-up power source, a DC/AC inverter and a DC/DC converter. Direct current from the primary power source is supplied to the DC/AC inverter to obtain an alternating current output supplied to a utility grid when power from the utility grid is available to power a load. The output of the inverter is supplied to a selected portion of the load when power from the utility grid is unavailable to the load. Direct current from the back-up power source is supplied to the inverter through a DC/DC converter when power from the utility grid is unavailable to the load. The DC/DC converter converts the voltage of direct current from the back-up power source to direct current having a voltage compatible with the voltage of the primary power source and the inverter. The back-up power source may be charged by the primary power source or by the utility grid. Methods of providing back-up power include converting the voltage of direct current from a back-up power source to direct current of converted voltage and supplying the direct current of converted voltage to a DC/AC inverter.

A soft-switched single-phase quasi-single-stage (QSS) bi-directional inverter/charger converts AC-DC or DC-AC. The inverter/charger comprises a push-pull inverter/rectifier on the dc-side, an isolation transformer which provides ohmic isolation and voltage scaling, two full-bridges on the ac side in cascade, a voltage clamp branch comprising a capacitive energy storage element in series with an active switch with its anti-parallel diode, a passive filter at the ac side to smooth out the high frequency switching voltage ripple at the output, and a corresponding PWM scheme to seamlessly control the converter to operate in all four quadrant operation modes in the output voltage and output current plane, and is capable of converting power in both directions.

A galvanic isolated DC-DC and DC-AC power conversion system is coupled to a plurality of DC sources which are derived from a combination of a plurality of single-phase and three-phase AC-DC converters. The DC-DC and DC-AC power conversion system in one embodiment is configured to provide mixed type outputs (mixed frequency, e.g. DC with 50 or 60 Hz, with 400 Hz; mixed voltage levels).

A load control device for controlling the amount of power delivered from an AC power source to an electrical load is operable to conduct enough current through a thyristor of a connected dimmer switch to exceed rated latching and holding currents of the thyristor. The load control device comprises a controllable-load circuit operable to conduct a controllable-load current through the thyristor of the dimmer switch. The load control device disables the controllable-load circuit when the phase-control voltage received from the dimmer switch is a reverse phase-control waveform. When the phase-control voltage received from the dimmer switch is a forward phase-control waveform, the load control device is operable to decrease the magnitude of the controllable-load current so as to conduct only enough current as is required in order to exceed rated latching and holding currents of the thyristor.

A power converter system for supplying an output voltage is provided. The power converter system is adapted to operate in a normal mode and a fault mode. The system comprises a plurality of bridges and a plurality of transformers. The system further comprises a plurality of dc link capacitors, each coupled across a corresponding bridge. The system also includes a controller adapted for, during the normal mode, switching each bridge with a respective normal phase shift. During the fault mode, the controller is adapted for switching each of the remaining ones of the bridges with a respective adjusted phase shift to generate the output voltage. During the fault mode, at least one of the plurality of bridges is bypassed.

Apparatus and methods for regulating delivery of electrical energy to a lighting load are disclosed. An electrical waveform is received from a source of electrical energy. An integration value is generated based on a square of an amplitude of the received waveform. Electrical energy is delivered to the load until the integration value exceeds a threshold value. Thereafter, the delivery of electrical energy to the load is discontinued.

A variable speed wind turbine is disclosed comprising a turbine rotor that drives a doubly-fed induction generator, a matrix converter which converts variable frequency output into constant frequency output, and a control unit and a protection circuit for the matrix converter. Power is circulated in the system allowing for sensorless detection of rotor position and better output ratios of power from the system.

A two-wire smart load control device, such as an electronic switch, for controlling the power delivered from a power source to an electrical load comprises a relay for conducting a load current through the load and an in-line power supply coupled in series with the relay for generating a supply voltage across a capacitor when the relay is conductive. The power supply controls when the capacitor charges asynchronously with respect to the frequency of the source. The capacitor conducts the load current for at least a portion of a line cycle of the source when the relay is conductive. The load control device also comprises a bidirectional semiconductor switch, which is controlled to minimize the inrush current conducted through the relay. The bidirectional semiconductor switch is rendered conductive in response to an over-current condition in the capacitor of the power supply, and the relay is rendered non-conductive in response to an over-temperature condition in the power supply.

The invention in the simplest form is an improved variable speed engine/generator set with an integrated power conditioning system and control method, used to generate high quality AC power with optimum fuel efficiency and reduced emissions. The variable speed generator control scheme allows for load adaptive speed control of engine and generator field. The transformerless power inverter topology and control method provides the necessary output frequency, voltage and/or current waveform regulation, harmonic distortion rejection, and provides for single phase, or unbalanced loading.

The invention is directed to controlling an electric motor by means of a frequency converter. The frequency converter can be connected to one of several different mains voltages. According to the present invention, the maximum output power of the frequency converter, is limited when the actual mains voltage is lower than the maximum nominal mains voltage, for which the frequency converter is designed, and during the limitation the frequency converter controls the speed of the motor within a power range up to a limited maximum output power. This gives a genuine multi-voltage unit, which can be connected to a wide range of mains voltages.

The use of low permeability magnetic material (NSME) with the disclosed design strategies form a two-stage isolated output converter system with the distinct advantages of superior density, efficiency, thermal operating bandwidth, service life, transient survival, and form factor flexibility over the prior art. These improvements are realized by, optimized application of NSME, efficient rectifying flyback management techniques, inclusion of switching buffers that substantially reduce switching losses. The instant invention provides power factor correction, output regulation, inrush limiting, over voltage, over current, over temperature, and transient protection, multi-converter load sharing, hot swapability, and fault signals.

The disclosed system is designed, specified, and certified to function from −40 deg. C. to +65 deg. C. from a 180 vac to 264 vac 50/60 Hz input line and supports 1000 watts of output or 600 watts from 90 vac to 120 vac 50/60 Hz line input at greater then 0.95 power factor and features a packaged power density of 14 watts per cu. in. at high line.

A sub-sea power delivery system includes a plurality of modular power converter building blocks on each of the power source side and the sub-sea load side that are stacked and interconnected to meet site expansion requirements and electrical load topologies. The power delivery system comprises a system DC transmission link/bus, wherein the system DC link is configured to carry HVDC or MVDC power from an onshore utility or topside power source to multiple sub-sea load modules. The stacked modular power converter topology on the sub-sea side of the sub-sea power delivery system is symmetrical with the stacked modular power converter topology on the on-shore/top-side of the sub-sea power delivery system.

A power system for providing an output power to a load is provided. The system comprises a generator configured to generate an alternating current input power and an power converter system coupled to the generator and configured to generate an output power and provide the output power to the load through at least one transformer. The system further comprises a converter control system coupled to the converter system and configured to drive the converter system in an interleaved pattern to reduce harmonic components in the output power and the alternating current input power.

A wind powered turbine with low voltage ride-through capability. An inverter is connected to the output of a turbine generator. The generator output is conditioned by the inverter resulting in an output voltage and current at a frequency and phase angle appropriate for transmission to a three-phase utility grid. A frequency and phase angle sensor is connected to the utility grid operative during a fault on the grid. A control system is connected to the sensor and to the inverter. The control system output is a current command signal enabling the inverter to put out a current waveform, which is of the same phase and frequency as detected by the sensor. The control system synthesizes current waveform templates for all three-phases based on a sensed voltage on one phase and transmits currents to all three-phases of the electrical system based on the synthesized current waveforms.

An electric drive apparatus and method for controlling medium-voltage alternating current motors wherein a multi-phase power transformer having multiple secondary windings provides multi-phase power to multiple power cells which provide four quadrant operation. Each power cell has a single-phase output and is controllable by a modulation controller. The power cells are connected in series thus permitting the maximum output voltage for each cell to be less than the maximum line-to-line voltage. Each power cell can have a rectifier portion to convert input AC-to-DC, capacitors, an output DC-to-AC inverter, a regenerative bridge converter connected in parallel with the rectifier portion and a local modulation controller connected to a master controller.

An inductive power transfer system (10) for roadways includes at least one drive unit arrangement (50) coupled to at least one drive coil arrangement (40) disposed along a roadway (20) for generating a magnetic field extending upwardly from the roadway (20), and at least one vehicle (30) including a corresponding pickup coil arrangement (60) coupled to a power conditioning circuit arrangement (80, 200) for receiving the extending magnetic field for providing power to operate the at least one vehicle (30). The at least one drive unit arrangement (50) is operable to excite, for example at resonance, the at least one drive coil arrangement (40) at a fundamental frequency (f₀) of at least 30 kHz, preferably at least 50 kHz, more preferably at least 100 kHz, and most preferably at least 140 kHz. The at least one drive coil arrangement (40) is implemented to be substantially devoid of ferromagnetic components for providing a path for the extending magnetic field. Optionally, the at least one drive unit arrangement (50) is operable to employ a balanced class-E amplifier arrangement for exciting the at least one drive coil arrangement (40) at the fundamental frequency (f₀). Optionally, the at least one drive unit arrangement (50) is operable to employ one or more Silicon Carbide semiconductor devices for switching the currents provided to the corresponding at least one drive coil arrangement (40). Optionally, there is further included a passive and/or active suppression arrangement (100, 110, 120, 130, 140) for suppressing harmonic magnetic field components generated by the system (10) at multiples of the fundamental frequency (f₀) when in operation.

An AC/DC/AC power converter is constructed without using any electrolytic capacitor, such that it is more compact, durable and reliable. This converter only required a small capacitance for its DC link and this capacitor can be easily obtainable with other types of capacitors such as film or ceramic type. The system further includes means to disconnect both input and output to this DC bus capacitor. A controller capable of fast monitoring the DC bus voltage is also able of quickly disconnecting the capacitor out of either input or output energy path to prevent the capacitor from being charged to over-voltage. The controller also possesses capability of re-connecting the disrupted energy path once the DC bus voltage returns to normal.

Disclosed herein is a capacitor mounting type inverter unit having a cooling block, an inverter including a plurality of phases of switching circuits provided on the cooling block, and a smoothing capacitor. The inverter unit includes a cover having a first recess for accommodating the inverter and a second recess for accommodating the smoothing capacitor. The second recess has a depth larger than that of the first recess. The second recess is filled with resin in the condition where the smoothing capacitor is accommodated in the second recess.