111results about "Dc circuit with intermediate ac" patented technology

A power pick-up for an Inductively Coupled Power Transfer (ICPT) system is provided having a resonant pick up circuit. The natural frequency of the pick-up circuit may be varied by controlling the conductance or capacitance of a variable reactive in the resonant circuit. The load being supplied by the pick-up circuit is sensed, and the effective capacitance or inductance of the variable reactive component is controlled to vary the natural resonant frequency of the pick-up circuit to thereby control the power flow into the pick-up to satisfy the power required by the load.

A resonant converter is provided which may be used for supplying power to the primary conductive path of an inductively coupled power transfer (ICPT) system. The converter includes a variable reactive element in the resonant circuit which may be controlled to vary the effective inductance or capacitance of the reactive element. The frequency of the converter is stabilised to a nominal value by sensing the frequency of the converter resonant circuit, comparing the sensed frequency with a nominal frequency and varying the effective inductance or capacitance of the variable reactive element to adjust the converter frequency toward the nominal frequency.

Apparatus are disclosed for controlling the delivery of power to DC components such as computer components, microprocessors or the like. Designs of rectifier circuitry are presented which are appropriate for faster components, lower voltages, and higher currents. Embodiments are especially suited to applications which cause rapid changes in the conductance of the load, even in the sub-microsecond time domain as is common in computer applications and the like and in powering electronics equipment, especially a distributed system and especially a system wherein low voltage at high current is required. Embodiments and sub elements provide energy storage for low voltage, high current electronic loads, an ability to supply current with rapid time variation, providing extremely low inductance connections, permitting components to be located relatively remotely from the powered electronic load.

Disclosed is an LED drive circuit with a thyristor dimmer and a control method, by combining the discharge current of the thyristor dimmer in the conduction stage of each AC cycle and the current after conduction until the LED load is lit The discharge current during the period is divided. When the thyristor dimmer starts to conduct, the discharge circuit is controlled to discharge with a larger first current, and after the conduction, the discharge circuit is controlled to discharge with a smaller second current. The discharge can reduce the average discharge current in each cycle of the discharge circuit, reduce the discharge loss, and improve the efficiency of the LED drive circuit.

Method and apparatus are disclosed for providing a constant voltage, high frequency sinusoidal output across a varying load, using either a single or multiple switch topology operating at constant frequency while maintaining high efficiency over the entire load range. This embodiment is especially suited to applications which require the sinusoidal voltage be held very close to a desired value in the presence of rapid changes in the conductance of the load, even in the sub-microsecond time domain as is common in computer applications and the like and in powering electronics equipment, especially a distributed system and especially a system wherein low voltage at high current is required. Embodiments and sub elements provide energy storage for low voltage, high current electronic loads, an ability to supply current with rapid time variation, connection of the energy storage element to the electronic load through specially configured conductors designed to minimize the created magnetic field around said conductors, providing extremely low inductance connections, permitting larger energy storage elements to be utilized, permitting energy storage to be located relatively remotely from the powered electronic load, and a steady voltage from a transformer isolated, high frequency ac to dc converter under varying load without the necessity for feedback control, among other aspects. The addition of capacitors which interact with the leakage inductance of the transformer to produce a natural regulation condition is used and the relationship between the value of the leakage inductance of the transformer and that of the added capacitances is different from the condition of resonance at the operating frequency.

A switching type power converter circuit includes a step-down converter circuit, a DC / AC converter circuit coupled to the step-down converter circuit, and a rectifier circuit coupled to the DC / AC converter circuit. In one embodiment, the DC / AC converter operates with near 50% duty cycle and with substantially zero-voltage, substantially minimum current switching in a resonant mode. An auxiliary step down converter may be added. An AC / DC converter front end with a full-wave bridge, an RF filter, and a power factor correction circuit may also be added.

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 switching power supply transmits power between a single front end including electromagnetic interference filtering and power factor correction circuits to an output end at a high voltage and high frequency from which any desired DC voltage or waveform may be readily and directly derived with high efficiency in order to reduce size and weight of components including transformers at the output end and allow greater variety of connection wiring of reduced weight and volume to be used. The high frequency is limited at the low frequency end by the frequency at which significant power can be transferred through, for example, a ferrite core or other transformer of sufficiently low volume to accommodate closely spaced loads or power converters and at the high frequency end by the wavelength in the connection wiring such that 1 / 10 wavelength is greater than one thousand feet. Branches of the power distribution system which are not desired to be in use can be operated at zero power and be brought back on line within milliseconds, when needed. Power distribution among respective branches of the power distribution system can be controlled by varying the high frequency of power transmission and appropriate filtering.

An auxiliary power supply equipment for a high voltage installation includes a power source at ground potential, a load circuit at high potential, and a transmission link for coupling the power source to the load circuit. The power source includes a high frequency voltage generator, and the transmission link comprises a first and a second current path. Each path is closed by capacitive coupling to provide insulation between the ground potential and the high potential, and each current path has a reactive compensation means for series compensation of reactive power generated by the capacitive coupling.