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10577results about "Ac-dc conversion" patented technology

X ray high frequency high voltage generator for medical use diagnose

The invention discloses a medical diagnosis X-ray high frequency high pressure generator, comprising a power supply, a central control unit, a high frequency inverter circuit, a pulse width modulation driving circuit and a high pressure transform and high pressure output circuit. The generator transforms the industrial power to two ways of high frequency and high pressure, a positive direct current high pressure and a negative direct current high pressure are obtained through rectifying and wave-filtering to provide an X-ray ball tube to work. As the frequency is high, the ripple of the rectified and wave-filtered high electric pressure is tiny, and the X-ray quality projected by the X-ray ball tube is high, and the clearance of photos of the perspective and photograph is also high. The X-ray ball tube of a photograph bed or the X-ray ball tube of an electric perspective bed can work if allocated with the high pressure power. The invention is convenient for the medical staff to use the X-ray to do the work of diagnosing diseases. As the high pressure power supply, the invention is also suitable in the safety inspection fields such as industrial flaw detection, civil aviation, station and customs etc, and provides a stable and high qualified high pressure power supply for the equipments.

Control system and method for a universal power conditioning system

A new current loop control system method is proposed for a single-phase grid-tie power conditioning system that can be used under a standalone or a grid-tie mode. This type of inverter utilizes an inductor-capacitor-inductor (LCL) filter as the interface in between inverter and the utility grid. The first set of inductor-capacitor (LC) can be used in the standalone mode, and the complete LCL can be used for the grid-tie mode. A new admittance compensation technique is proposed for the controller design to avoid low stability margin while maintaining sufficient gain at the fundamental frequency. The proposed current loop controller system and admittance compensation technique have been simulated and tested. Simulation results indicate that without the admittance path compensation, the current loop controller output duty cycle is largely offset by an undesired admittance path. At the initial simulation cycle, the power flow may be erratically fed back to the inverter causing catastrophic failure. With admittance path compensation, the output power shows a steady-state offset that matches the design value. Experimental results show that the inverter is capable of both a standalone and a grid-tie connection mode using the LCL filter configuration.

Photovoltaic power plant with distributed DC-to-DC power converters

A solar photovoltaic plant is disclosed where a number of distributed DC-to-DC converters are used in conjunction with a central DC-to-AC converter. Each DC-to-DC converter is dedicated to a portion of the photovoltaic array and tracks the maximum power point voltage thereof. The DC-to-DC converters also boost the photovoltaic voltage and regulate a DC output current for transmission to the central DC-to-AC converter. Five distinct advantages are had over the prior art. First, efficiencies in intra-field power collection are greatly improved by transferring power at higher DC voltages. Second, the number of independent photovoltaic maximum power point trackers in the power plant can be increased, in a cost effective manner, to optimize the overall photovoltaic array energy harvest. Third, each DC-to-DC converter output “looks” like a current source at the input of the DC-to-AC converter and therefore can be easily paralleled. Fourth, the current source nature of the DC-to-DC converter outputs enables the DC-to-AC converter to operate with a minimum, fixed DC bus voltage to provide maximum DC-to-AC power conversion efficiencies. And fifth, each distributed DC-to-DC converter can isolate a faulted portion of the photovoltaic array while the remainder of the array continues producing power.

Hysteresis switch and electricity charging module using the same

ActiveUS20110241624A1Stable charging voltageHysteresis characteristicTransistorBatteries circuit arrangementsElectricityElectrical resistance and conductance
An electricity charging module using a hysteresis switch includes a storage capacitor that preliminarily stores electrical energy supplied from an external power source, a charging unit for preventing over-charging or over-discharging through monitoring of the charging state of the rechargeable battery, and a hysteresis switch that has a larger turn-on voltage level than the turn-off voltage level, and located between the storage capacitor and the charging unit, thereby electrically connecting or disconnecting the storage capacitor with the charging unit. The hysteresis switch includes a first voltage dividing resistor pair that divides the voltage of an external power source by the resistance ratio of the first voltage dividing resistor pair, a second voltage dividing resistor pair whose one end is connected to a positive electrode terminal of the external power source, a first switching device whose control terminal is connected to the junction of the voltage dividing resistors of the second voltage dividing resistor pair, a second switching device whose control terminal is connected to the junction of the voltage dividing resistors of the first voltage dividing resistor pair, and a resistor that is connected to the junction between the first electrode terminal of the second switching device and the junction of the voltage dividing resistors of the first voltage dividing resistor pair.

Multiple power source system and apparatus, motor driving apparatus, and hybrid vehicle with multiple power source system mounted thereon

In a multiple power source system of the present invention that has an inverter connected to a reactance, such as three-phase coils in a motor, a high voltage battery is connected with a low voltage battery via one transistor (Tr2) and one diode (D2) included in the inverter and one phase coil (U-phase coil) of the three-phase motor. The transistor Tr2 is turned on to make the electric current flow from the low voltage battery to the U-phase coil. The transistor Tr2 is subsequently turned off at a preset timing, so that the electric energy accumulated in the reactance, that is, the U-phase coil, flows through the diode D1 into the high voltage battery and thereby charges the high voltage battery. This arrangement enables the charging process from the low voltage battery to the high voltage battery without any complicated circuit structure for the voltage step-up. The three-phase motor may be unipolar driven with transistors connected to one side of the inverter. The arrangement of the present invention does not require any complicated structure, which undesirably increases the size of the multiple power source system, in order to ensure mutual supplement of the electric energy between electric systems having a large difference in voltage, for example, an electric system for driving a hybrid vehicle and an electric system for its control circuit.

Self-diagnostic circuitry for emergency lighting fixtures

Electronic self-test and/or self-diagnostic systems particularly useful with emergency lighting fixtures, including exit signage having light emitting diodes as light sources and unit emergency fixtures powered with lead-acid batteries, the systems perform testing and diagnostic functions on the circuitry, power supply, charger and lamping of such fixtures either by manual or automatic initiation. Testing functions are provided through use of a programmable microprocessor, the diagnostic circuitry not only monitoring operation of charger/transfer circuitry but also controlling the charger/transfer circuitry to enable alternate strategies for alleviation of a given failure. In emergency mode of a light emitting diode exit sign, a microprocessor-controlled two-stage inverter is employed not only to power the LED light source, but also to efficiently power the microprocessor. Power to the microprocessor is controlled by the microprocessor itself and can therefore be discontinued after appropriate operation until mains power is restored, thereby effectively reducing power consumption to zero. System operation can be flexibly configured through use of a two-wire serial link between modular elements of the system. Incandescent emergency unit fixtures due to high drain rates and output loads require emergency mode operation through use of lead-acid batteries, thereby requiring voltage controlled charging and relay transfer, the self-test and/or self-diagnostic circuitry of the invention used with emergency unit fixtures thus differing in various respects from the circuitry employed for the LED exit signage fixtures and primarily in the need to measure both charge and discharge currents, the circuitry having a larger dynamic range in addition to a capability of measuring both positive and negative currents.

Inductive Power Transfer System

An inductive power transfer system comprises a transmitter coil TX and a receiver coil RX spaced from the transmitter coil. A transmitter circuit comprises the transmitter coil and is in the form of a Class E amplifier with a first inductor Uchoke and a transistor in series between the terminals of a power supply, a first transmitter capacitor Cpar in parallel with the transistor between the first inductor and a power supply terminal, a primary tank circuit in parallel with the first transmitter capacitor, the primary tank circuit comprising the transmitter coil and a second transmitter capacitor Cres arranged in parallel with the transmitter coil, and a third transmitter capacitor Cser in series with the first inductor between the first transmitter capacitor and the primary tank circuit. The transistor is arranged to switch at a first frequency ωd and the capacitance of the second transmitter capacitor is selected such that the resonant frequency ωOTX of the primary tank circuit is greater than the first frequency. The receiver circuit comprises a Class E rectifier having a first receiver capacitor CL arranged in parallel with a load RL and a secondary tank circuit in parallel with the first receiver capacitor. The secondary tank circuit comprises the receiver coil and a second receiver capacitor Cres arranged in parallel or series with the receiver coil. A first diode Dr2 is provided between the secondary tank circuit and the first receiver capacitor. The capacitance of the second receiver capacitor is selected such that the resonant frequency ωoRX of the secondary tank circuit differs from the first frequency, so that the secondary tank circuit operates in semi-resonance and maintains some reactive impedance. The transmitter circuit is configured to vary the first frequency, in order to achieve a desired impedance of the primary tank circuit.
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