660 results about "Ac circuit" patented technology

The invention comprises use of Dynamically Switchable Bypass (DSB) elements in association with one or more Light Emitting Diodes (LEDs) in arrays for illumination circuits to provide rugged, reliable lighting. The DSBs are selected from Transient Voltage Suppressors, including Silicon, Metal Oxide Varistors, and Multi Layer Varistors as well as Zener Diodes. The DSBs are not used as circuit protecting devices, but rather as alternative paths for electric current to bypass failed LEDs. Bi-directional TVSs are used as alternative electric paths for circuits using Alternating Current (AC) and parallel LED arrays that light on both phases of AC. Zener Diodes are used in parallel to, but in the opposite polarity orientation to, one or more LEDs in DC or rectified AC circuits. The inventive paired DSB / LED elements overcomes the black-out problems of prior series LED illumination systems, making possible the use of robust LEDs in illumination systems where reliability, long life, low power consumption, low heat output, resistance to shock, vibration, and humidity, and self-diagnosis are important. The DSB elements have breakdown voltages slightly higher than the LED(s) they support, so that when an LED fails, the conduction through the DSB begins. Because the conduction voltage of the DSB so nearly matches the conduction voltage of the LED(s), the remainder of the circuit continues to function as normal. The system is self-diagnostic in that any LED failure presents itself as a dark LED rather than as a whole string of dark LEDs. DSBs may be used with incandescent bulbs.

An integrated system of renewable energy management and storage that receives direct current generated from renewable sources and intelligently routes the electrical power between a direct current circuit and an alternating current circuit, and at the same time determines the optimal routing for electrical storage based on usage and demand. Electrical power from the direct current circuit can be converted to alternating current electrical power and supplied to the alternating current circuit, or vice versa. Electrical power from either the direct current circuit or the alternating current can be stored in the energy storage subsystem. Electric energy can be further converted to and stored as gaseous hydrogen and can supply for other applications that consume gaseous hydrogen. The system can work with a connection to a utility grid or as a stand-alone system.

An LED light string employs a plurality of LEDs wired in block series-parallel, where the one or more series blocks, each driven at the same input voltage or rectified AC input voltage as the source voltage (110 VAC or 220 VAC), are coupled in parallel. This voltage matching requirement for direct AC drive places fundamental restrictions on the number of diodes on each diode series block, depending on the types of diodes used. The same method that apply to matching the sum of the LED lamps (VAC values) to the AC input, or applied voltage in an AC circuit apply to matching the sum of the LED lamps (VP values) to the full-wave or half-wave rectified AC (VP) voltage applied. Filtering capacitors may also be employed.

The invention relates to an electric secondary AC circuit detection method which comprises the following steps: before a power plant machine set is started, a low-voltage short-circuit point or a short-circuit bogie is input; three-phase 380 V voltage is added at the high-voltage side of a booster station to form a circuit by means of the impedance of a transformer and a generator; current amplitude and phase are measured through a current detecting apparatus to check polarity and transformation ratio in advance; all current protective directions such as generator differential motion are measured. When a neutral point is not connected, a short-circuit point is made at a high plant transformer low-voltage side, and the three-phase 380 V voltage is added at the neutral point of the generator, thereby realizing overall checkup of a generator AC circuit; then, the three-phase 380 V voltage is converted into one-phase voltage or two-phase voltage to carry out overall checkup of a zero sequence circuit. The detection method can check all CT and PT circuits of a generation-transformer group before power transmission; moreover, all protection directions of the generation-transformer group are checked in advance, thereby saving time and fuel oil along with economical efficiency, environmental protection and safety. The electric secondary AC circuit detection method can check secondary circuits such as the transformer and the bus differential protection of a transformer substation.

The invention discloses a combined splint microelectrode type micro-fluidic dielectrophoresis cell separation and enrichment chip and relates to a micro-fluidic chip which is applied in cell sample separation and enrichment, a dielectrophoresis (DEP ) splint combined type electrode is obtained through depositing gold film on the surface of glass, and the electrode can be connected with a corresponding external connected low pressure high frequency ac circuit to realize DEP separation and enrichment process control. The combined splint microelectrode which is provided by the invention designs that the functions of on-line separation and on-line enrichment of sample such as cells and the like are effectively integrated on a chip, which realizes organic combination between the micro-fluidic chip technique and the microelectrode principles, and the chip can be applied and can realize the separation and the enrichment of various cells and bacterium.

An apparatus for providing phase rotation for a three-phase AC circuit. The apparatus comprises three phase input terminals and three phase output terminals, where a first phase input terminal is coupled with a third phase output terminal; a second phase input terminal is coupled with a first phase output terminal; and a third phase input terminal is coupled with a second phase output terminal.

A self-contained and encapsulated AC to Voltage supplying module containing a complete set of AC circuitry components therein and directly connecting the components to the AC voltage source, an inrush protection circuit, a DC-DC converter and power control circuits which enable the encapsulation of AC and DC components within a module being directly mountable and DC electrically connected to a printed circuit board assembly.

A method and apparatus for providing AC voltage measurements. The apparatus comprises an AC voltage monitor for determining at least a first and a second voltage representing an AC voltage of an AC circuit, generating a serial data stream frame comprising data representing the at least a first and a second voltage, and transmitting the serial data stream frame.

Power is transmitted based on magnetic resonance from a feeding coil L2 to a receiving coil L3. An adjustment circuit 104 of a wireless power receiver 118 is supplied with a first AC power received by the receiving coil L3. An adjustment circuit 104 includes a DC circuit 106 and an AC circuit 150. The DC circuit 106 converts the first AC power into DC power. The AC circuit 150 converts the DC power into a second AC power. The adjustment circuit 104 outputs the DC power and second AC power simultaneously or selectively through separate channels.

A method of testing live AC circuits for neutral-ground, neutral-isolated ground, and isolated ground-ground faults, involves measuring impedances of circuit portions, including hot-neutral, neutral-ground, neutral-ground and isolated ground loops. In general either a test current generating a driving voltage is used, or in the case of hot-neutral, a load current generating a load voltage, and the voltage without current are use to measure voltage drop. These voltages are proportionate to the impedances of the circuits, which are expressed as ratios indicating the presence of faults. The method is reliable, despite much variation in circuit characteristics, including oversized neutral, shared neutral same phase, shared neutral opposed phase, supply line impedance, and high impedance grounds, it is easily able to detect faults across conductors and shared neutral loads.

A system for supplying high voltage direct current for Transcranial Magnetic Stimulation (TMS) devices under program control features a rate input that commands the power supply to charge the discharge capacitors at a fixed rate until a programmed target voltage is achieved. This reduced demand spikes to the AC line when operating the TMS device, and may allow the TMS device to operate from a lower-rated AC circuit than would otherwise be possible.

An arc fault circuit interrupter which protects an AC circuit subjected to a possible arcing fault includes a sensor which produces a signal that can be evaluated to see if it is associated with arc fault current. The evaluation is done by a discrimination circuit which identifies a characteristic of the sensor signal associated with cessations of the arc fault current. An accumulator counts the number of occurrences of the cessations, and if the number of cessations counted within a predetermined time interval exceeds a predetermined number, the arc fault circuit interrupter interrupts the AC circuit.

The invention discloses a mixed clamping back-to-back multi-level AC-DC-AC switching circuit. The mixed clamping back-to-back multi-level AC-DC-AC switching circuit comprises two groups of multi-level switching circuits and a direct current bus capacitor link connected with the two groups of multi-level switching circuits; and the level number of the direct current bus capacitor link is more than or equal to 4. By the mixed clamping back-to-back multi-level AC-DC-AC switching circuit, the dynamic self-balance between all direct current bus capacitors and clamping capacitors can be realized and equal capacitor voltage can be obtained so that the champing capacitors and the direct current bus capacitors complete multi-level boost output and a good condition for the expansion of the capacitance of direct current bus capacitors is created at the same time. The mixed clamping back-to-back multi-level AC-DC-AC switching circuit bears a high-power high-voltage load on the premise of guaranteeing system reliability and good harmonic output characteristics, is flexible in control, quite low in loss, has efficient performance, can realize bidirectional flow and mutual control compensation of reactive power and active power, and is very suitable for alternating current speed regulation or a power grid interconnection technique of different distributed power generating systems.

A selectable source input power supply is disclosed. According to one embodiment, a power supply is provided comprising an input stage including an input connector to couple the power supply to either of an AC input voltage or a DC input voltage, and an actuatable input switch to determine which of the AC input voltage and the DC input voltage is coupled to the power supply, to couple the input stage to an alternating current path in response to a determination that the AC input voltage is coupled to the power supply, and to couple the input stage to a direct current path in response to a determination that the DC input voltage is coupled to the power supply.

Embodiments of a modular air conditioning (AC) unit include a base unit, a blower mounted to the base unit, and at least one heat exchanger module assembled to the base unit and communicatively coupled to the blower to form a modular AC circuit. The modular AC unit also includes a controller communicatively coupled to at least one component of the modular AC circuit and adapted to independently control operation of each of the components of the modular AC circuit.

A high voltage DC circuit breaker includes a semiconductor switching assembly in series with a mechanical switch. When the semiconductor switching assembly is switched off due to a current fault, a residual current flowing through arresters of the semiconductor switching assembly is switched off by the mechanical switch. A capacitor arranged parallel to the mechanical switch leads to passive resonance effects, which in turn induce current zero crossings in its arc. The current zero crossings allow for reliable extinguishing of the arc. The mechanical switch can be an AC circuit breaker.

An exemplary embodiment of an alternating valley switching controller is provided. The alternating valley switching controller includes a valley detection circuit and an alternating circuit. The valley detection circuit is coupled to an auxiliary winding of a transformer to generate a valley-detection signal. The alternating circuit alternates a plurality of switching periods of a switching signal according to a blanking-window signal and the valley-detection signal. The blanking-window signal switches between a first voltage level and a second voltage level in the plurality of switching periods. The plurality of switching periods includes at least two first periods and at least two second periods which occur alternately in response to the first voltage level and the second voltage of the blanking-window signal.

The invention provides an intelligent marshalling combination switch, comprising an AC electronic switch, a magnetic latching relay and a control circuit. The intelligent marshalling combination switch is characterized in that the control circuit is connected with at least a group of combination switches; the structure of the combination switch is that the AC electronic switch is connected in parallel with the magnetic latching relay with one-way contacts; the parallel end is connected in series with the magnetic latching relay with bidirectional contacts and the other parallel end is connected with one end of a single-phase capacitor and one end of a discharge coil; the other end of the single-phase capacitor and the other magnetic latching relay with bidirectional contacts are connected in series with each other and are connected into a return circuit. The intelligent marshalling combination switch can lead the single-phase capacitor to be freely switched without disturbance between the phase lines of the three-phase AC circuit and between the phase line and the zero line of the three-phase circuit, realizes the star-delta unequal arbitray connection of the single-phase capacitor under the control of a controller, completes adjusting the asymmetrical active load of the transformer and compensating the reactive loads at the same time, leads the transformer to be changed from the asymmetrical running to the symmetrical running, saves the power energy, and leads the power supply to have high quality and reliable running.

The embodiment of the invention provides a dual-mode current collecting system and method. The system comprises an alternating current-direct current pantograph, an alternating current-direct current voltage transformer, an alternating current-direct current change-over switch, a direct current circuit, an alternating current circuit and a switching controller. The alternating current-direct current voltage transformer is connected with the alternating current-direct current pantograph. The alternating current-direct current change-over switch is connected with the alternating current-direct current pantograph and the direct current circuit or the alternating current circuit. The switching controller is connected with the alternating current-direct current voltage transformer and the alternating current-direct current change-over switch. Both the direct current circuit and the alternating current circuit are connected with a traction converter. The switching controller is used for acquiring whether received voltage is an alternating current or a direct current and controlling the alternating current-direct current change-over switch to be connected with the direct current circuit or the alternating current circuit according to acquisition results, so that the direct current or the alternating current is provided for the traction converter. The dual-mode current collecting system and method can be suitable for train tracks in an alternating current mode and a direct current mode at the same time, and the operation range of a train set is expanded.

A system and method for transmitting data within a utility substation in which a utility substation power line coupled to a voltage source is used to power a gateway and one or more network devices. The gateway generates a network signal that is communicated onto the power line by a first coupler and received by a second coupler. The second coupler then transmits the received network signal to one or more network devices configured to collect data relating to the operation of the utility substation.

The invention relates to a method for removing instantaneous short circuit earth faults of a direct current line of a flexible direct current power transmission system, and belongs to the technical field of power electronics. Requirements of an electric power system on the fault removing capability of the flexible direct current power transmission system is considered. By means of the structural characteristics of the flexible direct current power transmission system and the characteristic that an ac circuit breaker can break a direct current the magnitude of which is lower than a certain scope, the ac circuit breaker is connected in series between a converter transformer neutral point and an earth resistor, and plays a role in breaking direct current fault currents. By employing the ac circuit breaker, the problem that the whole flexible direct current power transmission system needs to be shut down in order to remove instantaneous short circuit earth faults of the direct current line is solved. The method is advantaged by being economic and reliable, and being mature in technology, simple to implement and excellent in performance, and can be applied to practical engineering of flexible direct current power transmission.