894 results about "Diode rectifier" patented technology

Control methods for resonant converters offer improved performance in resonant converters that operate with a wide input-voltage range or a wide output-voltage range (or both) by substantially reducing the switching-frequency range. Reduction in the switching frequency range is achieved by controlling the output voltage with a combination of variable-frequency control and time-delay control. Variable-frequency control may be used to control the primary switches of an isolated resonant converter, while delay-time control may be used to control secondary-side rectifier switches provided in place of diode rectifiers. The secondary-side control may be implemented by sensing the secondary current or the primary current (or both) and by delaying the turning-off of the corresponding secondary switch with respect to the zero crossings in the secondary current or the primary current.

A wireless resonant powering device (1) according to the invention comprises a first inductor winding (3), which is arranged to form a transformer (9) with the inductor winding (13) of the energizable load (11). The first inductor winding (3) is arranged to form a resonant circuit (5), which may comprise a suitable plurality of electric capacitances and coils. The components of the resonant circuit (5) are selected such that the magnetic energy received by the inductor winding (13) damps the energy flow in the resonant circuit so that the induced voltage in the inductor winding (13) is substantially constant and is independent of the magnetic coupling between the first inductor winding (3) and the inductor winding 13 at the operating frequency of the driving means (6). The resonant circuit is driven by the driving means (6), comprising a control unit (6c) arranged to induce an alternating voltage between a first semiconductor switch (6a) and a second semiconductor switch (6b). At the output of the transformer (9) an alternating voltage is generated, which is rectified to a DC-voltage by a diode rectifier, filtered by an output capacitance. The resonant circuit (5) is operable on its coupling independent point by the driving means (6). This figure schematically illustrates a situation, where a variable coupling between the first inductor winding (3) and the inductor winding (13) exists. The invention further relates to a wireless inductive powering device, an energizable load, a wireless system and a method for wireless power transfer.

The invention dsiclsoes a microgrid system with an asymmetric non-linear load and a power balancing control method. The system comprises a plurality of DG units connected in parallel and line impedors connected with all DG units. The line impedors are connected to a microgrid bus by PCC points. A three-phase balancing resistive load, an asymmetric linear load, and a diode rectifier non-linear load of a load unit are connected to the microgrid bus by PCC points. A measurement module for measuring voltage fundamental wave positive sequence and negative sequence components and harmonic wave components of the PCC points is also connected to the microgrid bus. The microgrid bus is connected with a 10-kV main power grid by a static switch and a transformer successively. According to the invention, reactive and harmonic power balancing of the microgrid is realized by using a selective virtual impedance based on the virtual fundamental positive and negative sequence impedance and the virtual variable harmonic impedance; a harmonic and unbalancing voltage compensation controller enables equal division of an unbalanced power and a harmonic power to be realized; and a problem of unbalancing of the harmonic wave and the voltage of the microgrid can be solved.

A cost effective circuit improves the cross regulation of multiple outputs converter, especially for that output chokes are coupled and a synchronous rectifier is applied to one of the outputs. A DC/DC converter includes a transformer having a primary winding and two secondary windings. The first secondary winding is coupled to a synchronous rectifier and a first output choke. The second secondary winding is coupled to a diode rectifier and a second output choke. The first output choke and the second output choke are coupled. A low power MOSFET switch is added to the diode rectifier for avoiding the diode rectifier operating in DCM when light loaded.

The invention belongs to the technical field of DC (Direct Current) power transmission, particularly a DC power transmission system with a function of unidirectionally transmitting a power. The DC power transmission system is characterized in that both ends of a diode rectifier are connected in parallel with low-power modularized multilevel converters; an AC (Alternate Current) end of the diode rectifier is connected with a sender system; a DC end of the diode rectifier is connected with a sender of a DC power transmission circuit; AC ends of the low-power modularized multilevel converters are connected with the sender system; DC ends of the low-power modularized multilevel converters are connected with the sender of the DC power transmission circuit; a DC end of a full-power modularized multilevel converter is connected with a receiver of the DC power transmission circuit; and an AC end of the full-power modularized multilevel converter is connected with a receiver system. The low-power modularized multilevel converters are used as active power filters to filter out a harmonic current generated by the diode rectifier, provide start power (such as service power) for the sender system when the sender system loses power, provide an AC voltage resource for the sender system.

A synchronous rectifier for use with a clamped-mode power converter uses in one embodiment a hybrid rectifier with a MOSFET rectifying device active in one first cyclic internal of the conduction/nonconduction sequence of the power switch and a second rectifying device embodied in one illustrative embodiment as a low voltage bipolar diode rectifying device active during an alternative interval to the first conduction/nonconduction interval. The gate drive to the MOSFET device is continuous at a constant level for substantially all of the second interval which enhances efficiency of the rectifier. The bipolar rectifier device may also be embodied as a MOSFET device. The subject rectifier may be used in both forward and flyback power converters.

Embodiments of a ground power unit are disclosed for providing power to a grounded vehicle, such as an aircraft. In accordance with certain embodiments, the ground power unit (GPU) accepts a wide range of AC input voltages and is capable of providing a range of DC output voltages. The GPU may include a switched rectifier that converts an AC input signal to a DC link signal. The DC link signal is then converted to a switched DC signal that simulates an AC-like sine wave using a high frequency DC-to-DC switching converter. A single-phase transformer modulates and isolates the switched DC signal, which is subsequently converted to a DC output signal using diode rectifiers coupled to the secondary winding of the transformer. The disclosed GPU may be controlled using a software-based control algorithm that controls the AC input parameters independently of the DC voltage parameters.

The invention relates to a hybrid parallel type high-voltage direct current traction power supply current transformer and a control method thereof. The hybrid parallel type high-voltage direct current traction power supply current transformer is characterized by comprising a set of pulse width modulation (PWM) rectifier units and a set of diode rectifier units, wherein both an input end of the PWM rectifier units and an input end of the diode rectifier units are connected with an alternating current electric network, and an output end of the PWM rectifier units and an output end of the diode rectifier units are connected in parallel to realize high-voltage direct current output. Because the PWM rectifier units and the diode rectifier units are connected in series, the direct current output voltage of the entire current transformer is improved, the power supply distance is prolonged, and the contact net loss is reduced. Meanwhile, equipment investment is reduced, and the reliability of a system is improved. The hybrid parallel type high-voltage direct current traction power supply current transformer and the control method thereof can be widely applied to urban railway transit traction power supply systems.

A portable battery charger that is powered by a gasoline, diesel, or propane engine. The portable device incorporates a recoil or electric starter and an engine throttle lever that can be used to vary the RPM of the engine and therefore the voltage/current output of the charger. The charger uses a permanent magnet alternator equipped with a belt tension adjustor arm and a heavy duty diode rectifier. The components of the charger (the engine and the alternator) are positioned on a wheeled, heavy-gauge steel, roll around cart that makes the charger easily portable. The two-wheeled cart includes an extended handle, allowing the user to move and steer the charger into position for use. Positioned on this handle is a control box with an anti-spark keyed switch that blocks any charging current from traveling through the charging cables until the switch is thrown. This control facilitates the safe hook-up of the charging clamps while the charger (engine) is running. The charger includes heavy duty cables between the alternator and the anti-spark control box, and additionally out from the control box to insulated clamps that are used to connect to the batteries. The control box additionally includes an ammeter and a voltmeter to indicate the charging current and voltage. The portable charger structured in this manner can be used to charge a non-specific number of batteries in parallel, typically in less than 2-4 hours depending on the size and state of the existing battery charge. The charger may also be used in the process of equalizing a bank of batteries to facilitate a reduction in stratification and sulfation.

A method of operating an electrical machine including: providing a brushless excitation system including a diode rectifier having at least one diode; sensing heat energy generated by the at least one diode; detecting a deviation of the generated heat energy from the at least one diode, and generating a signal indicating a failed or faulty diode if the deviation in generated heat energy exceeds a predetermined threshold deviation level.

A variable frequency drive comprises a diode rectifier receiving multiphase AC power and converting the AC power to DC power. An inverter receives DC power and converts the DC power to AC power to drive a load. A link circuit is connected between the diode rectifier and the inverter and comprises a DC bus to provide a relatively fixed DC voltage for the inverter. A link capacitor is across the bus. A soft charge circuit limits in rush current to the link capacitor. The soft charge circuit comprises an inductor in the bus and a resistor assist circuit across the inductor along with an anti-parallel clamping thyristor reverse connected also across the inductor.

The invention relates to a detecting device for detecting IGBT, comprising a shell and a testing circuit internally installed in the shell. The testing circuit consists of a power board, an I/O board,a central processing unit, a driver module, a micro breaker, an automatic coupling voltage regulator, a rectifying circuit, a filter circuit and an inverter circuit. A single-phase 220V, 50Hz alternating current power supply source is connected with the original edge of the automatic coupling voltage regulator in series; the secondary edge of the automatic coupling voltage regulator is connectedwith an AC voltmeter in parallel and inputs alternating voltage into a diode rectifier bridge module; the positive end of the automatic coupling voltage regulator is connected with a limit resistor inseries, is connected with a filter capacitor, a equalizing resistor and a DC voltmeter in parallel, and is connected with a fuse in series; +P and -N bus is connected with an inverse bridge formed byan IGBT module in parallel; the output end of the inverse bridge is connected with an output resistor; and the other end of the resistor is connected with the middle connecting point of the equalizing resistor. By detecting the PWM waveform of the output resistor, the detecting device can ensure the condition of the IGBT, has simple and easy measuring method, is time saving and labor saving, andis applicable to various IGBT detections.

A protected capacitor system/method implementing enhanced transient over-voltage suppression is disclosed. The system/method incorporates one or more surge suppression devices (SSDs) proximally located and in parallel with a capacitor structure to produce an overall protected capacitor structure having enhanced reliability and simultaneous ability to resist transient overvoltage conditions. The SSDs are formed from series combinations of transient voltage surge suppressors (TVSs) (metal oxide varistor (MOV), diode for alternating current (DIAC), and/or silicon diode for alternating current (SIDAC)) and corresponding shunt diode rectifiers (SDRs) and placed in parallel across a capacitor structure to locally suppress voltage transients across the capacitor structure in excess of the voltage rating of the capacitor structure. The parallel shunting TVB/SDR pairs may be integrated into a printed circuit board (PCB) assembly that is externally attached to the capacitor structure or encapsulated in an enclosure incorporating the capacitor structure.

A diode rectifier system for generator excitation includes a plurality of diode modules mounted on a heatsink and a coolant tube provided in the heatsink. The heatsink is electrically grounded. A method of cooling a diode rectifier system for generator excitation comprises providing a flow of liquid coolant in the coolant tube and electrically grounding the heatsink.

A new single-phase hybrid three-level rectifier comprises a single-phase uncontrollable diode rectifier bridge, a filter, a single-phase VIENNA rectifier bridge, a voltage and current sampling circuit, and a signal conditioning circuit. Through employing the above structure and a single-period control algorithm, the rectifier is simple in control method, is simple in structure, and just needs to collect an output voltage and an input current. The rectifier is very high in robustness, is high in power density, is large in power factor, is stable in output voltage, and is high in system reliability. Compared with a conventional single-phase rectifier, the rectifier provided by the invention can greatly improve the conversion efficiency, is large in application range, can greatly reduce the voltage stress of a power switching tube through employing the three-level structure, and can save a large amount of material resources and financial resources.

The invention relates to a high-voltage inverter sharing a direct current (DC) bus. The high-voltage inverter sharing the DC bus comprises a charging circuit, a phase-shifting transformer, three-phase diode rectifier bridges, a high voltage DC bus and an inverter based on multi-media card (MMC) topology. The primary side of the phase-shifting transformer is connected with a power grid through the charging circuit, each subsidiary side output winding of the phase-shifting transformer is connected with the three-phase diode rectifier bridge, the output capacitors of each diode rectifier are connected in series to form the high voltage DC bus, the high voltage DC bus is connected with the public DC end of one inverter or multiple inverters based on MMC topology, and the output ends of the inverters are connected the electric motor to be detected, and the mixed frequency test and the frequency control function of the electric motor is achieved. The topologic scheme of the high-voltage inverter sharing the DC bus meets the requirements of the electric motor test station of a weak grid end, multiple-unit output of the phase-shifting transformer with multiple windings is used, the DC bus formed by the series connection of the diode rectifying capacitors is used to store the energy extracted and fed back when the electric motor mixed frequency test is carried out, the energy is no longer loaded by the power grid, and therefore the pollution to the power grid caused by the electric motor test is eliminated.

The invention discloses a non-contact electrical energy transmission device with self-adaptive power factor correction and a control method, the device adopts the AC (alternating current)/DC (direct current)/AC (alternating current) energy conversion way, the structure of a diode rectifier bridge plus a half-bridge double-switch is used for realizing the functions of active power factor correction and resonance inversion, and the structure of a three-order resonant network is further utilized for realizing the functions of reactive power compensation and load self-adaption. The control method of the device is simple, and only a driving signal with a constant frequency and constant duty cycle needs to be imposed on the half-bridge double-switch. The problems of small output power, great harmonic pollution, poor load applicability and the like in the non-contact electrical energy transmission technology can be solved by the device and the control method, and the device and the control method can be widely used in moving and lifting equipment of plants, mining and transporting equipment of coal mines, electrical power and subway locomotives, factories and mines with flammable and explosive gas and other various occasions.

The invention discloses a gallium nitride based schottky diode with a field plate structure, wherein the periphery of a schottky metal electrode is provided with a layer of an insulating medium film, and the schottky metal electrode is extended to the upward side of the insulating medium film and covers part of the insulating medium film, namely a circle of metal-insulating medium layer-semiconductor (MIS) field plate structure is formed on the periphery of the schottky metal electrode; and the insulating medium layer of the field plate structure comprises at least one layer of an insulating material with a high dielectric constant, the thickness of the insulating material is between 0.01 and 2 microns, and the dielectric constant is bigger than 6. The gallium nitride based schottky diode comprises an ohmic contact layer, a GaN active layer, an insulating medium field plate, the schottky metal electrode and an ohmic contact electrode. Compared with a conventional structure device, a rectifier using the GaN schottky diode provided with the high dielectric constant material field plate has evener electric field distribution and higher reverse breakdown voltage.

A power supply for converting AC to a regulated DC output current, utilizing two serial switched mode power supplies, the first providing an intermediate DC output voltage with only moderate ripple properties, this output being input to the second, which operates as a DC/DC converter to provide the desired output with low ripple and good regulation. The diode rectifier assembly has no reservoir/smoothing capacitor, or one of much smaller capacitance than in prior art power supplies. The large resulting rectifier output ripple is overcome by use of the two power supply units, at least the first having a smoothing capacitor at its output. A majority of the energy stored in this capacitor is utilized during each AC half cycle. Such power supplies also provide improved hold-up times. The power supply is also constructed to have low standby power consumption, by use of a double burst configuration.