Abstract: An apparatus includes an enclosure and a coil assembly in the enclosure. The coil assembly includes a magnetic core and a coil disposed on the magnetic core. The magnetic core is positioned adjacent a wall of the enclosure such that a direction of a main flux path in the magnetic core is through at least one portion of the wall having a magnetic permeability greater than air. Such an arrangement may be used for a wireless power receiver unit configured to be installed in an equipment rack in data center applications.

Abstract: A primary coil can be inside the recess, where the primary coil is wound around the center of the recess. A secondary magnetic core can include a protruding center portion that is configured for insertion into the center of the recess so that the protruding center portion overlaps the primary magnetic core side wall and is configured to provide separation between the primary magnetic core and the secondary magnetic core. A secondary coil can be wound around the protruding center portion of the secondary magnetic core.

Abstract: A photovoltaic inverter system and an operation method thereof are provided. The photovoltaic inverter system includes photovoltaic modules, DC/DC converters, at least one direct current combiner device and a centralized inverter. An input signal or an output signal of each of the DC/DC converters is sampled by the DC/DC converter, and a loop process is performed by the DC/DC converter on the input signal or the output signal to maintain the input signal or the output signal at a preset value, so as to keep the output power of the photovoltaic module to be the maximum output power, thereby solving the problem of the series-parallel mismatch of a photovoltaic array due to being shaded or aging of a photovoltaic module. In addition, the photovoltaic inverter system can include only one centralized inverter. Therefore, the cost is reduced compared with photovoltaic inverter systems in the conventional technology.

Abstract: A primary coil can be inside the recess, where the primary coil is wound around the center of the recess. A secondary magnetic core can include a protruding center portion that is configured for insertion into the center of the recess so that the protruding center portion overlaps the primary magnetic core side wall and is configured to provide separation between the primary magnetic core and the secondary magnetic core. A secondary coil can be wound around the protruding center portion of the secondary magnetic core.

Abstract: A cooperative control method and device for a photovoltaic optimizer and a photovoltaic inverter are provided. The cooperative control method and device are applicable to a grid-connected photovoltaic system including N photovoltaic components, N photovoltaic optimizers and one photovoltaic inverter. The N photovoltaic components are respectively connected to input sides of the N photovoltaic optimizers, and output sides of the N photovoltaic optimizers are connected to a DC side of the photovoltaic inverter, N being an integer greater than or equal to 1. The cooperative control method includes determining an operation parameter of the grid-connected photovoltaic system; judging whether the operation parameter is lower than a preset value; and adjusting a voltage of the DC side of the photovoltaic inverter until the operation parameter is not lower than the preset value, in a case that the operation parameter is lower than the preset value.

Abstract: A cascaded multi-level inverter system, a modulation method and a controller for the same are provided. The method includes performing a maximum power point tracking control based on a voltage signal and a current signal of each DC source and a voltage signal and a current signal of the power grid obtained by sampling, calculating a first modulation signal for suppressing power imbalance, and outputting the first modulation signal to each inverter unit; and calculating, based on the calculated reactive current instruction value, the calculated active current instruction value, and a current signal of the reactive compensation device obtained by sampling, a second modulation signal for causing an output power factor of the cascaded multi-level inverter system to be 1, and outputting the second modulation signal to the reactive compensation device.

Abstract: An uninterruptible power supply (UPS) includes a rectifier circuit coupled to an AC input and configured to produce a DC voltage between first and second DC buses, an inverter circuit coupled to the first and second DC buses and configured to produce an AC voltage at the AC output. The UPS further includes an auxiliary power circuit comprising third and fourth DC buses configured to be coupled to a DC power source and third and fourth capacitors coupled between respective ones of the third and fourth DC buses and the neutral and respective first and second switches configured to couple and decouple respective ones of the third and fourth DC buses to and from respective ones of the first and second DC buses. The third and fourth capacitors may have capacitances greater than capacitances of the first and second capacitors.

Abstract: An AC-DC photovoltaic device is provided, including: a photovoltaic module, a direct current side capacitor, a DC-PWM power switching circuit and a controller. The direct current side capacitor is connected in parallel with an output terminal of the photovoltaic module. An input terminal of the DC-PWM power switching circuit is connected with the output terminal of the photovoltaic module. The DC-PWM power switching circuit includes a controllable switch transistor. The controller is configured to output a switch control signal to control a switching state of the controllable switch transistor in the DC-PWM power switching circuit, to control the DC-PWM power switching circuit to output a direct current PWM wave in a case that the switch control signal is a direct current modulation signal, and output an alternating current PWM wave in a case that the switch control signal is an alternating current modulation signal.

Abstract: A cascaded H-bridge inverter and a method for handling a fault thereof are provided. An output voltage or an output power of each of N solar panels is detected by a controller. In a case that the output voltage of at least one of the N solar panels is lower than a preset voltage, or that the output power of at least one of the N solar panels is lower than a preset power, the controller controls a corresponding switching device to be switched off, and changes a set value of a voltage across a capacitor in the direct current side. Then, the controller controls a corresponding H-bridge module to perform inverting by taking the set value of the voltage across the capacitor in the direct current side as an input value, so that a total output modulation voltage of the cascaded H-bridge inverter meets a preset condition.

Abstract: Provided are a cascaded photovoltaic grid-connected inverter, a control method and a control device for the same. The method includes: determining whether at least one of inverter units of the cascaded photovoltaic grid-connected inverter is over-modulated; injecting a reactive current to a power grid to make a grid-connected current effective value greater than or equal to ?{square root over (2)}*idcmin, in a case that at least one of the inverter units is over-modulated; determining a voltage U0 required for grid connection for the cascaded photovoltaic grid-connected inverter corresponding to a current grid-connected current effective value; and adjusting an output active voltage of each of the inverter units according to Ujd=Pj/P0*U0d, and adjusting an output reactive voltage of each of the inverter units in a case that none of the inverter units is over-modulated.

Abstract: An apparatus includes an enclosure and a coil assembly in the enclosure. The coil assembly includes a magnetic core and a coil disposed on the magnetic core. The magnetic core is positioned adjacent a wall of the enclosure such that a direction of a main flux path in the magnetic core is through at least one portion of the wall having a magnetic permeability greater than air. Such an arrangement may be used for a wireless power receiver unit configured to be installed in an equipment rack in data center applications.

Abstract: A forward-flyback DC-DC converter topology includes a transformer, a main switch, a clamp circuit, first and second rectifying switches, an LC resonant circuit and an output capacitor; a primary winding of the transformer and the main switch are connected in series between a first input terminal and a second input terminal, the clamp circuit constituted by a clamp capacitor and a clamp switch connected in series is connected in parallel with the primary winding or with the main switch, a secondary winding of the transformer includes a forward winding and a flyback winding, a terminal of the primary winding through which current flows into is a dotted terminal of the primary winding, and a connecting mode of a secondary side of the transformer is: the dotted terminal of the forward winding being connected with a first output terminal via the first rectifying switch, a dotted terminal of the flyback winding being connected with a second output terminal via the second rectifying switch, the LC resonant circuit b

Abstract: A primary coil can be inside the recess, where the primary coil is wound around the center of the recess. A secondary magnetic core can include a protruding center portion that is configured for insertion into the center of the recess so that the protruding center portion overlaps the primary magnetic core side wall and is configured to provide separation between the primary magnetic core and the secondary magnetic core. A secondary coil can be wound around the protruding center portion of the secondary magnetic core.

Abstract: The present invention relates to an online uninterruptible power supply topology. A single-phase topology comprises a main circuit and an auxiliary circuit.

Abstract: Wireless power transfer systems include at least one foil-type transmitter/receiver coil with a plurality of turns, which is configured to reduce eddy current losses therein when energized to conduct an alternating current that supports inductive power transfer including coil-to-coil power electrical transfer, inductive heating, etc. The plurality of turns includes at least an outermost turn with a first arcuate-shaped corner having a concave inner surface, which faces an immediately adjacent one of the plurality of turns. The immediately adjacent one of the plurality of turns may also have a second arcuate-shaped corner with a concave inner surface facing an innermost one of the plurality of turns. The first arcuate-shaped corner may have a non-uniform radius of curvature and/or an innermost one of the plurality of turns may have an arcuate-shaped corner, which is a mirror image of the first arcuate-shaped corner when the coil is view in transverse cross-section.

Abstract: Wireless power transfer systems include at least one foil-type transmitter/receiver coil with a plurality of turns, which is configured to reduce eddy current losses therein when energized to conduct an alternating current that supports inductive power transfer including coil-to-coil power electrical transfer, inductive heating, etc. The plurality of turns includes at least an outermost turn with a first arcuate-shaped corner having a concave inner surface, which faces an immediately adjacent one of the plurality of turns. The immediately adjacent one of the plurality of turns may also have a second arcuate-shaped corner with a concave inner surface facing an innermost one of the plurality of turns. The first arcuate-shaped corner may have a non-uniform radius of curvature and/or an innermost one of the plurality of turns may have an arcuate-shaped corner, which is a mirror image of the first arcuate-shaped corner when the coil is view in transverse cross-section.

Abstract: Three-level T-type power converters include a totem-pole arrangement of first and second wide bandgap field effect transistors, which are electrically connected in common at an output node of the converter. A pair of power transistors is provided along with a totem-pole arrangement of first and second capacitors. The power transistors are electrically connected in an opposing series relationship between the output node and a reference node. The first and second capacitors are electrically connected in common at the reference node. The first capacitor has a first terminal electrically connected to a first terminal of the first wide bandgap field effect transistor and the second capacitor has a second terminal electrically connected to a second terminal of the second wide bandgap field effect transistor.

Abstract: A forward-flyback DC-DC converter topology includes a transformer, a main switch, a clamp circuit, first and second rectifying switches, an LC resonant circuit and an output capacitor; a primary winding of the transformer and the main switch are connected in series between a first input terminal and a second input terminal, the clamp circuit constituted by a clamp capacitor and a clamp switch connected in series is connected in parallel with the primary winding or with the main switch, a secondary winding of the transformer includes a forward winding and a flyback winding, a terminal of the primary winding through which current flows into is a dotted terminal of the primary winding, and a connecting mode of a secondary side of the transformer is: the dotted terminal of the forward winding being connected with a first output terminal via the first rectifying switch, a dotted terminal of the flyback winding being connected with a second output terminal via the second rectifying switch, the LC resonant circuit b

Abstract: A pre-stage boost device, comprising: a selector switch (130); a power factor inductor (140), a common boost circuit (150), a rectifier circuit (160), and a filter circuit (170). The common boost circuit includes: connected in series a first switch (Q1), a second switch (Q2) and a third switch (Q3). The rectifier circuit includes two rectifier diodes (D5, D6). The filter circuit includes connected in series two capacitors (C1, C2). Maximum multiplexing of the main power components under the battery mode and the commercial power mode is achieved by this invention, the cost to performance ratio is also improved.

Abstract: An active clamped-mode DC-to-DC converter with synchronous rectifiers and a combined transformer-inductor device is provided. The power converter includes a combined transformer-inductor device having a primary winding, a secondary winding, and an auxiliary winding where the primary and the secondary windings perform a transformer function and the auxiliary winding performs an output filter function, a switching circuit for periodically providing a positive voltage to the primary winding and a negative voltage to reset the primary winding, and a synchronous rectification circuit connected for enabling conduction from the secondary winding to an output port in which the auxiliary winding is coupled between the output port and the synchronous rectification circuit for providing an inductance to filter an output signal.