Abstract: A power converter includes a power module, a terminal block, a housing that houses the power module and the terminal block, and a bus bar that electrically connects the power module and a conductive member connected to an electric component outside the housing. The terminal block is a member that electrically connects the bus bar and the conductive member, has a first surface, a second surface facing the first surface, and a connection surface that connects the first surface and the second surface, and includes a fastening member provided on the second surface to be movable with respect to the terminal block. The bus bar is formed between the power module and the conductive member to surround the first surface, the connection surface, and the second surface of the terminal block, and is connected to the conductive member on the second surface via the fastening member.

Abstract: A power converter includes a power conversion controller configured to determine whether or not an output terminal is misconnected to a system power supply based on a current between a power converter and the output terminal and a voltage between the power converter and the output terminal, and to perform a control to stop power conversion in the power converter when determining that the output terminal is misconnected to the system power supply.

Abstract: A method for operating a PV system that is integrated into a power system connected to a power grid includes determining a voltage operating point for the PV system based on a maximum power point tracking (MPPT) algorithm. If an available power output of the PV system can be provided to the power grid, the method includes operating the PV system based on the voltage operating point. If the maximum available power output of the PV system cannot be provided to the power grid, the method includes applying a voltage step to the voltage operating point to drive a power output of the PV system towards an external power constraint.

Abstract: A power conversion system includes a first power converter and a second power converter which are capable of converting an alternating-current power into a direct-current power or converting a DC power into an AC power. The first power converter is interconnectable to a first AC system via a first AC circuit breaker. The second power converter is interconnectable to a second AC system via a second AC circuit breaker. A first DC terminal of the first power converter and a second DC terminal of the second power converter are connectable. The first power converter begins operation prior to the second power converter. A first control device controls a voltage of the first DC terminal, based on a status of the second power converter sent from a second control device.

Abstract: A photovoltaic solid-state transformer, a photovoltaic inverter system and a bidirectional high-voltage transformer are provided. The photovoltaic solid-state transformer includes: multiple single phase modules and a filter. Each of the single phase modules includes multiple multiple-output isolated DC/DC converters and multiple cascade DC/AC modules, where each of the multiple-output isolated DC/DC converters includes a DC/AC module, a high frequency transformer and multiple AC/DC modules. The multiple single phase modules are connected to the grid via the filter in a star connection or a delta connection. The DC/DC converters and the cascade DC/AC modules are simple logical switches and have conversion efficiency higher than 99%, such that the photovoltaic solid-state transformer has a reduced volume, and an improved overall efficiency higher than 98.5%.

Abstract: Methods, apparatus, and systems are disclosed to drive a transistor. An example apparatus includes a regulator including a first input terminal adapted to be coupled to a control terminal of a transistor, a first output terminal, and a second output terminal, a first stage including a first input terminal coupled to the first output terminal of the regulator and an output terminal adapted to be coupled to the control terminal of the transistor, and a second stage including an input terminal coupled to the second output terminal of the regulator, and an output terminal adapted to be coupled to the control terminal of the transistor.

Abstract: Intelligent safety disconnect switching methods and arrangements for PhotoVoltaic (PV) panels are disclosed. A switching device that is connected between a PV panel and a PV panel string detects a low current condition or an arc fault condition in the PV panel string. The switching device is automatically controlled to disconnect the PV panel from the PV panel string responsive to detection of the low current condition or the arc fault condition. Switching device control could also be responsive to a disconnect command. For example, such a command could be generated by a grid sensor responsive to determining that an inverter, to which the PV panel string is connected, is not connected to an electrical grid.

Abstract: An islanding operation is detected appropriately through interconnection to the power grid which may have various characteristics. A detection apparatus is provided, which includes a frequency parameter calculation unit configured to calculate frequency parameters according to frequencies of power supplied by a power supply, a deviation parameter calculation unit configured to calculate a deviation parameter according to a frequency deviation based on the frequency parameters in a first term and the frequency parameters in a second term earlier than the first term, an islanding operation detection unit configured to detect whether the power supply is in an islanding operation based on the deviation parameter, and a time gap change unit configured to change a time gap between the first term and the second term.

Abstract: A medium-high voltage energy conversion system, and a control method and a controller therefor are provided. In the control method, an operation state of the medium-high voltage energy conversion system is acquired. In a case that the system is in a normal operation state, the system is controlled to operate in a first direct circuit current source mode. In a case that the system is in a first fault state in which a direct current grid voltage drops, the system is controlled to operate in a direct current voltage source mode. In a case that the system is in a second fault state in which a direct current grid voltage is in an overvoltage state, the system is controlled to operate in a second direct circuit current source mode.

Abstract: Provided is a power detection circuit for tracking a maximum power point of a solar cell. The power detection circuit includes: an average voltage extracting unit which extracts an average voltage VPV,LPF from an external voltage VPV input from an external energy source; a ripple voltage extracting unit which extracts a ripple voltage including current information of the external voltage VPV from the external voltage VPV; a voltage-time converter which generates a ramp voltage VRAMP changing at a predetermined rate and converts the average voltage VPV,LPF and the ripple voltage into corresponding time information ?t1 and ?t2 based on the ramp voltage VRAMP; a time-digital converter which converts the time information ?t2 for the ripple voltage into a digital code t2 [n:0]; and a time multiplier which multiplies the digital code t2 [n:0] and the time information ?t1 for the average voltage VPV,LPF to output a specific voltage value.

Abstract: An energy supply system and electrical outlet are provided. An energy supply system includes an electrical power source connected to an inverter device for forming a local power grid. The electrical outlet includes frequency measuring means for measuring the frequency of the electrical power feed into said local power grid by said inverter device and power control means for controlling said electrical power provided to a load by said electrical outlet dependent on the measured frequency.

Abstract: A diagnosis system including: a power collection unit configured to couple a plurality of photovoltaic cell arrays, each including photovoltaic cells, in parallel; a control unit; and a monitoring unit, the monitoring unit being configured to: estimate a solar radiation amount and an operating temperature of the photovoltaic cell arrays based on the current value measured by a first ammeter in the control unit and the voltage value measured by the first voltmeter in the control unit by using an expression expressing a relationship between the solar radiation amount, the operating temperature, and a number of photovoltaic cells, and an output current; correct the estimated values so as to match the current values measured by second ammeters in the power collection unit by using the expression; and calculate a theoretical current value of each of the photovoltaic cell arrays based on the corrected values by using the expression.

Abstract: An apparatus and corresponding systems and methods for managing electric power, particularly a transformer system and method, and more specifically a transformer for transforming direct current to alternating current. An example apparatus includes a chamber configured to contain plasma. The apparatus includes input electrodes disposed at least partially within the chamber, and configured to receive direct current input into the chamber. The input electrodes are configured to cause the input direct current to induce motion in the plasma. Motion induced in the plasma transforms current flowing there-through. Output electrodes extend from the chamber, which output electrodes may rotated in a controlled manner. The output electrodes conduct a three or one phase alternating current, from the induced motion in the plasma, for delivery from the chamber.

Abstract: In one embodiment, a network protector for a spot network includes a circuit breaker and a network protector relay coupled to the circuit breaker. The network protector relay is structured and configured to have network protector relay non-sensitive trip settings for controlling operation of the circuit breaker that will cause the network protector to remain closed when: (i) an angular difference (±) between a transformer phase-to-neutral voltage of the first feeder branch and a transformer phase-to-neutral voltage of the second feeder branch is less than or equal to a first threshold value, and (ii) a magnitude difference (±) between the transformer phase-to-neutral voltage of the feeder branch and the transformer phase-to-neutral voltage of the second feeder branch is less than or equal to a second threshold value.

Abstract: A system includes a controller programmed to control an inverter to supply a power grid with a maximum amount AC electrical power while operating within an operating area that is pre-defined based on hardware limitations of the inverter. The system allows the inverter to operate with a variable low-DC voltage input into the inverter as opposed to a preset threshold DC voltage, thereby maximizing the amount of power the inverter supplies to a power grid. The inverter controller operates by prioritizing the reactive power output by the inverter over the active power output by the inverter so that the inverter is able to generate an output that meets the reactive power command from a utility and supplies the maximum amount of active power.

Abstract: A method and an arrangement are disclosed for determining the direction of excess currents in energy supply networks, such as in medium voltage networks. An exemplary method and arrangement render it possible to reliably isolate a point of fault caused by a short-circuit or excess current, even if switching systems of the energy supply network do not include a capacitive pickup. Exemplary arrangements include an energy supply network which connects, via a transformer, a medium voltage network to a low voltage network.

Abstract: A power conversion system includes a master power conversion device and one or more slave power conversion devices. Each power conversion device includes: a time counter and a carrier wave generator for synchronization with the time counter. The master power conversion device includes: a synchronization data generating unit for synchronizing a value of the time counter of the slave power conversion device with that of the master power conversion device. The slave power conversion device further includes: a time counter correcting unit that corrects the value of the time counter on the basis of the received synchronization data; a current sensor that detects a current on an output side of the slave power conversion device; and a gate timing adjusting unit that advances or delays a phase of the gate signal of the slave power conversion device.

Abstract: Disclosed are exemplary embodiments of systems and methods for determining a power stealing capability of a climate control system controller. In an exemplary embodiment, a controller for use in a climate control system generally includes a capacitor chargeable by current flowing through an off-mode load of the climate control system. A voltage detect circuit detects a voltage across the capacitor. The controller includes a timer for determining a charge time of the capacitor from a first specific voltage to a second specific voltage based on input from the voltage detect circuit. The controller determines a resistance of the off-mode load based on the charge time and, based on the determined resistance, determines a level of current for power stealing through the off-mode load.

Abstract: Control circuitry for stabilizing a DC voltage outputted by a DC power supply against changes in ambient temperature. The control circuitry includes: measurement circuitry configured to output a measurement voltage representative of a DC voltage outputted by a DC power supply; reference circuitry configured to output a reference voltage; and comparison circuitry configured to compare the measurement voltage with the reference voltage and, based on the comparison, output a control signal for controlling the DC voltage outputted by the DC power supply. At least one temperature-sensitive component of the control circuitry is located in an enclosure configured to maintain a substantially constant temperature within the enclosure.

Abstract: Techniques are described for a multi-function pin of a light emitting diode (LED) driver. The techniques utilize this multi-function pin for switching current that flows through one or more LEDs, as well as for charging the power supply of the LED driver. The techniques further utilize this multi-function pin to determine whether the voltage at an external transistor is beginning to oscillate, and utilize this multi-function pin to determine whether the current through the one or more LEDs has fully dissipated to an amplitude of zero.

Abstract: Embodiments of the present invention provide an apparatus for optimum power tracking for distributed power sources. The apparatus includes a plurality of distributed-input parallel-output converters. Each converter is operably connected to a corresponding power source to form a power-processing channel. The apparatus also includes a controller operably connected to the plurality of converters, and is configured to provide uniform input voltages across each power source while tracking an optimum power point. The controller provides tolerance for multiple faults up to N?1 power source failures for the apparatus comprising an N-channel converter power system with N distributed power sources.

Abstract: A system may include a switchover element configurable to source or sink power from or to an electronic device electrically coupled to the switchover element and a controller in communication with the switchover element. The controller may be configured to determine if the electronic device is healthy. When the electronic device is healthy, the controller may configure the switchover element to deliver power from the electronic device to the system andconfigure the switchover element to provide the power to any unhealthy electronic device electrically coupled to the system.

Abstract: To perform an anti-windup control without interference with a cross current compensating function even in case of voltage saturation. There is provided a feedback value calculating section to calculate an average of voltage commands V1_cmd, V2_cmd after output limitation, as a feedback value. As a deviation used for an integral calculation of a current control section 6a, 6b, a sum obtained by adding a product to a deviation between a current command value Id_cmd, Iq_cmd and a current detection value Id_det, Iq_det is used. The product is a quantity obtained by multiplying a saturation quantity by a feedback gain Kfb. The saturation quantity is a saturation quantity of an operation quantity limited by a voltage command limiting section 3a, 3b, and the saturation quantity is a deviation or difference between a feedback value V_fb (Vd_fb, Vq_fb) and the voltage command Vd_cmd.

Abstract: A method of controlling a power plant connected at a point of connection to an electricity grid is provided. The power plant includes a power production facility connected to a power storage facility. The method includes determining a reactive power grid demand and/or voltage grid demand of the electricity grid, obtaining operating data for the power plant facilities, computing reactive power and/or voltage references for the power plant facilities on the basis of the grid demands and the operating data, and operating the power plant facilities on the basis of the references such that a net reactive power and/or a net voltage at the point of connection fulfills a grid demand. A plant controller for controlling a power plant is also provided. A power plant including power production facilities connected to power storage facilities, and the plant controller using the method is also provided.

Abstract: A power conversion system for providing power to an electrical grid is described. The system includes a power converter coupled to a direct current (DC) power source. The system also includes a contactor coupled to the power converter and the electrical grid and configured to selectively electrically couple the power converter to the electrical grid. The system also includes a system controller communicatively coupled to the power converter and the contactor and configured to close the contactor to electrically couple the power converter to the electrical grid and to activate the power converter when a DC voltage provided has remained higher than a voltage level for a length of time. The system controller is also configured to deactivate the power converter, while the contactor is maintained in the closed position, when an alternating current (AC) power output has remained lower than a power level for a length of time.

Abstract: A transformer and a fabricating method for transformer. The transformer includes a stand, two primary-sides, a secondary-side and multiple pins. The stand has a top-portion, a bottom-portion and a middle-portion connecting the top-portion and the bottom-portion. The primary-sides are disposed on the middle-portion and the secondary-side is disposed on the middle-portion between and insulated from the two primary-sides. The pins are plugged under the bottom-portion and electrically connected to the primary-sides and the secondary-side, wherein each of the primary-sides and secondary-side has multiple thread-ends respectively connecting one pin. The bottom-portion has multiple slots corresponding to the pins.

Abstract: A meshed HVDC power transmission network comprises at least three HVDC converter stations interconnected in a first closed path by at least three transmission lines. A first DC power flow control device is series connected to a first of the at least three transmission lines. That first DC power flow control device takes its power from the first transmission line and balances the DC current distribution in the first closed path.

Abstract: A plurality of sodium-sulfur batteries are divided into a plurality of groups. Power to be input or output, which is assigned to all sodium-sulfur batteries in order to compensate for fluctuations of output power of a power generation device, is distributed to each group. The plurality of sodium-sulfur batteries divided in the groups are periodically rotated. This enables a uniform utilization rate of the sodium-sulfur batteries to be achieved.

Abstract: [Problem] When load power is assisted, the number of component parts becomes greater because an AC power detector is provided in the AC power supply of an inverter. [Means for Solution] An instantaneous output power calculating section comprises a power calculating section to calculate power by using detected values of voltage and current on the output side of an inverter, and a correction calculating section to correct the calculated power. Moreover, limiter sections are provided, respectively, in charge control section and discharge control section for a chopper, and limiter values of the limiter sections are varied by the power calculated by the instantaneous output power calculating section.

Abstract: A seamless power transfer apparatus comprising a solar grid and a utility power grid. The apparatus comprises a smart switch electrically connected to the solar grid and to the utility grid. The smart switch does not allow the solar grid to supply power to the utility power grid at any time.

Abstract: An effective, yet relatively simple and inexpensive, method for detection of islanding in distributed power generation systems. Statistical analysis of the local line frequency, as measured at the distributed generator, is performed to detect when an island has been formed. The statistical characteristics of the local frequency are controlled by the grid when the distributed generator is not islanding. When an island is formed, however, frequency control switches to circuitry associated with the distributed generator. Because the statistical characteristics of the frequency control performed by the distributed generator are markedly different from those of the grid, the islanding condition can be detected and corrected.

Abstract: The invention related in cell parallel device is a circuit of SCR S1 to S4, comprises: a first terminal connected T1 to positive voltage terminal of first cell E1; a second terminal T2 connected to positive voltage terminal of second cell E2; and a third terminal T3 connected to voltage positive terminal of charge element CD or load LD, and trigger element TE connected between gate and anode of the SCR S1 to S4, the negative voltage terminal of charge element CD or load LD connected to negative voltage terminal of first cell E1 and second cell E2, can be not occur loop current in cells parallel circuit.

Abstract: Different types of energy storage systems are described, in particular hydro-pneumatic storage systems. In one, energy is stored by compressing gas in a chamber (44,45,54,55) with a liquid piston and released by gas expansion. A spray head or grid at the top of the chamber (44,45,54,55) supplies liquid as a shower through the gas being compressed or expanding in the cylinder (11,12) to maintain an isothermal condition. In another, energy is stored from an array of solar cells connected to an array of supercapacitors forming an auxiliary storage, and a main energy storage device such as a hydro-pneumatic storage system, for supply to an AC or DC network. The efficiency is improved by connecting the solar cells via the array of supercapacitors to the AC or DC network.

Abstract: The present invention provides a power supply control system and a semiconductor integrated circuit that may prevent reverse current flow from a solar battery to a primary battery. Namely, in a first switching circuit, a first voltage that is the primary battery output voltage dropped by a first voltage level and a second voltage that is the load side voltage dropped by a second voltage level are compared by a comparator. Electrical connection between the primary battery and the load is disconnected when the second voltage is equal to or greater than the first voltage. In a second switching circuit for a solar battery and the load, the switching circuit is similarly switched OFF before the load side voltage exceeds the output voltage of the primary battery or the solar battery, preventing damage to the battery due to reverse flow of current.

Abstract: A system, method, and apparatus for managing an application of power from photovoltaic arrays to power conversion components. The method may include arranging a first array and a second array in series, coupling a positive terminal of a first array to the power conversion component, coupling a negative terminal of a second array to the power conversion component, and modulating an amount of current flowing between a negative terminal of the first array and a positive terminal of the second array so as to ramp up a level of current flowing through the arrays as the arrays are brought online with the power conversion component. A voltage of any terminal on either of the arrays may be limited so that the voltage on any of the terminals does not reach a restricted level.

Abstract: A backup power supply device configured to supply an electric power for backup to an optical encoder 11 when a main power supply 13 for driving the optical encoder 11 breaks down, the backup power supply device comprises: a battery 12 configured to storage a DC power; a capacitor 33 configured to storage a DC power, the capacitor 33 configured to supply an electric power for backup to the optical encoder 11 when the battery 12 cannot supply the electric power thereof; a discharge device 34 configured to discharge the electric power charged in the battery 12; and a periodical discharge controller 35 configured to perform control to intermittently output the electric power charged in the battery 12 to the discharge device 34 to consume the battery power.

Abstract: An arrangement for protecting equipment of an AC electrical power system comprises first means configured to measure the frequency of the current and voltage at at least one location in the electrical power system along an interconnection between two theoretical electric machines of an equivalent two machine system. Fourth means are configured to use the values of the frequency of the current and voltage measured to determine whether a power swing has occurred and if an occurrence of a power swing has been determined determine whether the measuring location is located on a motor side or a generator side of a potential pole slip electrical centre along said interconnection, the electrical centre being defined as the location where the voltage becomes zero during a pole slip, and send this information further to third means for use in a control for protecting equipment of the electrical power system.

Abstract: A power system (110; 210; 310) combines a power source (14) having a DC output (20A, 20B) with an AC supply from the AC grid (12) to provide AC to customer's loads (16) and DC to various DC auxiliary loads (134, 134A). The DC output of the DC power source (14) is connected in steady-state to the DC input (120A, 120B, 60) of a converter/bi-directional inverter (122; 222) for conversion therein to AC for connection (124, 124A, 32) to the customer's loads (16) and (124, 124B) to any AC auxiliary loads (134, 234). During start-up of the DC power source (14), an open isolation switch (70) disconnects that DC power source (14) from the bi-directional inverter (122; 222). A start-up power supply (50, 60; 250, 60; 90, 180, 60) selectively connects (56; 94) between the AC power grid (12) and the bi-directional inverter (122; 222) and/or DC controllers (134A) to provide a supply of rectified DC power at the inverter DC input and to certain DC auxiliary loads (134, 234).

Abstract: A method and apparatus for sustained power self-generation using a reduced drag high efficiency (HE) electric machine are disclosed. Electric power supply having a power level is produced from an electrical generation unit including an HE electric machine and a non-fossil fuel unit such as a hydrogen unit, a hydro unit, a battery, a power grid and so on. Portions of the electric power supply are diverted to the electrical generation unit, another electrical generation unit including an HE electric machine and a non-fossil fuel unit, and a power distribution grid. The HE machines includes a conversion efficiency factor rating of greater than 1 hp of input power to 746 watts of output power.

Abstract: Methods, apparatus, and products for dynamically configuring current sharing and fault monitoring in redundant power supply modules for components of an electrically powered system, including summing, by a master service processor, during powered operation of the system, the present power requirements of components presently installed in the electrically powered system and setting, by the master service processor for each redundant power supply module in dependence upon the sum of the present power requirements, a current sharing tolerance and a fault reporting tolerance.

Abstract: Techniques for DC-to-AC conversion are disclosed, and may be embodied in a solar inverter device that can operatively couple to a power grid. The device includes a photovoltaic (PV) stack including series-connected PV modules. Each PV module is associated with a capacitor for storing output of that PV module. A positive terminator circuit switches a negative end of the PV stack to ground during positive half of grid cycle, and a negative terminator switches a positive end of the PV stack to ground during negative half of grid cycle. A connecting branch couples each PV module output to a common bus, each branch including control circuitry configured to selectively couple the corresponding PV module output to bus. During a first half of grid cycle, some of the capacitors discharge to the grid while a balance of the capacitors charge in preparation for discharge during a second half of grid cycle.

Abstract: A power safety system includes a first MOS, a second MOS, a switch and a body controller. The first MOS is connected between a power input and a power output. The second MOSFET is connected between the power output and a charging output. The switch has an end connected to the body of the first MOS, and the opposite end switched between the source and the drain of the first MOS. A body controller controls the switch according to the voltage at the power input and the voltage at the power output, to connect the body of the first MOS to the source or the drain of the first MOS. By switching the switch, the first MOS will have a parasitic diode effective to prevent a reverse current from the power output to the power input.

Abstract: A fan includes a motor control device which is electrically connected with a motor and an alternating current power source. The motor control device includes a converting circuit, a power factor correction circuit and a motor controlling circuit. The voltage of the alternating current power source is converted to be direct current voltage by the converting circuit and the power factor correction circuit, and then the direct current voltage is outputted to the motor control circuit. The motor controlling circuit generates a driving signal in accordance with the direct current voltage for driving the motor to operate.

Abstract: Techniques for DC-to-AC conversion are disclosed, and may be embodied in a solar inverter device that can operatively couple to a power grid. The device includes a photovoltaic (PV) stack including series-connected PV modules. Each PV module is associated with a capacitor for storing output of that PV module. A positive terminator circuit switches a negative end of the PV stack to ground during positive half of grid cycle, and a negative terminator switches a positive end of the PV stack to ground during negative half of grid cycle. A connecting branch couples each PV module output to a common bus, each branch including control circuitry configured to selectively couple the corresponding PV module output to bus. During a first half of grid cycle, some of the capacitors discharge to the grid while a balance of the capacitors charge in preparation for discharge during a second half of grid cycle.

Abstract: A circuit system layout method for laying out a circuit system has a standby power supply unit. The circuit system includes a core circuit set and a non-core circuit set and operates on power supplied by a power source. The core circuit set is still enabled to finalize a temporary process with the power supplied by the standby power supply unit upon an unexpected interruption of the power supplied by the power source. The core circuit set is connected to an energy storing element for storing and discharging the power, and connected to a one-way element for ensuring that the power stored in the energy storing element is supplied to the core circuit set only. The core circuit set performs the temporary process even when the power source does not enable the circuit system to operate. The circuit system is further provided.

Abstract: A scalable intelligent power-supply system and method capable of powering a defined load for a specified period of time is disclosed and claimed. Multiple external AC and DC inputs supply power to the system if available and required. An internal DC input from a back-up energy source is on board. The back-up energy source is scalable by adding additional energy cartridges such as batteries in racks mounted within frames of the system. The AC and DC inputs (including the internal DC input) are controlled, measured, sensed, and converted by circuitry controlled by the microprocessor into multiple AC and/or DC outputs. A microprocessor manages power input to, within, and output from the system. The performance of a Lithium-ion batteries used to power an automobile can be determined on the basis individual battery packs or individual battery cells within the packs.

Abstract: A power stealing circuit for stealing power to operate a control device is disclosed. In one illustrative embodiment, power may be periodically or intermittently diverted from a power source to a power stealing block. When power is diverted to the power stealing block, the power stealing block may steal power from the power source and store the stolen power on a storage device. The storage device may then provide operating power to a control device. In some embodiments, the power stealing block may include a first path for charging the storage device when a switch is ON, and a second path for charging the storage device when the switch is off. The switch may be switched OFF when, for example, when the voltage provided by the rectifier is greater than a threshold voltage, the voltage detected on the storage device is greater than a threshold value, and/or when a control signal from a controller disables the switch.

Abstract: Techniques for DC-to-AC conversion are disclosed, and may be embodied in a solar inverter device that can operatively couple to a power grid. The device includes a photovoltaic (PV) stack including series-connected PV modules. Each PV module is associated with a capacitor for storing output of that PV module. A positive terminator circuit switches a negative end of the PV stack to ground during positive half of grid cycle, and a negative terminator switches a positive end of the PV stack to ground during negative half of grid cycle. A connecting branch couples each PV module output to a common bus, each branch including control circuitry configured to selectively couple the corresponding PV module output to bus. During a first half of grid cycle, some of the capacitors discharge to the grid while a balance of the capacitors charge in preparation for discharge during a second half of grid cycle.

Abstract: A control apparatus for controlling a fuel pump includes: an electronic switch provided in a circuit for connecting a power supply to a motor for driving the fuel pump; a current detector which detects a current which flows through the motor; and a controller which controls the electronic switch in a first PWM mode of a first frequency and a first duty ratio in a normal operation; and change a PWM mode to control the electronic switch in a second PWM mode of a second frequency lower than the first frequency and a second duty ratio lower than the first duty ratio when the current flowing through the motor exceeds a threshold current value in the normal operation.

Abstract: A photovoltaic power generation system includes: a plurality of units, each of the units being formed with a string, which is a series-connection body of a plurality of solar cell modules, or with a solar cell module; a plurality of connection cables to which the units are each connected such that the units are parallelly connected to each other; a junction box to which each end of the plurality of connection cables is connected; and a failure detection section that performs failure detection and outputs a detection result on a unit-by-unit basis, the failure detection section being located outside the junction box.