Abstract: A ground-fault detecting device includes: a first detecting module, having a first input terminal, a second input terminal, and a third input terminal coupled to a first-phase electric power, a second-phase electric power, and a third-phase electric power on an AC side of a photovoltaic power generating system respectively, for sampling voltages of the first-phase electric power, the second-phase electric power, and the third-phase electric power to generate a first sampled voltage, a second sampled voltage, and a third sampled voltage respectively; and a controller, coupled to the first detecting module, for determining if a ground-fault occurs in the AC side before the photovoltaic power generating system is connected to a grid according to the first sampled voltage, the second sampled voltage, and the third sampled voltage; wherein the controller generates an alarm signal when the ground-fault occurs in the AC side.

Abstract: An extension cord for polyphase voltage conversion includes a socket body, a conductive cable and a polyphase circuit disposed in the socket body. The socket body has a hollow housing, and a four-phase power connective head is disposed at an end of the housing in order to supply power to the extension cord. A breaker having safety switch function and at least two power sockets providing voltages with different phases are disposed in the housing. An end of the conductive cable is electrically connectable with a four-phase power source. The other end of the conductive cable has a four-phase power plug electrically connectable with the four-phase power connective head of the socket body. The polyphase circuit includes three phase conductors, a neutral conductor and a ground conductor. The conductors are used to electrically connect with the four-phase power connective head, the breaker and the respective at least two power sockets.

Abstract: Some embodiments include a high voltage direct current (HVDC) power generator system for information technology (IT) racks. The HVDC power generator system can include a three-phase alternating current (AC) transformer having a primary winding and a plurality of secondary windings. A plurality of three-phase bridge rectifier circuits can be electrically coupled respectively to the plurality of secondary windings. The HVDC power generator system can include output terminals for powering its load. A first string of bridge rectifier circuits can be in series with each other and a first inductor. A second string of bridge rectifier circuits can be in series with each other and a second inductor. The first and second strings can be electrically coupled in parallel to the output terminals.

Abstract: A power system for multi-input devices with shared reserve power includes a first automatic transfer switch (ATS) and a second ATS each coupled at respective inputs to a primary power system and a reserve power system. An output of one of the ATSs is coupled to first power input of a multi-input electrical device and an output of the other ATS is coupled to a second power input of the multi-input electrical device. When primary power is available, electrical power is fed to both the inputs of the multi-input electrical device and when primary power is not available reserve power is fed to both inputs of the multi-input electrical device. If a component fails between the primary and/or reserve power system and the multi-input electrical device, a full load of the multi-input electrical device is fed from a non-affected one of the inputs of the multi-input electrical device.

Abstract: A circuit arrangement (10) for controlling a stator winding (11) of a stator (12) of an electric machine (13) is provided. The stator winding (11) has at least four electrical phases (?), which are designed to be supplied with a separate phase current (In), respectively. A modulation signal (M) is assigned to each electrical phase (?) and the modulation signals (M) are out of phase with respect to one another so that the stator winding (11) is designed to generate a rotary field. At least two carrier signals (T) are provided for generating the phase currents (In), and the electrical phases (?) are divided into at least two groups, each of which is assigned a carrier signal (T). The carrier signals (T) have a phase shift (?) relative to one another. Furthermore, an electric machine (13) comprising a circuit arrangement (10) is provided.

Abstract: An information processing system includes a plurality of servers stored in a first rack; and a management server coupled to the plurality of servers and configured to: acquire consumed power values from the plurality of servers when power is supplied to the plurality of servers via first power supply lines coupled to a first power strip of the first rack, calculate the total of the consumed power values based on the values of power consumed by the plurality of servers, and switch a power supply of at least one servers among the plurality of servers so that power is supplied to the at least one server via a second power supply line coupled to a second power strip of a second rack when the total of the consumed power values exceeds a first threshold.

Abstract: A modular uninterruptible power supply (UPS) provides modular uninterruptible power support to multiple rack computer systems. The modular UPS can include one or more rectifier, battery, and inverter modules installed in one or more rack frames. The modules can be installed in a common rack frame and electrically coupled via a bus bar coupled to the frame. The modules can be installed in separate rack frames and electrically coupled via a bus bar extending between the separate rack frames. The modular UPS can include multiple sets of rectifier modules and battery modules which are electrically coupled to the rack computer systems in parallel and can provide uninterruptible power support subsequent to at least one module failure. The rectifier, battery, and inverter modules installed in the rack frames can be adjusted to provide scalable power support based at least in part upon the power support requirements of the rack computer systems.

Abstract: The present disclosure is directed to a method for generating power for a machine. The method may include inverting a common power at a first location and outputting a first inverted power. The method may further include inverting the common power at a second location, outputting a second inverted power, and shifting an operational phase of the second inverted power so that the first inverted power and the second inverted power are in phase. The method may further include passing the first inverted power to a transformer, passing the second inverted power to the transformer, and transforming the first inverted power and the second inverted power to a transformed power.

Abstract: In a lighting device, each of n circuit blocks includes a current controller, a storage element, a charging current controller, a charging rectifier element, and a discharging rectifier element. A first circuit block of the n circuit blocks is configured such that a pulsating voltage generated by rectifying a sine wave AC voltage is applied to the series circuit of the current controller and one light source electrically connected to the first circuit block. An i-th circuit block of the n circuit blocks is electrically connected in parallel to the current controller of an i-1-th circuit block via an i-1-th connection rectifier element.

Abstract: A power routing rack can be used to provide various power support redundancies to one or more computing racks in a data center. Power feeds are supplied to bus bars in a power bus bar array extending through the rack, and power routing assemblies positioned in the rack route power from one or more of the bus bars to a computing rack. Each assembly includes circuit breakers that couple to separate bus bars and a routing module that routes power from one or more of the circuit breakers to one or more computing racks. The routing module can include a transfer switch that selectively routes power. The routing module can include an electrical bridge that concurrently routes power. Each assembly can be positioned within the rack to couple the circuit breakers to various power bus bars to adjust the power support redundancy provided to one or more computing racks.

Abstract: Systems and methods for data center power supply control are provided that identify a parameter of at least one of a plurality of servers that form at least part of a data center that includes an uninterruptable power supply. An estimated parameter of a virtual server can be identified, and one of the plurality of servers can be selected based at least in part on the parameter and the estimated parameter. The virtual server can be provided to the selected server, and the power provided to at least one of the plurality of servers can be reduced, shut down, or otherwise adjusted.

Abstract: A method for protecting batteries with consideration for the influence of a load coupled to a battery pack is provided. The battery pack includes a terminal to be coupled to a capacitor of the load, and a battery management system for controlling a protection operation according to a voltage of the terminal, counting a number of protection operation executions after the load is coupled to the battery pack, and differently controlling a deactivation time of the protection operations depending on whether or not the number of executions is greater than or equal to a reference count.

Abstract: Provided are an apparatus and method for load-balancing of a three-phase electric power distribution system having a multi-phase feeder, including obtaining topology information of the feeder identifying supply points for customer loads and feeder sections between the supply points, obtaining customer information that includes peak customer load at each of the points between each of the feeder sections, performing a phase balancing analysis, and recommending phase assignment at the customer load supply points.

Abstract: A phase balancing system includes a load forecasting module, a phase unbalance identification module and a demand response module. The load forecasting module determines a load forecast for the distribution system for the period of interest and the phase unbalance identification module determines voltage unbalance on the distribution system for the period of interest. The demand response module estimates an available demand response on the distribution system for the period of interest and allocates an optimized demand response from the available demand response to minimize the voltage unbalance on the distribution system for the period of interest.

Abstract: A method for providing dynamic load sharing between a first and a second three phase system is disclosed, wherein the first and second three phase system are connected to a first and second three phase interleaved winding in a generator. The method comprises determining a first q-axis control signal for the first three phase system and a second q-axis control signal for the second three phase system based on a torque and/or power demand for the generator, determining a first d-axis control signal for the first three phase system and a second d-axis control signal for the second three phase system based on a coupling effect between the first and second three phase systems, and adjusting the q-axis control signals and d-axis control signals by including at least one feed forward compensation signal, wherein said at least one feed forward compensation signal is based on a coupling effect between the first and second three phase systems.

Abstract: Phase balancing techniques for power transmission systems are disclosed. In one embodiment, a phase balancing protocol (240) includes executing a first phase balancing protocol (350) in relation to a first power transmission section (400a). A second phase balancing protocol (370) may be executed if the first phase balancing protocol (350) is unable to provide a phase balanced condition. The first phase balancing protocol (350) may utilize a first ordering sequence (364) to rank the current flow on the power lines (16) of the first power transmission section (400a), while the second phase balancing protocol (370) may utilize a second ordering sequence (384) to rank the current flow on the power lines (16) of the first power transmission section (400a). The order sequences (364, 384) are opposite of each other—one ranks the current flows from high-to-low, and the other ranks the current flow from low-to-high.

Abstract: Phase balancing techniques for power transmission systems are disclosed. In one embodiment, a phase balancing protocol (240) includes executing a first phase balancing protocol (350) in relation to a first power transmission section (400a). A second phase balancing protocol (370) may be executed if the first phase balancing protocol (350) is unable to provide a phase balanced condition. The first phase balancing protocol (350) may utilize a first ordering sequence (364) to rank the current flow on the power lines (16) of the first power transmission section (400a), while the second phase balancing protocol (370) may utilize a second ordering sequence (384) to rank the current flow on the power lines (16) of the first power transmission section (400a). The order sequences (364, 384) are opposite of each other—one ranks the current flows from high-to-low, and the other ranks the current flow from low-to-high.

Abstract: Provided are an apparatus and method for load-balancing of a three-phase electric power distribution system having a multi-phase feeder, including obtaining topology information of the feeder identifying supply points for customer loads and feeder sections between the supply points, obtaining customer information that includes peak customer load at each of the points between each of the feeder sections, performing a phase balancing analysis, and recommending phase assignment at the customer load supply points.

Abstract: An arrangement to control an electrical property of a medium or high voltage AC system including a number n of phases with n being at least two includes a number n of phases, each phase including a series connection of at least two electrical elements with an intermediate connection point between each pair of the at least two electrical elements, where each of the n phases of the arrangement is connected on one side to an original common neutral point and on the other side to one of the n phases of the AC system. The arrangement further includes a number of first switchable interconnections, where the first switchable interconnections are each arranged between two intermediate connection points of two of the n phases of the arrangement, and at least one control unit arranged to control the first switchable interconnections.

Abstract: A mobile container may include a bottom element, a top element, a front element, a back element, and two side elements defining a containment volume. The two side elements may have a length longer than a length of either the front element or the back element. The containment volume may be configured to include a plurality of rack frames. Each rack frame may include a module insertion area on a first side of the rack frame, a universal backplane area, and a power bus. The universal backplane area may be positioned on a second side of the rack frame opposite to the first side and may include at least one mounting surface configured to mount two or more backplane boards. At least two of the backplane boards may be configured to couple to two respective modules that each have at least two different functions and are insertable through the module insertion area. The at least two different functions of at least one backplane board may include rack power and management functions.

Abstract: Disclosed is a power distribution module that is capable of providing power to rack mounted equipment modules in electronic equipment mounting racks. The power distribution module may comprise a series of individual modules that can be placed at strategic locations through the electronic equipment mounting rack to meet the specific power requirements of the rack mounted equipment modules, which may vary depending upon the type of module. In this manner, the expense of supplying power of a particular amount to a specific location can be reduced. In addition, power distribution modules are disclosed that are prefabricated in different versions to meet the power requirements of the design of the electronic equipment mounting rack.

Abstract: The Universal Power Inlet System, or UPIS, is a method of providing universal attachment of 3 different types of electrical power systems into the input circuitry of a Power Distribution Unit, or PDU. This method allows use of either fixed or detachable power cord options permitting the PDU to be powered by any of the following types of electrical power sources: 3-Phase Delta, 3-Phase Star (or Wye) and Single-Phase. This method also describes a way to uniquely identify the specific power system the mentioned PDU is currently attached to. The method also optionally allows derivation of supplementary information about the electrical power system such as current capacity, or ampacity, of the power cord being used. All this information can be used for capacity monitoring and reporting as well as protection of PDU circuitry and power cords.

Abstract: A switching power supply circuit includes a plurality of switching regulators and a timing adjustment circuit. The plurality of switching regulators converts an input voltage input to an input terminal into a plurality of predetermined constant voltages, and outputs the plurality of predetermined constant voltages from a plurality of output terminals, respectively. The timing adjustment circuit adjusts phases of a plurality of pulse signals generated by the plurality of switching regulators so that the phases of the plurality of pulse signals are different from each other, and outputs the plurality of adjusted pulse signals to respective switch circuits of the plurality of switching regulators.

Abstract: A controller box comprises an array of switches for arbitrarily connecting loads to any selected power phase of a polyphase supply circuit. By evenly balancing the loads amongst the phases the efficiency of the total power delivered is thereby improved.

Abstract: An apparatus for reducing a neutral current using a load switching method in accordance with the present invention includes a phase current detection unit for detecting a phase current in each of a top stage power line and a bottom stage power line, a load switching unit for changing an arrangement of a load connected each phase of at least one among the top stage power line and the bottom stage power line and a control unit for controlling the load switching unit so as to compare a strength of the detected phase current of the top stage power line with a strength of the detected phase current of the bottom stage power line and to change the arrangement of the load connected to each phase of at least one among the top stage power line and the bottom stage power line according to the comparison result.

Abstract: Current sharing scheme based on input power and/or the power efficiency for a power stage with multiple phases and/or paralleled modules is described. According to the scheme, duty cycles of different phases/modules may be adaptively adjusted until the minimum input power and/or the maximum power efficiency is achieved. For certain input voltages, the minimum input power exists at the minimum total input current. Thus, input power and/or the input current may be used as an indicator of the maximized power efficiency of the power stage and hence be used to track the optimal current sharing ratio among the multiple phases/modules.

Abstract: A system comprises a first equipment rack, a power distribution unit (PDU) and a plurality of rack connectors. The PDU is mounted in the first equipment rack and is configured to provide alternating current (AC) power that comprises a plurality of phases. The plurality of rack connectors mount within the first equipment rack, and each of the plurality of rack connectors couples to the PDU and provides access to the plurality of phases. Each rack connector is usable to accommodate a first device installed in the equipment rack that uses one or more of the plurality of phases, and is also usable to accommodate a second device installed in the equipment rack that uses one or more of the plurality of phases, thereby permitting each rack connector to couple to any of a plurality of devices, and permitting each of the plurality of devices to use any number of the plurality of phases. The number of phases used by the first device differs from the number of phases used by the second device.

Abstract: A converter for a multi-phase current network can include a plurality of current sensors, each of the plurality of current sensors being configured to detect current for a respective phase of the multi-phase network. A current averaging circuit is configured to provide an indication of the average current for the multi-phase network based on the current detected by each of the plurality of current sensors. A modulator is configured to modulate at least one phase of the multi-phase network independently of each other phase of the multi-phase network based on a difference between the current detected for the at least one phase and the average current for the multi-phase network.

Abstract: Provided is an apparatus and method for providing to a differential relay an operational vector-group compensation setting pair that automatically provides correction for a phase shift occurring between currents of at least two windings of a power transformer. The method includes calculating a first and second plurality of phasors using secondary currents derived from respective first and second winding of the at least two windings. The method also includes selecting one pair of vector-group compensation settings based on operate current values calculated using different pair combinations of the vector-group compensation settings applied to the first and second plurality of phasors.

Abstract: An uninterruptible power supply (UPS) system includes an AC power input configured to receive AC power from a single-phase AC power source or a multi-phase AC power source, a DC power source, an output circuit including a power output, a controllable switch configured to selectively couple at least one of the AC power input and the DC power source to the output circuit, and a processor coupled and configured to affect operation of the output circuit depending upon which of single-phase and multi-phase operation of the UPS is indicated.

Abstract: A control system for canceling load unbalance of a three-phase circuit includes phase current detectors for detecting phase currents caused to flow through a secondary circuit of a current transformer provided in high voltage distribution lines, respectively, phase change-over switches through which phases of the high voltage distribution lines, and primary sides of distribution transformers provided across high and low voltage distribution lines are connected to each other, a control center for, when a magnitude of a zero-phase current detected by the zero-phase current detector is larger than a predetermined value, on the basis of the phase currents, respectively, out putting a control signal so that the load of the phase having a maximum current appearing therein is changed over to the phase having a minimum current recognized therein, and a phase change-over slave station for controlling the phase change-over for the phase change-over switches in accordance with the control signal.

Abstract: It is an object of the present invention to prevent temperature decrease in a border portion of each of heating coils and to enable to eliminate an influence given by the change in a load state. In order to attain this object, an induction heating unit according to the present invention is provided with control units respectively corresponding to a plurality of heating units. A phase detector of the control unit obtains a phase difference between an output current (heating coil current) of an inverter detected by a current transformer reference signal outputted by a reference signal generating section, and inputs it to a drive control section. The drive control section adjusts an output timing (phase) of a gate pulse to be given to the inverter so as to make a phase of the heating coil current of the inverter coincide with a phase of the reference signal outputted by the reference signal generating section.

Abstract: A harmonic mitigating device also functions as a phase converter for supplying single-phase non-linear loads, or as a phase shifting device for three-phase non-linear loads with multiple inputs to create a quasi multi-pulse system. A multiple-winding reactor or a plurality of single-winding reactors, and at least one capacitor, are connected in a crosslink circuit between the reactor windings, or between the reactor windings and another line. At least one reactive element comprising a line winding is connected to each phase or to the neutral and in series with a non-linear load, which provides a high reactance to harmonic currents, and at least one crosslink circuit comprising a second reactive element connected between the second end of the line winding and a capacitor which is connected to any other line in the system.

Abstract: The invention is an apparatus and a method for connecting loads to a polyphase power distribution system in such a way that the loads on the individual phases of the system are balanced. The apparatus includes an equipment rack having multiple electrical equipment mounting positions and multiple electrical outlets wherein contiguous groups of mounting positions are adjacent to groups of outlets connected to different phases. The apparatus also provides for other groups of outlets adjacent to the mounting positions to be connected to different power sources for increased reliability when the equipment has redundant power supplies.

Abstract: A coupling circuit (30) connects two three-phase pulse width modulated (PWM) inverter circuits (16, 18), used in conventional manner to power a first load (12), in order to independently power a second load (32). In a preferred embodiment, the two PWM inverter circuits propel an armored vehicle, such as a tank, with one motor driving the right side, and the other motor driving the left side. The propulsion of the vehicle represents the first load. The second load is a pulse forming network (PFN), which PFN powers an electrothermal gun system carried by the vehicle. The coupling circuit includes a transformer (TA, TB, TC) and rectifier circuit (34) for each phase output of the PWM inverters. A primary winding (32) of each transformer is connected between corresponding phase outputs of the two PWM inverters. A secondary winding of each transformer is connected to a respective rectifier circuit. The output of each rectifier circuit is joined with the other rectifier outputs to charge the PFN.

Abstract: A ferroresonant three-phase constant AC voltage transformer comprising three transformer iron cores with one for each corresponding input supply phase, primary windings and secondary windings formed on each of the transformer iron cores, series reactance components or reactors connected in series, with the primary windings, automatic voltage regulating means for controlling secondary output voltages generated at the secondary windings to a predetermined target value, compensating windings formed so as to be inductively coupled to each of the series reactance components or reactors, and means for connecting the compensating windings in series with each other to form a closed loop circuit. The secondary output voltages are theoretically kept in balanced condition even when the loads or the primary input voltages or both are unbalanced.

Abstract: A current balancer for balancing one or more currents provided from a three-phase source to a load includes three current transformer/full-wave rectifier bridge sections and one or more saturable core reactors. Each of the current transformer/full-wave rectifier bridge sections is to be connected to a respective one of the phase lines, and a saturable core reactor is to be connected into each phase line whose current is to be controlled. The outputs of all three current transformer/full-wave rectifier bridge sections are connected in electrical parallel to provide a single direct current control current to the saturable core reactor(s).

Abstract: An earthed circuit for an electric railway car which is equipped with an electric circuit including an electrical apparatus for which a switching operation is performed by use of a power semiconductor device includes a first brush attached to one of the axles of the car for connecting a return circuit for the electric circuit to the ground and a second brush attached to the same axle to which the first brush is attached for connecting the car body and a box for holding the electrical apparatus to the ground. The noise current caused by the switching operation of the power semiconductor device can be effectively prevented from flowing into the rails on which the car is running.

Abstract: An apparatus for controlling electrical characteristics in an alternating current system includes a first level of magnetic amplifiers which are responsive to a primary direct current control signal. The magnetic amplifiers provide secondary control signals in response to the primary control signal. The secondary control signals control a second level which includes a magnetic amplifier having gate windings to which the alternating current to be controlled is connected. Depending upon the nature of the primary control signal, the current magnitude or voltage magnitude of the alternating current can be controlled, both in relation to other alternating currents and in relation to a predetermined current or voltage magnitude.

Abstract: An apparatus which automatically balances the magnitudes of each phase current in a multi-phase power system includes electrical conductors, or phase lines, variable reactance evices, and control elements. Each phase line connects to a variable reactance device which can change the reactance of the line to thereby control the magnitude of the phase current. The variation of the reactance in one line is controlled by a control element which supplies the reactance device with a direct current converted from the alternating current of another phase line. This direct current generates a magnetic field which saturates the reactance device and thereby balances the controlled phase's current by interacting with the magnetic fields generated in the reactance device by that phase's alternating current. Total balancing is obtained by concatenating the control elements to reactance devices of all phases, i.e., one phase controls a second phase, the second controls a third, . . ., the n.sup.th -1 controls the n.sup.