Abstract: A device which can dynamically configure an array of power supply cells such as photovoltaic (PV) solar cells to provide power to a load device based on the power requirements of the load device. By selectively configuring the array of power supply cells according to one of a number of available series/parallel connection schemes, the supplied power can be more closely tailored by a controller to the requirements of the load device.

Abstract: Disclosed herein is a power supply device including: a position detection signal output section configured to output a position detection signal to a line allowing a current flow in only one direction in response to an order to output the position detection signal from a power supply managing device connected to a bus line including the line; a position detection signal detector configured to detect the position detection signal that is output from another device and flows through the line; and a position detection signal responder configured to respond that the position detection signal is detected to the power supply managing device when the position detection signal is detected by the position detection signal detector.

Abstract: Apparatuses and methods include a solar array having one or more strings of series-connected local management units (LMUs). Each LMU is parallel-connected to one of a plurality of solar modules. The strings are connected in parallel via a parallel bus. Local string management units (LSMUs) can increase or decrease an output voltage of the solar array by upconverting or downconverting string output voltages from each string. LSMUs can also operate in a bypass mode to increase overall power output.

Abstract: DC-DC converters are described that employ a time-averaged modulated bypass diode to facilitate the efficient harvest of power in photovoltaic systems.

Abstract: Techniques for providing multiple power supplies in electronic devices are disclosed. According to one aspect of the present invention, an appropriate power supply is provided only to accommodate a volume setting. In other words, there are at least two power supplies, one with a low voltage and the other with a high voltage. The high voltage power supply is only applied when there is a need to accommodate a volume setting. Thus the power consumption of the amplifiers is well controlled. As a result, the designs of the device and heat dissipation therein can be simplified and lowered in cost.

Abstract: A fuel cell stack includes a plurality of unit cells, bypass resistors, and connective resistors. The unit cells are connected in series and/or in parallel. The connected resistors are disposed between the unit cells connected in series and disconnected by heat due to resistance at a small current value in comparison to an current collector. The bypass resistors are connected in parallel to the unit cells or the unit cells connected in parallel.

Abstract: An electronic power supply circuit for battery-powered hardware devices is disclosed which can be electronically switched to supply any of at least two predetermined voltages wherein the batteries are switched in parallel or in series depending on the desired voltage. Also disclosed is an electronic apparatus comprising the electronic power supply circuit, which in some modes of operation uses the highest of the two predetermined voltages and which in other modes of operation can function with the lower of two predetermined voltages, and includes control logic that switches the electronic power supply circuit to supply said higher voltage when the apparatus in a mode in which it uses this higher voltage and that switches said electronic power supply circuit to supply said lower voltage at least during some of the modes in which the apparatus can function with the lower voltage.

Abstract: A marine power system comprises a motor for providing propulsion. It also comprises an energy storage unit (ESU) for storing and supplying energy to the motor. A prime power system is connected to the ESU and motor for selectively providing energy to these subsystems through a bus. The motor selectively receives energy from the prime power system and the ESU and can supply regenerative braking energy to the bus. The system can also accommodate multiple generator sets providing system power. The ESU can also provide starting power for the prime power system. Alternately, the prime power system drives a mechanical power system output shaft connected to the motor, and the marine system comprises an alternator driven by the prime power system output shaft. The ESU can transmit energy to the alternator. The prime power system can be located on a tugboat displacing a barge carrying the energy storage unit.

Abstract: An electronically reconfigurable battery includes a number of battery modules selectively interconnected by a number of electronic switches, wherein a selectable number of battery modules may be connected either in a series configuration or in a parallel configuration, as a result of placing selected switches of said plurality of switches in open states or closed states. In a parallel configuration, the battery provides power to a primary load, such as a propulsion load for a vehicle. In a series configuration, the battery is configured to provide a high voltage and high power output to a short-term and/or pulsed load, such as an additional load provided on the vehicle.

Abstract: In a photovoltaic system including a plurality of strings, each includes a plurality of photovoltaic modules exclusively connected in series, bus lines to which the strings are connected in parallel, and a converter for feeding electric energy from the bus lines into a power grid. A system voltage drop between the bus lines can be adjusted by a controller of the converter, and a current sensor is provided for each string that at least determines whether a reverse current flows to the string and reports to the controller of the converter whether a reverse current flows to the string, and the controller of the converter reduces the system voltage present between the bus lines to stop the reverse current.

Abstract: An alternating current conversion method and system are disclosed that can adapt to varying voltages of the direct current sources. An exemplary system includes a first and second connection arrangements for the voltage sources such that the direct current can be supplied to the DC/AC converter selectively in the first connection arrangement or the second connection arrangement. The selection between the first and second connection arrangements is made on the basis of the voltage levels of the voltage sources such that a proper voltage is supplied to the DC/AC converter. The numbers of the voltage sources in the connection arrangements are selected such that the first and second connection arrangements have different numbers of the voltage sources connected in series, the voltage sources being also grouped in parallel groups.

Abstract: The invention concerns a PV system in which a multitude of PV modules are interconnected to PV generators. Each of the PV modules comprises a network interface for transmitting module-specific data to a control device and analyzing the same. The data network is designed as a self-organizing network, in particular as a self-organizing meshed radio network.

Abstract: A series-parallel switching system includes two or more electric power supply sources; two or more first switches; and two or more second switches, wherein pairs of two or more first switches and two or more second switches are each independently switched, the two or more electric power supply sources are connected to a bus line that includes at least a first bus line and a second bus line, and by switching over the first switches and the second switches using the switch switching portion, the first switches and the second switches are connected to the first bus line and the second bus line or are separated from the first bus line and the second bus line, and the connection of the electric power supply device is changed over to series and parallel.

Abstract: A transmission for a motor vehicle is provided. The transmission is a plurality of switches that reeonfigurably interconnects constrained energy sources through switch settings. In one embodiment, the energy sources are batteries or fuel cells for an electric or hybrid motor vehicle. The transmission is in communication with a controller that receives energy from the plurality of energy sources and regulates output energy. In one embodiment the controller is a pulse width modulation controller and may also be an inverter and/or converter. A device for converting the output energy of the controller into one of a force or a rate is provided. In one embodiment the device is an electric motor.

Abstract: A structural module (11) for the high-concentration single-reflection photovoltaic generation, comprising a plurality of devices concentration of solar radiation (RS), which include relative parabolic reflectors (13) mounted on a base support (15), placed within the module (11), a transparent front surface (14), through which is the solar radiation (RS) is transmitted, and a plurality of photovoltaic receivers (16), mounted within the module (11) and series-connected each other, wherein the photovoltaic receivers (16) are fixed on elongated elements (10, 12), made of conductive material and suitable to dissipate heat, which accommodate a photovoltaic cell (CS) and are placed outside or inside the structural module (11).

Abstract: A battery control circuit includes an electronic switch, first and second diodes, and first and second batteries. A positive terminal of the first battery is connected to a positive terminal of the second battery through the first diode. A negative terminal of the first battery is connected to a positive terminal of the second battery through the electronic switch, and connected to a negative terminal of the second battery through the second diode. When the electronic switch receives a first control signal, the electronic switch is turned on, the first and second diodes are turned off, and the first and second batteries are connected in series. When the electronic switch receives a second control signal, the electronic switch is turned off, the first and second diodes are turned on, and the first and second batteries are connected in parallel.

Abstract: A contact array arrangement which both receives charging current for charging batteries of a battery pack, and which also breaks the parallel charging contact position (contact configuration in which individual batteries of the battery pack are charged in parallel) then reestablishes series connection of the batteries when a charge electrode array is urged against the contact array arrangement and when the charge electrode array is removed. A cover covering the contact array may be connected by throughbolts to a support supporting series connection contacts such that depressing the cover by imposing a downward force (e.g., the weight of a charge electrode array), moves the series connection contacts out of contact with those contacts receiving charge current. Springs return the series connection contacts to the series condition. Charge conductors fixed to the contact array pass through or by the series connection such that a very compact device results.

Abstract: An exemplary power source system includes a power source, controller, and a voltage fine adjusting unit. The power source includes a number of cells and a number of switches configured for connecting the cells in series or in parallel. The controller is configured for coarsely controlling an output of the power source by selectively turning on and off the switches. The voltage fine adjusting unit is configured for further and finely adjusting the output of the power source on condition that the coarsely controlled output of the power source is outside a predetermined acceptable range of output.

Abstract: The efficiency of a PV power generation system (10) is maximised by an apparatus providing series of electronic units (20) connected to the PV modules (12) and comprising microprocessor controlled DC converters/power supply units. A managing unit (60) communicates with the electronic units (20) of a string (11) in order to carry out a synergic optimization of the efficiency both of the single PV modules (12) and of the entire string (11). The apparatus also provides PV module (12) by PV module (12) diagnostic features and it is able to communicate with external devices for a full system control.

Abstract: The invention relates to a photovoltaic device comprising at least one photovoltaic cell (60) provided with active thin layers (15) deposited on a substrate (10), said active layers being unsegmented, and at least one static converter (50) associated with each photovoltaic cell (60). Each photovoltaic cell (60) supplies an electrical power with a maximum current (Icc) and a nominal voltage (Vp), and each static converter (50) is adapted in such a way as to transmit the electrical power supplied by the photovoltaic cell towards a load (100), reducing the transmitted current and increasing the transmitted voltage. The laser segmentations of the photovoltaic cells are thus limited, or completely eliminated, on a same panel. The yield of the photovoltaic device production is thereby improved and the dead surfaces are limited.

Abstract: A battery system includes batteries; a voltage detector linking batteries and detecting batteries' voltage; an equalizer linking batteries and fine-tuning their charging/discharging efficiency; a battery protection board on which there is a MCU used to receive signals from the voltage detector for characteristic differences between batteries balanced by the equalizer and batteries with similar charging and discharging efficiency; a digital interface connected between the MCU and an upper-level control system as one interface of signal transmission.

Abstract: A method of detecting a parallel source condition includes calculating a reactive power, comparing the reactive power to a predetermined threshold, and determining a parallel source condition in response to the reactive power exceeding the predetermined threshold.

Abstract: A system for maximizing power output from a photovoltaic array includes a configurable photovoltaic panel having a series-parallel selector and a bypass selector electrically controlled by a node controller. Some embodiments further include a plurality of configurable photovoltaic modules. A configurable photovoltaic panel may selectively be electrically connected to other configurable photovoltaic panels in a series circuit, a parallel circuit, or a combination of series and parallel circuits according to switching states set by the node controller for the bypass selector and series-parallel selector. A number of configurable photovoltaic panels connected in series and a number connected in parallel may optionally be selected in response to a change in an output voltage from a photovoltaic array, for example a voltage change resulting from a change in illumination, thereby causing the output voltage from the photovoltaic array to be greater than or equal to a minimum input voltage for an inverter.

Abstract: A power supply system includes an inverter circuit, for example, an inverter circuit of an uninterruptible power supply (UPS), having an output configured to be coupled to a load and an input configured to be coupled to a power source and a storage network configuration circuit configured to vary interconnections of a plurality of energy storage units of the power source, for example, plural ultracapacitors, responsive to a control input. The network configuration circuit may be operative to detect a state of the power source, such as a voltage produced thereby, and to modify parallel and serial coupling of the energy storage units responsive to the detected state. In some embodiments, the network configuration circuit may be operative to increase and/or decrease a number of the power source units connected in series across the input of the inverter circuit responsive to the detected state.

Abstract: A battery control apparatus comprising a battery circuit in which a plurality of batteries are connected to each other; a plurality of first switches that switch whether the batteries are connected in series or connected in parallel; a voltage detecting section that detects a maximum voltage output by the battery circuit; and a switch control section that, when the maximum voltage of the battery circuit occurring when the batteries are connected in parallel is less than or equal to a first threshold value, controls the first switches to connect at least a portion of the batteries in series.

Abstract: A photovoltaic system includes a first and a second photovoltaic generator (9, 11) which delivers electric energy, an inverter (4) which can be coupled to the PV-generators (9, 11) for converting electric energy of the PV generators (9, 11) to output AC energy, and a switchable coupling arrangement (3) for coupling the PV generators (9, 11) to each other and to the inverter (4). The coupling arrangement (3) is arranged functionally between the PV generators (9, 11) and the inverter (4) and designed to connect the PV generators selectively either in a series circuit arrangement or a parallel circuit arrangement to the inverter (4). The PV system (1) can therefore expediently be operated with an intermediate circuit voltage which is higher than the maximum voltage of one PV generator for achieving improved efficiency whereas it can be switched to a lower intermediate circuit voltage when necessary, for example, in case of a ground connection fault, to maintain predetermined voltage limits.

Abstract: Methods for compensating for reduced power output in stages of electrical power may be implemented within a direct current to pulse amplitude modulated (“PAM”) current converter, denominated a “PAMCC”, is connected to an individual source of direct current. The PAMCC receives direct current and provides pulse amplitude modulated current at its output. An array of PAMCCs constructed in accordance with the present invention form a distributed multiphase inverter whose combined output is the demodulated sum of the current pulse amplitude modulated by each PAMCC. The array is configured as a series of stages, wherein the power sources within each stage are in parallel. In some embodiments two or more stages are connected in series. In some embodiments tow or more stages are connected in a “Y” configuration. In some embodiments a weak power source is compensated for by adjusting the voltage or the current of the weak power source.

Abstract: An electronically reconfigurable battery includes a number of battery modules selectively interconnected by a number of electronic switches, wherein a selectable number of battery modules may be connected either in a series configuration or in a parallel configuration, as a result of placing selected switches of said plurality of switches in open states or closed states. In a parallel configuration, the battery provides power to a primary load, such as a propulsion load for a vehicle. In a series configuration, the battery is configured to provide a high voltage and high power output to a short-term and/or pulsed load, such as an additional load provided on the vehicle.

Abstract: A converter station for connecting an AC system to a bipolar HVDC transmission line. A DC neutral arrangement includes first DC breakers enabling breaking of a first current path from the neutral bus of one pole to the neutral bus of the other pole at bipolar operation of the station for changing to monopolar operation thereof for isolation of a faulty section of the system while establishing a current path to electrode line connecting members for diverting the current from the one pole thereto. A separate connecting member is provided for each of the electrode lines. A connector is configured to connect each neutral bus to an optional of the two electrode line connecting members.

Abstract: A light concentrating photovoltaic system and method is provided to address potential degradation in performance of optical concentrator and PV cell assemblies, whether due to misalignments of various components within the optical concentrator (such as light guides, focusing elements and the like), misalignment between the optical concentrator and the PV cell, or other anomalies or defects within any such component. Within a single apparatus, a number of optical concentrators and corresponding sunlight receiver assemblies (including the PV cell) are provided each with a corresponding integrated power efficiency optimizer to adjust the output voltage and current of the PV cell resulting from differing efficiencies between each one of the concentrator-receiver assemblies.

Abstract: A power supply system (SYS) and a photovoltaic device (PVE) intended therefor and comprising a plurality of DC voltage-generating photovoltaic modules (PVM) are proposed, wherein the photovoltaic modules (PVM) for generating a DC voltage (Udc*) exceeding the withstand voltage or dialectric strength (Umodmax) of the photovoltaic modules (PVM) and suitable for the high-voltage DC transmission are connected in parallel or in series to one another, wherein the power supply system (SYS) comprises a converter substation (UFS) that can be connected to a power supply network (SVN) installed for users, and includes a high-voltage DC transmission power line (HGUE) so as to transmit in the high voltage range the DC voltage (Udc*) generated by the photovoltaic device (PVE) to the converter substation (UFS).

Abstract: A street-lighting and solar energy collection system is disclosed. The system comprises a plurality of lighting/solar energy collecting units, an AC and DC power transmission means and a control unit. The system operates in one of the two operation modes. In the first operation mode as the street-lighting system, the units receive AC power from the power grid for lighting. In the second operation mode as the solar energy collecting system, the units transmit generated DC electricity to a centralized DC to AC converter in the control unit. The control unit further provides a means for switching the system in between two modes. When the system is operated as the solar energy collection system, it is disconnected from the power grid. The generated DC electricity from each unit is converted by the AC to DC converter in the control unit and is subsequently injected into the power grid. Communication devices in the units and in the control unit form an ad hoc communication network.

Abstract: A solar light power generation system, a control device, and a control method thereof are provided. The solar light power generation system includes: a solar cell array configured to output a plurality of branches of electric energy; a combination control unit configured to receive the plurality of branches of electric energy output by the solar cell array, detect output characteristics of the plurality of branches of electric energy, and adjust combination of series connection and/or parallel connection of the plurality of branches of electric energy dynamically according to the output characteristics, so as to output one or more branches of electric energy; and an energy converting unit, configured to receive the one or more branches of electric energy output by the combination control unit, perform energy converting, and output the converted electric energy. The system adjusts combination of the branches of electric energy.

Abstract: A power supply for a medical device having one or more power consuming components. The power supply system comprises first and second battery cells electrically connected in series to supply a first level of power to the components, and at least one additional battery cell. The power supply also comprises a control system configured to electrically connect the at least one additional battery in parallel with one or both of the first or second batteries upon a detection of a power demand at the components that is greater than said first level.

Abstract: A parallel device comprises a battery module, a plurality of switching units and a control module being couplable to the battery module. The battery module includes a plurality of battery groups. The plurality of switching units includes a plurality of first switches. Each of the switching units is couplable to a respective battery group in series. Each series combination of the switching unit and the respective battery group is coupled in parallel with another series combination, and each of the switching unit includes a respective first switch coupled with a load in series.

Abstract: A photovoltaic power generation system is discussed. The photovoltaic power generation system includes a solar cell module having a plurality of solar cell row groups, a plurality of sensing units respectively connected to the plurality of solar cell row groups, a plurality of amplification units respectively connected to the plurality of solar cell row groups, and a signal control unit that detects currents output from the solar cell row groups in response to sensing signals output from the sensing units, controls a plurality of control signals applied to the amplification units based on the decided signal states, tracks a maximum power based on a voltage and a current output from the solar cell module, and outputs the maximum power.

Abstract: A photovoltaic system comprises a plurality of photovoltaic modules which are electrically connected to a string or to multiple parallel-connected strings and form a PV generator. The first string end forms the negative pole of the photovoltaic generator, and the second string end forms the positive pole. A voltage reduction device is provided with the aid of which the potential of the negative pole is lowered to ground. Advantages with regard to the insulation class of the connecting cable used are also provided.

Abstract: A power supply having a plurality of selectively electrically connectable power cells configured to supply power to a load. The power supply comprises a plurality of power cells electrically connected in series and an auxiliary power cell electrically connected in parallel with one of said plurality of power cells. A control is configured to selectively electrically connect said auxiliary cell in parallel with whichever one of said plurality of power cells has a lower power delivery capability.

Abstract: This is directed to methods, systems, and apparatuses for implementing circuitry that can be used to control multiple solar cells to generate power for a portable electronic device. For example, in response to determining that one or more of the solar cells is generating a reduce voltage output (e.g., due to a partial obstruction of one or more of the solar cells), the connections among the solar cells can be configured to generate a constant preset voltage, as long as a subset of the solar cells is operating. The voltage generated by the solar cells can then be boosted to a value suitable for powering the portable electronic device and/or any of its individual components. As another example, the connections among the solar cells can be configured to generate a startup voltage to directly power the portable electronic device and/or any of its components.

Abstract: A selectable backup power supply device for providing power to a real time clock (RTC) and a memory unit is disclosed. The device includes a backup battery, a first power outputting unit and a second power outputting unit, wherein the backup battery outputs a backup voltage, the first power outputting unit is connected to the backup battery and the RTC for receiving the backup voltage and outputting a first supply voltage to the RTC, and the second power outputting unit is connected to the backup battery and the memory unit, for receiving the backup voltage and, in accordance with a selection signal, outputting a second supply voltage to the memory unit or stopping the output of the second supply voltage.

Abstract: A converter station for connecting an AC system to a bipolar HVDC transmission line. A DC neutral arrangement is provided with first DC breakers enabling breaking of a first current path from a neutral bus of one pole of the transmission line to a neutral bus of another pole at bipolar operation of the station for isolation of a faulty section and changing to monopolar operation/metallic return thereof. The DC neutral arrangement has in the first current path at least two first DC breakers connected in series and adapted to act as a backup for each other would the other thereof fail to break the first current path upon a control to isolate a faulty section by changing from bipolar to monopolar operation.

Abstract: Particular embodiments of the inventive technology disclosed herein seek to reduce or eliminate the risk of damage to components of photovoltaic power circuits such as solar arrays. Aspects of the inventive technology, in embodiments, utilize diode to prevent reverse current flow in the event of application of a voltage to a power supply string which would otherwise effect such flow. Prevention of such reverse current flow may preclude voltages that would otherwise damage reverse current sensitive devices such as switches that may form part of a voltage limiting DC to DC converter.

Abstract: A modular power distribution system comprises a chassis; and a backplane including a power input, and a plurality of module connection locations. A plurality of modules are mounted in the chassis, each module mounted to one of the module connection locations. Each module includes: (i) an OR-ing diode; (ii) a circuit protection device; (iii) a microprocessor controlling the circuit protection device; and (iv) a power output connection location. A circuit option switch is located on each module for setting the current limits for each module. A control module is provided connected to the backplane.

Abstract: A converter unit to improve overall recovered power in a photovoltaic array configuration. Each photovoltaic panel in the photovoltaic array may be coupled to a respective converter unit, which may include a controller to sense an output voltage and output current produced by the solar panel, and manage the output voltage of a corresponding power converter to optimize and regulate the resultant bus voltage to a point which reduces overall system losses, maintains a low loss condition, and removes series-string non-idealities when the panels are series connected. The controller may also adapt to output condition constraints. Instead of single-port regulation, a combination of input voltage and output voltage management and regulation may be performed within the converter. The source voltage and current characteristic may be shaped to correspond to an optimized power curve at the desired bus voltage to allow MPPT tracking according to the DC voltage bus.

Abstract: A power over Ethernet extender arranged to detect if power is received over 2 pairs of wires or over 4 pairs of wires. If power is received over 4 pairs of wires, power is output over only 2 pairs of wires. Preferably, the power signature of the received power is further detected. If the incoming power over a first 2 pairs of wires supports in excess of 13 watts of power consumption, and power is received over 4 pairs, then the output power supports in excess of 13 watts of power consumption; and if the incoming power over a first 2 pairs of wires supports in excess of 13 watts of power consumption, and power is not received over 4 pairs, then the output power does not support in excess of 13 watts of power consumption.

Abstract: A reliable photovoltaic (PV) power system is provided, including a plurality of smart virtual low voltage PV modules arranged in a plurality of columns and a plurality of rows. The smart virtual low voltage PV modules on the same column are connected in series. The smart virtual low voltage PV modules on the same row are connected in parallel. Each of the smart virtual low voltage PV modules comprises: one or more photovoltaic cells, configured to convert solar energy into DC power. The system further includes a DC/DC converting unit, coupled to the PV module, configured to communicate with a control center to acquire from the control center a determined level value, thereby converting the DC power received from the PV module into a demanded output voltage having the determined level value.

Abstract: An electronically reconfigurable battery includes a number of battery modules selectively interconnected by a number of electronic switches, wherein a selectable number of battery modules may be connected either in a series configuration or in a parallel configuration, as a result of placing selected switches of said plurality of switches in open states or closed states. In a parallel configuration, the battery provides power to a primary load, such as a propulsion load for a vehicle. In a series configuration, the battery is configured to provide a high voltage and high power output to a short-term and/or pulsed load, such as an additional load provided on the vehicle.

Abstract: The system allows the generation and distribution of energy on board a motor vehicle provided with a propulsion unit, a tank for fuel at least one distribution network or line for electric energy, electrical energy generation devices connected to the at least one distribution network or line, and a plurality of selectively activatable electrical utilizer devices or apparatus connected or connectable to the at least one distribution network or line. The electrical energy generator devices includes (at least) a microcombustor electricity generator matrix or battery connected to the fuel tank, and a supervision and control unit associated with this generator matrix or battery and coupled to the distribution network or line and arranged to control the operation of the generator matrix or battery in a predetermined manner as a function of the electrical power required or consumed by the network or line.

Abstract: The invention provides a monolithic, highly integrated power supply circuit capable of providing various voltages for circuits on an expansion card, either from a main supply source or an auxiliary supply source. The monolithic power supply circuit preferably includes two switching converters, two low-drop-out regulators, a standby regulator, a reset circuit, and a control circuit. An associated method for providing various voltages via a monolithic power supply circuit is also disclosed.

Abstract: A lavatory system having at least one wash station and at least one electrically operated fixture is disclosed. The lavatory system includes a control system for operating the at least one electrically operated fixture and a power supply system for powering the at least one electrically operated fixture. According to one embodiment, the power supply system includes a plurality of power sources and a switch device. The plurality of power sources are electrically coupled to each other and configured to provide an output voltage for powering the at least one fixture. The electrical coupling of the power sources is selectively adjustable between a first arrangement in which the power sources are electrically coupled to each other in parallel and a second arrangement in which the power sources are electrically coupled to each other in series. The first switch device configured to adjust the electrical coupling of the power sources between the first arrangement and the second arrangement.