Abstract: There are provided a substrate; a main body case; and a first locking member and a second locking member for fixing the substrate and the main body case, the substrate includes a first receptacle connector configured to be coupled to a first plug of a first cable, a second receptacle connector configured to be coupled to a second plug of a second cable, a first coil that supplies electric power to the first receptacle connector, and a second coil that supplies electric power to the second receptacle connector, a distance from the first locking member to the first coil is shorter than a distance from the first locking member to the first receptacle connector, and a distance from the second locking member to the second coil is shorter than a distance from the second locking member to the second receptacle connector.

Abstract: The invention discloses a power network flexible controller topology shared by modules. Each single-phase topology comprises an AC/AC converter including N1 CHB modules, and an AC/DC module including N?N1 full-bridge rectifiers; the AC input terminals of N1 CHB modules are connected in series to form an AC port on one side of the AC/AC converter, the AC output terminals of N1 CHB modules are connected in series to form the AC port on the other side of the AC/AC converter, the AC input terminals of N?N1 full-bridge rectifiers are connected in series to form the AC port of the AC/DC module, the AC port on one side of the AC/AC converter is connected in series with the AC side port of the AC/DC module and then connected to a first AC network nd the AC port on the other side of the AC/AC converter is connected in series with the DC side port of the AC/DC module.

Abstract: Disclosed is an apparatus for testing a device, comprising: a switch (100) arranged to replace a circuit breaker (30) associated with an individual system in the device under test, wherein the switch (100) is operable to be controlled remotely from the device under test such that the switch (100) either activates or deactivates the individual system.

Abstract: A power control system, which enables more effective utilization of electrical power generated by using renewable energy, includes a monitoring unit, an output control unit, and a power storage control unit. The monitoring unit monitors the amount of electrical power generated by a power generation device using renewable energy and the amount of electrical power purchased by a consumer through utility grid. When the amount of purchased electrical power is less than a first threshold on the basis of a monitoring result of the monitoring unit, the output control unit suppresses output of electrical power generated by the power generation device. When the amount of the purchased electrical power is less than a second threshold which is greater than the first threshold on the basis of the monitoring result, the power storage control unit charges a storage battery with the generated electrical power outputted by the power generation device.

Abstract: An electrical power distribution system includes a first power bus operating in a first voltage range and a second power bus operating in the first voltage range. A first eFuse circuit selectively couples a power source to the first power bus. A second eFuse circuit selectively couples the power source to the second power bus. A first accumulator is coupled to a first node between the first eFuse circuit and the first power bus. A second accumulator is electrically coupled to a second node between the second eFuse circuit and the second power bus. The first eFuse circuit opens in response to a first electrical fault at the first power bus, and the second power bus is powered with the power source or the first accumulator. The second eFuse circuit opens in response to a second electrical fault at the second power bus, and the first power bus is powered with the power source or the first accumulator.

Abstract: A charging device comprising a first power converter configured to provide a first output power, a second power converter configured to provide a second output power. A switch is coupled to the first power converter and the second power converter. A first socket is configured to deliver the first output power from the first power converter to a first powered device. A second socket is configured to deliver the second output power from the second power converter to a second powered device. A power delivery (PD) controller configured to detect a coupling of the first socket to the first powered device. In addition, the PD controller is configured to detect an absence of coupling of the second socket to the second powered device. Furthermore, the PD controller is configured to control the switch to provide the first output power and the second output power to the first powered device.

Abstract: Various embodiments of the present invention include systems and methods for generating and conserving power for illuminating a space including obtaining energy producing equipment further including a racking system, a direct current to alternating current inverter, a solar module, a light source and connecting the solar module to the racking system, connecting the direct current to alternating current inverter to the solar module, connecting the light source to the solar module through the direct current to alternating current inverter, receiving from the solar module by the inverter a direct current and converting it to alternating current, and causing by the alternating current the light source to visually illuminate the space.

Abstract: A method is provided that includes grouping a plurality of ports at power sourcing equipment receiving pulse power and transmitting power from the group of ports at the power sourcing equipment to a power interface module operable to combine the power and provide an AC (alternating current) outlet configured to provide AC power to one or more devices.

Abstract: The present invention provides a processing circuit, a method, and an electronic device for multiple power supply ports. The processing circuit includes N control modules and a bus. Each control module is correspondingly connected to a power supply port. The communication interface of each control module is connected to the bus. The bus is a one-wire bus and is connected to a power line ground through a resistor. The control modules transmit value signals to the bus. The varied range of a first physical quantity of a bus signal carried by the bus is related to first physical quantities or second physical quantities of all target signals transmitted to the bus. The control module detects the first quantity of the bus signal through the communication interface and adjusts the operating parameter of the connected power supply port according to the varied range of the detected first physical quantity.

Abstract: A power distribution circuit for providing electric power from a plurality of power supplies to a plurality of loads comprises a combiner of power outputs of the power supplies to provide power at a given voltage to a plurality of hot swap modules that are each electrically connected to the combiner and to a power input of a corresponding load. Each hot swap module verifies one or more conditions selected from the given voltage being at least equal to a minimum voltage threshold, the given voltage not exceeding a maximum voltage threshold, and a current consumed by the load not exceeding a maximum current threshold. Each hot swap module delivers power to the power input of the corresponding load when all selected conditions are met and isolates the power input of the corresponding load from the power supplies when any one of the selected conditions is not met.

Abstract: An electrical distribution site energy management and router device, or SER device, may be installed between a customer premises and a distribution grid, and one or more alternative energy sources and energy storage devices may be electrically connected to the SER device. The SER device may intelligently route power from alternative energy sources to the customer premises, energy storage devices, even to the grid, through various modes of operation. The SER device may efficiently and economically route power during peak electricity price periods and outside of peak periods.

Abstract: The parallel assembly of rectifier modules includes a plurality of rectifier modules connected in parallel, a switch for switching-in and switching-out of the rectifier modules, an assembly frame, being provided therein with a switch accommodating space and a rectifier module accommodating space; a DC bus bar, being arranged at the top of the assembly frame; a plurality of groups of connectors, being fixed at one end close to the back side of the assembly frame; an AC copper bar, being fixed at one end close to the front side of the assembly frame; an extended copper bar, being fixed at one end close to the back side of the assembly frame.

Abstract: A solar system installed at a house or building, which may include solar panels and a solar inverter. When the solar system is installed at the house or building, the power load associated with the solar system might overload an electrical panel. This might force the owner of the house or building to spend thousands of dollars on an electrical panel upgrade. To avoid such an expensive upgrade, a smart load manager (SLM) is disclosed that can communicate with the solar inverter and can control it. The SLM can function as a real-time load shedding device, thereby avoiding the cost of a load center/panel upgrade, while enabling a safe and cost-effective solar system installation.

Abstract: A matchless plasma source is described. The matchless plasma source includes a controller that is coupled to a direct current (DC) voltage source of an agile DC rail to control a shape of an amplified square waveform that is generated at an output of a half-bridge transistor circuit. The matchless plasma source further includes the half-bridge transistor circuit used to generate the amplified square waveform to power an electrode, such as an antenna, of a plasma chamber. The matchless plasma source also includes a reactive circuit between the half-bridge transistor circuit and the electrode. The reactive circuit has a high-quality factor to negate a reactance of the electrode. There is no radio frequency (RF) match and an RF cable that couples the matchless plasma source to the electrode.

Abstract: A DC powered cooking appliance which uses an induction or a resistance based DC heating element and excludes AC powered heating elements and preferably does not rely on directly connected combustion powered heating elements. Some embodiments include wattage of 1500 watts or less, voltages of 40 or 48 volts or more and are installed on a boat, van, rv or bus such that an inverter of that boat, van, rv or bus is not electrically connected to the cooking appliance.

Abstract: An electrical distribution grid energy management and router device, or GER device, may be installed in a distribution grid, and route power from power supply to one or more power consumers. The GER devices described herein may provide platforms to add one or more features to a distribution transformer, provide additional features and benefits to both the utility company and end consumer, and may serve as a platform for providing other features, such as communications services, local and remote management, and intelligence to components of the distribution grid. A GER device may include sensors to measure electrical properties of incoming and outgoing power, and may include an electrical circuit layer having a central DC power stage. A GER device may also include a communications platform for one or more communication devices to communicate with a utility, power consumers, other electrical devices/parties, and/or other GER devices to form a micro-grid.

Abstract: The invention relates to a transformer core with at least one additional leg. Said additional leg is used to form a leakage path. In order to optimize the installation space and for easier connection of the transformer windings, the transformer legs and the additional leakage path legs are not arranged along a common line.

Abstract: The present disclosure provides a high-performance power supply of a wide output voltage range and a control method thereof. The high-performance power supply of a wide output voltage range includes M rectification branches and a serial to parallel conversion module. The technical solution of the present disclosure solves the problem in the prior art that it is still difficult to obtain a good performance within a full output voltage range under a wide output voltage requirement.

Abstract: Provided is a method, apparatus, and computer program for diagnosing an internal short circuit of a battery pack. The method may be for diagnosing an internal short circuit of a battery pack based on a state of charge (SOC) variation amount and a balancing amount of each cell of the battery pack, and the method may include checking an SOC variation amount of the battery pack when the battery pack is in a first state, checking a balancing amount of the battery pack when the battery pack is in a second state, and determining whether the battery pack has an internal short circuit based on the checked SOC variation amount and the checked balancing amount.

Abstract: A master controller controls a plurality of uninterruptible power supply apparatuses each including a slave controller and detection circuits that detect at least a DC input voltage, an AC output voltage, and an output current of an inverter. The master controller generates a first voltage command value and a second voltage command value common to the plurality of uninterruptible power supply apparatuses based on detection values from the detection circuits transmitted from the slave controller of each of the uninterruptible power supply apparatuses. The master controller transmits the generated first and second voltage command values to the slave controller of each of the uninterruptible power supply apparatuses. The slave controller generates a first control signal for controlling a converter in accordance with the received first voltage command value. The slave controller generates a second control signal for controlling the inverter in accordance with the received second voltage command value.

Abstract: An energy harvesting electrophoretic display is disclosed comprising a photovoltaic cell that converts part of the incident light to electric current or voltage, wherein the electric current or voltage is used for the operation of the electrophoretic display upon the conversion or stored in a storage component to be used for the operation of the electrophoretic display.

Abstract: A converter can include: (i) a first switch having a first terminal for receiving an input voltage, and a second terminal coupled to a first terminal of a second switch; (ii) an inductor having a first terminal coupled to a common node of the first and second switches, and a second terminal coupled to a first terminal of a third switch, where second terminals of the second and third switches are coupled to ground; and (iii) a plurality of output channels coupled to a common node of the inductor and the third switch, where the converter operates in a buck-boost mode, a buck mode, or a boost mode based on the relationship between the input voltage and output voltages of the plurality of output channels.

Abstract: Various embodiments of the present invention include systems and methods for generating and conserving power for illuminating a space including obtaining energy producing equipment further including a racking system, a direct current to alternating current inverter, a solar module, a light source and connecting the solar module to the racking system, connecting the direct current to alternating current inverter to the solar module, connecting the light source to the solar module through the direct current to alternating current inverter, receiving from the solar module by the inverter a direct current and converting it to alternating current, and causing by the alternating current the light source to visually illuminate the space.

Abstract: A power converter includes a voltage conversion unit that provides a first driving voltage at a first output electrode by converting a power supply voltage in response to a first control signal, the voltage conversion unit being configured to provide a second driving voltage at a second output electrode by converting the power supply voltage after a short detection period, the voltage conversion unit being configured to shut down in response to a third control signal, and a short detection unit that generates the third control signal by comparing a magnitude of a voltage of the second output electrode with a magnitude of a reference voltage during the short detection period.

Abstract: A solar panel energy system, energy resource network comprising a plurality of energy resources each capable of delivering a quantum of energy; and a plurality of energy-consuming-devices each capable of accepting a quantum of energy. Each energy resource is associated with an energy-resource-processor which is configured to issue one or more offer-messages in respect of a quantum of energy available for supply from the energy resource Each energy-consuming-device is associated with at least one energy-consuming-processor) that is configured to receive one or more offer-messages in respect of a transaction for receiving a quantum of energy from one of the energy resources The energy-resource-processor and/or the energy-consuming-processor being configured to issue a cryptographically-secured transaction record of the transaction for inclusion within a publicly-available distributed ledger.

Abstract: A combined bi-directional converter and an auxiliary power module circuit for an 800V battery of an electric vehicle. The converter providing a stepped voltage of 400V with a duty ratio of 50 percent. The combined circuit comprises a high voltage side and a low voltage side. A transformer provides an interface between the high voltage side and the low voltage side. The combined circuit comprises a buck and boost mode.

Abstract: A power supply unit for an electronic device includes an input section comprising input terminals connectable to a primary power source, an output section comprising output terminals connectable to the electronic device and outputting at least two secondary voltages having different nominal voltage levels, and a power management section. The power management section is configured to perform a shutdown process upon existence of a shutdown criterion, wherein the emergency shutdown process comprises decreasing each of the secondary voltages down to a predetermined safety level in a controlled manner.

Abstract: An energy storage unit for a motor vehicle battery is provided, having an energy store, particularly configured as a battery cell module, for storing and delivering electric power. A measuring device measures electrical properties of the energy store. An evaluation unit, connected to the measuring device, ascertains the operational status of the energy store from the measurement results of the measuring device. An indicator unit is connected to the evaluation unit for depicting the operational status of the energy store. By ascertaining and depicting the operational status and not just the state of charge of the energy store, it is possible to dispense with separate complex measurements when fitting the energy store, so that an energy storage unit can be checked quickly and efficiently when fitted into a motor vehicle.

Abstract: A solar system installed at a house or building, which may include solar panels and a solar inverter. When the solar system is installed at the house or building, the power load associated with the solar system might overload an electrical panel. This might force the owner of the house or building to spend thousands of dollars on an electrical panel upgrade. To avoid such an expensive upgrade, a smart load manager (SLM) is disclosed that can communicate with the solar inverter and can control it. The SLM can function as a real-time load shedding device, thereby avoiding the cost of a load center/panel upgrade, while enabling a safe and cost-effective solar system installation.

Abstract: A 12 volt automotive battery system includes a first battery coupled to an electrical system, and the first battery includes a first battery chemistry. Further, the 12 volt automotive battery system includes a second battery coupled in parallel with the first battery and selectively coupled to the electrical system via a bi-stable relay. The second battery includes a second battery chemistry that has a higher coulombic efficiency than the first battery chemistry. Additionally, the bi-stable relay couples the second battery to the electrical system during regenerative braking to enable the second battery to capture a majority of the power generated during regenerative braking. Furthermore, the bi-stable relay maintains a coupling of the second battery to the electrical system when the vehicle transitions from a key-on position to a key-off position.

Abstract: A power delivery system may include a power converter configured to electrically couple to a power source and further configured to supply electrical energy to one or more loads electrically coupled to an output of the power converter, and control circuitry configured to select a constraint factor from a plurality of different constraint factors based on at least one of an input voltage to the power converter and a power level available to the power converter, and control the power converter in accordance with the constraint factor.

Abstract: A wireless power transmitter according to various embodiments of the present invention can comprise a plurality of patch antennas, a coil, and a processor. The processor can control such that an electronic device is detected, the plurality of patch antennas and/or the coil is selected as a power transmission circuit for transmitting power for charging the electronic device, and power is transmitted by means of the plurality of patch antennas and/or the coil in accordance with the selection.

Abstract: A battery control system includes T contactor paths connected in parallel between a battery and a load, where T is an integer greater than one. Each of the T contactor paths includes a first contactor and a second contactor connected in series with the first contactor. Each of the T contactor paths includes at least one of a first voltage sensor configured to sense a first voltage between the first contactor and the second contactor; and a current sensor configured to sense current flowing through the first contactor and the second contactor. A second voltage sensor is configured to sense a second voltage at one end of the T contactor paths. A third voltage sensor is configured to sense a third voltage at an opposite end of the T contactor paths.

Abstract: Power distribution network early failure detection method comprising: a waveform is decomposed into an approximation part and detail parts by wavelet transform, wherein the approximation part is referred to as an approximate shape primitive, and the detail parts are referred to as distortion primitives; the distortion primitives are divided into three primitives including harmonics, pulses and other distortions based on extreme points; characteristics of the primitives and time relationships between the primitives are extracted; probability distribution of the waveform is constructed according to the characteristics of the primitives and the time relationships between the primitives; and a judgment result of the waveform is obtained according to probability distribution of waveforms of different types.

Abstract: An apparatus for photovoltaic power generation can include: an inverter; and at least one photovoltaic optimizer, where input terminals of each photovoltaic optimizer are coupled to output terminals of a photovoltaic panel, and output terminals of each photovoltaic optimizer are coupled in series with each other between input terminals of the inverter; where a maximum power point of the photovoltaic panel is tracked in accordance with an input voltage of the inverter when the photovoltaic optimizer operates in a first mode; and the maximum power point of the photovoltaic panel is tracked in accordance with an output voltage of the photovoltaic panel when the photovoltaic optimizer operates in a second mode.

Abstract: A battery management system includes a plurality of balancing resistors that are respectively connected to a plurality of cells that are connected in series to each other, and that respectively form a part of a balancing discharge path of each of the cells, a plurality of balancing switches configured to respectively control a flow of balancing current of the balancing discharge path, a voltage detection circuit configured to detect a voltage of opposite ends of a respective balancing resistor with respect to a balancing target cell among the cells when cell balancing is started, and a balancing control circuit configured to acquire a voltage cumulative value corresponding to a cumulative value of balancing discharge current of the balancing target cell using the voltage of the opposite ends of the respective balancing resistor, and configured to determine whether cell balancing on the balancing target cell is terminated based on the voltage cumulative value.

Abstract: A plus-side main connection line (17) connects electrical equipment (11), (12) to a plus terminal (16A) of a battery (16). A plus-side isolating switch (18) is provided in the plus-side main connection line (17) to connect or disconnect the electrical equipment (11), (12) and or from the plus terminal (16A) of the battery (16). A plus-side auxiliary connection line (20) connects a communication terminal (15) to the plus terminal (16A) of the battery (16) in a position upstream of the plus-side isolating switch (18). A minus-side main connection line (22) connects a minus terminal (16B) of the battery (16) to ground. A minus-side isolating switch (23) is provided in the minus-side main connection line (22) to connect or disconnect the minus terminal (16B) of the battery (16) and or from the ground.

Abstract: Disclosed is a battery balancing apparatus and method. The battery balancing apparatus includes a plurality of balancing circuits, each balancing circuit is connected in parallel to a respective battery cell among a plurality of battery cells and the plurality of balancing circuits are connected in series to each other, in one-to-one relationship; and a control unit operably coupled to each balancing circuit. The control unit selects at least one of the plurality of battery cells as a balancing target, based on a SOC of each battery cell, and outputs an enable signal and a balancing message to each balancing circuit connected to each battery cell selected as the balancing target. Each balancing circuit transmits a first wireless signal and a second wireless signal corresponding to the balancing message by using electric energy stored in each battery cell, when the enable signal is received by each balancing circuit.

Abstract: Systems, methods and apparatus for electric power grid management and communications are disclosed. At least one active grid element is constructed and configured in network-based communication with a server via at least one coordinator. The at least one active grid element communicates Internet Protocol (IP)-based messages with the server via the at least one coordinator in real time or less than 15 minutes interval. The at least one active grid element participates actively in an electric power grid. The at least one active grid element has an energy consumption pattern or an energy supply pattern. The IP-based messages comprise at least one IP packet including a content, a priority, a security, and a transport route. The content comprises an amount of power available for the electric power grid or an amount of curtailment power available at an attachment point of the at least one grid element.

Abstract: A method and apparatus for using MLPE data for characterizing real-world operation a PV module. In one embodiment, the method comprises obtaining a plurality of temperature measurements, wherein each temperature measurement is a measure, by an MLPE proximate to a PV module, of temperature; obtaining a plurality of DC voltage measurements, wherein each DC voltage measurement of the plurality of DC voltage measurements is a measure by the MLPE of a DC voltage of the PV module; obtaining a plurality of DC current measurements, wherein each DC current measurement of the plurality of DC voltage measurements is a measure by the MLPE of a DC current of the PV module; obtaining racking design information with respect to the PV module; and determining a plurality of PV module temperatures for the PV module based on the plurality of temperature measurements and the racking design information.

Abstract: A medium and high voltage energy conversion system is provided. An input terminal of each of high-voltage isolated DC/DC converters in a phase circuit of the system is connected to a common DC bus. Each of the high-voltage isolated DC/DC converters converts, based on an open-loop control strategy or a closed-loop control strategy, a DC input voltage of a cascade module connected to the high-voltage isolated DC/DC converter into an instruction value related to a voltage of the common DC bus. A system controller of the system calculates, based on at least a voltage-current double loop control strategy, a three-phase modulation instruction to be sent to the cascade modules in three phases according to a parameter related to the voltage of the common DC bus, to implement grid-connected control on three phase circuits.

Abstract: A medium-high voltage photovoltaic (PV) power generation system is provided. A PV string of the system is insulated from the ground via an insulator of a medium-high voltage withstanding level, so that the PV string is applicable under a high voltage level. The PV strings are connected to cascade modules. An output voltage of series-connected cascade modules is grid-connected to a 10 kV power grid through a three-phase filter, without a power booster transformer or a high-frequency isolated DC/DC converter in a conventional power station, thereby improving the system efficiency.

Abstract: An electrical distribution grid energy management and router device, or GER device, may be installed in a distribution grid, and route power from power supply to one or more power consumers. The GER devices described herein may provide platforms to add one or more features to a distribution transformer, provide additional features and benefits to both the utility company and end consumer, and may serve as a platform for providing other features, such as communications services, local and remote management, and intelligence to components of the distribution grid. A GER device may include sensors to measure electrical properties of incoming and outgoing power, and may include an electrical circuit layer having a central DC power stage. A GER device may include a physical layer providing a communications platform for one or more communication devices that may communicate with other GER devices to form a micro-grid, a utility, power consumers, third parties, and other electrical devices.

Abstract: A method for controlling an electrical energy distribution network includes connecting at least one first distribution network of a first voltage level which comprises a plurality of network nodes to a power line of the at least one first distribution network, wherein a first part of the network nodes comprises energy consumers, a second part of the network nodes comprises energy generators, and a third part of the network nodes comprises both energy consumers and energy generators. A local unit of each of the network nodes records first energy quantity information which represents a measured energy quantity, and provides second energy quantity information which represents a tradable energy quantity.

Abstract: In one example, a system for parallel output of backup power modules includes a first backup power module coupled to an input and a first output of an enclosure, a second backup power module coupled to the input and a second output of the enclosure, wherein the second backup power module is coupled in parallel with the first backup power module, and a switch coupling the first backup power module and the first output of the enclosure to the second output of the enclosure.

Abstract: The present disclosure discloses a controller based on APP control, disposed between a power source and a lamp strip. The controller comprises: a receiving control unit electrically connected to the power source for receiving a Bluetooth signal or a WIFI signal transmitted by an external smart terminal, and issuing a control signal according to the Bluetooth signal or the WIFI signal; a driving unit electrically connected to the receiving control unit for adjusting a flicker color and a flicker frequency of the lamp strip according to the control signal; and a manual control unit electrically connected to the receiving control unit for inputting a manual signal to the receiving control unit to cause the driving unit to switch the lamp strip to different modes.

Abstract: A drive device comprises a plurality of boost converters connected in parallel to each other and placed between a power storage device side and an electric load side; a drive mode setting switch operated to set a drive mode among a plurality of drive modes; and a control device configured to control the plurality of boost converters by employing one control mode including a first control mode that drives and controls only some boost converters out of the plurality of boost converters and a second control mode that drives and controls a larger number of boost converters than some boost converters. The control device changes a switchover reference value that is used to switch over control between the first control mode and the second control mode according to the magnitude of an electric load, based on a drive mode set by operation of the drive mode setting switch.

Abstract: A power distribution grid for a facility, such as a data center, is located within the facility. The power distribution grid includes a plurality of power transport elements arranged in a grid pattern and nodes located at intersections of the grid pattern. Electrical loads are supplied power via respective nodes of the power distribution grid. Also, each node is supplied power from more than two transport elements, such that one or more transport elements can fail and electrical loads connected to a particular node associated with the failed transport elements continue to receive electrical power supplied to the particular node from at least two different transport elements.

Abstract: A device includes an energy unit coupled to an energy device and adapted to couple a pair of split DC rails. A controller senses the voltage on the DC rails and regulates its output current response by means of an autonomous current response that creates the aggregate effect of controlling the rail voltage in cooperation with other units coupled to the DC rails. A system includes multiple such devices coupled to split DC rails.

Abstract: A method for operating an energy coupling device electrically coupling a high-voltage on-board electrical system designed for d.c. voltage to a low-voltage on-board electrical system designed for d.c. voltage, having a high-voltage energy converter connected to the high-voltage on-board electrical system and a low-voltage energy converter connected to the low-voltage on-board electrical system, which are electrically coupled by means of a d.c. voltage intermediate circuit. The energy converters are controlled by a control unit. The degrees of conversion efficiency of the energy converters are ascertained and an intermediate circuit d.c. voltage of the d.c. voltage intermediate circuit is set as a function of a total degree of efficiency produced by the sum of the degrees of conversion efficiency in order to maximize the total degree of efficiency.