Abstract: An energy system for renewable energy applications includes a renewable energy source, a bidirectional inverter connected an AC bus and a DC bus, an energy storage unit connected to the bidirectional DC/DC converter, and a control system comprising one or more controllers coupled to the bidirectional inverter and the bidirectional DC/DC converter. The bidirectional inverter is connected to the renewable energy source and a bidirectional DC/DC converter through the DC bus. The system is configured to capture low power of a photovoltaic (PV) array, energy typically lost to inverter clipping, and through the utilization of ramp rate control.

Abstract: A method includes activating electrochemical cells of a cell assembly to output electrical energy in accordance with a superordinate clock signal in order to have an activation and/or switch-off time points of the respective cells on the basis of the superordinate clock signal not all occur at the same time. To reduce the complexity of smoothing the total battery voltage, the switching time points according to the disclosure are shifted on the basis of the superordinate clock signal for the first cell in accordance with a first switching specification by a cell-specific first clock shift signal.

Abstract: Methods and apparatus may provide for the adaptive operation of a solar power system (3). Solar energy sources (1) and photovoltaic DC-DC power converters (2) may be interconnected in serial, parallel, or combined arrangements. DC photovoltaic power conversion may be accomplished utilizing dynamically adjustable voltage output limits (8) of photovoltaic DC-DC power converters (2). A photovoltaic DC-DC power converter (2) may include at least one external state data interface (7) receptive to at least one external state parameter of a solar power system (3). A dynamically adjustable voltage output limit control (12) may be used to relationally set a dynamically adjustable voltage output limit (8) of a photovoltaic DC-DC power converter (2). Dynamically adjusting voltage output limits (8) may be done in relation to external state parameter information to achieve desired system results.

Abstract: A communication host and a photovoltaic power generation system are provided. The communication host includes an acquiring module, a determining module and a control module. The acquiring module is configured to acquire an operating state parameter of the system. The determining module is configured to determine whether the optimizer meets a first preset triggering condition based on the operating state parameter. In a case where the optimizer meets the first preset triggering condition, a first triggering instruction is transmitted, to instruct the system to decrease, in response to the first triggering instruction, the direct current bus voltage of the grid-connected inverter, and/or a second triggering instruction is transmitted, to instruct the system to increase, in response to the second triggering instruction, an output voltage limiting value of at least one of the optimizers meeting the first preset triggering condition.

Abstract: An inverter system includes an input inverter including a positive and a negative DC input terminals and first and second AC output terminals; and a bidirectional inverter device, including a first bidirectional subinverter and a second bidirectional subinverter. The first and second bidirectional subinverters have DC terminals that are interconnected in parallel with a DC power storage device. The first bidirectional subinverter have first and second AC terminals. The first AC terminal is connected to the first AC output terminal of the input inverter. The second bidirectional subinverter have first and second AC terminals. The first AC terminal is connected to the second AC output terminal of the input inverter. The second AC terminal of the first bidirectional subinverter and the second AC terminal of the second bidirectional subinverter are interconnected.

Abstract: A DC/DC converter includes a first low-voltage terminal point, a second low-voltage terminal point and a third low-voltage terminal point, and a first high-voltage terminal point and a second high-voltage terminal point. The first low-voltage terminal point and the first high-voltage terminal point are directly connected to one another, and an actively drivable switching element, a capacitor and a further switching element are connected in series between the first high-voltage terminal point and the second high-voltage terminal point. The capacitor is connected between the second low-voltage terminal point and the third low-voltage terminal point, a further capacitance is directly connected between the second low-voltage terminal point and the third low-voltage terminal point, and the further capacitance is decoupled from the capacitor at two terminals by two inductors, respectively.

Abstract: An inverter device includes a circuit configuration for converting, to AC power, DC powers respectively given from a first power supply and a second power supply which outputs power with voltage lower than that of the first power supply. The inverter device includes: a first step-up circuit; a second step-up circuit; an inverter circuit connected to both step-up circuits connected in parallel to each other, the inverter circuit configured to convert powers given from both step-up circuits to AC power; and a control unit configured to multiply a power value including the AC power outputted from the inverter circuit, by a ratio of a power value of the DC power of each step-up circuit to a total power value obtained by summing the DC powers of both step-up circuits, and set a current target value for each step-up circuit based on a value obtained by the multiplication.

Abstract: Systems and methods for controlling an energy storage system are provided. In particular data indicative of a load profile can be received. The load profile can specify one or more amounts of power to be delivered by an energy storage system over a duration. The energy storage system can include one or more energy storage elements of a first type and one or more energy storage elements of a second type. One or more time windows associated with high power events and one or more time windows associated with high energy events can then be determined based on the load profile. Power delivery by the energy storage elements of the first type and the energy storage elements of the second type can then be controlled based at least in part on the determined time windows.

Abstract: A power converter includes a power conversion circuit converting an input voltage into an output voltage, and a feedback control circuit including a voltage detector module generating a feedback signal having a signal frequency proportional to a magnitude of the output voltage, a phase detector module generating counting-up and counting-down signals based on the signal frequency and a reference frequency, and a control input generator module controlling the power conversion circuit to adjust the output voltage based on the counting-up and counting-down signals. The logic levels of the counting-up and counting-down signals are maintained until a relative relationship between the signal frequency and the reference frequency changes.

Abstract: An electrified vehicle high voltage battery pack has series-connected battery units or cells combining to provide the high voltage. To power a low voltage bus (e.g., for low voltage accessories or charging a low voltage battery) in a balanced manner, a plurality of DC/DC converters each has an input coupled to a respective battery unit and the converters have respective outputs coupled in parallel to the low voltage bus. A first loop controller receives an actual bus voltage. The first controller generates a target current in response to the bus voltage adapted to regulate the actual bus voltage to a target voltage less than the high voltage. A second controller distributes the target current into a plurality of allocated current commands for respective converters according to respective states of charge of the battery units connected to the converters.

Abstract: Methods and apparatus for controlling a voltage source converter to energize a DC link. A voltage order generating module generates a voltage order for controlling the voltage source converter to generate a DC voltage on the DC link. the voltage order is based on a time varying voltage reference signal. A voltage reference module, which may include a ramp generator generates the time varying voltage reference signal such that the rate of change of the voltage reference signal changes over time. The rate of change of the voltage reference signal may decrease over time, to become more gradual as the nominal operating voltage is reached to avoid over-voltages.

Abstract: To establish a system capable of efficient operation control between a plurality of distributed power sources without undermining the versatility of the distributed power sources, a power control system controls a power generation device and other distributed power sources, the power generation device generating power while a current sensor detects forward power flow. The power control system includes: a power control device including an output unit configured to output power supplied from the other distributed power sources, in a state where the power generation device and the other distributed power sources are paralleled off from a grid; and a dummy output system configured to supply a dummy current detectable by the current sensor as a current in the same direction as the forward power flow, using an output from the output unit, wherein the dummy output system includes step-down unit located between the output unit and the current sensor.

Abstract: Disclosed is a subnetwork controller for a subnetwork within an interconnected grid. The controller controls power generators, subnetworks, or loads of the subnetwork in accordance with sensor-captured internal measured variables and sensor-captured external measured variables as well as external controlled variables of the subnetwork in such a way that a dynamic behavior of the subnetwork in relation to its adjacent subnetworks corresponds to a defined desired behavior.

Abstract: A multiphase power supply includes a multiphase converter including first and second converters having differing operating phases, each of the first and second converters configured to convert input power into driving power, and transmit the driving power to a power amplifier, a detector configured to detect a voltage based on the driving power, and a duty controller configured to compare an error voltage between an envelope signal of an input signal input into the power amplifier and the detected voltage and sawtooth wave signals having different phases from each other to generate duty control signals, wherein the duty controller compares the error voltage and the sawtooth wave signals with each other using a single comparator.

Abstract: An improved interface for renewable energy systems is disclosed for interconnecting a plurality of power sources such as photovoltaic solar panels, windmills, standby generators and the like. The improved interface for renewable energy systems includes a multi-channel micro-inverter having novel heat dissipation, novel mountings, electronic redundancy and remote communication systems. The improved interface for renewable enemy systems is capable of automatic switching between a grid-tied operation, an off grid operation or an emergency power operation.

Abstract: An LED driver design has a single controller used to drive multiple strings of LEDs. In one aspect there is dynamic threshold voltage setting so that the individual characteristics of the LED strings can be taken into account in the voltage control loop. In another aspect, excess energy is dissipated off-chip in a dedicated heat dissipater, and the routing of current to the heat dissipater is controlled dynamically such that a desired integrated circuit biasing remains stable.

Abstract: A static synchronous compensator device connected between a source and a load of a three-phase power system, comprising: a main feedback line configured to provide a main feedback signal from lines between the source and the load; a mixer configured to mix the main feedback signal with a balance function to generate a balanced signal; a signal controller configured to convert the balanced signal to a controlled signal; a gain circuit configured to multiply the controlled signal by ?1 and to perform proportional gain and integral gain (P & I) processing on the controlled signal to generate an intermediate correction signal; and a pulse width modulator configured to apply a pulse width modulation pattern to modulate the voltage source inverter to generate an AC waveform that is applied to the lines between the source and the load.

Abstract: A battery charger for electric vehicles includes at least three identical current controlled AC-DC converter modules having reverse current protected outputs connected in parallel to a charge terminal of the battery.

Abstract: In a first section including a point of time when sums of periods while upper arm-side switches in a pair of current paths of a voltage source inverter conduct in one cycle of a carrier are equal to each other at zero, a first voltage command group corresponds to switching signals in which a period while the upper arm-side switches in all of the current paths are nonconductive in this one cycle is adjacently sandwiched by a pair of periods while all of the upper arm-side switches in the pair of current paths are nonconductive and other upper-arm side switch conducts.

Abstract: A power controller of a hybrid vehicle includes: a first drive motor that drives any one of a front wheel and a rear wheel of a vehicle; an engine that drives the one wheel or the corresponding other one of the front wheel and the rear wheel of the vehicle through a clutch; a generator that is driven by the engine; and a voltage transformer that steps down generated electric power supplied to the first drive motor and a battery from the generator. The power controller limits passing power of the voltage transformer according to the temperature of the voltage transformer, and connects the clutch when the passing power of the voltage transformer is limited.

Abstract: The module according to the present invention is used for accumulating/drawing electricity in/from an electric accumulator (502); the module comprises first terminals and second terminals; the first terminals are adapted to be connected to a photovoltaic panel (501) and to an inverter (504), and the second terminals are adapted to be connected to the electric accumulator (502); the module comprises a conversion unit (503) adapted to be connected between the first terminals and the second terminals; the conversion unit (503) comprises, in turn, a two-way DC/DC converter (550) adapted to convert a first energy flow generated by the photovoltaic panel (401, 501) to store it in the accumulator (502) and a second energy flow drawn from the accumulator (502) to supply it to the inverter (504), the two-way DC/DC converter (450, 550) is configured to convert said first energy flow and said second energy flow in a selective manner.

Abstract: The invention relates to a control system for compensating undesired electrical harmonics on an electrical grid. Part of the control system referred to as a harmonic compensator is operatively connected with a power inverter of a power producing unit supplying power to the grid. Another part of the control system, referred to as an impedance detector, is operatively connected to a point of coupling to which point one or more power producing units are connected. The impedance detector is configured to scan impedances as a function of frequency to identify frequencies of impedance peaks which peaks are indicative of resonance frequencies. The determined resonance frequencies are supplied to one or more the harmonic compensators. A compensator determines control signals to the inverter which causes the inverter to inject compensation currents to the grid which currents will damp currents oscillating at or close to the determined resonance frequency.

Abstract: A motor drive device includes a forward converter, reverse converter, DC link capacitor, voltage detection part, first storage part storing a threshold for the non-energized period in which the leakage current of the capacitor increases and a threshold for the applied voltage for reducing the leakage current of the capacitor, a second storage part that records a previous energization period of the capacitor, and a control part, in which the control part obtains the non-energized period of the capacitor based on the previous energization period recorded, during activation of the motor drive device, and in a case of the non-energized period obtained being longer than the threshold for the non-energized period stored, causes regeneration operation from the motor to the power supply to stop, and causes the voltage of the capacitor to rise up to the threshold for the applied voltage stored, by way of deceleration energy of the motor.

Abstract: According to one embodiment, a drive device drives “N” number (N is an integer of “2” or greater) of inverters to generate AC power and transmit respective AC power to transmission coil units corresponding thereto and includes a switching signal generation circuit. The switching signal generation circuit generates switching signals to drive first to fourth switching elements of each inverter to complementarily drive the first switching element and the second switching element, and complementarily drive the third switching element and the fourth switching element so that a phase difference between an output current of an “M”th (“M” is an integer of 2 or greater and “N” or below) inverter and an output current of an “M?1”th inverter becomes or approach “360×L/N” degrees (“L” is an integer of “1” or greater and less than “N”) and supplies the switching signals to the first to fourth switching elements of the inverters.

Abstract: Disclosed embodiments relate to power supply systems for supplying power. In some embodiments, a power supply system includes: a plurality of power conversion systems configured to receive and convert DC power from a power generator which generates power or an energy storage system which discharges stored energy; and a system controller configured to transmit a control instruction to control the plurality of power conversion systems based on a transmission protocol depending on an attribute of the control instruction.

Abstract: The present invention relates to an intra-module DC-DC power converter and a Photovoltaic (PV) module comprising same. The switching frequency of said intra-module DC-DC power converters may be 500 kHz. The PV module may have a controller and a plurality of switches for allowing each individual string of said PV module to be connected to one corresponding DC-DC converter, or for allowing two or more strings of said module to be connected in series and to apply the voltage of the combined string to a single DC-DC converter. The input voltage range of the DC-DC converters may be 10V to 30V, and the output voltage range may be 120V. The DC-DC converters may be connected in series or in parallel. Multiple such PV panels may be connected in a DC-grid.

Abstract: A power supplying apparatus includes a first piezoelectric transformer operated at a first operating frequency, a second piezoelectric transformer operated alternately with the first piezoelectric transformer and operated at a second operating frequency, wherein the second operating frequency is a multiple of the first operating frequency.

Abstract: In accordance with an embodiment, a method includes converting power by a power converter circuit having a plurality of converter cells coupled to a supply circuit. Converting the power includes a plurality of successive activation sequences and, in each activation sequence, activating at least some of the plurality of converter cells at an activation frequency. The activation frequency is dependent on at least one of an output power and an output current of the power converter circuit.

Abstract: The present invention discloses a driving circuit and a liquid crystal display device. The driving circuit has: a first to fourth diodes, a first and second capacitors, and an adjustable voltage source, An anode of the first diode inputs a voltage, cathodes of the first to third diodes are connected to anodes of the second to fourth diodes, a cathode of the fourth diode outputs a voltage, a first end of the first capacitor is connected to a common end of the first diode and the second diode, a second end of the first capacitor is connected to an output terminal of the adjustable voltage source, and a selective terminal thereof is used to input a selective voltage; when an input voltage is not changed, the selective voltage is different and an output voltage is different. The above-mentioned method can provide multiple different output voltages to meet with client's requirements.

Abstract: A micro grid stabilization device coupled to a DC bus and an AC bus in parallel is provided. A DC power generation apparatus provides power to the DC bus. An AC power generation apparatus provides power to the AC bus. A converter is coupled between the DC bus and the AC bus to transform the voltage of the DC bus and provide the transformed voltage to the AC bus. When the voltage of the DC bus or the AC bus is unstable, the micro grid stabilization device provides power to at least one of the DC bus and the AC bus to stabilize the power of the DC bus and the AC bus.

Abstract: The present disclosure relates to a photovoltaic power installation configured to deliver power to a power distribution grid at a point of common coupling, the photovoltaic power installation including a determination unit configured to determine an amount of self-consumed power of the photovoltaic power installation, and a first power inverter configured to generate power in accordance with 1) the determined amount of self-consumed power, and 2) a power level to be delivered at the point of common coupling. The disclosure further relates to an associated method.

Abstract: Disclosed is a power generation system provided with a renewable-energy-based electric power generator, capable of efficiently and stably outputting electric power at a predetermined power amount. The power generation system includes at least an electric power generator and a maximum power amount detection control unit that performs control such that a voltage and a current at the maximum power point can be detected at any time to output the result as a detection value. The power supplied from a variable voltage power source is selected when the voltage is short. In contrast, the power supplied from a constant voltage power source is selected when the current is short.

Abstract: A vehicle mutual-charging system and a charging connector are provided. The system includes: a first electric vehicle (1002) and a second electric vehicle (1003), each of the first electric vehicle (1002) and the second electric vehicle (1003) including a power battery (10), a battery manager (103), an energy control device (1005) and a charge-discharge socket (20), in which the energy control device (1005) includes: a three-level bidirectional DC-AC module (30), a charge-discharge control module (50), a control module (60); and a charging connector (1004) connected between the first electric vehicle (1002) and the second electric vehicle (1003) and including a first charging gun adaptor connected with the charge-discharge socket (20) of the first electric vehicle and a second charging gun adaptor connected with the charge-discharge socket (20) of the second electric vehicle at both ends thereof respectively.

Abstract: A method for the closed-loop control of a voltage in a distribution network that supplies nodes with voltage via mains power lines. A node, which recognizes that the local voltage of the distribution network present at the node lies above or below a permissible supply voltage range, switches from slave mode to master mode and in the master mode regulates the local voltage that is present, by drawing or supplying reactive power in order to reach the permissible supply voltage range. The node then indicates this to other nodes of the distribution network that are in slave mode by modulating an indication signal pattern onto the reactive power being drawn or supplied by the node. The signal pattern has a signal parameter which is proportional to the amplitude of the reactive power that is drawn or supplied by the node.

Abstract: A circuit that stores characterized loss information for a buck converter and uses the characterized loss information instead of measurements involving output power dependent losses. The characterized loss information may include the characterized switching loss, the characterized ripple loss, etc. The circuit may then calculate the output power, efficiency, power dissipation, etc. without needing to measure the output current.

Abstract: Diffraction of a noise may be reduced in an inexpensive manner without reducing power generation efficiency. A power generation control apparatus (10) includes a plurality of combinations of DC input terminals (101) and (102) for inputting DC power and a noise filter (11) connected to the DC input terminals (101) and (102), wherein each of the plurality of combinations has a different extreme value of frequency characteristics of the noise filter (11).

Abstract: A multilevel converter has a central device for controlling operations and a plurality of series-connected sub modules that each has a first switch, a second switch, and a capacitor. At least two of the sub modules form a multi module, wherein, in charging phases and in discharging phases of the multi module, one of the switches of each sub module is switched off and the other switch of each sub module is switched on. The multi module has a control device that is connected to the central device and undertakes control of the sub modules of the multi module on the basis of control signals from the central device. The control device is configured such that it monitors the capacitor voltages of the sub modules and, in the event of an imbalance in the capacitor voltages, brings about balancing.

Abstract: A multi-inverter system with at least a string of inverters sharing a DC bus and outputting to a shared AC bus. Inverters are hot-swappable and configured to be turned on or off during powered cycles. Central control may comprise reducing power point tracking redundancies or promoting other operational changes at individual inverters of a group.

Abstract: A method and device for monitoring and suppressing a resonance are provided, which are applied to a grid-connected generation system. A current sample voltage of a preset sample point of the grid-connected generation system is monitored in a real time manner; amplitudes of harmonics of the current sample voltage are acquired using a preset algorithm; it is verified whether a resonance occurs in the grid-connected generation system currently based on the acquired amplitudes of the harmonics; in a case that the resonance occurs in the grid-connected generation system, current corrections of parameters of inverters in the grid-connected generation system are acquired according to a preset rule and the parameters of the inverters are adjusted using the current corrections and a selected resonance suppressing algorithm.

Abstract: Solar cells that include quantum dots are provided. In particular, a solar panel is provided, the solar panel comprising: a first solar cell comprising: a first set of quantum dots in a first semiconductor, the first semiconductor configured to receive one or more of ambient light and sunlight and emit first wavelengths a first range of about 450 nm to about 480 nm, the first set of quantum dots configured to convert the first wavelengths to a first electric output; and, a second solar cell comprising: a second set of quantum dots in a second semiconductor, the second semiconductor configured to receive one or more of the ambient light and the sunlight and emit second wavelengths a second range of about 600 nm to about 700 nm, the second set of quantum dots configured to convert the second wavelengths to a second electric output.

Abstract: Disclosed is an energy mixer having a first active diode coupled between a first input node and an output node, and a second active diode coupled between a second input node and the output node. A first capacitor is coupled between the first input node and a dynamic node, and a second capacitor is coupled between the second input node and a third node. Switching circuitry is configured to selectively couple the dynamic node between a fixed voltage node and the second input node in response to a control signal provided by control circuitry. When an output voltage at the output node is within a first range, the dynamic node is coupled to the fixed voltage node and when the output voltage is within a lower voltage second range, the dynamic node is coupled to the second input node such that first capacitor and second capacitor are coupled in series.

Abstract: Optimum power tracking for distributed power sources may be provided by a family of power system architectures having distributed-input series-output (DISO) converters. The DISO converters may be controlled to achieve uniform input voltages across their respective distributed power sources while also tracking an optimum power point of the power system. Each DISO converter may be operably connected to a corresponding power source to form a power-processing channel. A controller may be operably connected to the plurality of DISO converters to control the operation thereof.

Abstract: A method of controlling a plurality of DC/AC converters in cascade configuration, each being arranged to receive an input direct current and voltage from a respective photovoltaic panel and to deliver an electric output. The method includes receiving information representing at least one of frequency, phase, amplitude and harmonics of a required AC, and receiving information on the input direct current and voltage to each one of the plurality of DC/AC converters. Based on the received information, each one of the plurality of DC/AC converters is individually controlled in such manner that the combined output from the plurality of DC/AC converters produces an AC matching the required AC.

Abstract: In a power control system which connects power from the power storage device to a power grid and supplies power to a load, the power from the power storage device is connected to the load and the power grid via a DC/DC converter, a smoothing capacitor, and a DC/AC converter. By a first power control unit for controlling flow power of the power grid to be a power command value, and by a second power control unit for suppressing reverse flow power, an output power command for the DC/AC converter is generated, an output power command for the DC/DC converter is generated so that voltage of the smoothing capacitor becomes target voltage, and the output power command is corrected so as to suppress voltage variation in the smoothing capacitor.

Abstract: An inverter energy system supplies power to a site. The inverter energy system comprises a number of solar strings, each solar string including a solar panel(s) as a renewable energy source and an inverter. The inverter energy system is connected to a mains power supply (grid) and to a site load (sub circuits). The forward or reverse power flow into or out of the mains power supply is monitored at a monitoring point at the site. A rate limit is set for power flow into and/or or out of the mains power supply. The supply of power from the inverter energy system is controlled so that the power flow into or out of the mains power supply is within the set rate limit.

Abstract: A method and apparatus is disclosed that can intelligently invert DC power from single or multiple DC sources to single-phase, split-phase, or three-phase AC power, supply the AC power to the electric power grid when the grid is on, or supply AC power to electric devices or loads when the grid is down. A Smart and Grid-Flexible Power Inverter, or On/Off-Grid Power Inverter, is disclosed that can work in either the on-grid or off-grid mode, and switch back and forth between the two modes manually or automatically depending on the power grid conditions. The system provides a simple and cost-effective solution for areas where the power grid has frequent outages or long downtimes.

Abstract: The present invention provides for a photovoltaic system and circuit having array shedding functionality. The system and circuit, in general, have at least two photovoltaic strings, at least one inverter; and, an array shedding and harvesting functionality configured to monitor the inverter and either disconnect or connect inputs of the at least two photovoltaic strings as needed to produce power for the at least one inverter or to produce power for storage. The array shedding and harvesting functionality is preferably integrated between photovoltaic (PV) strings and the output of the inverter. Various embodiments provide for sensors integrated on each of the inputs of a power assembly combiner, current sensors used to sense current provided on each of multiple inputs from power sources (PV arrays or combiners), and direct current (DC) contactors used to control connection of power source inputs.

Abstract: The invention relates to a power supply unit (3) for supplying power to an on-board electrical network of a vehicle, including: at least two DC-to-DC converters (9A, 9B) which are interleaved and reversible between an opera-ting mode for lowering voltage and an operating mode for raising voltage, the converters (9A, 9B) being intended for being connected to a power storage device (ST2) and being capable of supplying current to the on-board network; and a switch (K) enabling a power source (STI) to supply power to the on-board network when the switch (K) is in a first state, and enabling the power storage device (ST2) to supply power to the on-board network when the switch (K) is in a second state.

Abstract: In one embodiment, a current-fed modular multilevel dual active-bridge DC-DC converter suitable for medium voltage direct current (MVDC) grid or high voltage direct current (HVDC) grid integration is described. The DAB modular converter and the current-fed DAB converter are soft-switched modular multilevel dual-active-bridge (DAB) converters having DC fault ride-through capability. In an additional embodiment a voltage-fed isolated modular dual active-bridge DC-DC converter for medium voltage direct current (MVDC) or high voltage direct current (HVDC) grids or systems is described. In specific embodiments, the converters may be coupled to a battery energy storage system (BESS), wherein the BESS comprises split-battery units and the interface of the isolated DC-DC converter connects the split-battery units to the MVDC or HVDC system.

Abstract: The method of converting high voltage AC lines into bipolar high voltage DC systems makes use of the three transmission lines (referred to as the positive pole, the negative pole, and the modulating pole) in an existing high voltage AC system as transmission lines in a bipolar high voltage DC system. When current from the power source is up to the thermal current limit of the transmission lines, the transmission lines operate in two-wire mode, where current is delivered in the positive pole and returned in the negative pole, the modulating pole being open. When power source current exceeds the thermal current limit, operation is in three-wire mode, alternating for predetermined periods between parallel configuration of the positive pole and the modulating pole to divide current for delivery to the load, and parallel configuration of the negative pole and the modulating pole, dividing the return current.