Abstract: Provided is a gradationally controlled inverter formed by series-connection between: a main inverter circuitry which has main inverter arms for outputting AC voltages for respective phases, and to which a voltage of a DC source is applied through a DC busbar; and a sub-inverter circuitry having three single-phase sub-inverters. Each of short-circuit switches is connected between an input terminal and an output terminal of a corresponding one of the sub-inverters. At the time of a failure of the sub-inverter, a bypass for current is formed for only the failure phase by causing short-circuiting at the short-circuit switch connected to the sub-inverter, and only the main inverter arm for the failure phase is operated as a three-level inverter.

Abstract: An OBC controller for vehicle, a system including the same, and a method thereof are provided. The OBC controller includes a measurement device that measures a voltage of each phase of a three-phase OBC and a controller that calculates an impedance of each phase using a voltage of each phase. The voltage is measured before charging of the three-phase OBC starts. The controller also calculates a charging amount for each phase, the charging amount corresponding to the impedance of each phase, and adjusts charging based on the calculated charging amount for each phase.

Abstract: A power controller system comprises multiple power controllers that receive a periodic waveform input and that apply power to multiple loads. A switch-on time and a switch-off time is for each of the power controllers within a cycle of the periodic waveform input. The power controllers generate output waveforms to be applied to the loads that are partial segments of the cycle of the periodic waveform input. Each of the power controllers includes a switchable power component that can be switched on and switched off at any time and that can conduct current in both forward and reverse directions.

Abstract: A power converter can include an input PFC stage that receives a rectified input voltage coupled to a flyback stage including a center-tapped primary winding magnetically coupled to a secondary winding and a main switch coupled in series with the primary winding. The output of the PFC stage can be coupled to the center tap of the primary winding, and an output of the power converter can be coupled to the secondary winding of the flyback stage. The converter can further include control circuitry coupled to the main switch and an auxiliary switch in the PFC stage that operates the main switch to regulate an output voltage of the power converter, selectively enables the auxiliary switch responsive to a low line voltage condition at the input of the power converter, and operates the enabled auxiliary switch synchronously with the main switch.

Abstract: In a power conversion system, a power converter includes a power conversion circuit connected to a direct current (DC) source via a DC distribution line and converts and supplies received DC power to a load, and a power conversion control unit. A power stabilizing device is disposed between the DC distribution line and the power converter and stabilizes a DC voltage applied from the DC power source. A control power source of the power stabilizing device performs current control of the current transformer to suppress DC magnetization caused by a DC current component of the primary current while compensating for a varying component of the DC voltage. The control power source acquires current information or voltage information calculated from control information used by the power conversion control unit for control operations related to energization of the load and uses it as control information for the power stabilizing device.

Abstract: The present disclosure is directed to modular microgrids and more particularly to core modules that comprise self-synchronizing devices that can connect and self-synchronizes voltage, frequency and phase with other power sources. The disclosed embodiments enable a modular power system to serve as the primary or secondary source of power for applications requiring loads from a few kilowatts (KW) to the scale of megawatts (MW). The modular system is generalized to use either a single or multiple power generation sources at once, with the ability to connect and self-synchronize voltage, frequency, and phase of a variety of different types of power sources. Power control systems designed to function with self-synchronizing technology enable a modular power system to satisfy a wide variety of needs and enable new features of resiliency and expandability.

Abstract: An apparatus for high-speed switching between a plurality of power sources includes a switch-mode isolation transformer. The switch-mode isolation transformer includes a plurality of isolated primary windings. Each of the plurality of isolated primary windings can be electrically isolated from others of the isolated primary windings and selectively couplable to a power source of the plurality of power sources. The switch-mode isolation transformer further includes a secondary winding coupled to a load. The apparatus further includes a controller to selectively couple one of the plurality of power sources through a corresponding isolated primary winding, responsive to detecting an adverse condition in another power source of the plurality of power sources. Other methods and systems are also described.

Abstract: A method includes outputting an alternating current (AC) waveform from an inverter module to a plurality of loads, outputting a fault waveform from the inverter module to a first load of the plurality of loads in response to a fault condition associated with the first load, and outputting the AC waveform from the inverter module to at least some of the plurality of loads if the fault condition is cleared before a recovery period expires or disconnecting the inverter module from the plurality of loads if the fault condition is not cleared before the recovery period expires.

Abstract: A multi slope output impedance controller is configured to vary the effective impedance Zeff_n of a power converter to reduce a current imbalance between power supplies in a masterless configuration of N parallel-connected power supplies while maintaining load regulation during start-up and steady-state operation. Generally speaking, the controller commands a high value of Zeff_n when Iout_n is low to facilitate current sharing and reduce current imbalance Ib between the power supplies and commands a low value of Zeff_n when Iout_n is high to improve load regulation.

Abstract: A control system for a three-phase inverter includes an instantaneous value voltage controller and an equivalent effective value voltage controller. The instantaneous value voltage controller is configured to feed back and control an instantaneous value of an inverter output voltage. The equivalent 5 effective value voltage controller is configured to perform an orthogonal decomposition feedback control on an effective value of the inverter output voltage. The equivalent effective value voltage controller is configured to perform integral compensation respectively on a real-axis voltage and an imaginary-axis voltage of a two-phase rotating coordinate system of the three-phase inverter. An output of the instantaneous value 10 voltage controller and an output of the equivalent effective value voltage controller are used to obtain the inverter output voltage through a delay stage transfer function and a controlled object transfer function.

Abstract: A multiphase switching voltage regulator is disclosed. The regulator includes a first clock generator circuit configured to receive a reference clock, and to generate M first clocks, where the M first clocks are phase separated by 360°/M, a plurality of phase extrapolator circuits, where the plurality of phase extrapolator circuits includes N phase extrapolator circuits, and a phase selector multiplexer configured to provide one of the M first clocks to each of the phase extrapolator circuits, where the N phase extrapolator circuits are configured to generate N output clocks, where the N output clocks are phase separated by 360°/N.

Abstract: There is provided a system for providing (e.g., configured to provide) power to one or more loads. The system comprises a plurality of power converters, wherein each power converter is configured to be arranged in a parallel configuration with one or more additional power converters so as to provide power to the one or more loads. The system further comprises a central controller configured to receive a plurality of local current measurement values from each of the power converters, output a global current measurement value based on the local current measurement values, and transmit the global current measurement value to each of the power converters, wherein each power converter comprises an inverter for receiving an input voltage and converting this to an output voltage having one or more associated output current(s).

Abstract: A multi-level inverter topology is disclosed. A power converter circuit converts a DC source at its input to provide an alternating current (AC) at its output. The power converter circuit may have a controller operably attached to multiple series connections of switches. The controller may control one or more of the multiple series connections of switches to convert a DC input to provide multi-level AC voltages with DC offset across two terminals of the power converter circuit. The multi-level AC voltages with DC offset may then be converted by use of a plurality of series connections of switches to provide a single-phase AC voltage at a first output terminal with respect to at least one of a neutral potential, an earth potential, or a terminal of the power converter circuit.

Abstract: An emergency output circuit for starting LED lamp tubes with leakage protection includes a PWM pulse genera tor provided with a PWM chip. When a control terminal detects a power outage, a high level of voltage is instantly output to the PWM chip, and the PWM pulse generator outputs complementary drive PWM rectangular waves with a controllable dead time, which are boosted and filtered into a 250V DC voltage; then, positive and negative alternating square waves are formed through a full-bridge inverter circuit, and two pairs of MOS transistors are turned on alternately through complementary PWM control to generate an AC voltage UAB on an LED lamp tube; and finally, an AC rectangular wave slowly changing into a stable 135V AC output from a 250V DC output is obtained through a correction circuit to replace existing methods to turn on the LED tube, thus effectively simplifying the circuit.

Abstract: A power supply system with dynamic current sharing includes a current-sharing bus and a plurality of power supply units connected to each other through the current-sharing bus. The current-sharing bus provides a first current signal. Each power supply unit includes a local current bus for providing a second current signal. The active current-sharing unit compares the first current signal with the second current signal to generate a compensation voltage. The current-averaging unit compares a difference value between an average value of the first current signal and an average value of the second current signal to generate an average voltage. The droop current unit receives the second current signal to generate a droop compensation voltage. The integration calculation unit makes output currents of the power supply units be approximately equal according to the compensation voltage, the average voltage, and the droop compensation voltage.

Abstract: A portable electric energy storage system and a power regulation method thereof are provided. The portable electric energy storage system includes a housing, and an inverter and an energy storage battery disposed in the housing, and further includes: a power detector configured to detect a present power Pt of a connected load; a first comparator configured to compare the present power Pt with a rated power Pe of the inverter; a first actuator configured to regulate an output power of the inverter to a first preset power P1 if the present power Pt is greater than the rated power Pe of the inverter; and a second actuator configured to gradually regulate the output power of the inverter to a second preset power P2 after the connected load is driven to start operation or operate for a period of time; or determine whether to stop driving output of the load.

Abstract: Systems and methods for multilevel hysteresis current control for a cascaded multi-level converter having a plurality of power cells connected in series with a positive integer number of output voltage levels, and to control any shape of AC/DC current in the load, transfer electrical power from energy storage elements of the power cells to that load and recover the energy back to the storage elements. Systems and methods for voltage balancing on energy storage elements of the power cells to determine whether to inject energy into or extract energy from a selected storage element, and for zero switching state rotation technique of switching elements in each power cell of cascaded multilevel converter.

Abstract: A power control apparatus for a distributed power supply interconnected with a power system includes: a conversion circuit that performs reverse conversion of converting power supplied from the distributed power supply from direct current to alternating current and outputting the converted power; and a control device that controls the conversion circuit. The control device changes a target value of received power at a power reception point of the power system on the basis of a predicted value of a power generation amount of the distributed power supply and a predicted value of power consumption of a demand facility, and controls an output of the conversion circuit such that the received power at the power reception point becomes a target value.

Abstract: A scalable multi-phase switching converter includes: converter modules, each including: a loop control unit, which generates a basic trigger pulse according to a feedback signal in master operation mode; and a switching control unit, which determines an operation mode and a corresponding phase serial order according to a setting signal received by a setting pin in a setting mode, and generates a multi-phase trigger pulse signal at a trigger pin according to the basic trigger pulse in master operation mode. The switching control unit receives the multi-phase trigger pulse signal at the trigger pin in slave operation mode. The switching control unit generates an ON-trigger pulse according to the multi-phase trigger pulse signal and the corresponding phase serial order. An ON-period determination unit generates a conduction control pulse according to the ON-trigger pulse to control a corresponding inductor. The trigger pins of the converter modules are coupled to each other.

Abstract: This disclosure relates to embodiments that include an apparatus that may comprise a first layer including a first plurality of active devices, a second layer including a second plurality of active devices, and/or a third layer including a plurality of passive devices and disposed between the first and the second layers. An active device of the first plurality of active devices and an active device of the second plurality of active devices may influence a state of charge of a passive device of the plurality of passive devices.

Abstract: The present invention provides a Pulse Width Modulation (PWM) method for a Cascaded H-bridge (CHB) converter. Each phase of the converter is provided with n Cascaded H-bridge rectifier circuits, or may also be provided with n Cascaded H-bridge rectifier circuits+1 redundant H-bridge rectifier circuit. The method includes following steps of: S1, generating groups of sinusoidal signals as reference waveforms, and generating n carrier signals having sequentially decreasing levels and equal amplitudes to correspond to the H-bridge rectifier circuit at the first to the nth levels, where the levels of the n carrier signals are cascaded to fill the voltage amplitude of a unipolar half cycle of the reference waveform; and S2, determining PWM signals for controlling power transistors of the corresponding H-bridge rectifier circuits based on each reference waveform and each carrier signal.

Abstract: Systems and methods that facilitate multilevel hysteresis voltage control methods for cascaded multilevel voltage modulators having a plurality of power cells connected in series and has any positive integer number of output voltage levels to control any unipolar voltage on the load of the voltage modulator, and transfer electrical power from an electrical grid via AC/DC converters or directly from energy storage elements of the power cells to that load. A method of operational rotation of the power cells of a multilevel voltage modulator, which ensures an equal power sharing among the power cells and voltage balancing of the energy storage elements of the power cells of the modulator.

Abstract: Provided are embodiments for a system for reducing input harmonic distortion of a power supply. The system includes a power source coupled to a power supply. The power supply includes an input stage that is configured to receive an input signal from the power-supply, wherein the input signal is received at known input frequency, and a converting stage that is operated to convert the input signal to an output signal, wherein the output signal has an output frequency. The power supply also includes an output stage that is operated to generate output power based on the output signal, and a controller that is configured to provide control signals to the output stage of the power supply to modify the output signal. Also provided are embodiments for a power supply and method for reducing input harmonic distortion of the power supply.

Abstract: A power-supply control device capable of reducing a size of a power-supply device including a main power-supply and a plurality of auxiliary power-supply systems and stably supplying electric power to the plurality of auxiliary power-supply systems is provided. The power-supply control device includes a DC/DC converter that steps down a power-supply voltage from a main battery and outputs the stepped-down power-supply voltage to a first auxiliary power-supply system and a second auxiliary power-supply system; and a controller that stops supply of electric power from the DC/DC converter to the second auxiliary power-supply system when a load of a heater is in a predetermined high-load state, and supplies electric power from the DC/DC converter to the second auxiliary power-supply system when the load of the heater changes from the predetermined high-load state to a predetermined low-load state.

Abstract: This invention proposes a single-vector-based finite control set model predictive control for two parallel power converters, which adopts a centralized control structure to achieve accurate control of overall performance. It establishes predictive models for line currents and three phase-circulating currents and constructs a novel cost function that uses these currents as performance indices to implement the predictive control algorithm based on the proposed predictive models. The invention proposes dynamic weighting coefficients and adjustment principles to improve system control performance. A finite set output signal matrix containing important characteristic information of all alternative vectors is constructed to avoid redundant calculations in each control horizon, reducing computation time during practical implementation.

Abstract: A power regeneration device 21 that converts the power of a main engine DC line 16 connected to a main engine power generator 12 through a rectification circuit 14 to supply the converted power to an accessory DC line 34 connected to an accessory power generator 31 through a rectification circuit 32 includes a plurality of power conversion modules 221 to 22N configured such that input sections 221a to 22Na are connected in series. The main engine power generator 12 and a power consumption device 15 are controlled such that a voltage input to the power regeneration device 21 does not exceed a voltage upper limit value Vm and a portion between a positive electrode terminal (+) and a negative electrode terminal (?) of each of the input sections of the power conversion modules to be stopped is short-circuited by a bypass device and the voltage upper limit value Vm is decreased when some of the plurality of power conversion modules 221 to 22N are stopped.

Abstract: A power conversion system includes a first converter configured to convert an input voltage into discrete voltage levels, and provide each discrete voltage level at a corresponding output terminal. The power conversion system further includes a second converter configured to convert the discrete voltages into modulated voltages. The power conversion system further includes a selection unit configured to alternatively output each of the modulated voltage voltages across a pair of output terminals.

Abstract: A persistent DC circuit breaker provides a persistent single or dual DC voltage for a power distribution circuit coupled to a power panel. A control mechanism ensures a constant and consistent DC power output from the persistent DC circuit breaker. The persistent DC circuit breaker can replace an AC circuit breaker to convert an AC power panel into a co-existing AC and DC power panel or an entire DC power panel.

Abstract: The present disclosure relates to a wind turbine comprising a wind turbine rotor with a plurality of blades supported on a support structure, a generator operatively coupled to the wind turbine rotor for generating electrical power, a power electronic converter for converting electrical power generated by the generator to a converted AC power of predetermined frequency and voltage, and a main wind turbine transformer having a low voltage side and a high voltage side for transforming the converted AC power to a higher voltage. One or more electric filters are connected to the high voltage side of the main transformer, wherein the electric filters are arranged in the support structure. The present disclosure also relates to wind farms, and particularly offshore wind farms, and to methods for operating wind farms.

Abstract: An insulation impedance detection method includes: An inverter injects a first common-mode voltage into an alternating current side, where the first common-mode voltage is divided by an alternating current grounding insulation impedance of an alternating current cable and a direct current grounding insulation impedance of a photovoltaic unit. The inverter can obtain an impedance value of the alternating current grounding insulation impedance based on the first common-mode voltage, a voltage divided by the alternating current grounding insulation impedance for the first common-mode voltage (a second common-mode voltage on the alternating current grounding insulation impedance), and an impedance value of the direct current grounding insulation impedance. The alternating current grounding insulation impedance is detected by using a necessary device, namely, the inverter in a photovoltaic power generation system.

Abstract: A 15-level multilevel inverter circuit includes an outer circuit, an inner circuit, a polarity changing circuit and a computing device. The outer circuit and the inner circuit include a plurality of DC voltage supplies. Each DC voltage supply has a positive and a negative terminal. The outer circuit, the inner circuit and the polarity changing circuit include a plurality of unidirectional power switches. Each unidirectional power switch is a transistor with a diode connected in parallel to the transistor. The computing device is configured to provide control signals to the gates of the plurality of the unidirectional power switches of the outer circuit and the inner circuit to add or subtract the voltage of each of inner DC voltage supplies to form square waveforms approximating sinusoidal waveforms, and to the gates of the plurality of the unidirectional power switches of the polarity changing circuit to switch the polarity of the voltage.

Abstract: A power system for an electrical system with highly fluctuating loads is powered by one or more power sources that are slow to react to load changes. The power sources are connected to electrical equipment used on the drill rig which provide active load to the generate. One or more load banks may be positioned to provide passive load to the generators to maintain generally constant generator load, while allowing for instant access to power as active load increases. Generators may be run at 100% capacity, a maximum efficient capacity, or at a high enough level to allow for a sufficiently rapid increase in power output. At least one parameter of a drilling operation may be utilized to anticipate load demand changes.

Abstract: A power conversion apparatus includes a base having a main surface to which switching elements of each of power converters are fixed, capacitor units, coupling members fixed to some of the capacitor units adjacent to each other, and fitting members fixed to the respective capacitor units and fixed to the base. The capacitor units are disposed along the main surface of the base.

Abstract: The present disclosure provides systems and methods for optimizing loading of battery inverters. A system may include a plurality of inverters configured to output power to a load; a switching system connected to the plurality of inverters; a plurality of energy storage units selectively coupled to the plurality of energy storage units by the switching system; and a controller. The controller can be configured to determine a required power for the load; determine a number of the plurality of inverters to provide the required power; determine a switching position for the switching system based on the determined number of the plurality of inverters, the switching position corresponding to power delivery by a set of the plurality of inverters; and send a control signal to the switching system to connect one or more of the plurality of energy storage units with the set of the plurality of inverters.

Abstract: An inverter subsystem that includes a direct current (DC) bus, a DC terminal, and a power storage interface that is configured to be connected to power storage. The DC terminal is configured to be: (1) connected to the DC bus via an internally-facing side of the DC terminal and (2) connected to a load via an externally-facing side of the DC terminal. The load is powered via the DC terminal.

Abstract: A test system is disclosed. The test system includes a programmable switching array including input terminals, output terminals, and an array of programmable switches configured for selectively connecting any one of the input terminals to any one of output terminals; and a current supply device comprising a multiplexed digital bus and a plurality of a power supplies connected in parallel between the multiplexed digital bus and the input terminals of the programmable switching array.

Abstract: A method and apparatus include a primary transformer coil, a secondary transformer coil, and a center tapped inductor coupled to the secondary transformer coil. A first switch may be in electrical communication with the center tapped inductor and may be configured to affect the first output voltage. A second switch may be in electrical communication with the center tapped inductor and may be configured to affect the second output voltage. In a particular example with an analog current (AC) output voltage, the two output voltages are out of phase to each other. In a direct current (DC) implementation, the transformer may be operated to output a positive and a negative output voltage. The apparatus may function as a resonant converter, or may operate in non-resonant mode. In one implementation, an H bridge may provide reactive power support. An inductor filter may be in electrical communication with the secondary transformer coil.

Abstract: A plurality of switching units are provided, and a controller performs control in an antiphase manner to approximately synchronize a rise of a control signal applied to one of the switching units with a fall of a control signal for switching applied to any one of the other switching units and synchronize a fall of the control signal applied to the one of the switching units with a rise of the control signal for switching applied to the any one of the other switching units. When control in an antiphase manner is disabled, control is performed to prevent rises or falls from coinciding with each other between the switching units. Output signals from the switching units are input to rectifiers and are combined by a combiner to become an output signal.

Abstract: A multi-port power converter includes a housing that includes a plurality of ports structured to electrically interface to a plurality of loads, the plurality of loads having distinct electrical characteristics. The multi-port power converter also includes a plurality of solid state components configured to provide selected electrical power outputs and to accept selected electrical power inputs and a plurality of solid state switches configured to provide selected connectivity between the plurality of solid state components and the plurality of ports.

Abstract: A utility-scale energy storage and conversion system can operate two or more inverter groups such that their reactive power commands are proportional to their available reactive power range. The control system can therefore distribute the reactive power commands in proportion to the available Q range, thereby ensuring that all inverters in the utility-scale energy storage and conversion system 100 operate with the same Q “headroom”. In addition, the utility-scale energy storage and conversion system can use an on-load tap changer (LTC) to adjust a terminal voltage associated with a first group of inverters and a second group of inverters. The first group of inverters can be associated with a first rating and the second group of inverters can be associated with a second rating that is greater than the first rating.

Abstract: A power converter includes N power conversion units. Each power conversion unit includes a main switching circuit, a transformer, a synchronous rectifier circuit, an input signal terminal and a signal processor. A primary winding of the transformer is connected with the main switching circuit. The synchronous rectifier circuit is connected with a secondary winding of the transformer. The input signal terminal receives a first PWM control signal. The signal processor generates first and second PWM driving signals to drive the main switching circuit according to the first PWM control signal, and a phase difference between the first and second PWM driving signals is (180±?) degree. The signal processor generates third and fourth PWM driving signals to drive the synchronous rectifier circuit according to the first PWM control signal, and a phase difference between the third and fourth PWM driving signals is (180±?) degree.

Abstract: An oscillator circuit (15) is disclosed. It comprises N amplifier circuits (A1-A4), connected in a ring and has a first and a second supply terminal (s1, s2). Each amplifier circuit (A1-A4) comprises an input transistor (M1) having its gate connected to the input (in) of the amplifier circuit, its drain connected to an internal node (x) of the amplifier circuit, and its source connected to the first supply terminal (si). Furthermore, each amplifier circuit (A1-A4) comprises a first resonance circuit (R1) comprising a first inductor (Ls) and a first capacitor (Cs), wherein the first inductor (Ls) is connected between the internal node (x) and the output (out) of the amplifier circuit, and the first capacitor (Cs) is connected between the output (out) of the amplifier circuit and one of the first and the second supply terminals (s1, s2).

Abstract: A transformerless parallel active rectifier system includes N multiphase common mode inductors directly connected to a shared multiphase AC input with no intervening transformer, and N active rectifiers coupled to respective ones of the N multiphase common mode inductors and having respective DC outputs coupled to a shared DC bus, where N is an integer greater than 1. The N active rectifiers have ground current regulators and are synchronized to provide DPWM switching control signals synchronized to one another to regulate their respective ground currents and concurrently regulate the shared DC bus voltage.

Abstract: Apparatus and method for controlling reactive power. In one embodiment, the apparatus comprises a bidirectional power converter comprising a switched mode cycloconverter for generating AC power having a desired amount of a reactive power component.

Abstract: Systems and methods that facilitate multilevel hysteresis voltage control methods for cascaded multilevel voltage modulators having a plurality of power cells connected in series and has any positive integer number of output voltage levels to control any unipolar voltage on the load of the voltage modulator, and transfer electrical power from an electrical grid via AC/DC converters or directly from energy storage elements of the power cells to that load. A method of operational rotation of the power cells of a multilevel voltage modulator, which ensures an equal power sharing among the power cells and voltage balancing of the energy storage elements of the power cells of the modulator.

Abstract: Module-based energy systems are provided having multiple converter-source modules. The converter-source modules can each include an energy source and a converter. The systems can further include control circuitry for the modules. The modules can be arranged in various ways to provide single phase AC, multi-phase AC, and/or DC outputs. Each module can be independently monitored and controlled.

Abstract: The power supply device with multiple outputs includes two output ports, a power converting module with two power output ends, and two switching modules connected among the two power output ends and the two output ports. The output power from the two power output ends can be independently allocated to either one or two of the two second output ports. When one of the output ports requests for a demand power, the power supply device is able to determine which one or both of the power output ends to output power to the output port, reaching a better power allocation efficiency.

Abstract: A system for dynamically balancing power in a battery pack during charging and discharging includes a battery pack, a control unit, and a load unit. The battery pack includes one or more modules. Each module includes one or more bricks. Each brick includes one or more blocks connected either in a series configuration or in a parallel configuration. Each block includes one or more cells. The control unit is connected with the battery pack across each of the blocks for processing power from each of the blocks irrespective of a power mismatch between the blocks. The control unit dynamically balances the power in the battery pack by controlling a differential current from a block with higher state of charge (SOC) to a block of lower SOC, using one or more converters and thereby maximizing available energy of the battery pack during charging and discharging.

Abstract: A method and associated apparatus for feeding electric power from a photovoltaic system via a grid connection point into an AC grid having a low short-circuit power is disclosed. The method includes connecting a DC voltage side of at least one first inverter of the photovoltaic system to a photovoltaic generator and an AC voltage side of the at least one first inverter to the grid connection point, wherein the at least one first inverter is operated as a current source, and connecting an AC voltage side of a second inverter of the photovoltaic system to the grid connection point, wherein the second inverter is operated as a voltage source based on measurement values of an AC voltage measured in the region of the photovoltaic system and a predefined characteristic curve.

Abstract: A high-voltage hierarchy hundred-megawatt level (100 MW) battery energy storage system and optimizing and control methods are provided. The system includes a multi-phase structure, of which each phase is divided into multi-story spaces from top to bottom. A battery module is provided in each story of the multi-story spaces. The battery module is connected to a DC terminal of an H-bridge converter, and each phase is cascaded by the H-bridge converter. A capacity of the single-phase energy storage apparatus of the present invention is large, and multiple phases can be connected in parallel to form a 100 MW battery energy storage power station. The power station has the advantages of simple structure, easy coordinated control, low control loop model and coupling, and optimal system stability. The control system of the present invention has fewer hierarchies, a small information transmission delay, and a rapid response speed.