Abstract: An apparatus for processing electric power includes a power-converter having a path for power flow between first and second power-converter terminals. During operation the first and second power-converter terminals are maintained at respective first and second voltages. Two regulating-circuits and a switching network are disposed on the path. The first regulating-circuit includes a magnetic-storage element and a first-regulating-circuit terminal. The second regulating-circuit includes a second-regulating-circuit terminal. The first-regulating-circuit terminal is connected to the first switching-network-terminal and the second-regulating-circuit terminal is connected to the second switching-network-terminal. The switching network is transitions between a first switch-configuration and a second switch-configuration. In the first switch-configuration, charge accumulates in the first charge-storage-element at a first rate.

Abstract: A photovoltaic power plant and a secondary frequency modulation control method therefor are disclosed. The photovoltaic power plant includes a photovoltaic power station and an active power control system, wherein the photovoltaic power station includes a photovoltaic array and a photovoltaic inverter, the photovoltaic inverter being used for converting direct-current electric energy generated by the photovoltaic array into alternating-current electric energy; and the active power control system is used for performing power allocation on the photovoltaic inverter based on a power control AGC instruction value when running data of the photovoltaic power plant meets a pre-set secondary frequency modulation condition, and adjusting an active power output from the photovoltaic inverter based on an AGC instruction value of the photovoltaic inverter subjected to power allocation. The photovoltaic power station can improve the accuracy of power control and the stability of a power system.

Abstract: A power management integrated circuit (PMIC) is provided for extracting power from an energy harvester. The PMIC includes a power point tracker configured for defining an optimum operational voltage for efficiently extracting power from any type of energy harvesters such as electromagnetic energy sources, photovoltaic cells or thermal electric generators. The power management integrated circuit (PMIC) also relates to an energy harvesting system that includes an electromagnetic energy source and an impedance connected to the PMIC.

Abstract: Concepts and technologies for video alternate network access points and receivers that enable wireless delivery of video content to multiple customer premises over a service area are provided herein. In an embodiment, a system includes a satellite dish receiver that is configured to receive a satellite video feed, and a video alternate network access point that is communicatively coupled to the satellite dish receiver. The video alternate network access point can perform operations that ingest the satellite video feed directly from the satellite dish receiver. The operations can activate a microcell transceiver embedded within the video alternate network access point, and identify a multicast-broadcast single-frequency network channel. The operations can then transmit, to a video alternate network receiver device from the microcell transceiver, the satellite video feed over at least the multicast-broadcast single-frequency network channel.

Abstract: A power supply apparatus includes converters connected in parallel to a three-phase alternating-current power supply, input current detectors that detect current flowing through the respective three phases of the three-phase alternating-current power supply, and load current detectors that detect load current of the converters. Each of the converters includes AC-DC converters inputs of connected to two of the three phases. The AC-DC converters are connected in parallel to each other using a common output. The AC-DC converters that are driven maintain balance of output current. A controller determines whether switching between a driven state and a stopped state of the respective AC-DC converters is performed based on detection results from the load current detectors and switches between the driven state and the stopped state of the respective multiple AC-DC converters based on detection results by the input current detectors.

Abstract: Disclosed herein are an apparatus for driving converters in a wind power generation system, an apparatus for controlling converters in a wind power generation system, an apparatus for driving switching element modules in a wind power generation system, and an apparatus for controlling switching element modules in a wind power generation system. The apparatus for driving converters in a wind power generation system includes a converter control unit configured to drive a plurality of converters connected in parallel between a generator and a grid, wherein the converter control unit sequentially drives the converters one by one when output power of the grid increases and sequentially stops the operations of the converters one by one when output power of the grid decreases.

Abstract: Disclosed are a photovoltaic air-conditioning system and a photovoltaic air conditioner having same. The photovoltaic air-conditioning system comprises a photovoltaic battery, a switch module, an inverter circuit, a rectification circuit and a compressor inverter; an input end of the switch module is electrically connected to a power grid; a first output end of the switch module is electrically connected to a first input/output end of the inverter circuit; a second output end of the switch module is electrically connected to an input end of the rectification circuit; an output end of the rectification circuit is electrically connected to an input end of the compressor inverter; the input end of the switch module is not simultaneously conducting with both of the first output end and the second output end of the switch module.

Abstract: A voltage converter control apparatus controls repetitive switching operations of a voltage converter, for conversion between a terminal voltage of a battery as an input-side voltage and a terminal voltage of a power inverter as an output-side voltage, by determining a command value of duty ratio of the switching in accordance with a command value of the output-side voltage. The voltage converter control apparatus sets a normal duty ratio range defining limit values of the duty ratio for normal operation of the voltage converter, with the limit values being determined based upon information including the command value of the output-side voltage.

Abstract: A method for operating a transformerless inverter includes operating first and second half-bridges of the inverter using a unipolar clocking method as a first clocking method, determining a value of a grid-frequency stray current at the DC terminals of the inverter during the unipolar clocking method, and when a limit value is exceeded by the stray current value, operating the first and second half-bridges of the inverter using a stray-current-reducing clocking method as a second clocking method in which the first half-bridge provides an AC voltage at the first AC output, wherein an amplitude of the AC voltage is less than 50% of the amplitude of a voltage amplitude of the grid, and the second half-bridge provides a difference voltage between the grid voltage and the voltage provided by the first half-bridge at the first AC output.

Abstract: Disclosed is a method for controlling a solar air conditioner, which includes: a detection step, detecting the change situation of a DC voltage outputted by an inverter of the solar air conditioner when it is detected that the solar air conditioner enters an energy-saving control mode; and a judging step, adjusting an operating frequency of a compressor of the solar air conditioner according to the change situation of the DC voltage, so that the solar air conditioner uses a solar cell to supply power. Thus, solar energy can be used to the maximum degree, the problem that there is a need to supply power by a mains power supply because the power supplied for the solar energy is insufficient is avoided, and the cost is saved. Further a device for controlling the solar air conditioner and the solar air conditioner are provided.

Abstract: A medium voltage direct current (MVDC) collector system for renewable power generation facilities includes at least one renewable energy generation device. The MVDC collector system also includes at least one direct current (DC)-to-DC (DC/DC) power converter coupled to the at least one renewable energy generation device. The at least one DC/DC power converter is configured to shift a switching operation of the DC/DC power converter between full-wave conversion and half-wave conversion. The MVDC collector system further includes at least one controller coupled to the at least one DC/DC power converter. The at least one controller is configured to regulate shifting the switching operation of the at least one DC/DC power converter between full-wave conversion and half-wave conversion.

Abstract: Provided is a method for charging/discharging a battery pack having an auxiliary charging/discharging device and a battery assembly in which a plurality of secondary battery cell parallel modules, each of which includes a plurality of fasecondary battery cells connected in parallel, are connected in series, the method including, when there is no abnormality in the secondary battery cells during charging/discharging, connecting the auxiliary charging/discharging device in parallel to any of the secondary battery cell parallel modules, and when there is an abnormality in any of the secondary battery cells during charging/discharging, releasing connection to the secondary battery cell at which the abnormality has arisen in the secondary battery cell parallel module including the secondary battery cell at which the abnormality has arisen, and connecting the auxiliary charging/discharging device in parallel to the secondary battery cell parallel module including the secondary battery cell at which the abnormality

Abstract: The invention relates to a method for operating a converter in an energy distribution system, wherein, by means of the converter, an electrical energy provided by a source is fed into an AC electricity network at a coupling point (E) or electrical energy is drawn from the AC electricity network at the coupling point (E), wherein the AC electricity network is coupled to further converters for feeding in or drawing electrical energy, wherein the converter has an inverter provided with power switches in order to provide an electrical variable, comprising providing one or a plurality of system state variables indicating a system state of the electricity network, selecting one of a plurality of commutation patterns depending on the one or the plurality of system state variables, and driving the inverter according to the selected commutation pattern.

Abstract: A relay abnormality detection device to detect an abnormality of a grid interconnection relay upon switching to grid independent operation and includes an abnormality detector to execute commercial power system voltage for determining whether or not there is a commercial power system voltage, if there is commercial power system voltage through the commercial power system voltage determination, first current determination of abnormality determination as to the specific relay according to whether or not there is an input current to the power conditioner in a state where a contact of the specific relay is controlled to open, and if there is no commercial power system voltage through commercial power system voltage determination, second current determination of abnormality determination as to the specific relay according to whether or not there is an output current from the power conditioner in the state where the contact of the specific relay is controlled to open.

Abstract: Provided are a photovoltaic system and a method for controlling a photovoltaic system. The photovoltaic system includes a photovoltaic output device, an inverter device, an AC interface device, a control device and an AC load, where a supply terminal of the AC load is connected to an AC output side of the inverter device, and a control terminal of the AC load is connected to the control device, and the method for controlling the photovoltaic system is applied to the control device. The method for controlling the photovoltaic system includes: controlling the AC interface device to maintain the inverter device being disconnected from an electrical grid; starting the inverter device and then starting the AC load; and controlling the AC interface device to connect the inverter device to the electrical grid, in a case that it is determined that a grid connection condition is met for the photovoltaic system.

Abstract: The present invention relates to a method (40) for transmitting electrical power between an energy supply grid (16) and an energy consumer (12) or energy producer (12) which is coupled to the energy supply grid (16), wherein at least one electrical variable of the energy supply grid (16) is detected, wherein a discrepancy between the electrical variable and a rated variable of the energy supply grid (16) which is associated with the electrical variable is determined, wherein the power transmission is controlled on the basis of the discrepancy, and wherein the electrical variable is a mains frequency and/or a mains voltage of the energy supply grid (16) and the rated variable is a rated frequency and/or rated voltage of the energy supply grid (16).

Abstract: There is provided a power supply apparatus for power converters which convert power generated by power generators into power to be supplied to a power system. The power supply apparatus includes a photovoltaic power cell for the power converters, the photovoltaic power cells generating power for supplying power of the power converters.

Abstract: The present invention relates to a controller for a grid tied inverter system with an improved control configuration for increasing response speed of an output current according to specific electric power required. The controller comprises a first control circuit section to output a direct current (DC)-DC converter control signal, and a second control circuit section to output an inverter control signal, wherein the first control circuit section and the second control circuit section are independent of each other without a link for signal input and output therebetween.

Abstract: An automatic equalization method and apparatus for bus bar voltages of a Power Factor Correction (PFC) circuit. The method includes calculating a difference in voltages of a positive bus bar and a negative bus bar, and increasing the rotation speed of a fan in the PFC circuit according to the difference in voltages of the positive bus bar and the negative bus bar until the voltages of the positive and negative bus bars are equalized. The apparatus includes a voltage difference module configured to calculate a difference in voltages of a positive bus bar and a negative bus bar, and a rotation speed control module configured to increase a rotation speed of a fan in the PFC circuit according to the difference in voltages of the positive bus bar and the negative bus bar, until the voltages of the positive and negative bus bars are equalized.

Abstract: A power injection system (5) for delivering electrical power to one or more communications connections in a network, is responsive to a monitor (54) which measures the amplitude of signals present on the line to control an injector (55) such that it delivers a line voltage which, combined with the measured signal amplitude complies with a predetermined limit for the line.

Abstract: An inverting apparatus and an AC power system are provided. The inverting apparatus includes an inverting circuit, a detection circuit, and a control circuit. The inverting circuit receives a DC input voltage and converts the DC input voltage into an AC output voltage. The detection circuit samples the AC output voltage and compares the sampled AC output voltage respectively with a first reference voltage and a second reference voltage so as to generate a first indication signal and a second indication signal. The control circuit controls the operation of the inverting circuit. The control circuit determines whether the amplitude of the AC output voltage is located within an operating voltage range during each driving cycles according to the first and the second indication signals, and decides whether to enable an overvoltage protection or an undervoltage protection to control the power conversion of the inverting circuit according to the determination results.

Abstract: An inverting apparatus and a control method thereof are provided. The inverting apparatus includes an inverting circuit, a detection circuit, and a control circuit. The control circuit is coupled to the inverting circuit and the detection circuit and configured to provide a control signal to control the inverting circuit so as to adjust a voltage value of an input voltage into a command voltage represented by the control signal. The control circuit calculates a voltage difference between the detected input voltage and the command voltage so as to determine whether the voltage difference is greater than a preset value. When determining that the voltage difference is greater than the preset value, the control circuit sets the voltage value of the command voltage as the voltage value of the current input voltage.

Abstract: The invention relates to a system for the electronic management of a photovoltaic generator, said system comprising a plurality of n static converters (11, 12, 13) connected in parallel, each converter (11, 12, 13) being electrically connected to at least one photovoltaic cell (10) of the generator. The number of converters connected is determined by comparing the generated power to thresholds P1, P2, . . . , Pn-1 which are defined as the power values substantially at the point of intersection of the performance curves for an increasing number of converters. The invention also relates to a generator comprising said system and to the associated control method.

Abstract: Systems, methods, and devices for use with photovoltaic micro-inverters. A control system for controlling power switches in a full bridge inverter in a DC/DC converter uses an estimate of the output current of a photovoltaic (PV) panel. The estimate is provided by a current estimator that takes as input the output voltage of the PV panel as well as the bus voltage of the DC/DC converter. Also used as input to the current estimator are two of the control signals for specific power switches in the full bridge inverter in the DC/DC converter.

Abstract: An electric power supply system includes: an AC generator having a drooping characteristic; a rectification section for converting AC output of the AC generator to DC; a load having an electric storage device supplied with power from the AC generator; and a control section provided between the rectification section and the load. The control section controls the AC generator so that the AC generator operates at predetermined voltage lower than output voltage corresponding to the maximum power operation point of the AC generator.

Abstract: A photovoltaic power conditioning system and method is provided. The system includes an isolated DC/DC converter (41), a DC/AC inverter (42), and a sine filter (43). The isolated DC/DC converter (41) receives a DC voltage from a solar cell through a parallel connection structure and converts the DC voltage into another DC voltage and then outputs the converted DC voltage through a series connection structure. The DC/AC inverter (42) converts the DC voltage output from the isolated DC/DC converter into an AC voltage. The sine filter (43) performs sine filtering on the AC voltage output from the DC/AC inverter and outputs the filtered AC voltage. The system employs a topology allowing it to be responsible for part of the output capacity, thereby significantly reducing the required capacity and increasing the system efficiency, so that the system can be applied to small and large-capacity photovoltaic power generation.

Abstract: A solar array system includes at least one solar array and at least one solar array regulator. The solar array regulator has an input port to be connected to the solar array, and an output port to be connected to a power bus. The solar array comprises a switching voltage converter comprising a step-down (PC1) and a step-up (PC2) power cell connected in cascade; and a control circuit for driving said voltage converter in a step-up, a step-down or a direct energy transfer mode, depending on an input control signal and on at least one feedback signal (SILF) indicative of an operating condition of said switching voltage converter; characterized in that said at least one feedback signal (SILF) is indicative of an intensity of an electrical current (IL) flowing between said step-down and said step-up power cells, whereby the control circuit implements an internal current feedback control.

Abstract: The invention describes a solar generation method by means of a system (1) comprising a set of solar cells (2) connected to an inverter (4) that transmits the energy generated to an electrical network (6), which comprises controlling the active and reactive power that the system (1) transmits to the electrical network (6) by controlling the voltage (Vcell) of the cells (2) and the output current (Iinv) of the inverter (4), such that: in a first mode of operation, the voltage (Vcell) of the cells (2) provides the maximum active power in accordance with the operating conditions; and, in a second mode of operation, the voltage (Vcell) in the cells (2) is different from the voltage that provides the maximum active power, generating an active power that is lower than the maximum, in order to optimise the integration of the solar generation system (1) into the electrical network (6).

Abstract: A converter unit configured to couple to a photovoltaic panel (PV) may include a controller to sense an input voltage and input current obtained from the photovoltaic panel, and manage the output voltage of a corresponding power converter coupled to a DC bus to regulate the resultant bus voltage to a point that reduces overall system losses, and removes non-idealities when the panels are series connected. The controller may also perform input voltage management and regulation, including maximum power point tracking (MPPT) for the PV. The controller may probe the bus voltage using a probe waveform generated according to a pseudo-random bit sequence (PRBS), to provide a probe signal that is distinct from the control steps performed by the controller. A PV array may feature a respective converter unit coupled to each PV, with each respective controller using a different and unique seed for generating its PRBS.

Abstract: An output control apparatus of a solar cell is provided with: a first controlling device for sequentially increasing a load for extracting the output from a load in an increase area in which the output increases with respect to an increase in the load; a detecting device for detecting a decrease in the output with respect to the increase in the load in a process of sequentially increasing the load; and a second controlling device for rapidly reducing the load to an initial load which belongs to the increase area in comparison with the process of sequentially increasing the load in cases where a change in the output is detected, the first controlling device sequentially increasing the load again after the load is reduced to the initial load.

Abstract: A system for providing power from solar cells whereby each cell or cell array is allowed to produce its maximum available power and converted by an operatively connected DC/DC converter. Each cell or cell array has its own DC/DC converter. In one form the system includes one or more solar generators wherein each solar generator has one to nine solar cells; a maximum power tracker operatively associated with each solar generator, each maximum power tracker including a buck type DC/DC converter without an output inductor, each maximum power tracker being operatively connected in series with each other; an inductor operatively connected to the series connected maximum power trackers; and means for providing electrical power from the inductor to load means, wherein each maximum power tracker is controlled so that the operatively associated solar generator operates at its maximum power point to extract maximum available power.

Abstract: The plant comprises: a DC-voltage electric power source (3), whose operating conditions vary as a function of at least one uncontrollable quantity, for each value of the uncontrollable quantity the source presenting a characteristic curve of the supplied power as a function of a controlled quantity, wherein each characteristic curve presents a maximum for an optimal value of said controlled quantity; a power conditioning circuit (5); a regulation loop (9) to adjust the controlled quantity maximizing the power supplied by the source when said uncontrollable quantity varies. The regulation loop is de-signed in such a way as to determine whether, for the actual value of said uncontrollable quantity, the actual value of the controlled quantity (V.in) is greater or lower than the optimal value and to generate a regulation signal (V.in-REF) to modify the actual value of the controlled quantity towards the optimal value.

Abstract: Disclosed herein is a solar cell system including: a solar cell; a load controller connected to the solar cell, the load controller being capable of controlling a load applied to the solar cell; an output measuring unit for measuring a power generation output of the solar cell; and an output predicting unit for predicting a value to be reached by the output on a basis of transient response of the output measured by the output measuring unit, wherein the solar cell system has a function of controlling the load controller so as to maximize the value to be reached.

Abstract: In a light power generation system, a control device, a control method, and a program, efficient power can be supplied. The maximum power detection unit operates a MOSFET in a power converter circuit and open-circuits both ends of a solar cell panel in the maximum power detection mode. After that, the maximum power detection unit short-circuits both ends of the solar cell panel, detects a maximum power by monitoring the output power of the solar cell panel during a period from the open state to the short-circuited state, and defines the voltage of the solar cell panel as an optimal voltage when detecting the maximum power. In a tracking operation mode, the control unit performs PWM control with respect to the MOSFET by defining the optimal voltage to be a reference signal. Operations are repeated between the maximum power detection mode and the tracking operation mode.

Abstract: A photovoltaic (PV) control system generates a power output rate control signal based on a monitored rate of change of collective power output generated via a plurality of PV subsystems and a desired collective output power change rate for the plurality of PV subsystems and communicates the power output rate control signal to the plurality of PV subsystems to control a rate of change of one or more operating parameters of individual PV subsystems in order to control a rate of change of collective output power of the plurality of solar PV subsystems.

Abstract: Disclosed here is a grid-interactive photovoltaic generation system having power quality improvement and power saving functions. The grid-interactive photovoltaic generation system includes a solar cell array, a first inverter, and a second inverter. The solar cell array receives solar light and generates predetermined power. The first inverter converts the power, generated by the solar cell array, into power required by a grid line. The second inverter is connected to the first inverter, and steps down power, which will be supplied to a load, to an appropriate voltage.

Abstract: A back sheet comprises an interconnect circuit coupling a plurality of solar cell tiles. A tiled solar cell, comprising a solar cell and encapsulating and glass layers, is inserted into the solar cell tiles. Each solar cell is individually addressable through the use of the interconnect circuit, The interconnect circuit is programmable and allows for dynamic interconnect routing between solar cells. As such, the dynamic interconnect routing may be configured so as to create strings of solar cells such that solar cells with an output specification are matched to solar cells with similar output specifications.

Abstract: A solar cell regulator in a nanosatellite includes a pulse width modulated DC-DC boost converter and a peak power tracking controller for converting solar cell power to bus power for charging of system batteries and powering loads while the controller controls the pulse width modulation operation of the converter for sensing solar cell currents and voltages along a power characteristic curve of the solar cell for peak power tracking, for determining any power data point, including a peak power point, an open circuit voltage point, and a short circuit current point along the power characteristic curve of the solar cell, and for communicating the power data to a satellite processor for monitoring the performance of the solar cell during operational use of the satellite.

Abstract: A method and system for managing computational workload in a computerized system powered by an energy source. This invention relies first and foremost on adapting computational workload at the computerized system according to a time-varying property of the power supplied by the energy source, such that power generated at the source is optimized. A feedback mechanism is accordingly implemented which changes power available for computation, e.g., to track a more efficient energy generation efficiency point at the source.

Abstract: A control circuit controls a power output module and drives a load device. The control circuit includes a conversion unit, a feed-forward unit, a feedback unit and a control unit. The conversion unit generates a driving signal according to an output signal of the power output module for driving the load device. The feed-forward unit generates a duty cycle reference signal according to the output signal. The feedback unit generates a feedback signal according to the driving signal. The control unit outputs a control signal to control the conversion unit according to the duty cycle reference signal and feedback signal, thereby limiting the output power of the power output module within the maximum power region. A tracking method of the maximum power is also disclosed.

Abstract: An analog controller is disclosed. The controller has a maximum power point tracking unit and a power factor adjusting unit. The maximum power point tracking unit generates a maximum power tracking voltage which is used to control the magnitude of the output current of the inverter so as to extract the most available power from the power generating device. The power factor adjusting unit, which generates a ramp control voltage that will further determine the duty ratio and switching frequency of PWM signal, gracefully tunes the magnitude and reduces the total harmonic distortion of the current injected from inverter into utility grid.

Abstract: An electric generating system using a solar cell improves the quality of output power by including a converter for converting an output voltage generated from the solar cell into DC voltage in a pulse shape. An inverter converts the DC voltage in the pulse shape into an AC voltage and applies the AC voltage to a power system and a control device for determining whether an erroneous operation of the electric generating system using the solar cell is generated or not based on an output voltage of the solar cell, an output current of the solar cell and a voltage of the power system. At least one inverter switching device among a plurality of inverter switching devices performs a switching at a frequency higher than a frequency during a normal operation at an interval where the erroneous operation is generated.

Abstract: An apparatus for tracking a maximum power point includes a converter unit for converting a first power, outputted from a solar cell module, into a second power and a maximum power point control unit for searching for a maximum power point voltage and an open-circuit voltage corresponding to a temperature and solar radiation of the solar cell module, decreasing voltage of the first power from the open-circuit voltage to the maximum power point voltage in a soft-start manner, and then performing Maximum Power Point Tracking (MPPT) control according to a Perturbation and Observation (P&O) algorithm.

Abstract: A portable self-contained photovoltaic device is provided with a hollow cylindrical support in two substantially coaxial portions assembled to one another. The device further includes a rolled flexible photovoltaic collector and a battery mounted in the first portion of the coaxial portions and designed to store electric energy produced by the photovoltaic collector. An electronic control circuit is mounted in the first portion for managing the charging of the battery. Several LED lamps are stored inside the photovoltaic collector and placed inside the second portion of the coaxial portions.

Abstract: A DC/DC converter includes two input terminals for a DC input voltage, two output terminals for a DC output voltage, an inverter converting a DC voltage into an AC voltage, and a rectifier converting an AC voltage from the inverter into a DC voltage between a first one of the input terminals and a first one of the output terminals. At least one galvanically isolating element is arranged between the output of the inverter and the input of the rectifier, and a capacitance is coupled between the output terminals. The inverter converts a partial DC voltage, being smaller than the full DC input voltage, across a capacitance between the second one of the input terminals and the second one of the output terminals.

Abstract: A maximum power point tracking method is provided. The method includes temporarily determining a next voltage command using voltage and power measured at current and previous time points. When an increase or decrease in voltage command is continued predetermined times or more, it is decided that the next voltage command temporarily determined to be increased is decreased or that the next voltage command temporarily determined to be decreased is increased. The output voltage of a solar cell is regulated based on the decided next voltage command.

Abstract: A power control method for tracking a Maximum Power Point (MPP) in a photovoltaic system including a solar cell and a boost converter. The power control method includes finding the MPP by applying a continuous ON/OFF signal to the boost converter as a first control signal for controlling a duty ratio of the boost converter, and maintaining an operating point of the photovoltaic system at the MPP by applying a second control signal for controlling the duty ratio to the boost converter depending on a constant-voltage command. In tracking an MPP in a photovoltaic system, an MPPT algorithm may remain at the MPP, without self oscillation, improving fast dynamic characteristics upon a change in solar radiation.

Abstract: The invention relates to a process of connecting an AC output of a transformerless inverter of a solar power plant to an internal AC power grid at an input side of a galvanic isolation, while an offset voltage for shifting a potential center point of a photovoltaic generator connected to the inverter is applied. The process includes: (i) synchronizing the inverter with the power grid; (ii) essentially matching a potential center point of the current-carrying lines of the AC output and a potential center point of the power grid, while only one of the potential center points of the current-carrying lines and the power grid is yet shifted by the offset voltage; and (iii) galvanically connecting all current-carrying lines of the AC output with the power grid only after the steps of synchronizing and essentially matching.

Abstract: A maximum-power-point tracking device is provided for a solar electric-generation system that includes a solar battery and a DC/DC converter connected to the solar battery. The device includes a sampling module configured to detect output current and voltage values of the solar battery. A controlling module is configured to calculate a target current value according to the output current and voltage values and a preset current value, and output a controlling signal for controlling the value of a current according to the output current of the solar battery and the target current value. The device also includes a driving module configured to receive the controlling signal from the controlling module and output a driving signal to adjust a output current value of the DC/DC converter to close to the target current value and adjust an output power of the DC/DC converter.

Abstract: A power conversion system configured to provide alternating current (AC) power to a transformer is described. The power conversion system includes a power conversion device that includes a device input and a device output. The power conversion device is configured to receive power from a power source at the device input and the device output is configured for coupling to a transformer input. The power conversion system also includes a sensor coupled at a first point of interconnection between the device output and the transformer input and is configured to measure a voltage level at the first point of interconnection. The power conversion system also includes a system controller communicatively coupled to the power conversion device and the sensor. The system controller is configured to determine an impedance of the power grid based at least partially on the voltage level at the first point of interconnection.