Abstract: A plug for a DC appliance includes an input unit including anode and cathode terminals, an output unit including anode and cathode terminals to allow a DC current input through the input unit to be output to an electric device, a connection unit to interconnect the input unit and the output unit, a rectifier unit coupled between anode and cathode terminals of the input unit to rectify the input DC current, an inductor unit connected in series to the rectifier unit so that an internal current of the plug is gradually increased in response to an increase of the input DC current, and a condenser unit connected in series to the inductor unit, which is charged with voltage in response to a current passing through the inductor unit, and discharges the charged voltage to the output unit when the input of the DC current from the input unit is interrupted.

Abstract: A charging device according to an exemplary embodiment of the present invention may include: a battery adapted and configured to store a DC voltage, first and second motors adapted and configured to operate as a motor or a generator, first and second inverters adapted and configured to operate the first and second motors, a voltage transformer adapted and configured to boost the DC voltage of the battery to supply it to the first and second inverters and boosts the DC voltage of the inverter to supply it to the battery, and a charging controller adapted and configured to operate the first and second inverters as a booster or operate the voltage transformer as a buck booster according to a voltage that is input through a neutral point of the first and second motors and the voltage of the battery.

Abstract: A direct current (DC) power supply apparatus includes an input unit configured to receive an outside DC power; a plurality of polarity correction units configured to correct the polarity of the outside DC power; a plurality of switch units installed to correspond to each of the plurality of polarity correction units; a detection unit configured to detect a flow of current of the plurality of polarity correction unit; and a control unit configured to determine a polarity correction unit, at which current of DC power flows, among the plurality of correction units based on a detection signal of transmitted from the detection unit, and control the switch unit corresponding to the determined polarity correction unit at an ON position such that the current of DC power flows through the switch unit which is controlled at the ON position.

Abstract: Disclosed are a maximum power point tracker, a power conversion controller, a power conversion device having an insulating structure, and a method for tracking maximum power point. The power conversion device includes: a DC/AC converter including a primary DC chopper unit having a primary switch, a transformer, and an AC/AC conversion unit including a secondary switch; a current detector detecting current from an input stage of the DC/AC converter and providing a detected current value; a voltage detector detecting a system voltage from an output stage of the DC/AC converter; and a power conversion controller generating a primary PWM signal to be provided to the primary DC chopper unit and secondary first and second PWM signals, having the mutually opposing phases, to be provided to the AC/AC conversion unit by using the detected current value and the system voltage.

Abstract: There is provided an apparatus for the anti-islanding of a power conditioning system. The apparatus for the anti-islanding of a power conditioning system according to the present invention is applied to a power conditioning system including a DC/DC converter and a DC/AC inverter in order to transfer power from a solar cell array to a grid. The apparatus for the anti-islanding of a power conditioning system may include an injection signal generator generating an injection signal, an adder generating a final fundamental wave command value, a main controller performing the power control according to the final fundamental wave command value and stopping the operation of the power conditioning system when the level of the detected injection signal has reached the predetermined reference level or more, and an injection signal detector detecting the injection signal included in voltage and providing them to the main controller.

Abstract: There are disclosed a photovoltaic and fuel cell (PV-FC) hybrid generation system using a single converter and a single inverter, and a method of controlling the same. The PV-FC hybrid generation system includes a DC/DC converter unit converting an FC output voltage from a fuel cell, converting chemical energy into electrical energy, into a preset voltage, a DC link unit commonly connecting an output terminal of a photovoltaic cell, converting the sunlight into electrical energy, and an output terminal of the DC/DC converter unit, and linking the converted FC output voltage from the DC/DC converter unit with a PV output voltage from the photovoltaic cell to thereby generate a DC voltage, and a DC/AC inverter unit converting the DC voltage from the DC link unit into a preset AC voltage. Furthermore, a method of controlling the PV-FC hybrid generation system is proposed.

Abstract: There is provided an apparatus and method for controlling a switch of a flyback converter for a solar generating system. The apparatus for controlling a switch of a flyback converter for a solar generating system includes: an MPPT controller generating a current command value for a maximum power point tracker of a solar cell module, based on input voltage, input current, and output voltage of the flyback converter; a current controller generating a current control signal for tracking the current command value; an output current command value generator generating the phase and magnitude command value of the output current, based on the phase of the output voltage and the current control signal; and a switch controller controlling the main switch of the flyback converter, based on the phase and magnitude command value of the output current, thereby simplifying a circuit while solving disadvantages of a discontinuous conduction mode and a boundary conduction mode.

Abstract: There are provided an apparatus and method for charging and discharging a photovoltaic PCS integrated battery applied to a system that includes a first DC/DC converter 110 connected to a solar cell 10, a DC/AC inverter 120, a DC link unit 130 connected in common to output terminals of the first DC/DC converter 110 and the DC/AC inverter 120, and a second DC/DC converter 140 having a bidirectional DC/DC conversion function connected between the DC rink unit 130 and the battery 30. The present invention calculates the amount of photovoltaic power produced by the solar cell 10 based on voltage and current detected in the voltage/current detector 200, determines one of predetermined control modes according to the amount of photovoltaic power and the connection or not of the battery, and controls the first DC/DC converter 110, the second DC/DC converter, and the DC/AC inverter according to the determined control mode.

Abstract: A charging device according to an exemplary embodiment of the present invention may include: a battery adapted and configured to store a DC voltage, first and second motors adapted and configured to operate as a motor or a generator, first and second inverters adapted and configured to operate the first and second motors, a voltage transformer adapted and configured to boost the DC voltage of the battery to supply it to the first and second inverters and boosts the DC voltage of the inverter to supply it to the battery, and a charging controller adapted and configured to operate the first and second inverters as a booster or operate the voltage transformer as a buck booster according to a voltage that is input through a neutral point of the first and second motors and the voltage of the battery.

Abstract: Disclosed are a maximum power point tracker, a power conversion controller, a power conversion device having an insulating structure, and a method for tracking maximum power point. The power conversion device includes: a DC/AC converter including a primary DC chopper unit having a primary switch, a transformer, and an AC/AC conversion unit including a secondary switch; a current detector detecting current from an input stage of the DC/AC converter and providing a detected current value; a voltage detector detecting a system voltage from an output stage of the DC/AC converter; and a power conversion controller generating a primary PWM signal to be provided to the primary DC chopper unit and secondary first and second PWM signals, having the mutually opposing phases, to be provided to the AC/AC conversion unit by using the detected current value and the system voltage.

Abstract: There are provided an apparatus and a method for controlling the power quality of a power generation system. According to the present invention, there is provided an apparatus for controlling the power quality of a power generation system including a DC/AC inverter converting DC voltage into AC voltage and supplying inverter current to a grid, including: a grid voltage phase follower generating a grid signal; a fundamental extractor extracting a magnitude of a fundamental wave of a load current introduced into a non-linear load connected between the DC/AC inverter and the grid; a first calculator subtracting a preset current compensation value from the magnitude of the fundamental wave from the fundamental extractor; and a second calculator generating an inverter current instruction value for the DC/AC inverter by using the output value of the first calculator and the grid signal and the load current from the grid voltage phase follower.

Abstract: There is provided an integrated control method for eliminating a low frequency ripple in a power conversion system for a fuel cell, more particularly, a control method of a power conversion system capable of eliminating a low frequency ripple, controlling a DC link voltage, and controlling an output power and a system using the same control method. A power conversion system (PCS) that converts an output of a DC power supply received from an external power supply includes a converter that converts a voltage of the input power supply; an inverter that converts an output voltage of the converter into an AC voltage; and a converter control module that outputs a PWM signal for controlling a switch of the converter, and after receiving a power instruction value, the converter control module generates the PWM signal for controlling the converter based on the power instruction value.

Abstract: There is provided a photovoltaic and fuel cell hybrid generation system using dual converters and a single inverter and a method of controlling the same. A photovoltaic and fuel cell (PV-FC) hybrid generation system according to an aspect of the invention may include: a PV DC/DC converter unit converting a PV output voltage into a predetermined voltage; an FC DC/DC converter unit converting an FC output voltage into a predetermined voltage; a DC link unit commonly connecting an output terminal of the PV DC/DC converter unit and an output terminal of the FC DC/DC converter unit, and linking the converted PV output voltage from the PV DC/DC converter unit to the converted FC output voltage from the FC DC/DC converter unit to thereby generate a DC voltage; and a DC/AC inverter unit converting the DC voltage from the DC link unit into a predetermined AC voltage.

Abstract: A plug for a DC appliance includes an input unit including anode and cathode terminals, an output unit including anode and cathode terminals to allow a DC current input through the input unit to be output to an electric device, a connection unit to interconnect the input unit and the output unit, a rectifier unit coupled between anode and cathode terminals of the input unit to rectify the input DC current, an inductor unit connected in series to the rectifier unit so that an internal current of the plug is gradually increased in response to an increase of the input DC current, and a condenser unit connected in series to the inductor unit, which is charged with voltage in response to a current passing through the inductor unit, and discharges the charged voltage to the output unit when the input of the DC current from the input unit is interrupted.

Abstract: A method for selecting the optimum number of phases for a converter is provided, which selects a duty range using an input voltage and an output voltage, obtains ripple values for multiple phases in the duty range, and selects the optimum number of phases using the corresponding ripple values. The method for selecting the optimum number of phases for a converter includes a duty range selection step of selecting a duty range using an input voltage and an output voltage, a ripple value calculation step of obtaining ripple values for multiple phases within the selected duty range, a range ripple selection step of selecting one or more phases in the duty range, and a rated ripple selection step of selecting the phases having the minimum ripple value in a rated duty among the phases selected in the range ripple selection step.

Abstract: There is provided an apparatus and method for controlling a switch of a flyback converter for a solar generating system. The apparatus for controlling a switch of a flyback converter for a solar generating system includes: an MPPT controller generating a current command value for a maximum power point tracker of a solar cell module, based on input voltage, input current, and output voltage of the flyback converter; a current controller generating a current control signal for tracking the current command value; an output current command value generator generating the phase and magnitude command value of the output current, based on the phase of the output voltage and the current control signal; and a switch controller controlling the main switch of the flyback converter, based on the phase and magnitude command value of the output current, thereby simplifying a circuit while solving disadvantages of a discontinuous conduction mode and a boundary conduction mode.

Abstract: There is provided an apparatus for the anti-islanding of a power conditioning system. The apparatus for the anti-islanding of a power conditioning system according to the present invention is applied to a power conditioning system including a DC/DC converter and a DC/AC inverter in order to transfer power from a solar cell array to a grid. The apparatus for the anti-islanding of a power conditioning system may include an injection signal generator generating an injection signal, an adder generating a final fundamental wave command value, a main controller performing the power control according to the final fundamental wave command value and stopping the operation of the power conditioning system when the level of the detected injection signal has reached the predetermined reference level or more, and an injection signal detector detecting the injection signal included in voltage and providing them to the main controller.

Abstract: There are provided an apparatus and method for charging and discharging a photovoltaic PCS integrated battery applied to a system that includes a first DC/DC converter 110 connected to a solar cell 10, a DC/AC inverter 120, a DC link unit 130 connected in common to output terminals of the first DC/DC converter 110 and the DC/AC inverter 120, and a second DC/DC converter 140 having a bidirectional DC/DC conversion function connected between the DC rink unit 130 and the battery 30. The present invention calculates the amount of photovoltaic power produced by the solar cell 10 based on voltage and current detected in the voltage/current detector 200, determines one of predetermined control modes according to the amount of photovoltaic power and the connection or not of the battery, and controls the first DC/DC converter 110, the second DC/DC converter, and the DC/AC inverter according to the determined control mode.

Abstract: There are provided an apparatus and a method for controlling the power quality of a power generation system. According to the present invention, there is provided an apparatus for controlling the power quality of a power generation system including a DC/AC inverter converting DC voltage into AC voltage and supplying inverter current to a grid, including: a grid voltage phase follower generating a grid signal; a fundamental extractor extracting a magnitude of a fundamental wave of a load current introduced into a non-linear load connected between the DC/AC inverter and the grid; a first calculator subtracting a preset current compensation value from the magnitude of the fundamental wave from the fundamental extractor; and a second calculator generating an inverter current instruction value for the DC/AC inverter by using the output value of the first calculator and the grid signal and the load current from the grid voltage phase follower.

Abstract: Disclosed are a maximum power point tracker, a power conversion controller, a power conversion device having an insulating structure, and a method for tracking maximum power point. The power conversion device includes: a DC/AC converter including a primary DC chopper unit having a primary switch, a transformer, and an AC/AC conversion unit including a secondary switch; a current detector detecting current from an input stage of the DC/AC converter and providing a detected current value; a voltage detector detecting a system voltage from an output stage of the DC/AC converter; and a power conversion controller generating a primary PWM signal to be provided to the primary DC chopper unit and secondary first and second PWM signals, having the mutually opposing phases, to be provided to the AC/AC conversion unit by using the detected current value and the system voltage.