Abstract: A wireless power transmission apparatus includes: an alternating current (AC) power output to convert input power into AC power and output the AC power; and a power transmitter including a plurality of resonators. The power transmitter receives the AC power and wirelessly transmits the AC power in a first operating mode in which two of the resonators are connected in series and the two resonators transmit the AC power, and in a second operating mode in which one of the resonators transmits the AC power.

Abstract: A wireless power transmission apparatus includes: an alternating current (AC) power output to convert input power into AC power and output the AC power; and a power transmitter including a plurality of resonators. The power transmitter receives the AC power and wirelessly transmits the AC power in a first operating mode in which two of the resonators are connected in series and the two resonators transmit the AC power, and in a second operating mode in which one of the resonators transmits the AC power.

Abstract: A wireless power transmitter includes: a case; a power transmission coil disposed in the case and configured to wirelessly transmit power; and a coupling antenna coil disposed in the case, wherein an outer diameter of the coupling antenna coil is greater than an outer diameter of the power transmission coil.

Abstract: There is provided an even-level inverter, including: a voltage-dividing circuit dividing input DC power into an even number of voltage levels; a plurality of switching devices connected to individual nodes of the voltage-dividing circuit having the even number of voltage levels; and a bidirectional switching device connected to the individual nodes of the voltage-dividing circuit through at least one of the plurality of switching devices and including at least two transistors. According to the present invention, the bidirectional switching device is implemented without a diode to thereby reduce conduction loss caused due to an anti-parallel diode included in the related art bidirectional switching device, and a neutral point of the voltage-dividing circuit is electrically separated from the switching devices to thereby control reactive power.

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: Disclosed herein is an electric generating system using a solar cell, including: a DC/DC converter that converts output voltage generated from a solar cell into DC voltage and has a converter switching device; a snubber device that has a snubber switch clamping voltage applied to the converter switching device; and a control device that detects the voltage applied to the converter switching device and controls an operation of the snubber switch according to a detected voltage level applied to the converter switching device, thereby increasing the efficiency of the electric generating system using a solar cell while reducing switching loss and conduction loss.

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 a DC-AC power converting apparatus including no capacitor or a small capacity capacitor for removing a ripple in an input terminal thereof by charging or discharging power according to a difference between output power and instantaneous system power of a photovoltaic cell, and a solar power supplying apparatus including the same, the DC-AC power converting apparatus including a DC-AC power converting unit converting DC power into AC power, and a charging and discharging unit charging surplus power induced when a level of the DC power is higher than that of the AC power and discharging the charged power when the level of the DC power is lower than that of the AC power.

Abstract: There are provided a multi-level converter capable of outputting power having various voltage levels with respect to a single input power supply by using a simple circuit, an inverter having the same, and a solar power supply apparatus having the same. The multi-level converter includes a first buck-boost unit having a first power switch switching an input power supply and outputting a first power having a voltage level varied according to switching of the first power switch; a bypass unit outputting a second power having a voltage level of the input power supply; and a second buck-boost unit having a second power switch switching the input power supply and outputting a third power having a voltage level varied according to switching of the second power switch.

Abstract: There is provided a multi-level converter capable of a multi-level converter capable of outputting power having various voltage levels by using a simple circuit with respect to a single input power supply, an inverter having the same, and a solar power supply apparatus having the same. The present invention provides a multi-level converter including a first buck-boost unit having a single power switch switching an input power supply and outputting a first power having a voltage level varied according to the switching of the power switch, a bypass unit outputting a second power having a voltage level of the input power supply, and a second buck-boost unit sharing the power switch with the first buck-boost unit and outputting a third power having a voltage level varied according to the switching of the power switch; an inverter having the same; and a solar power supply apparatus having the same.

Abstract: There are provided a power converting apparatus and an operating method thereof, and a solar power generation system. The power converting apparatus for a solar power generation system includes: a power converting unit converting an input signal generated by a solar cell module into an output signal; and a control circuit unit controlling an operation of the power converting unit, wherein the power converting unit includes at least one transformer, and a current sensor and a switching circuit connected to a primary winding of the at least one transformer, and the control circuit unit calculates a voltage and a current of the input signal using a current of the primary winding of the at least one transformer sensed by the current sensor and performs a maximum power point tracking (MPPT) control so that the power converting unit is operated at a maximum power point.

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 a method and an apparatus for generating a current command value for tracking the maximum power point of a solar energy generating system. The apparatus includes: a voltage detector detecting a voltage input into the flyback power converter; a first calculator calculating an output power from the detected input voltage; a second calculator calculating a power variation based on the calculated output power and a voltage variation of the input voltage; and a current command value generator generating a current command value for tracking the maximum power point of the solar cell module from the calculated voltage variation and the calculated power variation. Accordingly, a current command value after calculating an output power may be generated with only a voltage detector, without a current detector, thereby reducing the costs of a solar energy generating system by decreasing the costs for a high-priced current detector, and simplifying circuit.

Abstract: The present invention provides a switching device and a method for preventing malfunction of the same. The switching device includes: a controller for outputting a plurality of digital control signals; a protecting unit connected to the controller for protecting all signals when the plurality of digital control signals outputted from the controller are simultaneously received at a state of ON; a gate driver connected to the protecting unit for generating a switch control signal by converting the control signal passed through the protecting unit; and a plurality of switches connected to the gate driver for individually performing ON•OFF operations according to each of the switching control signals.

Abstract: There is provided an even-level inverter, including: a voltage-dividing circuit dividing input DC power into an even number of voltage levels; a plurality of switching devices connected to individual nodes of the voltage-dividing circuit having the even number of voltage levels; and a bidirectional switching device connected to the individual nodes of the voltage-dividing circuit through at least one of the plurality of switching devices and including at least two transistors. According to the present invention, the bidirectional switching device is implemented without a diode to thereby reduce conduction loss caused due to an anti-parallel diode included in the related art bidirectional switching device, and a neutral point of the voltage-dividing circuit is electrically separated from the switching devices to thereby control reactive power.

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: 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 a 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: Disclosed herein is an electric generating system using a solar cell, including: a DC/DC converter that converts output voltage generated from a solar cell into DC voltage and has a converter switching device; a snubber device that has a snubber switch clamping voltage applied to the converter switching device; and a control device that detects the voltage applied to the converter switching device and controls an operation of the snubber switch according to a detected voltage level applied to the converter switching device, thereby increasing the efficiency of the electric generating system using a solar cell while reducing switching loss and conduction loss.

Abstract: There are provided a method and an apparatus for generating a current command value for tracking the maximum power point of a solar energy generating system. The apparatus includes: a voltage detector detecting a voltage input into the flyback power converter; a first calculator calculating an output power from the detected input voltage; a second calculator calculating a power variation based on the calculated output power and a voltage variation of the input voltage; and a current command value generator generating a current command value for tracking the maximum power point of the solar cell module from the calculated voltage variation and the calculated power variation. Accordingly, a current command value after calculating an output power may be generated with only a voltage detector, without a current detector, thereby reducing the costs of a solar energy generating system by decreasing the costs for a high-priced current detector, and simplifying circuit.

Abstract: The present invention provides a switching device and a method for preventing malfunction of the same. The switching device includes: a controller for outputting a plurality of digital control signals; a protecting unit connected to the controller for protecting all signals when the plurality of digital control signals outputted from the controller are simultaneously received at a state of ON; a gate driver connected to the protecting unit for generating a switch control signal by converting the control signal passed through the protecting unit; and a plurality of switches connected to the gate driver for individually performing ON•OFF operations according to each of the switching control signals.