Abstract: Provided are a three-phase coaxial superconducting power cable and a structure thereof. A certain space is formed between adjacent superconducting wires of a superconducting layer (disposed at an outer portion) having more superconducting wires among a plurality of superconducting layers, and another wire is disposed in the space, or the superconducting wires of the respective superconducting layers are disposed to have different critical currents. Accordingly, a waste of superconducting wires is prevented, and the optimized three-phase coaxial superconducting power cable is provided.

Abstract: The present invention relates to an apparatus and method for measuring the critical current of a superconducting tape. A continuous critical current measurement apparatus for measuring critical current of a superconducting tape while feeding a superconducting tape in a liquid nitrogen container includes wheel-type current terminals and wheel-type voltage terminals. The superconducting tape is continuously supplied and fed by a reel-to-reel device, and the critical current of the superconducting tape is measured in real time using the wheel-type current terminals and the wheel-type voltage terminals while the superconducting tape is fed at constant linear velocity in contact with the wheel-type current terminals and the wheel-type voltage terminals.

Abstract: The present invention relates to a senseless MPPT control apparatus of a photovoltaic power generation system and a method thereof. The control apparatus includes a current transformer, an A/D converter, a new and old current detector, a new duty ratio detector, an old duty ratio detector, a new and old duty ratio comparator, first and second new and old current comparators, a duty ratio adder, a duty ratio subtractor and a PWM signal generator. A maximum output point of a solar battery cell is tracked by using only one feedback current flowing into a load. Further, feedback factors can be reduced to one. It is possible to simplify the construction of a control circuit and minimize tracking control failure.

Abstract: The present invention relates to an apparatus and method for measuring the critical current of a superconducting tape. A continuous critical current measurement apparatus for measuring critical current of a superconducting tape while feeding a superconducting tape in a liquid nitrogen container includes wheel-type current terminals and wheel-type voltage terminals. The superconducting tape is continuously supplied and fed by a reel-to-reel device, and the critical current of the superconducting tape is measured in real time using the wheel-type current terminals and the wheel-type voltage terminals while the superconducting tape is fed at constant linear velocity in contact with the wheel-type current terminals and the wheel-type voltage terminals.

Abstract: A control apparatus of a single-phase power converter for a photovoltaic power generation system is disclosed, including a POS MPPT controller for calculating a rating current by applying a POS MPPT control method to an output current detected through a current transformer of a single-phase AC filter, a bandpass filter for filtering only signals of a low-frequency band from a load, a single-phase reference current generator for producing a reference current by matching a phase of the current from the POS MPPT controller to a phase from the bandpass filter, a single-phase current subtractor for subtracting an output current of a current transformer from the reference current calculated by the single-phase reference current generator to thereby calculate a difference current between the output current of the current transformer and the reference current, a PI controller for outputting a control signal, corresponding to the difference current from the single-phase current subtractor, to a PWM signal generator, a

Abstract: A control apparatus of a single-phase power converter for a photovoltaic power generation system is disclosed, including a POS MPPT controller for calculating a rating current by applying a POS MPPT control method to an output current detected through a current transformer of a single-phase AC filter, a bandpass filter for filtering only signals of a low-frequency band from a load, a single-phase reference current generator for producing a reference current by matching a phase of the current from the POS MPPT controller to a phase from the bandpass filter, a single-phase current subtractor for subtracting an output current of a current transformer from the reference current calculated by the single-phase reference current generator to thereby calculate a difference current between the output current of the current transformer and the reference current, a PI controller for outputting a control signal, corresponding to the difference current from the single-phase current subtractor, to a PWM signal generator, a

Abstract: The present invention relates to a senseless MPPT control apparatus of a photovoltaic power generation system and a method thereof. The control apparatus includes a current transformer, an A/D converter, a new and old current detector, a new duty ratio detector, an old duty ratio detector, a new and old duty ratio comparator, first and second new and old current comparators, a duty ratio adder, a duty ratio subtractor and a PWM signal generator. A maximum output point of a solar battery cell is tracked by using only one feedback current flowing into a load. Further, feedback factors can be reduced to one. It is possible to simplify the construction of a control circuit and minimize tracking control failure.