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Jung J.-H.,Korea Electrotechnology Research Institute
IEEE Transactions on Power Electronics | Year: 2013

A bifilar winding method is proposed for the center-tapped transformer which includes integrated resonant inductance in an LLC resonant converter in order to improve the balance of its resonant network and power conversion efficiency. This method can reduce resonance imbalance and transformer inefficiency caused by leakage inductance imbalance in the secondary side of the transformer. As a result, the proposed bifilar winding method employed in the center-tapped transformer maintains the balance of rectifying current and reduces conduction losses in the converter. © 1986-2012 IEEE.


Patent
Korea Electrotechnology Research Institute | Date: 2016-02-24

The invention relates to an electric machine, comprising: a stator (2, 2b, 4) having stator teeth (2a, 4a); and at least two movers moving with respect to the stator, the two movers being spaced apart from each other at intervals corresponding to an electrical phase difference of 60, wherein each of the movers has mover teeth (1a) in multiples of three, with phase coils (1d) formed by coils respectively wound around the mover teeth (1a), the coils are wound around the corresponding mover teeth (1a) such that an electric phase difference between the phase coils (1d) of the adjacent mover teeth (1a) is 120, and at least one protrusion (1c, 4c) is provided on ends of the stator teeth (2a, 4a) or ends of the mover teeth (1a) and at least one permanent magnet (1b, 4b) is provided on each of left and right sides of the protrusion (1c, 4c), or permanent magnets (1b, 4b) are provided on ends of the stator teeth (2a, 4a) or ends of the mover teeth (1a) such that opposite poles thereof alternate with each other (see fig. 1d).


Patent
Korea Electrotechnology Research Institute | Date: 2015-04-01

Provided is a reflection detection type measurement method for skin fluorescence. The method includes: irradiating excitation light on a measurement target; detecting a reflected light and a skin fluorescence generated from the measurement target due to the excitation light; irradiating light with a wavelength range of the skin fluorescence on the measurement target; detecting a reflected light generated from the measurement target due to the light with a wavelength range of the skin fluorescence; and calculating a skin fluorescence value of the measurement target by correcting a calculation based on the detected reflected light and skin fluorescence.


Patent
Korea Electrotechnology Research Institute | Date: 2015-04-01

Provided is a reflection detection type measurement apparatus for skin fluorescence. The apparatus includes: a first light source irradiating excitation light on a measurement target; a second light source irradiating light of a wavelength different from that of light from the first light source on the measurement target; a first optical detector detecting a reflected light generated from the measurement target due to the excitation light of the first light source; and a second optical detector detecting a skin fluorescence generated from the measurement target due to the excitation light of the first light source, and detecting a reflected light generated from the measurement target due to the excitation light of the second light source. The first optical detector is disposed in an area other than a total reflection area to which the excitation light of the first light source is reflected after irradiating to the measurement target.


Patent
Korea Electrotechnology Research Institute | Date: 2016-08-17

Provided is a DC current breaker having a high-speed breaking function appropriate to a voltage-type converter and a DC current breaking method. In addition, provided is a DC current breaker and a DC current breaking method capable of reducing cost of the breaker and securing economical competiveness by using a relatively simple configuration. The DC current breaker for breaking a DC current at the time of occurrence of an accident includes: a main conduction unit including three high-speed mechanical switches installed to be connected in series to a main conduction path for conducting a normal-operation-state current; a power semiconductor switch installed to be connected in parallel to one high-speed mechanical switch among the high-speed mechanical switches installed in the main conduction unit for current breaking of the main conduction unit; a capacitor installed on a circuit connected in parallel to the main conduction path; and a surge arrester installed to be connected in parallel to the capacitor connected in parallel to the main conduction path. The DC current breaking method uses the DC current breaker.


Patent
Korea Electrotechnology Research Institute | Date: 2015-01-07

Provided is a high precision DC/DC resonant converter with a wide load range, including: a first switch leg having one end connected to an anode terminal of a DC power source and the other end connected to a cathode terminal of the DC power source to independently operate at a switching frequency used in an application of an output voltage for no load or a light load equal to or less than a rated load and operate to reduce a ripple of the output voltage at a frequency equal to or less than the switching frequency used in the application of the output voltage for no load or the light load equal to or less than the rated load; and one or more second switch legs having one end connected to the anode terminal of the DC power source and the other end connected to the cathode terminal of the DC power source to operate at a switching frequency for the rated load or a frequency equal to or less than the switching frequency used in the application of the output voltage for no load or the light load that the first switch leg takes charge of. The resonant converter can stably operate with high efficiency even in a light load using a switch leg taking charge of the light load.


Patent
Yonsei University and Korea Electrotechnology Research Institute | Date: 2015-12-10

An inverter-based stand-alone microgrid control system using a PMU, in which a converter controller configured to control a converter that determines a voltage and a phase of a point where a plurality of distributed power supply devices is interconnected. The system includes a time correction unit configured to provide a time corrected on the basis of time information received from a GPS; a signal comparison/generation unit configured to compare a sine wave generated according to a voltage magnitude and a phase reference signal with a harmonic carrier signal on the basis of the time provided by the time correction unit, and generate a PWM signal; and a switch operation control unit configured to apply the PWM signal from the signal comparison/generation unit to the converter, and operate a switch.


Patent
Korea Electrotechnology Research Institute | Date: 2015-12-18

A magnetic resonance wireless power transfer method according to an aspect of the present invention includes transmitting power from a source coil to the Tx resonant coil using a magnetic induction method, transmitting the power from the Tx resonant coil to an Rx resonant coil, having a resonant frequency identical with that of the Tx resonant coil, via magnetically-coupled resonance, and transmitting the power from the Rx resonant coil to the device coil of an electronic device using the magnetic induction method. The Tx resonant coil and the Rx resonant coil are arranged at a right angle or a specific angle of inclination relative to each other.


Patent
Korea Electrotechnology Research Institute | Date: 2015-12-28

The present invention relates to a transmitting device for wireless power transmission, which includes: a bowl-shaped transmitting device body; and a transmitting coil unit for wirelessly transmitting power to a receiving device based on power supplied from a power source. The transmitting coil unit may include a multi-loop coil unit wound in the bottom surface of the transmitting device body, and a helical coil unit wound around the side wall of the transmitting device body, the helical coil unit being wound to increase the radius of a coil loop in a direction to the upper part of the transmitting device body, and being extended from the end of the multi-loop coil unit.


Patent
Korea Electrotechnology Research Institute | Date: 2015-05-06

A transformer including first coil unit and second unit, wherein one or more coils are wound on the bobbin of insulating material in at least one of the first coil unit and the second unit, and wherein the bobbin is formed with at least one partitioning flange for partitioning a coil winding surface of the bobbin into two winding surfaces along the longitudinal direction of the bobbin, is disclosed.

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