• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.6
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• pp.496-503
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• 2017

This study proposes a high-performance current control algorithm for a diode-bridge-type single-phase boost power factor correction (PFC) converter. The conventional asynchronous single-phase current controllers that directly control AC-type current tend to be accompanied by steady-state errors due to their poor dynamic characteristics for the transient-state, which can be attributed to bandwidth limitations and phase delays. In the proposed algorithm, an ideal current control with minimal phase delays and steady-state errors can be achieved by using a virtual DQ synchronous reference frame and by controlling the synchronous reference frame excluding the frequency component in the single-phase system. The performance of the conventional asynchronous single-phase current controller is compared with that of the proposed algorithm through simulation and experiments, and the results have confirmed the superiority of the latter.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.7
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• pp.335-342
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• 2005

This paper presents a circuit to generate the current reference signal for single-phase harmonic elemination systems. Some of conventional methods for the current reference signal generation based on neural network algorithms. It requires complex circuitry to implement. the simplest method is to use analog filters. but it is difficult to obtain good current reference signals. So, we propose the harmonic detection circuit using GIC(Generalized Impedance Converter) for the purpose of low cost ,simple circuitry and high performance, Simulation and experimental results verify that the proposed circuit has better harmonic detection performance than conventional circuit.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.5
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• pp.249-257
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• 2002

In this paper, a novel control scheme compensating source voltage unbalance and harmonic currents for the combined system of series active and shunt passive power filter is proposed, where no low/high-pass filters are used in deriving the reference voltage for compensation. The phase angle and the reference voltages compensating for harmonic current and unbalanced voltage are derived from the positive sequence component of the unbalanced voltage set, which is simply obtained by using digital all-pass filters. In order to remove the phase delay in generating the reference voltage for compensation, the reference of 5th and 7th harmonic components is predicted one-sampling ahead. The validity of the proposed scheme has been verified for 3[kVA] proto-type active power filter system.

• Journal of Power Electronics
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• v.13 no.4
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• pp.692-700
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• 2013

This paper discusses the design of a novel synchronous reference frame (SRF) method that can extract the reference compensating current for single-phase shunt active power filters (APFs). Unlike previous SRF studies, the proposed method has an innovative feature that does not require a fictitious current signal. Other key features of the proposed strategy include frequency-independent operation, accurate reference current extraction, and relatively fast transient response. The effectiveness of the proposed method is investigated by conducting a detailed mathematical analysis. Results of the analysis confirm the superior performance of the suggested approach. Theoretical evaluations are confirmed by the experimental results.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.8
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• pp.377-386
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• 2005

This paper presents the control algorithm of single-phase hybrid active power filter for the compensation of harmonic current components in nonlinear R-L load with passive active Power filters. To construct two phase system, an imaginary second phase was made. In this proposed method, the new signal which is the delayed through the filtering by the phase-delay property of low-pass filter is used as the secondary phase. Because two-phases have the different phase, the instantaneous calculation of harmonic current is possible. In this paper, a reference voltage is created by multiplying the coefficient k by the compensation current using the rotating reference frame synchronized with the source-frequency, not applying to instantaneous reactive power theory which has been used with the existing fixed reference frames In order to verify the validities of the proposed control methods, experiments are carried out with the prototypes of single-phase hybrid active power filter.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.3
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• pp.135-144
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• 2003

This work proposes on-chip full CMOS current and voltage references for high-speed mixed-mode circuits. The proposed current reference circuit uses a digital-domain calibration method instead of a conventional analog calibration to obtain accurate current values. The proposed voltage reference employs internal reference voltage drivers to minimize the high-frequency noise from the output stages of high-speed mixed-mode circuits. The reference voltage drivers adopt low power op amps and small- sized on-chip capacitors for low power consumption and small chip area. The proposed references are designed, laid out, and fabricated in a 0.18 um n-well CMOS process and the active chip area is 250 um x 200 um. The measured results show the reference circuits have the power supply variation of 2.59 %/V and the temperature coefficient of 48 ppm/$^{\circ}C$ E.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.2
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• pp.112-119
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• 2009

This paper presents a PLL(Phase Lock Loop) approach for effective speed and torque control of high speed miniature BLDCM(Brushless DC Motor) using hall sensor. The proposed speed control method based on PLL uses only a phase shift between reference pulse signal according to speed reference and actual pulse signal from hall sensor. It doesn't use any speed calculation, and calculates a direct current reference from phase shift. The current reference is changed to reduce the phase shift between reference and actual pulse. So the actual speed can keep the reference speed. The proposed control scheme is very simple but effective speed control is possible. In order to obtain a smooth torque production, the reference current is changed using acceleration and deceleration slope. The proposed control scheme is verified by experimental results of the 50W, 40,000[rpm] high speed miniature BLDCM.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.312-313
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• 2015

For the traceability of high current measuring sensors of high power testing department II(HPTD II) in Korea Electrotechnology Research Institute(KERI), additional comparison tests with reference test object were performed repeatedly. The first intercomparison has been carried out between the reference shunt for Asia and high current shunt of HPTD II in 2013. This paper compares the test results of the calibration in 2014 with them in 2015. The assigned new scale factor of high current sensors will be applied to high power tests in HPTD II until the next high current intercomparison.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.1
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• pp.150-155
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• 2009

Hysteresis current regulator has been used widely because of its simple principle and structure. However, when the current band width is too narrow or the applied voltage is relatively too high, the switching frequency increases abruptly and it makes large amount of heat. In this study, for single phase current control, the hysteresis current control is executed by adding 0 mode state and comparing the slope of the current reference, which decreases the switching frequency so much and make the current control much stable. These were proved with computer simulations.

• Current Optics and Photonics
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• v.3 no.6
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• pp.516-521
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• 2019

The electrical leakage levels of GaN-based light-emitting diodes (LEDs) containing leakage paths are estimated using photoluminescence (PL) and photovoltaic properties under photoexcitation conditions. The PL intensity and open-circuit voltage (V_OC) decrease because of carrier leakages depending on photoexcitation conditions when compared with reference values for typical LED chips without leakage paths. Changes of photovoltage-photocurrent characteristics and PL intensity due to carrier leakage are employed to assess the leakage current levels of LEDs with leakage paths. The current corresponding to the reduced V_OC of an LED with leakage from the photovoltaic curve of a reference LED without leakage is matched with the leakage current calculated using the PL intensity reduction ratio and short-circuit current of the LED with leakage. The current needed to increase the voltage for an LED with a leakage under photoexcitation from V_OC of the LED up to V_OC of a reference LED without a leakage is identical to the additional current needed for optical turn-on of the LED with a leakage. The leakage current level estimated using the PL and photovoltaic properties under photoexcitation is consistent with the leakage level measured from the voltage-current characteristic obtained under current injection conditions.