• Journal of Power Electronics
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• v.10 no.4
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• pp.419-427
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• 2010

A parallel control strategy in capacity proportion frequency allocation mode for shunt active power filters (APFs) is proposed to overcome some of the difficulties in high power applications. To improve the compensation accuracy and overall system stability, an improved selective harmonic current control based on multiple synchronous rotating reference coordinates is presented in a single APF unit, which approximately implements zero steady-state error compensation. The combined decoupling strategy is proposed and theoretically analyzed to simplify selective harmonic current control. Improved selective harmonic current control forms the basis for multi-APF parallel operation. Therefore, a parallel control strategy is proposed to realize a proper optimization so that the APFs with a larger capacity compensate more harmonic current and the ones with a smaller capacity compensate less harmonic current, which is very practical for accurate harmonic current compensation and stable grid operation in high power applications. This is verified by experimental results. The total harmonic distortion (THD) is reduced from 29% to 2.7% for a typical uncontrolled rectifier load with a resistor and an inductor in a laboratory platform.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.195-204
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• 2015

In this paper, the development of a cost-effective active power filter/uninterruptible power supply (APF/UPS) system with seamless mode transfer is described. The proposed scheme employs a pulse-width-modulation (PWM) voltage-source inverter and has two operational modes. First, when the source voltage is normal, the system operates as an APF, which compensates for the harmonics and power factor while boosting the DC-link voltage to be ready for the disturbance, without an additional DC charging circuit. A simple algorithm to detect the load current harmonics is also proposed. Second, when the source voltage is out of the normal range (owing to sag, swell, or outage), it operates a UPS, which controls the output voltage constantly by discharging the DC-link capacitor. Furthermore, a seamless transfer method for the single-phase inverter between the APF mode and the UPS mode is also proposed, in which an IGBT switch with diodes is used as a static bypass switch. Dissimilar to a conventional SCR switch, the IGBT switch can implement a seamless mode transfer. During the UPS operation, when the source voltage returns to the normal range, the system operates as an APF. The proposed system has good transient and steady-state response characteristics. The APF, charging circuit, and UPS systems are implemented in one inverter system. Finally, the validity of the proposed scheme is investigated with simulated and experimental results for a prototype APF/UPS system rated at 3 kVA.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.585-588
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• 2002

In this paper, the current controlled active poler filter(APF) with the performance of reducing harmonic and improving power factor is studied. It has high speed and good performance with low cost. The current controlled shunt APF is proposed, and the control part of APF is designed of SOC(System On Chip). So this system has low expense and good performance. In this study, the micro-controller which designed with VHDL. is applied to APF system. And the proposed technique in this paper demonstrates the excellent of the dedicated micro-controller. VHDL-based ASIC can simplify the process of development and has a competition in market because it reduces the consuming time for the design of IC(Integrated Circuit) in system level.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.6
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• pp.576-584
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• 2003

This paper presents a new control method of single-phase active power filter(APF) for the compensation of harmonic current components in nonlinear loads. Constructing a imaginary second-phase giving time delay to load currents, making single-phase system into the system that has two phases, complex calculation is possible. In the previous method, it made a imaginary-phase lagged to the load current T/4(here T is the fundamental cycle), but in proposed method, the new signal, which has the delayed phase through the filter, using the phase-delay property of low-pass filter, was used to the second phase. Instantaneous calculation of harmonic current is possible, because two phase have different phase. In this paper, it was done with instantaneous calculation using the rotating reference frames(RRF) that synchronizes with source-frequency, a reference of compensation currents, not applying to instantaneous reactive power theory which uses the existed fixed reference frames. The simulation and experiment about R-L loads using the current source were carried out, and the effect of the proposed method was preyed through the result of this experiment.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.431-433
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• 1995

Active Power Filters(APF) have been developed for several years to solve the harmonics disturbance problems on power system networks. This paper studies observer based digital algorithm and PWM technique for three phase current source APF by simulation. Both switching or outside white noises affect seriously at control signal for APF control system. Hence observer algorithm to reduce noises is used. A technique of generation gating patterns for the CSI topologies based on carrier PWM techniques is applied. The requirements imposed on gating signals are satisified by the appropriate combination of single phase switching patterns and short pulse generator.

• Journal of Power Electronics
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• v.11 no.6
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• pp.931-937
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• 2011

This paper presents a method for the performance improvement of a shunt active power filter (SAPF) using the indirect current control (ICC) scheme. Compared to the conventional direct current control (DCC) scheme, the ICC gives better performance with a lower number of sensors. A simplified and efficient control algorithm using a low cost Intel 80C196KC microcontroller is implemented using only two current sensors for the source current and one voltage sensor for the DC-link voltage of the SAPF circuit. The objective is to eliminate harmonics and to compensate the reactive power produced by non-linear loads such as an uncontrolled rectifier feeding an inductive load. The APF is realized using a three phase voltage source inverter (VSI) with a dc bus capacitor. Experimental results are presented to prove the better performance of the ICC method over the DCC one.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.534-535
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• 2014

This paper proposes parallel operation of multi function rapid-charger with an active power filter. Rapid-charger can be installed in public institutions or mart parking lot. But conventional charger has disadvantage that it can not be used as the active power filter in charging mode with only one charger. So using 3-parallel operation, effective mode transfer between battery charging and APF function can obtain effect of harmonic compensation and improving the utilization of the charger.

• Journal of Power Electronics
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• v.17 no.6
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• pp.1637-1649
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• 2017

This paper describes an intensive analysis of a harmonic identification algorithm in non-ideal voltages source systems. The dq-axis Fourier with a positive sequence voltage detector (DQFP) is a novel harmonic identification algorithm for active power filters. A compensating current control system based on repetitive control is presented. A design and stability analysis of the proposed current control are also given. The aim of the paper is to achieve a robustness of the harmonic identification in a distorted and unbalanced voltage source. The proposed ideas are supported by a hardware in the loop technique based on a $eZdsp^{TM}$ F28335 and the Simulink program. The obtained results are presented to demonstrate the performance of the harmonic identification and the control strategy for the active power filter in non-ideal systems.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.234-236
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• 2006

In this paper, APF(Active Power Filter) will be treated in order to improve the output current distortion of the AC source. APF generates the harmonic current which contributes to a source side harmonic reduction. We can extract the compensating current of the parallel APF with phase transformations and the proposed current control method. Therefore, the calculation times is short and the control method is simple compared with conventional hysteresis methods. Experimental results verify that the system using the proposed method appers a good performance.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.128-129
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• 2011

APF제어의 필요성은 고조파로 인한 손실을 줄이기 위함이다. 최근의 전력장치 사용의 증가로 인해 고조파 성분이 증가했고, 부하 또한 다이오드와 같은 디바이스의 사용으로 고조파가 증가 했다. 이러한 문제를 해결해야 고조파를 감소 시키고 효율을 높일 수 있다. 본 논문에서 제안하는 APF제어를 통하여 전원 역률 보상과 효율 향상의 타당성을 실험을 통해서 검증한다.