• 대한전기학회논문지
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• 제39권3호
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• pp.254-262
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• 1990

In the active power filter, the PWM method for controlling the power converter plays an important role for the performance and the efficiency of the filter. In this paper, a new PWM method for the single phase current source type active power filter is presented, which is intended particularly for obtaining the maximum efficiency of the compensation. This method is basically based upon the optimized injection method, but in contrast to the existing method, this method adapts the optimized injection method by putting not only the pulse width, but also the pulse position into control variables. By doing this, when the number of pulses per one cycle is N, lower order harmonics up to the Nth order can be completely eliminated by the filter. So, this method is much more efficient than any other existing method. These characteristics are well verified by the computer simulations and the experiments.

• Journal of Power Electronics
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• 제12권5호
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• pp.830-841
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• 2012

Active power filters (APF) can be employed for harmonic compensation in power systems. In this paper, a fuzzy based method is proposed for identification of probable APF nodes of a radial distribution system. The modified adaptive particle swarm optimization (MAPSO) technique is used for final selection of the APFs size. A combination of Fuzzy-MAPSO method is implemented to determine the optimal allocation and size of APFs. New fuzzy membership functions are formulated where the harmonic current membership is an exponential function of the nodal injecting harmonic current. Harmonic voltage membership has been formulated as a function of the node harmonic voltage. The product operator shows better performance than the AND operator because all harmonics are considered in computing membership function. For evaluating the proposed method, it has been applied to the 5-bus and 18-bus test systems, respectively, which the results appear satisfactorily. The proposed membership functions are new at the APF placement problem so that weighting factors can be changed proportional to objective function.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 추계학술대회 논문집
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• pp.199-202
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• 2002

This paper suggests the control algorithm of a 3-phase 3-wire series active power filters which have harmonic voltage source and harmonic current source This suggested control algorithm can compensate harmonics which are generated by nonlinear load such as diode or thyristor converter and reactive power in 3-phase 3-wire power distribution system This control algorithm extracts a compensation voltage reference from performance function without phase transformation Therefore this control algorithm is simpler than any other conventional control algorithm. 3-phase 3-wire series active power filter and hybrid active power filter is manufactured and experiments are carried out for harmonic voltage source and harmonic current source to verify the effectiveness of presented control algorithm Experimental results are presented in this Paper, as well.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1343-1345
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• 2005

In this paper, control schemes are proposed for a propulsion system(Converter/Inverter) of the TTX(Tilting Train express). In developed traction converter, unity power factor control, compensation method of dc link voltage have been applied. Output current of converter contains harmonics ripple at twice input ac line frequency, which causes a ripple in the dc link voltage so that control scheme is developed in inverter system to reduce the pulsating torque current. At low speed region, vector control scheme is applied and slip frequency control is adopted at high speed region. The performance of propulsion system will be verified by simulation and prototype experimental results.

• 전력전자학회논문지
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• 제20권4호
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• pp.356-362
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• 2015

This paper presents a current control strategy in the synchronous reference frame for a single-phase PWM converter, which ensures sinusoidal input current control under the distorted source voltage and frequency condition. Given that the distorted source voltage distorts the phase angle for PWM converter control, the input current contains the same harmonics as the source voltage. Aside from the distorted voltage, the variation in source frequency reduces the performance of input current control. To achieve sinusoidal input current control under the distorted source voltage and frequency condition, this paper proposes a compensation strategy of current reference with the distortion component extracted from the phase angle and a detection strategy of frequency variation from the output of a synchronous reference frame phase-lock loop. The experimental results confirm the validity of the proposed method under the distorted source voltage and frequency condition.

• 전력전자학회논문지
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• 제9권6호
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• pp.544-552
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• 2004

본 논문은 Single Tuned Filter를 사용하여 11차와 13차 고조파를 동시에 제거하는 Hybrid 능동필터를 제안하였다. 제안된 Hybrid 능동필터는 Hybrid 능동필터의 Detuning 보상능력을 이용한 것으로, 하나의 필터를 이용하여 2개 이상의 고조파를 제거할 수 Topology를 보여주고 있다. 본 논문에서 다루는 Hybrid 능동필터는 Detuning 보상능력을 이용한 것이기 때문에 인버터 출력전압을 최적으로 설계하는 것이 필수적이다. 본 논문은 수동필터 부분의 커패시터 용량과 HVDC 시스템에서 발생되는 고조파 전류의 크기 그리고 수동필터의 공진주파수와 제어모드에 따라 인버터 출력전압이 변화함을 확인하였고, 이에 따른 최적의 인버터 전압을 구하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.85-87
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• 2008

The demand of a three phase PWM inverter for the purpose of power control or grid-connecting is increasing. This inverter is connected to a grid through an L-filter or LCL-filter to reduce the harmonics caused by switching. An LCL-filter can reduce the harmonic of a low switching frequency and generate a satisfactory level of grid side current with a relatively low-inductance than an L-filter. But the additional poles caused by the LC part affects a stability problem due to induced resonance of the system. This paper presents a compensation method using a power theory to improve performance, the designed LCL-filter system and to reduce the stability problems caused by resonance. The effectiveness of the proposed algorithm is verified by simulations.

• Journal of Power Electronics
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• 제12권5호
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• pp.800-812
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• 2012

This paper analyses the mathematical model and control strategies of a Hybrid Active Power Filter with Injection Circuit (IHAPF). The control strategy based on the load harmonic current detection is selected. A novel control method for a IHAPF, which is based on the analyzed control mathematical model, is proposed. It consists of two closed-control loops. The upper closed-control loop consists of a single fuzzy logic controller and the IHAPF model, while the lower closed-control loop is composed of an Adaptive Network based Fuzzy Inference System (ANFIS) controller, a Neural Generalized Predictive (NGP) regulator and the IHAPF model. The purpose of the lower closed-control loop is to improve the performance of the upper closed-control loop. When compared to other control methods, the simulation and experimental results show that the proposed control method has the advantages of a shorter response time, good online control and very effective harmonics reduction.

• Journal of Power Electronics
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• 제12권5호
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• pp.821-829
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• 2012

This research article presents a novel approach based on an instantaneous active and reactive power component (p-q) theory for generating reference currents for shunt active filter (SHAF). Three-phase reference current waveforms generated by proposed scheme are tracked by the three-phase voltage source converter in a hysteresis band control scheme. The performance of the SHAF using the p-q control strategy has been evaluated under various source conditions. The performance of the proposed control strategy has been evaluated in terms of harmonic mitigation and DC link voltage regulation. In order to maintain DC link voltage constant and to generate the compensating reference currents, we have developed Fuzzy logic controller with different (Trapezoidal, Triangular and Gaussian) fuzzy M.F.s. The proposed SHAF with different fuzzy M.F.s is able to eliminate the uncertainty in the system and SHAF gains outstanding compensation abilities. The detailed simulation results using MATLAB/SIMULINK software are presented to support the feasibility of proposed control strategy. To validate the proposed approach, the system is also implemented on a real time digital simulator and adequate results are reported for its verifications.

• 한국산업정보학회논문지
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• 제21권4호
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• pp.21-30
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• 2016

In a single-phase power factor correction (PFC), the standard cascaded control algorithm using a proportional-integral-derivative (PID) controller has two main drawbacks: an inability to track sinusoidal current reference and low harmonic compensation capability. These drawbacks cause poor power factor and high harmonics in grid current. To improve these drawbacks, this paper uses a proportional-integral-derivative-resonant (PIDR) controller which combines a type-III PID with proportional-resonant (PR) controllers in the PFC. Based on a small signal model of the PFC, the type-III PID controller was implemented taking into account the bandwidth and phase margin of the PFC system. To adopt the PR controllers, the spectrum of inductor current of the PFC was analyzed in frequency domain. The hybrid PIDR controller were simulated using PSCAD/EMTDC and implemented on a 3 kW PFC prototype hardware. The performance results of the hybrid PIDR controller were compared with those of an individual type-III PID controller. Both controllers were implemented successfully in the single-phase PFC. The total harmonic distortion of the proposed controller were much better than those of the individual type-III PID controller.