• 전력전자학회논문지
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• 제8권6호
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• pp.561-568
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• 2003

PWM 인버터의 출력전압을 제어하는 방식에는 2가지 제어기법이 있다. 첫 번째 방법은 전류제어기를 사용하여 출력전압을 제어하는 이중 제어루프를 갖는 제어방식이며, 두 번째 방법은 단일루프만으로서 출력전압을 제어하는 제어방식이다. 일반적으로 3상 PWM 인버터의 제어기는 각상 제어 PI제어기, 2상 정지좌표계 PI제어기, 동기 좌표계 PI제어기로 구성되며, 각상제어 PI제어기를 이용하여 3상의 독립된 출력측 전압 및 전류를 제어하도록 구성된다. 단일루프 전압제어기는 높은 출력 임피던스의 경우 이중제어루프 도다 더 낮은 성능을 나타내기만, 낮은 출력임피던스의 경우에는 또는 부하범위에서 좋은 제어성능을 나타낸다. 또한 시뮬레이션과 실험을 통하여 이를 검증하였다.

• 전력전자학회논문지
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• 제21권1호
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• pp.58-64
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• 2016

This study presents a design method for a single-loop voltage controller that is suitable for an arbitrary waveform generator (AWG). The voltage control algorithm of AWG should ensure high dynamic performance and should attain sufficient robustness to disturbances such as inverter nonlinearity, sensor noise, and load current. By analyzing the power circuit of AWG, control limitation and control target are presented to improve the dynamic performance of AWG. The proposed voltage control algorithm is composed of a single-loop output voltage control, an inverter current feedback term to improve transient response, and a load current feedforward term to prevent voltage distortion. The guideline for setting control gain is presented based on output filter parameters and digital time delay. The performance of the proposed algorithm is proven by experimental results through comparison with the conventional algorithm.

• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2354-2363
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• 2018

This paper proposed a novel double closed control strategy for single-phase voltage source pulse width modulation (PWM) rectifier based on active disturbance rejection control (ADRC) and dq current decoupling control. First, the mathematical model of the single-phase PWM rectifier in the d-q axis synchronous rotating reference frame is established by constructing a virtual component using a second-order generalized integrator (SOGI). Then, the mathematical model is simplified according to the active power conservation, and the first-order equation of single-phase PWM rectifier voltage outer loop is acquired. A linear auto-disturbance rejection controller is used to design the voltage outer loop according to the first-order equation. Finally, the proposed control strategy and the traditional PI control are compared and verified by simulation and physical experiments. Both simulation and experimental results confirm that the proposed control strategy has excellent dynamic performance and strong rejection ability to disturbances.

• Journal of Power Electronics
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• 제10권3호
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• pp.285-292
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• 2010

This paper presents a current mode integrated control technique (CM-ICT) using a modified voltage space vector modulation (MSVM) for Z-source inverter (ZSI) fed induction motor drives. MSVM provides a better DC voltage boost in the dc-link, a wide range of AC output voltage controllability and a better line harmonic profile. In a voltage mode ICT (VM-ICT), the outer voltage feedback loop alone is designed and it enforces the desired line voltage to the motor drive. An integrated control technique (ICT), with an inner current feedback loop is proposed in this paper for the purpose of line current limiting and soft operation of the drive. The current command generated by the PI controller and limiter in the outer voltage feedback loop, is compared with the actual line current, and the error is processed through the PI controller and a limiter. This limiter ensures that, the voltage control signal to the Z-source inverter is constrained to a safe level. The rise and fall of the control signal voltage are made to be gradual, so as to protect the induction motor drive and the Z-source inverter from transients. The single stage controller arrangement of the proposed CM-ICT offers easier compensation. Analysis, Matlab/Simulink simulations, and experimental results have been presented to validate the proposed technique.

• Journal of Power Electronics
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• 제9권1호
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• pp.124-131
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• 2009

This paper presents a PWM dc-ac converter regulation using a Single Input Fuzzy PI Controller (SIFPIC). The SIFPIC is derived from the signed distanced method, which is a simplification of a conventional fuzzy controller. The simplification results in a one-dimensional rule table, that allows its control surface to be approximated by a piecewise linear relationship. The controller multi-loop structure is comprised of an outer voltage and an inner current feedback loop. To verify the performance of the SIFPIC, a low power PWM dc-ac converter prototype is constructed and the proposed control algorithm is implemented. The experimental results show that the SIFPIC performance is comparable to a conventional Fuzzy PI controller, but with a much reduced computation time.

• 전기전자학회논문지
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• 제27권3호
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• pp.319-326
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• 2023

본 논문에서는 단상 전압 소스 인버터 (VSIs)의 강인한 출력 전압 제어를 위한 디지털 제어기 구현과 총 고조파 왜곡(T.H.D.v) 분석을 포함한 시뮬레이션 및 실험 결과를 제시한다. 일반적으로 VSI는 내부 루프의 전류 제어기에 비례 적분(PI) 제어기를 사용하고 외부 루프의 전압 제어기에 비례 공진 (PR) 제어기가 사용된다. 그러나, 비선형 부하에서 여전히 3차, 5차 및 7차와 같은 고차 고조파 왜곡이 발생한다. 따라서 본 논문에서는 고조파 왜곡을 억제하기 위해 홀수 고조파 주파수에 대한 공진 제어기를 포함한 비례 다중 공진 (PMR) 제어기를 제안한다. VSI 플랜트용 컨트롤러의 주파수 응답을 분석하고 PMR 컨트롤러를 설계합니다. 시뮬레이션을 통해 PI와 PMR을 전압 제어기로 사용할 때 출력 전압의 총 고조파 왜곡 특성을 비교 검증합니다. 선형 및 비선형 하중 조건이 모두 고려되었습니다. 마지막으로 PMR 제어기를 3kW급 VSIs 프로토 타입에 적용하여 그 유효성을 입증하였다.

• KIEE International Transactions on Power Engineering
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• 제3A권1호
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• pp.27-34
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• 2003

In this paper, the power conditioner composed of the stand-alone single-phase squirrel cage rotor type self-excited induction generator (SEIG) driven by prime movers such as a wind turbine and a micro gas turbine (MGT) is presented by using the steady-state circuit analysis based on the two nodal admittance approaches using the per-unit frequency in addition to a new state variable defined by the per-unit slip frequency along with its performance evaluations for the stand-alone energy utilizations. The stande-alone single-phase SEIG operating performances in unregulated voltage control loop are then evaluated on line under the conditions of the speed change transients of the prime mover and the stand-alone electrical passive load power variations with the simple theoretical analysis and the efficient computation processing procedures described in the part I of this paper. In addition, a feasuible PI controlled feedback closed-loop voltage regulation scheme of the stande-alone single-phase SEIG is designed on the basis of the static VAR compensate. (SVC) and discussed in experiment for the promising stand-alone power conditioner. The experimental operating performance results are illustrated and give good agreements with the simulation ones. The simulation and experimental results of the stand-alone single-phase SEIG with the simple SVC controller for its stabilized voltage regulation prove the practical effectiveness of the additional SVC control loop scheme including the PI controller with fast response characteristics and steady-sate performance improvements.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.202-205
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• 2006

In the PV power system, output of the PV array must contain inherent ripples due to the single-phase inverter. So the function of maximum power point tracking to increase the output efficiency of PV system is degraded. Therefore, to overcome this problem, this paper presents a control strategy for the reducing ripples of the PV array output in grid-connected photovoltaic power system. The proposed control system consists of two loops the maximum power point tracking loop using the perturbation and observation method is used to calculate the reference solar array terminal voltage(Vref) for reducing ripples of the PV array output and the PI control loop is used to regulate the solar array output voltage according to the Vref. The performance of proposing control strategy is analyzed by means of the PSCAD/EMTDC simulation. As a result, we may obtain the high performance of the proposed control strategy.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(2)
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• pp.799-802
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• 2004

There are many methods in controlling inverter's voltage and currents. most of all, PI control method is a general method. PI control has some merits. But, PI control has zero effect. So, steady-state response errors always exist by the zero effect. For removing the steady-state error, This paper presents the modeling, design and analysis of the double loop feedback control scheme. and computing the value of parameters and applying In the single-phase full bridge inverter for comparison and analysis between the PI control and PDFF control. The system model is employed to examine the dynamics of power circuit and select appropriate feedback variables for stable operation of the closed-loop UPS inverter system. It analyzes and proves the output characteristic of inverter system with the PDFF control.

• Journal of Power Electronics
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• 제3권3호
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• pp.185-196
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• 2003

In this paper, the single-phase static VAR compensator (SVC) is applied to regulate and stabilize the generated terminal voltage of the single-phase self-excited induction generator (single-phase SEIG) driven by a variable-speed prime mover (VSPM) under the conditions of the independent inductive load variations and the prime mover speed changes The conventional fixed gain PI controller-based feedback control scheme is employed to adjust the equivalent capacitance of the single-phase SVC composed of the fixed excitation capacitor FC in parallel with the thyristor switched capacitor TSC and the thyristor controlled reactor TCR The feedback closed-loop terminal voltage responses in the single-phase SEIG coupled by a VSPM with different inductive passive load disturbances using the single-phase SVC with the PI controller are considered and discussed herem. A VSPM coupled the single-phase SEIG prototype setup is established. Its experimental results are illustrated as compared with its simulation ones and give good agreements with the digital simulation results for the single-phase SEIG driven by a VSPM, which is based on the SVC voltage regulation feedback control scheme.