• 조명전기설비학회논문지
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• 제26권5호
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• pp.71-78
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• 2012

This paper presents a digital control solution to process capacitor current feedback of high performance single-phase UPS for non-linear loads. In all UPS the goal is to maintain the desired output voltage waveform and RMS value over all unknown load conditions and transient response. The proposed UPS uses instantaneous load voltage and filter capacitor current feedback, which is based on the double regulation loop such as the outer voltage control loop and inner current control loop. The proposed DSP-based digital-controlled PWM inverter system has fast dynamic response and low total harmonic distortion (THD) for nonlinear load. The control system was implemented on a 32bit Floating-point DSP controller TMS320C32 and tested on a 5[KVA] IGBT based inverter switching at 11[Khz]. The validity of the proposed scheme is investigated through simulation and experimental results.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.577-582
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• 1989

This is a study of the translational end-point control of a single link flexible arm-with a tip mass. The beam is mounted on a translational mechanism driven by the ball screw, whose rotation is controlled by DC servomotor. The problem of shifting the end-point from its initial position to the commanded position is studied analytically both for the open-loop control subjected to some path functions and for the closed-loop control using the feedback of the tip information.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(2)
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• pp.583-586
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• 2004

A typical method to control the single-phase power converter system is to utilize the zero-crossing PLL. However, this method is vulnerable to the voltage disturbance and affects the performance of controller This paper proposes a new single-phase PLL system that is composed of the adaptive linear combiner and the PI control. The operational principle was analyzed through theoretical approach and the performance was verified through simulations with MATLAB. The proposed PLL system shows rapidness and robustness in control under the voltage disturbances such as the sag, harmonics, and phase jump.

• 전기전자학회논문지
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• 제17권1호
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• pp.16-21
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• 2013

최근 주파수 합성기는 협대역으로 설계를 하거나 광대역 주파수 합성기의 경우 이중루프구조로 설계하여 위상잡음을 줄이는 방식을 사용하고 있다. 그러나 이중루프구조의 주파수 합성기는 전압제어발진기의 중심주파수 불일치와 추가적인 루프를 필요로 하는 단점을 가지고 있다. 본 논문에서는 800Mhz ~ 3Ghz를 지원하는 새로운 구조의 단일루프 형태의 다중제어 광대역 주파수 합성기를 제안한다. 본 논문의 주파수 합성기의 전압제어발진기는 Coarse 제어 전압과 Fine제어전압을 고정되며, 최종적으로 낮은 Kvco를 가지게 된다. 주파수 합성기의 모의실험은 UMC $0.11{\mu}m$ 공정에서 검증하였으며, 제안된 주파수 합성기는 다양한 응용분야에 사용될 수 있을 것으로 기대된다.

• 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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• 제5권2호
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• pp.104-108
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• 2005

This paper presents the performance improvement of voltage-mode controlled interleaved synchronous buck converters. This is a voltage-mode controlled scheme, where the controllers do not need an external saw-tooth generator for PWM generation and the loop design is easier. The controller implementation requires only a single error amplifier and gives almost current mode control performance. The control scheme uses voltage feedback with two loops similar to current mode control: one for the slow outer loop and the other for the faster inner PWM control loop. To improve the performance of the converter system a coupled inductor is used. This coupled inductor reduces the magnetic size and also improves the converter's transient performance without increasing the steady-state current ripple. The effectiveness of the proposed control scheme is demonstrated through PSIM simulations.

• Journal of Power Electronics
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• 제12권4호
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• pp.654-663
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• 2012

In this paper, a digital control strategy based on equivalent fundamental and odd harmonic resonators is proposed for single-phase DVRs. By using a delay block, which can be equivalent to a bank of resonators, it rejects the fundamental and odd harmonic disturbances effectively. The structure of the single closed-loop control system consists of a delay block, a proportional gain and a set of zero phase notch filters. The principle of the controller design is discussed in detail to ensure the stability of the system. Both the supply voltage and the load current feedforwards are used to improve the response speed and the ability to eliminate disturbances. The proposed controller is simple in terms of its structure and implementation. It has good performances in harmonic compensation and dynamic response. Experimental results from a 2kW DVR prototype confirm the validity of the design procedure and the effectiveness of the control strategy.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(5)
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• pp.233-236
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• 2001

In this paper, a robust controller for UPS inverter is designed using CDM (Coefficient Diagram Method) developed by S. Manabe, by which a low order controller guaranteeing the stability and robustness is easily designed. The proposed controller consists of two control loops, the inner current control loop and the outer voltage control loop. The robustness of the proposed controller is verified through the theoretic evolution and its simulation.

• 제어로봇시스템학회논문지
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• 제3권3호
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• pp.280-288
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• 1997

In this paper, we will show that the torque ripple in closed-loop drives of permanent magnet stepping motors is reduced as properly selected lead angle control method. We propose an instantaneous torque equation, which is the function of lead angle, to estimate the influence on torque ripple. We design a closed-loop lead angle control system based on the proposed instantaneous torque equation and measure the instantaneous torque in various excitation modes. It is shown that torque ripple is greatly reduced, as seen from the experimental results as well as from the computer simulation results. For example, torque ripple reduced from 78.25% to 46.82% in the case of 50 PPS single-phase excitation mode operation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국제학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.144-149
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• 1993

This paper discusses a design of a nonlinear control for a class of single-input double-output nonlinear mechanical systems. When conventional linearization methods are applied to the mechanical systems, some problems of oscillation and unstable phenomena arise. The proposed nonlinear control system resolves these problems. In this design the eigenvalues of the closed-loop nonlinear system are assigned to desired locations and local asymptotic stability of the closed-loop system. is guaranteed. The design method is applied to an inverted pendulum system with a moving weight mechanism. Experimental results show that the proposed nonlinear controller is more effective for stability than the usual linear controller.