• 전자공학회논문지T
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• 제35T권3호
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• pp.96-102
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• 1998

본 논문에서는 스위칭시 ZVS 기능을 갖는 풀 브리지 위상전이 컨버터의 디지털 컨트롤러의 설계에 대해 연구하였다. 디지털 컨트롤러는 인버터나 전동기 구동 시스템에서 넓게 사용되었다. 그러나 디지털 컨트롤러는 고주파 스위칭 파워 서플라이 (특히 풀브리지 DC/DC 컨버터)에는 적용되지 못했었다. 따라서 본 논문에서는 ZVS 기능을 가진 풀 브리지 위상전이 컨버터의 디지털 컨트롤을 위한 방법을 제안하고, 기존의 아날로그 컨트롤러와 비교하였다. 수치 연산 패키지인 MATLAB을 이용한 컴퓨터 시뮬레이션을 통해 제어기 설계를 최적화하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제20권3호
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• pp.131-137
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• 1996

The existing digital governors are in the beginning stage. Placing the focus on the marine site, most of the digital governors developed are still using the simple PID algorithm. But, the performance of a diesel engine is widely changed according to the parameters of the PID controller. So, this article describes a new method to adjust the parameters of the PID controller in a marine digital governor. In this paper, the diesel engine is considered as a nonoscillatory second order system. A new method to adjust the parameters of the PID controller for speed control of a diesel engine is proposed by means of the model matching method. Also, the simulations by numerical methods are carried out in cases of the exact understanding or out of the parameters of a diesel engine respectively. And this paper confirms that the proposed new method here is superior to Ziegler & Nichols's method through the comparisons and analysis of the characteristics of indicial responses.

• 대한전기학회논문지
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• 제32권6호
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• pp.211-218
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• 1983

In this paper, an attempt is made to match the continuous state trajectory of the digital control system with that of its continuous data model. Matching the state trajectories instead of the output responses assures that the performances of the internal variables of the plant as well as the output variables are preserved in the discretization. The mathematical tool used in this research is an extended maximum principle of the Pontryagin type, which enables one to synthesize a staircase type of optimal control signals, such as the output signal of a zero-order hold asociated with a digital controller. A general mathematical expression of the digital controller which may be used to replace the analog controller of a general system while preserving as mauch as possible the performance characteristics of the original continuous-data control system is derived in this paper.

• 한국정보통신학회논문지
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• 제6권1호
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• pp.1-5
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• 2002

디지털 제어시스템을 설계하려면, 먼저 아날로그 시스템을 설계한 후, 이산화하여 디지털 시스템을 설계한다. 본 논문에서는 최적 디지털 제어기의 선계에 샘플치 제어이론을 적용한다. 특히, 아날로그 제어기들의 멀티레이트 이산화에 Η$_2$최적화를 이용한다. 멀티레이트 구조상 인과성 제약을 갖는 멀티레이트 Η$_2$최적화를 통해 해를 얻는다. 설계 예제를 통해, 기존 이산화 방법과 비교하여, 멀티레이트 설계방법의 우수성을 확인한다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제1권1호
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• pp.113-118
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• 2001

In this paper, we develop an optimal intelligent digital redesign method for a class of fuzzy-model-based controllers, effective for stabilization of continuous-time complex nonlinear systems. Takagi-Sugeno (TS) fuzzy model is used to extend the results of the classical digital redesign technique to complex nonlinear systems. Unlike the conventional intelligent digital redesign technique reported in the literature, the proposed method utilized the recently developed LMI optimization technique to obtain a digitally redesigned fuzzy-model-based controller. Precisely speaking, the intelligent digital redesign problem is converted to an equivalent optimization problem, and the LMI optimization method is used to find the digitally redesigned fuzzy-model-based controller. A numerical example is provided to evaluate the feasibility of the proposed approach.

• 한국정밀공학회지
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• 제4권4호
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• pp.25-35
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• 1987

This paper deals with the design of the digital controller for DC servo motor, and it is implemented for the cartesian coordinate 4 axes manipulator. A design method of the controller is adopted an algorithm using the digital position locked loop(DPLL) method and the linear PID control for the smooth motion. To simplify the hardware configuration of control system, 8279 keyboard/display controller, Z-80 CTC counter and 8255 PPI are used. Therefore the design method to control each motor as real-time is presented. To show effectiveness of the design, the PWM circuit and frequency/voltage converter are applied for the velocity control of robot system. When the proposed controller is applied to the 4-axes manipulator, it reveals that the error probabilities of X, Y and Z axis as 0.033%, 0.023% and 0.028% respectively.

• 제어로봇시스템학회논문지
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• 제12권7호
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• pp.644-649
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• 2006

In this paper, a methodology for estimating the model parameters of a discrete-time system and tuning a digital PID controller based on the estimated model and a genetic algorithm is presented. To deal with optimization problems regarding parameter estimation and controller tuning, pseudo-parallel genetic algorithms(PPGAs) are used. The parameters of a discrete-time system are estimated using both the model adjustment technique and a PPGA. The digital PID controller is described by the pulse transfer function and then its three gains are tuned based on both the model reference technique and another PPGA. A set of experimental works on two processes are carried out to illustrate the performance of the proposed method.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.298-303
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• 2004

The active magnetic bearing system for a TMP consists of four couples of magnets, five gap sensors with its amplifiers and a digital PID controller. For stabilizing and providing damping, digital PID controller is applied for each control axes and the inter-axis cross feedback controller is also applied to suppress low frequency vibration caused by gyroscopic moment of the rotor. Therefore in this paper, a digital controller of magnetic bearing for a TMP is design and examined.

• 전력전자학회논문지
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• 제5권2호
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• pp.163-169
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• 2000

전력변환시스템의 경제적인 설계를 위해서는 전력용 반도체소자의 전류정격을 모든 동작조건에서 최대한 이용하는 것이 매우 중요하다. 따라서 본 논문에서는 제안전압 한계의 변화, 연산지연시간, 시스템의 불확실성에 대해서도 오버슈트 없는 고속 전류제어 응답을 얻는 실용적인 디지털 전류제어기의 설계방법을 제안한다. 제안한 전류제어기는 수정된 시간지연보상기와 조건부 적분기를 갖는 고이득 PI제어기로 구성되어 있다. 제시된 시뮬레이션 및 실험 결과는 제안한 방법의 유효성을 보여준다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권12호
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• pp.609-614
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• 2001

This paper presents a multi output converter system that controls, simultaneously and independently, the separate Buck converter and Boost converter with the different specification by one DSP digital controller. As two separate converters are regulated by only one DSP, it is possible to achieve the simple digital control circuit for regulating multi output DC-DC converter. By setting the software switch state, PI and Fuzzy controller can be applied as a controller for each converter without any change of hardware. Also, it is included the control characteristics comparison between PI and Fuzzy controller. The control characteristics of each PWM DC-DC converter is validated by experimental results.