• Nuclear Engineering and Technology
• /
• v.53 no.3
• /
• pp.851-859
• /
• 2021

Small PWR can be used for power generation and heating. Considering that small PWR has the characteristics of flexible operating conditions and complex operating environment, the controller designed based on single power level is difficult to achieve the ideal control of small PWR in the whole range of core power range. To solve this problem, a flexible switching controller based on fuzzy controller and LQG/LTR controller is designed. Firstly, a core fuzzy multi-model suitable for full power range is established. Then, T-S fuzzy rules are designed to realize the flexible switching between fuzzy controller and LQG/LTR controller. Finally, based on the core power feedback principle, the core flexible switching control system of small PWR is established and simulated. The results show that the flexible switching controller can effectively control the core power of small PWR and the control effect has the advantages of both fuzzy controller and LQG/LTR controller.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.36 no.6
• /
• pp.574-580
• /
• 2008

This paper has proposed a controller switching scheme for full-envelope aircraft control using the bumpless transfer implementation algorithm developed recently. This switching scheme has combined by proper rules the common existing method which switches the controller according to attitude and mach number of the aircraft with an optimization method which uses the cost function relating to bump phenomenon by means of controller switching criterion. This paper exemplifies the control performance improvement via simulations applied to a high performance aircraft benchmark problem in a wide operating range to test the proposed controller switching scheme.

• Journal of Power Electronics
• /
• v.4 no.3
• /
• pp.152-160
• /
• 2004

This paper presents analysis, modeling, and design of a low-harmonic, isolated, active-clamped SEPIC for future avionics applications. Simpler converter dynamics, high switching frequency, zero voltage-Transition-PWM switching, and a single-layer transformer construction result. This paper describes complete design of a digital controller for a high-frequency switching power supply. Guidelines for the minimum required resolution of the analog-to-digital converter, the pulse-width modulator, and the fixed-point computational unit is derived. A design example based on a SEPIC converter operating at the high switching frequency is presented. The controller design is based on direct digital design approach and standard root-locus techniques.

• Proceedings of the KIPE Conference
• /
• 1998.07a
• /
• pp.85-89
• /
• 1998

A switching power stage is a very nonlinear system because it has two or more operation modes in one switching cycle. To model a switching power stage, the state space averaging method has been developed. Though it allows a unified treatment of a large variety of switching power stages, the model it yields is always very nonlinear. So, it is required to linearize the averaged model. But it is well known that a controller for a nonlinear plant designed by the linearization frequently fails in showing satisfactory control performance. Hence it is very natural to try to design a nonlinear controller for a switching power stage. In design of a switching power system, nonlinear control approaches such as adaptive control and fuzzy control have been widely studied so far. In this research, a recently developed control method, time delay control is briefly studied and a design example for a ZVS PWM half bridge converter is given. The performance of the time delay controller is compared to its conventional counterpart, PI controller by computer simulations.

• Journal of Institute of Control, Robotics and Systems
• /
• v.22 no.6
• /
• pp.417-423
• /
• 2016

Using a sliding mode controller and observer techniques, this paper presents a robust current controller for a DC motor in the presence of parametric uncertainties. One of the most important issues in the practical application of sliding mode schemes is the chattering phenomenon caused by switching actions. This paper presents a novel sliding mode controller that incorporates an integral control with a sliding mode disturbance observer to attenuate the chattering by reducing the controller/observer switching gains. The proposed sliding mode disturbance observer is designed to estimate a relatively slow varying signal in the equivalent lumped disturbance owing to system uncertainties. Combining the estimated uncertainty with the sliding mode control input, the proposed controller can achieve the control objective by using the relatively low gain of the controller. The proposed disturbance observer does not include the switching control input of the baseline sliding mode controller to reduce the observer switching gain. In the proposed approach, the integral sliding mode control is used to improve the steady state control performance. Comparative computer simulations are carried out to demonstrate the performance of the proposed method. Through the simulation results, the proposed controller realizes the robust performance with reduced current ripples.

• Proceedings of the KIEE Conference
• /
• 1989.11a
• /
• pp.401-404
• /
• 1989

In this paper an optimal LQ controller is designed for the output characteristic improvement of buck-type switching regulators. State-space averaging method is adopted for modelling of switching regulators. The LQ controller is derived via an unified operator form for the application to both continuous-time and discrete-time control systems. Some design parameters of the LQ controller are chosen through a computer simulation and the LQ controller is implemented by analog circuits.

• Journal of Institute of Control, Robotics and Systems
• /
• v.12 no.5
• /
• pp.425-430
• /
• 2006

To meet an increasing demand for high performance in gun dynamic plant, both a precise and a fast response positioning are strongly required for the gun servo system. A mode switching control(MSC) scheme, which includes a fine stabilizing controller, fast positioning one and a switching function, is widely used to meet this requirement. Stabilization is performed through PID controller, while a time optimal control method is used for target designation. In this paper, a modified PTOS(Proximate Time Optimal Servomechanism) algorithm is derived so as to accommodate the damping term in the gun plant model. Also, applying a mode switching strategy, the bumpless transfer is made possible when the controller switches from PTOS to PID. To show the effectiveness of the overall control system, simulation results are given including the gun dynamics.

• Journal of Institute of Control, Robotics and Systems
• /
• v.7 no.7
• /
• pp.582-588
• /
• 2001

The Multiple Model/Controller IMC(MMC-IMC) is a model-based control method which uses a set of model/controller pairs rather than a single model/controller to handle all possible operating conditions in the IMC control structure. During operation, one model/controller pair that best fit, for current plant situation is chosen by the switching algorithm. The major drawback of the switching controller is the bad transient performance due to the model error and the use fo linear controller for nonlinear plants. In this paper, we propose a method that transient response of the MMC-IMC using two recurrent neural networks. Simulation result shows that the proposed method represents better performance than the usual MMC-IMC`s.

• Proceedings of the KIEE Conference
• /
• 2001.11c
• /
• pp.15-17
• /
• 2001

This paper deals with a design problem of a switching-type fuzzy-model-based controller for a nonlinear system. Takagi-Sugeno(TS) fuzzy model and duffing forced-oscillation system are employed in designing the switching-type fuzzy controller. Finally, we analyze the stability of the global system controlled by the proposed controller.

• Journal of Institute of Control, Robotics and Systems
• /
• v.10 no.4
• /
• pp.317-324
• /
• 2004

The ink jet printer media advance system is required to be exactly driven to the target position via tracking the reference velocity profile to obtain the high quality print image. A single gain PID controller is not sufficient to fulfill the control objectives, the exact velocity tracking and the accurate positioning, at the same time. A dual PID controller and its switching strategy are presented in this paper to achieve the control objectives. The media advance system is controlled by two separate PID controllers, one of which is for velocity control, and the other is for position control. A PID controller controls the velocity of the media advance system until it reaches the predetermined switching position. When the media advance system passes the predetermined position, the controller is switched to the other PID controller which is more profitable for exact positioning. The switching position is determined by the estimated stop distance. The simulation and experimental results are presented to show the validity and effectiveness of the proposed controller.