• Journal of Power Electronics
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• v.18 no.5
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• pp.1398-1408
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• 2018

In order to further improve the steady-state control performance of model predictive torque control (MPTC), a double-vector-based model predictive torque control without a weighting factor is proposed in this paper. The extended voltage vectors synthesized by two basic voltage vectors are used to increase the number of feasible voltage vectors. Therefore, the control precision of the torque and the stator flux along with the steady-state performance can be improved. To avoid testing all of the feasible voltage vectors, the solution of deadbeat torque control is calculated to predict the reference voltage vector. Thus, the candidate voltage vectors, which need to be evaluated by a cost function, can be reduced based on the sector position of the predicted reference voltage vector. Furthermore, a cost function, which only includes a reference voltage tracking error, is designed to eliminate the weighting factor. Moreover, two voltage vectors are applied during one control period, and their durations are calculated based on the principle of reference voltage tracking error minimization. Finally, the proposed method is tested by simulations and experiments.

• Transactions on Control, Automation and Systems Engineering
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• v.2 no.1
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• pp.7-12
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• 2000

A new speech enhancement algorithm for speech corrupted by slowly varying additive colored noise is suggested based on a state-space signal model. Due to the FIR structure and the unimportance of long-term past information, the receding horizon (RH) FIR filter known to be a best linear unbiased estimation (BLUE) filter is utilized in order to obtain noise-suppressed speech signal. As a special case of the colored noise problem, the suggested approach is generalized to perform the single blind signal separation of two speech signals. It is shown that the exact speech signal is obtained when an incoming speech signal is noise-free.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.12
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• pp.114-124
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• 2013

Recently, the real time simulator to develop the inverter drive board and motor control algorithm for high power induction motor and PM synchronous motor is required. In this paper, the real time simulator based on the voltage control for a PM synchronous motor is proposed. The resistor, inductor, and the induced voltage for the modeling of a PM synchronous motor is implemented by the power converter including the LCL filter and the PWM rectifier. The induced voltage of a PM synchronous motor is simulated by the capacitor voltage of the LCL filter, which is controlled by PI voltage controller and the deadbeat current controller. The operation and the simulated characteristics of the proposed real time simulator for a PM synchronous motor is verified by the simulation.

• Transactions on Control, Automation and Systems Engineering
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• v.2 no.2
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• pp.110-115
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• 2000

A receding horizon FIR filter is suggested for discrete time-varying systems, combining the Kalman filter with the receding horizon strategy. The suggested filter is shown to be an FIR structure that has many good ingerent properties. The suggested filter is represented in an iterative form and also in a standard FIR form. The suggested filter turns out to be a remarkable deadbeat observer that is often robust against system and measurement noises. It is also shown that the suggested filter is an unbiased estimator irrespective of any horizon initial condition. For the amenability to parallel and systolic implementation as well as the numerical stability, a square-root algorithm for the suggested filter is presented. To evaluate performance, the suggested filter is applied to a problem of unknown input estimation and compared with the existing Kalman filter based approach.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.10
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• pp.1487-1493
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• 2013

A new simple control method for active power filter, which can realize the complete compensation of harmonics is proposed. In the proposed scheme, a model-based digital current control strategy is presented. The proposed control system is designed and implemented in a form referred to as internal model control structure. This method provides a convenient way for parameterizing the controller in term of the nominal system model, including time-delays. As a result, the resulting controller parameters are directly set based on the power circuit parameters, which make tuning of the controllers straightforward task. In the proposed control algorithm, overshoots and oscillations due to the computation time delay is prevented by explicit incorporating of the delay in the controller transfer function. In addition, a new compensating current reference generator employing resonance model implemented by a DSP(Digital Signal Processor) is introduced. Resonance model has an infinite gain at resonant frequency, and it exhibits a band-pass filter. Consequently, the difference between the instantaneous load current and the output of this model is the current reference signal for the harmonic compensation.

• Journal of Power Electronics
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• v.18 no.5
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• pp.1369-1379
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• 2018

In this paper, a model predictive torque control (MPTC) without the use of a weighting factor for surface mounted permanent-magnet synchronous machine (SPMSM) drive systems is presented. Firstly, the desired voltage vector is predicted in real time according to the principles of deadbeat torque and flux control. Then the sector of this desired voltage vector is determined. The complete enumeration for testing all of the feasible voltage vectors is avoided by testing only the candidate vectors contained in the sector. This means that only two voltage vectors in the sector need to be tested for selecting the optimal voltage vector in each control period. Thus, the calculation time can be reduced when compared with the conventional enumeration method. On the other hand, a novel cost function that only includes the dq-axis voltage errors between the desired voltage and candidate voltage is designed to eliminate the weighting factor used in the conventional MPTC. Thus, the control complexity caused by the tuning of the weighting factor is effectively decreased when compared with the conventional MPTC. Simulation and experimental investigation have been carried out to verify the proposed method.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.2
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• pp.162-168
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• 2005

In this paper, a digital current mode control is designed for the power converter applications. The designed digital current mode controller is derived analytically from the continuous time small signal model of the power converters. Due to the small signal model based derivations of the control law, the designed control method can be applicable to boost, buck, and buck-boost converters. It is also proven that the controlled power converter employing the designed digital current mode controller is always stable regardless of an operating conditions. In order to show the usefulness of a designed controller, experiments are carried out using a 16bit DSP micro-processor, TMS320LF2406A.

• KIPS Transactions on Computer and Communication Systems
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• v.10 no.2
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• pp.53-58
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• 2021

In this paper, an alternative finite memory structure(FMS) smoothing filter is developed for discrete-time state-space model with a control input. To obtain the FMS smoothing filter, unbiasedness will be required beforehand in addition to a performance criteria of minimum variance. The FMS smoothing filter is obtained by directly solving an optimization problem with the unbiasedness constraint using only finite measurements and inputs on the most recent window. The proposed FMS smoothing filter is shown to have intrinsic good properties such as deadbeat and time-invariance. In addition, the proposed FMS smoothing filter is shown to be equivalent to existing FMS filters according to the delay length between the measurement and the availability of its estimate. Finally, to verify intrinsic robustness of the proposed FMS smoothing filter, computer simulations are performed for a temporary model uncertainty. Simulation results show that the proposed FMS smoothing filter can be better than the standard FMS filter and Kalman filter.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.5 no.4
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• pp.52-59
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• 1991

본 논문은 유한시간 정정응답 제어이론을 이용한 직류전동기의 속도제어에 대하여 논하였다. 유한시간 정정응답 제어계는 이산시간제어를 적용하므로 제어량 포화현상과 검출지연 문제가 발생하여 계통의 불안정을 초래한다. 이러한 문제를 해결하기 위하여 포화상태에서도 고속응답이 가능하도록 예측제어를 적용한 보상기를 제안한다. 실험 결과 지령치가 포화되지 않은 상태에서는 1샘플링시간으로 정정할 수 있었다. 지령치가 포화한 상태에서는 포화로부터 벗어난 후 1샘플링시간으로 정정할 수 있었다. 또한 예측제어를 적용하므로써 과도시의 오우버슈우트가 억제된 고속정정이 가능함을 알 수 있었다.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.752-755
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• 2004

본 논문에서는 전력변환회로의 소신호 모델을 이용한 데드빗 전류모드제어기를 설계하였다. 소신호 모델을 이용함으로써 부스투, 벅, 벅-부스트 컨버터에 모두 적용 가능한 데드빗 전류모드제어기를 설계 가능하고, 설계한 제어기는 모든 시비율 동작 조건에서 안정함을 확인하였다. 16bit 마이크로컨트롤러인 80C196KC를 사용하여 설계된 디지털 제어기를 구현하고, 아날로그제어기를 이용한 전류모드 제어에서의 동작 조건에 따른 불안정성 문제를 해결할 수 있음을 실험을 통해 확인하였다.