• Journal of Power Electronics
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• 제18권6호
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• pp.1659-1669
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• 2018

An improved circulating current suppression control method is proposed in this paper. In the proposed controller, an outer loop of the average capacitor voltage control model is used to balance the sub-module capacitor voltage. Meanwhile, an individual voltage balance controller and an arm voltage balance controller are also used. The DC and harmonic components of the circulating current are separated using a low pass filter. Therefore, a multiple quasi-proportional-resonant (multi-quasi-PR) controller is introduced in the inner loop to eliminate the circulating harmonic current, which mainly contains second-order harmonic but also contains other high-order harmonics. In addition, the parameters of the multi-quasi-PR controller are designed in the discrete domain and an analysis of the stability characteristic is given in this paper. In addition, a simulation model of a three-phase MMC system is built in order to confirm the correctness and superiority of the proposed controller. Finally, experiment results are presented and compared. These results illustrate that the improved control method has good performance in suppressing circulating harmonic current and in balancing the capacitor voltage.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.1027-1028
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• 2006

In this paper, design of current and speed controller for DC motor drive system using Embedded Target for TI C2000DSP in Matlab/Simulink is introduced. Current and speed controller is designed and implemented using program simply and easily, and speed control response of DC motor can be advanced. Current and speed control of DC motor is carried in eZdsp F2812 control board using Embeded Target for TI C2000DSP in Matlab/Simulink. Speed feedback is processed through A/D converter using tacho generator as speed sensor, and current feedback is processed through A/D converter using hall sensor as current sensor. Controller is designed to PI current controller and PI speed controller. Current and speed response is verified through simulations and experiments.

• 전력전자학회논문지
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• 제11권5호
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• pp.426-430
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• 2006

본 논문에서는 제어 시지연을 갖는 고성능 PI 전류제어기에 대한 새로운 예측전류 적용방법을 모색한다. 먼저 선형 영구자석 동기전동기를 사용한 선형 서보 제어시스템에 존재하는 불가피한 전류예측 오차원인을 분석하고, 전류예측 오차와 제어 시지연을 고려한 전류제어 성능 개선 방법으로 수정된 동기좌표계 비간섭 PI 전류제어기를 제안한다. 그리고 시뮬레이션 및 실험 결과를 통하여 제안된 전류제어기가 서보 제어시스템에 존재하는 전류예측 오차와 제어 시지연이 있는 경우에도 개선된 전류제어응답을 보임을 검증하였다.

• 전력전자학회논문지
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• 제17권3호
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• pp.274-280
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• 2012

In this paper, three current controllers for a grid-connected PCS using an LCL filter are compared and analyzed. Current controllers discussed in this paper are linear controllers such as PI (proportional-integral), PR (proportional-resonant), and DB (deadbeat) controller. Both transient and steady state responses of each controller are compared through both simulation and experiment. Although the DB controller has the fastest transient response and the lowest THD in the steady state, the DB controller has two cycles delay of current response in the steady state and has the stability problem which can be occurred due to variation of the system parameters. On the one hand the responses of PR controller are not much different from that of DB controller but the other hand that are not only strong to noise of grid current but also have smaller THD than PI controller. Considering the response time and stability issue of three controllers, the PR controller has the best performance among three controllers and thus can be strongly recommended as a current controller for a grid-connected PCS.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.78-90
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• 2017

This paper presents the design of closed loop controllers operating a single-phase AC-DC three-level converter for improving power quality at AC mains. Closed loop inhibits outer voltage controller and inner current controller. Simulations of three level converter with three different voltage and current controller combinations such as PI-Hysteresis, Fuzzy-Hysteresis and Fuzzy tuned PI-Hysteresis are carried out in MATLAB/Simulink. Performance parameters such as input power factor and source current total harmonic distortion (THD) are considered for comparison of the three controller combinations. The fuzzy-tuned PI voltage controller with hysteresis current controller combination provides a better result, with a source-current THD of 0.93% and unity power factor without any source side filter for the three level converter. For load variations of 25% to 100%, a THD of less than 5% is obtained with a maximum value of only 1.67%. Finally, the fuzzy-tuned PI voltage with hysteresis controller combination is implemented in a Xilinx Spartan-6 XC6SLX25 FPGA board for experimental validation of power quality enhancement. A prototype 100 W, 0-24-48 V as output converter is considered for the testing of controller performance. A source-current THD of 1.351% is obtained in the experimental study with a power factor near unity. For load variations of 25% to 100%, the THD is found to be less than 5%, with a maximum value of only 2.698% in the experimental setup which matches with the simulation results.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
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• pp.384-386
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• 2006

In this paper, arc current controller is designed for the interruption of arc fault current which is occurred in the low voltage network. Arc in electrical network have the characteristics of low current, high impedance and high frequency. Conventional controller does not have the arc current interrupt function. Hence, arc current controller is designed for the interruption of arc fault current.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.982-983
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• 2006

This paper deals with an analysis and design of the state feedback current controller's gain in the three-phase current control systems. First, this paper derives the transfer function of the closed loop current control system and also compares the state feedback current controller with the conventional proportional integral controller. A new pole placement method by using the pole/zero cancellation method is proposed to give a simple and concrete concept with respect to the pole selection. Experimental results on the permanent magnet synchronous motor show that the proposed method is very useful to design the gain of the state feedback current controller.

• 전력전자학회논문지
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• 제1권1호
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• pp.7-11
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• 1996

From the cost-effective point of view, it is very important to design a current with the highest utilization factor of current capacity of power devices. This can be accomplished by a current controller without overshoot irrespective of the varying bounds of control voltage in PWM converters and the dead time due to the time delay. This paper suggests a novel decoupled controller with Smith-Predictor which has the fast control response without overshoot and steady stats error and also deal with the design method of the controller for PWM converters. The extensive digital simulations done by SIMULINK/MATLAB show that the suggested controller guarantees the full utilization of current capacity of power devices and the decoupled current control behavior.

• 한국산학기술학회논문지
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• 제17권3호
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• pp.473-479
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• 2016

본 논문은 가격이 저렴하고 친환경적이면서도 고성능, 고내구성, 구조적 단순함의 장점을 갖고 있어 최근에 폭넓은 관심을 받고 있는 스위치드 릴럭턴스 모터(SRM: Switched Reluctance Motor)의 보다 정확하고 안정적인 전류제어 방법에 대해 설명한다. 대부분의 전동기의 전류제어 방법에는 알고리즘과 제어 이득의 선정이 다른 제어기에 비해 상대적으로 간편한 PI 제어기를 이용한 방법이 주로 사용되어 왔다. 그러나 일반적인 PI 제어기는 SRM과 같이 고정자 권선의 전류 및 회전자의 위치마다 비선형적으로 파라미터가 급변하는 시스템의 경우 변하는 동작 지점마다 제어 이득을 조정해 주어야 하는 어려움이 발생한다. 본 논문에서는 비선형적으로 특성이 변하는 SRM 드라이브 시스템에 제어 성능이 우수한 자기동조 퍼지 제어기를 이용한 제어기법을 적용하여 비선형적인 파라미터의 변화에도 보다 안정적인 전류제어가 가능한 것을 보였다. 또한 Matlab/Simulink 시뮬레이션을 이용하여, SRM 드라이브의 전류제어에 PI 전류 제어기(PICC: PI Current Controller)와 자기동조 퍼지 전류 제어기(STFCC: Self-tuning Fuzzy Current Controller)를 각각 적용한 후 그 결과를 비교하였으며 제안한 자기동조 퍼지 제어기의 제어성능이 우수함을 확인하였다.

• 전기학회논문지
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• 제60권3호
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• pp.632-638
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• 2011

In this paper, a nonlinear controller is proposed to track the desired velocity and to cancel sinusoidal disturbances. The proposed method consists of a velocity tracking controller and internal model principles (IMPs). For the design of the velocity tracking controller, mechanical and electrical dynamic controllers are independently designed. For the mechanical dynamics, the velocity tracking controller generates the desired quadrature current to track the desired velocity. The current tracking controller is designed to guarantee the desired quadrature current and to regulate the direct current. Therefore, the proposed velocity tracking controller has a field-oriented control. Since the controllers of the mechanical and electrical dynamics are independently designed, the stability of the closed-loop system is demonstrated using passivity. Since both the cogging torque and DC current errors act as sinusoidal disturbances in PMSM, we use four add-on type IMPs that preserve the merits and performance of the pre-designed controller without sacrificing the closed-loop stability. The performance of the proposed method is validated via simulations.