Simple Lead Angle Adjustment Method for Brushless DC Motors

Gu, Bon-Gwan,Choi, Jun-Hyuk,Jung, In-Soung The Korean Institute of Power Electronics 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.3

This paper presents a simple lead angle adjustment method for brushless DC motors. The proposed method is based on the motor current dynamics analysis during the current commutation interval. With the proposed scheme, the phase current and phase back-EMF voltage are in phase and the BLDC motor and drive system have a high efficiency induced by the reduced copper and conduction losses. Experimental results are shown to validate the proposed method.

Simple Lead Angle Adjustment for Brushless DC Motors

Bon-Gwan Gu,Jun-Hyuk Choi,In-Soung Jung 전력전자학회 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.3

This paper presents a simple lead angle adjustment method for brushless DC motors. The proposed method is based on the motor current dynamics analysis during the current commutation interval. With the proposed scheme, the phase current and phase back-EMF voltage are in phase and the BLDC motor and drive system have a high efficiency induced by the reduced copper and conduction losses. Experimental results are shown to validate the proposed method.

Start-Up Current Control Method for Three-Phase PWM Rectifiers with a Low Initial DC-Link Voltage

Gu, Bon-Gwan,Choi, Jun-Hyuk,Jung, In-Soung The Korean Institute of Power Electronics 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.4

When a PWM rectifier has a low DC-link voltage during startup, the output voltage vector cannot be high enough to regulate the input current. This lack of a PWM rectifier output voltage vector can cause an unregulated inrush current when the rectifier operation starts. This paper presents a PWM rectifier start-up current control algorithm for when it starts operation with a lower DC-link voltage than unloaded condition case. To avoid the unregulated inrush current caused by a lack of DC-link voltage, the proposed control scheme regulates the one phase current with one switch chopping and it generates the current command considering the uncontrolled current magnitude information, which is calculated in advance. Simulation and experiment results support the validity of the proposed method.

Development and Analysis of Interturn Short Fault Model of PMSMs With Series and Parallel Winding Connections

Bon-Gwan Gu,Jun-Hyuk Choi,In-Soung Jung IEEE 2014 IEEE transactions on power electronics Vol.29 No.4

<P>In this study, interturn short fault models of permanent magnet synchronous motors (PMSMs) employing series and parallel winding connections are developed using deformed flux models based on both fault winding flux information and inductance variations caused by cross flux linkages that depend on the distribution of same phase windings. As these models take into account fault winding within a three-phase winding dynamics analysis, they constitute fourth-order assessments. In the parallel-winding model, an additional dynamical analysis is used to describe variations in current distribution caused by the parallel connection between fault and healthy windings. Based on deformed flux modeling and positive sequence current assumptions, the proposed model is derived in both positive and negative sequence synchronous reference frames. A finite-element method-based simulation is applied to validate the proposed PMSM model.</P>

Start-Up Current Control Method for Three-Phase PWM Rectifiers with a Low Initial DC-Link Voltage

Bon-Gwan Gu,Jun-Hyuk Choi,In-Soung Jung 전력전자학회 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.4

When a PWM rectifier has a low DC-link voltage during startup, the output voltage vector cannot be high enough to regulate the input current. This lack of a PWM rectifier output voltage vector can cause an unregulated inrush current when the rectifier operation starts. This paper presents a PWM rectifier start-up current control algorithm for when it starts operation with a lower DC-link voltage than unloaded condition case. To avoid the unregulated inrush current caused by a lack of DC-link voltage, the proposed control scheme regulates the one phase current with one switch chopping and it generates the current command considering the uncontrolled current magnitude information, which is calculated in advance. Simulation and experiment results support the validity of the proposed method.

Online Load Torque Compensator for Single Rolling Piston Compressor

Bon-Gwan Gu,Jun-Hyuk Choi,In-Soung Jung 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

A single rolling piston compressor (SPRC) is commonly applied to the low power room air-conditioning system because of the low cost. The SRPC has only one compression and discharge process per each mechanical rotation. During compression process of the refrigerants, the load torque is quite high. On the other hand, during discharge process, of the refrigerant from the compressor room, the load torque is low. This load torque variation makes speed ripple and induce severe vibration, which causes fatigue failures of pipes and compressor parts at low speed. To relieve the vibration, the compressor usually operates in the high speed range where the rotor and piston inertia reduce the vibration phenomenon. Or a predefined feed-forward load torque compensator is used at low speed to minimize the speed ripple and vibration. However, since the load torque variation varies depending on the temperature, pressure, and speed, the predefined load torque table, based on one operating condition, is not appropriate to all. In this paper, an on-line load torque observer for SRPC is proposed. The proposed method utilizes the speed ripple as load torque ripple factor. The speed ripple is transformed into frequency domain and compensates each frequency harmonic term in a feed-forward way independently. Experimental results are presented to verify the proposed method.

Single rotary compressor의 저진동 저속제어를 위한 자동 부하 보상 알고리즘

구본관(Bon-Gwan Gu),최준혁(Jun-Hyuk Choi),정인성(In-Soung Jung) 전력전자학회 2010 전력전자학술대회 논문집 Vol.2010 No.11

저용량 에어컨의 압축기에 많이 사용되는 Single rotary 방식은 하나의 피스톤만을 채용하여 가격적인 면에서 큰 이점을 가진다. 그러나, 압축기 모터가 1회전할때 마다 압축과 토출을 단 1회 거치게 되므로, 부하변동을 심하여 진동이 많이 발생하는 단점이 있다. 이러한 단점을 보완하기 위하여 Single rotary를 사용하는 에어컨 제품에서는 저속에서의 운전을 회피하거나 하나의 운전점에 대한 전향보상기를 채용하여 진동을 저감시켜왔다. 본 논문에서는 모든 운전점에서 보상이 가능하도록 압축과 토출로 인한 부하의 패턴에서 각 주파수 성분을 분석하여 자동으로 부하 토크를 보상하는 알고리즘을 제안한다. 제안된 방법은 가장 영향이 큰 1차와 2차 주파수 성분의 속도 리플의양을 FFT 하고, 그 양이 작아지는 방향으로 부하 토크를 전향제어방식으로 인가하는 방식이다. 제안된 방식을 이용하여 저속 운전에서 진동이 저감 되는것을 실험을 통하여 보였다.

TMS320F240 DSP 컨트롤러를 이용한 서보모터 드라이브 개발

구본관(Bon-Gwan Gu),김준하(Junha Kim),남광희(Kwanghee Nam) 전력전자학회 1998 전력전자학술대회 논문집 Vol.- No.-

본 논문에서는 TI(Texas Instruments) 사의 DSP칩 TMS320F240을 이용한 벡터드라이브 설계를 한다. TMS320F240은 서보모터드라이브에 적합하게 상품화 된 칩으로 산업용 로봇제 어에 필요한 대부분의 주변회로를 포함하고 있다. 이를 이용해서 제어기를 구성하면 적은 비용으로 신뢰성 높은 제어기를 구성할 수 있다. 드라이브는 크게 제어회로부와 파워회로부로 나누어서 설계했으며, AC서보모터에 벡터제어로 실제적용을 했다.<br/> <br/>

3차원 얼굴 모델링과 예측시스템

구본관(Bon-Gwan Gu),정철희(Cheol-Hui Jeong),조선영(Sun-Young Cho),이명원(MyeongWon Lee) 한국컴퓨터그래픽스학회 2011 컴퓨터그래픽스학회논문지 Vol.17 No.1

본 논문에서는 3차원 3D 얼굴 스캔 데이터와 사진 이미지를 이용하여 3D얼굴 모델을 생성하고 향후의 얼굴을 예측하는 시스템 개발에 대해 기술한다. 본 시스템은 3차원 텍스처매핑, 얼굴 정의 파라미터 입력도구, 3차원 예측 알고리즘으로 구성되어 있다. 3차원 텍스처 매핑 기능에서는 3D 스캐너로 획득한 얼굴 모델과 사진 이미지를 이용하여 특정 연령에서의 새로운 얼굴 모델을 생성한다. 텍스처매핑은 3D 스케너로부터 획득한 메쉬 데이터에 정면과 좌우 측면의 세 방향의 사진 이미지를 이용하여 매핑하였다. 얼굴 정의 파라미터 입력도구는 3차원 텍스처매핑에 필요한 사용자 인터페이스 도구로서, 얼굴 모델의 정확한 재질값을 얼굴 사진으로부터 얻기 위하여 사진과 3D 얼굴 모델의 특징점을 일치시키는데 사용된다. 본 연구에서는 한 얼굴의 향후 연령대에서의 얼굴 모델을 구하기 위하여 100여개의 얼굴 스캔 데이터베이스를 이용한 통계적 분석에 의해 재질값을 예측 계산하여 해상도 높은 재질값을 가지는 모든 연령대의 3D 얼굴모델을 구성하였다. In this paper, we describe the development of a system for generating a 3-dimensional human face and predicting it"s appearance as it ages over subsequent years using 3D scanned facial data and photo images. It is composed of 3-dimensional texture mapping functions, a facial definition parameter input tool, and 3-dimensional facial prediction algorithms. With the texture mapping functions, we can generate a new model of a given face at a specified age using a scanned facial model and photo images. The texture mapping is done using three photo images - a front and two side images of a face. The facial definition parameter input tool is a user interface necessary for texture mapping and used for matching facial feature points between photo images and a 3D scanned facial model in order to obtain material values in high resolution. We have calculated material values for future facial models and predicted future facial models in high resolution with a statistical analysis using 100 scanned facial models.

IPM모터의 턴쇼트 고장모델에 관한 연구

구본관(Bon-Gwan Gu) 전력전자학회 2015 전력전자학회 논문지 Vol.20 No.4