Torque-Angle-Based Direct Torque Control for Interior Permanent-Magnet Synchronous Motor Drivers in Electric Vehicles

Xin Qiu,Wenxin Huang,Feifei Bu 전력전자학회 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.6

A modified direct torque control (DTC) method based on torque angle is proposed for interior permanent-magnet synchronous motor (IPMSM) drivers used in electric vehicles (EVs). Given the close relationship between torque and torque angle, proper voltage vectors are selected by the proposed DTC method to change the torque angle rapidly and regulate the torque quickly. The amplitude and angle of the voltage vectors are determined by the torque loop and stator flux-linkage loop, respectively, with the help of the position of the stator flux linkage. Furthermore, to satisfy the torque performance request of EVs, the nonlinear dead-time of the invertor caused by parasitic capacitances is considered and compensated to improve steady torque performance. The stable operation region of the IPMSM DTC driver for voltage and current limits is investigated for reliability. The experimental results prove that the proposed DTC has good torque performance with a brief control structure.

Torque-Angle-Based Direct Torque Control for Interior Permanent-Magnet Synchronous Motor Drivers in Electric Vehicles

Qiu, Xin,Huang, Wenxin,Bu, Feifei The Korean Institute of Power Electronics 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.6

A modified direct torque control (DTC) method based on torque angle is proposed for interior permanent-magnet synchronous motor (IPMSM) drivers used in electric vehicles (EVs). Given the close relationship between torque and torque angle, proper voltage vectors are selected by the proposed DTC method to change the torque angle rapidly and regulate the torque quickly. The amplitude and angle of the voltage vectors are determined by the torque loop and stator flux-linkage loop, respectively, with the help of the position of the stator flux linkage. Furthermore, to satisfy the torque performance request of EVs, the nonlinear dead-time of the invertor caused by parasitic capacitances is considered and compensated to improve steady torque performance. The stable operation region of the IPMSM DTC driver for voltage and current limits is investigated for reliability. The experimental results prove that the proposed DTC has good torque performance with a brief control structure.

교류전동기의 주기적인 토크리플 보상알고리즘

김병섭,최종우 전력전자학회 2006 전력전자학회 논문지 Vol.11 No.6

The electrical frequency synchronized periodic torque ripple exits in the AC motor. There are various sources of torque ripple in AC motor such as current measurement error, dead time, etc. This paper proposes a compensation algorithm which suppresses undesired side effect known as the periodic torque ripple of AC motor. The torque ripple compensation classified as the speed ripple detector and torque ripple compensator. This paper proves a speed ripple minimization at steady state by analysis of torque ripple compensator. A new speed ripple detector improves the performance of torque ripple compensation algorithm. The simulation and experimental results show that the compensation algorithm is effective and the torque ripple compensation method improves the performance of speed ripple detector by eliminating torque ripples effectively. 교류 전동기는 전류의 측정오차와 데드타임(dead time) 등의 영향으로 전기각주파수에 동기된 주기적인 토크리플이 발생한다. 본 논문에서는 주기적인 토크리플 보상알고리즘을 제안한다. 보상기는 토크리플에 의해 생성된 속도리플의 크기을 관측하는 속도리플 관측기와 관측한 양으로 토크리플을 보상하는 토크리플 보상기로 나누어진다. 본 논문에서는 토크리플 보상기의 해석을 통해 정상상태에서 속도리플이 제거되고 새롭게 제안된 속도리플 관측기을 적용하여 성능이 향상됨을 보였다. 제안한 주기적인 토크리플 보상알고리즘에 의해 토크리플 성분이 보상됨을 모의실험과 실험을 통해 검증하였다.

Torque Ripple Reduction Using Torque Compensation Effect of an Asymmetric Rotor Design in IPM Motor

Yong-Suk Hwang,Myung-Hwan Yoon,Jin-Cheol Park,Jung-Pyo Hong 한국자기학회 2017 Journal of Magnetics Vol.22 No.2

In this paper, torques of two motors are compared by Finite Element Analysis (FEA). One has a symmetric rotor structure and the other has an asymmetric rotor structure. The comparison shows that the asymmetric rotor structured motor has reduced torque ripple compared to the symmetric. The torque of the compared motor models was analyzed by separating into magnetic torque and reluctance torque. Through the analysis of torque component separated, it is shown that the magnetic torque and the reluctance torque compensate each other in the motor with the asymmetric structure rotor. Here “compensate” means decrementing the effect of one or more harmonics. It is shown how this compensation appears between the magnetic torque and the reluctance torque by looking into back electro motive force (emf) and the relative permeability distribution of rotor core.

ENGINE NET TORQUE COMPENSATION THROUGH DRIVELINE TORQUE ESTIMATION IN A PARALLEL HYBRID VEHICLE

Jinrak Park,Seibum Choi,Jiwon Oh,Jeongsoo Eo 한국자동차공학회 2019 International journal of automotive technology Vol.20 No.3

In recent years, interest in smart and green vehicles has increased. There are many cases where engine net torque related control is performed when building smart and green car systems. Speed tracking control in autonomous driving, or optimal transmission shift control is an example. The engine net torque is the sum of the engine indicated torque, accessory load torque, and frictional torque, and the starter motor torque in the case of a parallel hybrid vehicle. However, the estimation error of these torque items can cause the estimation error of the engine net torque. In this paper, a compensation method for the slowly varying uncertainty of the engine net torque in a parallel hybrid vehicle using a multiplicative constant is proposed. The adaptation of the multiplicative constant is conducted using the amount of change in the engine net torque estimated in the backward direction of the driveline. The proposed algorithm is verified based on production vehicle data.

A Safe Robot Arm with Safe Joints and Gravity Compensator

최동은,최준호,조창현,박신석,강성철 제어·로봇·시스템학회 2013 International Journal of Control, Automation, and Vol.11 No.2

This study presents a robot arm equipped with safe joints and multi DOFs gravity compensators. The safe joint, also referred to as “Spring-clutch”, is simple passive mechanism that consist of a spring, a cam, and a joint torque sensor. When the torque applied is lower than a pre-set threshold, the Spring-clutch serves as a rigid joint between the input and output. When the applied torque exceeds the threshold, the Spring-clutch is released and is free to rotate like a revolute joint, which significantly re-duces the collision force to avoid damage to the robot, as well as to humans. In addition, a compact joint torque sensor is installed in the Spring-clutch to measure the torque at the joint. Also, the analysis of energy and torque shows that the proposed mechanism can function as a gravity compensator capable of static balancing. Since joint torques vary in accordance with the pose of a manipulator (i.e., rotation angles), a Spring-clutch with a constant threshold torque cannot always guarantee the maximum collision torque in some poses of a manipulator. To overcome this limitation, a gravity compensator is adopted to eliminate the gravitational torque. In this research a bevel gravity compensator is applied which can perform static balancing completely. This paper describes the design principles and fabrication of the safety mechanisms and the robot arm.

DC-link 전압변동을 고려한 PMSM 토크제어의 성능 향상 방법

이정효(Jung-Hyo Lee),원충연(Chung-Yuen Won) 한국조명·전기설비학회 2014 조명·전기설비학회논문지 Vol.28 No.11

This paper proposes a PMSM torque control method considering DC-link voltage variation and friction torque. In general EV/HEV application, two dimensions look-up table(2D-LUT) is used for reference current generation due to its stable and robust torque control performance. Conventionally, this 2D-LUT is established by flux-torque table to overcome the DC-link voltage variation. However, the flux table establishment is more complex than the speed table establishment. Moreover, one flux data reflects several speed conditions in variable DC-link voltage, friction torque cannot be considered by using the flux table. In this paper, speed-torque 2D-LUT is used for current reference generation. With this table, PMSM torque control is well achieved regardless of DC-link voltage variation by the proposed control method. Simulation and experimental results validate improvement of torque control error through friction torque compensation.

외란관측기와 파라미터 보상기를 이용한 PMSM의 정밀속도제어

고종선,이택호,김칠환,이상설 전력전자학회 2001 전력전자학회 논문지 Vol.6 No.1

본 논문에서는 영구자석 동기 전동기의 정밀 속도 제어의 방법으로 외란 관측기를 이용한 외란 보상방법과 파라미터 추정에 의해 보상기의 이득을 조절하도록 함으로서, 외란이 없는 등가 지표시스템의 응답 특성을 추정하도록 제안하였다. 외란 관측기에 의한 보상방법은 잘 알려진 데드비트 외란 관측기를 이용하였으며 잡음에 약한 데드비트 관측기의 단점을 보완하기 위하여 후단필터로서 MA처리를 통하여 잡음에 대한 영향을 줄이도록 하였다. 또한 관측기의 단점을 보완하기 위하여 후단필터로서 MA처리를 통하여 잡음에 대한 영향을 줄이도록 하였다. 또한 관측기의 파라미터와 실제 시스템의 파라미터의 차이로 발생하는 외란 추정 오차를 줄이고자 실제 시스템과 파라미터 보상기로 구성된 등가 시스템이 지표 시스템이 되도록 구성하였다. 시스템에 사용된 RLS파라미터 추정기는 외란에 의하여 편향된 추정 특성을 가진다. 이러한 파라미터 추정문제에 대하여 파라미터 추정기가 높은 성능을 갖는 데드비트 외란 관측기를 포함하도록 함으로서 외란에 의한 문제를 해결하였다. 이와 같이 제안된 제어기는 외란 및 파라미터 변화를 갖는 시스템에서 강인한 고정밀 제어를 할 수 있으며, 이의 안정성과 효용성을 컴퓨터를 이용한 모의 실험과 TMS320C31이 내장된 DS1102 DSP 보드를 이용하여 실험으로써 보였다. This paper presents external load disturbance compensation that used to deadbeat load torque observer and regulation of the compensation gain by parameter estimator. As a result, the response of PMSM follows that of the nominal plant. The load torque compensation method is compose of a dead beat observer that is well-known method. However it has disadvantage such as a noise amplification effect. To reduce of the effect, the post-filter, which is implemented by MA process, is proposed. The parameter compensator with RLSM(recursive least square method) parameter estimator is suggested to increase the performance of the load torque observer and main controller. Although RLSM estimator is one of the most effective methods for online parameter identification, it is difficult to obtain unbiased result in this application. It is caused by disturbed dynamic model with external torque. The proposed RLSM estimator is combined with a high performance torque observer to resolve the problems. As a result, the proposed control system becomes a robust and precise system against the load torque and the parameter variation. A stability and usefulness, through the verified computer simulation and experiment, are shown in this paper.

엔드이펙터형 보행재활로봇의 토크 보상 메커니즘

한정우(Jeong-woo Han),김영환(Yeong Hwan Kim) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11

A torque compensation system has been studied in order to compensate the torque, in the direction of gravity, of the actuators of an end effector type gait rehabilitation robot. In the compensation system, a gas spring has been used, analyzed with the consideration of locations of installation and the following spring forces, and designed not to be exposed during the operation. The validity has been proved from the comparison of the analytic and experimental results before and after torque compensation. Based on the validity, the optimization of the system has been proposed with the consideration of patient’s allowed maximum weight.

중력 보상 기구 오차의 원인과 스프링 무게 중심 변화

서경준,서정욱 제어로봇시스템학회 2021 제어로봇시스템학회 국내학술대회 논문집 Vol.2021 No.6

Gravity compensation mechanism is one of the oldest topics in robotics. Mechanical gravity compensation can theoretically make the motor unloaded. Compensation torque generated by spring tension removes the torque caused by gravity. However, when tensile or compressive force is applied to the spring, the gravity center of the overall rotating linkage changes. It can even cause the overall compensation torque error. Specific research is needed that the center of gravity change causes errors in the overall torque. In the paper, assuming there is no friction and zero idler radius, the error torque due to the change of the gravity center of the overall rotating linkage is calculated. This research proposes a method to identify the overall cause of gravitational center change error caused by moving back and forth of the spring. Studying mechanisms for reducing gravity errors to improve performance will also help to design a multiple degree of freedom manipulator.