Faculty Profiles - DOKI, Shinji

Papers - DOKI, Shinji

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Position Sensorless Estimation for Surface Permanent Magnet Synchronous Motor Using Eddy Current Reviewed International journal

Kato S., Tomita M., Hasegawa M., Doki S.

23rd International Conference on Electrical Machines and Systems, ICEMS 2020 page： 1972 - 1976 2020.11

Authorship：Last author Language：English Publishing type：Research paper (international conference proceedings) Publisher：23rd International Conference on Electrical Machines and Systems, ICEMS 2020

The rotor position sensorless control of Surface Permanent Magnet Synchronous Motor (SPMSM) at a standstill and in the low-speed region is challenging because the motor has no magnetic saliency. Thus, the paper presents the development of a new rotor position-sensorless estimation method for SPMSM.In the proposed method, thin conductive non-magnetic materials are placed on the rotor surface. When the high-frequency voltage is applied, the eddy current flows through the materials, and the inductance is slightly changed depending on the rotor position. The position estimation from 0 to 360 angles (electrical degrees) where the field-oriented control (FOC) is required for SPMSM is realized using this inductance changes. The experiments show that the initial rotor position estimation error is less than 20 degrees ; thus, the proposed method is very useful.

DOI： 10.23919/ICEMS50442.2020.9291246

Scopus

Performance Evaluation of Position Sensorless Control by using Extended Electromotive Force including Overmodulation Region on Electric Vehicle Reviewed International journal

Kitamura K., Doki S.

23rd International Conference on Electrical Machines and Systems, ICEMS 2020 page： 550 - 554 2020.11

Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：23rd International Conference on Electrical Machines and Systems, ICEMS 2020

Position sensorless control of PMSMs is one of the important research object in terms of lowering cost, saving installation space and improvement of reliability. A previous research proposed a method to estimate EEMF(Extended Electromotive Force) excited by signal injection and speed for all speed range and confirmed its performance in EV. In this paper, position sensorless control including overmodulation is implemented to EV and evaluated its performance.

DOI： 10.23919/ICEMS50442.2020.9291125

Scopus

A Study on the Implementation of Vector Control System Using the Model Base Parallelization Tool on Multi-Core Processor Reviewed International journal

Kim J., Kato S., Honda S., Edahiro M., Doki S.

23rd International Conference on Electrical Machines and Systems, ICEMS 2020 page： 1951 - 1956 2020.11

The scope of embedded systems used by multi-core processors is widely applied to various products that require control, such as home appliances, industrial devices, transportation devices, and communication terminals. Model-Base Parallelization technology was proposed towards efficient parallelization to implement a control system in the introduction of multi-core processors. By applying MBP, it is possible to parallelization even details that people are not aware of, but the control system with numerous causal relationships still does not sufficiently utilize multi-core. Therefore, a method of inserting a time-delay is being studied as a method for improving the parallelization of multi-cores.In this paper, We describe the insertion location that improves parallelization and does not affect the control performance by inserting time-delay to implement the vector control system of PMSM on multi-core efficiently.

DOI： 10.23919/ICEMS50442.2020.9290965

Scopus

Design Method of Model Predictive Control for Development of Current Control System of PMSM Reviewed

Shimaoka M., Doki S.

IEEJ Transactions on Industry Applications Vol. 140 ( 11 ) page： 793 - 806 2020.11

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEEJ Transactions on Industry Applications

This paper describes the design method for Model Predictive Control (MPC) that is suitable for current control systems of Permanent Magnet Synchronous Motor (PMSM). A current control system based on MPC predicts future current behaviors for considerable input voltage and determines the optimum input voltage by evaluating these behaviors. Conventional MPC sets the cost function, making it effective for several control purposes. However, the suitability of the search space of conventional MPC has not been discussed and its achievable performance was limited. In this paper, we consider an appropriate search space for current control system of PMSM by referring to existing modulation methods and inverter operation. Then, we propose new MPC that satisfies that search space and show that the proposed MPC can usage from a linear region to a square-wave region by the appropriate search space.

DOI： 10.1541/ieejias.140.793

Scopus

PMSM電流制御系構築のためのモデル予測制御の設計法 Reviewed

嶋岡雅浩, 道木慎二

電気学会論文誌D Vol. 140 ( 11 ) page： 793-806 2020.11

PMSM電流制御系構築のためのモデル予測制御の設計法 Reviewed

嶋岡雅浩, 道木慎二

電気学会論文誌D Vol. 140 ( 11 ) page： 793-806 2020.11

Servo brake control based on finite control set-model predictive control with a voltage smoother Reviewed International coauthorship International journal

Kawai H., Cordier J., Kennel R., Doki S.

Proceedings - 2020 IEEE 2nd Global Power, Energy and Communication Conference, GPECOM 2020 page： 131 - 136 2020.10

Language：English Publishing type：Research paper (international conference proceedings) Publisher：Proceedings - 2020 IEEE 2nd Global Power, Energy and Communication Conference, GPECOM 2020

This study presents an angular position control strategy for servo brake motion of an electric motor based on a finite control set-model predictive control (FCS-MPC) with a voltage smoother. In the proposed control scheme, the controller predicts the future current, speed and angular position with a finite set of smoothed voltages and outputs the optimal smoothed voltage by using pulse width modulation (PWM). Smoothed voltages effectively reduce current ripple, which results in less parasitic oscillations of the angular position while tracking the reference target. The simulated and experimental results obtained with a permanent magnet synchronous motor (PMSM), fed by a 2-level 3-phase voltage source inverter, show that the proposed method has both excellent performance of current ripple reduction and excellent dynamic performance in servo brake motion.

DOI： 10.1109/GPECOM49333.2020.9247941

Scopus

Torque Ripple Reduction of IPMSM Considering Compensation of Nonlinearities of Magnetic Characteristics Reviewed

Akatsuka H.

IECON Proceedings (Industrial Electronics Conference) Vol. 2020-October page： 1102 - 1107 2020.10

信号重畳と速度により励起される拡張誘起電圧を利用した永久磁石同期モータの全速度域位置センサレス制御 Reviewed

二村拓未, 道木慎二

電気学会論文誌Ｄ Vol. 140 ( 8 ) page： 8589-596 2020.8

信号重畳と速度により励起される拡張誘起電圧を利用した永久磁石同期モータの全速度域位置センサレス制御 Reviewed

二村拓未, 道木慎二

電気学会論文誌Ｄ Vol. 140 ( 8 ) page： 8589-596 2020.8

モデル予測制御に基づくPMSM電流制御系の定常電流制御性能改善のための探索空間設計 Reviewed

嶋岡雅浩, 道木慎二

電気学会論文誌D Vol. 140 ( 6 ) page： 468-479 2020.6

モデル予測制御に基づくPMSM電流制御系の定常電流制御性能改善のための探索空間設計 Reviewed

嶋岡雅浩, 道木慎二

電気学会論文誌D Vol. 140 ( 6 ) page： 468-479 2020.6

Position sensorless control of PMSM at overall speed with extended-EMF excited by speed and signal injection Reviewed

Nimura T., Doki S.

IEEJ Transactions on Industry Applications Vol. 140 ( 8 ) page： 589 - 596 2020

Language：English Publishing type：Research paper (scientific journal) Publisher：IEEJ Transactions on Industry Applications

Extended electromotive force (EEMF) estimation method is a representative method used for position sensorless control of PMSM in the middle/high speed range. EEMF enables position estimation by utilizing back-EMF and the saliency of inductance. The amplitude of EEMF is adjusted to maintain it above a certain voltage by using a signal injection, regardless of the rotor speed. Thus, EEMF can be used as a single position estimator to estimate overall speed range. Based on the validation of a EEMF control performance and a parameter sensitivity analysis, this paper presents a position sensorless control system configured with a single position estimator from startup to middle/high speed. The necessary adjustment parameter and control performance of the actual machine are also presented.

DOI： 10.1541/ieejias.140.589

Scopus

Design of Search Space for Improving the Steady Current Control Performance of PMSM Current Control System based on Model Predictive Control Reviewed International journal

Shimaoka M., Doki S.

IEEJ Transactions on Industry Applications Vol. 140 ( 6 ) page： 468 - 479 2020

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：IEEJ Transactions on Industry Applications

This paper proposes a method to design the search space of Model Predictive Control (MPC) for improving the steady current control performance of Permanent Magnet Synchronous Motor (PMSM) current control system. A current control system based on MPC predicts the future current behaviors for considerable input voltage and determines the optimum input voltage by evaluating these behaviors. However, the basic MPC has inferior steady current control performance depending on the operating points. This is because the search space of basic MPC represented by voltage vectors is not suitable appropriate for PMSM current control. To overcome this problem, we consider difference of search space of basic MPC and current vector control with a modulator such as Pulse Width Modulation (PWM) or Space Vector Modulation (SVM) and clarify the necessary search space for improving the steady current control performance. Then we propose a design method for the search space, and through experimentation, we show that proposed design method can improve the steady current control performance.

DOI： 10.1541/ieejias.140.468

Scopus

Position Sensorless Control of Synchronous Reluctance Motors at Low-Speeds Reviewed International coauthorship International journal

Hatanaka T., Kato S., Tomita M., Hasegawa M., Doki S., Kato S.

2019 IEEE 4th International Future Energy Electronics Conference, IFEEC 2019 2019.11

Language：English Publishing type：Research paper (scientific journal) Publisher：2019 IEEE 4th International Future Energy Electronics Conference, IFEEC 2019

Synchronous reluctance motors (SynRMs) have attracted much attention because they do not require magnets. Position sensorless control of SynRMs at low speeds is necessary, and several methods have been proposed in this regard. A new position sensorless control method for SynRMs operating in the very low-speed region is proposed. This approach superimposes a high-frequency current with a small and constant amplitude and a constant frequency to the torque current for driving the SynRMs, by using a high-frequency current control system. It has been shown that robust position sensorless control against inductance variations can be realized using this proposed method. In the position sensorless control method based on a superimposing signal, the current should be small. Therefore, in this paper, the capability of the presented approach to achieve a minimum constant amplitude of the high-frequency current is investigated. The experimental results indicate that the proposed method is a feasible one as position sensorless control of SynRMs in very-low speed region even if the superimposed current has a minimum constant amplitude.

DOI： 10.1109/IFEEC47410.2019.9014679

Scopus

Pole Assignment of Full-Order Flux Observer to Realize Both MTPA Control and Position Sensorless Control of IPMSM Reviewed International journal

Kato S., Hatanaka T., Tomita M., Matsumoto A., Hasegawa M., Doki S.

2019 IEEE 4th International Future Energy Electronics Conference, IFEEC 2019 2019.11

Language：English Publishing type：Research paper (international conference proceedings) Publisher：2019 IEEE 4th International Future Energy Electronics Conference, IFEEC 2019

A flux model that can easily achieve both maximum torque per ampere (MTPA) control and position sensorless control of interior permanent magnet synchronous motors (IPMSMs), is proposed herein. Flux is proposed to be estimated using a full-order observer whose pole assignment is difficult because the order of the error equations of the observer becomes four, and the pole assignment of the full-order observer is proposed. This pole assignment of the full-order observer, in which robust flux estimation against velocity estimation error become possible, is obtained by solving a ?-positive real problem and a H8 control problem. Herein, the experimental result of the position sensorless control of IPMSMs indicates that the proposed pole assignment of the full-order observer is highly useful and can be used to realize MTPA control.

DOI： 10.1109/IFEEC47410.2019.9014918

Scopus

Comparison of two types of extended electromotive force models in middle / high speed ranges position sensorless control Reviewed International journal

Ohta K., Nimura T., Doki S.

2019 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe 2019.9

Authorship：Last author Language：English Publishing type：Research paper (international conference proceedings) Publisher：2019 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe

In this paper, two types of Extended Electromotive Force (EEMF) models are compared and the difference between the position sensorless control performance of these models are also discussed by mathematical equation and experiments.

DOI： 10.23919/EPE.2019.8915112

Scopus

Detection of contributing object to driving operations based on hidden Markov model Reviewed International journal

Kohjiro Hashimoto, Tetsuyasu Yamada, Takeshi Tsuchiya, Kae Doki, Yuki Funabora, Shinji Doki

International Journal of Advanced Robotic Systems Vol. 16 ( 5 ) page： 172988141987679 - 172988141987679 2019.9

Language：English Publishing type：Research paper (scientific journal) Publisher：SAGE Publications

With increase in the number of elderly people in the Japanese society, traffic accidents caused by elderly driver is considered problematic. The primary factor of the traffic accidents is a reduction in their driving cognitive performance. Therefore, a system that supports the cognitive performance of drivers can greatly contribute in preventing accidents. Recently, the development of devices for visually providing information, such as smart glasses or head up display, is in progress. These devices can provide more effective supporting information for cognitive performance. In this article, we focus on the selection problem of information to be presented for drivers to realize the cognitive support system. It has been reported that the presentation of excessive information to a driver reduces the judgment ability of the driver and makes the information less trustworthy. Thus, indiscriminate presentation of information in the vision of the driver is not an effective cognitive support. Therefore, a mechanism for determining the information to be presented to the driver based on the current driving situation is required. In this study, the object that contributes to execution of avoidance driving operation is regarded as the object that drivers must recognize and present for drivers. This object is called as contributing object. In this article, we propose a method that selects contributing objects among the appeared objects on the current driving scene. The proposed method expresses the relation between the time series change of an appeared object and avoidance operation of the driver by a mathematical model. This model can predict execution timing of avoidance driving operation and estimate contributing object based on the prediction result of driving operation. This model named as contributing model consisted of multi-hidden Markov models. Hidden Markov model is time series probabilistic model with high readability. This is because that model parameters express the probabilistic distribution and its statistics. Therefore, the characteristics of contributing model are that it enables the designer to understand the basis for the output decision. In this article, we evaluated detection accuracy of contributing object based on the proposed method, and readability of contributing model through several experiments. According to the results of these experiments, high detection accuracy of contributing object was confirmed. Moreover, it was confirmed that the basis of detected contributing object judgment can be understood from contributing model.

DOI： 10.1177/1729881419876794

Web of Science

Scopus

Other Link： http://journals.sagepub.com/doi/full-xml/10.1177/1729881419876794

Position sensorless control of IPMSM in overall speed range by extended EMF Reviewed International journal

Nimura T., Doki S.

2019 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe 2019.9

We present the redefined Extended EMF, which is proportional to not only rotor speed but also high frequency injected signal. We propose smooth and simple overall speed range position estimation by only using the redefined Extended EMF without switching control method at all.

DOI： 10.23919/EPE.2019.8915377

Scopus

Analysis and Evaluation of Current Control System of PMSM with Time-Delay to Improve Parallelization for Implementation on Multi-core Precessors Reviewed International journal

Kim J., Seiya K., Edahiro M., Doki S.

2019 22nd International Conference on Electrical Machines and Systems, ICEMS 2019 2019.8

Authorship：Last author Language：English Publishing type：Research paper (international conference proceedings) Publisher：2019 22nd International Conference on Electrical Machines and Systems, ICEMS 2019

With the introduction of multi-core processors, high performance of the control system has become possible. However, the use of multicore is not enough because parallelization is difficult in systems with sequential algorithms, such as motor current control systems. This paper describes the utilization of time-delay to improve parallelism in multi-core implementations of motor control systems. In addition, we propose a method of analyzing and evaluating the effect of time-delay on the control performance according to the insertion location.

DOI： 10.1109/ICEMS.2019.8921506

Scopus

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Papers - DOKI, Shinji