Faculty Profiles - DOKI, Shinji

Papers - DOKI, Shinji

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Position Sensorless Control for IPMSM of Spatial Inductance Distribution with Nonsinusoidal Inductance Waveform Based on Pattern Matching Method Reviewed International journal

Yuki Makaino, Shinji Doki

ELECTRICAL ENGINEERING IN JAPAN Vol. 201 ( 3 ) page： 35 - 42 2017.11

Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY

This paper presents a novel pattern matching based position sensorless control method for IPMSMs. A target IPMSM for the proposed method is designed such that it has high power and torque density, while also being significantly influenced by magnetic saturation. As previously reported in papers , for IPMSMs, heavy magnetic saturation affects the spatial distribution of phase inductances according to rotor positions. Most position sensorless controls at low speeds typically depend on the assumption that phase inductances have sinusoidal spatial distribution according to rotor positions. Therefore, it is difficult to apply conventional methods to IPMSMs with heavy magnetic saturation. In the proposed method, rotor position is estimated by pattern matching using feature values, so that the phase inductances have unique and reproducible value according to rotor positions. While template data sets are required for the proposed method, the assumption for sinusoidal phase inductances is not. In this paper, the effect of magnetic saturation for position estimation based on conventional methods is discussed in Section 1 and 2. Then, details of the proposed method are shown in Section 3. In Section 4, results of experiments carried out in steady state and transient state are presented. The effectiveness of the proposed method is verified through the experiments.

DOI： 10.1002/eej.23008

Web of Science

Scopus

A study of design method of full-order observer based on extended electromotive force for position sensorless control of IPMSMs Reviewed International journal

Toshiya Mabuchi, Ayame Makimura, Mutuwo Tomita, Shota Kondo, Masaru Hasegawa, Shinji Doki, Shinji Kato

2017 20th International Conference on Electrical Machines and Systems, ICEMS 2017 2017.10

Language：English Publishing type：Research paper (international conference proceedings) Publisher：Institute of Electrical and Electronics Engineers Inc.

Several position sensorless control methods of IPMSMs(Interior Permanent Magnet Synchronous Motors) using the observers have been proposed. In case of the full-order observers, these designs are difficult, because the order of the error equations of the observers becomes four. In this paper, for the position sensorless control of IPMSMs, a design method of the full-order observer based on the extended electromotive force (EEMF) is proposed. The experimental result shows that this design method of full-order observer is very useful.

DOI： 10.1109/ICEMS.2017.8056278

Scopus

A suppression method of the low frequency fluctuation of the neutral point potential under 3-level SHEPWM based on 3-order harmonic Reviewed International journal

Guan B., Doki S.

2017 20th International Conference on Electrical Machines and Systems, ICEMS 2017 2017.10

Language：English Publishing type：Research paper (international conference proceedings) Publisher：2017 20th International Conference on Electrical Machines and Systems, ICEMS 2017

Even though some methods have been put forward to solve the drift problem and the low frequency fluctuation problem of the neutral point potential (NPP) for three level neutral point clamped converters (TL-NPC), they are all just suitable for SPWM or SVPWM technologies. In some medium/high voltage high power applications, where SHEPWM is utilized to modulate the reference voltages, the drift problem and the low frequency fluctuation problem of the NPP become difficult. The duty cycle of phase voltage waveforms under SHEPWM can't be adjusted after the switching angles were calculated based on the optimal harmonic limits. For the severe low frequency fluctuation of the NPP, a suppression method is raised based on 3-order harmonic amendment in this paper. 3-order harmonic has no effect on the output performances under 3-phase 3-wire systems, but it can regulate the NPP. By analyzing the relationship between the NPP and 3-order harmonic, an optimal 3-order harmonic is determined. Using the optimal 3-order harmonic to calculate the switching angles for SHEPWM, the low frequency fluctuation of the NPP is suppressed obviously, which is important to improve the output performances and to reduce Dc-link capacitors. The simulation is done to verify the correctness and feasibility of proposed method.

DOI： 10.1109/ICEMS.2017.8056223

Scopus

Filter setting for improving torque control performance of IPMSMs in overmodulation region of inverter Reviewed International coauthorship International journal

Nakayama Y., Doki S.

2017 20th International Conference on Electrical Machines and Systems, ICEMS 2017 2017.10

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (international conference proceedings) Publisher：2017 20th International Conference on Electrical Machines and Systems, ICEMS 2017

This paper presents the filter setting for expand the operation range of IPMSMs in overmodulation region of inverter. To operate IPMSMs in the overmodulation region, it is necessary to deal with harmonics components. In this paper BSF is utilized to suppress the harmonic components, and its setting method is mentioned. The operation range in the overmodulation region is expanded appropriately by setting the filter focusing on resonant frequency of the system.

DOI： 10.1109/ICEMS.2017.8056395

Scopus

Position sensorless control of synchronous reluctance motors at very low speeds region using high-frequency current control system Reviewed International journal

Toshiya Mabuchi, Ayame Makimura, Mutuwo Tomita, Shota Kondo, Masaru Hasegawa, Shinji Doki, Shinji Kato

2017 20th International Conference on Electrical Machines and Systems, ICEMS 2017 2017.10

Language：English Publishing type：Research paper (international conference proceedings) Publisher：Institute of Electrical and Electronics Engineers Inc.

Synchronous reluctance motors (SynRMs) have attracted studies, because SynRMs have no magnets in the rotors. The position sensorless control at low speeds of SynRMs is now desired, and several methods have been proposed. In this paper, by using the high-frequency current control system, a new position sensorless control method of SynRMs at low speeds by superimposing high-frequency current whose amplitude is small constant value has been proposed. The experiments show that the proposed method is very useful even if the very low speeds region.

DOI： 10.1109/ICEMS.2017.8055979

Scopus

The compensation strategy on the drift voltage problem of dual modulation waves based neutral point potential control for three level converter Reviewed International journal

Guan B., Doki S.

IEEE International Symposium on Industrial Electronics page： 893 - 898 2017.8

Authorship：Lead author Language：English Publishing type：Research paper (international conference proceedings) Publisher：IEEE International Symposium on Industrial Electronics

Even if the dual modulation waves based neutral-point-potential (NPP) control for three-level converters is able to eliminate the low frequency NPP fluctuation, it just has the natural balancing characters for the NPP. Thus, a compensation strategy is necessary to solve the drift voltage problem of the NPP. The traditional compensators overcome the drift voltage problem by adjusting an offset voltage. Since there is no theoretical basis to determine the gain of the offset voltage, it may cause the over-adjustment. It is also difficult to master the law of the output waveform adjusted by the offset voltage. Given these defects of the traditional compensators, a new compensation factor (CF) is raised and the relationship of the CF, the NPP, the phase current and the Dc-link capacitors is analyzed in this paper. By adjusting the CF in a limit region analyzed in this paper, the drift voltage problem is well solved without over-adjustment. Since it is easy to know the law of the output waveform adjusted by the new CF, it can also decrease the switching frequency and avoid the three level modulation degrading to the two level modulation in some operation conditions. Simulation results verify the correctness and effectiveness of the proposed method.

DOI： 10.1109/ISIE.2017.8001364

Scopus

A study of position sensorelss control for IPMSM having non-sinusoidal inductance spatial distribution based on pattern matching method Reviewed International journal

Song H., Doki S.

2017 IEEE 3rd International Future Energy Electronics Conference and ECCE Asia, IFEEC - ECCE Asia 2017 page： 47 - 51 2017.7

Authorship：Last author Language：English Publishing type：Research paper (international conference proceedings) Publisher：2017 IEEE 3rd International Future Energy Electronics Conference and ECCE Asia, IFEEC - ECCE Asia 2017

A pattern matching method for position sensorless control of IPMSMs having non-sinusoidal inductance spatial distribution in standstill and very low speed region has been proposed. In the proposed method, the rotor position is estimated by comparing the phase current derivatives measured in a real-time with those in advanced. The current derivatives are obtained by measuring the phase currents twice at the certain voltage vector of inverter switching. The certain voltage vector not only must be created in all rotor position, but also must continue for at least a minimum time (tmin) to measure the currents twice. However there exists conditions which could not be secured tmin depending on the load current and the rotor position. In previous researches, switching-state phase shift method is utilized in order to create the certain voltage vector by injection high frequency voltage in all rotor position. In this paper, proposed various switching-state phase shift methods are explained and strong and weak points of each method are compared. Furthermore, the effectiveness and remaining issues of each methods are represented by experimental results.

DOI： 10.1109/IFEEC.2017.7992416

Scopus

The characteristic evaluation of the method to improve the voltage phase resolution of model predictive control for current control system of PMSM Reviewed International journal

Shimaoka M., Yokoyama S., Doki S.

2017 IEEE 3rd International Future Energy Electronics Conference and ECCE Asia, IFEEC - ECCE Asia 2017 page： 1641 - 1645 2017.7

This paper describes new model predictive control for high performance current control system of PMSM. The current control system based on FCS-MPC decides an inverter output voltage directly by searching. In a principle, this type controller can use not only PWM drive but also overmodulation and square wave drive[1]. However, conventional current control based on FCS-MPC is inferior to PWM modulated PI base control in the steady control performance for the reason of this method that the voltage phase resolution is coarse. The improvement of the voltage phase resolution of FCS-MPC can't realize by the restriction of the equipment. So, we have proposed new model predictive control to improve the voltage phase resolution not depending the limitation of the device[2], [3]. In this paper, we evaluate the characteristics of propose method comparing conventional current control based on FCS-MPC by the simulation and experimentation.

DOI： 10.1109/IFEEC.2017.7992293

Scopus

A new position sensorless control for IPMSM using feature values measured at zero voltage vector based on pattern matching method Reviewed International journal

Song H., Doki S.

Proceedings of the International Conference on Power Electronics and Drive Systems Vol. 2017-December page： 581 - 586 2017.7

Authorship：Last author Language：English Publishing type：Research paper (international conference proceedings) Publisher：Proceedings of the International Conference on Power Electronics and Drive Systems

This paper presents a position sensorless control method based on pattern matching method for high power density Interior Permanent Magnet Synchronous Motors (IPMSMs) that have non-sinusoidal inductance spatial distribution. In this paper, a new pattern matching method using feature values measured at zero voltage vector is proposed to improve the position estimation performance. By measuring the feature values at zero voltage vector, the number of feature value used in evaluation function is increased and it is advantageous for position sensorless control performance while keeping the wide operating range. Through experimental results, the effectiveness of the proposed method is presented.

DOI： 10.1109/PEDS.2017.8289201

Scopus

The steady current characteristics of the voltage phase resolution of model predictive modulated current vector control for PMSM Reviewed International journal

Shimaoka M., Doki S.

Proceedings of the International Conference on Power Electronics and Drive Systems Vol. 2017-December page： 166 - 171 2017.7

We have proposed new Model Predictive Control which can design the voltage phase resolution and average switching frequency independently for improving steady control performance. Our propose method is based on FCS-MPC, the controller decides switching timing of each phase during control period directly by predicting future current behaviors at each prediction period and evaluate each behaviors. Shortening prediction period can improve steady current control performance, however, calculation amounts of prediction become huge and interfere with implementation. So, our method needs understanding the characteristics of voltage phase resolution and the necessary voltage phase resolution in each operation point for realizing a same level steady current control performance of PI base current vector control using PWM. In this paper, we describe the steady current characteristic of the voltage phase resolution of our method.

DOI： 10.1109/PEDS.2017.8289233

Scopus

Impedance control system based on contact force distribution for wearable robot with tactile sensors Reviewed International journal

Sato A., Funabora Y., Doki S., Doki K.

SII 2017 - 2017 IEEE/SICE International Symposium on System Integration Vol. 2018-January page： 918 - 923 2017.7

Language：English Publishing type：Research paper (international conference proceedings) Publisher：SII 2017 - 2017 IEEE/SICE International Symposium on System Integration

The authors aim for safe assistance by feedback control of the contact force distribution in wearable robots. Since the wearable robot is in direct contact with the user, safety control is important. In order to improve safety, robot is desirable to be able to be controlled based on contact force: The force applied to the human body by the robot. A control system that feeds back joint torque as contact force has been proposed. However, since the joint torque is the resultant force of the contact force, there is a possibility that the dangerous contact force can not be detected directly. In this paper, the authors propose a new control system based on contact force distribution. The contact force distribution is sensed as pressure distribution by the tactile sensors attached to the robot surface. Impedance control in manipulator was expanded and applied to contact force distribution feedback control. The proposed method is compared with the control based on joint torque and the effectiveness of our method is verified.

DOI： 10.1109/SII.2017.8279340

Scopus

An Extraction Method of Causality Patterns between Situation and Human Action with Delay Time for Statistical Modeling of Human Action

Kohjiro Hashimoto, Kae Doki, Shinji Doki

ELECTRONICS AND COMMUNICATIONS IN JAPAN Vol. 100 ( 7 ) page： 3 - 17 2017.7

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

A modeling approach for human action is the focus of this paper. We design a human action model based on the stored data obtained during long-term monitoring of a person. This approach consists of the following two processes. First, several kinds of partial time series data that occur frequently are extracted from the stored data and taken to be human action patterns. Next, the extracted time series data are modeled based on a statistical modeling method such as the hidden Markov model. In this research, we focus on the extraction method for the time series data that occur frequently in the stored data. A person changes his actions according to changes in the situation around him. Moreover, it takes some time for him to perform his action after he recognizes the situation around himself. This time is called the delay time in this paper. A human action model that takes this delay time into consideration leads to greater accuracy in recognition and prediction of human actions based on that action. It is necessary to extract time series data for a situation and an action with the delay time as training data in order to generate the above human action model. In conventional methods, multidimensional time series data are used as the stored data without a distinction between the situation and action data. Also, some partial time series data that occur frequently are extracted from the stored data. Therefore, the delay time is not taken into account. In this paper, we propose a new extraction method for time series data that occur frequently with the time delay taken into consideration. In this method, sets of partial time series data that occur frequently with the delay time are extracted by evaluating the repeatability and similarity between the partial time series data sets with different occurrence frequencies. In the experiment, we extract the interaction motions that occur frequently between two subjects. The utility of the proposed method is examined based on the experimental results.

DOI： 10.1002/ecj.11961

Web of Science

Scopus

パーティクルフィルタを用いた自己位置推定のロバスト性向上を目指した確率分布の類似性に基づく動的なセンサ統合 Reviewed

巣山慶太, 舟洞佑紀, 道木慎二, 道木加絵

計測自動制御学会論文集 Vol. 53 ( 2 ) page： 169 - 177 2017.2

Position sensorless for IPMSM with heavy magnetic saturation based on pattern matching method Reviewed International journal

Song H., Doki S.

19th International Conference on Electrical Machines and Systems, ICEMS 2016 2017.1

Language：English Publishing type：Research paper (international conference proceedings) Publisher：19th International Conference on Electrical Machines and Systems, ICEMS 2016

A pattern matching method for position sensorless control of IPMSM with heavy magnetic saturation in standstill and very low speed region has been proposed. The rotor position is estimated by comparing the feature values measured in a real-time with in beforehand. To measure feature values, high frequency signal must be injected. The operation region of pattern matching method is limited by amplitude of injectable signal. This paper presents the operating region that could utilize pattern matching method. Also to expand the operating region, a new signal injection method and matching method are proposed. By using the proposed method, the same sampling time interval for measuring feature values could be obtained even smaller signal is injected.

Scopus

Position estimation system for PMSM position sensorless control in inverter overmodulation drive Reviewed International journal

Kosuke Kondo, Shinji Doki

IEEJ Journal of Industry Applications Vol. 6 ( 3 ) page： 165 - 172 2017

Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：Institute of Electrical Engineers of Japan

This study investigates compensation methods for harmonic components to realize PMSM position sensorless control in inverter overmodulation drive. While applying PMSMs as traction motor motors in an EV or HEV, operating PMSM in inverter overmodulation drive is an effective method to widen high-speed drive region of PMSM and achieve fast torque response when voltage saturates because it enable to utilize 27% higher fundamental voltage as compared to linear drive. In addition, position sensorless control is regarded as an important technique for adding a fail-safe function and downsizing of the drive system. However, the harmonic components which are inevitably generated in inverter overmodulation drive have negative effects on closed current control and position estimation systems. The key to realize position sensorless control in inverter overmodulation drive is an appropriate compensation for the harmonic components in the input voltage and input current of a the position estimator. There are several methods to achieve this, and differences in position estimation performance possibly exist among these methods. In this study, the compensation methods for harmonic components in overmodulation drive are compared, and a suitable compensation method for sensorless control is investigated through an experiment.

DOI： 10.1541/ieejjia.6.165

Web of Science

Scopus

A study on position sensorless control without any q-axis inductance by using Extended Electromotive Force with High frequency signal injection Reviewed

Kondo Shota, Doki Shinji, Tomita Mutuwo

2017 19TH EUROPEAN CONFERENCE ON POWER ELECTRONICS AND APPLICATIONS (EPE'17 ECCE EUROPE) page： . 2017

A New Position Sensorless Control for IPMSM Using Feature Values Measured at Zero Voltage Vector Based on Pattern Matching Method Reviewed

Song Hamin, Doki Shinji

2017 IEEE 12TH INTERNATIONAL CONFERENCE ON POWER ELECTRONICS AND DRIVE SYSTEMS (PEDS) page： 581-586 2017

Study on self-localization of an autonomous mobile robot using 2D maps generated with 3DLidar. Reviewed

DOKI Kae, SHINYA Ryu, FUNABORA Yuki, DOKI Shinji, TORII Akihiro, MOTOTANI Suguru

The Proceedings of JSME annual Conference on Robotics and Mechatronics (Robomec) Vol. 2017 page： 2P2 - D02 2017

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japan Society of Mechanical Engineers

<p>In this paper, we propose a self-localization method of an autonomous mobile robot using multiple 2D maps generated with information from 3D Lidar. In this method multiple 2D maps are generated with 3D point cloud divided into some groups based on the height from the ground. Then, multiple probability distributions for self-localization are generated with particle filter. The result of self-localization is calculated by selection and integration of the probability distributions based on KL divergence.</p>

DOI： 10.1299/jsmermd.2017.2P2-D02

Automatic Measuring Position Determination of UAVs for Visual Inspection System of Infrastructures Based on 3D Construction Model Considering Accuracy of Data Reviewed

ASA Kotaro, FUNABORA Yuki, DOKI Shinji, DOKI Kae

Transactions of the Society of Instrument and Control Engineers Vol. 53 ( 3 ) page： 229 - 235 2017

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Society of Instrument and Control Engineers

This paper presents a measuring-position-determination method of Unmanned Aerial Vehicles (UAVs) for automatic visual inspection system. In the proposed method, it is assumed that 3D model of the target infrastructure, the specification of measurement and UAV's features are given. Under those assumptions, the measuring positions are calculated considering the accuracy of data. In this paper, the usefulness of the proposed method is examined by a computer simulation assuming visual inspections for several bridges. In the simulation, measuring positions are determined assuming several types of UAVs for each bridge.

DOI： 10.9746/sicetr.53.229

CiNii Books

Robust Localization based on Integration of Position Information from Subsidiary UAVs Reviewed

MAEDA Keigo, FUNABORA Yuki, DOKI Shinji, DOKI Kae

The Proceedings of JSME annual Conference on Robotics and Mechatronics (Robomec) Vol. 2017 page： 2P2 - C02 2017

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japan Society of Mechanical Engineers

<p>In order to realize automatic inspection for infrastructure facilities using Unmanned Aerial Vehicles(UAVs), improvement robust localization of UAVs is needed. Especially, automatic flight could not be work in environments near facilities such as under the bridges. In this research, localization method is studied based on integration of position information gathering from subsidiary UAVs located in the surroundings of a main UAV. In this paper, as the first stage of this study, probabilistic position estimation model of subsidiary UAVs is modeled and integrated based on joint probability. By simulations with the models, influences of both position estimation errors of subsidiary UAVs and measurement errors of relative position are considered.</p>

DOI： 10.1299/jsmermd.2017.2P2-C02

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Papers - DOKI, Shinji