• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.2
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• pp.124-129
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• 2005

This paper presents an advanced method for an initial pole position estimation of a Permanent Magnet Linear Synchronous Motor(PMLSM) that has an accurate incremental encoder for servo applications but does not have Hall sensors as a magnetic pole sensor. By appropriately using the secant method as a numerical method the proposed algorithm finds either of two zero force positions and then the correct d-axis by applying a q-axis test current. It only requires the tuned current controller and the relative position information md so it can be simply applicable to a rotary PMSM. The experimental results show the validity of the proposed method, which has an excellent performance with respect to an accurate pole position estimation under the minimal moving distance(average of about 85㎛) during the estimation process.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.1
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• pp.11-17
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• 2002

This paper describes on a position detection method for the motors which have repetitive operations using the Algorithmic State Machine(ASM), one of the digital logic design methods. With analyses for the incremental encoder output patterns, state diagram and state table are constructed and a digital circuit which can detect the changing point of direction of motor rotation is designed. To verify the validity of the designed circuit, simulations for all cases in which the direction of motor rotation is changed, are performed. Simulation results show the designed digital circuit can detect the direction of motor rotation accurately for all cases.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.6
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• pp.481-488
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• 2022

This study proposes compensation methods for the initial position error and torque ripple in vector control of two-phase hybrid stepping motors. Stepping motors have an asymmetrical structure due to misalignment, such as the eccentricity generated by the manufacturing and assembly process. When vector control is applied using the position information measured by an incremental encoder attached to the rotor shaft of such stepping motors, the following problems occur. First, an initial position error occurs during the forced excitation process for the initial rotor position alignment. Second, torque ripple corresponding to the mechanical rotation frequency is generated. In this study, these non-ideal phenomena that occur in vector control of the stepping motor are analyzed, and compensation methods are proposed to eliminate them. The validity of the proposed initial position error and torque ripple compensation methods is verified through experiments on a two-phase hybrid stepping motor drive system.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.2
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• pp.148-154
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• 2005

As the exciting point of each phase is determined by the position of rotor, the rotor's accurate position-information is needed for the Switched Reluctance Motor(SRM). When using an absolute-encoder or a resolver, to detect the location of rotor the initial starting is possible, as early sensing of rotor's location is possible. However, this is not appropriate, considering the economical efficiency, and in case of using the incremental-encoder, there's a problem at initial starting as it is not easy to track down the location of rotor at the very beginning. When using Hall-ICs, there's a fault, as it needs a special ring magnet. Considering the initial starting and economical efficiency, the optical sensor technique using a slotted-disk and an opto-interrupter is appropriate, however, this method needs three opto-interrupters and a slotted-disk when using the 6/4 pole SRM. Nevertheless, in this paper, it used only two optical sensors to operate 6/4 pole SRM and made the start up and also forward and reverse operation possible. By excluding the slotted-disc md shortening a optical sensor, it improved the convenience and economical efficiency of the production. Also, as the space for slotted-disc is no more needed, it was able to reduce the size of motor.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.11
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• pp.1038-1043
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• 2015

When the study on the relationship between the Head-of-Bed (HOB) angle and ventilator-associated pneumonia is performed, the fact that the HOB angle can only be measured intermittently imposes a significant limitation on the study. Therefore, there has been demand for the development of a device that can measure the HOB angle continuously. In this paper, we propose the rapid prototyping of an HOB measurement system using open-source hardware and software. The proposed system helps to maintain the HOB angle at a particular angle by displaying the angle and helps the medical study of pneumonia patients by enabling continuous data acquisition. Firstly, we eliminate the process of making an MCU board by utilizing an open-source hardware mbed LPC1768. Secondly, we reduce the software development time by using libraries and hence enabling the easy use of peripherals. Thirdly, for rapid prototyping, we build the enclosure of the proposed system using a 3D printer. The proposed system can be attached and detached to and from a bed. Therefore, we can attach it to the bed of a patient for whom measurement of the HOB angle is necessary. Finally, we check the measurement performance and the validity of the proposed system through an experiment utilizing an incremental encoder.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.11
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• pp.1423-1433
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• 2018

Recently, a permanent magnet synchronous motor of middle and small-capacity has high torque, high precision control and acceleration / deceleration characteristics. But existing control has several problems that include unpredictable disturbances and parameter changes in the high accuracy and rigidity control industry or nonlinear dynamic characteristics not considered in the driving part. In addition, in the drive method for the control of low-vibration and high-precision, the process of connecting the permanent magnet synchronous motor and the load may cause the response characteristic of the system to become very unstable, to cause vibration, and to overload the system. In order to solve these problems, various studies such as adaptive control, optimal control, robust control and artificial neural network have been actively conducted. In this paper, an incremental encoder of the permanent magnet synchronous motor is used to detect the position of the rotor. And the position of the detected rotor is used for low vibration and high precision position control. As the controller, we propose augmented state feedback control with a speed observer and first order deadbeat disturbance observer. The augmented state feedback controller performs control that the position of the rotor reaches the reference position quickly and precisely. The addition of the speed observer to this augmented state feedback controller compensates for the drop in speed response characteristics by using the previously calculated speed value for the control. The first order deadbeat disturbance observer performs control to reduce the vibration of the motor by compensating for the vibrating component or disturbance that the mechanism has. Since the deadbeat disturbance observer has a characteristic of being vulnerable to noise, it is supplemented by moving average filter method to reduce the influence of the noise. Thus, the new controller with the first order deadbeat disturbance observer can perform more robustness and precise the position control for the influence of large inertial load and natural frequency. The simulation stability and efficiency has been obtained through C language and Matlab Simulink. In addition, the experiment of actual 2.5[kW] permanent magnet synchronous motor was verified.