• Journal of Power System Engineering
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• v.5 no.3
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• pp.104-113
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• 2001

This paper describes a precise position synchronous control of two axes rotating system using BLDC motors and a cooperative control based on decoupling technique and PI control law. The system is required performances both good speed following and minimum position synchronous errors simultaneously. To accomplish these goals, the three kinds of controllers are designed. At first, the current and speed controller are designed very simply to compensate the influences of disturbances and to follow up speed references quickly. Especially, the two degree of freedom PI controller is used considering both good tracking for speed reference input and quick rejection of disturbances in speed controller. Finally, a position synchronous controller is designed as a simple proportional controller to minimize position synchronous errors. The validity of the proposed method is confirmed through some numerical simulations. Moreover, the results are compared to the conventional master-slave control ones to show the effectiveness of the proposed system.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.2
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• pp.135-140
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• 2010

This paper presents a sensorless speed control of BLDC Motor using terminal voltage of the one phase. Rotor position information is extracted by indirectly sensing the back EMF from only one of the three terminal voltages for a three-phase BLDC motor. Depending on the terminal voltage sensing rotor position, active filter is used for position information. This leads to a significant reduction in the component device of the sensorless circuit. Therefore this is a advantage for the cost saving and size reduction. With indirect sensing methods based on detection of the terminal voltage that require active filtering, the position information needs the six divider section by PLL circuit, the binary counter and johnson counter by the EPLD. Finally, this algorithm can estimate the rotor position information similar to Hall-sensor sticked the three-phase BLDC motor. As a result, the method described that it is not sensitive to filtering delays, allowing the motor to achieve a good performance over a wide speed range. In addition, a simple starting method and a speed estimation approach are also proposed. Experimental and simulation results are included to verify the proposed scheme.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.4-9
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• 1999

A new control method for precision robust position control of a brushless DC (BLDC) motor using asymptotically stable adaptive load torque observer is presented in the paper. Precision position control is obtained for the BLDC motor system approximately linearized using the field-orientation method Recently, many of these drive systems use BLDC motors to avoid backlashe. However, the disadvantages of the motor are high cost and complex control because of nonlinear characteristics. Also, the load torque disturbance directly affects the motor shaft. The application of the load torque observer is published in [1] using fixed gain. However, the motor flux linkage is not exactly known for a load torque observer. There is the problem of uncertainty to obtain very high precision position control. Therefore a model reference adaptive observer is considered to overcome the problem of unknown parameter and torque disturbance in this paper. The system stability analysis is carried out using Lyapunov stability theorem. As a result, asymptotically stable observe gain can be obtained without affecting the overall system response. The load disturbance detected by the asymptotically stable adaptive observer is compensated by feedforwarding the equivalent current which gives fast response. The experimenta results are presented in the paper.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.6
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• pp.445-454
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• 2002

Torque ripple control of brushless DC motors has been the persisting issue of the servo drive systems in which the speed fluctuation, vibration and acoustic noise should be minimized. In this paper, a novel approach to achieve the ripple-free torque control with maximum efficiency based on the d-q reference frame is presented and analyzed. The proposed approach can provide the optimized phase current waveforms over wide speed range incorporating cogging torque compensation without an access to the neutral point of the motor windings. Moreover, the undesirable errors caused by the assumptions such as 3 phase balance or symmetry of the phase back EMF between electrical cycles, which are related with the manufacturing imperfections, can be also eliminated. As a result, the proposed approach provides a simple and clear way to obtain the optimal motor excitation currents. A hysteresis current control system is employed to produce high-frequency electromagnetic torque ripples for compensation. The validity and applicability of the proposed control scheme to real situations are verified through the simulations and experimental results.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.6
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• pp.597-604
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• 2016

In this paper, we develope a speed control system of a BLDC motor for handpieces used in beauty applications. To reduce implementation cost, the control system utilizes hall sensors embedded in BLDC motors for speed estimation. The developed power module of a motor uses only 220V home voltage, so that the control system does not need any other power sources. An over-speed limit controller is also developed to slow down a motor when the speed goes up rapidly for a moment upon some heavy load is removed. The control system is designed to operate a handpiece with speed in the range of 5,000~30,000 RPM. Experiment results show the validity of the developed system, which maintains the speed of a motor steady even though a load is varied.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.1
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• pp.63-69
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• 2008

The position of stator is essential when a trapezoidal BLDC motor is drived. In this paper we proposed a novel sensorless drive system for the trapezoidal BLDC motor without hall sensors or encoders. The resistor Y-connecting method is used to obtain Back-emf of a trapezoidal BLDC motor. Especially, by using the new Back-emf filter circuit proposed in this paper the sensorless characteristic in low speed is improved. The prototype proposed system applied for a 100[W] rating BLDC motor is made and the propriety of the Back-EMF filter circuit is also verified.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.4
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• pp.277-284
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• 2007

This paper describes independent phase BLDC motor with a maximum torque among BLDC motor used for electric propulsion system Independent phase BLDC motor has characteristic that phases of stator we independent electrically. This paper is modeling two type of 3 phases BLDC motors, one has Y-connection type and the other has independent type, and it shows simulation of them, compares its characteristics. As a result of simulation, phase voltage of independent 3 phase BLDC motor is higher than Y-connection three phase BLDC motor. When the stator resistance and inductance are stable, high phase voltage causes an increase in maximum phase current and an increases in it serially causes an increase of maximum torque. It is also found that the current pulsation of independent phase BLDC motor was decreased by controlling phase current of independent BLDC motor.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.9
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• pp.4083-4094
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• 2011

The Electric Power Steering (EPS) has been applied to the vehicles due to its better fuel efficiency, better steering feel, and the compact volume compared to the hydraulic power steering. The brushed PM (Permanent Magnet) DC motors had been adopted in most of the EPS systems until several years ago due to its easy control and a simple hardware configuration of the power converter, but nowadays the BLAC (Brushless AC) motor is becoming more popular for the EPS system because of its high efficiency and long lifetime. This paper reviews the configuration of the EPS system and the BLAC motor and drive technologies based on the papers published recently. The torque ripple reduction for steering feel and the fault detection algorithms for safety are also reviewed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.6
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• pp.1039-1046
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• 2007

This paper presents the analysis for power consumption, mechanical vibration and acoustic noise characteristics of the Coreless and Slotless Brushless DC motor in Digital Lightening Processor(DLP) Motor with the Air-Dynamic Bearing. The Coreless BLDC motor has not the stator yoke as well as the stator slot to remove the unbalance force by the interaction between the stator yoke and Air-Dynamic Bearing clearance. The assembling tolerance and the processing error make the air-gap difference between the magnet and the stator yoke .which occurs the unbalanced electro-magnetic force in the Slotless BLDC motor. It imposes the air-dynamic bearing on the disturbance force and makes the Air-Dynamic Bearing vibrated and noised. Also, The attractive force between the magnet and the silicon steel stator yoke increases the power consumption. In this paper, the power consumption, mechanical vibration and acoustic noise of the Coreless BLDC motor and the Slotless BLDC motor with the silicon steel stator yoke are simulated, analyzed, and tested using the manufactured proto-type motors with Air-Dynamic bearing. The simulated and tested results present that the Coreless BLDC motor without the silicon steel stator yoke has the lower mechanical vibration and noise ,and lower power consumption than the Slotless BLDC motor with the silicon steel stator yoke in Digital Lightening Processor Motor with Air-Dynamic Bearing.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.7
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• pp.706-712
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• 2014

The inverters used to drive Brushless DC motors (BLDC) include switching devices such as FETs and the faults in FETs cause severe performance degradation in systems where a BLDC acts as actuator. This paper presents a fault detection and isolation method for the FETs of an inverter for BLDC motor control systems, which is based on the EKF (Extended Kalman filter). Firstly, an equivalent circuit model for a BLDC motor plus its inverter system was derived. Secondly, a state-space equation was established, where the on-resistance of the FETs is expressed as a state variable and the EKF equation estimates the on-resistance. If the estimated resistance differs greatly from the known value, it can be asserted that there is a fault on that FET. Thirdly, the local convergence of the established EKF was proved. Finally, through the experiments, the performance of the proposed method was verified. The results show that the on-resistance is estimated close to the value specified in the FET data sheet in normal operation, whereas the estimated resistance is a much larger value than the normal one in case an FET fault occurs. Therefore, it is confirmed that the proposed fault detection and isolation method works appropriately in real systems.