• Journal of the Semiconductor & Display Technology
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• v.14 no.3
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• pp.45-50
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• 2015

This paper suggests the sensor-less speed control of PMSM (Permanent Magnet Synchronous Motor) without the position sensor of oil-free air compressor. It estimated d and q axis back electro motive force using Back-EMF (Electro motive Force) observer to control sensor-less speed of PMSM. Also it used the method that tracks the information of rotor position and speed using PLL (Phase Locked Loop) based on estimated d and q axis Back-EMF. The sensor-less speed control of PMSM for oil air compressor application is carried out with the introduced rotor position and speed tracking method. In this paper, the experimental characterization of the sensor-less drive is provided to verify the accuracy of the estimated position and the performance of sensor-less control is analyzed by results obtained from the experiment. Moreover, the potential of PMSM sensor-less drive in industrial application such as compressor drive is also examined.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.503-504
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• 2015

This paper deals with the analysis of characteristics of position and speed estimator of an adaptive sensorless control algorithm for PMSM drives. The analysis shows that the back emf constant variation results in the position estimation error, but does not the speed estimation error. The simulation and experimental results are shown to verify the analysis result and the usefulness of the back emf constant estimator.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1132-1134
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• 2005

This paper presents a design strategy of Slotless type BLDC motor using the space harmonic field method. The distribution of Back emf and torque are considered by movement of the Permanent Magnet and armature current. The result of magnetic field distribution, back-emf, and torque are in agreement with FEM.

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.99.1-99.1
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• 2008

• Journal of Industrial Technology
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• v.29 no.B
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• pp.165-171
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• 2009

This paper proposes a sensorless control method of BLDC motors using line-to-line back-EMFs. Typical sensorless control methods have various problems such as the difficulty in operation at low speed and difficulties in application and so forth. However, the control method using line-to-line back-EMFs that this paper proposes solved not only such problems but also problems of noise and difficulty of commutation detection. The method is to divide line-to-line back EMF into the constant. With 550[W] BLDC motor driving system, simulations and experiments have been carried out for the verification of the proposed control method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.8-15
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• 2019

The PM synchronous motor drives with vector control have been applied to wide fields of industry applications due to its high efficiency. The rotor position information for vector control of a PM synchronous motor is detected from the rotor position sensors or rotor position estimators. The sensorless control based on the mathematical model of PM synchronous motor is generally used and it can be classified into back EMF -based sensorless control and magnet flux-based sensorless control. The rotor position estimating performance of the back EMF-based sensorless control is deteriorated at low speeds since the magnitude of back EMF is proportional to the motor speed. The magnitude of the magnet flux for estimating rotor position in the flux-based sensorless control is independent on the motor speed so that the estimating performance is excellent for wide speed ranges. However, the estimation performance of the model-based sensorless control may be influenced by the motor parameter variation since the rotor position estimator uses the mathematical model of the PM synchronous motor. In this paper, the rotor position estimation performance for the back EMF based- and flux-based sensorless controls is analyzed theoretically and is compared through the simulation and experiment when the motor parameters including stator resistance and inductance are varied.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.2B no.4
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• pp.162-167
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• 2002

This paper presents the dynamic analysis method for a slotless permanent magnet linear synchronous motor (PMLSM) using the 3-D space harmonic method. Instantaneous emf and thrust are considered by movement of the PM and instantaneous armature current instead of $K_E$ (back-emf constant) and $K_F$(thrust force constant) for accurate results. The results of magnetic field distribution, back-emf, inductance, and thrust are in agreement with 2-D FEM and experimental results. To confirm the validity of this method, the calculated results are compared to measured ones.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.2
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• pp.152-161
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• 2011

An interior permanent magnet synchronous motor(IPMSM) has been applied to the electric vehicle due to its high efficiency, compact volume, and wide operating speed ranges. This paper presents the analysis of the flux weakening operating regions at high speeds for the IPMSM that has back emf harmonics. The effect of the back emf harmonics on the motor speed and the maximum torque is analyzed. Also the dq currents for maximum torque operation under the voltage and the current limit conditions are analyzed. The conventional analysis and the presented analysis for the flux weakening operating regions are compared and the maximum torque - speeds characteristics for both analysis are verified through the experiment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.11
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• pp.1584-1590
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• 2017

This paper presents a implementation method of reliable speed limitation controller considering motor parameter variation in high speed operation. In spinning process of drum washing machine, speed increase has to be limited when unallowable imbalance mass is detected. Otherwise, severe noise and vibration can happen because noise and vibration are proportional to imbalance mass. To detect imbalance mass, d-axis current magnitude is used. However, we have to compensate for back-emf and power supply variation by means of detecting them because d-axis current is affected by both of them. On the other hand, we have to carefully estimate back-emf because back-emf is affected by stator resistance variation and inverter voltage error. Stator resistance variation can happen by manufacturing process for mass production or temperature variation in running. And there are inverter voltage errors between command voltage from micro-computer to inverter and real voltage from inverter to motor because of rising and falling time delay and turn-on resistance of power semiconductor switch. To solve this problem, we propose 2-step align current injection method which is to inject step-wise current right before starting. By this method, we can simply obtain stator resistance by ratio of voltage without inverter voltage error and current, and we can measure inverter voltage error. So we can obtain more exact model current, and then by simple calculation with compensation gain, we can estimate more accurate motor back-emf. We show that this method works well. It is verified through experiments.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.1
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• pp.65-71
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• 2006

In this paper, a novel motor control method is proposed to improve the performance of sensorless drive of BLDC motors. In the terminal voltage sensing method, which is a great portion of sensorless control, a precise rotor position cannot be obtained when excessive input is applied to the drive during synchronous operation mode. Especially in the transient state, the response characteristic decreases. To cope with this problem, the unknown input (back-EMF) is modelled as the additional state of system in this paper. Taking into account the disturbance adopted by the back-EMF, the observer can be obtained by the augmented system equation. An algorithm to detect the back-EMF of the BLDC motor using the state observer is constructed. As a result, the novel sensorless drive of BLDC motors that can strictly estimate rotor position and speed is proposed.