• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.7
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• pp.491-500
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• 2004

This paper considers a hybrid PWM(pulse width modulation) method which can be used in the brushless DC motor controller. Due to many disadvantages of bipolar PWM method, unipolar PWM method is mostly used in industrial field. In constant speed control application, the unipolar PWM method shows the good performance of speed control. But in the wide range of speed control application, it shows poor performance especially when deceleration is needed. So we propose the hybrid PWM method that utilizes both of bipolar and unipolar PWM methods according to the sign of the speed controller output. Simulation and experimental result show that the proposed method improves speed control performance of the brushless DC motor which is applied to the industrial sewing machines.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.105-107
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• 2005

A high-speed brushless DC motor for a 50-kW, 70-krpm turbo-compressor was developed based on a 2-D analytical method, of which design was verified using the FE analysis. A prototype machine was also fabricated and tested to confirm the analytical design. Preliminarily obtained experimental data using the prototype machine shows the validity of the analytical approach.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.379-381
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• 1999

This paper presents a study of the performance of a brushless DC motor (BLDCM) speed control system. Recently, most motor controls are implemented in digital electronics. Digital controllers tend to be more accurate, less susceptible to noise and more flexible in terms of programming. The system used a digital PI controller in order to implement the constant speed of Brushless DC motor. Microprocessor used in this experiment is 80c196kc. The applied motor has been constructed using a 50W, 150V, 3000rpm, four-pole motor.

• Proceedings of the KIEE Conference
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• 2004.05a
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• pp.19-21
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• 2004

This paper considers pulse width modulation (PWM) methods which are used in 3-phase brushless DC motor controller. Due to many disadvantages of bipolar PWM method, unipolar PWM method is mostly used in industrial field. In constant speed control application, the unipolar PWM method shows a good performance of speed control. But in the wide range of speed control application, it shows a poor performance especially when deceleration is needed. So we propose hybrid PWM method that utilizes two PWM methods according to the sign of speed controller output. The simulation and experimental result shows that the proposed method improves a speed control performance of the brushless DC motor which is applied to industrial sewing machines.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.4
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• pp.62-70
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• 1995

Brushless DC Motor (BDCM) is widely used in the industry such as a variable speed motor in a compressor for room air conditioners, because the motor can be easily controlled and operated over a wide speed range. The system to drive BDCM needs encoder that senses rotor position. Gut in a certain application, the position sensor has to be avoided. In the paper, various position sensorless drive systems for BDCM are investigated and critically evaluated, so that the effective method of sensorless control can be selected. Out of these methods, the freewheeling diode current sensing has many advantages. For example, the simple starting procedure makes it possible to perform sensorless control even in low speed. So the hardware design for this method has been carried out and the system has been implemented using DSP. The experimental results verified that the freewheeling diode current sensing approach has advantages in starting procedure and low speed sensing.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.660-664
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• 2004

The indirect rotor position detection method using terminal voltage of brushless DC motor (BLDCM) requires simple control circuit, and has wide speed range of sensorless operation. However, because the substantial phase difference exists between real back emf and terminal voltage, the existing indirect detection method using analog filter which is affected by frequency, speed, and load sensitively cannot be synchronized with current, in the end, it advances or delays. This paper presents new analog filter circuit design for rotor position estimation in order to solve the problem, and proposes novel sensorless operation method which is stable even in high speed range and not influenced by parameters with analysis on phase difference by load and speed. Moreover, the appropriateness of the proposed sensorless drive in this paper is verified and analyzed by experimentation.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.289-293
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• 2004

The sensorless speed control technique for BLDCM using digital IP control is proposed in this paper for advanced speed characteristic which is robust for loads. The sensorless drive of BLDCM using terminal voltages is affected by load or speed because it uses analog filters to estimate the rotor position. For this reason, the robust speed controller with the accurate rotor position estimator is needed for sensorless control which is robust to load and insensitive to motor parameters. The constant speeds robust to load variation and the stable sensorless control of BLDCM robust to the increase or decrease of speed with constant load are implemented using digital IP control in this paper. The validity to these is established with experimentation.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2534-2536
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• 1999

This paper suggested a new sensorless driving strategy for brushless de motor which can improve the conventional degradation of highspeed operating performances, lowspeed operating performances and starting performances caused by applying general single pwm switching frequency. By varying PWM switching frequency during operating time, the proposed method can get some desired upper performances. For confirming the validity of the proposed method, the sensorless driving system is implemented with an rPM module and 87c196MC micro controller.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.4
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• pp.55-61
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• 1995

Variable structure control (VSC) can be used for the control of power plants required stability and robustness such as elevator control. It has no overshoot and is insensitive to parameter variations and disturbances in the sliding mode where the system structure is changed with the sliding surface in the center. But in the real system, VSC has a high frequency chattering which has a bad influence upon the control system proformances. In this paper, to alleviate the high frequency chattering, a binary controller (BC) with inertial type external loop is implemented by DSP and applied to position control of brushless DC motor. Binary controller has external loop to generate the continuous control input with the flexible variation of primary loop gain. Thus it has the property of chattering alleviation in addition to advantages of the conventional variable structure control.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.585-587
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• 1994

The chattering phenominon is the one of the problems on Variable Structure Controller(VSC). To alleviate this problem, Modified Variable Structure Controller(MVSC) with sliding sector is presented in this paper. This controller is adopted to the position drive system of brushless dc motor. For the simplification of hardware, the current controller also uses the sliding mode control method. Computer simulations are presented to show chattering alleviation of the proposed control scheme.