• Proceedings of the KIEE Conference
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• 2003.10b
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• pp.104-106
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• 2003

In recent years for propulsion of cooling fan in cars are more used electrical motors than the engine direct coupled type. But the electrical motor which is now used has the brush and the commutator. Because of the brush and the commutator the electrical motor has short life time, low efficiency and mechanical- electrical noise. Therefore it is tried to develope brushless dc motor. The motor is located in the hot air from the radiator. The motor temperature increases high and the increasing of the motor temperature rolls big in its character. The cooling fan motor has relative small in size and input voltage is low. For 300 w output power must be the current of the motor high which causes high copper loss. In this paper will be tested and analysed characteristics of a dc motor which is now used for cooling fan and a BLDC motor will be designed with same character of the brushed motor and with considering of improvement of the efficiency. After design the motor should be analysed and tested.

• 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.

• The KSFM Journal of Fluid Machinery
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• v.15 no.2
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• pp.57-62
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• 2012

The constant air volume flow fan can maintain constant flow rate to the wide range of exit pressure. Therefore, the use of this fan is increasing recently for ventilation of high building. Brushless DC motor is adopted to this fan because that has advantages of compactness and performance. But this type of motor protrude from impeller hub side to fan inlet. The Impeller inlet flow is influenced by size of this obstacle called hub. In this paper, the influence of hub shape on the fan performance characteristics are experimentally and numerically analyzed. CFX 12.0 is used to perform the fan internal flow analysis and numerical results are compared with the experiments. Depending on hub shape, internal loss is generated and the performance and efficiency are reduced. The best performance is occurred around $h/b_1$ = 0.25. The results of this study will be contribute to initial design of constant air volume flow fan development.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.10
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• pp.1026-1030
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• 2010

This paper summarizes the activities performed for the development of a BLDC(Brushless Direct Current) motor driven cryogenic thrust control valve with application to KSLV-II rocket engine. The developed thrust control valve can modulate the flow rate of liquid oxygen under cryogenic temperature of 90K and high pressure of 113.2 bar with the help of electro-mechanical actuator driven by a BLDC motor. This valve can be applied to an engine combustion test after minor change because all development certification test have been performed successfully.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.973-974
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• 2011

이 논문은 단상 외전형 브러시리스 모터의 권선 인덕턴스를 해석적인 방법으로 산정하고 실험결과와 비교하였다. 모터의 초기 설계단계에서 사용하는 자기회로해석은 매우 유용하고, 인덕턴스는 자기회로해석에서 중요한 파라미터이다. 회전자계의 영향은 쇄교 자속으로 표현할 수 있고 자속 쇄교수는 인덕턴스에 비례하기 때문이다. 따라서 모터의 특성해석을 위해서 인덕턴스 산정은 매우 중요하다. 해석적인 방법으로 권선 인덕턴스를 산정하였고 회전자의 영향을 무시하였다. 그리고 LCR 미터와 전류 변화법으로 각각 권선 인덕턴스를 측정하였다. 해석값과 전류 변화법으로 측정한 권선 인덕턴스는 비슷하였다. 이 논문에서 제시한 권선 인덕턴스의 해석적인 산정방법은 모터의 초기 설계단계에서 자기회로해석으로 특성을 해석하는 데 도움이 될 것이다.

• Journal of Power Electronics
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• v.11 no.2
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• pp.188-193
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• 2011

A highly efficient AC-DC converter for small wind power generation systems using a brushless DC generator (BLDCG) is presented in this paper. The market standard AC-DC converter for a BLDCG consists of a three-phase diode rectifier and a boost DC-DC converter, which has an IGBT and a fast recovery diode (FRD). This kind of two-stage solution basically suffers from a large amount of conduction loss and the efficiency greatly decreases under a light load, or at a low current, because of the switching devices with a P-N junction. In order to overcome this low efficiency, especially at a low current, a three-phase bridgcless converter consisting of three upper side FRDs and three lower side Super Junction FETs is presented. In the overall operating speed region, including the cut-in speed, the efficiency of the proposed converter is improved by up to 99%. Such a remarkable result is validated and compared with conventional solutions by calculating the power loss based on I-V curves and the switching loss data of the adopted commercial switches and the current waveforms obtained through PSIM simulations.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.212-214
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• 2006

Air Management System is composed by Pump, Fan, Compressor and Blower In general their performances depend on the capability of the motor, power converter device and controller. Especially, it should be noticed upon designing Air Management System using for Fuel Cell System, that Pump, Fan, Compressor and Blower satisfy the condition of the high performance, high efficiency, high density and reasonable price considering the safety and Economic Efficiency. In order for this, it should be studied that which kind of Motor is the most suited for Air Management System for Fuel Cell, such as Induction Motor, Brushless DC Motor, and Switched Reluctance Motor which is widely using in industry. This paper presents the designing and manufacturing of Outer Rotor Type BLDC Motor and Driver for Air Blower of Air Management System. Experimental results from a laboratory prototype arc presented to validate the feasibility of the proposed Air Blower Motor and Driver.

• Journal of Electrical Engineering and Technology
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• v.6 no.2
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• pp.215-225
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• 2011

In this paper, a buck DC-DC bridge converter is used as a power factor correction (PFC) converter for feeding a voltage source inverter (VSI) based permanent magnet brushless DC motor (PMBLDCM) drive. The front end of the PFC converter is a diode bridge rectifier (DBR) fed from single phase AC mains. The PMBLDCM is used to drive the compressor of an air conditioner through a three-phase voltage source inverter (VSI) fed from a variable voltage DC link. The speed of the air conditioner is controlled to conserve energy using a new concept of voltage control at a DC link proportional to the desired speed of the PMBLDC motor. Therefore, VSI operates only as an electronic commutator of the PMBLDCM. The current of the PMBLDCM is controlled by setting the reference voltage at the DC link as a ramp. The proposed PMBLDCM drive with voltage control-based PFC converter was designed and modeled. The performance is simulated in Matlab-Simulink environment for an air conditioner compressor load driven through a 3.75 kW, 1500 rpm PMBLDC motor. To validate the effectiveness of the proposed speed control scheme, the evaluation results demonstrate improved efficiency of the complete drive with the PFC feature in a wide range of speed and input AC voltage.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.9
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• pp.1-7
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• 2014

Brushless Direct Current(BLDC) Motor is essential to measure a rotor position because of that this motor type needs to synchronize the rotor's position and changeover phase current instead of a brush and commutator used on the existing dc motor. Recently, many researches have studied on sensorless control drive for BLDC motor. The conventional control methods are a compensation value dq, Kalman filter, Fuzzy logic, Neurons neural network, and the like. These methods has difficulties of detecting BEMF accurately at low speed because of low BEMF voltage and switching noise. And also, the operation is long and complex. So, it is required a high-performance microprocessor. Therefore, it is not suitable for a small BLDC motor sensorless drive. This paper presents control methods suitable for economic small BLDC motor sensorless drive which are an improved design of the BEMF detection circuit, simplifying a complex algorithm and computation time reduction. The improved motor sensorless drive is verified stability and validity through being designed, manufactured and analyzed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.2
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• pp.92-100
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• 2010

A new class of electronically commutated brushless motor, the flux-switching motor(FSM) is gradually emerging in power tools and household appliances especially fan and pump application because of green policy. This motor offers advantages of high-power density and relatively high efficiency compare with induction motor, low cost and simple motor structure compare with bldc motor. This paper presents the principle of the FSM and design of the 12/6 pole FSM drive system for fan application. Finally, test results of the prototype motor are provided to verify a validity of the fan application with TMS320F2812 DSP and inverter.