• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.6
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• pp.855-864
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• 2011

In this paper, a nonlinear controller based on adaptive back-stepping method is proposed for high performance operation of IPMSM(Interior Permanent Magnet Synchronous Motor). First, in order to improve the performance of speed tracking a nonlinear back-stepping controller is designed. Since it is difficult to control the high performance driving without considering parameter variation, a parameter estimator is included to adapt to the variation of load torque in real time. In addition, for the efficiency of power consumption of the motor, controller is designed to operate motor with minimum current for maximum torque. The proposed controller is applied through simulation to the a 2-hp IPMSM for the angular velocity reference tracking performance and load torque volatility estimation, and to test the MTPA(Maximum Torque per Ampere) operation in constant torque operation region. The result verifies the efficacy of the proposed controller.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.1
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• pp.35-41
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• 2013

Torque characteristics of a turbopump turbine was analyzed using the turbine performance test result. Specific torque of the subject turbine could be expressed as a linear function of corrected rotor speed at a fixed pressure ratio and it has been confirmed by the test result. It also found that corrected rotor speed-specific torque characteristics does not change anymore if the turbine pressure ratio is set bigger than a certain value. Using the turbine torque characteristics and pyro-starter performance test results, rotational speed development behavior of the turbopump was predicted. Prediction revealed that the lap time reaching 50% of turbopump design speed is less than 0.7 second. Effect of the thermal loss between pyro-starter and turbopump was negligible.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.4-10
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• 2012

Torque characteristics of a 75-tonf turbopump turbine was analyzed using the turbine performance test result. Specific torque of the subject turbine could be expressed as a linear function of corrected rotor speed at a fixed pressure ratio and it has been confirmed by the test result. It also found that corrected rotor speed-specific torque characteristics does not change anymore if the turbine pressure ratio is set bigger than a certain value. Using the turbine torque characteristics and pyro-starter performance test results, rotational speed development behavior of the turbopump was predicted. Prediction revealed that the lap time reaching 50% of turbopump design speed is less than 0.7 second. Effect of the thermal loss between pyro-starter and turbopump was negligible.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.5
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• pp.845-850
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• 2021

In this study, the energy conversion characteristics and design of electric vehicle (EV: Electric Vehicle) powertrain were performed. An interior permanent magnet synchronous motor (IPMSM) was targeted as a power source for the EV powertrain, and control was performed. In order to drive the IPMSM, two regions are considered: a constant torque and a constant output (field-weakening) region. The design of the control system for IPMSM was constructed based on the d-q reference frame (vector control). To determine the static characteristics of motor torque appearing in two areas of IPMSM, a torque control system and a d axis current control system of IPMSM were implemented and proposed. Matlab-Simulink software was used for characteristic analysis. Finally, by applying IPMSM to the powertrain model under the actual EV vehicle level conditions, simulation results of the proposed control system were performed and characteristics were analyzed.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.3
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• pp.297-302
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• 2002

The direct torque control(DTC) of induction machines has the advantages of a simple control scheme and a very quick and robust torque response and its application is extended in the traction field. However, some drawbacks of the conventional DTC strategy using a hysteresis controller are the relatively large torque ripple in the steady state and the variation of switching frequency according to the amplitude of hysteresis bands and the motor operating conditions. In this paper, a navel direct t()roue control scheme of induction machines based on stator flux control and Space Vector Modulation Is proposed to acquire the advantage of a fixed switching period and the minimization of the torque and stator current ripple in a wide speed range. The effect of proposed method has been proven by simulations and experiments.

• Journal of the Korean Society for Railway
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• v.15 no.2
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• pp.129-134
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• 2012

In this paper, speed control of IPMSM drives for the next generation domestic high speed railway system using NPC 3-level inverters is presented. The NPC multilevel inverter is suitable for the high-voltage and high-power motor drive system because it has advantages in that the voltage rating of the power semiconductor devices and output current harmonics are reduced. For the speed control of IPMSM using NPC 3-level inverters, maximum torque control is applied in the constant torque region, and filed weakening control is applied in the constant power region. Simulation programs based on MATLAB/Simulink are developed. Finally the designed system is verified and their characteristics are analyzed by the simulation results.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.3
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• pp.231-237
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• 2007

The torque ripple of the hydraulic pumps for the Electro-hydrostatic Actuators can disturb the cylinder position control under slewing speed operation condition. In principle, the periodic change of the reaction torque generated by a piston type pump is highly dependent on the waveform of its cylinder chamber pressure. In case of uni-directional pumps operating at constant speed, the transient overshoot and rising slope of the cylinder pressure can be adjusted by the precompression angle and notch shape of their valve plates. Therefore, the influence of the valve plate geometry on the torque ripple magnitude of a bent-axis type piston pump for EHA application was investigated in this study. The results showed that any improvement of the torque ripple of such a bi-directional pump can not be achieved by modifying the valve plate geometry, regardless of its operation speed.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.1
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• pp.56-63
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• 2003

This paper studies that torque model considered with decaying phase back-EMF is different In conduction and commutation period and analyzes the torque pulsation components mathematically. In this paper, it is proposed a novel method to suppress torque pulsation due to commutation time. First, it propose commutation delay time control method, which is to compensate current slope of rising phase and decaying phase to control commutation time. Current ripple is minimized at non-commutating current and torque ripple is reduced below critical speed range that dc link voltage is the same as four times of back-EMF voltage. However, torque ripple still exists due to the relation with back-EMF and commutating current and it is increased on a large scale above critical speed range, especially. Secondly, proposed method is commutation time control, which is considered with torque pulsation due to the relation of back-EMF and commutating current. Through the proposed method, the torque pulsation can be minimized in the whole speed range as well as range over critical speed.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.274-275
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• 2017

부스트-인버터 시스템에서 6-스텝 시 토크 리플을 줄이기 위한 방법을 제시한다. 모델 기반의 전압 방정식을 통해 필요한 직류단 전압의 크기 및 위상을 구하고 전류 전향 보상을 통해 전압을 합성한다. 이를 통해 직류단 캐패시턴스를 수 ${\mu}F$까지 낮출 수 있어 캐패시터의 부피 및 비용을 절감할 수 있다. 이러한 최적 해 운전 시 생기는 입력 파워 리플의 문제점을 해결하기 위한 일정 파워 공급 방법을 제시하며 이를 통해 운전영역에 따른 적절한 운전 방법의 선택을 제시한다.

• Journal of the Korean Society for Railway
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• v.13 no.5
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• pp.493-499
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• 2010

The next generation domestic high speed railway system is a power dispersed type and uses vector control method for motor speed control. Nowadays, inverter driven induction motor system is widely used. However, recently PMSM drives are deeply considered as a alternative candidate instead of an induction motor driven system due to their advantages in efficiency, noise reduction and maintenance. In this paper, the maximum torque control approach is presented for the IPMSM drives with reluctance torque. The applied control method uses maximum torque control per ampere technique. Simulation programs based on Matlab/Simulink are developed. Finally the designed system is verified by simulation and their characteristics are analyzed by the simulation results.