• 한국소음진동공학회논문집
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• 제25권6호
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• pp.414-419
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• 2015

Recently, commercial ships and other specialized vessels with electric propulsion system employ variable speed induction motor as its prime mover. The wide application of electrical motors also includes being the main drive system in most industrial machineries. However, during its start-up, shutdown, and brake switch operation, excessive torque variation are generated. As such, flexible coupling are installed in order to reduce the transmitted torque fluctuation to the driven side. In this paper, the pulse torque generated by an variable speed induction motor was analyzed theoretically and through measurement of torsional vibration. Induction motor with inverter on marine propulsion system and industrial compressor were used as experimental subjects. The study confirmed that pulse torque are generated regardless of motor speed and interpreted as a vibration source of the whole system. Results presented herein can be adopted as the basis in future amendment of inspection classifying body regulations.

• 동력기계공학회지
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• 제13권6호
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• pp.57-62
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• 2009

Unsteady flows in a semi-induction system was investigated to verify their characteristics. A semi-induction system was designed and made to verify the Sow characteristics in an intake system. To attain an intact wave of an intake pulse, a single semi-intake system was adopted as a test rig. The system consists of an intake pipe and a rotary valve as a pulse generator, and a variable volume Helmholtz resonator. The variable volume Helmholtz resonator was mounted in the intake pipe to enhance a breathing capacity and engine performance. The phase and amplitude of the pulsating flow in an unsteady flow system were found to affect the charging capacity significantly. The behavior of pressure wave, their phase and amplitude were investigated in various regions. Some of the results obtained from experiments were described.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.611-613
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• 2004

This paper is concerned with the simulation and determination of the input voltage and frequency for the optimal efficiency operation of induction motors. In general, induction motors have a specific character that operation efficiency is dropped sharply at the light roads condition. Consequently, if the induction motor is controlled by high efficiency using the VVVF(variable voltage variable frequency) control methods at optimal values, the entire system can obtain the substantial energy savings from the efficiency improvement in induction motors. In this paper, optimal slip is derived from the modeling of an induction motor and the optimal hybrid-control method is suggested by the simulation of the proposed algorithm for a 3-phase induction motor.

• 동력기계공학회지
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• 제10권1호
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• pp.12-18
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• 2006

A three-degree of freedom model of intake system was contrived and investigated in various ways for the purpose of the amelioration of the volumetric efficiency in a low and transient engine speed for a multi cylinder diesel engine. The basic concept beyond this model started from the theory that each degree of freedom model has volumetric efficiency peak as many as its number of the degree of freedom. The volumetric efficiency affects significantly to the engine performance; torque characteristics, fuel economy and emission level. For commercial vehicles and stationary engines, the engine is designed so as to produce their best performance near the normal engine speeds, thus the low engine speed area has a tendency of poor volumetric efficiency. The aim of this study was highlighted on the amelioration of volumetric efficiency of low engine speed area in a multi cylinder diesel engine matched with an additional Helmholtz resonator. By the use of VIS(variable induction system) volumetric efficiency at low engine speed range was significantly improved. The availability of control by combination of VIS and CIS(conventional induction system) will be proposed as a variable induction system that would be an appropriate model for amelioration of the volumetric efficiency at low engine speed.

• 대한전기학회논문지
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• 제38권2호
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• pp.93-99
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• 1989

This paper describes Sinusoidal Wave-Variable Voltage Variable Fequency (SW-VVVF) system for the high efficiency drive of a 3-phase induction motor. SW-VVVF system consists of a 3-phase 24-pulse converter and a SPWM inverter. The converter with additional 2 tap diode circuits in interphase reactor reduces harmonics in input current. The SPWM inverter consists of an improved PLL system and a V/F controller, which reduces harmonics in output current and performs a high efficiency algorithm by maintaining a constant slip frequency and compensating for the velocity variation of the induction motor with the change of load. Therefore, this system reduces harmonics in input and output currents, and also can drive an induction motor with high efficiency in an economical way. We have proved its utility through experiment.

• Journal of Power Electronics
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• 제8권3호
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• pp.268-274
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• 2008

This paper presents a proposed position controller for a vector controlled induction motor. The position controller design depends on the rotational motion equations and a classical speed controller (CSC) performance. The CSC is designed to have the ability to track variable reference inputs and to provide a predefined system performance. Standard position controller in industry is presented to analyze its performance and its drawbacks. Then the proposed position controller is designed, based on the well defined rotational motion equations. The proposed position controller and the CSC are applied to control the position and speed of the vector controlled induction motor with different ratings. Simulation results at different operating conditions are presented to evaluate the proposed controllers' performance. The results show that the CSC can drive the motor with a predefined speed performance and can track a variable reference speed with an approximately zero steady state error. The results also show that the proposed position controller has the ability to effect high-precision positioning in a limited time and to track a variable reference position with a zero steady state error.

• Journal of Power Electronics
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• 제5권4호
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• pp.289-304
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• 2005

This paper describes a simple control structure and power conditioning system for an indirect vector controlled stand-alone induction generator (IG) used to operate under variable speed. The required reactive power for the IG system is supplied by means of a capacitor bank and a voltage-source PWM converter. Using a capacitor bank to transfer the reactive power to the IG under the rated speed and no-load conditions starts the IG operation and reduces the PWM converter size. The vector control structure for the variable speed IG power conditioning system compensates for changes in the electrical three-phase and DC loads while considering the magnetizing curve of the IG. The vector control structure is developed to regulate the DC link voltage of the PWM converter and the IG output voltage. The experimental and simulated performance results of the IG power conditioning system at various speeds and loads are given and show that this proposed scheme can be used efficiently for a variable speed, wind energy conversion system.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.469-471
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• 2005

Wind farms employs induction generators which are two type, one is Squirrel cage for fixed speed wind turbines and the other is Wound induction generator (doubly fed induction generator DFIG) for variable speed wind turbines. this paper describes grid connection scheme of wind power system using two type induction generators and simulation results show the characteristics of two type induction generators.

• 조명전기설비학회논문지
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• 제29권7호
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• pp.38-46
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• 2015

This paper propose a variable parameter estimations for variable over current load of five-phase squirrel-cage induction motor(IM) to servo control system. In order to high performance control of AC motor using a field oriented control(FOC) and direct torque control(DTC) algorithm, there are required precise motor parameters for slip calculation, flux observer, controller gain, torque command of current components, rotor position, speed estimation, and so on. We are suggest a analyzed estimation results of the motor parameters that developing five-phase squirrel-cage IM have a stator of concentrated winding for experimental within variable over current load at rated input frequency. There are results of stator winding measurement, no-load test, locked-rotor test, variable over current load test, and estimated parameters of equivalent circuits using manufactured experimental apparatus by IEEE Standard Test Procedure for Polyphase Induction Motors and Generators 112-2004.

• 전기학회논문지P
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• 제63권4호
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• pp.241-247
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• 2014

This paper propose a variable parameter estimations of five-phase squirrel-cage induction motor(IM) for speed control system. In order to high performance control of AC motor using a field oriented control(FOC) and direct torque control(DTC) algorithm, there are required precise motor parameters for slip calculation, flux observer, controller gain, rotor position, speed estimation, and so on. We are suggest a analyzed estimation results of the motor parameters that developing five-phase squirrel-cage IM have a stator of concentrated winding for experimental of variable input power frequency. There are results of stator winding test, no-load test, locked-rotor test, variable actual load test, and estimated parameters of equivalent circuits using manufactured experimental apparatus by IEEE Standard Test Procedure for Polyphase Induction Motors and Generators 112-2004.