Tuesday, April 24, 2012

Efficiency Optimization Method Based On Radial Basis Function Neural Network In The Induction Motor Drive As A Ship Electrically Powered Propellers

This study developed a method of control of the driving engine / electric-powered propulsion of ships. The driving engine in this study has a propeller Fixed Pitch Propeller (FPP) which is set using the rotation axis induction motor. The method aims to control the speed rotary shaft at the same time optimizing the efficiency of electric motors driving the propulsion load varying.

Efficiency of optimization methods pursued through three major stages. In the first phase done modeling input-output relationship of control systems and stability analysis of electric-powered ship propulsion systems. The analysis showed that the ship propulsion systems based on shaft speed control is a stable system with 30 dB Gain Margin, Phase Margin 80 ° and tolerance Gain additional 34 systems.

In the second stage is designed rotor resistance estimator of induction motors. Estimator is required because of its location on the rotor, can not be measured and its value varies with temperature as an induction motor. This estimator works using information measurements of voltage, stator current and shaft speed. In this study the resulting contribution of adaptive computing to track the actual value of rotor resistance. Adaptive method is used for calculating the position of the rotor flux angle. This strategy can reduce the tracking time span of 1:42 minutes on conventional methods to 3:39 seconds.
In the Three Phase Induction Motors efficiency to be optimized. Efficiency optimization done by regulating the rotor flux. Rotor flux can be set via the d-axis stator current.

Algorithms Neural Nets (ANN) type of Radial Basis Function Neural Network (RBFN) was developed to determine the d-axis stator current optimum. To see the benefits of the method developed, RBFN method is compared with existing models. RBFN method could improve efficiency, particularly at the shaft speed of 3.2 revolutions per second, where the induction motor efficiency can be increased from 26.86% in the conventional method to 62.05% in the RBFN method. Based on the scenario selected trips, on ships 400 DWT, increased efficiency is equivalent to 17 532 kWh of energy savings. Increased efficiency is equivalent to fuel savings and emission reductions Liter 3059.86 6085.36 kg-CO2 gas.

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