Analytical determination of the electromechanical system starting process efficiency index with regard to the distributed nature of input products consumption

Valerii Tytiuk

doi:10.15587/1729-4061.2016.83203

Abstract

Currently, an approach based on the lumped-parameter resource consumption model is used to determine the starting process efficiency index. This is due to the simplicity of analytical expressions for the efficiency index. In actual practice, the resource consumption of the starting process is time-phased in nature, which may lead to biased estimates of the efficiency index and inaccurate operation of the optimization system. In the paper, the actual form of the signal of the cost estimate of input products over time was determined using mathematical modeling of the controlled start system. It is proposed to use a fractional rational function to approximate these signals. The parameters of this approximation at different values of the control action were obtained using the Matlab Curve Fitting Toolbox. The analytical expressions for determining the resource consumption, potential effect and efficiency index of the starting process were obtained on the basis of the proposed approximation. It was found that the position of the maximum efficiency index on the x-axis, obtained when using the lumped-parameter and distributed-parameter starting operation models varies slightly (within the 5 % margin of error). This will reasonably facilitate hardware implementation of optimal control systems of starting processes through the application of the lumped-parameter starting operation model.

Highlights

Starting processes of systems implemented without the use of special engineering solutions have an extreme impact on them
We demonstrate a geometric interpretation of the flow of consumption of input resources in the distributed-parameter starting process model, Fig. 6
The requirements for the approximating function structure, which were the basis for selecting the approximation

Summary

Introduction

Starting processes of systems implemented without the use of special engineering solutions have an extreme impact on them. This provision is common, system-wide, and occurs in various fields of engineering. Direct-on-line starting of a powerful synchronous motor is equivalent to 500 hours of its normal operation [1]. In order to reduce these losses, special starting systems that allow reducing shock loads to an acceptable level are developed. The processes of starting an electromechanical system (EMS) are accompanied by peak power consumption, significant influence on the service life of electromechanical and processing equipment. Especially in commensurable capacity power supply networks, has a significant impact on a mains supply [2].

Objectives

Discussion

Conclusion