Comparison of PID Controller with Model Predictive Controller for Milk Pasteurization Process

Tesfaye Alamirew,Nigus Gabbeye,V Balaji

doi:10.11591/eei.v6i1.575

Tesfaye Alamirew, Nigus Gabbeye + Show 1 more

Open Access

https://doi.org/10.11591/eei.v6i1.575

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Abstract

Proportional–Integral–Derivative (PID) controllers are used in many of the Industries for various process control applications. PID controller yields a long settling time and overshoot which is not good for the process control applications. PID is not suitable for many of the complex process control applications. This research paper is about developing a better type of controller, known as MPC (Model Predictive Control). The aim of the paper is to design MPC and PID for a pasteurization process. In this manuscript comparison of PID controller with MPC is made and the responses are presented. MPC is an advanced control strategy that uses the internal dynamic model of the process and a history of past control moves and a combination of many different technologies to predict the future plant output. The dynamics of the pasteurization process was estimated by using system identification from the experimental data. The quality of different model structures was checked using best fit with data validation, residual and stability analysis. Auto-regressive with exogenous input (ARX322) model was chosen as a model structure of the pasteurization process and fits about 80.37% with datavalidation. MPC and PID control strategies were designed using ARX322 model structure. The controller performance was compared based on settling time, percent of overshoot and stability analysis and the results are presented.

Highlights

In a modern world the economic and quality issues become more and more important, efficient control systems have become indispensable
The pasteurization process consists of three stages like regeneration, heating and cooling sections
From the above results and discussion we identified the best controller for pasteurization process to be MPC

Summary

Introduction

In a modern world the economic and quality issues become more and more important, efficient control systems have become indispensable. The process industries require more reliable, accurate, robust, efficient and flexible control systems for the operation of process plant. In order to fulfill the above requirements there is a continuing need for research on improved forms of control [1]. Control of temperature plays an important role in pasteurization plants. High temperature short time (HTST) is keeping milk or other food stuffs at 72 0C for 15 seconds in insulated holding tube. The pasteurization process consists of three stages like regeneration, heating and cooling sections. The crucial stage is heating process using heat exchanger to ensure unpasteurized product achieve desired pasteurization temperature before pass through holding tube and cooling sections. Prior to pasteurize milk sample, the equipment must have adequate controller to control the outlet temperature in order to maintain at standard value [2]

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