Abstract:
This document is a master of engineering thesis prepared for the University of Auckland in the end of the second semester of ME research. This thesis presents findings of a development of an induction cooker system and its detailed experimental results. The working of induction cooker is based on the principles of electromagnetic induction, skin effect and eddy current generation. The developed system demonstrates an innovative control mechanism which drives the IGBT switch to maintain the temperature of the workpiece at specified levels. The concept is termed as “Automatic Temperature Control”. With the temperature controlled mechanism system is designed to heat the workpiece in order to maintain its temperature at two different values for the time and temperature specified by the operator. The proposed control mode can be regarded as an automatic cooker and keep warm function. A user interface is developed to provide the user to SET, ENTER the values and START/STOP the cooker. The system incorporates an LCD to display information of timers, temperature values, status and also information of important system parameters allowing better user interface. The features of Pan Detection, Current Detection, Fan Control and Protection Circuits are developed in the prototype using analog designing and micro-controller programming. The development of prototype is presented and experimental result are discussed and evaluated. A quasi resonant inverter was designed for the system. Simulation results of the quasi-resonant inverter topology and control system are presented using LT SPICE software. A PIC18F45K22 micro-controller by Micro-chip programmed and debugged using MPLABXIDE V 1.8 and ICD 3 is used for designing the digital system. The principle/logic and flow charts for the system’s software development are discussed. The design of PCB layout for the prototype was completed using ALTIUM Designer. The system is tested for its working and the experimental results for the “Automatic Temperature control” mode and other developed features are presented. The development of the induction cooker system incorporating the proposed temperature controlled mechanism was accomplished. The design and experimental results for Current Detection, Pan Detection, IGBT Protection and Automatic Fan Control were achieved. The system can satisfactorily heat the workpiece and also maintain its temperature exactly at the specified levels.