Page 173 - 2023-Vol19-Issue2

Received: 28 April 2023 | Revised: 1 July 2023 | Accepted: 1 July 2023

DOI: 10.37917/ijeee.19.2.19 Vol. 19 | Issue 2 | December 2023

Open Access

Iraqi Journal for Electrical and Electronic Engineering

Original Article

Design of PLL Controller for Resonant Frequency

Tracking of Five-Level Inverter Used for Induction

Heating Applications

Aws H. Al-Jrew*1,2, Jawad R. Mahmood1, Ramzy S. Ali1
1Electrical Engineering Department, University of Basrah, Basrah,
2Electronic and Communications Engineering Department, Al Muthanna University, Muthanna, Iraq

Correspondance
*Aws H. Al-Jrew
Electronic and Communications Engineering Department,
Al Muthanna University, Muthanna, Iraq
Email: aws.hashim@mu.edu.iq

Abstract
In this work, the phase lock loop PLL-based controller has been adopted for tracking the resonant frequency to achieve
maximum power transfer between the power source and the resonant load. The soft switching approach has been
obtained to reduce switching losses and improve the overall efficiency of the induction heating system. The jury’s stability
test has been used to evaluate the system’s stability. In this article, a multilevel inverter has been used with a series
resonant load for an induction heating system to clarify the effectiveness of using it over the conventional full-bridge
inverter used for induction heating purposes. Reduced switches five-level inverter has been implemented to minimize
switching losses, the number of drive circuits, and the control circuit’s complexity. A comparison has been made between
the conventional induction heating system with full bridge inverter and the induction heating system with five level
inverter in terms of overall efficiency and total harmonic distortion THD. MATLAB/ SIMULINK has been used for
modeling and analysis. The mathematical analysis associated with simulation results shows that the proposed topology
and control system performs well.

Keywords
Induction Heating (IH), Phase Lock Loop (PLL), Resonant Series Inverter, Zero Voltage Switching (ZVS)..

I. INTRODUCTION classical topologies such as half-bridge and full-bridge invert-
ers as a power supply for the induction heating system [5–8].
Induction heating is a technology used for heating metals or The use of classical topologies for inverters in medium volt-
any conductive materials. It is used especially in industrial age applications with two or four switches will increase the
operations such as surface hardening, welding, tempering, stress on switches, and then increased the losses as well [9].
brazing, and some home appliances like induction stoves or From this point, the need to use a multilevel inverter in such
induction water heaters [1]. high frequency application is required. The use of reduced
switches multilevel inverter will reduce the complexity of
Induction heaters have become popular due to their fast driver circuit then cost saving [10].
heating durations, ability to heat a specific area, environmen-
tally friendly, more efficient, safe, and saving energy [2, 3]. Because of resonant condition reached in such induction
heating system, these types of inverters with high switching
The power source designed for induction heating should frequency can be categorized as resonant inverters. The most
be cost-effective and work better, so many studies have been common topologies for high-frequency resonant power con-
conducted to improve the power semiconductor switching
devices and microprocessors [4]. Many previous works used

This is an open-access article under the terms of the Creative Commons Attribution License,
which permits use, distribution, and reproduction in any medium, provided the original work is properly cited.
©2023 The Authors.
Published by Iraqi Journal for Electrical and Electronic Engineering | College of Engineering, University of Basrah.

https://doi.org/10.37917/ijeee.19.2.19 |https://www.ijeee.edu.iq 169