Design of High-Order Phase-Lock loops Controller using Simulink

Phase-Locked Loops (PLLs) have developed into many other electrical, instrument control and electronic systems. Inattentive of their individual implementation, with their related specific problems, the basic theory common to all PLLs is not easy to understanding. Fundamentally, this is because it is feedback system and exhibits an intrinsic nonlinear nature. Even assuming approximate linear model, analysis and subsequent design, of any higher-order( above two ) PLL is challenging. To make things even more difficult, the literature on PLLs is plagued with some misconceptions which have perpetuated for years. Among these misconceptions are the use of parameters to characterise the PLL which are meaningless for higher-order PLLs, such as the loop filter (LF) classifications (passive as opposed to active ) that do not make sense today in implementations dominated by charge pump (CP) topologies, and the confusion of order and type [1]. The accurate analysis of third-order phase-locked loops (PLLs) , those including a second-order loop filter (LF) , is normally eluded because it is very complex. The goal of this paper however, is to propose an alternative approach to the intuitive and analytic design of third -, and even fourth-order loops, as a natural extension of second-order PLL. The approach will also be seen as related to the extension of a conventional PLL (second order) with the so called “aided acquisition” loops [2]. The concepts shown here are general , but of particular interest in applications where the PLL need to operated in a wide hold range, i.e., not a small fraction of the free running frequency (FRF) of the oscillator. The design and constructional features of the whole system are presented in this paper. Experimental work has been carried out on the induction heating system to measure the operation performance under various loading conditions. Experimental results indicate that the operates successfully with a power factor very closed to unity. A simulation model has been develop using Simulink , which has been used to analyse and design the PLL control system. A mathematical model of the system has also been developed in discrete time, with which the stability of the system can be assessed.