State Space Modeling and Simulation for LCC type Resonant Converter

International Journal of Research and Innovation in Applied Science (IJRIAS) | Volume III, Issue II, February 2018 | ISSN 2454-6194

State Space Modeling and Simulation for LCC type Resonant Converter

S. S. Tanavade^#, S. Premachandran

   Department of Electrical and Computer Engineering, Caledonian College of Engineering, Muscat

Abstract- This paper presents state space modeling for a single stage LCC type resonant converter. The converter is designed for high power factor on supply side and minimization of reactive power rating for its resonant components. Quality factor at the peak of AC line for minimum expected value of input voltage is chosen for designing the converter. State Space modeling is used to analyze the converter. Converter operation in a power frequency cycle is split in to eight modes. State variable models are developed for each mode of operation. Time domain operating characteristics of the converter are obtained by using MATLAB simulation.
The output voltage of the converter is regulated using controlling the switching frequency without any active control of AC line current. Ratio of switching frequency to series resonant frequency is required to be kept more than one to maintain lagging power factor mode of operation over majority of the AC cycle. However, the converter operates in leading power factor mode near valleys of line voltage.

Keywords-LCC type resonant converter, quality facto, kVA rating, state space modelling, zero voltage switching

I. INTRODUCTION

Resonant converters are used in many power supply applications. This is because of their higher frequency operation, relatively higher efficiency, smaller size, lighter weight, reduced electromagnetic interference and better dynamic response when compared to their PWM counterpart [1-4].

The series resonant converter (SRC) [4] is only suitable for loads with small variation. SRC is not capable of controlling the output voltage at light loads. Parallel loaded Series Resonant Converter (PLSRC) though naturally short circuit proof has a drawback of poor efficiency at light load condition. The LCC type resonant converter takes on the desirable characteristics of these resonant converters. It can run over a large input voltage range and a large load range while maintaining excellent efficiency. This converter can be operated either in leading power factor operation or lagging power factor operation. The operation in lagging power factor mode results in loss less snubber circuits, elimination of turn on losses in semiconductor devices, reduction in size of reactive components and operation with slow recovery diodes [5]-[16].

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