Digital System Performance Enhancement of a Tent Map-Based ADC for Monitoring Photovoltaic Systems

Philippa Hazell,Peter Mather,Andrew Longstaff,Simon Fletcher

doi:10.3390/electronics9091554

Philippa Hazell, Peter Mather + Show 2 more

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https://doi.org/10.3390/electronics9091554

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Journal: Electronics	Publication Date: Sep 22, 2020
Citations: 2	License type: CC BY 4.0

Affiliation: University of Huddersfield

Abstract

Efficient photovoltaic installations require control systems that detect small signal variations over large measurement ranges. High measurement accuracy requires data acquisition systems with high-resolution analogue-to-digital converters; however, high resolutions and operational speeds generally increase costs. Research has proven low-cost prototyping of non-linear chaotic Tent Map-based analogue-to-digital converters (which fold and amplify the input signal, emphasizing small signal variations) is feasible, but inherent non-ideal Tent Map gains reduce the output accuracy and restrict adoption within data acquisition systems. This paper demonstrates a novel compensation algorithm, developed as a digital electronic system, for non-ideal Tent Map gain, enabling high accuracy estimation of the analogue-to-digital converter analogue input signal. Approximation of the gain difference compensation values (reducing digital hardware requirements, enabling efficient real-time compensation), were also investigated via simulation. The algorithm improved the effective resolution of a 16, 20 and 24 Tent Map-stage analogue-to-digital converter model from an average of 5 to 15.5, 19.2, and 23 bits, respectively, over the Tent Map gain range of 1.9 to 1.99. The simulated digital compensation system for a seven Tent Map-stage analogue-to-digital converter enhanced the accuracy from 4 to 7 bits, confirming real-time compensation for non-ideal gain in Tent Map-based analogue-to-digital converters was achievable.

Highlights

The ability to detect small variations at high speeds in analogue signals is a key requirement for data acquisition (DAQ) systems when highly frequent, precise, and accurate measurements need to be made
When μ = 2 the effective resolution equaled the number of TM stages within the analogue-to-digital converters (ADCs) model
When the compensation algorithm was applied to the output of the 16, 20, and 24-stage ADC models there was a minimum increase in the effective resolution of 9, 13, and 17 bits, respectively

Summary

Introduction

The ability to detect small variations at high speeds in analogue signals is a key requirement for data acquisition (DAQ) systems when highly frequent, precise, and accurate measurements (with lower uncertainty) need to be made. DAQ systems typically require high resolution analogue-to-digital converters (ADCs) to detect small signal variations, higher resolutions and operational speeds generally increase the cost of the DAQ system [1,2]. Many photovoltaic (PV) systems necessitate analogue signals from sensors to be sampled and converted to the digital domain to enhance the reliability of energy delivery. One such example is their employment in battery energy storage systems (BESSs) [3]. Being capable of detecting smaller variations in the cell voltage could aid more precise battery management, improve SoC predictions, and increase battery lifespan

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