캔틸레버형 압전 에너지 하비스터를 이용한 교량 무선 계측 센서의 전원 공급

Abstract

요 지

교량의 무선 계측 센서노드는 구조물의 안전진단 및 유지관리를 위해 활용되는 필수계측장비이다. 교량의 가로등, 전광판과는 달리 무선 계측 센서 노드는 상대적으로 저전력이 요구되므로 기존의 화학적인 배터리를 통한 전원 공급 방식이 아닌 차량의 이동, 풍하중 및 지진하중 등과 같은 주변 에너지원과의 높은 접목 가능성으로 지속적인 관심을 받아 왔다. 특히 진동에너지를 전기에너지로 변환시키는 압전체를 활용하여 무선 계측 센서노드를 구동시키는 연구는 지속적으로 시도되고 있다. 본 논문은 차량하중, 풍하중과 같은 주변 에너지원으로 교량이 가진될 때 발생되는 진동에너지를 전기에너지로 변환시킨 후 수집된 에너지를 이용하여 무선 계측 센서의 구동 가능성을 목적으로 하였다. 먼저 차량하중과 풍하중을 받는 영종대교와 서해대교의 케이블 행어 및 데크에서 수집된 가속도값으로 FFT분석을 하였다. FFT 분석결과로부터 지배 공진주파수 대역을 확인하였으며 압전 에너지 하비스터와의 공진여부를 검증을 하였다. 그 후 교량의 가속도값을 입력데이터로 하여 압전 에너지 하비스터를 가진한 다음 수집된 전력을 도출하였다. 연구를 통해 교량에 적용되는 압전 에너지 하비스터의 발생전력을 확인할 수 있었으며 가속도계, 변위계, 변형율계, 온도계 등의 무선 계측 센서 노드의 소요전력과 비교하여 무선 계측 센서의 구동 가능성을 확인하였다.

핵 심 용 어 : 압전세라믹, FFT, 공진주파수, 무선 계측 센서, 에너지 하비스팅 |Abstract

The wireless sensor node in bridge is essential equipment for safety diagnosis and maintenance. Because wireless sensor node requires low power relatively, it has received consistent intensive attention in terms of energy-supply possibility by environmental energy such as vehicle loads, wind loads and earthquake loads distinct from energy-supply by existent chemical battery apart from roadlamp and sign post in bridge. In particular the studies which transfers the vibration energy to electronic energy and operates wireless sensor node with piezoelectric have been tried consistently. This study is aimed at investigating the operation possibility of wireless sensor node using obtained electronic energy which is transferred by vibration energy from vehicle loads and wind loads when the bridge is behaviored. First, We conducted FFT analysis using acceleration data which is obtained by the cable, hanger and deck in Youngjong grand bridge and Sohae grand bridge controlled by vehicle loads and wind loads. Consequently, We identified governing resonance frequency bands in bridges and verified whether they have governing resonance frequency bands corresponding to those of piezoelectric harvester then deducted obtained energy after vibrating piezoelectric harvester. From the study, we identified the energy from piezoelectric energy harvester using vibration from cable and deck in bridge and found out the operation possibility of wireless sensor such as accelerometer node, displacement node, strain node and thermocouple node from the energy comparison with minimum required energy.

Keyword : Piezoelectric, FFT, Resonance frequency, Wireless sensor, Energy harvesting; Abstract

The wireless sensor node in bridge is essential equipment for safety diagnosis and maintenance. Because wireless sensor node requires low power relatively, it has received consistent intensive attention in terms of energy-supply possibility by environmental energy such as vehicle loads, wind loads and earthquake loads distinct from energy-supply by existent chemical battery apart from roadlamp and sign post in bridge. In particular the studies which transfers the vibration energy to electronic energy and operates wireless sensor node with piezoelectric have been tried consistently. This study is aimed at investigating the operation possibility of wireless sensor node using obtained electronic energy which is transferred by vibration energy from vehicle loads and wind loads when the bridge is behaviored. First, We conducted FFT analysis using acceleration data which is obtained by the cable, hanger and deck in Youngjong grand bridge and Sohae grand bridge controlled by vehicle loads and wind loads. Consequently, We identified governing resonance frequency bands in bridges and verified whether they have governing resonance frequency bands corresponding to those of piezoelectric harvester then deducted obtained energy after vibrating piezoelectric harvester. From the study, we identified the energy from piezoelectric energy harvester using vibration from cable and deck in bridge and found out the operation possibility of wireless sensor such as accelerometer node, displacement node, strain node and thermocouple node from the energy comparison with minimum required energy.

Keyword : Piezoelectric, FFT, Resonance frequency, Wireless sensor, Energy harvesting