Electroactive Polymer Generator Circuit for Energy Harvesting
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Solution Overview
Problem
Existing generator circuits designed for piezoelectric materials are inefficient for compliant electroactive polymers due to their different electrical and mechanical properties, particularly higher electrical resistance and greater deflection, which affects the harvesting of electrical energy from mechanical inputs.
Innovation Solution
A generator circuit with a capacitor that collects electrical energy from an electroactive polymer transducer by leveraging the varying capacitance caused by mechanical deflection, using a mechanism that applies a small bias voltage and transfers mechanical energy to the transducer to increase capacitance, allowing for efficient energy harvesting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If piezoelectric materials are used, then electrical resistance is low, but deflection is limited
Solution Approach 1:
The patent changes the material parameter from rigid piezoelectric materials to compliant electroactive polymers, which have different electrical and mechanical properties. This allows the material to achieve much larger deflections while the circuit is designed to accommodate the resulting higher electrical resistance and variable capacitance characteristics
Solution Approach 2:
The patent employs a dynamic circuit configuration that adapts to the varying capacitance of the compliant polymer during deflection. The circuit includes switching elements and energy storage components that dynamically adjust to capture energy efficiently throughout the polymer's deflection cycle, rather than using a static circuit design
2Adaptability or versatility
If compliant electrodes are used, then compliance is improved, but electrical resistance increases
Solution Approach 1:
The patent uses composite electrode structures that combine compliant materials (such as carbon greases or conductive polymers) with conductive fillers or networks. This creates a composite that maintains both compliance for large deflections and sufficient electrical conductivity for efficient energy harvesting
Solution Approach 2:
The patent modifies the electrical parameters of the compliant electrode materials by incorporating conductive additives or changing the material composition to achieve an optimal balance between compliance and electrical resistance, allowing both characteristics to coexist
3Productivity
If generator circuits for piezoelectric materials are used, then circuit design is simple, but energy harvesting efficiency is low
Solution Approach 1:
The patent divides the energy harvesting circuit into functional modules including rectification stages, energy storage capacitors, and switching elements. Each module handles a specific aspect of the energy conversion process, making the overall complex circuit manageable and allowing optimization of each segment for the compliant polymer's characteristics
Solution Approach 2:
The patent introduces intermediate energy storage capacitors and buffering stages that mediate between the variable capacitance of the compliant polymer and the load. These intermediaries smooth out the variable electrical characteristics and enable efficient energy transfer despite the complex source impedance
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables efficient conversion of mechanical energy into electrical energy, overcoming the inefficiencies of traditional circuits by utilizing the compliant electroactive polymer's deflection to increase capacitance and generate electrical energy effectively.
Implementation Method 1
The transducer has a capacitance that varies with deflection of the electroactive polymer
Implementation Method 2
an electroactive polymer transducer to harvest electrical energy from the electroactive polymer
Data Source
AI summary
Described herein is a generator with an electroactive polymer transducer. The transducer has a capacitance that varies with deflection of a polymer included in the transducer. The generator also includes a generator circuit, coupled to the electroactive polymer transducer, that includes a capacitor. The generator circuit is configured such that the capacitor collects electrical energy from the electroactive polymer transducer in response to a change in capacitance of the polymer.