Flipping-Capacitor Rectifier Circuit for Piezoelectric Energy Harvesting
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Solution Overview
Problem
Conventional piezoelectric energy harvesting systems face limitations in power extraction efficiency due to charge loss in parasitic capacitors and require bulky high-Q inductors, which increase system size and cost, especially at high excitation frequencies.
Innovation Solution
A flipping-capacitor rectifier circuit with a reconfigurable capacitor array and active rectifier that forms multiple reconfiguration phases to flip the voltage across the piezoelectric energy harvester, eliminating the need for external inductors and enhancing power extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional piezoelectric energy harvesting systems use parasitic capacitors for power extraction, then power extraction efficiency is limited, but system simplicity is maintained
Solution Approach 1:
The parasitic capacitor is segmented into multiple reconfigurable capacitor units that can be independently controlled through switching networks, enabling phase-specific charge extraction while maintaining overall system functionality
Solution Approach 2:
The capacitor configuration dynamically reconfigures between different phases (first phase, second phase, third phase) through controlled switching, allowing the system to adapt charge extraction strategies to maximize power harvest at different moments in the excitation cycle
2Loss of energy
If bulky high-Q inductors are used to enhance power extraction, then power extraction efficiency improves, but system size and cost increase
Solution Approach 1:
The inductor component is completely extracted from the system by replacing the conventional inductor-based power extraction mechanism with a capacitor-based reconfiguration approach, eliminating the need for bulky high-Q inductors while maintaining power extraction functionality
Solution Approach 2:
The electromagnetic inductor-based charge extraction mechanism is substituted with an electrostatic capacitor-based mechanism, using voltage flipping and charge redistribution through switching networks to achieve power extraction without magnetic components
3Power
If conventional rectifier circuits are used, then system simplicity is maintained, but output power enhancement is limited
Solution Approach 1:
The rectifier circuit employs periodic switching actions that synchronize with the excitation frequency, creating distinct operational phases (first reconfiguration phase, second reconfiguration phase, third reconfiguration phase) that systematically enhance power extraction through timed charge manipulation
Solution Approach 2:
The circuit dynamically changes voltage parameters across the piezoelectric element by flipping voltage polarity and magnitude through capacitor reconfiguration, transforming the voltage waveform to maximize power transfer to the load while maintaining circuit integration
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 enhances output power by up to 4.83 times at an excitation frequency of 110 kHz, achieving a fully integrated and efficient energy harvesting solution without the need for external components.
Implementation Method 1
enhances an output power of a piezoelectric energy harvester (PEH)
Implementation Method 2
The active rectifier connects with the flipping capacitor and rectifies an AC voltage of the PEH
Data Source
AI summary
A flipping-capacitor rectifier circuit that enhances an output power of a piezoelectric energy harvester (PEH). The flipping-capacitor rectifier circuit includes a flipping capacitor, a plurality of switches, and an active rectifier. The flipping capacitor is connected in parallel with the PEH and forms at least three reconfiguration phases by turning on one or more of the switches. The active rectifier connects with the flipping capacitor in parallel and rectifies an AC voltage of the PEH. The flipping capacitor flips a voltage across a capacitor of the PEH to enhance the output power of the PEH by extracting power from the capacitor of the PEH.