Electrostatic Energy Harvester Asynchronous Switching Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electrostatic energy harvesters face inefficiencies in converting mechanical vibrational energy into electrical energy, requiring multiple devices to power low-energy components due to high current leakage, complex control circuitry, and limited energy harvesting windows, with dual variable capacitors adding complexity and energy losses.
Innovation Solution
An electrostatic energy harvester design that utilizes a battery or capacitor for energy storage, dual variable capacitors connected through a high node and grounding switches, and a switching control module to alternate energy investments and harvesting, reducing energy losses by retaining remnant energy and simplifying control circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If synchronous electrical energy transfer stages are used, then electrical energy can be transferred efficiently, but high current leakage and complex control circuitry occur
Solution Approach 1:
The patent extracts and eliminates the synchronous control circuitry from the energy transfer stage, replacing it with an asynchronous operation mode that achieves energy transfer without the complex timing control and high current leakage associated with synchronous stages
Solution Approach 2:
Instead of using synchronous control to manage energy transfer, the patent inverts the approach by using asynchronous operation where energy transfer occurs naturally through the vibration cycle without active control, thereby eliminating the source of current leakage and control complexity
2Device complexity
If asynchronous electrical energy transfer stages are used, then control circuitry is simplified, but two batteries are required and energy harvesting window is limited
Solution Approach 1:
The patent merges the energy storage function into a single battery by implementing a circuit architecture where the single battery can serve both energy storage roles through strategic capacitor switching, eliminating the need for two separate batteries while maintaining asynchronous operation benefits
Solution Approach 2:
The single battery is designed to perform multiple functions by combining with the capacitor bank, where the battery serves as both the primary energy source and works in conjunction with capacitors to extend the energy harvesting window, providing universal energy supply for different operational phases
3Productivity
If dual variable capacitors are used to double energy harvested, then energy harvesting efficiency increases, but switching control module complexity and energy losses increase
Solution Approach 1:
The patent implements periodic switching of the dual variable capacitors synchronized with the vibration cycle, where capacitors are switched between charging and discharging phases at optimal points in the vibration period, enabling doubled energy harvest while using a simplified control module that only needs to track vibration phase rather than complex timing
Solution Approach 2:
The dual variable capacitors are designed to automatically charge and discharge based on the vibration-induced potential differences, with the system self-regulating the energy transfer between capacitors and the battery without requiring complex external control, thereby reducing control module complexity while maintaining high energy harvest
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
This design enables efficient electrical energy harvesting with reduced energy losses and complexity, allowing for twice the energy to be harvested per vibration cycle while minimizing the need for complex control circuitry and dual batteries.
Implementation Method 1
Electrostatic energy harvesters are used to convert mechanical vibrational energy into electrical energy
Implementation Method 2
the first variable capacitor is initially active. First, an initial electrical energy investment (i.e., a pre-charge) is provided from the electrical energy storage component to the high node (and hence to the first variable capacitor). External vibrations induce oscillations of the high node oscillating mass, resulting in capacitance of the first variable capacitor alternating between increasing and decreasing
Data Source
AI summary
An electrostatic energy harvester broadly comprises an electrical energy storage component, an electrical energy transfer stage, first and second variable capacitors, and a switching control module. The electrical energy transfer stage includes diode-connected transistors and dictates electrical energy transfer between the electrical energy storage component and the variable capacitors. The switching control module timely switches between the first and second variable capacitors according to a state machine. Subsequent electrical energy investments from the electrical energy storage component are less than an initial electrical energy investment due to remnant electrical energy remaining at the previously active one of the first and second variable capacitors from previous electrical energy harvesting.