Self-Optimizing Energy Harvester with Dynamic Set Point Control
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Solution Overview
Problem
Conventional DC-DC converters are inefficient over a wide range of input voltages and source impedance variations, particularly in thermoelectric generators, leading to reduced power transfer and requiring customization for each generator's source voltage, which is costly and bulky.
Innovation Solution
A self-optimizing energy harvester system with a feedforward circuit dynamically adjusts the boost circuit's operating point using a dynamic set point resistance, formed by a variable and reference resistance, to match the source impedance and voltage, ensuring high output power efficiency across a wide range of input voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a fixed DC-DC converter is designed for a specific input voltage, then high output power efficiency (80-95%) is achieved, but the converter can only operate efficiently over a narrow voltage range and requires customization for each generator's source voltage
Solution Approach 1:
The patent implements a dynamic set point control mechanism that continuously adjusts the DC-DC converter's operating parameters based on the generator's instantaneous source voltage and impedance. This dynamic adaptation allows the converter to maintain high efficiency (80-95%) across a wide voltage range (at least 9:1 ratio) without requiring physical customization, resolving the contradiction between fixed高效率 design and voltage range adaptability
Solution Approach 2:
The system changes key operating parameters (set point voltage, switching frequency, duty cycle) in real-time based on the generator's output characteristics. By dynamically adjusting these parameters rather than fixing them, the converter adapts to varying source voltages and impedances while maintaining optimal efficiency, thus solving the contradiction between fixed parameter design and variable input conditions
2Reliability
If storage elements (capacitors and batteries) are added to handle environmental variability, then power supply reliability is improved, but the system becomes bulky, expensive, and requires periodic maintenance
Solution Approach 1:
The patent implements a self-optimizing control system that automatically monitors generator output and adjusts converter parameters without external intervention or additional storage elements. The system serves itself by dynamically matching impedance and adjusting operating points, eliminating the need for bulky capacitors and batteries while maintaining reliable power supply through intelligent control rather than physical energy buffering
Solution Approach 2:
The system employs feedback control mechanisms that continuously monitor the generator's source voltage and impedance, then adjust the DC-DC converter's operation accordingly. This closed-loop feedback enables the system to adapt to environmental variability and maintain stable power output without requiring large storage elements, thus improving reliability while reducing system bulk and maintenance needs
3Power
If the converter input impedance is changed to match the source impedance for maximum power transfer, then power transfer efficiency is improved, but the converter becomes limited to specific generator types and requires customization
Solution Approach 1:
The patent implements dynamic impedance matching that continuously adjusts the converter's input impedance to match the generator's source impedance in real-time. This dynamic approach allows the system to achieve maximum power transfer across multiple generator types with different impedance characteristics without requiring physical customization, resolving the contradiction between optimized power transfer and generator compatibility
Solution Approach 2:
The system achieves universal compatibility with different generator types (thermoelectric, photovoltaic, piezoelectric) through a single adaptable DC-DC converter design. The universal interface dynamically adjusts its input impedance and operating parameters to match any generator's characteristics, enabling one converter to serve multiple generator types while maintaining optimal power transfer efficiency
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 system achieves high output power efficiency (at least 9:1 range of source voltage) by dynamically optimizing the boost circuit, reducing the need for storage elements and maintaining efficiency even when input voltage varies, thus enhancing the reliability and compactness of energy harvesting systems.
Implementation Method 1
A thermoelectric generator may be coupled to a temperature difference for providing heat flow through the thermoelectric generator. The thermoelectric generator may produce a source voltage
Data Source
AI summary
A self-optimizing energy harvester comprises a thermoelectric generator coupling to a thermal source, producing a source voltage greater than a minimum start-up voltage, where the thermoelectric generator drives a boost circuit and a feedforward circuit, delivering power to a load. A conventional boost circuit has a maximum output power only at the input voltage for which a fixed set point resistor is chosen. The feedforward circuit dynamically optimizes the boost circuit according to a dynamic set point resistance, thus increasing output power for a wide range of input voltages, relative to using a fixed reference resistor. The dynamic set point resistance is the sum of a variable resistance and a reference resistance. A sample element forms a differential voltage between the source and input voltage elements, and the variable resistance corresponds to the differential voltage. A reference resistor is chosen to establish the minimum start-up voltage.