Thermoelectric Generator Starting Circuit for Low Voltage Conversion
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Solution Overview
Problem
Thermoelectric generators produce low electrical output voltage, especially with small temperature differences, and existing DC to DC voltage converters are inefficient at handling ultra-low input voltages, limiting their effectiveness in converting heat flux into usable energy.
Innovation Solution
A thermoelectric generator system incorporating a starting circuit and a DC to DC converter with a controller that dynamically switches between ultra-low and low voltage operation modes, utilizing a transformer and metal oxide semiconductor depletion transistors to efficiently convert ultra-low input voltages into a usable range of 1 to 5 volts, allowing for self-oscillation at very low input levels and optimizing voltage conversion efficiency across varying input ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a thermoelectric element is used to generate electricity from heat flux, then electrical energy is produced, but the output voltage remains rather low (typically 1 to 10 mV for small temperature differences)
Solution Approach 1:
The patent introduces a DC to DC voltage converter as an intermediary device between the thermoelectric element and the load. This converter acts as a mediator that transforms the ultra-low voltage output (1-10 mV) from the thermoelectric element into a usable voltage range (1-5 V), enabling the system to effectively utilize small temperature differences while achieving practical output voltages
Solution Approach 2:
The system changes the voltage parameter through the DC to DC converter, which dynamically adjusts the output voltage based on the input voltage from the thermoelectric element. The converter modifies the electrical parameters to maintain efficient operation across varying temperature differences, transforming the relationship between temperature input and voltage output
2Power
If a DC to DC voltage converter is added to increase the output voltage, then the voltage reaches usable levels (1 to 5 V), but the converter cannot work efficiently with ultra-low voltage inputs (a few milliVolts)
Solution Approach 1:
The patent employs a dynamic control system that continuously monitors the input voltage from the thermoelectric element and adjusts the converter's operation accordingly. The controller dynamically modifies the converter's working parameters to maintain optimal efficiency across the entire operating range, adapting to changing temperature differences and input voltage levels in real-time
Solution Approach 2:
The system segments the operating range into different modes: an ultra-low voltage mode for very small temperature differences and a standard mode for larger temperature differences. The controller automatically switches between these segmented operating modes to ensure efficient conversion across all conditions, preventing energy loss that would occur if a single fixed-mode converter were used
3Adaptability or versatility
If the temperature difference is kept small (1 to 10 °C), then the application becomes more versatile and less invasive, but the electrical output voltage becomes rather low
Solution Approach 1:
The DC to DC voltage converter serves as an intermediary that enables the system to operate with small temperature differences (1-10 °C) while still producing usable output voltages. This mediator allows the system to be less invasive and more versatile in applications where large temperature differences are not feasible, while compensating for the low input voltage through active conversion
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 efficient voltage conversion and power generation even at small temperature differences, reducing manufacturing costs and enabling self-powered applications with minimal PN type elements, while preventing system oscillation at critical power levels, thereby enhancing the overall energy harvesting capability.
Implementation Method 1
A thermoelectric generator (TEG), also called Seebeck generator, is a device that converts heat flux directly into electrical energy through a phenomenon called the Seebeck effect
Implementation Method 2
the starting circuit comprises a transformer, a third switch and a rectifier
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a thermoelectric generator comprising: - a voltage source (40) comprising a thermoelectric element (42), - a starting circuit (20) connected to the voltage source (40), - a DC to DC converter circuit (30) connected to the voltage source (40), - an output (50) connected to the starting circuit (20) and connected to the DC to DC converter circuit (30), and - a controller (60) having an input connected to the voltage source (40), and outputs connected to the starting circuit (20) and to the DC to DC converter circuit (30), wherein the controller (60) is configured: - to deactivate the starting circuit (20) and to activate the DC to DC converter circuit (30) when a voltage (u6) at the output (50) or when a voltage provided by the voltage source (40) rises above a predefined upper voltage threshold, and - to reactivate the starting circuit (20) and to deactivate the DC to DC converter circuit (30) when a voltage (u6) at the output (50) or when a voltage provided by the voltage source (40) drops below a predefined lower voltage threshold.