Shared-Inductor Power Management for Multi-Source Energy Harvesting
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Solution Overview
Problem
The variability in electrical characteristics and energy outputs from different energy harvesting sources, such as photovoltaic cells, thermoelectric generators, and piezoelectric transducers, poses challenges for power management units (PMUs) in efficiently harvesting and storing energy.
Innovation Solution
A power management apparatus with a controller that operates a switching circuit to time-multiplex energy transfer between multiple energy harvesting input channels and an inductor, determining optimal operating parameters to maximize energy transfer and share inductor usage, adjusting parameters based on changes in inductor utilization and power output from each channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a PMU connects to multiple energy harvesting transducers to increase harvested energy, then the quantity of harvested energy increases, but the device complexity increases due to wide range of electrical characteristics
Solution Approach 1:
The patent combines multiple energy harvesting transducers with different electrical characteristics (PV cells, TEGs, piezoelectric transducers) into a single PMU system that shares common power management components including the inductor, switching circuit, and controller, thereby reducing overall device complexity while maintaining the ability to harvest from multiple sources
Solution Approach 2:
The PMU is designed with universal power management circuitry that can handle multiple types of energy harvesting transducers through a common inductor and switching architecture, allowing the same hardware to manage diverse electrical characteristics without requiring separate dedicated circuits for each transducer type
2Device complexity
If the PMU uses a single inductor for multiple energy harvesting input channels, then the device complexity is reduced, but the productivity decreases due to time-multiplexed energy transfer
Solution Approach 1:
The patent implements periodic action through time-multiplexed energy transfer cycles, where the single inductor is sequentially allocated to different energy harvesting input channels in repeating cycles. The controller systematically switches between channels, allowing each to transfer energy during its allocated time slots, thereby enabling a single inductor to serve multiple channels without permanent loss of functionality
Solution Approach 2:
The system employs dynamic allocation of the inductor to different input channels based on real-time energy harvesting conditions. The controller dynamically adjusts which channel receives inductor service in each time slot, optimizing the use of the shared resource while maintaining the ability to serve all channels over time
3Productivity
If the controller adjusts operating parameters to share inductor usage between multiple channels, then the inductor utilization is optimized, but the measurement precision required increases to determine optimal parameters
Solution Approach 1:
The controller implements feedback mechanisms to monitor energy transfer effectiveness from each input channel through the shared inductor. By measuring parameters such as voltage, current, and power transfer efficiency during time-multiplexed operation, the controller gathers data on actual inductor utilization and adjusts operating parameters accordingly to optimize performance while managing the complexity of precise measurements
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 approach enables efficient energy harvesting from multiple sources by maximizing overall energy/power transfer and optimizing inductor utilization, ensuring that energy is effectively stored and used to power loads.
Implementation Method 1
an inductor connection for connecting to an inductor; a switching circuit which is configured to selectively connect to the energy harvesting input channels, the inductor connection and the first energy storage element connection; and a controller which is configured to: operate the switching circuit to transfer energy between the energy harvesting input channels and the first energy storage element connection by a sequence of energy transfer cycles
Data Source
AI summary
A power management apparatus 20 comprises: a plurality of energy harvesting input channels 21-24; a first energy storage element connection for connecting to an energy storage element 32; an inductor connection 27; and a switching circuit 28. A controller 30 operates the switching circuit to transfer energy between the energy harvesting input channels 21-24 and the first energy storage element connection 25 by a sequence of energy transfer cycles. Each energy harvesting input channel 21-24 is allocated a plurality of the energy transfer cycles. The controller 30 determines operating parameters for operating the switching circuit 28 which transfer a maximum power from the electrical energy harvesting source connected to the energy harvesting input channel and a maximum power inductor utilisation factor. The controller 30 determines a set of adjusted operating parameters for sharing use of the inductor between the plurality of energy harvesting input channels 21-24. An energy harvesting input channel 21-24 is selected for adjustment based on an effect of a change in the inductor utilisation factor and a corresponding change in power of the energy harvesting input channel.