Multi-Threshold Charging Circuit for Energy Harvesting
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Solution Overview
Problem
Existing charging devices face inefficiencies in rapidly charging electronic devices while minimizing power wastage, especially when power generation is fluctuating or low, leading to frequent battery switching and increased consumption.
Innovation Solution
A charging device with multiple thresholds for battery level detection, allowing dynamic switching between charge and discharge batteries based on their states, optimizing power usage and preventing wastage by adjusting switching criteria based on battery levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single threshold is used for battery switching, then the control logic is simple, but frequent switching occurs when battery levels are close to the threshold, increasing power consumption and causing power wastage
Solution Approach 1:
The single threshold is segmented into multiple thresholds (first threshold and second threshold) to create distinct switching zones. The first threshold triggers switching when the charge-side battery level reaches it, while the second threshold (lower than the first) prevents immediate reverse switching, creating a hysteresis effect that reduces frequent switching and associated power wastage.
Solution Approach 2:
The switching thresholds are made dynamic rather than static by introducing asymmetric thresholds for charging and discharging states. The system adapts the threshold values based on the operational state, using a higher threshold for charge-to-discharge switching and a lower threshold for discharge-to-charge switching, thereby optimizing power management under varying conditions.
2Productivity
If power generated by energy harvesting is directly supplied to the external device when battery levels are low, then the device can be charged, but the charging speed is limited by the low power generation rate
Solution Approach 1:
The charge-side secondary battery is charged in advance using energy harvesting power when available, storing energy before it is needed. This preliminary charging action allows the system to discharge at higher rates when the external device requires power, thereby increasing charging speed without wasting the harvested energy.
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 enables swift charging of electronic devices while reducing power wastage by intelligent battery management, ensuring efficient use of fluctuating power sources and prolonging battery health.
Implementation Method 1
Power generation by converting nonelectrical energy in the environment into electrical energy, such as solar power generation, is also referred to as energy harvesting
Data Source
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AI summary
A charging device comprises: a plurality of secondary batteries 11; and a charge and discharge control circuit 13 that controls, from among the plurality of secondary batteries 11, a secondary battery 11 as a charge-side secondary battery 11 charged with power generated by energy harvesting, and an other secondary battery 11 as a discharge-side secondary battery 11 discharged to supply stored power to a device 3, wherein at least either of: a plurality of thresholds each as a charge amount detection threshold; and a plurality of thresholds each as a discharge amount detection threshold are set, and each time the remaining battery level of the charge-side secondary battery 11 reaches the charge amount detection threshold and each time the remaining battery level of the discharge-side secondary battery 11 reaches the discharge amount detection threshold, the charge and discharge control circuit 13 determines whether or not to perform switching between the secondary batteries 11 subjected to charging and discharging, depending on the remaining battery level of the charge-side secondary battery 11 and the remaining battery level of the discharge-side secondary battery 11.