Charging Circuit Reverse Current Prevention via Dummy Cell
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional energy harvesting systems face challenges in preventing reverse currents due to differences in voltage between energy harvesting elements and power storage elements, especially under low environmental energy conditions, leading to inefficiencies and potential losses.
Innovation Solution
A charging circuit design that includes a first energy harvesting element and a second energy harvesting element of the same material, with a switch controlled based on the output voltage of the second element to prevent reverse currents, ensuring the switch is turned off when the output voltage falls below a threshold, thus mirroring the power generation state and reducing the need for high-precision comparison circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a comparison circuit is used to periodically compare voltages to control the switch, then reverse current prevention is attempted, but the switch may remain on between comparison timings causing reverse current, and the detection precision is insufficient for low generated currents
Solution Approach 1:
The patent introduces a dummy photovoltaic cell that replicates the electrical characteristics of the actual photovoltaic cell. This dummy cell generates a voltage that mirrors the power generation state of the real cell, allowing the switch control to accurately reflect real-time generation conditions without requiring high-precision voltage comparison circuits. The copying approach simplifies the control mechanism while maintaining reliability.
Solution Approach 2:
The dummy photovoltaic cell acts as an intermediary between the actual photovoltaic cell and the switch control circuit. Instead of directly comparing voltages with potential precision issues, the system uses the dummy cell's voltage as an intermediate signal that reliably indicates the power generation state, thereby preventing reverse current without complex comparison circuits.
2Productivity
If the switch on-resistance is reduced to improve energy transfer efficiency, then the potential difference for reverse current detection becomes very small, making it difficult to detect reverse current
Solution Approach 1:
By using a dummy photovoltaic cell to copy the electrical characteristics of the actual cell, the system obtains a voltage signal that accurately represents the power generation state. This approach allows for reliable reverse current prevention control without being constrained by the small potential differences that would exist across low-resistance switches, thus maintaining both efficiency and detection capability.
3Reliability
If conventional voltage comparison methods are used, then reverse current prevention is attempted, but the circuit complexity increases and cost increases due to high-precision comparison circuits
Solution Approach 1:
The dummy photovoltaic cell provides a simplified approach by generating a voltage that directly indicates the power generation state. This eliminates the need for complex voltage comparison circuits, reducing both circuit complexity and cost while maintaining reliable reverse current prevention. The solution trades the complexity of precision measurement for the simplicity of characteristic replication.
Solution Approach 2:
The dummy photovoltaic cell essentially serves itself and the main system by providing a control signal that automatically reflects the power generation state. This self-service mechanism eliminates the need for external high-precision comparison circuits, simplifying the overall system while ensuring reliable operation.
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 solution effectively prevents reverse currents and reduces energy losses by accurately reflecting the power generation state in real-time, allowing for efficient energy transfer and minimizing circuit complexity and cost.
Implementation Method 1
a first energy harvesting element that performs energy harvesting and supplies a current to a power storage element; a second energy harvesting element that performs energy harvesting
Data Source
AI summary
A charging circuit includes a first energy harvesting element that performs energy harvesting and supplies a current to a power storage element, a second energy harvesting element that performs energy harvesting, the second energy harvesting element is made in materials same as the first energy harvesting element, and a first switch that is disposed in a current path between the first energy harvesting element and the power storage element and that is put into an off-state, in a case where a first output voltage of the second energy harvesting element is smaller than a first value, thereby cutting off the current path.