Solar Cell MPPT Control via Bidirectional Voltage Sweep
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Solution Overview
Problem
Existing Maximum Power Point Tracking (MPPT) methods for solar cells face challenges in accurately identifying the real maximum power point due to errors in power detection, particularly when the slope of the voltage-current curve is smooth, leading to suboptimal power output.
Innovation Solution
A control method and apparatus that adjust the duty ratio of a switching unit in a solar cell's conversion module to gradually decrease the output voltage from the open-circuit voltage, then reverse the adjustment when the voltage reaches a preset value below the maximum power point, allowing for precise tracking of the maximum power by comparing current and previous output powers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the output voltage is gradually decreased from open-circuit voltage by controlling duty ratio to track maximum power point, then the power output increases, but the tracking precision deteriorates due to smooth curve slope and detection errors
Solution Approach 1:
The patent applies inversion by reversing the traditional voltage adjustment direction. Instead of continuously decreasing voltage from open-circuit voltage, the method first decreases voltage to a preset value below the maximum power point voltage, then reverses direction to increase voltage until power decreases, thereby locating the true maximum power point through bidirectional search
Solution Approach 2:
The patent implements feedback by continuously monitoring output power and comparing it with previous power values. When the current power is less than previous power during voltage increase, the system determines the maximum power point has been passed and adjusts accordingly, creating a closed-loop control mechanism
2Ease of operation
If the duty ratio is continuously increased to decrease output voltage from open-circuit voltage, then the tracking process is simple, but the computed maximum power point is less than the real maximum power point
Solution Approach 1:
The patent applies inversion by reversing the traditional voltage adjustment direction. Instead of continuously decreasing voltage from open-circuit voltage, the method first decreases voltage to a preset value below the maximum power point voltage, then reverses direction to increase voltage until power decreases, thereby locating the true maximum power point through bidirectional search
Solution Approach 2:
The patent implements periodic action through two distinct phases: a first change direction phase where voltage decreases from open-circuit voltage to preset value, and a second change direction phase where voltage increases from preset value. This periodic bidirectional adjustment ensures accurate tracking while maintaining operational simplicity
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 more accurate and efficient tracking of the solar cell's maximum power point, ensuring that the output voltage and current remain within preset ranges, thereby maximizing power generation and improving tracking precision.
Implementation Method 1
an output voltage of the solar cell is converted to a voltage required by a load via a conversion module including a switching unit
Data Source
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Figure 5~6
AI summary
Disclosed are a method and device for tracking control of a maximum power point of a solar cell, wherein an output voltage of the solar cell is converted to a voltage required by a load via a conversion module comprising a switching unit. The control method comprises: acquiring an open-circuit voltage of the solar cell (S1); adjusting a duty cycle of the switching unit such that an output voltage of the solar cell decreases from the open-circuit voltage gradually in a first change direction (S2); if the output voltage of the solar cell is less than or equal to a predetermined voltage value, reversely adjusting the duty cycle of the switching unit, wherein the predetermined voltage value is less than the output voltage of the solar cell corresponding to the maximum power of the solar cell (S3); calculating a current output power of the solar cell; and if the current output power is less than a previous output power, determining that the previous output power is the maximum output power of the solar cell (S5). The control method can track the actual maximum power value more easily.