Segmented MPPT Boost Converter for PV Array Power Optimization
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Solution Overview
Problem
Large photovoltaic (PV) arrays with non-identical cells or uneven insolation and temperature conditions experience sub-optimal output power due to the inability of existing maximum power point tracking (MPPT) systems to handle multiple local maxima in power curves, leading to inefficient energy harvesting.
Innovation Solution
A MPPT device with a switched mode topology, including a boost converter and a differential Schmitt-trigger, that adapts the electrical operating point of PV arrays to maximize output power by controlling the transfer ratio and using hysteretic control to stabilize the PV voltage and ripple voltage, allowing for local maximum power point tracking of each panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single MPPT is used for the entire PV array, then device complexity is reduced, but the ability to handle multiple local maxima and optimize individual panel performance deteriorates
Solution Approach 1:
The patent divides the PV array into multiple independent panels, each equipped with its own local MPPT device. This segmentation allows each panel to independently track its maximum power point, effectively handling multiple local maxima in the overall power curve while maximizing energy harvesting from each individual panel under varying insolation and temperature conditions.
2Ease of operation
If panels are connected in parallel to equalize voltage, then ease of operation is improved, but the ability of non-identical panels to work at their individual MPP deteriorates
Solution Approach 1:
Each parallel-connected panel is equipped with its own local MPPT device, creating independent control segments. This allows each panel to operate at its individual maximum power point despite voltage equalization requirements in parallel connections, as each MPPT independently adjusts its panel's operating point while maintaining the parallel voltage constraint.
3Ease of operation
If panels are connected in series to equalize current, then ease of operation is improved, but the ability of non-identical panels to work at their individual MPP deteriorates
Solution Approach 1:
Each series-connected panel is equipped with its own local MPPT device, creating independent control segments within the series string. This allows each panel to operate at its individual maximum power point despite current equalization requirements in series connections, as each MPPT independently adjusts its panel's operating point while maintaining the series current constraint.
4Productivity
If local MPPT is implemented for each panel, then energy harvesting efficiency is improved, but device complexity and cost increase
Solution Approach 1:
The patent implements local MPPT devices at the panel level, segmenting the control function across multiple independent units. While this increases the number of components, each device operates independently with simplified control logic, allowing parallel implementation that scales linearly with array size while maximizing energy harvesting from each panel.
Solution Approach 2:
The local MPPT devices are designed as universal, identical units that can be applied to any panel in the array regardless of its specific operating conditions. This multi-functionality allows the same standardized device to handle diverse scenarios (different insolation, temperature, panel characteristics) uniformly, simplifying design and deployment.
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 enables the PV array to operate at its optimal power point, even under varying conditions, by stabilizing the PV voltage and ripple voltage, and allows for efficient energy harvesting by summing the output power from individual MPPTs connected in series or parallel.
Implementation Method 1
a switched mode topology, where the switched mode topology includes a boost topology that establishes a variable transfer ratio between a variable input voltage and a variable output voltage of the converter
Implementation Method 2
A MPPT device with a switched mode topology, including a boost converter and a differential Schmitt-trigger, that adapts the electrical operating point of PV arrays to maximize output power by controlling the transfer ratio and using hysteretic control to stabilize the PV voltage and ripple voltage
Data Source
AI summary
A maximum power point tracking (MPPT) device is provided that includes a converter, having a switched mode topology, where the switched mode topology includes a boost topology that establishes a variable transfer ratio between a variable input voltage and a variable output voltage of the converter, where the switched mode topology changes according to a power load on a power generator. The MPPT device further includes a control section, where the control section maximizes an output power of the power generator by controlling the variable transfer ratio, where the MPPT device optimizes an electrical operating point of the power generator.