MPPT Mode Switching for PV Array Mismatch
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Solution Overview
Problem
In energy generating systems, particularly photovoltaic arrays, maximum power point tracking (MPPT) techniques fail to provide accurate results under mismatched or partially shaded conditions, leading to reduced power production due to local maxima selection by DC-DC converters and increased electrical losses.
Innovation Solution
A method and system that selectively switch between centralized and distributed MPPT modes based on the operating conditions of energy generating devices, using a central array controller to determine quasi-ideal conditions and adjust local converters to operate each panel at its maximum power point, minimizing losses and optimizing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If centralized MPPT is used under ideal conditions, then system complexity is reduced and efficiency is improved, but under mismatched or shaded conditions the power production accuracy deteriorates
Solution Approach 1:
The system dynamically switches between centralized and distributed MPPT modes based on operating conditions. A controller monitors environmental parameters and automatically selects the appropriate MPPT strategy, making the system adaptive rather than static. This resolves the contradiction by allowing the system to use simple centralized control when ideal and complex distributed control when needed.
Solution Approach 2:
The invention changes the operational parameters of the MPPT system based on detected conditions. When mismatched or shaded conditions are detected, the system transitions from centralized to distributed MPPT mode, effectively changing the control parameter structure to match the environmental conditions and maintain optimal power production accuracy.
2Productivity
If distributed MPPT with multiple DC-DC converters is used for each panel, then power production accuracy is improved under mismatched conditions, but electrical losses increase and system complexity increases
Solution Approach 1:
The system uses dynamic mode switching to activate distributed MPPT with multiple converters only when mismatched or shaded conditions are detected. Under ideal conditions, the system uses centralized MPPT with fewer converters active, reducing electrical losses. This dynamic adaptation resolves the contradiction between accuracy and energy losses.
Solution Approach 2:
The invention segments the MPPT control into different modes: centralized control for ideal conditions and distributed control for mismatched conditions. This segmentation allows the system to apply the appropriate level of complexity and converter usage based on actual needs, minimizing unnecessary electrical losses while maintaining accuracy when required.
3Productivity
If distributed MPPT with multiple DC-DC converters is used, then each panel can operate at its maximum power point under mismatched conditions, but the number of converters increases system complexity and cost
Solution Approach 1:
The system dynamically adjusts the number of active converters based on operating conditions. Under ideal conditions, fewer converters are used in centralized mode. Under mismatched or shaded conditions, the system activates additional converters in distributed mode to achieve accurate per-panel MPPT. This dynamic configuration resolves the contradiction between accuracy and device complexity.
Solution Approach 2:
The invention changes the system configuration parameter (number of active converters) based on environmental conditions. The controller monitors conditions and adjusts the converter activation state, transitioning from a low-complexity centralized configuration to a high-complexity distributed configuration only when necessary for maintaining power production accuracy.
Data Source
AI summary
A method for selecting between centralized and distributed maximum power point tracking in an energy generating system is provided. The energy generating system includes a plurality of energy generating devices, each of which is coupled to a corresponding local converter that includes a local controller. The method includes determining whether there is at least a threshold amount of mismatch between operating characteristics of the energy generating devices. The energy generating system is placed in a centralized maximum power point tracking (CMPPT) mode when there is not at least the threshold amount of mismatch and is placed in a distributed maximum power point tracking (DMPPT) mode when there is at least the threshold amount of mismatch.