Switched-Capacitor Converters for Per-Panel MPPT in PV Arrays
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Solution Overview
Problem
Existing photovoltaic (PV) systems face inefficiencies due to asymmetries caused by temperature variations, dirt, panel aging, and orientation, which are not effectively addressed by current architectures that rely on magnetic components and distributed power conversion methods.
Innovation Solution
The implementation of integrated switched-capacitor DC-DC converters within photovoltaic systems, allowing for per-panel maximum-power-point tracking and grid-tie inverter interfaces with decoupled MPPT and energy balance control loops, reduces manufacturing costs and enhances tracking efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If distributed power conversion with magnetic components is used for per-panel MPPT, then tracking efficiency is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The patent replaces magnetic components (inductors, transformers) with a capacitor-based switched-capacitor converter. This substitution eliminates the need for magnetic materials and complex magnetic component manufacturing, thereby reducing manufacturing cost and device complexity while maintaining the per-panel MPPT functionality. The capacitor-based approach uses simple electronic switching to achieve power conversion without magnetic fields.
Solution Approach 2:
The patent changes the fundamental operating parameters of the power conversion system by using voltage multiplication through switched-capacitor networks instead of magnetic induction. This parameter change allows achieving the same power conversion function with different physical principles, avoiding the complexities associated with magnetic components while preserving tracking efficiency.
2Volume of moving object
If high frequency switching is used to minimize magnetic component size, then component size is reduced, but manufacturing cost and electromagnetic interference increase
Solution Approach 1:
The patent substitutes magnetic component-based high frequency switching with a capacitor-based switched-capacitor converter that operates at lower frequencies. This substitution eliminates the need for miniaturized magnetic components and their associated manufacturing challenges, reducing both component size and manufacturing cost simultaneously by using simple capacitors and electronic switches.
3Loss of energy
If distributed converters operate at high switching frequencies, then power conversion efficiency is improved, but electromagnetic interference with FCC bands increases
Solution Approach 1:
The patent changes the switching frequency parameter from high frequency to lower frequency operation. The switched-capacitor converter achieves acceptable power conversion efficiency at lower frequencies, thereby avoiding the electromagnetic interference issues that plague high-frequency distributed converters while still maintaining reasonable efficiency levels.
4Productivity
If per-panel MPPT is implemented with existing architectures, then energy extraction is maximized, but system complexity and cost increase
Solution Approach 1:
The patent replaces complex magnetic component-based distributed converters with simple capacitor-based switched-capacitor converters. This substitution maintains per-panel MPPT capability for maximizing energy extraction while dramatically reducing system complexity through the use of simple capacitors, diodes, and transistors instead of complex magnetic components.
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 increases overall array tracking efficiency, reduces manufacturing costs, and stabilizes grid-tie inverter operations by relying on feedforward terms, while minimizing power losses and optimizing energy extraction.
Implementation Method 1
a switched-capacitor DC-DC converter deployed with the solar cell during or after manufacturing of the cell
Implementation Method 2
a solar cell; and a switched-capacitor DC-DC converter deployed with the solar cell
Data Source
AI summary
Described is a method and apparatus for per-panel photovoltaic energy extraction with integrated converters. Also described are switched-capacitor (SC) converters have been evaluated for many applications because of the possibility for on-chip integration; applications to solar arrays are no exception. Also described is a comprehensive system-level look at solar installations, finding possibilities for optimization at and between all levels of operation in an array. Specifically, novel concepts include new arrangements and options for applying switched-capacitor circuits at 3 levels: for the panel and sub-panel level, as part of the overall control strategy, and for ensuring stable and robust interface to the grid with the possibility of eliminating or reducing the use of electrolytic capacitors.