Distributed Inverter Segmentation for PV Reliability
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Solution Overview
Problem
Conventional microinverters for photovoltaic systems face challenges in reliability, efficiency, and cost due to their design, which is exacerbated by their placement in hostile outdoor environments, and they lack upgradeability and safety features, making installation, maintenance, and code compliance complex and expensive.
Innovation Solution
A distributed inverter system with microinverters placed in proximity to photovoltaic modules and a gateway located in a protected environment, where only necessary functions are collocated with microinverters, and system control and coordination are performed remotely, allowing for hardware, software, and firmware upgrades, enhancing safety, reliability, and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If microinverters are placed in proximity to PV modules, then AC power harvest is improved and string design challenges are removed, but reliability and efficiency deteriorate due to exposure to hostile outdoor environments
Solution Approach 1:
The inverter system is segmented into two distinct parts: microinverters placed at each PV module location for optimal power harvesting, and a remote gateway unit that provides protective functions. This segmentation allows the microinverters to be positioned where they can maximize AC power harvest while the gateway unit assumes the role of protecting against environmental hazards and grid issues.
Solution Approach 2:
A remote gateway unit is introduced as an intermediary between the microinverters and the utility grid. This gateway provides isolation and protection, shielding the microinverters from hostile outdoor conditions and grid disturbances. The gateway acts as a mediator that handles safety functions and grid coordination while the microinverters focus on power conversion.
2Productivity
If microinverters are placed in proximity to PV modules, then per-module MPPT is enabled, but device complexity and cost increase
Solution Approach 1:
The system segments MPPT functionality to the individual microinverter units at each PV module, enabling per-module maximum power point tracking. This segmentation allows each module to operate independently at its optimal operating point, maximizing overall system productivity while distributing complexity across multiple simple units rather than one complex centralized inverter.
Solution Approach 2:
Each microinverter unit autonomously performs MPPT for its associated PV module without requiring complex centralized control. The distributed architecture allows each unit to self-manage its power conversion, simplifying individual device design while achieving system-level optimization through the collective action of multiple independent units.
3Device complexity
If conventional inverters are used with string design, then device complexity is reduced, but AC power harvest is degraded due to MPPT performance being limited by the least power producing modules
Solution Approach 1:
The inverter function is segmented and distributed to individual microinverter units, each associated with a specific PV module or small group of modules. This segmentation eliminates the string design constraint where the entire string's MPPT performance is limited by the weakest module. Each segmented unit can independently track its own maximum power point, ensuring optimal power harvest from every module regardless of variations in other modules' performance.
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
The system provides a simple, safe, and reliable power conversion solution with extended lifetime and upgradeability, reducing labor and maintenance costs while improving AC power harvest and enabling remote monitoring and control.
Implementation Method 1
Distributed sources of electrical energy such as solar photovoltaic modules, batteries, fuel cells and others generate direct current (DC) power, which must be converted to alternating current (AC) power for transmission and usage in residential and commercial settings.
Implementation Method 2
The MPPT process evaluates the PV module string output current-voltage curve on a continuous or sampled basis to determine the correct load voltage thus maximizing the string output power calculated as the string output voltage times current.
Implementation Method 3
solar photovoltaic modules, batteries, fuel cells and others generate direct current (DC) power
Data Source
AI summary
A system and apparatus for use in energy conversion. In one embodiment, the apparatus comprises at least one power converter for producing power at a first level while receiving an indicium of proper operation and, upon not receiving the indicium of proper operation, producing power at a second level, where the second level is less than the first level.