Solar PV Inverter Redundancy via DC Bus Power Rerouting
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Solution Overview
Problem
Inverter failure in solar photovoltaic systems leads to significant energy loss, particularly in central and string inverter systems, as it can cause the entire system to lose the opportunity to harvest energy, while in micro-inverter systems, energy loss is localized but still substantial due to downtime and the number of failures.
Innovation Solution
A solar photovoltaic power generation system is designed with a plurality of solar PV panels connected to power conditioning units and a dc power distribution bus, where fault detectors in power distribution controllers reroute dc power from faulty inverters to functioning ones, ensuring energy is shared and harvested efficiently, even in the event of inverter failure, using switched connections and diodes to manage power distribution and communication for fault detection and data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a central or string inverter system is used to consolidate power conditioning, then system complexity is reduced and cost is lowered, but the entire system loses energy harvesting capability when the inverter fails
Solution Approach 1:
The system segments the power conditioning function by distributing multiple independent inverters across different locations, each capable of operating autonomously. This allows the system to maintain energy harvesting capability even when individual inverters fail, resolving the contradiction between simplified architecture and system reliability.
Solution Approach 2:
Each inverter is equipped with local fault detection and isolation capabilities, allowing the system to maintain operational quality in healthy segments while isolating failures locally. This ensures that failure in one segment does not propagate to the entire system.
2Reliability
If a micro-inverter system is used to localise energy harvest, then system reliability is improved, but energy loss due to failure remains significant depending on down time and number of failures
Solution Approach 1:
The system merges previously isolated inverter segments through a DC distribution bus, allowing inverters to share and redistribute power. When one inverter fails, others can compensate by harvesting and distributing its lost energy, significantly reducing overall energy loss while maintaining reliability.
Solution Approach 2:
The system implements real-time monitoring and control where inverters detect faults in other segments and automatically adjust their operation to compensate. This feedback mechanism ensures rapid response to failures, minimizing downtime and energy loss.
3Reliability
If inverters are isolated and operate independently, then failure impact is localised, but the system cannot share or redistribute power to compensate for failures
Solution Approach 1:
The DC distribution bus provides multi-functionality by serving as both a power distribution medium and a fault compensation mechanism. It enables inverters to perform their primary power conditioning function while also facilitating inter-inverter power sharing and failure compensation, resolving the contradiction between isolation and productivity.
Data Source
AI summary
Improved techniques for photovoltaic power generation are described. Inverter failure is can be a significant problem in solar photovoltaic systems as it can lead to loss of opportunity to harvest energy. A solar photovoltaic (PV) power generation system is described comprising solar PV panels and power conditioning units. A dc power distribution bus is coupled to the solar PV panels and the power conditioning units to switchably share dc power from the solar PV panels between the power conditioning units. Power distribution controllers detect a faulty power conditioning unit and reroute power from a solar PV panel coupled to the faulty power conditioning unit to other power conditioning units via the dc distribution bus.