PV Array Backfeed Heating for Snow and Ice Removal
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Solution Overview
Problem
Snow and ice accumulation on photovoltaic (PV) modules significantly reduces power generation in inclement weather, necessitating an efficient method to clear these obstructions without manual intervention.
Innovation Solution
A power generation system that employs an inverter to apply a backfeed voltage to PV modules, monitored by current sensors to ensure the current does not exceed safety thresholds, dynamically adjusting the voltage to melt snow and ice while maintaining online PV modules' surface temperatures and compensating for offline modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If manual snow and ice removal methods are used on PV modules, then the obstruction is physically cleared, but labor costs increase and system downtime occurs
Solution Approach 1:
The PV modules automatically melt snow and ice through self-heating when backfeed voltage is applied, eliminating the need for manual removal operations. The system uses its own electrical infrastructure to perform the clearing function without external human intervention or specialized equipment.
Solution Approach 2:
The patent replaces mechanical snow removal methods (manual scraping, brushing, or mechanical clearing devices) with an electrical heating approach. By applying backfeed voltage to melt the snow and ice, the system substitutes physical mechanical action with thermal energy, achieving obstruction removal without mechanical contact.
2Speed
If high voltage is applied to melt snow and ice quickly, then melting speed increases, but risk of damaging PV modules increases
Solution Approach 1:
The backfeed voltage is dynamically adjusted based on real-time monitoring of current and power consumption. The system starts with a predetermined voltage and modifies it during operation to maintain current below the safety threshold, optimizing both melting speed and module protection through continuous adaptation.
Solution Approach 2:
The system incorporates feedback control by monitoring current data from sensors and using this information to adjust the backfeed voltage. The controller receives current measurements and modifies the voltage output to ensure safe operation, creating a closed-loop control system that balances melting effectiveness with module safety.
Solution Approach 3:
The patent changes the electrical parameters (voltage and current) of the backfeed signal to optimize the melting process. By adjusting these parameters within safe limits and monitoring their effects in real-time, the system achieves effective snow and ice removal while preventing damage to the PV modules.
3Stability of the object's composition
If backfeed voltage is applied to all PV modules simultaneously, then uniform heating is achieved, but current overload occurs when some modules are offline
Solution Approach 1:
The system applies backfeed voltage selectively to online PV modules rather than attempting to heat all modules uniformly. By identifying which modules are currently operational and directing heating only to those, the system avoids overloading the electrical circuit while still achieving effective snow and ice removal where needed.
Solution Approach 2:
The patent segments the PV array into online and offline modules, applying backfeed voltage only to the online segments. This segmentation allows the system to manage current distribution effectively, preventing overload by excluding non-functional modules from the heating circuit while maintaining uniform temperature distribution among active modules.
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
Effectively melts snow and ice on PV modules without physical contact, maintaining power generation efficiency and extending system lifespan by preventing damage from excessive current.
Implementation Method 1
Current flowing to the corresponding set of PV modules is about equal to a current flowing to each of the first subset of strings of PV modules that are online, such that a surface temperature of each PV module in the first subset of strings of PV modules is increased
Data Source
AI summary
A controller of a power generation system provides, in response to a request or a determination to initiate a heating mode for a photovoltaic (PV) array, a first instruction to an inverter coupled between the PV array and a power grid to apply an initial backfeed voltage on PV modules of the PV array. The PV array comprises a plurality of strings of PV modules coupled in parallel, and a first subset of the strings of PV modules are online and a second subset of the strings of PV modules are offline. The controller monitors current data from a set of current sensors that each measure current provided from a corresponding set of strings of PV modules of the plurality of strings of PV modules of the PV array. The controller also provides a second command to the inverter to adjust the backfeed voltage.