Photovoltaic Current Sharing Control for Parallel Power Units
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In photovoltaic systems with parallel-connected power supply devices, inappropriate load distribution leads to uneven current distribution, causing thermal stress and reducing the service life of some devices, thereby increasing maintenance costs.
Innovation Solution
A photovoltaic system with DC/DC converters and a DC/AC converter that adjusts current output power based on actual capabilities and state parameters of each unit, ensuring balanced output powers and preventing overloading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If power supply devices are connected in parallel on a same bus, then the power supply capacity is increased, but the load distribution becomes uneven causing thermal stress and reduced service life
Solution Approach 1:
The patent implements a feedback control mechanism where the master device collects power supply current data from all parallel-connected devices, calculates an average current reference value, and distributes it back to each device. Each device then adjusts its output based on the difference between its actual current and the reference value, creating a closed-loop feedback system that automatically balances load distribution and prevents thermal stress accumulation.
Solution Approach 2:
The patent dynamically adjusts the operating parameters (specifically the power supply current) of each parallel-connected device based on real-time monitoring data. By changing the current reference value for each device according to its actual performance and the system's average load, the system optimizes parameter distribution to achieve balanced load sharing while maintaining high power supply capacity.
2Ease of operation
If average current reference value is calculated and distributed to parallel devices, then the control simplicity is improved, but the load distribution appropriateness deteriorates due to parameter differences
Solution Approach 1:
The feedback mechanism continuously monitors the actual power supply current of each device and uses this information to adjust the current reference value dynamically. This closed-loop approach maintains control simplicity while achieving precise load distribution by compensating for parameter differences through real-time adjustments rather than relying on fixed predetermined values.
Solution Approach 2:
The patent transitions from a static average current reference value to a dynamic adjustment mechanism. The current reference value for each device is no longer fixed but changes continuously based on real-time monitoring data, allowing the system to adapt to parameter differences and achieve appropriate load distribution while maintaining ease of operation through automated dynamic control.
Data Source
AI summary
This application provides a photovoltaic system and a power supply current control method thereof. The photovoltaic system includes a direct current bus and at least two power supply units connected in parallel to the direct current bus. The power supply current control method of a photovoltaic system includes: obtaining a current power supply state parameter of each of the at least two power supply units, determining a reference power supply current value of each power supply unit based on the current power supply state parameter of each power supply unit, and adjusting a current supply power of each power supply unit based on the reference power supply current value of each power supply unit. According to this application, appropriate load distribution between power supply units can be ensured, and applicability is high.