Photovoltaic Current Balancing for Parallel Power Supply Units
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Solution Overview
Problem
In photovoltaic systems with parallel-connected power supply devices, inappropriate load distribution leads to uneven current distribution, causing thermal stresses and reducing the service life of the devices, thereby increasing operation and maintenance costs.
Innovation Solution
A photovoltaic system with DC/DC and DC/AC converters that adjust current output based on state parameters to ensure balanced load distribution by determining reference current values for each unit, using a system control unit to manage power supply units and adjust their output powers according to their actual capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If power supply devices are connected in parallel with simple average current control, then system complexity is reduced, but load distribution becomes uneven causing thermal stress
Solution Approach 1:
The patent implements a feedback mechanism where each power supply device reports its output current to a management device, which calculates a balanced reference current and sends control instructions back to adjust the output of each device. This closed-loop feedback system ensures even load distribution while maintaining system reliability.
Solution Approach 2:
The management device dynamically adjusts the reference current parameter for each power supply device based on real-time output current measurements. By changing the current parameter individually for each device rather than using a fixed average, the system achieves balanced load distribution and prevents thermal stress.
2Reliability
If individual current adjustment for each power supply device is implemented, then load distribution becomes balanced, but system complexity increases
Solution Approach 1:
The management device performs multiple functions: collecting current data from all power supply devices, calculating balanced reference currents, and sending control instructions. This multi-functional approach consolidates complexity into a single management device rather than requiring complex coordination between multiple devices.
Solution Approach 2:
The management device acts as an intermediary between power supply devices, centralizing the control logic and current balancing calculations. This intermediary approach simplifies the overall system architecture by providing a single point of coordination rather than requiring direct peer-to-peer communication between all devices.
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 ensures appropriate load distribution, prolongs the service life of power supply units, and reduces operation and maintenance costs by optimizing current and power distribution based on actual capabilities.
Implementation Method 1
Each of the at least two power supply units includes a DC/DC converter, and an input end of the DC/DC converter is connected to a direct current power source
Data Source
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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.