DC-Coupled PV State Switching for Fast Battery Discharge Transition
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Solution Overview
Problem
The DC-coupled photovoltaic power generation system experiences slow response speeds due to offline switching of operating states, which affects its ability to adapt to varying energy conditions efficiently.
Innovation Solution
An online switching method and device that monitors photovoltaic energy levels to switch operating states dynamically, allowing the system to transition from grid-connected battery priority to nighttime battery discharge without shutting down, using direct current converters and inverters to manage power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If offline switching is used to ensure system stability, then system stability is improved, but response speed deteriorates
Solution Approach 1:
The patent implements dynamic online switching of operating states for the DC-coupled photovoltaic power generation system. The controller continuously monitors system parameters and dynamically transitions between different operating states (grid-connected photovoltaic priority, grid-connected battery priority, nighttime battery discharge) without requiring system shutdown. This dynamic approach resolves the contradiction by enabling both system stability through controlled transitions and fast response speed through real-time state changes.
2Reliability
If offline switching is used to switch operating states, then system stability is maintained, but system shutdown occurs
Solution Approach 1:
The patent enables continuous operation of the photovoltaic power generation system by implementing online switching between operating states. The controller manages power distribution continuously across different components (photovoltaic array, battery, load, grid) without interrupting system operation. This ensures both system stability through controlled power management and operational continuity by eliminating shutdowns during state transitions.
3Speed
If online switching is implemented to improve response speed, then response speed is improved, but system complexity increases
Solution Approach 1:
The patent employs a multi-functional controller that integrates multiple functions: monitoring photovoltaic energy levels, managing battery charge/discharge states, controlling power distribution to loads and grid, and executing operating state transitions. This universal controller consolidates what would otherwise be separate control systems, achieving fast online switching response while managing system complexity through functional integration rather than proliferation of separate components.
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 enhances the system's response speed, maximizes power utilization, and prevents system shutdowns due to overvoltage faults, improving operational reliability and user experience.
Implementation Method 1
A DC-coupled photovoltaic power generation system mainly operates in a grid-connected photovoltaic priority state
Data Source
AI summary
A DC-coupled photovoltaic power generation system, an operating state switching method and device of the DC-coupled photovoltaic power generation system are provided according to the present disclosure. The method includes: obtaining photovoltaic energy of the DC-coupled photovoltaic power generation system and determining whether the photovoltaic energy is sufficient, in a case that the DC-coupled photovoltaic power generation system operates in a grid-connected battery priority state; and if it is determined that the photovoltaic energy is insufficient, performing an online switchover operation, where the online switchover operation is used to switch the operating state of the DC-coupled photovoltaic power generation system from the grid-connected battery priority state to a nighttime battery discharge state.