Photovoltaic System Power Command Margin Control
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Solution Overview
Problem
Grid-connected photovoltaic systems face inefficiencies in charging and discharging due to the need for a margin in power commands, leading to cost losses when the margin is too small and reduced efficiency when it is too large, while also omitting the potential for maximizing energy transfer between the solar cell array and the external power grid.
Innovation Solution
A photovoltaic system with a power management device that adjusts the valid power command based on the reverse power from the external grid, determining the command value by either using the solar cell array's power generation amount alone or subtracting the reverse power from it, thereby optimizing energy storage and discharge efficiency without unnecessary cost losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a margin is added to the power command to prevent cost loss, then reliability is improved, but charging and discharging efficiency deteriorates
Solution Approach 1:
The power management device dynamically adjusts the power command margin based on real-time system state. When the solar cell array can meet the valid power command without external grid power, no margin is added. When external grid power is needed, an appropriate margin is added to prevent cost loss. This dynamic adjustment resolves the contradiction by making the margin adaptive rather than fixed.
Solution Approach 2:
The invention changes the parameter of power command margin based on operating conditions. The power management device calculates whether to add margin by comparing the valid power command with the power generation capability of the solar cell array and the power supply capability of the external grid. This parameter change strategy allows the system to optimize between reliability and efficiency under different conditions.
2Reliability
If a large margin is given to the power command, then reliability is improved, but energy efficiency deteriorates
Solution Approach 1:
The power management device uses feedback from the system state to determine the appropriate margin. It continuously monitors the valid power command, solar cell array generation capability, and external grid power supply capability. Based on this feedback, it decides whether to add margin to the power command, ensuring that margin is only added when necessary to prevent grid power usage for charging, thereby maintaining energy efficiency.
3Productivity
If the margin is set too small, then energy efficiency is improved, but cost loss occurs
Solution Approach 1:
The system dynamically determines the margin size based on real-time conditions rather than using a fixed small margin. When the solar cell array can meet the power demand, no margin is added, maintaining high charging efficiency. When the array cannot meet the demand and grid power would be used for charging, an appropriate margin is added to prevent cost loss. This dynamic approach resolves the contradiction between efficiency and cost prevention.
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 maximizes charging and discharging efficiency while minimizing cost losses by dynamically adjusting the power command in real-time, ensuring efficient energy transfer and profit optimization.
Implementation Method 1
a solar cell array configured to convert solar energy into power
Data Source
AI summary
A photovoltaic system and a control method therefor are disclosed. A photovoltaic system according to an embodiment of the present disclosure comprises: a solar cell array for converting solar energy into electric power; a power management device for monitoring the power generation amount of the solar cell array and the reverse power from an external power grid; an energy storage device charged by receiving the electric power produced by the solar cell array or the power of the external power grid; and a power control device for supplying, to the energy storage device, the electric power generated by the solar cell array or the power of the external power grid in response to a valid power command, wherein the power management device generates the valid power command which has different values according to whether the reverse power is generated by the external power grid.