PV Storage Bypass Switch for Power Loss Reduction
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Solution Overview
Problem
Conventional photovoltaic energy storage systems face high fabricating costs and significant power loss due to the need for multiple conversion stages when transferring energy between photovoltaic power generation and storage systems, especially when discharging power to the grid.
Innovation Solution
A photovoltaic energy storage system with a DC/DC conversion device including a bypass switch and a DC/DC converter, where the bypass switch is turned on when the output voltage of the photovoltaic array is below a threshold, allowing direct power transmission from the energy storage device to the inverter, reducing the need for additional conversion stages and lowering costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If multiple conversion stages are used in photovoltaic energy storage systems, then energy can be transferred between photovoltaic power generation and storage systems, but power loss increases and fabricating cost increases
Solution Approach 1:
The patent extracts and removes unnecessary DC/DC conversion stages from the traditional photovoltaic energy storage system. By directly connecting the photovoltaic array to the inverter's DC terminal, the system eliminates redundant conversion equipment, thereby reducing power loss and simplifying the overall system structure while maintaining the core energy conversion functionality.
Solution Approach 2:
The patent merges the photovoltaic array directly with the inverter by connecting the photovoltaic array's positive and negative terminals to the inverter's DC terminal. This integration eliminates the need for separate DC/DC conversion stages, reducing both power loss and system complexity while achieving efficient energy transfer.
2Ease of manufacture
If multiple conversion stages are used in photovoltaic energy storage systems, then energy conversion between different voltage levels can be achieved, but fabricating cost increases
Solution Approach 1:
The patent removes unnecessary DC/DC conversion equipment from the system, directly connecting the photovoltaic array to the inverter. This extraction of redundant components significantly reduces fabricating costs while maintaining the system's ability to perform energy conversion through the inverter's internal circuitry.
Solution Approach 2:
The patent combines the photovoltaic array and inverter into a more integrated configuration, eliminating separate DC/DC conversion stages. This merging reduces the total number of components that need to be manufactured and assembled, thereby lowering fabricating costs and simplifying the manufacturing process.
3Loss of energy
If DC/DC conversion device is always used, then voltage matching between energy storage device and inverter can be achieved, but power loss increases
Solution Approach 1:
The patent introduces a bypass switch that dynamically connects or disconnects the DC/DC conversion device based on real-time voltage conditions. When the photovoltaic array's output voltage matches the inverter's DC terminal voltage, the bypass switch closes to create a direct connection, eliminating power loss through the DC/DC converter. This dynamic adaptation maintains voltage matching capability while minimizing energy loss.
Solution Approach 2:
The patent extracts the DC/DC conversion function from being a permanent, always-active component and transforms it into a conditionally-used component. By using the bypass switch to selectively engage or disengage the DC/DC converter, the system removes unnecessary conversion operations that cause power loss while retaining the capability to perform voltage matching when needed.
4Loss of energy
If bypass switch is turned on for direct power transmission, then power loss is reduced, but system control complexity increases
Solution Approach 1:
The patent employs a control device that continuously monitors the output voltage of the photovoltaic array and the voltage at the inverter's DC terminal. Based on this feedback, the control device automatically determines whether to close the bypass switch to enable direct power transmission or to route power through the DC/DC converter. This feedback mechanism simplifies control by using straightforward voltage comparison logic rather than complex control algorithms.
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 configuration reduces power loss and fabrication costs by minimizing the number of conversion stages, enhancing system efficiency and power transmission efficiency, especially during low solar energy conditions or at night.
Implementation Method 1
a photovoltaic array device 4
Implementation Method 2
an inverter 3, a photovoltaic array device 4... The inverter includes a DC terminal and an AC terminal
Data Source
AI summary
A photovoltaic energy storage system includes an energy storage device, an inverter, a photovoltaic array device, a DC/DC conversion device and a controller. When an output voltage of the photovoltaic array device is greater than or equal to a predetermined threshold value, the photovoltaic energy storage system is operated in a first working mode. When the output voltage of the photovoltaic array device is lower than the predetermined threshold value, the photovoltaic energy storage system is operated in a second working mode. The DC/DC conversion device includes a bypass switch and a DC/DC converter. When the photovoltaic energy storage system is operated in the second working mode, the bypass switch is turned on and the DC/DC converter is disabled. Consequently, the electric power of the energy storage device is transmitted to the inverter through the bypass switch.