Backfeed Power Supply for Solar Systems
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Solution Overview
Problem
Solar power systems with tracking mechanisms face challenges in efficiently managing power distribution between solar collection systems and the AC power grid, particularly in maintaining optimal DC voltage levels to prevent backfeeding and ensure reliable operation of support devices.
Innovation Solution
A solar power system with a backfeed power supply mechanism that controls the flow of power between the AC power grid and the solar collection system based on DC voltage thresholds, using an inverter with input and backfeed controlled switches, and a transformer with windings to manage power flow and support tasks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the solar collection system is connected to the AC power grid without backfeed control, then power can be supplied to support devices during low generation periods, but backfeeding may occur when DC voltage exceeds threshold levels causing system instability
Solution Approach 1:
The system continuously monitors DC voltage levels and uses this feedback to control the operation of backfeed prevention devices. When DC voltage exceeds a predetermined threshold, the feedback mechanism activates switches to disconnect the solar collection system from the AC power grid, preventing backfeeding. This closed-loop control ensures system stability while allowing power sharing between solar generation and grid supply during normal operating conditions.
2Reliability
If backfeed prevention switches are installed to prevent harmful backfeeding, then system stability is improved, but device complexity increases due to additional controlled switches and control circuitry
Solution Approach 1:
The backfeed prevention device incorporates multiple functions within a single integrated system: it acts as a protective switch to prevent backfeeding, a power transfer switch to enable bidirectional power flow between solar collection and AC grid, and a control element that responds to voltage thresholds. By combining these functions into one device, the patent reduces overall system complexity compared to having separate components for each function.
Solution Approach 2:
The backfeed prevention device autonomously monitors DC voltage levels and automatically activates or deactivates based on predetermined threshold conditions without requiring external control signals. This self-service capability eliminates the need for complex external control circuitry, reducing device complexity while maintaining reliable backfeed prevention and power transfer functionality.
3Productivity
If DC voltage is maintained at high levels to maximize solar power generation, then energy production is improved, but the risk of backfeeding increases when voltage exceeds grid connection thresholds
Solution Approach 1:
The system takes preliminary action by continuously monitoring DC voltage levels and preparing to activate backfeed prevention switches before voltage reaches dangerous levels. When the voltage approaches the grid connection threshold, the control mechanism preemptively activates the switches to disconnect the solar collection system, preventing backfeeding before it can occur. This allows the system to operate at high voltage levels for maximum power generation while maintaining safety through advance protective action.
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
Ensures efficient power management by preventing backfeeding when DC voltage is above a threshold and providing grid power when below, enabling reliable operation of support devices and optimizing energy usage in solar power systems.
Implementation Method 1
a transformer with windings to manage power flow
Implementation Method 2
photovoltaic modules, thermal solar collector devices as well as concentrators for concentrating solar energy onto photovoltaic devices
Data Source
AI summary
A solar collection system may collect energy from the sun to generate electricity for distribution on an electrical grid. In addition to generating electricity, a solar collection system may include support devices such as motors, controllers, sensors, and other support devices to perform various tasks to allow the solar collection system to more effectively generate electricity. When the solar collection system is generating sufficient power, the support devices may be powered by the solar collection system. However, when the solar collection system is not generating sufficient power, the support devices may be powered by a backfeed power supply circuit coupled to the electrical grid.