Grid Interconnection Phase Synchronization for Seamless Power Transfer
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Solution Overview
Problem
Conventional grid interconnection systems experience power interruptions when switching back to commercial power supplies after a failure, as they stop supplying power from storage batteries before starting commercial power supply.
Innovation Solution
A grid interconnection system with a power conversion device and interconnection control device that synchronizes the voltage phase and frequency of power from the storage battery with the commercial power supply, allowing seamless transition without interrupting power to the load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the supply of power from the storage battery is stopped before starting the supply of power from the commercial power supply, then the switching from storage battery power to commercial power supply is achieved, but the supply of power to the load is interrupted
Solution Approach 1:
The system performs preliminary synchronization of voltage phase and frequency of the storage battery power with the commercial power supply before switching. The interconnection control device adjusts the storage battery power output to match the commercial power supply parameters in advance, ensuring that when the switch occurs, both power sources are already synchronized, thus preventing power interruption and eliminating the need for complex sequential switching control
Solution Approach 2:
The system maintains continuous power supply to the load during the transition from storage battery power to commercial power supply. By synchronizing the voltage phase and frequency before switching and using make-before-break switching logic, the power flow to the load remains uninterrupted, ensuring continuous useful action throughout the power source transition
2Reliability
If the voltage phase of power from the storage battery is synchronized with the voltage phase of power from the commercial power supply, then the supply of power can be switched without interruption, but the control complexity increases
Solution Approach 1:
The interconnection control device continuously monitors the voltage phase and frequency of both the storage battery power and the commercial power supply, and adjusts the storage battery power output based on this feedback. This closed-loop control ensures that the voltage phases remain synchronized during the transition, achieving seamless power switching through real-time parameter matching
Solution Approach 2:
The system dynamically adjusts the voltage phase and frequency parameters of the storage battery power output to match the commercial power supply parameters. By changing these electrical parameters in real-time through power conversion control, the system achieves phase synchronization and enables uninterrupted power transition
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 continuous power supply to loads by smoothly switching from storage battery power to commercial power supply during restoration, preventing interruptions and voltage fluctuations.
Implementation Method 1
a power conversion device that converts power from the storage battery into AC
Data Source
AI summary
A grid interconnection system for a power grid includes: a storage battery; a power conversion device that converts power from the storage battery into AC; and an interconnection control device that supplies power from a commercial power supply to a load and supplies power from the power conversion device to the load when the commercial power supply fails. When the commercial power supply is restored, the interconnection control device starts supply of power from the commercial power supply to the load, and stops supply of power from the power conversion device to the load after the supply of power from the commercial power supply to the load is started.