Energy Storage Converter Mode Switching for Grid Failure Support
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Solution Overview
Problem
Energy storage converters fail to provide voltage and frequency support and power for important or sensitive loads when the power grid fails.
Innovation Solution
Implementing a control method that switches between grid-connected mode for active power and reactive power decoupling control and island mode for virtual magnetic flux control, using proportional integral controllers and virtual synchronous generators to stabilize voltage and frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the energy storage converter operates in grid-connected mode with active power and reactive power decoupling control, then the balance of active power and reactive power is maintained according to scheduling instructions, but the converter cannot provide voltage and frequency support or power for critical loads when the power grid fails
Solution Approach 1:
The control system dynamically switches between grid-connected mode and island mode based on the operational status of the power grid. When the grid is normal, the converter operates in grid-connected mode with active power and reactive power decoupling control. When grid failure is detected, it automatically transitions to island mode with virtual magnetic flux control, enabling the system to adapt to different operating conditions and maintain reliability
Solution Approach 2:
The energy storage converter is designed to perform multiple functions through different control modes. In grid-connected mode, it maintains power balance and supports the grid. In island mode, it provides voltage and frequency support while powering critical and sensitive loads. This multi-functionality resolves the contradiction by enabling the single device to serve both grid support and independent power supply roles
2Reliability
If the energy storage converter adopts virtual magnetic flux control in island mode, then voltage and frequency support is quickly established for local loads, but the device complexity increases due to the need for mode switching and multiple control mechanisms
Solution Approach 1:
The control system employs dynamic mode switching between grid-connected and island modes based on grid status detection. The controller automatically selects the appropriate control strategy (active power/reactive power decoupling control or virtual magnetic flux control) according to the operational state, enabling the system to provide reliable electrical energy quality while managing complexity through intelligent automation
Solution Approach 2:
The system incorporates feedback mechanisms to detect power grid status and automatically adjust control modes. The controller monitors grid conditions and uses this feedback to switch between control strategies, ensuring that voltage and frequency support is provided when needed while maintaining systematic control that manages the complexity of multiple operating modes
Data Source
AI summary
An energy storage converter, a control method and device for the energy storage converter, and a computer readable storage medium are provided. The control method includes: obtaining an operation state of a power grid; under the condition that the power grid operates in a normal state, controlling the energy storage converter to operate in a grid-connected mode; and under the condition that the power grid operates in an abnormal state, controlling the energy storage converter to operate in an island mode. In the grid-connected mode, the energy storage converter uses active power and reactive power decoupling control. In the island mode, the energy storage converter uses virtual magnetic flux control.