Energy Storage Converter Control for Seamless Grid Switching
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Solution Overview
Problem
Energy storage systems experience electric energy quality fluctuations during on-grid and off-grid switching, leading to potential load tripping or device damage.
Innovation Solution
A method and device for on-grid and off-grid dispatch that determines given power and voltage based on previous load conditions, adjusts energy storage converter output parameters using direct-axis and quadrature-axis voltage adjustment parameters, and performs proportional integral adjustments to maintain seamless transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the converter control loop is switched during on-grid and off-grid process, then the energy storage system can provide power support to the load, but electric energy quality fluctuations occur during the switching process
Solution Approach 1:
The control method performs preliminary detection of grid status (voltage and current thresholds) before switching occurs. The converter control loop parameters are pre-adjusted based on predicted grid conditions, allowing the system to transition smoothly without sudden fluctuations in electric energy quality while maintaining power support capability.
Solution Approach 2:
The system continuously monitors grid voltage and current, load power consumption, and converter output parameters. Based on this feedback, the control method dynamically adjusts the converter control loop parameters during the on-grid and off-grid switching process, eliminating electric energy quality fluctuations while ensuring reliable power support to the load.
2Object-affected harmful factors
If the converter control loop parameters are adjusted during switching, then electric energy quality can be maintained, but the control system complexity increases
Solution Approach 1:
The control method adjusts specific converter control loop parameters (such as voltage threshold, current threshold, and power factor) based on the grid status and load conditions. By changing these parameters adaptively rather than redesigning the entire control system, the method maintains electric energy quality while minimizing the increase in control system complexity.
Data Source
AI summary
A method and a device for on-grid and off-grid dispatch, and an energy storage air-conditioning system are provided. The method for on-grid and off-grid dispatch includes: causing a load to be off-grid and causing an energy storage converter to supply power to the load after determining that grid is down; determining a given power and a given voltage according to a voltage and a current of the load obtained for the last time before the grid is down; and obtaining an actual voltage and an actual current outputted by the energy storage converter; and adjusting an output parameter of the energy storage converter according to the given power and the given voltage, as well as the actual voltage and the actual current outputted by the energy storage converter.