Voltage-Impressing Electrolysis Converter for Fast Frequency Response
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Solution Overview
Problem
Conventional electrolysis devices connected to AC voltage grids via current-impressing converters are not suitable for providing instantaneous balancing power or reserve due to delayed responses to frequency changes, which hinder their ability to stabilize grid frequency effectively.
Innovation Solution
Operating an electrolysis device with a converter in a voltage-impressing manner, allowing immediate changes in AC active power drawn from the AC voltage grid based on grid frequency changes, which are then passed on to the electrolyzer, enabling immediate response to frequency deviations and providing instantaneous reserve power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a current-impressing converter is used to connect the electrolysis device to the AC voltage grid, then the converter can operate with a predefined setpoint for DC power, but the response to frequency changes is delayed, making the device unsuitable for providing instantaneous balancing power
Solution Approach 1:
The patent inverts the conventional control approach by switching from current-impressing mode to voltage-impressing mode. Instead of controlling the converter through current setpoints that require frequency adaptation, the system controls the converter through voltage setpoints that respond immediately to frequency changes. This inversion of the control variable (from current to voltage) enables instantaneous response while maintaining reliable grid connection.
2Ease of operation
If the converter operates in current-impressing mode with frequency adaptation, then the control is stable, but the response time to frequency changes increases, preventing instantaneous reserve power provision
Solution Approach 1:
The patent changes the control parameter from current (I) to voltage (U). By switching the impressed parameter from current to voltage, the system achieves both stability and speed. The voltage-impressing mode maintains stable operation through proper voltage regulation while eliminating the frequency adaptation delay inherent in current-impressing mode, thereby achieving instantaneous response to frequency changes.
3Productivity
If the electrolysis device is operated at nominal power (50-100% of nominal power), then efficient electrolysis is maintained, but the device cannot provide instantaneous reserve power for grid frequency stabilization
Solution Approach 1:
The patent introduces dynamic control capability to the electrolysis device through voltage-impressing converter operation. The system can now dynamically adjust its power consumption in response to grid frequency changes while maintaining efficient electrolysis operation at nominal power during steady-state conditions. This dynamic adaptability allows the device to provide instantaneous reserve power without sacrificing electrolysis efficiency during normal operation.
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 approach allows for immediate stabilization of the grid frequency by enabling the electrolysis device to provide instantaneous reserve power, reducing the need for additional buffering measures and leveraging the inherent inertia of the electrolyzer for brief power changes, thus supporting grid stability without significant delays.
Implementation Method 1
The converter (12) is operated in a voltage-impressing manner, such that the AC active power which is drawn from the AC voltage grid (15) is immediately changed on the basis of a change and/or a rate of change of the grid frequency
Implementation Method 2
leveraging the inherent inertia of the electrolyzer for brief power changes
Implementation Method 3
an electrolysis device having a converter (12), in particular a voltage-source converter, and an electrolyzer (11)
Data Source
AI summary
A method for operating an electrolysis device, having a converter which is connected on an AC voltage side to an AC voltage grid via a decoupling inductance and draws an AC active power from the AC voltage grid, and an electrolyzer, which is connected to the converter on the DC voltage side, is provided. The method includes operating the electrolysis device, when a grid frequency corresponds to a nominal frequency of the ACT voltage grid and is substantially constant over a time period, with an electrical power which is between 50% and 100% of a nominal power of the electrolyzer, and operating the converter in a voltage-impressing manner, such that an AC active power drawn from the AC voltage grid is changed on the basis of a change and/or a rate of change of the grid frequency in the AC voltage grid.