Self-Commutated Converter Control for Instant Grid Stabilization
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Solution Overview
Problem
Conventional methods for controlling power converters in renewable energy systems are insufficient for rapid grid stabilization, leading to instability in power grids with a high proportion of renewable energy generation plants, as they rely on slow control mechanisms and require complex filtering and current regulation, which are inadequate for modern grid demands.
Innovation Solution
A method for controlling self-commutated three-phase converters that determines current time-dependent electrical parameters to rotate previous control signals by an angle based on the current phase angle, allowing instantaneous control without filtering or current regulation, ensuring grid stability by emulating a constant resistance or power output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional filtering and dq-based control methods are used, then the control system is stable, but the response speed is slow and insufficient for rapid grid stabilization
Solution Approach 1:
The patent extracts and removes the filtering and current regulation components from the control system. By directly using measured grid voltages and currents without filtering, and by controlling converter currents directly without intermediate current regulation stages, the system achieves faster response speed while reducing structural complexity.
Solution Approach 2:
The patent applies preliminary action by pre-calculating the required converter currents based on the measured grid parameters and desired power output. The control currents are determined in advance using the formula i_c,k = (2/3) * (P_ref/u_d,k + Q_ref/u_q,k), allowing the converter to respond immediately to grid changes without waiting for filtering or multi-stage regulation.
2Productivity
If the proportion of renewable energy plants is increased, then clean energy generation is improved, but grid stability deteriorates due to lack of grid-stabilizing capabilities
Solution Approach 1:
The patent implements feedback by continuously measuring the actual grid voltages and currents, comparing them with the reference values, and adjusting the converter control currents in real-time. The control system uses the measured grid parameters to calculate the required converter currents that maintain constant active and reactive power output, thereby stabilizing the grid despite high renewable energy penetration.
Solution Approach 2:
The patent changes the control parameters from traditional voltage/frequency regulation to direct power control. By controlling the converter to maintain constant active power P and reactive power Q output regardless of grid voltage variations, the system provides grid-stabilizing capabilities that enable high proportions of renewable energy plants to operate reliably.
3Reliability
If slow control mechanisms are used in power converters, then the control system is simpler, but grid stabilization capability is insufficient for modern grid demands
Solution Approach 1:
The patent replaces the mechanical analog filtering and multi-stage current regulation systems with a direct digital control approach. By using digital calculations to determine converter currents based on measured grid parameters and desired power output, the system achieves fast response capability while simplifying the overall control structure, eliminating the need for physical filters and intermediate regulation stages.
Data Source
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Figure 3
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AI summary
The invention relates to a method for controlling a self-commutated converter (202, 316, 402), with at least one current electrical parameter of a section (302) being provided, with at least one current time parameter of the section (302) being determined from the current electrical parameter, at least one previous pointer setting signal is provided, the previous pointer setting signal being determined in a previous setting interval, the previous pointer setting signal being rotated by an angle, the angle being determined as a function of the determined current time parameter and the power converter (202, 316, 402) being a function of the rotated pointer setting signal is controlled.