Power Conditioning Output Control for Frequency Stability
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Solution Overview
Problem
In power conditioning systems, the sudden shutdown and restart of photovoltaic and wind power generation devices during system failures cause sharp frequency fluctuations in isolated power systems, leading to potential deviations from predetermined frequency limits.
Innovation Solution
A power conditioning system with an output suppression control section that reduces output based on system fluctuations and a return control section that increases output in a variable return pattern, as instructed by external information, to minimize frequency deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power sources are shut off for a fixed time to protect devices during system failure, then device protection is achieved, but intensive simultaneous return causes sharp frequency changes in isolated power systems
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed, static return timing to a dynamic, flexible return pattern. The return timing is adjusted based on system conditions, allowing the power conditioning system to adapt its restart schedule to current grid status, thereby avoiding simultaneous returns that cause frequency instability while maintaining device protection protocols.
Solution Approach 2:
The patent implements preliminary action by calculating and determining return patterns in advance before system failure occurs. The control equipment pre-computes multiple return patterns based on historical data and system characteristics, selecting the most appropriate pattern when failure occurs. This advance preparation enables optimized return timing that prevents frequency instability without compromising device protection.
2Ease of operation
If power conditioning systems return to operation at fixed timing after shutdown, then operational simplicity is maintained, but supply-and-demand imbalance causes frequency deviation from limits
Solution Approach 1:
The patent applies parameter changes by modifying the return timing parameter from a fixed value to a variable determined by system conditions. The control equipment adjusts the return pattern parameters based on power system state, load conditions, and generation availability, thereby maintaining frequency stability while preserving ease of operation through automated parameter optimization.
Solution Approach 2:
The patent implements feedback by continuously monitoring system conditions and using this information to adjust return patterns. The control equipment receives real-time data on power supply and demand status, and uses this feedback to select or modify return patterns that will minimize frequency deviation, thus maintaining both operational simplicity and frequency stability.
Data Source
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AI summary
A command system of a power conditioning system of the present invention receives return pattern information including a time instance and an upper output limit, and issues a command with respect to the upper output limit of the power conditioning system, the return pattern information being for preventing the frequency of an isolated power system, which is calculated by a planning server, from causing a sharp change.