Power Converter Swing Equation Tuning for RoCoF Ride-Through
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Solution Overview
Problem
Existing swing equations for power converters struggle to provide an acceptable response to both grid voltage phase jumps and Rate-of-Change-of-Frequency (RoCoF) events, often leading to over-current and current blocking, which prevents the converter from riding through such events without shutting down.
Innovation Solution
A method and system for adjusting swing equation parameters during RoCoF events by detecting consistent signs in differentiated frequency information and active power thresholds, allowing a RoCoF ride through by fine-tuning the swing equation parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the swing equation parameters are kept fixed for general operation, then the converter responds adequately to normal grid conditions, but the converter cannot ride through RoCoF events without current blocking
Solution Approach 1:
The patent implements dynamic adjustment of swing equation parameters based on detected grid conditions. The control system continuously monitors frequency and calculates RoCoF, then modifies swing equation parameters in real-time when RoCoF events are detected. This dynamic adaptation allows the converter to optimize its response characteristics for different operating conditions, enabling ride-through capability during RoCoF events while maintaining normal operation under standard conditions.
Solution Approach 2:
The patent specifically changes the parameters of the swing equation (such as inertia constant H and damping coefficient D) based on the detected RoCoF magnitude and direction. By adjusting these parameters dynamically, the converter can control its frequency response characteristics to match the grid conditions, preventing current blocking during RoCoF events while maintaining stable operation during normal conditions.
2Reliability
If the swing equation parameters are adjusted to improve RoCoF response, then the converter can ride through RoCoF events, but the response to grid voltage phase jumps becomes unacceptable
Solution Approach 1:
The control system dynamically switches between different swing equation parameter sets based on the detected grid event type. When a RoCoF event is detected through frequency derivative analysis, the system activates parameters optimized for frequency stability. When voltage phase jumps are detected, the system switches to parameters optimized for voltage synchronization. This dynamic parameter selection enables the converter to provide appropriate responses for different grid disturbances.
Solution Approach 2:
The patent implements distinct parameter configurations for different operating conditions: one set of swing equation parameters is optimized for RoCoF events (emphasizing frequency response), while another set is optimized for voltage phase jump events (emphasizing voltage synchronization). The control system selectively applies the appropriate parameter set based on real-time grid condition detection, ensuring optimal performance for each event type without compromising the other.
3Adaptability or versatility
If fixed swing equation parameters are used, then the control system is simple, but the converter cannot adapt to different grid events (RoCoF and phase jumps)
Solution Approach 1:
The patent pre-configures multiple sets of swing equation parameters, each optimized for specific grid event types (RoCoF events, voltage phase jumps, normal operation). The control system includes pre-programmed detection logic that identifies event types and automatically selects the appropriate parameter set. This preliminary preparation of parameter sets and detection algorithms enables rapid adaptation to different grid events without requiring complex real-time calculations or adjustments.
Solution Approach 2:
The control system continuously monitors grid frequency, calculates the rate of change of frequency, and compares it against threshold values to detect RoCoF events. Similarly, it monitors voltage phase to detect phase jumps. Based on this feedback from grid conditions, the system automatically adjusts swing equation parameters in real-time. This closed-loop feedback mechanism enables adaptive response to different grid events while keeping the control logic relatively simple and rule-based.
Data Source
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AI summary
Systems and methods for adjusting a controller for a power converter during a rate-of-change-of-frequency (RoCoF) event may include determining, based on first frequency information, a first RoCoF and a second RoCoF for the power converter; determining that the first RoCoF and the second RoCoF are both positive numbers or are both negative numbers; detecting a possible RoCoF event; comparing the first RoCoF to a positive RoCoF activation threshold when the first RoCoF is positive or to a negative RoCoF activation threshold when the first RoCoF is negative, and a power of the power converter to an upper or lower active power activation threshold; detecting, based on the threshold comparisons, a RoCoF event; and applying, during the RoCoF event, a RoCoF ride through.