VSG Power Correction Feedback for Frequency Stability
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Solution Overview
Problem
Virtual Synchronous Generators (VSG) experience power oscillations due to improper setting of virtual inertia and damping coefficients, leading to instability in power systems.
Innovation Solution
A VSG frequency control method based on power correction, involving obtaining output power Pe(s), multiplying it by a transfer function G(s), and feeding it back to the frequency generation stage, with parameters τ1 and τ2 designed to suppress oscillations and enhance system stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If virtual inertia and damping coefficients are set to provide inertial support, then system frequency stability is improved, but power oscillations occur leading to system instability
Solution Approach 1:
The patent implements a power oscillation suppression controller that detects output power oscillations and feeds back corrective control signals to the VSG. The controller monitors the actual output power, compares it with the reference power, and adjusts the control parameters dynamically to suppress oscillations while maintaining inertial support functionality.
Solution Approach 2:
The patent dynamically adjusts control parameters including virtual inertia coefficient, damping coefficient, and power oscillation suppression coefficient based on system operating conditions. By changing these parameters adaptively, the system can provide inertial support when needed while suppressing power oscillations under different grid conditions.
2Reliability
If power correction feedback is added to suppress oscillations, then system stability is improved, but control loop complexity increases
Solution Approach 1:
The patent combines the power oscillation suppression function with the existing active power-frequency control loop by integrating the power correction feedback path. The correction stage is merged into the control structure, sharing common components such as the output power measurement and frequency generation stage, thereby reducing overall system complexity.
Solution Approach 2:
The power correction stage serves multiple functions: it suppresses power oscillations, provides inertial support, and maintains frequency stability. By designing the correction stage with universal functionality, the patent avoids adding separate dedicated systems for each function, thus controlling complexity while achieving multiple objectives.
Data Source
AI summary
VSG Frequency Control Method, Device and Storage Medium based on Power Correction, belonging to the field of power electronics technology, which addresses the problem of suppressing VSG output power oscillations. The technical solution of the present application corrects the output power Pe(s) and feeds the corrected value back to the control loop to suppress power oscillations. The transfer function of the power correction stage G(s) is flexible and can be configured with appropriate parameters according to the system's inherent phase margin. Additionally, principles for selecting the parameters of the correction coefficients τ1 and τ2 are also provided. The adjustment coefficients of the power correction stage, the values of τ1 and τ2 do not affect the effect of the steady-state gain during the transient process. The present application can not only suppress VSG output power oscillations, but also provide a larger inertial support, thereby improving the stability of the VSG system.