Virtual Inertia Converter Control for Grid Frequency Stability
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Solution Overview
Problem
The integration of renewable energy sources like PV solar panels and wind turbines into electrical grids, which are traditionally dominated by synchronous generators, leads to instability and frequency swings due to the lack of inertia and fault current capability in inverter-based resources, necessitating improved control methods for power converters.
Innovation Solution
Implementing a Virtual Synchronous Machine (VSM) controller with energy storage to mimic the behavior of synchronous generators, including virtual impedance and inertia models, and using a feedforward control path to enhance the control of power converters, allowing them to respond dynamically to grid disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If inverter-based resources are used to replace synchronous generators, then renewable energy integration is improved, but grid stability and frequency control deteriorate due to lack of inertia
Solution Approach 1:
The patent creates a virtual copy of synchronous generator inertia behavior through control algorithms. The VSM controller replicates the inertial response characteristics of physical SGs by calculating and applying virtual inertia signals based on frequency deviations, enabling IBRs to mimic the stabilizing effects of traditional generators without requiring actual rotating mass.
Solution Approach 2:
The patent replaces the mechanical inertia of synchronous generators with an electrical control-based virtual inertia system. Instead of relying on physical rotating mass to provide inertial support, the system uses power electronic converters with control algorithms that generate inertial responses through electrical signals, substituting mechanical physics with electronic control.
2Stability of the object's composition
If Grid-Forming Inverter control is implemented, then grid stiffness is improved, but transient current stability deteriorates during grid disturbances
Solution Approach 1:
The patent applies preliminary anti-action by using the virtual impedance controller to pre-establish a stabilizing influence before transient disturbances occur. The controller continuously maintains virtual impedance parameters that counteract potential instability, and during disturbances, this pre-configured virtual impedance immediately acts to limit transient currents and stabilize the grid-forming inverter's output.
3Stability of the object's composition
If Virtual Synchronous Machine controller is used, then inertia response is improved, but control system complexity increases
Solution Approach 1:
The patent implements a universal control platform where the VSM controller integrates multiple functions including voltage control, frequency control, reactive power control, and inertial response within a single unified system. This multi-functional approach consolidates what would otherwise require separate control systems, reducing overall complexity while providing comprehensive grid support capabilities.
Data Source
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AI summary
The present disclosure relates to a method for controlling a power converter coupled to an electrical grid. The method comprises obtaining an output power of the power converter, an electrical parameterof the power converter, and an electrical parameter of the electrical grid; determining a power control error based on the output power of the power converter and a reference power; determining a rotational frequency of an inertia model based on an inertia model with the power control error as an input, wherein the inertia model is a mathematical model of the inertia of a machine; determining a phase angle based on the rotational frequency of the inertia model and on at least one control signal generated by at least one parameter following at least one control path different from a control path including the inertia model, wherein the phase angle is a target angle between the electrical parameter of the power converter and the electrical parameter of the electrical grid; and controlling the power converter based on the phase angle. The present disclosure also relates to a corresponding device and computer-readable medium.