Nonlinear Active Disturbance Rejection for Aircraft Grid Phase Angle Tracking
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Solution Overview
Problem
Current aircraft grid phase angle trackers struggle with high-accuracy tracking, especially under conditions of harmonic interference and frequency variations, leading to reduced stability and safety concerns.
Innovation Solution
A nonlinear active disturbance rejection method is employed to design a high-accuracy grid phase angle tracker, which models the aircraft grid, accounts for voltage amplitude imbalance, high harmonics, and DC bias, and uses a generalized integral nonlinear extended state observer to enhance tracking precision and convergence rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If proportional integral method or proportional integral differential method is used for grid phase angle tracking, then the tracking system is simple to implement, but the tracking accuracy deteriorates under harmonic interference and frequency variations
Solution Approach 1:
The patent changes the control parameter from fixed proportional integral gains to adaptive gains that vary with operating conditions. The nonlinear active disturbance rejection controller dynamically adjusts control parameters based on the actual grid state, enabling high accuracy under varying frequency and harmonic conditions while maintaining implementation feasibility through a systematic design framework.
Solution Approach 2:
The patent implements feedback through the active disturbance rejection mechanism that continuously monitors tracking error and adjusts control actions accordingly. The generalized integral nonlinear extended state observer provides feedback on system state and disturbance, enabling the controller to compensate for harmonic interference and frequency variations, thereby improving tracking accuracy without excessive complexity.
2Device complexity
If existing grid phase angle trackers are designed for single grid working frequency, then the controller design is simplified, but the tracking accuracy deteriorates when grid frequency varies within 360-800 Hz
Solution Approach 1:
The patent applies dynamics by designing a controller that adapts to changing operating conditions rather than being optimized for a fixed frequency. The nonlinear active disturbance rejection controller dynamically responds to frequency variations within 360-800 Hz, maintaining high tracking accuracy across the entire frequency range through continuous adaptation of control characteristics.
Solution Approach 2:
The patent achieves universality by designing a single controller that can handle multiple grid frequency conditions and harmonic disturbances simultaneously. The generalized integral nonlinear extended state observer and active disturbance rejection mechanism provide multi-functional capability to track phase angle accurately under varying frequency, harmonic interference, and DC bias conditions, eliminating the need for multiple specialized controllers.
3Object-affected harmful factors
If fast varying sinusoidal harmonic disturbances are present in the grid, then the grid quality deteriorates, but the existing tracking methods cannot well attenuate the harmonic disturbances
Solution Approach 1:
The patent converts the harmful effect of harmonic disturbances into a beneficial control opportunity. The active disturbance rejection mechanism treats harmonic disturbances as measurable disturbances and generates compensating control actions that cancel their effect on the phase angle tracking. By observing the distortion patterns caused by harmonics, the controller learns to counteract them, transforming the harmful disturbances into information for improving tracking reliability.
Solution Approach 2:
The patent introduces the generalized integral nonlinear extended state observer as an intermediary that processes grid voltage information and extracts disturbance components. This intermediary block separates the useful phase angle information from harmful harmonic disturbances, enabling the controller to track the true phase angle while rejecting the effects of fast varying sinusoidal harmonic disturbances, thereby improving tracking reliability under poor grid quality conditions.
Data Source
AI summary
The present invention belongs to the technical field of aviation electrics and electric power, and provides an aircraft grid phase angle tracker based on nonlinear active disturbance rejection, which is used to estimate the grid phase angle on AC side of an aircraft grid. A embedded generator in the aircraft grid is arranged inside a compressor of an aviation gas turbine engine, and the embedded generator is directly coupled with the aviation gas turbine engine so that the AC frequency of the embedded generator varies with the speed of the aviation gas turbine engine. The present invention applies the nonlinear active disturbance rejection technology to the phase angle tracking of the more electric aircraft grid, is simple in operation and high in accuracy, and can realize high-accuracy tracking of the grid phase angle. The method has certain extensibility and can be extended to other fields.