IPM Wind Turbine Generator Non-Linear Control Compensation
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Solution Overview
Problem
Interior permanent magnet (IPM) wind turbine generators face challenges in constructing a linear power control system due to their non-linear nature, leading to unpredictable dynamic response and stability issues, especially with parameter variations and saturation, which affects steady-state performance.
Innovation Solution
A method is introduced to linearize the IPM power control system by adding a non-linear compensation unit that inverts the IPM non-linear power equation, using look-up tables or polynomial curves to generate field power stator flux or current references, and applying minimal copper loss and voltage limiting constraints to ensure stability and efficiency across varying operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If IPM generator operates with non-linear power generation characteristics, then power density is enhanced, but control linearity deteriorates making predictable dynamic response difficult to achieve
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting control parameters based on operating conditions. The controller modifies control parameters such as current references and voltage commands in real-time to compensate for non-linear effects, enabling the system to maintain predictable dynamic response across varying operating points while preserving the high power density characteristics of the IPM generator
Solution Approach 2:
The patent employs inversion by reversing the conventional control approach. Instead of attempting to control the non-linear IPM generator directly, the system inverts the non-linear power generation characteristics and applies compensating signals. This inversion strategy transforms the unpredictable non-linear behavior into a controllable system with predictable dynamic response, effectively resolving the contradiction between maintaining power density and achieving control linearity
2Reliability
If 2-dimensional look-up tables or polynomial functions are used for control, then steady state performance is improved, but sudden changes in current reference signals occur leading to stability issues
Solution Approach 1:
The patent applies dynamics by transitioning from static look-up tables to a dynamic control approach. The controller continuously adapts control parameters based on real-time operating conditions, enabling smooth transitions between different operating points. This dynamic adaptation eliminates the sudden jumps in current reference signals that occur with fixed look-up tables, thereby maintaining both steady-state performance and system stability
Solution Approach 2:
The patent introduces an intermediary control layer that mediates between the desired power output and the actual generator response. This intermediary controller processes the power reference signal and generates smoothed current references that account for system dynamics and constraints. By acting as an intermediary, this layer prevents direct transmission of abrupt reference changes to the generator, thereby eliminating stability issues while maintaining steady-state performance
3Power
If field weakening operation is applied above partial field weakening speed, then voltage limiting is achieved, but parameter variation due to saturation and temperature change causes deterioration of steady state performance
Solution Approach 1:
The patent applies feedback by continuously monitoring operating parameters such as current, voltage, temperature, and magnetic saturation levels. The controller uses this feedback information to dynamically adjust control parameters during field weakening operation, compensating for parameter variations caused by saturation and temperature changes. This feedback mechanism ensures that voltage limiting is achieved while maintaining steady-state performance across varying operating conditions
Solution Approach 2:
The patent employs preliminary action by pre-calculating and storing optimal control parameter mappings that account for expected parameter variations due to saturation and temperature changes. Before entering field weakening operation, the system prepares compensated control parameter sets that anticipate these variations. This preliminary preparation enables the controller to maintain accurate steady-state performance even as operating conditions change during field weakening
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The linearized power control system allows for predictable dynamic response and stability at all operating conditions, ensuring maximum efficiency and adaptability to parameter changes, enabling smooth transitions between control modes and maintaining system stability.
Implementation Method 1
a wind turbine generator converting mechanical energy to electrical energy
Implementation Method 2
The magnet field power (denoted as FP) is generated by the interaction of magnet field and the stator flux or current perpendicular to it
Data Source
AI summary
A method of controlling a wind turbine generator is provided, the wind turbine generator converting mechanical energy to electrical. The method comprises: determining an electromagnetic power reference representing the electromagnetic power generated by the wind turbine generator, wherein the electromagnetic power reference is determined based on a desired output of the wind turbine generator; controlling the electrical power generated by the wind turbine generator using a control signal, wherein the control signal is derived from the electromagnetic power reference and is modified in dependence on an inverse power function of the wind turbine generator by incorporating minimal copper loss constraint and stator voltage limiting constraint such that non-linearity of the wind turbine generator plant is compensated in the control loop and it operates at its maximum efficiency. One effect of the method is that classical linear control loop design can be employed in spite of the plant being a non-linear identity.