Electric Machine Dynamic Capacity Curve for Low-Speed Power Damping
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Solution Overview
Problem
Conventional static power capacity curves in wind turbines are overly conservative at low rotor speeds, leading to unexploited power damping and limitations in resonance speed avoidance, resulting in suboptimal power production and stability issues.
Innovation Solution
A dynamic capacity curve is introduced that continuously evaluates active damping and shifts based on damping, stability, and fatigue criteria, allowing for optimal power production across all operation regions by dynamically adjusting the maximum allowed power or torque levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a static power capacity curve is used to limit power production, then operational stability and material fatigue are prevented, but power production is reduced at low rotor speeds due to excessive conservatism
Solution Approach 1:
The patent transforms the static power capacity curve into a dynamic one by continuously adjusting the maximum allowed power level based on real-time damping criterion evaluations. This allows the system to adapt the power limit according to actual operating conditions, particularly at low rotor speeds where the static curve is overly conservative, thereby maintaining stability while improving power production.
Solution Approach 2:
The patent changes the parameter of the power capacity curve from a fixed static value to a dynamically variable value. By evaluating the damping criterion (which includes active power damping and active torque damping) in real-time and using it to shift the dynamic capacity curve, the system optimizes the balance between operational stability and power production across different operating conditions.
2Ease of operation
If a static power capacity curve is used, then the system is simple to operate, but unexploited power damping is lost at low speeds where damping requirements are below the damping budget
Solution Approach 1:
The patent implements a feedback mechanism where the damping criterion (including active power damping and torque damping) is continuously evaluated and fed back to adjust the dynamic capacity curve. This feedback loop enables the system to capture and utilize previously lost power damping at low speeds, converting it into useful power production while maintaining operational stability.
Solution Approach 2:
By making the power capacity curve dynamic rather than static, the system can respond to changing damping requirements in real-time. At low rotor speeds where the damping criterion is below the damping budget, the dynamic curve allows the system to exploit available damping capacity that would otherwise be lost, improving energy utilization without compromising simplicity of operation.
3Strength
If a static power capacity curve limits maximum operation power, then material stability is protected, but the resonance speed avoider cannot operate effectively at low speeds due to power limitations
Solution Approach 1:
The patent makes the power capacity curve dynamic, allowing it to shift towards the maximum allowed power level based on the damping criterion. This dynamic adjustment provides the resonance speed avoider with additional power headroom at low speeds where it is most needed, while still respecting material stability limits through the damping criterion evaluation that incorporates material fatigue considerations.
Solution Approach 2:
By changing the power capacity parameter from static to dynamic based on damping criterion evaluation, the system enables the resonance speed avoider to operate more effectively at low speeds. The damping criterion serves as a adaptive limit that protects material stability while allowing sufficient power for resonance avoidance maneuvers that would be constrained under a static capacity curve.
Data Source
AI summary
A method for operating an electric machine (in particular a wind turbine) having a generator with a rotor and a stator is provided. The method includes: i) evaluating an active damping applied to the electric machine, ii) estimating a damping criterion from the evaluated applied active damping, and iii) shifting a dynamic capacity curve towards a maximum allowed level. The maximum allowed level is based on the damping criterion and a first operation criterion and/or a second operation criterion. Furthermore, the dynamic capacity curve is a dynamic power capacity curve or a dynamic torque capacity curve.