Hydraulic Pitch Drive Control for Wind Turbine Peak Loads
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Solution Overview
Problem
Existing hydraulic pitch drive systems for wind turbines face challenges in efficiently managing blade pitch angles, leading to potential safety and reliability issues due to the need for predictive load management and the resulting complexity and cost.
Innovation Solution
A hydraulic pitch drive system that incorporates a second hydraulic proportional valve and a control module to dynamically control the rod-side pressure, allowing for efficient operation under normal loads and a force-boost mode during high load situations, thereby enhancing responsiveness and peak load handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a traditional hydraulic pitch drive system is used with regenerative operation mode, then energy efficiency is improved, but responsiveness and peak load handling capability deteriorate
Solution Approach 1:
The system dynamically switches between regenerative operation mode (for energy efficiency during normal operation) and force-boost mode (for rapid responsiveness during pitch events). The second hydraulic proportional valve enables dynamic adjustment of rod-side pressure, allowing the system to adapt its characteristics based on operational requirements.
Solution Approach 2:
The system changes the pressure parameter on the rod-side of the hydraulic cylinder by opening the second proportional valve to reduce pressure during force-boost mode, enabling rapid extension. During regenerative mode, the valve remains closed to maintain higher pressure for energy recovery.
2Loss of energy
If a traditional hydraulic pitch drive system is used with regenerative operation mode, then energy efficiency is improved, but peak load handling capability deteriorates
Solution Approach 1:
The system dynamically switches between regenerative operation mode (for energy efficiency during normal operation) and force-boost mode (for rapid responsiveness during pitch events). The second hydraulic proportional valve enables dynamic adjustment of rod-side pressure, allowing the system to adapt its characteristics based on operational requirements.
Solution Approach 2:
The system changes the pressure parameter on the rod-side of the hydraulic cylinder by opening the second proportional valve to reduce pressure during force-boost mode, enabling rapid extension. During regenerative mode, the valve remains closed to maintain higher pressure for energy recovery.
3Force
If an auxiliary pitch force subsystem is added to boost pitch force, then peak load handling capability is improved, but device complexity increases
Solution Approach 1:
The second hydraulic proportional valve serves multiple functions: it enables force-boost mode during pitch events, provides emergency stop capability by draining hydraulic fluid, and allows normal regenerative operation when closed. This multi-functionality reduces the need for separate auxiliary subsystems.
Solution Approach 2:
The second proportional valve acts as an intermediary element that modifies the existing hydraulic circuit to provide force-boost capability without requiring a completely separate auxiliary pitch force subsystem. It mediates between the pressure port and tank port to control pressure on the rod-side.
4Reliability
If predictive load management is implemented, then safety and reliability are improved, but device complexity increases
Solution Approach 1:
The second proportional valve serves as a simple intermediary device that provides force-boost capability on-demand without requiring complex predictive control systems. The valve can be controlled by a simple control module that responds to pitch angle requests or load conditions.
Solution Approach 2:
The system uses the existing hydraulic infrastructure and control module to provide force-boost capability, rather than requiring separate predictive load management systems. The control module leverages available information about pitch operations to activate force-boost mode when needed.
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 system achieves improved responsiveness and peak load handling capabilities while maintaining efficiency and reducing system costs, without compromising safety and reliability, allowing for continuous blade pitch control without the need for predictive load management.
Implementation Method 1
A correct dimensioning of the hydraulic components and design pressure of the hydraulic pitch drive system is considered crucial for safety, reliability, and efficiency of the operation of a wind turbine with adjustable blade pitch angle.
Implementation Method 2
a first hydraulic proportional valve V3 arranged for controlling a flow of hydraulic fluid from a pressure port P to the hydraulic cylinder in response to a primary control signal S3
Implementation Method 3
a second hydraulic proportional valve V4 arranged for controlling a flow of hydraulic fluid from the rod-side B to the tank port T independent of the first hydraulic valve V3, in response to a secondary control signal S4
Implementation Method 4
wherein the rod-side B of the hydraulic cylinder via a non-return valve V6 is connected to the pressure port P
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The present invention relates in one aspect to a hydraulic pitch drive system for controlling a blade pitch angle of a blade on a rotor of a wind turbine. The pitch drive system comprises a hydraulic cylinder with a piston-side A and a rod-side B. The hydraulic cylinder is arranged to actuate blade pitch rotation. The pitch drive system further comprises a first hydraulic proportional valve V3 arranged for controlling a flow of hydraulic fluid from a pressure port P to the hydraulic cylinder in response to a primary control signal S3; wherein in an extending mode of the hydraulic cylinder the pressure port P via the first hydraulic proportional valve V3 is connected to the piston-side A of the hydraulic cylinder. The rod-side B of the hydraulic cylinder is connected to the pressure port P via a non-return valve V6. The pitch drive system further comprises a first control module configured to provide the primary control signal S3 in response to a to a blade pitch angle positioning request. The pitch drive system further comprises a second hydraulic proportional valve V4 arranged for controlling a flow of hydraulic fluid from the rod-side B to the tank port T independent of the first hydraulic valve V3, in response to a secondary control signal S4; and a second control module configured to provide the secondary control signal S4 for controlling the second proportional valve V4 in an extending mode of the hydraulic cylinder according to a control scheme.