Hydraulic Pitch Drive Circuit for Regenerative Force Control
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Solution Overview
Problem
Existing hydraulic pitch drive systems for wind turbines face challenges in balancing efficiency, responsiveness, and cost while maintaining safety and reliability, with current solutions either reducing the lifespan of hydraulic components or increasing system complexity.
Innovation Solution
A hydraulic pitch drive system with a secondary extending operation mode that dynamically controls rod-side pressure using a second proportional valve, allowing for efficient operation under normal loads and temporary force-boost during high loads, thereby improving responsiveness and peak load handling without compromising efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic pitch drive systems use larger components and higher design pressure to handle peak loads, then reliability and safety are improved, but initial component cost and manufacturing complexity increase
Solution Approach 1:
The system dynamically adjusts the hydraulic circuit configuration based on operating conditions. During normal operation, the regenerative circuit is active, connecting the rod-side chamber to the piston-side chamber through a check valve, enabling efficient energy recovery. During peak load conditions, the system can bypass this regenerative path and use direct pump supply, allowing the same components to handle both efficient normal operation and high-demand scenarios without requiring oversizing for peak conditions alone
Solution Approach 2:
The system changes the effective hydraulic parameters (pressure, flow paths, circuit configuration) based on operational needs. The dual-circuit design allows switching between regenerative mode (with different pressure-flow characteristics) and direct supply mode, enabling the hydraulic components to operate optimally across a wide range of load conditions without requiring the conservative oversizing that would be needed for a single fixed configuration
2Productivity
If hydraulic pitch drive systems are designed for high responsiveness and peak load handling, then productivity and speed are improved, but component cost and system complexity increase
Solution Approach 1:
The hydraulic system employs dynamic circuit switching capability where the regenerative circuit can be activated or deactivated based on operational requirements. The check valve and associated control mechanisms enable the system to transition between regenerative operation (for normal responsiveness) and direct pump supply mode (for peak load handling), providing high productivity across different operating conditions without requiring permanently complex component arrangements
Solution Approach 2:
The hydraulic circuit is designed with multi-functionality, where the same basic components serve multiple purposes: the regenerative circuit provides both normal operation efficiency and can be bypassed for peak load handling, the check valve serves both as a one-way flow control and as a circuit switching element, and the pump system can supply both regenerative pressure and direct peak load pressure. This universal design reduces the need for dedicated components for each function, thereby reducing overall system complexity while maintaining high responsiveness and peak load capability
3Use of energy by moving object
If hydraulic pitch drive systems operate in regenerative mode during extending movement, then energy efficiency is improved, but force reserve during high load situations is reduced
Solution Approach 1:
The system dynamically switches between regenerative operation and direct supply operation based on load conditions. During normal extending movement, the regenerative circuit is active, connecting rod-side pressure to piston-side pressure through the check valve, achieving energy efficiency. When high load situations are detected or anticipated, the system can bypass the regenerative path and provide direct pump supply to the piston-side chamber, ensuring adequate force reserve is available when needed without permanently sacrificing efficiency
Solution Approach 2:
The system can anticipate high load situations and prepare by switching from regenerative mode to direct supply mode before the peak load occurs. The control system monitors operational parameters and can pre-activate the direct supply path, ensuring that force reserve is available when needed. This preliminary action allows the system to maintain energy efficiency during normal operation while being prepared to deliver maximum force when required
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 provides enhanced performance and cost-effectiveness by maintaining efficient operation under normal loads and providing a dynamic force reserve for high loads, allowing for smaller component sizing and reduced operational costs without sacrificing reliability or safety.
Implementation Method 1
The pitch rotation of each blade is actuated hydraulically by means of one or more, typically one or two linear hydraulic cylinders
Implementation Method 2
a hydraulic cylinder with a piston-side A and a rod-side B, the hydraulic cylinder being arranged to actuate blade pitch rotation
Implementation Method 3
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
Data Source
AI summary
A hydraulic pitch drive system for controlling a blade pitch angle of a wind turbine rotor has a hydraulic cylinder, for actuating blade pitch rotation, with a piston-side and rod-side. A first hydraulic proportional valve controls hydraulic fluid flow from a pressure port to the cylinder in response to a primary control signal. In an cylinder extending mode, the pressure port via the first hydraulic proportional valve is connected to the piston-side. The rod-side is connected to the pressure port via a non-return valve. A first control module provides the primary control signal in response to a pitch angle positioning request. A second hydraulic proportional valve controls hydraulic fluid flow from the rod-side to tank port independent of the first hydraulic valve, in response to a secondary control signal. A second control module provides the secondary control signal for controlling the second proportional valve in a hydraulic cylinder extending mode.