Variable Flow Hydraulic Circuit for Wind Turbine Pitch Systems
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Solution Overview
Problem
Existing hydraulic circuits for wind turbines face challenges in providing a continuously variable flow efficiently, with solutions like fixed or variable displacement pumps being complex, energy-inefficient, or having reduced lifetimes and increased response times.
Innovation Solution
A hydraulic circuit utilizing a fixed displacement pump driven by a fixed or variable speed motor, combined with a proportional bypass valve that controls the output flow from zero to full flow, allowing for continuous variation and faster response times, while maintaining mechanical simplicity and reducing system costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a variable displacement pump is used to provide continuously variable flow, then the flow control capability is improved, but the device complexity increases and response time increases
Solution Approach 1:
The system separates the flow control function from the pump itself. The fixed displacement pump handles flow generation while a bypass valve handles flow regulation, dividing the complex variable displacement pump function into simpler separate components.
Solution Approach 2:
A bypass valve is introduced as an intermediary component between the fixed displacement pump and the consumer circuit. This mediator enables continuous flow control without requiring the pump itself to be complex or variable displacement.
2Adaptability or versatility
If a variable displacement pump is used to provide continuously variable flow, then the flow control capability is improved, but the reliability decreases due to reduced lifetime
Solution Approach 1:
Instead of making the pump variable displacement to achieve flow control, the invention inverts the approach by using a fixed displacement pump with a bypass valve. This reverses the conventional wisdom that flow control must come from the pump itself.
Solution Approach 2:
The bypass valve is a simpler, more reliable component compared to variable displacement pump mechanisms. By using this simpler component for control, the system trades a potentially shorter-lived control element for the reliability of the main pump.
3Adaptability or versatility
If a fixed displacement pump with on/off bypass valve and accumulators is used, then the flow control capability is improved, but the energy efficiency decreases
Solution Approach 1:
The bypass valve provides partial flow control by allowing continuous adjustment from zero to full flow, eliminating the need for excessive energy consumption associated with starting and stopping the pump or dealing with pressure fluctuations from accumulators.
Solution Approach 2:
The continuous adjustment capability of the bypass valve maintains steady flow without interruption or energy-wasting cycles, unlike on/off valve systems that require repeated startup and accumulation cycles.
4Adaptability or versatility
If a fixed displacement pump with variable speed motor is used, then the flow control capability is improved, but the device complexity increases
Solution Approach 1:
The invention extracts the speed control complexity from the system by using a fixed speed motor and instead implementing flow control through the bypass valve, separating the motor function from the flow regulation function.
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
This configuration enables continuous flow control from zero to full flow, reduces response time, lowers production costs, and enhances reliability, particularly beneficial for wind turbine pitch systems by simplifying components and reducing loads on structural components.
Implementation Method 1
a bypass valve (150) including a valve input (151) hydraulically connected to the delivery output (112) of the fixed displacement pump (110), wherein the bypass valve (150) includes a variable opening for controlling the output flow delivered by the fixed displacement pump (110) towards the consumer circuit(s)
Data Source
AI summary
A hydraulic circuit for a wind turbine is provided. The hydraulic circuit includes: a fixed displacement pump including a suction input and a delivery output, a pump motor for driving the fixed displacement pump, a pressure line hydraulically connected to the delivery output of the fixed displacement pump for delivering an output flow and/or an output pressure generated by the fixed displacement pump towards at least a consumer circuit, a bypass valve including a valve input hydraulically connected to the delivery output of the fixed displacement pump, wherein the bypass valve includes a variable opening for controlling the output flow or the output pressure delivered by the fixed displacement pump towards the consumer circuit(s).