Hydraulic-Pneumatic CVT Speed Control for Wind Turbine Generators
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Solution Overview
Problem
Existing continuous variable transmissions (CVT) are mechanically complex and expensive, with limited modes of control, which hinders efficient micro-level speed control and power generation optimization in wind or water turbines.
Innovation Solution
A pneumatically-assisted hydraulic CVT system that eliminates the need for pumps, pistons, gears, belts, pulleys, clutches, or valves for speed control, utilizing a programmable logic controller to manage hydraulic and pneumatic systems for variable speed control and energy storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional mechanical CVT components (pumps, pistons, gears, belts, pulleys, clutches, valves) are used for speed control, then macro level speed adjustment is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent removes traditional mechanical CVT components (pumps, pistons, gears, belts, pulleys, clutches, valves) from the system. Instead of using complex mechanical assemblies, the invention extracts only the essential function of speed control and achieves it through direct hydraulic coupling between turbine and generator, eliminating unnecessary intermediate components.
Solution Approach 2:
The patent replaces the traditional mechanical control system with a hydraulic control system. By using hydraulic fluid pressure and flow to control the coupling between turbine and generator, the system substitutes mechanical components with hydraulic actuators, reducing mechanical complexity while maintaining speed control capability.
2Measurement precision
If traditional CVT control methods are used, then basic speed regulation is achieved, but micro level speed control precision is limited
Solution Approach 1:
The patent segments the speed control function into two distinct levels: macro level speed adjustment and micro level speed control. The macro level is handled by the hydraulic coupling mechanism, while the micro level is achieved through pneumatic actuators that can make fine adjustments to the generator speed, thereby achieving high precision control.
Solution Approach 2:
The patent introduces a pneumatic control system working in conjunction with the hydraulic CVT. The pneumatic actuators provide precise micro-level speed control by adjusting the hydraulic coupling, complementing the macro-level control and enhancing overall control precision and flexibility.
3Productivity
If pneumatic energy storage is added for direct drive, then power generation during low wind conditions is enabled, but device complexity increases
Solution Approach 1:
The patent incorporates pneumatic energy storage tanks that pre-store compressed air energy. When wind conditions are insufficient, the stored pneumatic energy is released to drive the generator, enabling power generation without requiring complex backup systems. The energy is prepared in advance and activated only when needed.
Solution Approach 2:
The pneumatic system serves multiple functions: it provides micro-level speed control during normal operation, enables direct drive during low wind conditions, and can supplement power generation. This multi-functionality reduces the need for separate systems for each function, thereby limiting the increase in overall device complexity.
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 efficient micro-level speed adjustments and energy storage, enabling optimal power generation during varying wind conditions and minimizing load imbalances by providing a reactive balance electrical source.
Implementation Method 1
a hydraulic system having first hydraulic chamber linked to the turbine output shaft and a second hydraulic chamber linked to the electrical generator input shaft. The first and second hydraulic chambers are in hydraulic communication with each other
Implementation Method 2
The first pneumatic chamber is linked to the turbine output shaft for producing compressed air and storing it in at least one storage tank
Implementation Method 3
The second pneumatic chamber is linked to the electrical generator input shaft and the at least one storage tank for one or more of micro speed adjustment of the electrical generator input shaft, braking of the electrical generator input shaft, and direct drive of the electrical generator input shaft
Data Source
AI summary
A hydraulic continuous variable transmission is provided to connect a wind turbine and a generator. The hydraulic continuous variable transmission has a primary paddle wheel and a number of secondary paddle wheels for macro speed control. Also provided are pneumatic paddle wheels for micro speed control. A controller is included that measures AC electrical characterized output to load or line for speed control.