Underwater Turbine Posture Control via Variable Pitch Torque
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Solution Overview
Problem
Existing underwater floating-type ocean current power generation devices have complex structures and control systems for posture control, particularly in the roll direction, which complicates reliable posture management.
Innovation Solution
The implementation of a posture controller that adjusts the torque generated by the turbines to control the roll direction posture, using variable pitch turbine blades and sensors like depth meters or acoustic Doppler current profilers to maintain horizontal alignment and prevent deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pair of power generation units are tethered to the seabed via a buoyancy-imparting supporting strut and three tether cables with length control, then the depth and posture of the power generation units are controlled, but the structure and control system become complex
Solution Approach 1:
The invention extracts the posture control function from the complex tether cable length control system and transfers it to the turbines themselves. By controlling the torque generation of individual turbines, the roll direction posture is controlled directly at the source, eliminating the need for complex tether cable length adjustment mechanisms and their associated control systems.
Solution Approach 2:
The turbines serve dual functions: power generation and posture control. By controlling the torque that each turbine generates, the system uses the turbines' own operational characteristics to control the device's roll posture, rather than requiring separate dedicated posture control mechanisms. This self-service approach simplifies the overall system.
2Productivity
If variable pitch turbine blades are used to adjust flow resistance and output, then power generation performance is optimized, but the control system complexity increases
Solution Approach 1:
The variable pitch turbine blades are designed to serve multiple functions: optimizing power generation output and controlling device posture. By adjusting the pitch of specific turbine blades, the system simultaneously controls both the power generation characteristics and the roll direction posture, eliminating the need for separate control systems for these functions.
Solution Approach 2:
The invention changes the operational parameters of the turbine blades (pitch angle) to achieve dual objectives. By varying the pitch of individual blades, the system optimizes power generation while simultaneously controlling the torque distribution among turbines, thereby managing posture. This parameter-based control integrates multiple functions into a single control mechanism.
3Reliability
If a complex tether cable length control unit is installed on the buoyancy-imparting strut, then depth and posture control is achieved, but the device structure becomes more complex
Solution Approach 1:
The invention removes the complex tether cable length control unit from the buoyancy-imparting strut structure. Instead of controlling posture through tether cable length adjustment, the control function is extracted and transferred to the turbine torque control system, significantly simplifying the device structure while maintaining posture control capability.
Solution Approach 2:
The invention replaces the mechanical tether cable length control system with a torque-based control system. Rather than mechanically adjusting tether cable lengths to control posture, the system uses torque generation control of the turbines, which can be achieved through electrical or hydraulic actuation of variable pitch blades, resulting in a simpler overall mechanical structure.
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 approach allows for reliable and simple control of the roll direction posture of the device main body, eliminating the need for complex structures and control systems, ensuring stable operation without significant structural or operational complexity.
Implementation Method 1
ocean current power generation device that generates power using seawater flows such as ocean currents (i.e., tidal currents)
Implementation Method 2
tethered to the seabed via a buoyancy-imparting supporting strut that is used for depth control
Data Source
AI summary
This underwater device is twin-motor underwater floating-type power generation device that is provided with: a device main body that is equipped with a pair of pods that have a turbine, and with a connecting beam that connects these pods together in parallel with each other; a sinker; and tether cables that tether the device main body to the seabed via this sinker. The respective turbines of the pods are each provided with variable pitch turbine blades. This device is also provided with a depth meter that detects deviation in posture in the roll direction that is generated in the pair of pods, and a posture controller that controls the pitch of the variable pitch turbine blades of the respective turbines so as to nullify any deviation in posture in the roll direction that has been generated in the pair of pods and has been detected by the depth meter.