Variable-Speed Pump-Turbine Clusters for Wide-Range Efficiency
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Solution Overview
Problem
Existing hydraulic rotating machinery (HRM) systems operate inefficiently when the condition of service (COS) deviates significantly from the best efficiency point (BEP), leading to reduced efficiency, increased wear, and energy losses, particularly in applications requiring wide COS ranges such as green energy storage and recovery systems.
Innovation Solution
A cluster of variable speed HRMs interconnected by a plumbing system, controlled by an HRM controller, dynamically adjusts operating speeds and interconnections to maintain optimal efficiency across a wide range of conditions, using a process-dependent algorithm to select HRMs and configure flow paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed speed HRM is used, then the device complexity is reduced, but the hydraulic efficiency deteriorates when operating conditions deviate from the best efficiency point
Solution Approach 1:
The patent implements variable speed control for HRMs, allowing the rotational speed to be dynamically adjusted based on operating conditions. This enables the HRM to maintain optimal efficiency across a wide range of flow rates and pressures by continuously adapting its speed, rather than operating at a fixed speed point
Solution Approach 2:
The patent changes the operational parameters of the HRM by varying the rotational speed according to the actual operating conditions. The control system adjusts speed parameters in real-time to match the best efficiency point requirements, transforming the HRM from a static fixed-speed device to a dynamic variable-speed system
2Loss of energy
If the operating speed of HRM is varied to maintain efficiency over wide COS range, then the hydraulic efficiency is improved, but the device complexity increases
Solution Approach 1:
The patent employs a single HRM unit that can perform multiple functions by varying its operating speed. The same HRM can operate efficiently across different modes (pumping, turbine, hybrid) and different operating conditions, eliminating the need for multiple dedicated devices for different工况
Solution Approach 2:
The patent implements a control system that uses feedback from operating conditions (flow rate, pressure, power consumption) to automatically adjust the HRM speed. This closed-loop control maintains optimal efficiency without requiring complex mechanical adjustments, using electronic sensing and control to manage the variable speed operation
3Ease of operation
If throttle valves are used to control hydraulic output of fixed speed HRM, then the flow rate control is achieved, but the energy losses increase
Solution Approach 1:
The patent replaces the mechanical throttle valve control system with an electronic variable speed control system. Instead of using mechanical valves to restrict flow and dissipate energy, the system electronically controls the motor speed to match the desired flow rate, eliminating the energy-wasting throttling mechanism
Data Source
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AI summary
A "hydraulic rotating machinery" ("HRM") system provides optimal energy efficiency over a very wide conditions of service ("COS") range by configuring a plurality of variable speed HRMs in a "cluster." The HRMs are interconnected by one or more valves that can be actuated by a controller to configure and vary a flow path through which a process fluid flows from an inlet to an outlet. By actively selecting which of the HRMs are included in the flow path, the interconnections therebetween, and the operating speeds thereof, the controller ensures that the HRM cluster continues to operate at optimal efficiency as the COS fluctuates over a very wide range. The HRMs can be identical to each other, or can vary in design. The HRM system can be implemented for storage and retrieval of green energy. The controller can also monitor the health of the cluster and/or of the associated process.