Multi-Pump Hydraulic Pressure Control Without Flow Interruption
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Solution Overview
Problem
Large wind turbines face challenges in maintaining hydraulic system pressure and flow due to the limitations of squirrel-cage induction motors, which result in interruptions when adding or removing motor-pump units, leading to undesirable dynamics and potential structural damage.
Innovation Solution
A hydraulic pump arrangement with multiple motor-pump units connected to a common confluence, featuring a controller that monitors motor speed and actuates bypass valves to manage pressure and flow, allowing units to be shut down or started without interrupting the system's pressure and flow, using feedback signals to adjust motor speeds and activate bypass valves as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single dump valve is used to relieve pressure at the confluence when starting motor-pump units, then the pump outlet pressure is relieved to allow motor startup, but the flow to the system is temporarily cut off causing undesirable dynamics and potential structural damage
Solution Approach 1:
The invention divides the single dump valve into multiple individual bypass valves, one for each motor-pump unit. This segmentation allows selective pressure relief at specific pump outlets while maintaining pressure and flow from other running pumps to the consumer, eliminating the flow interruption problem caused by a single centralized dump valve.
Solution Approach 2:
The bypass valve for each motor-pump unit is opened before starting the motor to preemptively relieve pressure at that specific outlet. This preliminary action prevents pressure buildup that would阻碍 motor startup while allowing other pumps to continue supplying the consumer without interruption.
2Power
If multiple motor-pump units are used to increase hydraulic system capacity, then the system can meet higher pressure and flow demands, but adding or removing units causes pressure and flow interruptions
Solution Approach 1:
Each motor-pump unit has its own dedicated bypass valve, enabling independent pressure management for each unit. This allows individual units to be started or stopped without affecting the pressure supply from other units to the consumer, maintaining system stability during capacity adjustments.
Solution Approach 2:
The system maintains continuous pressure and flow delivery to the consumer by allowing running pump units to compensate for units being started or stopped. The bypass valves enable smooth transitions without interrupting the overall hydraulic supply, ensuring continuous useful action.
3Ease of manufacture
If squirrel-cage induction motors are used in motor-pump units, then the system benefits from robust and simple motor construction, but the motors can only provide a fraction of nominal-speed torque at low speeds requiring low outlet pressure during startup
Solution Approach 1:
The bypass valve is opened before motor startup to preemptively relieve pressure at the pump outlet. This creates the low-pressure condition needed for squirrel-cage induction motor startup while maintaining the simplicity and robustness of the motor construction.
Solution Approach 2:
Individual bypass valves at each pump outlet allow localized pressure relief specifically at the starting pump without affecting pressure requirements at other pumps or the consumer, enabling simple motor construction to be used effectively.
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 solution ensures continuous pressure and flow to the consumer, preventing sudden losses or surges, thus avoiding structural loads that exceed design limits and reducing maintenance costs by smoothly managing the addition or removal of motor-pump units.
Implementation Method 1
a bypass valve configured to relieve pressure at the pump outlet
Implementation Method 2
a controller configured to receive a feedback signal from each motor-pump unit, to determine the speed of the motor-pump units from the corresponding feedback signals, and to actuate the bypass valve of a motor-pump unit on the basis of the motor speed of that motor-pump unit
Data Source
Figure 1
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AI summary
The invention describes a hydraulic pump arrangement (1) comprising a plurality of motor-pump units (MP1, ..., MPn) connected to a common confluence (10), wherein each motor-pump unit (MP1, ..., MPn) of the hydraulic pump arrangement (1) comprises a pump realised provide pressurized fluid at its outlet; a motor arranged to drive the pump; a bypass valve (V1, ..., Vn) configured to relieve pressure at the pump outlet; and wherein the hydraulic pump arrangement (1) further comprises a controller (11) configured to receive a feedback signal (FB1, ..., FBn) from each motor-pump unit (MP1, ..., MPn) and to actuate the bypass valve (V1, ..., Vn) of a motor-pump unit (MP1, ..., MPn) on the basis of the motor speed of that motor-pump unit (MP1, ..., MPn). The invention further describes a method of operating such a hydraulic pump arrangement (1), and a wind turbine (4) comprising a number of such hydraulic pump arrangements (1).