Centrifugal Pump Startup Energy Sensing for Load Torque Detection
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Solution Overview
Problem
Centrifugal pumps face challenges in determining load torque during startup phases without sensors, especially at low speeds, due to the absence of torque sensors and rotor position sensors, which hinders accurate evaluation of operating information and system performance.
Innovation Solution
The method involves determining the starting energy consumed by the electric motor during startup by integrating motor input power, using existing current and voltage sensors, to indirectly evaluate load torque and infer operating information such as dry running, hydraulic resistance, and pump aging, without the need for additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If torque sensors and rotor position sensors are installed to accurately measure load torque during startup, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The pump drive system uses its own existing current and voltage sensors to measure and calculate load torque during startup, without requiring additional torque sensors or rotor position sensors. The system serves itself by utilizing already-available measurement capabilities to determine operating information.
Solution Approach 2:
The patent replaces direct mechanical measurement (torque sensors) with an indirect electrical measurement approach. By measuring electrical quantities (current, voltage, power) and calculating mechanical torque through mathematical relationships, the system avoids mechanical sensors while achieving the same measurement goal.
2Measurement precision
If field-oriented control is used at low speeds to obtain q-current for torque assessment, then measurement precision is improved, but ease of operation deteriorates due to complex sensor requirements
Solution Approach 1:
The patent extracts the essential measurement information (load torque) from the complex field-oriented control system by using only the q-current component that can be obtained from existing sensors. It separates the necessary measurement function from the unnecessary sensor requirements, simplifying the operational process.
Solution Approach 2:
The patent introduces power consumption as an intermediary quantity that connects electrical measurements to mechanical torque assessment. By using power (P = U × I) as a mediator, the system can determine torque information without directly measuring it or requiring complex sensor systems.
3Reliability
If startup phase is extended to gather more operating data, then reliability is improved, but loss of time increases
Solution Approach 1:
The patent performs operating information determination during the necessary startup phase itself, rather than requiring an extended measurement period. By calculating torque and detecting operating conditions (dry running, hydraulic resistance, aging) during the normal startup acceleration, the system achieves reliable measurements without extending startup time.
Solution Approach 2:
The patent skips the traditional approach of waiting for steady-state operation to gather measurement data. Instead, it rushes through the startup phase by continuously monitoring and calculating operating information in real-time during acceleration, obtaining reliable data before the pump reaches its intended operating speed.
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 quick detection of dry running, hydraulic resistance, and pump aging, enabling immediate adjustments and maintenance, even before the pump reaches its intended operating speed, thereby improving operational efficiency and reducing maintenance costs.
Implementation Method 1
starting energy which has been consumed by an electric motor (2) of the centrifugal pump during a start-up phase
Implementation Method 2
an electric centrifugal pump (1) in a hydraulic system
Data Source
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AI summary
The invention relates to a method for determining at least one operating parameter of an electric centrifugal pump in a hydraulic system, or of this hydraulic system, in particular a heating or cooling system, with at least one consumer to which the centrifugal pump delivers a fluid during normal operation, wherein the centrifugal pump initially starts up from zero speed in a controlled start-up phase (A) and subsequently transitions to speed-controlled operation (B). The starting energy (W) consumed by the electric motor of the centrifugal pump during the start-up phase (A) is determined by integrating the electrical power consumption of the electric motor, and the operating parameter is derived from this.