Temperature prediction device, compressor with magnetic bearing mounted thereon, temperature prediction method and program
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Compressors with magnetic bearings face the risk of defects due to excess current flowing through their electromagnetic coils, necessitating a method to easily determine if excessive current is present.
Innovation Solution
A temperature prediction device that specifies the voltage applied to the electromagnetic coil based on distance, detects the current flowing through it, and estimates the coil's temperature using a relational expression between voltage, current, and temperature, allowing for the identification of excessive current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is used to detect the temperature of the rotary shaft surface, then the temperature can be measured, but it is difficult to determine whether excess current is flowing to the electromagnetic coil
Solution Approach 1:
The patent uses temperature as an intermediary parameter to indirectly detect excess current. Instead of directly measuring current, the system measures the coil temperature which reflects the power dissipation (I²R heating). When excess current flows, the coil temperature increases, providing an indirect but effective means of detecting abnormal current conditions without requiring direct current sensing circuitry.
Solution Approach 2:
The patent replaces direct electrical measurement (current sensing) with thermal measurement (temperature sensing). By substituting the electrical detection method with a thermal detection method, the system can infer current status through temperature rise, simplifying the detection mechanism while providing continuous monitoring capability.
2Reliability
If direct current detection methods are used, then excess current can be detected, but the system becomes more complex
Solution Approach 1:
The patent employs temperature as an intermediary variable that naturally reflects the state of current flow through Joule heating. This approach avoids the need for complex current sensing circuits, isolation amplifiers, and signal processing hardware, thereby reducing system complexity while maintaining reliable detection of excess current conditions.
Solution Approach 2:
The electromagnetic coil itself serves as the sensing element through its inherent resistive heating property. The coil's temperature rise due to I²R heating automatically provides the detection signal, eliminating the need for separate sensing components. The system leverages the physical property of the coil rather than adding external detection hardware.
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
Enables easy determination of excessive current flow, preventing defects and ensuring safe operation of compressors with magnetic bearings by accurately estimating coil temperatures.
Implementation Method 1
a rotary shaft is controlled such that it does not come into contact with a bearing by using a suction force due to the magnetism generated by applying a current to an electromagnetic coil
Implementation Method 2
when an excess current flows to an electromagnetic coil of a compressor with a magnetic bearing mounted thereon, there is a likelihood that a defect will occur in the electromagnetic coil
Data Source
AI summary
A temperature prediction device includes an application voltage specifying unit which specifics a voltage value applied to an electromagnetic coil based on a distance from a distance detection unit provided in the electromagnetic coil to an output shaft, a coil current detection unit which detects a current value flowing when a voltage is applied to the electromagnetic coil on the basis of the voltage value specified by the application voltage specifying unit, and a coil temperature estimation unit which estimates a temperature of the electromagnetic coil on the basis of the voltage value specified by the application voltage specifying unit, the current value detected by the coil current detection unit, and a relational expression between the voltage value applied to the electromagnetic coil, the current value flowing when a voltage is applied to the electromagnet coil on the basis of the voltage value applied to the electromagnetic coil, and the temperature of the electromagnetic coil.