Rotating Electrical Machine Lead Wire Surge Suppression
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Solution Overview
Problem
Conventional methods for suppressing steep surge voltages in rotating electrical machines driven by inverter devices either increase the size or cost of the machine, as they require external filters or terminal box modifications.
Innovation Solution
Integrating an LC filter function into the lead wire of the rotating electrical machine by increasing its inductance and stray capacitance, which is achieved by placing the lead wire in a groove or hole within the stator core and covering it with an insulating member, allowing it to act as a filter without enlarging the machine's footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an external dV/dt suppression filter is provided in the input port of the electric motor, then the surge voltage is attenuated/absorbed, but the size of the whole rotating electrical machine system is increased and the cost is increased
Solution Approach 1:
The patent merges the filter function with the lead wire by forming an LC filter using the lead wire's own inductance and adding a capacitor, eliminating the need for separate external filters. This integration reduces the overall system size while maintaining surge suppression functionality.
Solution Approach 2:
The lead wire is given dual functionality: it serves both as the electrical connection conductor and as part of the filter system. By utilizing the lead wire's inherent inductance and adding a capacitor, the same component structure performs both current conduction and surge suppression.
2Object-affected harmful factors
If a conductive member is covered with an insulating member and passed through a laminated core in a terminal block to form an LC filter, then the surge is absorbed, but the terminal box of the rotating electrical machine is increased
Solution Approach 1:
The patent combines the filter components (inductance from lead wire and capacitor) directly within the lead wire structure itself, rather than housing them in a separate terminal box. This integration eliminates the need for additional terminal box volume.
Solution Approach 2:
The lead wire serves itself as the inductive element of the filter by utilizing its own physical properties (inductance), eliminating the need for separate inductors or complex terminal box structures. The capacitor is positioned to work with the lead wire's inherent characteristics.
3Object-affected harmful factors
If conventional external filters are used to suppress surge voltage, then the voltage attenuation is achieved, but the cost of the rotating electrical machine system is increased
Solution Approach 1:
The patent integrates the filter functionality into the existing lead wire structure, eliminating the need for separate external filter components. This reduces part count, assembly complexity, and overall system cost while maintaining surge suppression performance.
Solution Approach 2:
The lead wire's inherent electrical properties (inductance) are utilized as the filtering element, eliminating the need for additional expensive filter components. The capacitor is selected to work with the lead wire's natural characteristics, reducing overall system cost.
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 effectively suppresses steep surge voltages with a low-cost solution, reducing the shared voltage rate of the coils by up to 22% without increasing the machine's size, as demonstrated by the increased inductance and stray capacitance enhancing the LC filter function.
Implementation Method 1
an LC filter is formed by inductance and a stray capacitance of the conductive member
Implementation Method 2
an LC filter is formed by inductance and a stray capacitance of the conductive member
Data Source
Figure 1a~1b
Figure 2~3
Figure 4a~4b
AI summary
Provided is a rotating electrical machine that makes shared voltages of coils substantially uniform when a steep surge voltage is generated. In a rotating electrical machine 1 including: a rotor 8; a stator winding 3; a lead wire 7 connected to supply power to the stator winding 3; a stator core 2 around which the stator winding 3 is wound; and a casing 4 housing the stator core, the stator core 2 is ground, and the lead wire is placed to face an outer circumferential surface of the stator core via a dielectric 5 along a surface direction.