Rotating Electric Machine Coil Surge Withstand
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Solution Overview
Problem
Conventional rotating electric machines lack effective measures to withstand steep-fronted surge voltages from inverters, particularly at low-voltage operations, due to insulation limitations and challenges in controlling capacitance between turns, leading to potential insulation deterioration.
Innovation Solution
The design involves splitting coils into groups and connecting the starting and ending sections of winding magnet wires to create a capacitance element outside the slots, allowing surge voltages to be absorbed without relay through coil inductance, thereby increasing surge withstand voltage without enlarging insulating dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If insulation thickness is increased to withstand surge voltage, then turn-to-turn insulation reliability is improved, but machine dimensions must be enlarged
Solution Approach 1:
The coil is segmented into multiple coil groups (first coil group, second coil group, etc.) with different numbers of turns. This segmentation allows each group to have optimized insulation requirements, reducing the overall insulation thickness needed while maintaining surge voltage withstand capability through the distributed capacitance effect of multiple groups in series.
Solution Approach 2:
The invention changes the electrical parameters by creating unequal turn distributions among coil groups. The first coil group has fewer turns than the second coil group, which alters the voltage distribution and capacitance characteristics. This parameter change allows the system to withstand surge voltages without requiring increased insulation thickness, thus avoiding machine dimensional enlargement.
2Reliability
If capacitor is added to adjust distributed capacitance between turns, then surge voltage withstand is improved, but device complexity and space requirements increase
Solution Approach 1:
The invention makes the coil structure itself provide the capacitance adjustment function through its segmented design. The distributed capacitance between the multiple coil groups naturally serves the function of surge voltage mitigation, eliminating the need for external capacitors or additional components. The coil structure serves dual purposes: electromagnetic function and surge protection function.
Solution Approach 2:
The invention merges the surge protection function with the existing coil structure. By integrating the capacitance-adjusting function directly into the coil groups' arrangement and turn distribution, the system combines electromagnetic energy conversion and surge voltage mitigation into a single integrated structure, avoiding additional devices.
3Reliability
If insulation dimensions are increased to prevent insulation deterioration, then reliability against surge voltage is improved, but machine compactness is reduced
Solution Approach 1:
By dividing the coil into multiple coil groups with different turn counts, the voltage stress on each group's insulation is reduced. The segmentation creates a distributed capacitance effect that limits the maximum voltage any single insulation layer must withstand, allowing for thinner insulation while maintaining overall reliability and compactness.
Solution Approach 2:
Changing the turn distribution parameters among coil groups alters the voltage and capacitance characteristics. This parameter optimization allows the system to achieve adequate surge voltage withstand capability with reduced insulation dimensions, thereby maintaining machine compactness while improving reliability.
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 reduces turn-to-turn voltage and enhances surge withstand voltage, improving the reliability and safety of rotating electric machines against unpredictable voltage changes, such as those from inverter-driven systems, without increasing machine dimensions or requiring external capacitors.
Implementation Method 1
the starting sections and ending sections of winding of the magnet wires in the two coil groups are connected at respective outgoing wire ends to one another, outside the slots... capacitance between a turn and a core, and the capacitance between turns
Data Source
AI summary
A rotating electric machine includes a stator core of a cylindrical shape, a rotor core coaxially rotating inside the stator core, and a plurality of coils each formed by winding magnet wires using a slot formed axially in either the stator core or the rotor core, or both: it is preferable that each of the coils be split into a plurality of coil groups, that starting sections of winding of the magnet wires in one of the coil groups be wound adjacently to ending sections of winding of the magnet wires in another of the coil groups, and that the starting sections and ending sections of winding of the magnet wires in the two coil groups be connected at respective outgoing wire ends to one another, outside the slots.