Slim-Type Stator Using Multilayer PCB for Sensorless Single-Phase Motor
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Solution Overview
Problem
Conventional single-phase motors require expensive Hall sensors for rotor position detection, leading to increased costs and complexity, and struggle to achieve a slim-type stator structure with effective torque generation and reliable connections, while also facing challenges in cooling fan applications due to heat generation during wireless charging.
Innovation Solution
A slim-type stator using a multilayer printed circuit board (PCB) with a coil pattern and sensing coil pattern integrated on the surface layer, where the sensing coil is positioned to avoid magnetic pole interfaces, and a dead point prevention yoke function is implemented using bridges corresponding to the number of rotor magnetic poles, allowing for sensorless driving without additional components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Hall sensor is used for rotor position detection, then the rotor position can be detected, but the cost increases and the device complexity increases
Solution Approach 1:
The patent extracts the rotor position detection function from a separate Hall sensor component and integrates it into the stator coil winding structure itself. The sensing coil is wound together with the main stator coil, eliminating the need for an external Hall sensor while maintaining detection capability.
Solution Approach 2:
The patent merges the sensing coil and stator coil into a single integrated winding structure. Both coils are wound simultaneously on the same bobbin, sharing the same magnetic path and physical space, thereby reducing component count and device complexity while achieving sensorless operation.
2Device complexity
If a single-phase motor with a single coil is used, then the cost burden is reduced, but the rotor position detection becomes difficult without a Hall sensor
Solution Approach 1:
The patent uses the back electromotive force (EMF) generated in the sensing coil as an intermediary signal to infer rotor position. Instead of directly detecting magnetic poles with a Hall sensor, the sensing coil captures voltage signals that vary with rotor position, which are then processed to determine the rotor angle for commutation.
Solution Approach 2:
The patent replaces the mechanical/electronic Hall sensor system with an electromagnetic sensing approach. The sensing coil detects rotor position through electromagnetic induction (back EMF) rather than direct magnetic field sensing, enabling sensorless control in a single-phase motor configuration.
3Measurement precision
If a double winding type stator is used for sensorless driving, then the rotor position can be detected, but the structure becomes complicated and the stator cannot be made slim
Solution Approach 1:
The patent combines the sensing coil and stator coil into a single integrated winding structure wound on the same bobbin. This merger eliminates the need for separate sensing coil windings and reduces the overall stator structure complexity while maintaining the ability to detect rotor position through back EMF.
Solution Approach 2:
The integrated coil structure serves multiple functions simultaneously: it acts as both the main stator coil for torque generation and the sensing coil for rotor position detection. This multi-functionality eliminates the need for separate dedicated sensing windings, achieving sensorless operation with a simplified structure.
4Force
If a core type stator is used, then the torque generation is effective, but the stator height cannot be reduced
Solution Approach 1:
The patent replaces the traditional core type stator structure with a thin-film PCB-based stator coil structure. The coil pattern is directly formed on multiple layers of a thin PCB, eliminating the need for a bulky magnetic core while maintaining effective torque generation through optimized winding patterns and magnetic field distribution.
Solution Approach 2:
The patent changes the fundamental structural parameters of the stator from a core-type construction with significant height to a PCB-based planar structure. By transforming the coil geometry and utilizing multi-layer PCB technology, the stator achieves effective torque generation with dramatically reduced height and weight.
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 enables cost-effective, simple sensorless driving with enhanced torque generation and a slim-type motor structure, improving reliability and productivity, and effectively addresses heat management in cooling fan applications by integrating a dead point prevention yoke function without separate components.
Implementation Method 1
a back electromotive force (a back EMF) generated from the sensing coil at the time of rotor rotation is detected
Implementation Method 2
a coil pattern patterned on respective PCB layers of a multilayer PCB... to generate a rotational force applied to an opposite rotor
Data Source
AI summary
Provided are a slim-type stator using a multilayer printed circuit board (PCB) in which a coil pattern is patterned on an uppermost PCB layer and a sensing coil pattern for detecting a rotor rotation position is integrally formed in a margin of the uppermost PCB layer, to thereby realize sensorless driving simply, and a sensorless single-phase motor using the slim-type stator, and a cooling fan using the sensorless single-phase motor. The slim-type stator includes: a multilayer PCB; a coil pattern patterned on respective PCB layers of the multilayer PCB and connected through throughholes; and a sensing coil pattern formed on an uppermost PCB layer to detect a rotor rotation position, wherein the sensing coil pattern is positioned and set at a position deviated from a magnetic pole interface of a rotor that is positioned and set by a dead point prevention yoke when the rotor is in an initial state.