PMSM Phase Switching via Rotor Magnetic Field Redirection
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Solution Overview
Problem
Existing permanent magnet synchronous motors face challenges in synchronously switching electrical phases with brushes and commutators, necessitating improved systems and methods for efficient phase synchronization.
Innovation Solution
A system employing an encoder with a tone wheel attached to the rotor, which redirects the magnetic field away from Hall effect sensors in a timed manner, using a magnetic permeable disk or ring with flux return lobes and teeth to alternately increase and decrease the magnetic field detected by the sensors, allowing for synchronized phase switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If brushes and commutators are used to switch electrical phases, then phase switching can be achieved, but the system complexity and maintenance requirements increase
Solution Approach 1:
The patent extracts and removes the brushes and commutators from the motor system, replacing them with a sensor-based detection system that reads positional information from a coded rotor surface, thereby eliminating the complex mechanical switching components while maintaining phase switching capability
Solution Approach 2:
The patent replaces the mechanical brushes and commutators system with an electromagnetic sensing system using sensors that detect magnetic field patterns on the rotor, substituting mechanical contact-based phase switching with non-contact electromagnetic detection and control
2Reliability
If brushes and commutators are used for phase switching, then synchronous switching can be achieved, but reliability decreases due to wear and contact issues
Solution Approach 1:
The patent replaces the wear-prone mechanical brushes and commutators with non-contact magnetic sensors that read positional information from the rotor, eliminating friction, wear, and contact degradation issues while maintaining reliable synchronous phase switching over extended service life
Solution Approach 2:
The rotor surface is coded with magnetic patterns that automatically provide positional information to the sensors, allowing the system to self-determine phase timing without external intervention or wear-prone components, thereby improving reliability and extending service life
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
The solution enables precise and efficient synchronous switching of electrical phases, matching the rotating magnetic field of the motor's rotor, and can be adapted for motors with multiple phases by adjusting the number of tone wheels and sensors, improving phase synchronization accuracy and efficiency.
Implementation Method 1
employing an encoder that includes a tone wheel affixed to a rotor such that the tone wheel redirects a magnetic field away from Hall effect sensors in a timed manner
Implementation Method 2
the tone wheel redirects a magnetic field away from Hall effect sensors in a timed manner
Data Source
AI summary
Systems and methods of synchronously switching electrical phases of a permanent magnet synchronous motor are provided. Some embodiments can include switching the phase of the motor by employing an encoder that includes a tone wheel affixed to a rotor such that the tone wheel redirects a magnetic field away from Hall effect sensors in a timed manner.