Electric Motor Sensor Arrangement for Noise Reduction
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Solution Overview
Problem
Conventional three-phase synchronous motors are prone to malfunction due to electromagnetic noise interference between the control circuit and magnetic sensors, leading to inaccurate rotor control.
Innovation Solution
The magnetic sensors and guide members are arranged within a reduced angular range of 60 degrees, allowing for shorter sensor wires and reduced electromagnetic noise interference, enabling precise rotor speed control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the three magnetic sensors are arranged within a smaller region to shorten wire lengths, then electromagnetic noise interference is reduced, but the arrangement space for sensors and guide members becomes more constrained
Solution Approach 1:
The patent applies dimensional change by transitioning from a planar arrangement to a three-dimensional spatial arrangement. The guide members are positioned at different radial distances from the rotor axis (first radial distance vs. second radial distance), creating a multi-layered configuration that reduces the angular spread of sensors while maintaining adequate spacing. This 3D arrangement allows sensors to be clustered within a smaller angular range (60 degrees) without compromising wire length or increasing electromagnetic interference.
2Area of stationary object
If all three guide members are arranged at the same radial position, then the arrangement region is minimized, but measurement accuracy may be compromised due to insufficient spatial distribution
Solution Approach 1:
The patent applies local quality by assigning different radial positions to different guide members based on their functional requirements. Guide members at the first radial distance are optimized for one set of measurements, while guide members at the second radial distance serve another measurement purpose. This differentiated spatial arrangement ensures that each sensor-guild member pair operates in an optimal local field environment, maintaining measurement precision while compacting the overall arrangement region to 60 degrees angular range.
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 configuration enhances the accuracy of rotor speed control and reduces the risk of malfunction by minimizing electromagnetic noise interference, allowing for more compact motor designs.
Implementation Method 1
Between a plurality of permanent magnets and the three magnetic sensors, there are provided three magnetic guide members that guide magnetic flux, which emanates from the plurality of magnetic poles of the rotor, respectively to the three magnetic sensors
Implementation Method 2
the inverter circuit outputs three-phase alternating current to the stator coil, thereby causing the stator coil to create a rotating magnetic field
Implementation Method 3
each of the three magnetic sensors detects the magnetic flux guided by a corresponding one of the three magnetic guide members
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A control circuit 63 controls, based on detection values of Hall-effect sensors 61a, 61b and 61c, an inverter circuit 62 to activate a rotor 50. After the activation of the rotor 50, the control circuit 63 controls the rotational speed of the rotor 50 based on the detection value of the Hall-effect sensor 61a. A sensor pin 81 is arranged in a slot 48u between a forward-wound portion 46 and a reverse-wound portion 47 of a U-phase winding 49a. A sensor pin 83 is arranged in a slot 48v between a forward-wound portion 46 and a reverse-wound portion 47 of a V-phase winding 49b. A sensor pin 82 is located on one side in an axial direction with respect to the reverse-wound portion 47 of the U-phase winding 49a. The sensor pins 81 and 83 are located respectively at two first positions.