Variable Reluctance Resolver Slot Rotor Configuration
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Solution Overview
Problem
Existing variable reluctance resolvers face challenges in achieving high precision rotation angle detection with a limited number of stator slots, leading to increased size and cost, as well as electrical errors due to unbalanced phase and impedance in output coils.
Innovation Solution
A variable reluctance resolver design with an annular stator having stator slots equal to the product of an integer P of 2 or more and 4, and a rotor with convex portions equal to the product of an odd number m of 3 or more, featuring excitation coils and output coils wound in a balanced manner to minimize electrical errors and enhance detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of stator slots is increased to achieve high precision rotation angle detection, then detection accuracy is improved, but the size and cost of the resolver increase
Solution Approach 1:
The patent changes the fundamental parameter relationship between stator slots and rotor convex portions. Instead of the conventional N=4n relationship, it establishes N=m×P where m is an odd number and P is an integer of 2 or more. This parameter change enables high detection accuracy with fewer stator slots, directly resolving the contradiction between measurement precision and device size.
2Measurement precision
If the number of stator slots is increased to achieve high precision rotation angle detection, then detection accuracy is improved, but the cost of the resolver increases
Solution Approach 1:
By changing the slot configuration parameter from N=4n to N=m×P, the patent reduces the total number of stator slots required for high-precision detection. This parameter change directly reduces manufacturing complexity and cost while maintaining or improving detection accuracy.
3Measurement precision
If three coils are provided from the inner circumferential surface to the outer circumferential surface of the stator slots to increase nX with limited stator slots, then shaft-multiple angle number is increased, but the phase and impedance of output coils become unbalanced causing large electrical error
Solution Approach 1:
The patent changes the slot number parameter to N=m×P where m is odd, which fundamentally alters the magnetic circuit configuration. This parameter change enables balanced coil winding arrangements that maintain equal phase and impedance relationships, eliminating the electrical errors that occur with conventional multi-layer coil configurations.
Solution Approach 2:
By using an odd number m in the slot configuration formula N=m×P, the patent creates an asymmetric relationship between stator slots and rotor convex portions that is mathematically optimized for balanced three-phase output. This asymmetric parameter choice prevents the phase unbalance that occurs in conventional symmetric N=4n configurations when using multiple coil layers.
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 design allows for high-precision rotation angle detection with a reduced number of stator slots, improving detection accuracy and maintaining electrical balance, thus reducing the size and cost of the resolver.
Implementation Method 1
excitation coils which are provided in all the stator slots and generate a magnetic field by the application of a voltage
Implementation Method 2
The magnetic resistance in a magnetic path changes with the rotation of the resolver rotor. The electric signals output from the output winding change with the changes in the magnetic resistance
Data Source
AI summary
A VR resolver comprises a resolver stator and a resolver rotor. Teeth whose number is equal to the product of an integer P of 2 or more and 4 are arranged in an annular shape from the inner circumferential side to the inner side in the diameter direction of the resolver stator. In the resolver rotor, convex portions whose number is equal to the product of an odd number m of 3 or more and the integer P are radially projected. All the stator slots are provided with excitation coils which generate a magnetic field by the application of a voltage. Moreover, all the stator slots are provided with either a first coil or a second coil which outputs electric signals of different waveforms based on the magnetic field.