Permanent Magnet Rotor Flux Control for Speed-Torque Switching
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Solution Overview
Problem
In rotating electric machines with a rotor having pairs of magnet housing holes, magnetic flux leaks to the bridge portion between holes, reducing the magnetic flux between the rotor and stator, leading to lower torque and output, and increased rotation speed, necessitating a method to adjust the leaked magnetic flux.
Innovation Solution
Incorporating a field yoke with a field coil that generates field magnetic flux to saturate the bridge portion, controlling the leakage of magnetic flux from permanent magnets, and adjusting the energization of the field coil to manage magnetic flux distribution between rotation speed and output modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If magnetic flux leaks to the bridge portion between magnet housing holes, then rotation speed can be increased due to reduced back electromotive voltage, but torque is reduced and output cannot be increased
Solution Approach 1:
The patent applies parameter changes by controlling the magnetic saturation state of the bridge portion through field coil energization. By adjusting the excitation current to the field coil, the magnetic permeability of the bridge portion can be dynamically changed between saturated and non-saturated states, thereby controlling the amount of magnetic flux leakage and achieving different operating modes for speed and torque optimization
Solution Approach 2:
The patent implements dynamics by making the magnetic circuit characteristics adjustable through field coil energization. The system can dynamically switch between two operational states: when the field coil is energized, the bridge portion becomes saturated and prevents flux leakage for high torque mode; when the field coil is not energized, the bridge portion allows flux leakage for high speed mode. This dynamic control enables the motor to adapt to different operating requirements
2Power
If field magnetic flux saturates the bridge portion to prevent magnet magnetic flux leakage, then output is increased by efficient magnetic flux usage, but back electromotive voltage increases and rotation speed decreases
Solution Approach 1:
The patent applies parameter changes by controlling the magnetic saturation state of the bridge portion through field coil energization. By adjusting the excitation current to the field coil, the magnetic permeability of the bridge portion can be dynamically changed between saturated and non-saturated states, thereby controlling the amount of magnetic flux leakage and achieving different operating modes for speed and torque optimization
Solution Approach 2:
The patent implements dynamics by making the magnetic circuit characteristics adjustable through field coil energization. The system can dynamically switch between two operational states: when the field coil is energized, the bridge portion becomes saturated and prevents flux leakage for high torque mode; when the field coil is not energized, the bridge portion allows flux leakage for high speed mode. This dynamic control enables the motor to adapt to different operating requirements
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 effectively increases output by optimizing magnetic flux usage, reduces back electromotive voltage for higher rotation speeds, and adjusts magnetic flux leakage to enhance torque and efficiency.
Implementation Method 1
a field coil that is provided in the field yoke and that generates field magnetic flux when energized
Implementation Method 2
a plurality of pairs of magnet housing holes is arranged in an outer periphery of a rotor core... each of the pairs of magnet housing holes respectively housing permanent magnets
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A rotating electric machine (1) includes: a rotor (3) including an annular rotor core (31) in which a plurality of pairs of magnet housing holes (33) is arranged in a circumferential direction (D3) in an outer periphery, each pair of magnet housing holes (33) respectively housing permanent magnets (32) and being arranged in such a manner as to be opened in a V-shape toward an outer side in a radial direction (D2); a stator (4) including an annular stator core (41) and a stator coil (42); and a field yoke (5A, 5B) in which a field coil (6A, 6B) that generates field magnetic flux when being energized is provided, wherein an end surface in an axial direction (D1) at one end in the radial direction (D2) of the field yoke (5A, 5B)and an end surface in the axial direction (D1) of a bridge portion (35) of the rotor core (31) face each other in the axial direction (D1), and an end surface in the axial direction (D1) at another end in the radial direction (D2) of the field yoke (5A, 5B), and an end surface in the axial direction (D1) of the rotor core (31) or an end surface in the axial direction (D1) of the stator core (41) face each other in the axial direction (D1).