Multi-Phase Motor with Opposite Stator Rotor Currents
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Solution Overview
Problem
Existing motor technologies face challenges in achieving high peak torque and power factor efficiency, especially in electric vehicles and industrial applications, where torque requirements vary significantly with rotation speed, leading to increased motor size, weight, and production costs due to armature reaction and field magnetic flux distortions.
Innovation Solution
The development of a motor configuration with multiple-phase stator windings and rotor windings arranged in a specific pattern, where stator and rotor currents are oppositely directed to minimize armature reaction, allowing for concentrated magnetic flux at the airgap and controlled field weakening, enabling higher torque output and improved power factor across varying speed ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the motor operates in area A to generate larger torque in lower rotation speeds, then the torque output is improved, but the power factor reduces and motor current increases
Solution Approach 1:
The patent changes the control parameters by independently controlling stator and rotor currents with opposite directions, adjusting the current phase difference to minimize armature reaction and optimize power factor while maintaining high torque output in area A
2Force
If the motor operates in area A to generate larger torque, then the torque output is improved, but motor copper loss increases
Solution Approach 1:
The patent optimizes current parameters by controlling stator and rotor currents with opposite directions and adjusting phase differences, which minimizes armature reaction and reduces copper loss while maintaining high torque output capability
3Speed
If the motor operates in range B for higher-speed rotation, then the rotation speed is improved, but the motor voltage becomes excessively larger
Solution Approach 1:
The patent changes operating parameters by controlling stator and rotor currents with opposite directions and adjusting phase differences, which enables field weakening control to reduce motor voltage while maintaining high-speed rotation capability in range B
4Speed
If the motor operates in range B for higher-speed rotation, then the rotation speed is improved, but the driving inverter load increases and power factor reduces
Solution Approach 1:
The patent optimizes current phase parameters by controlling stator and rotor currents with opposite directions, which improves power factor during high-speed operation in range B and reduces the load on the driving inverter
5Force
If field magnetic fluxes are increased for larger torque, then the torque output is improved, but the motor size increases
Solution Approach 1:
The patent changes the control approach by independently controlling stator and rotor currents with opposite directions, which optimizes field magnetic flux utilization and enables high torque output with reduced motor size through improved power density
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 results in higher torque density, reduced motor size, weight, and production costs, while maintaining efficient power factor control, especially during high-speed rotations, by eliminating armature reaction and optimizing field magnetic flux distribution.
Implementation Method 1
a stator winding SA arranged in a stator (11), the stator winding being arranged in a circumferential periphery of the stator, the circumferential periphery being opposed to a rotor side
Implementation Method 2
a rotor winding R1 arranged in a rotor (12), the rotor winding being arranged in a circumferential direction of the rotor at approximately even pitches in a portion close to a circumferential periphery of rotor magnetic poles RP
Implementation Method 3
wherein a flowing direction of a current SIG to the stator winding and a flowing direction of a current RIG to the rotor winding are relatively, in part or all of the current, opposite to each other
Implementation Method 4
allowing for concentrated magnetic flux at the airgap
Data Source
AI summary
A motor has stator windings arranged on a circumference of a stator, a rotor with rotor magnetic poles provided by N- and S-poles, and rotor windings arranged in a circumferential direction of the rotor magnetic poles. Multiple-phase currents are supplied to the stator windings. A current is supplied to rotor windings. The multiple-phase currents include torque current components, which are arranged to be opposite in directions to torque current components of the current. By this mutually opposite-directional current arrangement, a magnetomotive force based on a sum of both torque current components becomes a local minimum. It is possible to reduce influence of the torque current components on the field magnetic fluxes of the motor. In the motor, circumferential magnetic flux components can be collected to an airgap and a portion therearound, so that a larger amount of torque can be obtained, and constant output control can be performed more easily.