Rotary Electrical Machine With Time-Invariant Fields to Eliminate Core Loss
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Solution Overview
Problem
Existing rotary electrical motors and generators suffer from electrical and volumetric inefficiencies due to core loss caused by time-varying magnetic fields, leading to waste heat and low power-densities, especially at high rotational speeds.
Innovation Solution
A rotary electrical machine utilizing time-invariant magnetic fields, comprising a core assembly with magnet assemblies defining an air gap and an armature assembly with conductors positioned within the air gap, where the armature and core can be mounted to rotating or stationary elements, allowing for efficient torque generation and power conversion without core loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If time-varying magnetic fields are used in existing rotary electrical motors and generators, then torque and rotational mechanical power are generated, but core loss occurs leading to waste heat and reduced efficiency
Solution Approach 1:
The patent inverts the conventional approach by using time-invariant (static) magnetic fields instead of time-varying magnetic fields. In conventional motors, time-varying fields are used to generate torque, but this causes core loss. The present application uses static fields from permanent magnets or electro-magnets combined with time-varying current in conductors to generate torque via the Lorentz force, eliminating core loss while maintaining power generation capability
Solution Approach 2:
The patent changes the temporal parameter of the magnetic field from time-varying to time-invariant. By using static magnetic fields with constant magnitude and direction (or constant radial/axial orientation), the patent eliminates the hysteresis and eddy-current losses that occur with time-varying fields, while still achieving torque generation through the interaction with time-varying current in the conductors
2Power
If time-varying magnetic fields are used to generate torque, then rotational power is produced, but waste heat increases especially at high rotational speeds
Solution Approach 1:
The patent converts the harmful effect of core loss into a benefit by eliminating it entirely. By using time-invariant magnetic fields, the patent removes the source of core loss (hysteresis and eddy-current heating) while maintaining the ability to generate rotational power through the Lorentz force interaction between static magnetic fields and time-varying current, thereby reducing waste heat especially at high rotational speeds
3Power
If conventional motor assemblies are used, then electrical power conversion is achieved, but volumetric efficiency is reduced due to large volumes required for conductors, poles, and coolant passages
Solution Approach 1:
The patent extracts and eliminates the need for coolant passages and associated cooling systems from conventional motor assemblies. By using time-invariant magnetic fields, core loss is eliminated, removing the primary heat generation source that necessitates coolant passages. This reduces the volumetric requirements of the motor while maintaining power conversion capability
Solution Approach 2:
The patent merges the functions of magnetic field generation and torque production more efficiently by using permanent magnets or electro-magnets to create time-invariant fields that directly interact with conductors. This integration eliminates the need for separate cooling systems and reduces the overall volume required for the motor assembly while achieving the same or better power conversion
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 achieves higher power-densities and efficiencies by eliminating core loss, enabling operation at high speeds with reduced waste heat and increased volumetric efficiency, making it more power-dense and cost-effective compared to current-art motors and generators.
Implementation Method 1
The time-varying current flowing through the conductor in the time-invariant magnetic field produces a time-varying Lorentz force on the conductor
Data Source
AI summary
A rotary electrical machine comprises: a mechanical motor/generator assembly, and optional electronics. The mechanical motor/generator assembly comprises: a core assembly, and an armature assembly. The core assembly comprises two magnet assemblies, which are positioned to define an air gap therebetween and produce time invariant magnetic fields in the air gap. The armature assembly comprises: an armature, and one or more conductors that are mounted to the armature and positioned in the air gap. Either the core assembly or the armature assembly may be mounted to a rotating element, while the other is mounted to a stationary element. During operation as a motor, electrical current flows in alternating directions in the one or more conductors, to produce torque on the armature and rotating element. During operation as a generator, electrical current is produced in the one or more conductors when torque is applied to the rotating element and the armature.