Brushless DC Machine With Insulating Winding Carrier
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Solution Overview
Problem
Conventional DC machines suffer from inefficiencies due to magnetic reversal and eddy current losses, and complex power electronics are required to operate them effectively as both motors and generators, especially in applications like electromobility where energy efficiency and versatility are crucial.
Innovation Solution
A DC machine design featuring a stator and rotor with a winding support made of ferromagnetically inactive material, utilizing a double-row arrangement of radially polarized permanent magnet elements to generate Lorentz forces that compensate radial magnetic forces and create a resultant tangential force for acceleration, allowing operation as both a motor and generator without electronic aids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If ferromagnetic material is used to increase electromagnetic field strength, then the electromagnetic coupling between stator and rotor is improved, but magnetic reversal and eddy current losses occur which reduce efficiency
Solution Approach 1:
The invention extracts and removes the ferromagnetic material from the winding carrier, replacing it with a non-magnetic, electrically insulating material. This eliminates the source of magnetic reversal and eddy current losses while maintaining the necessary electromagnetic field strength through alternative means - specifically through the strategic arrangement of permanent magnet elements in two rows that create a controlled magnetic field without requiring ferromagnetic saturation.
Solution Approach 2:
The invention changes the magnetic field generation approach by using permanently magnetized elements arranged in two rows with opposite polarizations, rather than relying on ferromagnetic material saturation. This parameter change in the magnetic field generation mechanism allows maintaining field strength while eliminating the harmful iron losses associated with alternating magnetic field reversal in ferromagnetic materials.
2Adaptability or versatility
If conventional DC machine design with sliding contacts and commutators is used, then the machine can operate as motor or generator, but wear occurs due to brush sparking which reduces reliability
Solution Approach 1:
The invention replaces the mechanical sliding contact and commutator system with a brushless design using permanently magnetized elements and a winding carrier with insulating material. The magnetic field interaction between the permanent magnets and the windings enables both motor and generator operation without mechanical contact, thereby eliminating brush sparking and wear while maintaining operational versatility.
3Use of energy by moving object
If complex power electronics are used to operate DC machine efficiently, then energy efficiency is improved, but device complexity increases
Solution Approach 1:
The invention enables the DC machine to achieve high energy efficiency through its self-service design - the permanently magnetized elements and insulating winding carrier create a system that inherently minimizes losses without requiring complex power electronics for loss compensation. The dual-row permanent magnet arrangement automatically optimizes the magnetic field distribution, and the insulating material automatically prevents eddy currents, eliminating the need for complex control systems.
4Strength
If ferromagnetic winding carrier is used to support windings, then mechanical strength is improved, but magnetic saturation occurs which reduces efficiency
Solution Approach 1:
The invention extracts the ferromagnetic material from the winding carrier structure and replaces it with a non-magnetic, electrically insulating material. This removal eliminates magnetic saturation in the winding carrier while the mechanical strength requirement is satisfied through the structural design of the insulating carrier itself, which is configured to mechanically support the windings and the two rows of permanent magnet elements.
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 enhances efficiency by minimizing magnetic saturation and iron losses, enabling smooth operation and adaptable torque control without the need for complex power electronics, while maintaining high electromechanical efficiency and reducing manufacturing costs.
Implementation Method 1
A movement of the rotor thus always leads to the coil elements being moved relative to the permanent magnet elements... the components of the Lorentz forces acting on the coil elements in the radial direction... the magnetic forces acting in the tangential direction add up, so that as a result a resultant force acts in the tangential direction on the coil elements
Implementation Method 2
the components of the Lorentz forces acting on the coil elements in the radial direction, which are also referred to as magnetic forces, largely compensate each other. On the other hand, the magnetic forces acting in the tangential direction add up
Data Source
Figure 1
Figure 2
Figure 2a~3
AI summary
The invention relates to a DC current machine comprising a rotor (3) that can rotate about an axis of rotation (4) and a stator (2) arranged coaxially relative to the rotor (3). In addition, the DC current machine comprises a cylindrical winding carrier (15) arranged centred relative to the axis of rotation (4), consisting of an electrically insulating and ferromagnetically inactive material, and having at least one first winding (16, 56a) of a first electrical conductor. The DC current machine also comprises a first group of permanent magnet elements (9) and a second group of permanent magnet elements (10), which are polarised in the radial direction in relation to the axis of rotation (4). The permanent magnet elements (9) of the first group form a first ring centred around the axis of rotation (4) and within the winding carrier. The permanent magnet elements (10) of the second group form a second ring centred around the axis of rotation (4) and outside the winding carrier.