Polyphase Motor with Straight Stator Teeth and Hybrid Rotor
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Solution Overview
Problem
Current polyphase motors with flared stator poles face limitations in torque production, winding volume, assembly complexity, and magnetic saturation, leading to reduced efficiency and increased operating losses.
Innovation Solution
A polyphase electric motor design featuring a stator with straight or trapezoidal teeth and a rotor with alternation of magnetized and salient poles, allowing for improved magnetic flux and reduced variable reluctance torque, enabling higher torque density and smoother operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If flared stator poles are used, then magnetic flux is increased and residual torque is reduced, but winding volume is limited and manufacturing complexity increases
Solution Approach 1:
The invention changes the geometric parameters of the stator poles from flared to straight cylindrical shape, maintaining constant cross-sectional area along the radial direction. This parameter change allows increased winding volume while managing magnetic flux through optimized pole dimensions and arrangement.
2Power
If flared stator poles are used, then magnetic flux is increased, but magnetic saturation increases and operating losses increase
Solution Approach 1:
The straight pole geometry with constant cross-section allows optimization of magnetic path length and flux distribution, reducing magnetic saturation effects and associated losses while maintaining effective magnetic coupling.
3Object-generated harmful factors
If flared stator poles are used, then residual torque is reduced, but device complexity and manufacturing difficulty increase
Solution Approach 1:
Instead of using flared poles to achieve smooth torque characteristics, the invention inverts the approach by using straight cylindrical poles combined with a specific rotor pole configuration (alternating magnetized and salient non-magnetized poles) to achieve the desired torque profile while simplifying manufacturing.
4Volume of stationary object
If straight stator poles are used, then winding volume and ease of manufacture are improved, but magnetic flux collection is reduced
Solution Approach 1:
The invention uses a composite magnetic circuit design combining straight stator poles with a hybrid rotor structure featuring both magnetized permanent magnets and salient non-magnetized ferromagnetic poles. This composite approach compensates for the reduced flux collection of straight poles by utilizing multiple magnetic flux paths and sources.
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 motor achieves enhanced torque density, sinusoidal current torque, and reduced phase inductance, facilitating dynamic applications with improved copper filling and reduced magnetic losses, resulting in a 30-40% increase in motor constant Km compared to prior art.
Implementation Method 1
a rotor made of a ferromagnetic material core and having an alternation of magnetized and non-magnetized salient poles
Implementation Method 2
allowing for improved magnetic flux
Implementation Method 3
reduced variable reluctance torque
Data Source
Figure 1a
Figure 1b~2
Figure 3
AI summary
The invention relates to a polyphase electric motor comprising a stator (1) having at least three coils (33, 43, 36, 46, 37, 47) and made up of 12.K radially extending teeth and a rotor (2) having 5.K pairs of magnetic poles, K being equal to 1 or 2, the rotor (2) being made up of a core (150) made of a ferromagnetic material and having an alternation of 5K magnetised poles, and 5K non-magnetised salient poles, characterised in that the stator (1) has teeth (3, 6, 7, 13, 16, 17, 20, 21, 22, 23, 24, 25) with rectangular or trapezoidal cross-sections converging towards the centre of the motor.