The Stator Winding section in Motor Wiz is central to electric motor performance, as it directly determines the electromagnetic torque, back-EMF, efficiency, and thermal behavior. From a user perspective, this section allows engineers to customize winding configurations and instantly visualize the impact on torque ripple, current distribution, and efficiency curves, making it a key interface for motor design optimization.
Motor Wiz enables users to select winding type interactively, slot shift, phase number, layering, and parallel circuits, providing detailed simulation outputs for electromagnetic, thermal, and mechanical performance. This interactivity is critical for EV and industrial motor designers who need to balance electrical performance with manufacturability and cooling requirements.
i. Slot Shift
Definition: Slot shift refers to the number of slots by which the winding coils are shifted around the stator to achieve better phase alignment or reduce undesirable harmonics.
Effect: It changes the phase sequence of the windings, which helps in balancing the electromagnetic field distribution.
AMD Winding Algorithm: The Advanced Machine Design (AMD) winding algorithm optimizes the stator winding configuration to achieve minimal torque ripple and optimal performance.
Example:
Consider a 3-phase winding system where the initial phase sequence is (a, b, c).
Applying a slot shift of 1 (Nslot_shift_wind = 1) transforms the sequence to (b, c, a).
This rearrangement helps in achieving better sinusoidal back EMF, reduced cogging torque, and improved efficiency.
ii. Number of Phases
Definition: The number of electrical phases in the winding.
Common Configurations:
Single-phase: Used in small applications (fans, home appliances).
Three-phase: Most common in industrial and automotive applications, providing a balanced rotating field with higher efficiency.
Multi-phase (5-phase, 9-phase, etc.): Used for special applications requiring higher fault tolerance and smoother torque.
iii. Layer Configuration
The layer defines how conductors are arranged within the slot. There are three main types:
Single-layer winding:
Each slot contains only one coil side.
Used in low-cost, simple designs.
Provides higher inductance but may result in higher space harmonics.
Double-layer overlapping winding:
Each slot contains two coil sides, one at the top and one at the bottom.
More common in industrial motors due to better harmonic suppression.
Provides smoother torque and lower cogging effects.
Double-layer non-overlapping winding (Concentrated winding):
Coils are wound separately around the teeth.
Used in high-performance PM motors for high power density.
Results in lower copper loss and improved efficiency.
iv. Coil Pitch (Throw)
Definition: Throw (or coil pitch) refers to the distance in slots between a conductor of a certain phase and its return conductor.
Measurement: It is measured in number of slots.
Example:
Full-pitch winding: The coil spans exactly one pole-pair (e.g., if there are 12 slots and 4 poles, the throw = 3 slots).
Short-pitched winding: The coil is shorter than a pole-pair, reducing harmonics but slightly lowering fundamental voltage.
Long-pitched winding: Used to achieve specific harmonic suppression.
v. Parallel Circuits
Definition: Parallel circuits refer to the number of independent electrical paths per phase.
Impact on Motor Performance:
Increasing the number of parallel circuits reduces the phase resistance and improves current distribution.
Used to accommodate different voltage and current levels.
Common Configurations:
Single parallel circuit per phase: Used in low-power applications.