Six-Layer Hairpin Winding Layout for Electric Machine Stator Loss Reduction
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Solution Overview
Problem
Electric vehicles with traction motors face limitations in range due to the weight and cost of battery packs, and high motor speeds lead to increased heat losses in stator windings, necessitating an improvement in electric machine efficiency.
Innovation Solution
The electric machine features a stator with a six-layer hairpin winding layout, where phase conductors are arranged in layers within stator slots with balanced quantities of shared and same slots, reducing stator losses at high rotational speeds by minimizing circulating currents and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high motor speeds are used to increase power output, then power capability is improved, but heat losses in stator windings increase
Solution Approach 1:
The stator winding is segmented into multiple layers (first layer, second layer, third layer, fourth layer, fifth layer, sixth layer) with specific conductor arrangements in each layer. This segmentation allows for optimized current distribution and reduced eddy current losses while maintaining high power output capability.
Solution Approach 2:
Different regions of the stator winding have different conductor configurations. Specifically, the winding includes both same slots (where conductors of different phases are placed) and shared slots (where conductors of the same phase are placed), creating local variations in electrical properties that reduce circulating currents and heat losses.
2Duration of action of moving object
If battery pack size is increased to extend vehicle range, then operating range is improved, but vehicle weight and cost increase
Solution Approach 1:
The six-layer hairpin winding layout creates periodic patterns in the stator slots with balanced quantities of same slots and shared slots. This periodic structure optimizes the magnetic field distribution and reduces iron losses, improving overall motor efficiency and extending vehicle range without increasing battery capacity.
3Ease of manufacture
If conventional winding layouts are used in stator slots, then manufacturing simplicity is maintained, but circulating currents and heat generation increase at high speeds
Solution Approach 1:
The patent transitions from traditional planar winding layouts to a three-dimensional six-layer hairpin winding configuration. Hairpin conductors are inserted vertically into the stator slots and bent at right angles, creating a layered structure that reduces circulating currents while maintaining manufacturing feasibility through standardized insertion processes.
Solution Approach 2:
The winding layout parameters are optimized by specifying exact layer configurations, conductor positions, and slot assignments. The balanced quantity of same slots and shared slots across six layers creates optimal electrical parameters that minimize losses at high rotational speeds.
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 reduced stator losses and increased torque production, enhancing the efficiency and range of electric vehicles by managing heat and current distribution effectively.
Implementation Method 1
A rotor extends axially and is disposed in the rotor chamber for rotating relative to the stator in response to the alternating current voltages carried by each of the plurality of phase conductors
Implementation Method 2
reducing stator losses at high rotational speeds by minimizing circulating currents and heat generation
Data Source
AI summary
An electric machine is provided that includes a stator defining a rotor chamber and a plurality of stator slots disposed circumferentially about the stator. The stator includes a plurality of phase groups each including a plurality of circuits. Each circuit includes a plurality of winding sets of a plurality of phase conductors connected in series for carrying an alternating current voltage. A rotor is disposed in the rotor chamber for rotating relative to the stator. The phase conductors are laid in a plurality of layers of the plurality of stator slots. Stator slots that include phase conductors carrying different phases are shared slots and stator slots that include phase conductors carrying the same phase are same slots. The circuits are arranged with balanced quantities of same slots and shared slots for reducing stator losses at high rotational speeds of the rotor relative to the stator.