Armature Winding Layout to Reduce Parallel Circuit Current Imbalance
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Solution Overview
Problem
Existing rotary electric machines with large-capacity generators face issues of current imbalance and increased loss due to circulating currents between parallel circuits, which are not adequately addressed by existing solutions that either increase or fail to reduce the number of inter-polar connection rings.
Innovation Solution
The rotary electric machine design incorporates a two-pole, three-phase armature winding with fifty-four slots, featuring top and bottom coil pieces arranged in specific sequences and connected via jumper connections, reducing the number of inter-polar connection rings and minimizing current imbalance by optimizing the arrangement of parallel circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the number of inter-polar connection rings is reduced, then the device complexity is decreased, but the current imbalance caused by circulating current between parallel circuits increases
Solution Approach 1:
The armature winding is divided into multiple parallel circuits (first and second parallel circuits) with specific connection patterns. Each parallel circuit is further segmented into coil groups connected in series, allowing the winding to be configured such that circulating currents are minimized while using fewer inter-polar connection rings. The segmentation enables independent current paths that reduce the harmful circulating currents.
Solution Approach 2:
Different regions of the armature winding are assigned different connection characteristics. The first and second parallel circuits have distinct connection patterns to the commutator segments, creating local variations in current distribution. This local quality differentiation allows the system to reduce overall complexity while maintaining balanced current distribution through strategic local connection designs.
2Reliability
If the number of inter-polar connection rings is increased, then the current imbalance is restrained, but the device complexity increases
Solution Approach 1:
Multiple coil groups are merged into two main parallel circuits that share common connection paths to the commutator. By combining several series-connected coil groups into just two parallel circuits, the invention reduces the number of inter-polar connection rings needed while maintaining balanced current distribution. This merging approach achieves current balance without proportionally increasing connection ring count.
Solution Approach 2:
The armature winding is pre-configured with specific connection patterns during manufacturing, where the first and second parallel circuits are established with predetermined connections to commutator segments. This preliminary arrangement ensures that circulating currents are minimized from the outset, allowing the system to operate with fewer inter-polar connection rings while maintaining current balance.
3Temperature
If parallel circuits are used to reduce current per armature winding, then the electromagnetic force and temperature rise are moderated, but the circulating current between parallel circuits causes loss
Solution Approach 1:
The armature winding is segmented into multiple series-connected coil groups within each parallel circuit. This segmentation creates more uniform current distribution and reduces circulating currents between parallel circuits, thereby reducing energy loss. The segmented structure also improves heat dissipation by distributing current paths, which moderates temperature rise in the armature winding.
Solution Approach 2:
The invention optimizes the connection parameters of the parallel circuits to the commutator segments, specifically designing the connection pattern to minimize circulating currents. By changing the connection parameters (which segments each parallel circuit connects to), the system reduces energy loss from circulating currents while maintaining the temperature-moderating effect of parallel circuit configuration.
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 effectively lessens the loss of the armature winding and reduces current imbalance, providing a more efficient configuration for large-capacity generators by strategically arranging coils and connection rings.
Implementation Method 1
Large currents outputted from the large-capacity generator may cause the armature winding to generate a large electromagnetic force
Implementation Method 2
Large currents outputted from the large-capacity generator may cause the armature winding to generate a large electromagnetic force and a high heat value
Data Source
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AI summary
A rotary electric machine comprises a two-pole rotor, a stator core having 54 slots housing a 3-phase armature winding in two layer with three parallel circuits each. One of the circuits includes an inter-polar connection ring (8), connecting two different poles, whereas the two others include a connection ring (7) inside the same pole. Two phase belts (3,9) per phase are foreseen, each comprising two parallel circuits. The sequence of the first and second parallel circuits of the first phase belt (3) is viewed from the phase belt center (4), the first and second parallel circuits are arranged in a sequence of the first, second, first, first, second, first, first, first, and second parallel circuits in the top coil pieces (1) and in the bottom coil pieces (2). For the sequence of the second and third parallel circuits of the second phase belt (9), the arrangement is analogous.