Multi-Phase Electric Machine Switching for Smooth Star-Delta Transitions
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Solution Overview
Problem
Multi-phase electric machines experience jolts during configuration changes between star and delta configurations, which can lead to mechanical stress and reduced driving efficiency.
Innovation Solution
The machine is partitioned into groups of phases powered by separate inverter power circuits, allowing for independent configuration switching between star and delta configurations, with a controller managing the transition to minimize torque fluctuations and reduce jolts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the phases are interconnected in star or delta configurations during operation, then the machine can operate in different modes, but torque jolts occur during configuration changes
Solution Approach 1:
The patent divides the six-phase machine into two independent three-phase systems (first and second three-phase systems), each capable of independent star/delta configuration changes. This segmentation allows one system to maintain torque while the other transitions, preventing torque jolts during configuration changes
Solution Approach 2:
The controller pre-coordinates the configuration changes of the two three-phase systems so that when one system changes configuration, the other system is already in a state that compensates for the transition. This preliminary coordination ensures continuous torque output without jolts
2Productivity
If configuration changes are made during operation, then driving efficiency is improved, but mechanical stress increases
Solution Approach 1:
By segmenting the six-phase system into two independent three-phase systems with separate control, the patent enables configuration changes to be distributed across both systems. This prevents sudden mechanical stress concentrations that would occur with simultaneous configuration changes in a unified system
Solution Approach 2:
The patent ensures continuous torque production during configuration changes by having one three-phase system compensate for the other during transitions. This continuity eliminates torque gaps and reduces mechanical stress on drivetrain components
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 approach reduces torque jolts during configuration changes, enhances driving smoothness, and extends the lifespan of mechanical components by optimizing torque distribution and reducing current requirements.
Implementation Method 1
an inverter power circuit that controls the flow of current in the various phases
Implementation Method 2
the three of the six-phase stator windings of the U1 phase, the V1 phase, and the W1 phase are respectively connected to the three output phase terminals (U, V, W) of the first inverter
Data Source
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AI summary
A multiple-phase electric machine provided with multiple inverter power circuits is described herein. The present multiple-phase electric machine aim at performing configuration changes while reducing the loss of torque when machines are switched between configurations. This is done by forming groups of phases defining machine portions that are powered by a separate inverter power circuit and by switching the machine portions separately with controlled switching devices.