Rotary Electric Machine With Dedicated Inverter Circuits
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Solution Overview
Problem
Rotary electric machines face issues such as local winding faults, short circuits, and eccentricities, which can lead to degraded torque and power output, overheating, and reduced reliability and safety in electric vehicles and hybrid electric vehicles.
Innovation Solution
Each stator coil in the rotary electric machine is connected to a dedicated inverter circuit, allowing for individual control and fault detection, with the controller adjusting current supply to faulty coils and applying asymmetric currents to compensate for eccentricities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional three-phase inverter is used to supply power to stator coils, then the device complexity is reduced, but the reliability decreases when local winding faults or short circuits occur
Solution Approach 1:
The patent divides the conventional three-phase inverter into multiple independent inverter circuits, with each phase having its own dedicated inverter circuit. This segmentation allows independent control and fault isolation, where a fault in one phase does not affect the other phases, thereby improving reliability and fault tolerance while managing device complexity through modular architecture
Solution Approach 2:
The patent introduces a controller as an intermediary that manages multiple independent inverter circuits. The controller coordinates the operation of each inverter circuit and implements fault detection and isolation strategies, enabling the system to maintain reliable operation even when faults occur in individual phases or coils
2Reliability
If stator coils are subject to local winding faults or short circuits, then the device complexity remains low, but the reliability and safety deteriorate due to overheating and failure propagation
Solution Approach 1:
By segmenting the power supply into independent inverter circuits for each phase and coil, the patent isolates faults to specific segments. When a local winding fault or short circuit occurs, only the affected segment is disconnected, preventing overheating and failure propagation to other parts of the system while maintaining operational safety
Solution Approach 2:
The patent converts the potentially harmful effect of faults into a beneficial fault tolerance mechanism. By implementing independent inverter circuits with individual control, the system can detect and isolate faults, transforming what would be catastrophic failures into manageable events that enhance overall system reliability and safety
3Reliability
If asymmetric currents are applied to compensate for eccentricities, then the reliability improves, but the device complexity increases due to selective coil control requirements
Solution Approach 1:
The patent implements dynamic control capabilities through independent inverter circuits that can adjust current magnitude and phase for each coil individually. This dynamic control enables real-time compensation for rotor-stator eccentricities by applying asymmetric currents to specific coils, improving reliability while the modular structure manages control complexity
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 arrangement enhances the reliability and fault tolerance of the rotary electric machine by containing local failures and mitigating the effects of eccentricities, preventing overheating and maintaining operational safety.
Implementation Method 1
an inverter may transform direct current (DC) power from a battery into alternating current (AC) power that is supplied to three conductors of a three-phase stator
Implementation Method 2
The three-phase AC power activates successive coils of the stator to produce a rotating magnetic field with a specified direction and speed. For example, the rotating magnetic field may be used to produce torque when coupled with a rotor having a permanent magnet
Data Source
AI summary
In some examples, a rotary electric machine includes a stator having a plurality of stator coils arranged in a circular pattern around a central opening configured for receiving a rotor. The rotary electric machine further includes a respective dedicated inverter circuit associated with each respective stator coil. For instance, each respective inverter circuit may be configured to convert direct current power to alternating current power to provide to the respective stator coil.