Electric Motor Control with Fault Tolerant Impedance Adjustment
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Solution Overview
Problem
Existing electric motor control systems are heavy and lack compactness, and controlling multiple motors connected to a single load requires a mechanical disconnect system to prevent drag torque and internal heating when a motor fails, which complicates the system design.
Innovation Solution
The electric motor system incorporates a 3-phase permanent magnet motor design with separate phase and control windings, where the control winding is wound with a 3:2 turns ratio relative to the phase winding, allowing for efficient motor control and fault management by adjusting the impedance of the phase windings to prevent drag torque and heating when a motor fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If control electronics are added to electric motors, then motor control capability is improved, but system weight and size increase
Solution Approach 1:
The control electronics are integrated directly into the motor assembly, merging the motor and controller into a single unit. This eliminates separate control components and reduces overall system weight and size while maintaining full motor control capability.
Solution Approach 2:
The control electronics are designed to serve multiple functions including motor control, fault detection, and protection mechanisms within a single integrated system, reducing the need for separate components and thereby reducing weight.
2Reliability
If multiple motors are connected to drive one load, then system redundancy is improved, but system complexity increases due to need for mechanical disconnect system
Solution Approach 1:
The mechanical disconnect system is replaced with an electrical control system that can electrically disconnect failed motors from the load. This substitution eliminates complex mechanical components while maintaining the ability to isolate failed motors, thereby reducing system complexity while preserving redundancy.
Solution Approach 2:
The system uses electrical parameter changes (such as switching control signals) to disconnect motors instead of mechanical movement. This allows for simpler, faster, and more reliable motor isolation without requiring physical disconnect mechanisms.
3Reliability
If mechanical disconnect system is added to prevent drag torque, then motor protection is improved, but system weight and complexity increase
Solution Approach 1:
The mechanical disconnect system is replaced with an electrical control system that can electrically disconnect failed motors from the load. This substitution eliminates complex mechanical components while maintaining the ability to isolate failed motors, thereby reducing system complexity while preserving redundancy.
Solution Approach 2:
The control system automatically detects motor failures and independently initiates disconnection of failed motors without requiring external mechanical intervention. This self-service capability simplifies the system by eliminating the need for complex mechanical disconnect mechanisms.
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 enhances motor control efficiency, reduces system weight and size, and provides redundancy to minimize drag torque and heating in case of motor failure, improving overall system reliability and compactness.
Implementation Method 1
The control winding is wound with a 3:2 turns ratio relative to the phase winding, allowing for efficient motor control and fault management by adjusting the impedance of the phase windings
Implementation Method 2
a permanent magnet (PM) electric machine is depicted. The motor has a rotor with permanent magnets, interposed by spacers, which rotor is mounted for rotation relative to a stator
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Motor control at faulted condition. A common rotor is driven by two stators each controlled by a power supply. Each stator comprises an auxiliary winding supplied by DC current to saturate a yoke section during normal operation. During a faulty short circuit at the windings of the first stator the power supply of the first stator is cut off and said yoke section is no more saturated, thereby increasing the total impedance of the main winding. Advantage: The damaged first stator produces less drag on the rotor. The rotor can keep running, driven by the second stator alone.