Electric Motor Starting Torque via Damper Winding Self-Service
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Solution Overview
Problem
Synchronous motors, particularly in aircraft, face challenges in starting torque generation due to the absence of starting torque, necessitating an auxiliary power unit to supply power for an alternating current exciter during asynchronous starting, which increases complexity and weight.
Innovation Solution
A method involving asynchronous starting by applying a starting current to the main machine's stator to induce a damper current in the main rotor's damper winding, generating starting torque, and transitioning to synchronous mode by supplying running current from the exciter rotor, eliminating the need for external AC excitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If an auxiliary power unit is used to supply power to the AC exciter during asynchronous starting, then the synchronous motor can generate starting torque, but the device complexity and weight increase
Solution Approach 1:
The damper winding on the main rotor serves dual purposes: it provides starting torque during asynchronous starting and simultaneously generates AC voltage during synchronous operation to power the exciter, eliminating the need for external AC excitation equipment
Solution Approach 2:
The damper winding is designed to perform multiple functions: generating starting torque during asynchronous starting and producing AC excitation voltage during synchronous operation, making the system self-sufficient
2Force
If an auxiliary power unit is used to supply power to the AC exciter during asynchronous starting, then the synchronous motor can generate starting torque, but the weight increases
Solution Approach 1:
The damper winding generates its own AC voltage during synchronous operation to power the exciter, making the system self-service and eliminating the need for additional AC excitation equipment that would increase weight
Solution Approach 2:
The invention extracts and utilizes the AC voltage generated by the damper winding during synchronous operation to power the exciter, removing the need for separate AC excitation equipment and reducing overall system weight
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 method provides efficient starting torque without additional AC excitation circuitry, reducing weight, size, and maintenance, resulting in a more reliable, cost-effective, and performance-enhanced system.
Implementation Method 1
applying a starting current to the stator of the main machine to induce a damper current in a damper winding of the main rotor to generate a starting torque
Implementation Method 2
induce a damper current in a damper winding of the main rotor to generate a starting torque that initiates the rotation of the common shaft
Data Source
AI summary
A method for starting an electric motor, the motor having a main machine, exciter, and permanent magnet generator (PMG), each having a stator and a rotor, with each rotor mounted to a common shaft, the method comprising starting the main machine in an asynchronous mode by applying a starting current to the stator of the main machine to induce a damper current in a damper winding of the main rotor to generate a starting torque that initiates the rotation of the common shaft, and then running the main machine in synchronous mode by supplying running current from the exciter rotor to the main machine rotor.