Synchronous Machine Starting Device Abnormality Detection
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Solution Overview
Problem
Synchronous-machine starting devices face issues with normal torque application and rotor acceleration due to phase mismatch between the magnetic field and thyristor firing, leading to potential overheating and machine breakdown during initial rotation.
Innovation Solution
A synchronous-machine starting device that includes an electric power conversion unit, AC voltage detection, rotor position detection, and an abnormality detection unit to monitor the AC voltage in the armature, allowing for stable starting by detecting rotation abnormalities based on the number of times the AC voltage reaches a predetermined value during the startup period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a constant field current is supplied to the rotor during initial rotation, then a fixed magnetic field is produced for synchronous machine operation, but the field winding may overheat and cause machine breakdown due to insufficient rotor acceleration
Solution Approach 1:
The abnormality detection unit performs preliminary detection of rotation abnormalities before they cause overheating damage. By monitoring the AC voltage waveform during the period when constant field current is supplied, the system detects insufficient rotor acceleration early and can take corrective action before the field winding temperature reaches dangerous levels.
2Reliability
If the magnetic field and thyristor firing phase are out of phase, then normal torque cannot be applied to the synchronous machine, but continuous operation in this state leads to rotation abnormalities and potential breakdown
Solution Approach 1:
The abnormality detection unit continuously monitors the AC voltage waveform and provides feedback about rotation abnormalities. By detecting phase mismatch conditions through waveform analysis, the system can identify when normal torque cannot be applied and alert operators or control systems to correct the phase alignment, preventing prolonged operation in an abnormal state.
3Device complexity
If AC voltage detection is used for rotor position detection, then mechanical distributors and their associated wires are eliminated, but rotation abnormalities may go undetected without additional monitoring
Solution Approach 1:
The AC voltage detection unit serves multiple functions: it detects rotor position for synchronous machine operation and simultaneously monitors for rotation abnormalities. By analyzing the AC voltage waveform characteristics, the same detection system identifies both normal operational parameters and abnormal conditions, eliminating the need for separate mechanical distributors and additional monitoring equipment.
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
Enables stable starting of synchronous machines by detecting and addressing rotation abnormalities, preventing overheating and potential breakdowns by ensuring proper torque application and rotor acceleration.
Implementation Method 1
an AC voltage detection unit configured to detect an AC voltage in the armature of the synchronous machine
Implementation Method 2
a rotor generating a fixed magnetic field by being supplied with a field current
Implementation Method 3
an armature for generating a rotating magnetic field
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A synchronous-machine starting device for starting a synchronous machine (4) including an armature (ATU, ATV, ATW) for generating a rotating magnetic field and a rotor (RT) generating a fixed magnetic field by being supplied with a field current includes an electric power conversion unit (71) for converting supplied electric power into AC power for supply to the armature (ATU, ATV, ATW) of the synchronous machine (4), a rotor position detection unit (11) for detecting a position of the rotor of the synchronous machine (4) based on an AC voltage in the armature (ATU, ATV, ATW) of the synchronous machine (4) detected by an AC voltage detection unit (8), an electric power conversion control unit (19) for controlling the electric power conversion unit (71) based on the position of the rotor detected by the rotor position detection unit (11), and an abnormality detection unit (10) detecting a rotation abnormality of the synchronous machine (4) based on the AC voltage detected by the AC voltage detection unit (8) after supply of the field current to the rotor (RT) of the synchronous machine (4) is started.