Common methods include changing the resistance of the excitation circuit of the exciter, changing the additional excitation current of the exciter, changing the conduction angle of the thyristor, and the like.
Today, the main point here is: the method of changing the conduction angle of the thyristor, which is based on the change of the voltage, current or power factor of the permanent magnet synchronous motor, and accordingly changes the conduction angle of the thyristor, so that the generator The field current changes.
This means generally consists of a transistor, thyristor electronic components, and has a sensitive, rapid, failure-free region, output power, small size and light weight advantages. In the event of an accident, the overvoltage of the permanent magnet synchronous motor can be effectively suppressed, and the purpose of rapid demagnetization can be achieved.
The automatic adjustment excitation device is generally composed of a measurement unit, a synchronization unit, an amplification unit, a adjustment unit, a stabilization unit, a restriction unit, and some auxiliary units. The measured signal (such as voltage, current, etc.) is compared with the given value after being transformed by the measuring unit, and then the comparison result (deviation) is amplified by the preamplifier unit and the power amplifying unit, and used to control the conduction of the thyristor. The angle is to achieve the purpose of adjusting the excitation current of the permanent magnet synchronous motor.
