The main difference between the Synchronous Motors produced by LT SIMO Motor and ordinary asynchronous motors TDMK Motor in operation is that when the synchronous motor is running, the angle between the armature voltage vector and the rotor pole position must be within a certain range, otherwise the system will lose step. Therefore,when the synchronous motor is frequency-converted and speed-regulated, this angle must always be controlled to change within the allowable range. This is the main difference between synchronous motor frequency conversion and Asynchronous Motor frequency conversion. The following will briefly introduce the difficulties encountered in thesynchronous motor frequency conversion speed regulation process and the corresponding solutions of the maxf frequency conversion device:
Synchronous motor starting and excitation process
There are usually two ways to start asynchronous motor: one is to excite first and start synchronously; the other is to start asynchronously and then excite in the same polarity. For synchronous motor frequency conversion starting, excitation is first used and synchronous starting is adopted, but incorrect rotor position judgment often leads to motor starting failure. For synchronous motor frequency conversion speed regulation, it is easy to adopt asynchronous starting and forward polarity excitation. Therefore, the maxf frequency conversion device performs asynchronous soft starting on the synchronous motor to achieve the rated starting torque, and starts the synchronous motor to about 8hz for forward polarity excitation. The specific excitation size and excitation frequency can be debugged and determined according to different application occasions. At this point, after the angle between the motor rotor magnetic field and the stator magnetic field has a small amount of damped oscillation, the motor rotor magnetic pole is reliably attracted by the stator magnetic pole, and the synchronous motor enters the synchronous operation state. The inverter gradually accelerates to the given frequency according to the preset acceleration. At this time, the angle between the synchronous motor armature voltage vector and the rotor magnetic pole position gradually increases to a certain constant value, and the motor rotor magnetic pole is gradually accelerated to the desired speed under the attraction of the stator magnetic field, and the synchronous motor starting process is completed.