The national standard "Permanent magnet synchronous motor energy efficiency limit value energy efficiency grade" is only gb30253-2013 "Permanent magnet synchronous motor energy efficiency limit value energy efficiency grade", which is applicable to 0.55-375kw, 2-16 pole asynchronous start 1140V below three-phase permanent magnet synchronous motor. The efficiency of high voltage permanent magnet synchronous motor can only refer to the standard ceeia229-2015 "TYC series (IP23) High efficiency High voltage permanent magnet synchronous motor Technical conditions" ceeia230-2015 "TYKK series (IP44) High efficiency High voltage permanent magnet synchronous motor Technical Conditions".

(2) The starting current multiple of permanent magnet synchronous motor is about 9 times, which is 10% larger than the asynchronous motor.

(3) The starting mode of permanent magnet synchronous motor cannot be simplified. Because in the case of step-down power supply, the asynchronous starting torque drops more than the asynchronous starting torque of the asynchronous motor, which will lead to starting difficulties.

(4) For the self-starting characteristics of permanent magnet synchronous motor the feedback current when the system is short circuit, the parameters of different equipment manufacturers are very different. The application of permanent magnet synchronous motor, due to the difficulty in obtaining relevant data, brings some uncertain factors to the short-circuit level startup calculation verification of plant power system.