Brushless dc motor and asynchronous machine and the comparison of frequency converter although the ac variable frequency speed regulation is very common, but the frequency control of motor speed is limited by the low efficiency of induction motor, the motor is running at low speed torque smaller, harmonic loss is big, the speed rate of change is big, poor dynamic performance such as missing; Although the speed loop vector control or direct torque control when its frequency converter can meet the demand of performance, but the purchase cost on the high side, and the efficiency of the induction motor, power factor, low fever still can't improve. we compare to inverter energy-saving modification in the injection molding machine industry, brushless dc motor of integrated power saving rate is above 20%, higher than ac frequency conversion was not reduced injection molding machine production speed,Frequency converter to reduce about 3%)By 20 ℃, the motor temperature rise. in the fan pump load on the application of the compressor, power --Speed curve should actually be reached third power relation, but using inverter driven induction motor the curve may be only the square proportion or less; Adopts brushless dc motor drive the curve can be close to the third power curve characteristics, power saving effect is better. ①BLDCM (Brushless dc motor)
3. (2) efficient asynchronous machine general asynchronous machine
(4) brushless dc motor controller (5) inverter, yuntai motor
