TIDA-010250: Target RPM and pole of motor

Hi, Shotaro san

 This is a reference design for appliances, so target speed should be below 4500RPM. and normally home appliances use a 2-6 poles motor.

However, in stead of using target speed, I would use maximum inverter output frequency, basically, with sensorless algorithm, assume maximum carrier frequency 15kHz, and we need minimum 50 switching pulses for each electrical motor phase cycle, then we can output maximum 300Hz current to motor, based on speed =60f/pairs, maximum speed is 18000RPM for two poles motor, 9000RPM for 4 poles motor, 6000RPM for 6 poles motor.   

If we need 100 switching pulses in each electrical motor phase cycle(motor phase current will be more sinusoidal), then max speed will be 9000RPM, 4500RPM and 3000RPM correspondingly.

Regards

Hely