User Manual

Table 4-3. High Voltage Evaluation Hardware Set Specifications
Motor Characteristics:
Motor Type
6 poles, three phase, star con-
nected, BLDC motor
Speed Range: 2500 rpm (at 310V)
Max. Electrical Power: 150 W
Phase Voltage: 3*220V
Phase Current 0.55A
Drive Characteristics:
Speed Range < 2500 rpm
Input Voltage: 310V DC
Max DC-Bus Voltage 380 V
Control Algorithm Speed Closed Loop Control
Optoisolation Required
Load Characteristic: Type Varying
Sensorless Drive Concept
3-Phase BLDC Motor Control with Sensorless Back-EMF, ADC, Zero Crossing, Rev. 3
Freescale Semiconductor 13
Preliminary
4.2 Sensorless Drive Concept
The chosen system concept is shown below. The sensorless rotor position detector detects the Zero Crossing
points of Back-EMF induced in non-fed motor windings. The obtained information is processed in order to
commutate energized phase pair and control the phase voltage, using Pulse-Width-Modulation.