White goods application:
Sensorless Brushless DC Motor Control with Infineon C164CI.
by Nicola Bergamin (see contacts info)

Overview


BlueWind developed this Application Software in collaboration with the Infineon Automotive and Industrial Group.

White goods appliances market is increasingly introducing electronically controlled motors: the purpose is getting better overall performance while maintaining competitive prices: this is, for example the case for the refrigerator: It is certainly true that the brushless, commutated motor is more expensive compared to the traditional induction counterpart: it requires dedicated control circuitry and power conversion stage.
Nontheless, the global result is an increase in the appliance's thermal efficiency, thus leading to lower overall costs.

System details

Brushless Application Software

The BLDC Application software is intended to give the customer a ready to use platform: it is conceived to be used upon an Infineon Motor Control StarterKit(see), useful for either Brushless, V/F Induction or Field Oriented Control software modules.
A three phases, three poles brushless DC motor has been used.
The Infineon starter kit ASM750 (265 V AC maximal voltage supply), is based on C164CI microcontroller (16-bit, 100ns minimum instruction cycle time).
Main features of the Application Software are:
Startup Procedure and positioning (phasing)
Single shunt current acquisition
Hall Sensor based position feedback
Back-EMF Sensorless position detection
Matlab Modeling and simulation tools
Diagnostic/Debug software
In order to control the torque and the speed of a brushless DC one needs to know the rotor position, the current in each phase, and the speed. With sensorless approach the position is determined through the evaluation of zero crossing of back EMF, which permits to use motors without Hall position sensors. By using a single shunt placed in the DC line along with the position information, it is possible to determine the instant phase current, while the speed is evaluated using the zero crossing frequency. Learn more in the Brushless Technical Note
See other Infineon Products application notes at BlueWind Applications Page

References

Infineon 16-bit microcontrollers: http://www.infineon.com/

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