st7mc or st8 for now sensorless BLDC project

[circaeng]

Posted on December 28, 2009 at 14:01

st7mc or st8 for now sensorless BLDC project

[circaeng]

Posted on May 17, 2011 at 10:16

Hi

I am starting a project to control a sensorless BLDC motor. I am not sure what is the best chip/kit to start with, the st7mc or st8 based kit I need the most configurable platform between the two choices since I am trying to self start a permanent magnet based alternator ( not originally designed to be a motor) Opinions appreciated Thank You Patrick [ This message was edited by: circaeng on 26-11-2009 04:25 ] [ This message was edited by: circaeng on 26-11-2009 04:34 ]

[tomas23]

Posted on May 17, 2011 at 10:16

It highly depends on the method you like to use: 6-step (called trapeziodal, or block commutation) or sinusoidal, on the maximum speed, availability of sensors (hall, encoder), number of pole pairs, your experience in motor tuning etc.

The ST7FMC has few advantages: the sensor circuitry (z-crossing, demagnetization) is managed by HW, there exists control panel that can help to tune the application in almost real-time, and has better control in really high speeds (up to 200 kRPM * pole-pair). The STM8 is cheaper, because it doesn't allocate >50% of silicon with the MC peripheral (;-)), but all sensors are managed via ADC readings, thus decreasing switching resolution at very high speeds. Give more details for discussion!