PING Tim Wescott

Well, actually, I have a VERY simple six-step drive using just a small CPLD. As long as you are doing six-step and have Hall signals from the motor and PWM from some outer controller, then the drive doesn't need much smarts. The PWM and direction signals plus the Hall signals tell you which transistors to turn on, and handle the dead time. A current limit resistor and comparator add in cutoff of the PWM if current limit is exceeded.

Jon

Well, sort of. Generally, brushless motors have fewer stator slots than similar DC motors would have armature slots. A 2-pole brush motor only has

Back EMF is certainly an important feature of brushless motors, as well as the brushed variety.

Jon

On Thursday, 9 February 2017 02:54:11 UTC+1, Lasse Langwadt Christensen wr ote:

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Today the motor control SW for embedded micros are free, and the Cortex M0 micro price is so low that I do not think you will benefit anything from ma king an IC. The IC's are for the people who don't understand the workings o f the micro using FOC (Field Vector Control) and are willing to pay more fo r not doing any work

Just look into the STM32 FOC library and check the app notes. It's quite si mple

A Cortex M0 can be had for less than 30 cents, and you normally need a micr o anyway in your system

Cheers

Klaus

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It doesn't get much simpler than this:

Cheers

Klaus

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M0 micro price is so low that I do not think you will benefit anything fro m making an IC. The IC's are for the people who don't understand the workin gs of the micro using FOC (Field Vector Control) and are willing to pay mor e for not doing any work

e simple

micro anyway in your system

For 3 phase BLDC remove one halfbridge and connect in start configuration.. .

Cheers

Klaus

you could have the coils stationary in brushed motor if you really wanted to, just make stator the rotor and vice versa and bring power in through slip ring or brushes

the video sensorless controller, that's a bit more complicated

Den torsdag den 9. februar 2017 kl. 23.25.38 UTC+1 skrev snipped-for-privacy@gmail.c om:

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cortex M0, 3*halfbridge gatedrivers, 3.3V buck, 12V LDO, 4x opamp, comparat or

in a 7x7mm package

budgetary price $1.6

Oh you are such a killjoy.

Blech.

You could make an outrunner brushed motor, with the magnets inside and the coils on a spinning shell. Not only would the coils be outside, but you wouldn't need a fan.

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Jim-out-of-touch-with-reality-Thompson didn't read enough of my post - or p erhaps didn't understand it well enough - to realise that I was boasting of having done just that. It was back at EMI Central Research in 1978, and I was a bit peeved to have had to do it in TTL - we had a development system for a microcontroller, but it was booked up solid for more than a year, and the programmable bit of the system ended up as a PROM look-up table.

The circuit was for a motor-driven mechanical ultrasound scanner, and I got it to go a bit faster than we'd thought we could, and quite a bit faster t han the mechanical engineers had expected.

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M0 micro price is so low that I do not think you will benefit anything fro m making an IC. The IC's are for the people who don't understand the workin gs of the micro using FOC (Field Vector Control) and are willing to pay mor e for not doing any work

e simple

micro anyway in your system

ator

STSPIN is just for those people that cannot connect the dots themselves :-)

You can shave of 1 USD of that solution doing it your self

Cheers

Klaus

Do they come with foot switches too?

God, save me. I can't believe this thread with all the so called Pro's in here, especially slug-man with his offerings, which of course is wrong, too.

Jamie

Yes, but there is a general confusion in the industry

PMSM has sinewave current and sinewave BEMF

BLDC has trapezoidal current and trapezoidal BEMF

There is not unique phase delay, it depends on the number of poles

Cheers

Klaus

God said you're not worth saving. Too brain-dead.

FYI:

If you look at specs for a small BLDC motors ( the kind often used in RC hobbies ) the rated voltages vary with different winds but the max rpms do not.

The conclusion from this is that the max rpm is a self destruction limit for the rotor - and the specified max voltage is one that keeps the rpms to a safe level.

So, it ain't so smart to go exceeding it.

.... Phil

Please don't associate your failings to me. You are up there with Slow-Man, ignorant and self overrated.

Jamie

Jamie

Jamie might not have a high opinion of himself, but he clearly doesn't appreciate quite how dim and ignorant he really is - the fact that he's brave enough to post his moronic misconceptions here makes the point all too obvious, all too frequently.

st.

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amely Bill.

hobbies ) the rated voltages vary with different winds but the max rpms do not.

for the rotor - and the specified max voltage is one that keeps the rpms to a safe level.

Perhaps. Which might have been why the mechanical engineers dragged me off to talk to the local agents for the motor manufacturer.

The motor I was using didn't have a maximum rotational speed in it's data s heet. More recent units may be better specified.

The data sheet did give data for rotation rates higher than you could get w ith the 12V that the stalled motor could survive. It's all forty years ago so the fine details aren't entirely accessible, but there was a 3V version of the same motor, and we'd have looked a bit silly if we'd limited to the