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dc to dc converter
That would be a terribly small duty cycle for a buck. You might want to use two stages, or a flyback topology (which would also give you isolation).
You can probably look up something like a "thermal switch" or a "thermostat" on digikey or equivalent... Usually these have different thresholds for turn on and turn off.
Servo motor question
Hi,
I think what makes a motor a servo is the way you control it (in a closed loop fashion). Therefore, three phase synchronous and asynchronous motors can be used as servo motors. The methods used to control these two types of motors are different, because of the fact...
bldc low speed
Hi,
If the same motor/sensor assembly worked better with a different drive, it is likely that your problem is in your control loop. Try changing your controller gains and see if it helps.
Re: Simple question!
I believe they are the same thing (peak value).
In A x sin(wt), A is the magnitude/amplitude.
If you have a sine wave and feed it to an amplifier, you will increase its amplitude (or magnitude), and possibly get a phase shift.
Regards,
BLDC pwm technique
If you increase the PWM frequency, your mosfets will heat up more, but your AC ripple current will be smaller. On the other hand, as your ripple increases you will get more core losses in your motor. The maximum frequency will be dictated by your mosfets' cooling and the PWM...
Hi,
You could use the same voltage you use for the digital side, with some capacitance and possibly a linear regulator, but you'd have to be careful with your grounding (connect analog and digital grounds at one point).
capacitor on output of switch mode
Are you sure about that output ripple requirement ? This is going to be quite difficult to achieve. I'm curious how you'll get there. Good luck !
to to count with qei
Hi,
I suppose you have an H bridge to drive your motor. In this case, if duty cycle is >50% you'll give positive voltage and rotate positively, and vice versa.
If you want to do position control, you can use the encoder and use the difference between desired and actual...
my ups not working
Looks like the bandwidth of your output filter is a little bit too high. I'd recommend increasing that 0.1uF capacitor.
Also, make sure you have some deadtime in your switching commands to prevent shoot through.
three wire hdd motor
Yes, it'll be an interesting project !
You can use the 4th wire to measure the back-emf of the motor on the unused phase in order to implement a sensorless algorithm. You can use the zero crossing points of the back emf to run the motor at moderate to high speeds.
A lot of...
bldc motor
hi !
Yes, you should be able to run your BLDC with a controller. Since you don't have position sensors, you'll need a sensorless one, or an open loop one, and you'll need to tune it.
If you are using a uC, you can directly implement code to control the motor (with a 3 phase FET...
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