Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
Here is the 1st hit to come up after a google search of "bldc pump motor control"@ 4pyros
Can you point to an example, where the motor is a BLDC type driven at a fixed frequency?
Its just to pump water to flowers....we don't want extra bits like flow sensors....are you saying we cant do it without flow sensors?.....surely theres some way that we can do it without flow sensors.......ie, just using the back emf signals to represent speed?
?? But won't the back-emf signal be constant if, as you say in post #1,surely theres some way that we can do it without flow sensors.......ie, just using the back emf signals to represent speed?
when the pump suddenly runs dry...after all, the motor speed does not increase
Braking
When the BRAKE pin is pulled below 1.4V, the low side
output drivers LA, LB, and LC are turned on and the high
side output drivers HA, HB, HC are turned off. Braking
causes rapid deceleration of the motor and current limiting is
de-activated, and care should be taken when using the
BRAKE pin. BRAKE is has an internal 4kΩ pull-up as
shown in Figure 10, and can be driven by a switch to ground,
an open collector or drain logic signal, or a TTL logic signal.
What did those "engineers" have to say?Ever put a amp meter on it to see if the input amp draw changes when the motor unloads? Odds are it does.
You can increase system efficiency even further by not using PWM at all," according to Dave Wilson, technical lead for Texas Instruments Motor Solutions Group. "Instead, use 100-percent duty cycle all the time and only switch the inverter transistors at the commutation boundaries. To control the motor’s speed, simply change the DC voltage driving the inverter transistors. This approach reduces the switching losses to almost zero on all phases, and it mitigates high frequency losses inside the motor."