How to control the motor current?

Update:13 Jul 2020
Summary:

Many friends are very interested in how to control the […]

Many friends are very interested in how to control the current of the liming motor. This is indeed a key and difficult task. In order to facilitate your operation and solve your doubts, I will introduce some related content to you. You can be serious Read it.

If the external inverter bridge is grounded through a resistor Rs to be used as the current sampling. The sampled voltage should be input to the current from pin 9 to pin 15, and the comparator is detected in this way. A reference voltage of one hundred millivolts can be set at the inverting input of the comparator, and this voltage can be used as a reference for current limiting.

It can be during the period when the sawtooth wave of the liming motor oscillator rises. If the current is too large, flip the comparator at this time, and then reset the Rs trigger, you can turn off the drive output, so there is another function, which is to limit the current Continue to increase.

During the period when the sawtooth wave of the oscillator falls, the flip-flop can be reset to turn on the drive output. Through this comparison of the periodic current, the effect of current limiting is achieved. If the allowable current is set to Imax, then the sampling resistance can be selected according to the following formula: that is, Rs=0.1/Imax, before the input of pin 9, by setting RC The low-pass filter can avoid the occurrence of erroneous current detection caused by commutation spikes.