Motor fault when quickly changing speed


I’m currently working on a RC car project. Im using the MC33926 Shield on my Arduino - only M1 being connected. The motor itself is basically just an cordless drill from BOSCH (like the BOSCH PSR 14,4-2). Im using the battery provided with the drill. I just connected the M1A and M1B connections to the terminals of the drill and the power from the battery goes to VIN and GND of the shield - It runs perfectly, but when I quickly change the speed (like from 270 to 0, 400 to 0) the motor detects a fault. When i slowly lower the speed, everything works fine. Its just as soon as the speed is being changed quickly that I get those problems. The behavior occurs when the speed is bigger than ~250. The current at a speed of 250 is about 2.4 amps, at 400 it is about 4.6 amps.


Does the fault occur when you go quickly from stopped to 270 or 400? The MC33926 shield is only rated for 3A continuous and 5A peak, and from the numbers you mentioned (e.g. 4.6A at 400 speed), it sounds like there could be much higher peak currents in your system. For example, when the motor goes from full speed forward to full speed reverse quickly, it could draw upwards of twice the stall current. You might consider limiting your maximum duty cycle or adding some acceleration and deceleration ramping to see if that helps.