FOC with STSPIN32F0B: Phase Signal

Question

Hello ST Community,in my application I use an STSPIN32F0B in FOC.The design is similar to the STEVAL-SPIN3202 demo board. I used the STSPIN32F0A in Motor Control Workbench to generate the code (STSPIN32F0B is not in the Motor Control Workbench). I use it to control a BLDC motor sensorless. PWM frequency is 20kHz and the deadtime 900ns. The control of the motor works fine.the only thing that strikes me as strange is the oscillogram of the 3 phases. Here there are sporadic short intermediate pulses between the 20KHz pulses (see oscillogram)Do you have any idea what is happening here?Thank you very muchBest regardsFranz

Enrico Poli · Accepted Answer

Hello Franz,Welcome to the Community.I added the STM32 Motor Control topic to your post because it is more related to the control algorithm than to the hardware.The pulses in the power stage outputs are injected by STMicroelectronics' single-shunt algorithm in order to read the phase currents required by the FOC.In fact, the FOC needs at least 2 of the 3 motor currents to be executed and, due to the limit of the single shunt topology, it is not always feasible using a standard PWM modulation. The ST patented technique for current sampling takes care of this critical cases.Kind RegardsEnrico

Cristiana SCARAMEL · Answer

Hello @FStad.1​,did @Enrico Poli​ 's answer above resolve your doubts?If yes please "Select as Best" button to close the topic.

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