I am thinking to order “Pololu High-Power Motor Driver 18v25 CS” and using on my switching power supply. The task is to load large current (10-30A) to the transformator that performs 12.5V->3000V working on 10-30kHz. According to the manual, I decide to use “Locked-antiphase” mode, so that I put PWM to DIR pin. What I need is to monitor the current that my transformator consumes. Is it possible to do so, or, I need to order additional ACS714/ASC715 carrier board, and install it between my V+ and board V+?
Unfortunately, I don’t have a great answer for you. The current sensor on the 18v25 CS measures the motor current, and in general, motor current is not necessarily the same as supply current. For example, if you use your motor in drive-brake mode, the motor is disconnected from the power supply during the braking period, but current continues to circulate through the motor (i.e. motor current does not equal supply current).
I’m not exactly sure how much of a disconnect there is between motor current and supply current in locked-antiphase mode. I suspect there will at least be some losses in the driver, and the disconnect could be quite large if you do not use a high-enough PWM frequency (where “high enough” is a function of your motor inductance).
Because the answer is dependent on your system and the specifics of your implementation, I think you really need to test for yourself (e.g. with a multimeter) how well the motor current sensor output matches your supply current at various duty cycles and loads. If this kind of testing isn’t very practical for you, my suggestion is that you should just go with the current sensor on your power supply.
