Question about MC9S12ZVML128_PMSM_Sensorless_SingleShunt(AN5327)

[leeuram]

Hi all!

I'v got AN5327 source code and It is working well at NXP EVB.

NXP EVB current sensing AMP0 circuit (below Low side FETs) has 2.5v reference offset.

But my own board don't have 2.5v reference offset circuit. only can measure one direction current flow.

[Question]

How can I work AN5327 at my own board(no 2.5 offset voltage)?

Is it possible to source code modification?

Best regards.

[pachamatej]

Hello,

I'm afraid that without this 2.5V reference (offset) your board is not compatible with the AN5327. Please understand that in FOC, both positive and negative currents flow through the DC-link shunt resistor and both polarities are needed for the current reconstruction. The current reconstruction will not work with such limited input information.

I'm not saying that it is not possible to control a PMSM using your HW at all. However, you would need to use different techniques and even lower your performance expectations to achieve this. This is way beyond the scope of any software example and this forum. From my perspective, it is much easier to do a HW revision and to add this 2.5V reference - it can be done also using a voltage divider from 5 V level.

Best regards,

Matej