EVSPIN32G4 Motor Current Sensing

[LPort.2]

Hello,

Here are a few things I need to clarify regarding the EVSPIN32G4 current measurement and the related MCSDK software:

Referring to section 5.6.1, 5.6.2 and 5.6.3 of the UM2850, I believe that the topology using three standalone OpAmps presented in section 5.6.2 is not currently supported by MCSDK, is this correct?

So, considering the 2 topologies presented in 5.6.1 and 5.6.3, is there a major disadvantage to go for the internal PGA solution compared to the first configuration which requires external feedback networks on the inverting side of the OpAmp?

At the end of section 5.6.3, it is recommended to connect the inverting input of the PGAs to shunt resistors to perform differential current measurement in case of high current application, but I don't have the possibility to do it in MCSDK since only the "single ended" sensing type is available, what do you propose in this case?

Thanks in advance and best regards.

[Cristiana SCARAMEL · Accepted solution]

Hi @LPort.2​ and welcome to the ST Community.

You are right, the STM32 MC SDK does not currently support this sensing topology.

The major drawback, as you noted, is that you cannot actually perform differential current sensing. The user manual of the EVSPIN32G4 UM2850 will be fixed in section 5.6.3.

For high current applications we definitely recommend using the default topology with OPAMPs in stand-alone mode and external resistors.

I hope this post can help you; if so, consider to mark it as best answer by clicking the label "Select as Best".

[JKolj.1]

Is this something you are planning to support in an upcoming MCSDK release? We need this for our current project, and we are currently considering developing it ourselves unless the june/july MCSDK ships with out of the box support.​

[Cristiana SCARAMEL]

Hello @JKolj.1​,

integration of this topology is currently not in roadmap.

[JKolj.1]

So let me get this straight, you have built a three standalone opamp feature in a dev kit, and I think we all agree that it's superior (differential measurement, and actually HW LPF as well), but you have no plans to support it? Why is that?

[LPort.2]

Hi Cristiana,

Thanks for your reply.

Currently, the PGA or the 2 op-amps and multiplexer configurations do not support differential current sensing but are supported by MCSDK, so no software features supports differential current sensing at the moment?

I really like the STSPIN32G4 solution you have developed and consider it as very promising for integration and component cost reduction, but full software support from your side would of course be appreciated.

[GuiOtt]

Ok, acknowledged that there is no way to be wizarded with MC Workbench on configuring Evspin32G4 in differential mode OpAmps (as strongly recommended), I started on configuring it directly with CubeMX, according to the schematics.

The configuration is for three shunts, differential mode current sensing with current protection: 3 opamps, three comparators, external gain setting.

Opamps OUT 1, 2 and 3 are routed to ADC1 IN3 , ADC2 IN3 and ADC1 IN12. it's not possibile to use ADC1 IN1 as described in UM2850 5.6.2. 

I would like to share my configuration if it can be useful but, could someone please double check that to confirm correctness? 
Thanks in advance for attention