Hello everyone!

could anybody tell me how can I calculate three phase currents Ia, Ib and Ic, when my drive board is AD-FMCMOTCON2-EBZ?

In the article titled "AD-FMCMOTCON2-EBZ Signal Measurement Chain" (abbr. FMCMOTCON2), there are not any calculation formulas. However, according to the article titled "AD-FMCMOTCON1-EBZ Signal Measurement Chain" (abbr. FMCMOTCON1), some fomulas are introduced. The following one is an example.

But I have some questions for calculating phase currents in FMCMOTCON2:

a) The current measurement method used in borad FMCMOTCON2 has the same principle with Case 1 introduced in the article "FMCMOTCON1". The only difference is the resitance value of shunt resistors. In board FMCMOTCON2, 10mO shunt resistors are used.

Figure 1: Current measurement method in FMCMOTCON1 (here please focus on Case 1)

Figure 2: Current measurement method in FMCMOTCON2

*Can I directly use this calculation formula described in FMCMOTCON1 to calculate three phase currents in board FMCMOTCON2 by setting the value of the parameter "RS" to 10e-3 instead of 6e-3?*

b) The modulator AD7403 is used to sense the differential voltage on the shunt resistor in board FMCMOTCON2. According to the data sheet of AD7403, its output signal is a single-bit data stream and must be digitally filtered by using a sinc3 filter. This is the same for AD7401 used in board FMCMOTCON1. But I can't find any relationship between the formula mentioned before and the sinc3 filter.

*Could you explain it for me in detail?*

In addition, you can find these two mentioned articles under the following links:

*FMCMOTCON1: AD-FMCMOTCON1-EBZ Signal Measurement Chain [Analog Devices Wiki]*

*FMCMOTCON2: AD-FMCMOTCON2-EBZ Signal Measurement Chain [Analog Devices Wiki]*

Thanks,

qxj

The FMCMOTCON2 signal chain wiki page was updated with the equations for computing Ia, Ib and Vbus.

The sinc3 filter converts the single-bit data stream to a 16 bit number. This is reflected in the equations by the term 2^(ADCbits-1)

Regards,

Andrei