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The SPI communication is used for the input voltage sense measurements to the MPPTs, indicating the amount power generated by each segment of the array. The SPI communication from the MPPTs will give indication of the input voltage, input current and MPPT temperature as it will internally go into a fault state for an OVP, OCP and OTP conditions.
This validation can be done with the SPI smoke test, and would ideally look at the signal integrity through the isolators and to controller board. But for now, let’s just test for functionality. We will test reading one mppt, and then string two in series.
Populate the following components, we will be testing the channel outlined
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U22, U27, C35, C34, C54, C53, R38, R39, R24, C18, C20, U9, U14, C25, R25, U2, C5, C6, P1
The above components will allow for us to validate the SPI interface. Note, U2 is a decoder that must output the CS to the 6th line for the highlighted channel. For this test, the input of the MPPT must be connected to a power supply and the output to an Eload. Then, the SPI header from the MPPT must be soldered to the spi header on this board. Note; the nomura MPPTs have a trace that must be cut so the SPI header is not all grounded and is useable → see the other validation pages in this space.
We want to make sure we are able to see the MPPT give us information about the voltage, current and temp parameters. To make it accurate to what we expect in the car, use this page to configure the potentiometers on the MPPT (follow the one for the 6 MPPTs): Potentiometer Configuration
Use the following space to record findings:
<insert test table>
Output Voltage sense
Part 2: HV/Series MPPT Testing
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