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DRV8343H-Q1EVM: DRV8343H-Q1EVM

Part Number: DRV8343H-Q1EVM
Other Parts Discussed in Thread: DRV8343-Q1

Dear experts,

I have a question about DRV8343X-QA1EVM Independent Mode User guide @ https://www.ti.com/lit/ug/slvubc2/slvubc2.pdf?ts=1593004899447  

I was very excited about the EVM with the feature of independent FET driving mode. And I wanted to use this evm to drive 3 phase switched reluctance motor as shown in page 6. But I'm confused about the diodes. In the EVM, there is only one diode per phase which is parallel to the coil. But the suitable formation for the switched reluctance motor is two diodes per phase as shown in the figure. 

How can I solve this problem? Thanks.

  • Hi Mustafa,

    Thanks for posting to the MD forum! I apologize for the delayed response. 

    We have an application note on using the DRV8343-Q1 with a Switched Reluctance Motor in Asymmetric Bridge Configuration. See Figure 4 on page 4 to see exactly how to connect the DRV8343-Q1 EVM to use a Switched Reluctance Motor. Make sure you disconnect the 30-A fuses between the SHx-DLx pins to use Independent MOSFET Mode and make the appropriate connections with the recirculation diodes. 

    https://www.ti.com/lit/an/slvaen9/slvaen9.pdf?ts=1596641923225&ref_url=https%253A%252F%252Fwww.google.com%252F

  • Hi Aaron,

    Thanks for the reply.

    The question is; there will be braking energy on the coils since this is an electrical motor. So that might blow up the diodes. 

    Is there any way to connect external freewheeling diodes as shon in my previous post so that that braking energy might be consumed on braking resistors or turn back to the voltage source?

    Thanks in advance.

    Mustafa

  • Hi Mustafa, 

    If you check Figure 4 on the application note link from my previous reply, it is the exact configuration you are looking for from your original post. Freewheeling diodes are configured in order to recirculate current through the diode to the source or through braking resistors. The DRV8343-Q1EVM supports this configuration as shown in the first screenshot below.

    To implement this on the DRV8343Q1-EVM, remove diodes D7-D9 on the top side of the board and populate diodes D10-D15 on the bottom side of the board, and use Independent MOSFET Mode to drive each MOSFET independently for switching on each phase of the SRM. Check the EVM design files if you want to see the schematic of the powerstage (2nd and 3rd screenshot attached below).

  • Thank you Aaron, I got it. Have a nice day.