openinverter forum

I am searching for a schematic for the mini mainboard
The previous one had the connections on the file https://openinverter.org/wiki/File:Wiring.png
Specifically how you connect the miniboard with the esp32 interface ?
Which current and voltage sensor you are proposing
thanks

Schematic can be found here: https://github.com/jsphuebner/inverter- ... d-mini.pdf

More info: https://openinverter.org/wiki/Mini_Mainboard

mike72 wrote: ↑Fri Nov 21, 2025 3:41 pm Which current and voltage sensor you are proposing

Depends on the inverter you are using

mike72 wrote: ↑Fri Nov 21, 2025 3:41 pm Specifically how you connect the miniboard with the esp32 interface ?

See the communication section in the schematic. Or via CAN bus.

thanks for the response
The schematic you sent doesnt have the peripherals.
Perhaps because its the same , except the wifi module.
The only connection the ESP32 to the miniboard is the can bus.
Is this the way to connect (canH to canH and canL to canL)

My inverter drives a PMSM motor 236v - 160A max- 3 phase Y - 35kw nominal 50kw limited time - 233 to 800 Hz
It has 3 IGBT semikron SKM400GB07E3
The maximum DC input voltage is 435v and minimum 300v
Do I have to build my own current and voltage sensors based on the https://openinverter.org/wiki/Sense_Boards

The PWM outputs must connect directly to the G1 and E1 of the IGBT or I must use the IGBT driver board ?
thanks

mike72 wrote: ↑Sat Nov 22, 2025 5:48 pm The schematic you sent doesnt have the peripherals.
Perhaps because its the same , except the wifi module.

the Wiki has the answers:

https://openinverter.org/wiki/Mini_Mainboard wrote: Communication
JP1 provides a TTL level (3.3V) UART interface, Pin 3 (RX), Pin 4 (TX)
The communication parameters are fixed to 115200 8N2 (2 stop bits!) and may be raised to 921600.
CAN interface Pin 1 is CANH, Pin 2 is CANL

The ESP connects on the UART RX and TX or CAN. Please use the search function on the forum to find more info on the communication.

mike72 wrote: ↑Sat Nov 22, 2025 5:48 pm Is this the way to connect (canH to canH and canL to canL)

Yes all can_h connect together and all can_l connect together.

mike72 wrote: ↑Sat Nov 22, 2025 5:48 pm The PWM outputs must connect directly to the G1 and E1 of the IGBT or I must use the IGBT driver board ?

YES IGBT drivers are absolutely necessary to drive IGBTs fast enough you need amps of gate current

https://openinverter.org/wiki/Gate_Driver

You can build your own motor inverter, but I would look at a OEM inverter to use.