BMW i3 Inverter

BMW I3 inverter

BMW I3 inverter

Forum thread: https://openinverter.org/forum/viewtopic.php?p=23214#p23214

BMW i3™ inverter drop-in board Available

https://openinverter.org/shop/index.php?route=product/product&product_id=72

Pinout for Ampseal Plug

Pin No	Assigniment	Description
1	12V
2	BRAKE_IN
3	PRECHARGE_OUT
4	CANL
5	CANH
6	DCSW_OUT
7	FORWARD_IN
8	REVERSE_IN
9	5V (OUT)
10	RESOLVER_S2/ENCODER_A	Sin Hi
11	GND
12	RESOLVER_S1	Sin Lo
13	THROTTLE1
14	THROTTLE2
15	RESOLVER_R1	Ex Hi
16	RESOLVER_S3/ENCODER_B	Cos Hi
17	MTEMP+
18	MTEMP-
19	RESOLVER_S4	Cos Lo
20	EMCYSTOP_IN
21	GND
22	RESOLVER_R2	Ex Lo
23	START_IN

There are 2 variants of the i3. one with the REX and one with out.

the REX variant has a additional 25kw inverter to run the onboard generator.

Power stage: Infineon FS800R07 IGBTs rated for 800amps 650v

Gate Driver Board

Gate Driver Board Pin out

Pin No	I/O	Description	Notes		Pin No	I/O	Description	Notes
1					21		GND Switching Mosfets ?
2	I	32V in			22		GND Switching Mosfets ?
3	I	32V in			23
4	I	IGBT A HI			24
5	I	IGBT A LOW			25
6	I	CS (ADC)			26		GND IGBT Driver ground
7	I	SDI			27		GND IGBT Driver ground
8	I	SDO			28		GND IGBT Driver ground
9	I	SCK			29		GND IGBT Driver ground
10	I	IGBT B HI			30		GND IGBT Driver ground
11	I	IGBT B LOW			31		GND IGBT Driver ground
12	I	IGBT C HI			32		GND IGBT Driver ground
13	I	IGBT C LOW			33		5V IGBT Driver Power
14					34		5V IGBT Driver Power
15					35	I	IGBT PSU 12V on
16	O	IGBT DRIVER UVW Upper Ready			36	O	IGBT Driver Fault
17	O	IGBT DRIVER UVW Lower Ready			37	I	5V LEM Current sensor Power
18	O	Current Sense C Signal			38		GND Current sensor Ground
19	O	Current Sense B Signal			39		GND Current sensor Ground
20	O	Current Sense A Signal			40		GND Current sensor Ground

Gate Driver Board - SPI Commication

The BMW gate driver board communicates the DC bus voltage (ie traction battery voltage) and IGBT heatsink temperatures to the Openinverter via SPI.

On the Openinverter mini mainboard, pin 17 on JP2 is used for the SPI Clock signal, instead of its default assignment as 'Error Output'.

To avoid the clock signal being pulled high or low by the pin acting as an Error Output, find this section of code in vehiclecontrol.cpp:

//Brake pin is used as SPI_MISO
DigIo::brk_out.Configure(GPIOC, GPIO5, PinMode::INPUT_FLT);

and insert this below it to disable the Error Output:

//Disable err_out so it doesn't pull the clock signal up or down
DigIo::err_out.Configure(GPIOC, GPIO10, PinMode::INPUT_FLT);

Motor Resolver & Temperature Sensors

12-pin PCB header to connect to the motor sensors is an ERNI MiniBridge, part number 294920

Suspected wire colours to pin allocation below determined by schematic and multimeter trace, with resolver coils and temperature sensors checked for resistance.

Note as of 03 December 2023 this pinout has only been checked by manually rotating motor, but not under powered operation.

ERNI Minibridge Connector. Dots indicate pin 1.

Pinout for ERNI Microbridge

Pin No	Colour	Description	Notes
1	Brown	Sin Hi	Twisted pair. 22.4 - 33.6 Ω.
2	Blue	Sin Lo
3	Yellow	Ex Hi	Twisted pair. 22.4 - 33.6 Ω
4	Green	Ex Lo
5	Red	Cos Hi	Twisted pair. 13.6 - 20.4 Ω
6	White	Cos Lo
7	Blue	Temperature Sensor	From BMW Service Technical Training Manual - I01 High-voltage Components: There are two stator coil temperature sensors. The rotor temperature is determined using readings from the stator temperature sensors.
8	Grey
9	Red	Temperature Sensor
10	Grey
11	-	Unused	These wires terminate in one of the six pin connectors in the motor housing. There is nothing connected to them.
12	-	Unused