Tesla Research

This page is about the Turbo-Electric High Energy conversion of the Tesla Model-S Rear Drive Unit which can be bought as salvage on eBay and other places.
It's based around the use of the unit in the Mass-EV electric car project.

The unit was originally bought as a kit from EV-West which included a controller produced by EV-Controls and parts were incrementally upgraded
More details about EV-West/EV-Controls kit here

EVBMW research

The Tesla Project : 15,000 RPM | IGBT Driver | Teardown | It Lives | Logic Board V2 | Back Together | Just Crusin | Thermal Velocity

Others research

lightbulb test | Tesla motor hacked!
Johannes Huebner's Open Source Tesla Controller

Motor Position Encoder

https://en.wikipedia.org/wiki/Incremental_encoder
1002722-00-B CRANKSHAFT POSITION SENSOR
1002722-00-C - SENSOR ENCODER



Found by experimentation that the sensor wheel has 36 teeth:

This is slightly below the stator frequency due to induction motor slip.

Confirmed in a teardown:


Max speed of the motor (according to Tesla) is 18,000 rpm or 300 revs/sec.
Max frequency from sensor is 300 x 36 = 10.8 kHz.


700hp upgrade

The original motor was designed for a 300vDC battery and was down-tuned to limit the power to approx 250kW which is about 800A.
In the Mass-EV project the battery is 33 x 12vDC AGM batteries, which have a rest voltage of 12.6vDC and max 13.8vDC.

This means a pack voltage of between 415v and 455v.
Also the car has 3 packs in parallel each capable of 600A, giving 1,800A

Also the IKW75N60T IGBT array is 16 x 75A (100C rating) for all 6 banks (2 directions by 3 phases).
This is a limit of 1,200A.

Since we are using our own logic board we can unleash the full power of this which is 1.2kA x 455v = 546kW or 732hp.

This is not a sustainable power as things will probably get quite hot very quickly.
With a high power cooling system it will be enough for 10secs of power to get a good standing 1/4 mile.

Also checking Wikipedia figures for torque it looks like it would be in the region of 900 lbft (1,220 Nm).

It's also possible using extreme cooling and series-parallel lithium pack to get even more power.

The IGBTs are capable of 225A and 600vDC each if held at less than 25C.
This would be 16 x 225A = 3,600A, 3600 x 600 = 2,160,000W or 2.16 MW (2897hp),
though I doubt that motor would withstand that for more than a second.

Delving in:

Driver board


Driver board connector





JST CPT connector

+

Driver and output datasheets

1ED020I12FA2 | IKW75N60T

IGBT boards


IGBT board diagram (gates have 10R serial, 2x20R)


Thermister is on the corner IGBT


Connections to the gate driver are mirrored

Tesla Gate Driver Replacement

During testing one of the original driver boards had a fault.
Replacing with another original part was just not an option, they are not available.

This is using a Cree/Wolfspeed CGD15HB62P1 gate driver board as a replacement for the Tesla one.
The CGD15HB62P1 is sold by both RS and Farnell, and probably others, so it's something which is readily available.

It uses the same Infineon 1ED020I12 driver so is compatible with anything which connects to the original Tesla board.
The board plus DC-DC converter comes in under £250 (inc UK VAT).
They are not the right shape to fit in the original space, but there is space above the IGBTs to fit a board so will fit inside the inverter housing.

MANUAL | SCHEMATIC


This board is intended to be used with a Cree IGBT module, so it needs some modification.
The supply is 15vDC instead of 12vDC so needs a DC-DC converter,
also the board is intended to be connected directly to the gates so a connection needs to be added before the on-board gate resistors.




If you are intending to connect the original logic board you will also
need a lead to convert from the JST plug to the Molex socket on the CGD15HB62P1 board,
This would need to include the DC-DC converter inline.




Properly mounted

..with screened leads for the gates

Plenty of space inside sleeve

Trinary control

What is trinary control, and why is it better?
Baically it's shoot-through protection, but details are here


Original gschem schematic

The initial prototype (v1.0) was developed and tested here

Version 2.0

The module was redesigned to be more compact and fit inside inverter housing





This still had issues so the design was adapted further:

Version 3.0

Even more compact plus added sensor and fault inputs:


Original gschem schematic


Original inkscape drawing | mask










Version 4.0

Problems with the space probably contributed to the destruction of the inverter, so version 4 is outside the inverter housing.
This means space is no longer an issue.

Also finally have a mapping to the fault pins:


Amplitude=395 Field=51.3 Shaft=0.0 Slip=100.00% SendWrap=1 Bits=011010101110 ADC=2088 2590 3738 3731 3710 O
Amplitude=395 Field=51.3 Shaft=0.0 Slip=100.00% SendWrap=1 Bits=011010101110 ADC=2088 2590 3738 3731 3710 O
Amplitude=395 Field=51.3 Shaft=0.0 Slip=100.00% SendWrap=1 Bits=011010101110 ADC=2088 2590 3738 3731 3710 O
Amplitude=395 Field=51.3 Shaft=0.0 Slip=100.00% SendWrap=1 Bits=011010101110 ADC=2088 2590 3738 3731 3710 O
Amplitude=395 Field=51.3 Shaft=0.0 Slip=100.00% SendWrap=1 Bits=011010101110 ADC=2088 2590 3738 3731 3710 O
Amplitude=395 Field=51.3 Shaft=0.0 Slip=100.00% SendWrap=1 Bits=011010101110 ADC=2088 2590 3738 3731 3710 O
Short test at roadworthy power:

Here the motor was just spun up rapidly to spike the power draw.

The motor peaked at about 40kw or about 53hp, which is approx the power of a 1.1 ltr piston engine at full power.
Enough to accelerate the car if the wheels were on the ground.

This would also be the sort of power the car would need to maintain motorway speed.

Power testing

Further testing is now being done against the brakes to see how the engine reacts under load.
Here we can see the engine running at over 150A at approx 350v, which is 52.5kw or about 70hp.


To compare this is a Nissan Leaf climbing an approx 9% incline at 30mph.

The Nissan is approx 1.5tons vs approx 4 tons for the prototype.
It's drawing about 20kw so the brake test shows this prototype is capable of doing this.

Cooling system

From shots of the cooling diagnostics, the coolant enters on the motor side and leaves on the inverter side

Just for testing a primitive full sacrificial system is rigged.

Upgraded

Upgraded to radiator cooled system


Added a check for flow rate