Description

12S pre-charge controller module for controlled start-up / shut-down behavior of entire system power distribution network.

Engineer: @Robert Tang

Supervisor: @Kevin Li

Requirements

• 12S rated

• Pre-charge/discharge circuit for controlled on/off behavior of entire power distribution network

• Battery voltage / current sense ?

  • 12S

  • 100A pulse current / 60A continuous current

• Dedicated MCU

• CAN interface

System Background/Research

Pre-charge circuits

Open

Why it is needed?

Without the pre-charge circuit, when connecting a high voltage source to the load, which can be modelled as a capacitor, there will be a large potential difference, and this will cause inrush currents that can damage the components. When the pre-charge circuit is used, the load capacitance can be safely charged up, and then the switch can be closed.

Reference documents

Why Pre-Charge Circuits Are Necessary in High Voltage Systems

High-Voltage Solid-State Relay Active Precharge Reference Design Reference design for this TPSI3050-Q1

Managing Inrush Current Not the exact same as pre-charge, but gives an general idea of managing in-rush current, and some of the methods in the doc are relevant to the pre-charge circuit (integrated load switches)

Designing a BCM® Pre-Charge Circuit

https://www.youtube.com/watch?v=dlGTonFXSrI&t=681s

https://github.com/michaelruppe/FSAE/tree/master/Precharge/Precharge Pre-charge circuit for tractive system

Pre-charge Component Selection

Search on DigiKey for: high-side FET driver, not looking for driver with internal FET (can reflect by no R_ds_on in the spec)

IC & Link	Type

IC & Link	Type
TPS4811-Q1 https://www.digikey.ca/en/products/detail/texas-instruments/TPS48111LQDGXRQ1/17748329?s=N4IgTCBcDaIC4AcDOAWAHARiyAugXyA	High Side NMOS Driver	The similar IC (4810) that was used in 12V->5V @ 5A Buck (without pre-charge, 48111 is with pre-charge) 3.5V to 80V input
TPSI3050-Q1 https://www.digikey.ca/en/products/detail/texas-instruments/TPSI3050QDWZRQ1/16982032?utm_adgroup=&utm_source=google&utm_medium=cpc&utm_campaign=Pmax_Shopping_DK%2B%20Supplier_GEM%20Suppliers&utm_term=&utm_content=&utm_id=go_cmp-21018510932_adg-_ad-__dev-c_ext-_prd-_sig-Cj0KCQjwveK4BhD4ARIsAKy6pMJxyw86HCq243F8uFlEpaE6BVITpm026mfZiPFMixVfh7vnSSeOxhEaAmKXEALw_wcB&gad_source=1&gclid=Cj0KCQjwveK4BhD4ARIsAKy6pMJxyw86HCq243F8uFlEpaE6BVITpm026mfZiPFMixVfh7vnSSeOxhEaAmKXEALw_wcB	Isolated Switch Driver	Might be overkill for our application Open
LM5069 https://www.ti.com/product/LM5069?utm_source=google&utm_medium=cpc&utm_campaign=app-lp-null-44700045336317407_prodfolderdynamic-cpc-pf-google-ww_en_int&utm_content=prodfolddynamic&ds_k=DYNAMIC+SEARCH+ADS&DCM=yes&gad_source=1&gclid=Cj0KCQjwveK4BhD4ARIsAKy6pMLj-Di2n2YeonqxwI3qQQAVk8Cjfyq00L2PCqPPIT5Wk05bi75GF08aAlAXEALw_wcB&gclsrc=aw.ds	Current Controller	Is a bit different, does not mention pre-charge directly, but have in-rush current protection and have helped decrease dv/dt
BQ76200 https://www.digikey.ca/en/products/detail/texas-instruments/BQ76200PWR/5801509	High side NMOS Driver	*With PMOS pre-charge FET driver function

CAN (and MCU)

Resources:

CAN - Controller Area Network

ESC CAN Adapter

CAN - Controller Area Network (EFS team)

Current sense

Some pre-charge FET driver IC, such as the TPS48111 chip, has integrated current sensing feature, however I need to do calculations to validate the feasibility of the feature.

If the internal current sensor does not work, an external current sensing circuit is needed

System Design

System Block Diagram: