Submitted by Nathan Lord on Thu, 08/09/2012 - 14:41
The BQ76PL536 is a battery management IC made by TI that allows the team to measure voltages and temperatures of batteries while balancing the batteries with an extra transistor and resister circuit. This chip will be a very fundamental part of our Battery Management System and ECU.
Up to this point in our prototyping, we have been able to use the C2000 experimenter's kits to communicate and control the TI BQ76PL536 Evaluation board. The program can read address all the devices in a stack while reading voltages of each cell connected. The program can also read two temperatures per IC, balance all cells individually, and flash a status LED. This whole program is ran using the RTOS SYS/BIOS provided by TI.
This programming was significantly easier to accomplish than expected because TI provides example code for the Launchpad so I only had to convert that program to work with the C2000 and with SYS/BIOS then it pretty much works perfectly as a driver. The biggest problem with the project is that the CHAR variable type is an 8-bit variable in the Launchpad while it is a 16-bit variable in the C2000 so some of the provided functions had to be changed accordingly.
Pictures on the right show how everything was connected up. You can see we are using batteries connected to a regulator circuit (our cell simulator board) and computer power supply to power up the modules for testing. Later in the project we will do more strenuous testing to make sure the programming keeps the battery packs safe, as a BMS should.