17-09-2009, 02:00 AM
INTELLIGENT BATTERY CHARGING USING PIC16F73 MICRO CONTROLLER FOR MISSILE TEST EQUIPMENT.
It is designed and developed based on microprocessor technology for Konkurs Missile Test Equipment (KMTE) assembled on a PCB module mounted on a bracket, in turn to be fitted on front panel PCB frame of test equipment.
Charger is intended to charge Ni-Cd/Ni-Al battery pack capacity of 1.8AH/2.2AH respectively. It shall operate on AC mains power of 230V AC at 50Hz with specified variation. The regulated power supply of charger works on SMPS and converts incoming AC voltages to DC(maximum 60V) for charging the battery. Charging is done in two modes. Normal mode and boost mode. At the end of normal/boost charge, the charges automatically charge over to the trickle mode. Mode of changing is switch selectable and the charging mode can be indicated LEDs which are connected on D-type connector.
The charge is based on a PIC16F73 micro controller. The micro controller provides desired features of time tracking, detection of negative voltage shift to monitor the charging process. The input AC voltage is passed through the input fuse and line filter, followed by bridge rectifier. The resultant DC voltage is fed to the transformer with the separate taps for charger circuit and micro controller circuit. Output of the charge is maintained at nominal voltage of 60V DC. Required sense lines and control lines are provided between the charger circuit and microprocessor circuit. The status of charging is detected using micro controller provision is available for selection of normal boost charge. LED can be connected to the connector for charge indicator. Selection provision shall also be made for selection in battery type.
On power ON, the AC current passes through the fuse and the filter, this filter out any noise or spikes. After the filter passes through the rectifier which converts AC to DC. Next to rectifier it passes through the transformer and provides a constant voltage to the charger. Past of the winding from transformer is taken TOP switch to generate supply. The micro controller reads the input current voltage input coming from the batter and Vref generated in the circuit. The controller generates the current reference voltage to current loop circuit by reading the inputs and adjusting the PWM in the controller according to the inputs taken.
The project involves both hardware and software. The primary component used in the project i.e., PIC16F73 Microcontroller. has to be studied and tested. The other components are available in discrete. These components are to be assembled on the PCB board and then proper connections are to be made. Coded microcontroller i.e., PIC16F73 has to be used in order to perform the charging operation by connecting the PCB module to the system using RS-232 cable
