EDUCATIONAL AND RESEARCH CONTROL SYSTEM FOR A MULTICELL BATTERY PACK WITH A USER-MODIFIABLE INDUCTIVE BALANCING ALGORITHM

The paper presents the design and investigation of a hardware–software battery management system (BMS) for an eight-cell (8S) lithium iron phosphate (LiFePO4) battery pack with active inductive balancing. Unlike closed-firmware commercial solutions, the proposed system uses a user-modifiable control algorithm on the ATmega328P-MU microcontroller, which allows modifying the cell selection order, switching timing, thresholds and fault response. Cell voltages and the balancing current are measured by INA226AIDGSR devices; power switching is performed by eight channels of back-to-back XR4907/HL4882 MOSFET switches with EL357C optocoupler isolation and a shared inductive storage element. A safe channel-switching algorithm with a 3 ms protective pause and interrupt-driven handling of four fault types with a design-level interrupt-handler response time of up to 10 µs were developed. A prototype PCB was fabricated; transient simulation in Multisim 14.2 with datasheet-based transistor models gives a peak inductor current of 1.13 A and an average balancing current of 370.9 mA over the PWM period, and the effect of the shunt tolerance on the current measurement error was assessed by Monte Carlo analysis. According to the design verification, the cell voltage measurement error after calibration does not exceed ±10 mV, and the balancing current measurement error is ±1.2 % (requirement ±5 %). Telemetry is transmitted via an ESP32-WROOM-32 module over RS-485.