This solution leverages the STM32G4 microcontroller family for precise digital power management. It addresses industrial automation, renewable energy storage, and telecom infrastructure needs through a robust architecture.

Implementation Details

Hardware Architecture

Microcontroller Unit

The STM32G474RE serves as the central processor:

• ARM Cortex-M4 @ 170 MHz
• 512 KB Flash / 128 KB SRAM
• 5x 12-bit ADC @ 5 MSPS
• 7x Timers with complementary PWM outputs

Power Stage

A synchronous rectifier topology manages bidirectional flow:

• Switches: IPB020N10N3 (100V, 90A)
• Gate Driver: UCC27211A-Q1
• Inductor: IHLP-5050FD-01 (10μH)
• Capacitors: TDK C5750X6S2W225K250KA (2.2μF, 450V)

Sensing & Communication

• Current Sense: INA226 (I2C, 16-bit, ±81.92mV range). Paired with 10mΩ shunt resitsors for ±8.192A measurement.
• CAN: FDCAN controller + TJA1044GT transceivre (5Mbps).
• UART/RS485: MAX3485 for Modbus RTU serial link.
• Display/User: SSD1306 OLED (128x64) + PEC11R rotary encoder.
• Storage: W25Q64JVSSIQ SPI Flash for persistent logs/config.
• Thermal: MAX31855KASA+ thermocouple interface (K-type, 14-bit).

Software Architecture

The firmware runs on ChibiOS/RT, organized into hierarchical layers.

Task Configuration

Control Algorithms

PID Engine

Implements standard discrete PID with anti-windup protection.

typedef struct {
    float kp, ki, kd;             // Gains
    float integral_accumulator;   // Sum of errors
    float previous_error;         // For derivative term
    float out_min, out_max;       // Actuator limits
} control_loop_t;

float control_tick(control_loop_t* ctx, float target, float measured) {
    float err = target - measured;

    // Integral accumulation with saturation
    ctx->integral_accumulator += err;
    ctx->integral_accumulator = fmaxf(ctx->out_min, fminf(ctx->integral_accumulator, ctx->out_max));
    
    float I = ctx->ki * ctx->integral_accumulator;
    float D = ctx->kd * (err - ctx->previous_error);
    ctx->previous_error = err;

    float result = (ctx->kp * err) + I + D;
    return fmaxf(ctx->out_min, fminf(result, ctx->out_max));
}

Adaptive Tuning

Adjusts gain dynamically based on error magnitude.

void adaptive_gain(control_loop_t* ctx, float current_err) {
    float abs_err = fabsf(current_err);
    
    if (abs_err > 5.0f) {
        ctx->kp *= 1.1f; 
    } else if (abs_err < 1.0f) {
        ctx->kp *= 0.9f; 
    }
    
    // Clamp Kp to safe bounds
    ctx->kp = fmaxf(0.1f, fminf(ctx->kp, 10.0f));
}

Soft Start Sequence

Prevents inrush current during initialization.

typedef struct {
    float ramp_target;
    float ramp_current;
    float rate_per_sec;
    uint32_t start_timestamp;
} soft_start_context_t;

float soft_start_step(soft_start_context_t* ss, uint32_t current_tick_ms) {
    if (ss->start_timestamp == 0) {
        ss->start_timestamp = current_tick_ms;
        ss->ramp_current = 0.0f;
    }

    uint32_t elapsed_ms = current_tick_ms - ss->start_timestamp;
    float elapsed_s = elapsed_ms / 1000.0f;
    
    ss->ramp_current += ss->rate_per_sec * elapsed_s;

    if (ss->ramp_current >= ss->ramp_target) {
        return ss->ramp_target; // Ready
    }
    return ss->ramp_current;
}

Power Factor Correction

Manages reactive power by adjusting duty cycles.

typedef struct {
    float last_v_rms;
    float last_i_rms;
    float calculated_pf;
    float pwm_duty;
    float desired_pf;
} pfc_manager_t;

void pfc_adjust(pfc_manager_t* manager, float v_sample, float i_sample) {
    // EMA for RMS estimation
    manager->last_v_rms = (manager->last_v_rms * 0.9f) + (fabsf(v_sample) * 0.1f);
    manager->last_i_rms = (manager->last_i_rms * 0.9f) + (fabsf(i_sample) * 0.1f);

    // Simplified PF calculation (Active / Apparent)
    float apparent = manager->last_v_rms * manager->last_i_rms;
    float active = v_sample * i_sample;
    
    if (apparent > 0.001f) {
        manager->calculated_pf = active / apparent;
    }

    float diff = manager->desired_pf - manager->calculated_pf;
    manager->pwm_duty += diff * 0.01f;

    manager->pwm_duty = fmaxf(0.1f, fminf(manager->pwm_duty, 0.9f));
}

float pfc_get_output(const pfc_manager_t* manager) {
    return manager->pwm_duty;
}

Deployment & Maintenance

Flash Programming

Supports remote update protocols.

bool flash_upgrade(uint8_t* image_buffer, size_t img_size) {
    image_header* hdr = (image_header*)image_buffer;
    
    // Verify integrity
    if (calc_crc32(image_buffer + sizeof(image_header), img_size) != hdr->checksum) {
        return false;
    }

    // Erase sector
    FLASH_LockSector(hdr->address);

    // Write block
    FLASH_WriteBuffer(hdr->address, image_buffer + sizeof(image_header), hdr->size);

    // Confirm write
    if (!FLASH_Verify(hdr->address, img_size)) {
        return false;
    }

    SetBootFlag(hdr->version_id);
    return true;
}

Validation Strategy

Automated testing covers edge cases and timing constraints.

// Verification Example
TEST(void) test_power_loop_stability() {
    control_loop_t pid = {1.0f, 0.1f, 0.01f, 0, 0, -50.0f, 50.0f};
    
    // Step response simulation
    float val = control_tick(&pid, 12.0f, 5.0f);
    TEST_ASSERT_FLOAT_EQUAL_WITHIN_TOLERANCE(50.0f, val, 0.1f);
}

void run_system_stress_test() {
    init_hardware();
    wait_voltage_settle(12.0f, TIMEOUT_MS);
    
    assert_near(get_power_factor(), 0.98f, 0.05f);
    confirm_comm_channels(CAN | MODBUS);
}

Compliance Checks

Systems undergo rigorous electromagnetic compatibility screening, including conducted emission (CISPR 22) and immunity tests against electrostatic discharge (ESD).