DC-DC Converter Model with Control Strategy Implementation

DC-DC converters are fundamental power electronic devices that transform DC voltage from one level to another. These converters play critical roles in applications such as electric vehicles, renewable energy systems, and industrial power supplies, where stability and dynamic response speed are essential performance metrics.

To optimize performance, a dual-loop control strategy can be implemented, combining an outer voltage loop with an inner current loop. The voltage outer loop regulates the output voltage, maintaining it at the target value. When load variations or input voltage changes occur, the PI (Proportional-Integral) controller in the voltage loop adjusts the current reference value to ensure rapid recovery of the output voltage to its setpoint. In code implementation, this typically involves calculating the voltage error and applying PI control algorithms like: voltage_error = V_ref - V_actual; current_ref = Kp_v * voltage_error + Ki_v * integral(voltage_error).

The current inner loop primarily enhances system dynamic response speed. By continuously monitoring inductor current and employing PI control, the inner loop swiftly adjusts the duty cycle to minimize output voltage overshoot or oscillation. This hierarchical control approach not only improves system robustness but also mitigates adverse effects from sudden load changes or input disturbances. From a programming perspective, this requires real-time current sensing and duty cycle calculation: duty_cycle = Kp_i * current_error + Ki_i * integral(current_error).

The dual-loop control structure is widely applied in DC-DC topologies including Buck, Boost, and Buck-Boost converters, offering balanced output accuracy and dynamic performance. Furthermore, through appropriate tuning of PI parameters using methods like Ziegler-Nichols or automated tuning algorithms, engineers can achieve optimal balance between steady-state error and response speed to meet diverse application requirements.