Modeling and Simulation of Average Current-Mode Controlled Bidirectional Multiphase DC-DC Converters used in Hybrid Vehicles

In this paper, digital Proportional-Integral-Derivative (PID) controller is proposed for DC-DC converter which is employed for energy transfer between 12V battery and 48V battery. The bidirectional DC-DC converter offers energy transfer in both the directions, from 12V battery to 48V battery and vice versa. Multiphase topology of the DC-DC converter supports energy demand of high power(up to 3.3kW) loads, reduces ripples in output voltage thereby reducing filter capacitor value. It also reduces thermal degradation as current is divided in each phase, eventually improves the overall performance and efficiency of the converter. PID controller is used due to its simple implementation, fast computation and good quality of control. Digitalization of the PID controller offers improved response and re-programmability of the control strategy without significant hardware changes. The main function of the controller is to maintain regulated output voltage irrespective of load and input voltage variations. Proposed controller is simulated in MATLAB/Simulink environment in buck and boost mode for varying operating conditions and results are presented in the paper.