Passivity-based control and Sliding Mode Control of hybrid DC power source applied to Hybrid Electric Vehicles

A Hybrid Electric Vehicle (HEV) is mainly composed of an Internal Combustion Engine (ICE) and an electrical machine. This electrical machine is connected to the DC power sources through an AC/DC inverter and DC/DC converters. Other than being used as a secondary source of the propulsion, this electrical machine together with the other electrical parts, may work as an “active flywheel” to compensate the torque ripples generated by ICE. These ripples are then “transferred” to the DC bus. A hybrid DC power source with battery as the main power and supercapacitor as the auxiliary power is explored in this paper. The DC part is modeled as a hybrid DC power source system with sinusoidal external current. Being different from other works where supercapacitors work as a rapid supplementary power during transient energy delivery or transient energy recovery, the supercapacitor studied here is used to absorb the consistent sinusoidal harmonic in the DC bus. Nonlinear control strategies are employed to achieve the objectives: Passivity-Based Control (PBC) is used to control the battery side bi-direction DC/DC converter to maintain the main power in the DC bus, and Sliding Mode Control (SMC) is applied to control the supercapacitor side bi-direction DC/DC converter to absorb the harmonic.