Comprehensive Control Strategy and Verification for PEM Fuel Cell/Battery/Supercapacitor Hybrid Power Source

Using renewable energy is becoming a new tendency for vehicular applications to reduce fossil fuel consumption and minimize greenhouse gas emissions. Well-known as an eco-friendly energy source, the proton exchange membrane fuel cell (PEMFC) is extensively used in hybrid power systems to achieve the objective of zero-emission and air protection. However, this type of fuel cell offers slow dynamics and cannot adapt to abrupt load variations when used as a primary energy source. To overcome this shortcoming, battery (BAT) and/or supercapacitor (SC) are supplemented as auxiliary sources. In this paper, an innovative energy management strategy (EMS) for a PEMFC/BAT/SC hybrid power source (HPS) is proposed to improve the accuracy of power distribution from energy sources to the load. In detail, according to different characteristics of energy sources, a frequency decoupling (FD) method is designed to determine the required currents for PEMFC, BAT, and SC based on the load power demand. Besides, an adaptive DC bus control loop is utilized to guarantee a stable DC output voltage by using the BAT. The proposed EMS is simulated in a MATLAB/Simulink environment and experimentally implemented with a real-time DSP TMS320F28379D controller board. Subsequently, a test bench of a 200 W PEMFC, 24 V-12 Ah battery, and 25 V-60 F supercapacitor is conducted for experimental validation. The obtained results show that the proposed EMS is effective to coordinate energy flows between the three used sources and enhance the fuel cell performance in a hybrid power system.