Modeling, control and power quality evaluation of a PEM fuel cell based power supply system for residential use

The use of fuel cell (FC) based power generation system is expected to become more widespread in the near future due to better power quality, reliability, portability and ecological constraints. The use of fuel cell technology for electricity and heat generation for residential-applications generated tremendous interest. Proton exchange membrane fuel cells (PEMPC) are attractive for residential use due to its low operating temperature and fast start up characteristics. This work focuses on the modeling, control (voltage and active power control) and simulation of PEMFC based power supply system for residential applications. A PI type voltage and real power controller is usually implemented by controlling the fuel input into fuel cell stack and adjusting the inverter modulation index. Furthermore, power quality issues are evaluated based on the transformer connection type and harmonic content of the load for household appliances. Detailed simulation software has been developed using the Matlab software package. The topology chosen for the simulation consists of a 5 kW PEMFC, a single stage voltage-sourced PWM inverter followed by an LC filter and a step up transformer. The simulation results illustrate that the voltage at the load point and active power demand versus load variations can be achieved using the PI controller. The control parameters used involves inverter modulation index and phase angle. The power quality evaluation confirms that the bus voltage harmonics meet the IEEE-519 requirements for all home appliances, which are modeled based on real measured values. However, system voltage and current harmonics can be affected either by the harmonic contents of load current or supply voltage overlap at resonance frequency.