Research On Cascaded H-bridge Aeronautical Active Power Filter

With the increase of aircraft system capacity and electrical equipment load and complexity,the power quality problem becomes more and more important in the aviation power supply system.Active power filter technology can dynamically compensate the harmonic and reactive components of the load and improve the power quality.Harmonic pollution problem,has been extensively studied and concerned.The cascaded active power filter can compensate the load harmonic current component at low switching frequency and reduce the volume and weight of the interface inductance.In this paper,for the development of high performance aerial active power filter,the active power filter circuit and the control technology are studied.To begin with,different topologies and different control methods of active power filter are introduced.Their advantages and disadvantages are compared,and shunt active power filter is chosen as the research object.In chapter 2,the working principle,control method and the mathematic model of boosting the output frequency of the cascaded bridge arm are analyzed and simulated.Simulation and experimental results are also given to verify the performance of the SPWM inverter with unipolar frequency doubling carrier phase shifting.In chapter 3,several methods of harmonic extraction and direct control of grid current are introduced.Cascaded active filter is modeled by state space averaging method.The parameters of double loop compensation network are optimized and simulated.In chapter 4,we introduce the equalizing loop in the closed-loop control loop of the third chapter to regulate the DC-side capacitor energy equalization of the two cascaded cells,and verify the simulation results..At last,a 1KVA cascaded active power filter prototype is designed and fabricated by cascading two H-bridge circuits.