Minimum phase hybrid coupled inductor quadratic boost inverter

Abstract

In this paper, a minimum phase hybrid coupled inductor quadratic boost inverter (QBI) is proposed for DC microgrid applications. Microsources such as solar photovoltaic (PV), fuel cell, wind power, etc. are low voltage generation sources and to meet out the grid requirement a high voltage gain converter is required. Most of the hybrid boost and buck-boost drive inverters found in literature have a right half plane (RHP) zero problems (i.e. non-minimum phase system) and operating range limited to 0.5 duty cycle. With a non-minimum phase control-to-output transfer function, it is hard to obtain adequate phase margin and has bandwidth problems. In the proposed minimum phase hybrid coupled inductor QBI, filter inductors are magnetically coupled and a series damping network is inserted. With this arrangement right half plane (RHP) zero is eliminated for DC boost operation, and thus, the system becomes a minimum phase that provides better dynamic performance. The QBI is capable of giving high step-up voltage gain up to 16-17 times. The proposed minimum phase hybrid coupled inductor QBI provides simultaneous AC and DC outputs with inherent shoot through protection in the inverter stage unlike the conventional voltage source inverter (VSI). A modified pulse width modulation (PWM) technique is also presented for the proposed minimum phase hybrid coupled inductor QBI. The proposed PWM method reduces the stress on the switches and the switching losses of the inverter. Steady state and small signal dynamic modeling are carried out to exhibit the advantages of the proposed hybrid QBI. The concept is validated through simulation and experimental verifications. © 2016 IEEE.