H-bridge inverter loading analysis for an Energy Management System

Abstract

The Department of the Navy (DON) is committed to reduce its reliance on fossil fuels. Secretary of the Navy Ray Mabus has said, The underlying reasons for reform are clear. Our energy sources are not secure, we need to be more efficient in energy use, and we emit too much carbon. Microgrids utilizing an Energy Management System (EMS) may be the answer to control and route power more efficiently. The power quality achieved from a single phase pulse-width modulation (PWM) voltage source inverter (VSI) (the heart of an EMS) driving an inductive and capacitive (LC) filter with linear and non-linear loads was investigated in this thesis. The open loop PWM waveforms are compared to the power quality standards for ship board power, MIL-STD-1399-300B. This quantifies the performance limits of open loop PWM, which is the simplest control strategy for a single-phase VSI. Closed loop control is shown to be necessary when larger loads are connected to the VSI in order to prevent output voltage sag.