The paper discusses the design, simulation, and implementation of a 60W, 115VAC, 60Hz off-grid power inverter. The off-grid inverter creates a mains-level voltage from a 12V lead-acid battery input without connection to a conventional electric grid. The inverter includes a low-voltage H-Bridge circuit that is controlled with 3-level Pulse Width Modulation (PWM), and uses a low frequency step up transformer from 12V to 115V. A feedback system based on IQ sampling and a Proportional, Integral, Derivative controller (PID) is implemented to maintain a constant output voltage amplitude over an input range of 10 to 15VDC. A microcontroller is used to generate PWM and implement the feedback loop. The inverter successfully powers small household loads such as a desktop fan and laptop
