Available at: https://digitalcommons.calpoly.edu/theses/3265
Date of Award
6-2026
Degree Name
MS in Electrical Engineering
Department/Program
Electrical Engineering
College
College of Engineering
Advisor
Jason Poon
Advisor Department
Electrical Engineering
Advisor College
College of Engineering
Abstract
This thesis presents the design, implementation, and evaluation of an open-source bidirectional power conversion platform intended for microgrid applications. As distributed energy resources, battery storage systems, and hybrid AC/DC architectures continue to increase in adoption, there is a growing demand for flexible, low-cost, and programmable power electronic platforms capable of interfacing between DC and AC subsystems. Existing commercial solutions are often proprietary and expensive, limiting their accessibility for educational, research, and rapid prototyping applications. This work expands upon the existing open-source Atinverter platform by increasing its operating voltage capability, integrating bidirectional power flow, and implementing telemetry systems suitable for microgrid environments.
The proposed system consists of two primary power stages rated for 100 W operation. The first stage is an isolated bidirectional flyback DC-DC converter designed to convert between a 48 VDC low-voltage bus and a 170 VDC high-voltage bus. The second stage is a bidirectional full-bridge inverter and rectifier capable of converting between a 170 VDC bus and a 120 VAC RMS output at both 50 Hz and 60 Hz operation. The system incorporates integrated AC and DC voltage/current telemetry networks interfaced with an ATMega328P microcontroller to enable future closed-loop control and monitoring applications.
Simulation and experimental testing were conducted to evaluate the operation of both power stages and the sensing networks. Hardware validation demonstrated successful sinusoidal waveform generation at 120 VAC RMS, PWM switching operation and voltage/current sensing with measured telemetry errors generally within 5% of laboratory instrumentation measurements. The inverter stage was experimentally operated across DC input voltages ranging from 12 VDC to 170 VDC and was successfully loaded up to approximately 50 W during laboratory testing. Experimental results iv also identified several practical hardware limitations, including voltage droop under increased loading conditions, and switching-related ringing effects. These findings establish a foundation for future improvements in efficiency optimization, bidirectional operation, and higher-power applications within open-source power electronic platforms.