Hardware in the Loop (HIL) based Real Time Control of Single-Phase Grid-Connected Inverters

Small power (3 kVA) residential units are typically served by single-phase distribution systems, and single-phase Voltage Source Inverters (VSI) are commonly used to connect photovoltaic panels to single-phase grids. Therefore, the design and control of grid-connected inverters are crucial topics. In this paper, DC-bus voltage control and dq axis-based current control method are applied to a single-phase grid-connected inverter. The T/4 Delay Phase Locked Loop (T/4 Delay PLL) technique is used to obtain phase and frequency information of the grid voltage. Proportional-integral (PI) controllers are designed to control the DC-bus voltage of the system to stabilize power flow. The current control is designed using a PI controller on the dq axes. For real-time experimentation, the Controller-Hardware-in-the-Loop (C-HIL) method is used. The HIL hardware can perform hours of computer simulations in real-time and accurately mimic experimental implementations. As a result, the use of HIL is found to be highly effective in the design of power electronic converters in terms of both hardware and control.