Zhan Su, intern of A. Banerjee

Illinois’s Electrical and Computer Engineering Building has sixty 400W solar panels dedicated solely for research. This project aims to create an efficient, reliable, and safe hardware framework to extract power from these solar panels and feed it to the building grid, as shown in Fig. 20

Each solar panel is connected to an isolated dc-to-dc converter that steps up the voltage from 72V (nominal) to 400V (constant). The 400V dc bus takes all the harvested power and delivers it to the grid using two 10KVA inverters. All converters are digitally controlled and connected to a CANbus communication network. Each device’s voltage, temperature, and current are monitored, and each module is controlled remotely through a user terminal. The dc-dc converter comprises two components—a boost converter cascaded with an LLC converter, as shown in Fig. 21. The boost converter controls the power flow using algorithms such as maximum power point tracking, while the LLC converter ensures isolation between the solar panel and the 400V DC bus. The experimental prototype achieves a peak efficiency of 95%. The grid-tied inverter uses using 3-level T-type topology. Compared with a 2-level inverter, this topology has lower switching loss and lower harmonic distortion, reducing the output filter’s size and making the inverter more compact, as shown in Fig. 22

Figure 20: Power architecture to connect sixty research solar panels to the ECE building grid.

Figure 21: Isolated dc-dc converter for each panel

Figure 22: Three-phase grid-tied inverter