Solar energy is an important part of a DC microgrid, with the main goals to save energy costs and reduce dependency on the AC power grid. A dedicated power converter conditions the variable voltage from the solar panels to a stable DC link voltage.

TI’s 10kW gallium nitride (GaN)-based reference design was originally designed as a string inverter with battery energy storage system (BESS) capability. While it features three main stages, only two are essential for a DC microgrid application.

The input boost stage converts the solar panel voltage (50V to 500V, from two to 10 photovoltaic cells) to a defined DC link voltage. This output voltage can either directly power the microgrid or is adjustable to a different voltage level through a downstream DC/DC converter stage.

The bidirectional DC/DC converter stage manages the BESS by efficiently charging and discharging the battery. It ensures smooth energy flow to and from the battery, maintaining grid stability and supporting energy storage needs.

The third stage of the design consists of a configurable bidirectional DC/AC converter. In a PFC configuration, it takes power from the AC grid to the DC link to charge the BESS. In an inverter configuration, it converts the power from the BESS or the solar panels and feeds energy back to the AC grid (see Figure 4-1).