Solar hybrid inverter is one device that combines the benefits of the traditional solar inverter with battery power conversion system. This process allows users to have more alternatives for cleaner power production, storage and use. Hybrid inverter is not only designed to connect multiple PV strings and convert the DC to AC, but also support DC directly to Battery Energy Storage System (BESS). By integrating the battery power conversion system, for example, bi-directional DC-DC converter, hybrid inverters eliminate unnecessary DC to AC power conversion through DC BUS coupling and thus reduce losses.

Hybrid inverter mainly targets residential and small commercial-industrial application scenarios. The power level of single-phase hybrid inverter is usually less than 10KW. The power level of 3-phase hybrid inverter usually ranges from several KWs to dozens of KWs. Figure 2-5 shows the typical 3-phase hybrid inverter block diagram with Hall-effect Current Sensors, and so on.

• String current sampling.
• Arc current detection (optional).
• MPPT Boost current sampling.
• Inverter 3-phase current sampling.
• Bi-directional Converter (BDC) current sampling.
• Off-grid Emergency Power supply (EPS) 3-phase current sampling.
• Neutral current sampling for midpoint potential balancing.

Compared to above string inverter or residential inverter, hybrid inverter has more hall-effect current sensors because of ESS and off-grid EPS functions. In addition, for the market where power cut occurs frequently, such as in Africa, hybrid inverter also supports acquiring energy from diesel generator. There has extra off-grid 3-phase current sampling of the diesel generator port.

Figure 2-5 3-phase Hybrid Inverter Block Diagram with Hall-effect Current Sensors