Single-phase Five-level Boost Inverter for Stand-alone PV Applications

This paper proposes a single-phase five-level boost inverter (SFBI) with twelve switches and a flying capacitor (FC) to boost the output voltage. SFBI can produce peak output voltage up to double the DC-input voltage. Hence, a dc-dc boost converter may not require in a stand-alone PV system. SFBI has advantages such as low FC requirement, equal voltage stress and sensorless operation. Also, it does not require any of the bulky inductors/capacitors, multiple voltage sources/transformers. A sophisticated capacitor voltage balancing algorithm is not required to produce balanced five-level boost voltage due to self-balancing of FC voltage in every switching cycle. SFBI is explained in detail using various operating modes and compared with other multilevel inverters to elevate its advantages. The SFBI is implemented in PSCAD/EMTDC and steady-state results are presented to verify its operation.