Quasi Essay

Quasi Z Source Inverter (QZSI) is an efficient topology in recent years due to its unique structure, single stage conversion and continuous input current. These advantages make the researchers to implement the concept particularly with other topologies in the renewable energy field applications like PV as shown in Fig.6. where high input voltage gain is a necessity one[12]. With ease possibility of extending the voltage gain of the input open a way in the distributed power generation field.

Fig. 6. QZSI in PV power generating system

A. Grid Connected PV System

Usually the need for a grid connected inverter is to feed the output from the panels to the grid which is more efficient and with less PQ (power quality) issues. The

In the former control, the inverter is operated in non shoot-through (ST) state with varying SPWM values between 0 ≤ M ≤ 1 and 0 ≤ M ≤ 2∕√3. The latter control utilized Simple boost, Maximum boost & Maximum constant boost control to get maximum voltage gain G which obtained by decreasing the Boost factor B and increases the Modulation index M as possible. Among all these methods, Maximum boost control will be efficient to give minimum voltage stress across the inverter but it introduce low frequency ripple content on the passive elements of the inverter.

III. COMPARSION OF ZSI & QZSI IN VARIOUS RES Z source topology and its improved version Quasi Z source contributes more in Renewable energy systems like solar, wind and Fuel cell in the past two decade. More papers published in dc-dc, ac-dc, and dc-ac conversions along with the concept of qzsi were stated from [14] – [20].

A. Z & QZSI based Fuel Cell

There were no of ways by which an electrical energy is produced, among them Fuel Cell (FC) is a one of the method by which the chemical energy is converted into electrical energy. It is a clean and efficient DC generation source used mainly in vehicles, portable devices and in domestic purpose.

Fig.10. Z source inverter with Fuel