Advantage And Disadvantage Of Inverter

1841 Words8 Pages
INTRODUCTION TO MULTILEVEL INVERTERS An attempt is made to present the most common multilevel (three-level) inverters and briefly describe their advantages and disadvantages based on a literature survey. The literature survey was intended to compare the inverters based on their performance aspects and the challenges and restrictions they could impose for application in the given area. The fundamental purpose of considering multilevel inverters instead of the popular two level inverters is due to the high value of DC-link voltage that needs to be employed in future developments. With increase in DC-link voltage, it is aimed that the performance of the inverter in use does not degrade and hence, multilevel inverter options have been…show more content…
Since the present project concentrates only on the inverter mode of operation of the converter, henceforth, only the term ‘inverter’ will be used. In the case of a multilevel inverter, the DC-link constitutes more than one capacitor bank as opposed to that in a conventional, two-level inverter which consists of only one capacitor bank. The multiple DC sources formed with the series capacitors are aggregated with the commutation of the power semiconductor switches thus giving a high voltage at the output, and at the same time, each semiconductor switch has to withstand only the reduced level of voltage that appears across each capacitor. The connected DC voltage source determines the rating of the power semiconductor switches. It is difficult to connect a single power semiconductor switch directly to high voltage DC-link, as very high voltage rating of the switch has to be chosen by giving allowance to the voltage overshoot due to the stray inductances present in the semiconductor switch and the module (read as a phase leg of the inverter). The number of levels in a multilevel inverter, in effect, can be defined as the number of levels of phase voltage with respect to the negative terminal of the inverter [6]. Therefore, in case of a two-level inverter, the output voltage with two values (levels) is generated with respect to the negative terminal of the capacitor. A…show more content…
The three-phase structure of a Cascaded H-bridge inverter is shown in Figure 1.3. Separate DC sources are connected to each single-phase full-bridge inverter. The AC output of each level is then connected in series such that the overall output voltage waveform of the multilevel inverter is the sum of the individual inverter output [8]. From the knowledge of single-phase full-bridge inverters, each inverter level with Vdc as the DC voltage for each full-bridge can generate three different voltage outputs; +Vdc, 0 and –Vdc and in case of the inverter represented in Figure 1.3, all the levels from -2Vdc to +2Vdc are present constituting 5 levels for the phase. This is made possible by connecting the DC sources (or

More about Advantage And Disadvantage Of Inverter

Open Document