Wednesday 14 November 2018

SINGLE PHASE INVERTER WITH SIMULATION (MATLAB)

Single phase inverter:

Single phase inverters are used in low power applications like home, office etc. This type of inverter is not use in industries to run heavy load.

There are two types of supplies from utility company; one is single phase supply and other is three phase supply. This type of inverters is use where single-phase utility supply is available. The combination of inverter and battery are used for backup power. In solar power plants, solar energy is generated by PV panels. This power is unregulated DC power. So, this power is not useful, we cannot directly use this power for our home appliances because, this equipment is made for AC supply. So, it requires pure AC supply which is directly not available from PV panels. In this case, the inverters are plays an important role and it is used to convert unregulated DC power in to regulated AC power. This is the main function of inverter.

Operation of single phase inverter:

In single phase inverter, four IGBTs are used for switching. For upper half cycle of sine wave two IGBT (1&4) will operate and for lower half cycle remaining two IGBT (2&3) will operate. By this way, we can get AC waveform across the load. Now, we need gate pulse to ON and OFF IGBT. As we seen, IGBT 1 & 4 operate at same time. So, same gate pulse is required for this both IGBT. Similarly, IGBT 2 & 3 operate at same time. IGBT 1 & 4 operates simultaneously, both switches cannot operate at same time. So, pain 1-4 and 2-3 has exactly opposite gate pulse. This is how we can get square wave AC output. But our appliances are not suitable with this supply. So, we need to convert this square wave output into the pure sine wave output. For that we will use LC filter or LLC filter.

Simulation of single-phase inverter in MATLAB:

Open loop single-phase inverter:

In MATLAB, IGBT/diode is used for switching purpose. The pulse generator is used to generate gate pulse for all IGBT. [A] is gate pulse for IGBT 1-4. [B] is gate pulse for IGBT 2-3. Connect all components as shown in below picture and for more info watch video.