Seven-Level Single Phase Inverter for Multistring PhotoVoltaic Applications

In this research paper seven-level single phase inverter (SLSPI) is designed for Multistring photo-voltaic (MPV) applications. Generally the purpose of inverters with multi-level is to generate quality AC output voltage by reducing the total harmonic distortion (TED) and also it will further decrease the filter dimension. With the help of conventional multi-level inverter, it is possible to increase the number of voltage levels but it leads to increment of inverter components like switching devices, diodes and capacitor and also creates issues on voltage balancing with capacitor. As a result switching loss and pulse width modulation (PWM) control complexity are more as consequence decay the inverter reliability. To cope with these troubles a seven-level 1-φ inverter is presented in this paper. The seven-level inverter (SLSPI) has decreased number of switches as compared to conventional 1-φ seven-level inverter. As a consequence the switching losses, PWM control complexity reduces which improves the reliability. The three separate dc sources required for the proposed topology are easily achievable using multiple PV strings. This makes the proposed topology best suitable for multi string PV applications. The topology also has the advantage of switch and source failure capability. The operation of proposed seven-level single phase inverter using phase disposition carrier PWM is simulated using MATLAB/Simulink.