Diode-clamped Multilevel Inverters

today, variable speed pumped storage (VSPS)
system is an emerging technique, being used in hydro powered
plants to increase the efficiency, quality and control of the power
of the grid. The doubly fed induction machine (DFIM) based
VSPS systems are gaining more importance because of the cheap
price of the converter i.e. back to back power electronics
converter. This paper discuses an efficient method for the rotor
side converter (RSC) to control the active and reactive power
flowing through the stator of DFIM while the grid side converter
(GSC) has been used to maintain the DC voltage level. This paper
also discusses the VSPS systems Worldwide and its comparison
with hydro powered projects which are recently developed in
Pakistan. This paper suggests the use of VSPS systems in
Pakistan to increase the efficiency of the conventional hydro
power projects.

For application of PV systems, a major deterrent factor in their use is high initial investment. A focus has therefore been placed on new, cheap and innovative inverter solutions. As a result of this, a single stage inverter topology and a new configuration are proposed. In two stage circuit, the first stage takes care of MPPT and boosting the PV voltage while second stage inverts the first stage output into the required AC form. A two stage configuration has drawbacks such as high part count, lower efficiency, lower reliability, high cost and large size. These drawbacks are overcome by the circuit proposed in this paper. The new inverter circuit proposed in this paper is designed and simulated in a simulation environment. The improved topology increases the voltage, reduces the power loss and enhances the various electrical parameters. This enhancement and improvement of electrical quantities is explained with the help of different formulae and figures. With the use of this improve circuitry; the efficiency of the PV Array can be increased. The proposed inverter design and its implementation are given with operational results. Keywords — Inverters, Boost inverter, DC-AC Converter, power semiconductor switches. I. INTRODUCTION Due to the increase in industrial revolution, the world energy demand has also increased. Photovoltaic (PV) system has taken a great attention since it appears to be one of the most promising renewable energy sources. the PV solar generation is preferred over the other renewable energy sources due to the advantages such as absence of fuel cost, cleanliness, pollution free and little maintenance. Solar inverter is a critical component in a solar energy system. It converts DC power output into AC that can be fed into the grid and directly influences the efficiency and reliability of solar energy system. Grid connected PV systems have become very popular because they do not need battery backups to ensure MPPT. The grid can absorb any amount of power and so the maximum utilization of the available solar power is ensured. In this grid connected PV system, the inverter is the heart of the system which is responsible for converting DC power into the required AC power.