This chapter presents a three-cell flying capacitor converter photovoltaic (PV) system. This system consists of a DC-DC boost power converter connected in series with a multicell inverter. The perturb and observe MPPT technique has been used to extract the maximum power from the solar panel and generate the duty signal to control the switch of the DC-DC converter. The three-cell flying capacitor inverter ensures the conversion of the output voltage of the boost chopper to the alternative voltage. This topology is made up of hybrid association of commutation cells, which makes it possible to share the voltage constraint on several switches. A closed loop control based on PWM has been proposed to control the capacitor voltages of the inverter. The output current is controlled using a PI regulator. The aim of the proposed three cell inverter is to produce an approximate sinusoidal output current with a very low THD. The simulation results assess the effectiveness of the control.
TopIntroduction
Renewable energy sources have arisen as a realistic alternative to significantly reduce carbon emissions and limit the rate of global warming (Ameur et al., 2018). The major drawbacks of renewable energies reside in its changing conditions, abundance in the region, and cost. The choice of one source or more, to meet the system requirement, depends on these criteria. Among the various sustainable energy sources, solar energy is the most elegant with zero emissions (Knez & Jereb, 2013).
For both domestic and industrial users, it has become a popular source of electricity (Knez & Jereb, 2013). This includes different applications for solar electric cars, charging stations for vehicles, a significant range of water pumping systems and stand-alone systems for places where there is a lack of reliable access to the grid (Hassan et al., 2017).
Photovoltaic power generation contains solar PV panels, where a DC-DC converter supplies the output of a solar panel to the DC connection. The voltage from the DC connection is supplied to the DC-AC inverter and is supplied to the load(Amara et al., 2018). The performance of the solar PV is not constant and varies according to the temperature and solar irradiation(Mosa et al., 2017).
Therefore, even under varying climatic changes, optimum power must be derived from the PV module for the efficient operation of the PV panel. To achieve these goals, the maximum power point tracking (MPPT) based techniques are used to extract the maximum power from the panel using a DC-DC converter (Manna & Akella, 2021). The use of MPPT in the PV system improves the solar module's performance and life span (Bahgat et al., 2005). Before connecting a PV system to the AC load, the output voltage of the solar modules must be converted into an AC voltage, hence the need to introduce a DC-AC converter (Ciobotaru et al., 2006).
Nowadays, using low voltage strength semiconductors, we can synthesize high voltage multilevel waveforms(Othman et al., 2020). This discipline affects many areas of use, ranging from a few Watts to several hundred megawatts, such as electrical machine control (Hamida et al., 2019), railway traction (Guo et al., 2019), high voltage direct current HVDC electrical energy transport (Bakas et al., 2020) and parallel active filtering (Rao et al., 2020).
Harmonics, which are the source of tension wave distortion, circulating in non-linear loads such as motors, induce circulating currents in conducting torque decreasing materials, when exposed to a variable magnetic flux. The International Electrotechnical Commission (IEC) specifies the measurement of appropriate values and methods of correction (Fujita et al., 1998). In order to limit the rate of harmonic disturbance, a variety of methods to reduce harmonics have been suggested, which are based on passive or active filters (Green & Marks, 2005; Marzouki et al., 2015). Power electronic solution is one of these reduction methods. It has shown a very important technological development: PWM rectifiers (Fekik et al., 2015; Fekik et al., 2016; Fekik et al., 2017 ; Fekik et al., 2018; Fekik et al., 2019 ; Fekik et al., 2021). This is accomplished by the development of semiconductors, power components and new energy conversion systems (Kesarwani & Stauth, 2015; Rajagopal et al., 2019). Flying capacitor inverters occur among these systems (Escalante & Erdmann, 2021).
The flying capacitor converter structure is relatively recent, it was introduced at the beginning of the 1990’s (Meynard, Foch, Thomas, et al., 2002), this topology has acquired a fundamental interest in the high-energy systems (Meynard, Foch, Forest, et al., 2002). This topology ensures equal stress distribution on the different low voltage semiconductor devices connected in series and improves the output waveforms and harmonic content when an adequate phase control strategy is applied (Boulouiha et al., 2019).