Five-level cascaded H-bridge inverter for renewable energy applications

Abstract

This paper presents a five-level inverter based on the phase-disposition pulse width modulation (PD-PWM) technique for renewable energy applications. The conventional cascaded H-bridge (CHB) five-level inverter structure is reproduced, and an LC filter is designed to get optimum results from the inverter output. Two batteries are used as renewable energy sources to investigate the performance of the designed inverter. The system can provide 220 volts and 50 Hz AC supply with a 6.9 kW power supply to the load/grid. The designed output is compared with filter and without filter circuit. It provides sinusoidal voltage and current output with a very low total harmonic distortion (THD) of 2.75% which is compliant with IEEE 519 standards. MATLAB/Simulink software tool is used for the entire design. The inverter’s output is graphically represented, and discussed various parameters like switching frequency, THD, modulation index, and rated voltage.

Multilevel inverter: harmonic analysis with and without filters for RL load using SPWM techniques

“…The value of inductance preferred should be below 21% during normal operation [22]. The current ripple can be found as in (1).…”

“…However, solar energy needs other parts in addition to the actual solar cells. In a power system where, alternating current supports the distribution and transmission system, direct current (DC) generating PV systems need inverters to connect their output to the grid; therefore, enhancing the quality of inverters circuits is crucial to surge its efficiency [1]. However, various components involved in designing the inverter such as switching devices to withstand the necessary output voltage involve added hassles and complexity in itself.…”

“…Focus of the optimization proposed in this paper is two folds: improving the quality of output power by shifting the lower order harmonics (3 rd ,5 th ,7 th …) and further improvement with suitable filter circuits. These multilevel inverters are classified as diode/neutral point clamped MLI, flying capacitor MLI, cascaded H-bridge MLI [1]. Among these cascaded H-bridge MLI is considered due to the H-bridge topology with reduced components (such as diodes, capacitor, and Dc link), circuit complexity and equal load sharing among all the switches.…”

“…Due to its modularity the faulty section can be easily identified, replaced, and also easily manufactured. MLI has staircase waveform with improved power quality over the two-level inverter topology, reduced problems of electromagnetic compatibility (EMC) [1], low THD that are suitable for motor drive, solar panel, fuel cells or battery.…”