Fault diagnosis in a five-level multilevel inverter using an artificial neural network approach

Abstract

Introduction. Cascaded H-bridge multilevel inverters (CHB-MLI) are becoming increasingly used in applications such as distribution systems, electrical traction systems, high voltage direct conversion systems, and many others. Despite the fact that multilevel inverters contain a large number of control switches, detecting a malfunction takes a significant amount of time. In the fault switch configurations diode included for freewheeling operation during open-fault condition. During short circuit fault conditions are carried out by the fuse, which can reveal the freewheeling current direction. The fault category can be identified independently and also failure of power switches harmed by the functioning and reliability of CHB-MLI. This paper investigates the effects and performance of open and short switching faults of multilevel inverters. Output voltage characteristics of 5 level MLI are frequently determined from distinctive switch faults with modulation index value of 0.85 is used during simulation analysis. In the simulation experiment for the modulation index value of 0.85, one second open and short circuit faults are created for the place of faulty switch. Fault is identified automatically by means of artificial neural network (ANN) technique using sinusoidal pulse width modulation based on distorted total harmonic distortion (THD) and managed by its own. The novelty of the proposed work consists of a fast Fourier transform (FFT) and ANN to identify faulty switch. Purpose. The proposed architecture is to identify faulty switch during open and short failures, which has to be reduced THD and make the system in reliable operation. Methods. The proposed topology is to be design and evaluate using MATLAB/Simulink platform. Results. Using the FFT and ANN approaches, the normal and faulty conditions of the MLI are explored, and the faulty switch is detected based on voltage changing patterns in the output. Practical value. The proposed topology has been very supportive for implementing non-conventional energy sources based multilevel inverter, which is connected to large demand in grid.

Bipolar DC output fed grounded DC-AC converter for photovoltaic application

“…Hence we need to opt for the bipolar DC input structure type inverter. The bipolar inverter likes half bridge inverter, T-type inverter, flying capacitor/capacitorclamped inverter [1]. In this paper we have simulated for T-type inverter.…”

“…Since the output whence the solar PV cell is DC we need to integrate the photovoltaic system with an efficient DC-DC converter topology. The non-isolated topology of DC-DC converter is of copious types [1]. The differentiation of copious DC-DC converter is presented in Table 1, which explains the count of devices used and expression for output voltage along with nature of output whether unipolar or bipolar.…”

“…A. MPPT. The prerequisite of the input current of the converter, which controls the output current of the PV system and hence power, is explained by the P-V and I-V curves [1]. In order to make the maximum power and for the purpose to handle system efficiently and effectively we need to steer the PV panel at its optimum operating point.…”

“…The MPPT controller sends an updated reference value to a PI current controller, which receives it. In most cases, the MPPT's reference would vary smoothly [1].…”

“…The LC filter is been chosen for this purpose.The converter utilizes a decoupling capacitor of 100 µF in order to remove the 100 Hz ripple in the system. A 1 kW F-type inverter has been designed to serve this proposed DC-DC converter[1]. The switching frequency is around 100 kHz, and the rated input voltage is 360 V DC.…”