Hiralal M. Suryawanshi

Adaptive Neural Fuzzy Inference System for the Detection of Inter-Turn Insulation and Bearing Wear Faults in Induction Motor

The positive features of neural networks and fuzzy logic are combined together for the detection of stator inter-turn insulation and bearing wear faults in single-phase induction motor. The adaptive neural fuzzy inference systems (ANFISs) are developed for the detection of these two faults. These faults are created experimentally on a single-phase induction motor in the laboratory. The experimental data is generated for the five measurable parameters, viz, motor intakes current, speed, winding temperature, bearing temperature, and the noise of the machine. Earlier, the ANFIS fault detectors are trained for the two input parameters, i.e., speed and current, and the performance is tested. Later, the three remaining parameters are added and the five input ANFIS fault detector is trained and tested. It observed from the simulation results that the five input parameter system predicts more accurate results

Unity-Power-Factor Operation of Three-Phase AC–DC Soft Switched Converter Based On Boost Active Clamp Topology in Modular Approach

In this paper, a three-phase ac-dc converter using three single-phase pulse width modulated active clamped, zero-voltage-switched boost converter in modular approach is presented. The active clamp technique is used for zero-voltage-switching of the main and auxiliary switches. The operating modes, analysis, and design considerations for the proposed converter are explained. To evaluate the performance of the proposed converter, finally simulation and experimental results for a 500-V, 1.5-kW prototype converter are presented. The proposed converter operates at almost unity power factor with reduced output filter size. The output voltage is regulated without affecting zero-voltage-switching, even under unbalanced three-phase input voltages.

Three-Dimensional Space-Vector Modulation to Reduce Common-Mode Voltage for Multilevel Inverter

In this paper, an approach to reduce common-mode voltage (CMV) at the output of multilevel inverter using 3-D space-vector modulation (SVM) is proposed. The 3-D SVM is superset of the traditional 2-D SVM, and thus, it inherits all the merits of traditional 2-D. A simple technique for the selection of switching states to constitute the reference vector is proposed here. The computational cost of the proposed technique is independent of voltage levels of inverter. This technique is easy to implement online in digital controller. The tradeoff between quality of output voltage and CMV is achieved in this paper. This paper realizes the implementation of 3-D SVM to reduce the CMV using a five-level diode-clamped inverter for a three-phase induction motor. Experimental and simulation results demonstrate the feasibility of the proposed technique.

Soft-Switching DC–DC Converter for Distributed Energy Sources With High Step-Up Voltage Capability

This paper presents high step-up dc-to-dc converter for low voltage sources such as solar photovoltaics, fuel cells, and battery banks. To achieve high voltage gain without large duty cycle operation, combination of coupled inductor and switched capacitor voltage doubler cells are used. By incorporating active clamp circuit, voltage spike due to the leakage inductance of the coupled inductor is alleviated and zero-voltage switching turn on of the main and auxiliary switch is obtained. Due to the use of MOSFETs of low voltage rating and soft turn on of the switches, conduction loss and switching losses are reduced. This improves the efficiency and power density of the converter. The proposed converter can achieve high voltage gain with reduced voltage stress on MOSFET switches and output diodes. Design and analysis of the proposed converter is carried out, and finally, a 500-W experimental prototype is built to verify theoretical analysis.

A Three-Phase Hybrid Cascaded Modular Multilevel Inverter for Renewable Energy Environment

This paper presents a three-phase hybrid cascaded modular multilevel inverter topology which is derived from the proposed modified H-bridge module. This topology results in the reduction of number of power switches, losses, installation area, voltage stress and converter cost. For renewable energy environment such as photovoltaic (PV) connected to the microgrid system, it enables the tranformerless operation and enhances the power quality. This multilevel inverter is an effective and efficient power electronic interface strategy for renewable energy systems. The basic operation of single module and the proposed cascaded hybrid topology is explained. The ability to operate in both symmetrical and asymmetrical modes is analyzed. The comparative analysis is done with classical cascaded H-bridge and flying capacitor multilevel inverters. The nearest level control method is employed to generate the gating signals for the power semiconductor switches. To verify the applicability and performance of the proposed structure in PV renewable energy environment, simulation results are carried out by MATLAB/Simulink under both steady-state and dynamic conditions. Experimental results are presented to validate the simulation results.

Multilevel Inverter to Reduce Common Mode Voltage in AC Motor Drives Using SPWM Technique

In this paper, an approach to reduce common-mode voltage (CMV) at the output of multilevel inverters using a phase opposition disposed (POD) sinusoidal pulse width modulation (SPWM) technique is proposed. The SPWM technique does not require computations therefore, this technique is easy to implement on-line in digital controllers. A good tradeoff between the quality of the output voltage and the magnitude of the CMV is achieved in this paper. This paper realizes the implementation of a POD-SPWM technique to reduce CMV using a five-level diode clamped inverter for a three phase induction motor. Experimental and simulation results demonstrate the feasibility of the proposed technique.

High Power Factor Operation of a Three-Phase Rectifier for an Adjustable-Speed Drive

This paper presents a novel approach to improve the power factor (PF) and reduce the harmonics generated by an adjustable-speed drive (ASD). A high-frequency (HF) current injection technique is used to improve the PF and harmonic performance. The HF current at the same switching frequency (33 kHz) is injected into the input of a front-end rectifier from the output of an HF inverter. The main feature of the circuit is that it does not require any additional active devices for current injection. The inverter driving the induction motor is operated using a sinusoidal pulsewidth-modulation technique. The circuit simulation and experimental prototype results are presented for 67-hp (50 kW) and 3-hp three-phase induction motors, respectively.

Simplified Space Vector Modulation Techniques for Multilevel Inverters

This paper presents simplified techniques for the space vector modulation (SVM) of any n-level multilevel inverter. Three techniques have been presented to simplify the identification of the nearest three vectors to the reference vector. The first two techniques are based on resolving the multilevel inverter space vector diagram into appropriate two-level hexagons. This results in simplification of the multilevel SVM problem into a two-level SVM problem. The third technique is an algorithm-based technique which makes use of a 60°-spaced gh coordinate system to perform the SVM of a multilevel inverter. Switching sequence design for all the three techniques is presented with the aim of minimization of the device switching frequency. Simulation and experimental results have been provided to verify the feasibility of the proposed techniques. Simulation results are provided for up to 21-level cascaded H-bridge (CHB) inverters, while the experimental verification is done on a five-level laboratory prototype. Although only the CHB inverter is considered in this study, the proposed techniques are perfectly general and can be applied to all types of multilevel inverters, and are extendable to any number of levels.

Torque Ripple Minimization in Direct Torque Control Induction Motor Drive Using Space Vector Controlled Diode-clamped Multi-level Inverter

Abstract The combination of space-vector modulation and direct torque control is presented in this article to reduce the torque ripple contents in a medium-power adjustable speed drive system of induction motor. The drive is supplied by a five level diode-clamped inverter. The results show improvement in the torque ripple contents compared with a conventional direct torque control scheme. The experimental results of output voltage of the system for a diode-clamped multi-level inverter are also presented.

Stator Winding Inter-turn Insulation Fault Detection in Induction Motors by Symmetrical Components Method

Abstract The theory of instantaneous symmetrical components is used for the detection of insulation faults in a three-phase induction motor. Based on the experimental data of motor intake currents and the system voltages, the loci of positive- and negative-sequence components of currents are plotted. These loci overlap with each other under healthy winding conditions as their major and minor axes coincides. When an inter-turn short circuit occurs, these axes do not coincide with each other and displacement angle ϕ appears between two major axes. Thereby, the non-overlapping area comes into existence. The proposed system considers the effects due to unbalance in voltages, asymmetry in stator winding design, and measurement errors. Experimental results are reported to demonstrate the effectiveness of the proposed technique at different load conditions.