Tanmoy Maity

Wireless Communication and Environment Monitoring in Underground Coal Mines – Review

ABSTRACT Environment monitoring in underground coal mines has been a mandatory requirement to ensure safe working conditions in mines. There is a need to develop active communication and information network to quickly detect the underground condition and accurately provide location references to evacuate workers from the dangerous zone. This paper addresses the recent technological comprehensive developments in the area of communication and environment monitoring in underground coal mines. It points out the suitability of application of recently developed wireless sensor network for this purpose as proposed by different researchers all over the world. The possibility of image, video surveillance, and use of robot are also explored here. Need of real-time implementation of proper system inside regulated and hazardous mining environment is evaluated in details.

Study of the suitability of recently proposed quasi Z-source inverter for wind power conversion

The paper presents quasi z-source inverter (QZSI) as an alternate converter system for single phase wind generator. The QZSI inheriting all the advantages of traditional ZSI replaces the conventional PWM inverter in the system with some of its additional utilities. A closed loop controller is developed which monitors wind generator output and adjusts the inverter shoot-through duty cycle employing third harmonic injection constant boost control technique. The whole system is modeled, analysed and verified through simulation and hardware arrangement. The system can provide stable voltage through proper selection of boost factor. Dynamic and steady states of the proposed system are studied to find out the suitability of maintaining the terminal voltage at desired level for direct-driven wind power system.

Intelligent Online Measurement and Management of Energy Meter Data through Advanced Wireless Network

Recently the Electrical supply companies are trying to adopt the electronic measurement of energy consumption data because of reduced manufacturing cost, improved measurement accuracy, increased timely information, miniature size and many other benefits that go well beyond the traditional rotor-plate energy meter type. In this paper with the help of an energy chip, an improved energy metering solution is developed, where automating the progression of measurement through digital wireless communication technique is adopted to get the above benefits alongwith smooth control. The developed energy meter calculates the total average active power mainly for residential consumers. The hardware circuit accepts single phase voltage and currents as its inputs and provides the output in the form of logic data proportional to the average real power. This data is fed to a remote computer server through the wireless ZigBee network that represents the concept of distant wireless metering, practically involving no manpower. This paper also presents a software solution developed for total electrical energy billing and data management system.

Design of surveillance and safety system for underground coal mines based on low power WSN

This paper presents a low power, cost-effective, and ZigBee protocol based wireless sensor network that provides an intelligent surveillance and safety system for underground coal mines. The system consists of wireless connection of several nodes. Sensor node mainly consists of ZigBee protocol based low power CC2530 transceiver integrated with a high performance, low power microcontroller on single chip. This integrated chip connected through RF connector on smartRF05 Battery Board. This small size, low power device is easily interfaced with desired miniature size sensors. Wireless sensor nodes join to other sensor node in specific multi-hop mesh network topology, that creates a ZigBee based wireless sensor network. This network can be easily placed in underground mines and it provides an effectively surveillance and safety system for underground coal miners. Especially, it provides the real-time data communication between miners and surface control room through highly secure, reliable wireless sensor nodes. The proposed system improves the existing miners safety and early warning surveillance in underground coal mines.

Real-time simulation for performance evaluation of bidirectional quasi z-source inverter based medium voltage drives

Purpose – The purpose of this paper is to present the performance of medium voltage induction motor drive fed through a bidirectional quasi z-source inverter (BQ-ZSI). By controlling the shoot-through duty ratio, BQ-ZSI is able to produce desired stable AC output voltage even during the situation of critical power supply variation. BQ-ZSI based drive has unique properties like boosting the output voltage during voltage sag, reducing harmonic distortion and improving the input power factor. Generally, adjustable speed drives are interrupted due to voltage sag in input supply that causes manufacturing and commercial losses. Replacing the conventional converter with BQ-ZSI, it can eliminate those common operational constraints. Design/methodology/approach – This purpose is validated through simulations using real-time digital simulator (RTDS). RTDS is based on FPGA that interfaces the digital and analog inputs and outputs ports of the external hardware device. The IGBT based BQ-ZSI closed loop induction moto...

Z-source inverter based control of wind power

Impedance (Z)-source inverter can provide stable output by smooth controlling of shoot-through duty cycle of any of the traditional PWM bridge inverters. In this paper a control system for impedance-source inverter is designed suitable for wind power conversion system. The main challenge in wind power system to maintain a constant voltage at the output with unpredictable variation in wind speed, is suitably taken care in steady state through buck-boost-capability of z-source inverter (ZSI). The shoot through state of ZSI is able to control and boost the output voltage when the wind generator voltage is not more enough to directly generate the desired output. Again, the non-shoot through state can control and buck the output voltage when the wind generator voltage is more than desired. So, the z-source PWM inverter replacing the conventional PWM inverter provides the unique output voltage regulation feature by making an appropriate choice of buck-boost factor. The closed loop controller carefully monitors the wind generator voltage and controls the shoot-through and non-shoot through duty cycles automatically. The whole system is simulated under arbitrary input variation condition and results are presented. A comparison between the traditional and z-source inverter based system is also presented, which clearly indicates the benefits of the proposed system.

A novel three phase energy meter model with wireless data reading and online billing solution

Measurement of data electronically leads a combination of benefits that go well beyond the traditional rotor-plate energy meter design. In this paper with the help of an energy chip, an improved novel three phase energy metering solution is developed. Automating the progression of measurement through digital wireless communication technique is done to get high accuracy, smooth control and better reliability. The developed energy meter calculates the total average active power mainly for industrial and commercial applications. The hardware circuit accepts three phase voltages and currents as its inputs and provides the output in the form of serial interfaced data equivalent to the average real power. This serial data is fed to a remote personal computer through the wireless ZigBee network that represents the concept of distant wireless metering, practically involving no manpower. The paper also presents a software solution developed for total electrical energy billing and data management system.

Real-time performance analysis of modified z-source inverter-fed induction motor drives using xilinx system generator

Abstract This paper contributes to the performance evaluation of modified z-source inverter (ZSI) for medium voltage induction motor drives using the Xilinx System Generator. Controlling the shoot-through duty ratio of the modified ZSI, can boost the inverter output voltage during input voltage sags and maintain the desired output voltage level at the motor terminal. The proposed drive system eliminates voltage sag problem and surpasses the demerits of the traditional voltage source inverter drives. The proposed system is executed in FPGA based real-time digital simulator at fixed step solver with fixed-time step and constant switching frequency. Real-time simulation results show the performance of 225 KW, 3.3 kV induction motor for modified ZSI based adjustable speed drives during steady and dynamic states.

Recent developments in mine hoists drives

This paper presents a comprehensive literature review for mine hoist drives. Both DC and AC drives with their control techniques are discussed with a comparative study on their performance. Many recent control techniques using power electronic based systems are also discussed. The future trend in this area is also addressed. This review paper is the first of its kind information source provider for mine winder drives to be useful for researchers, designers and application engineers in the mining industry.

Energy saving techniques for ventilation fans used in underground coal mines—A survey

As the energy consumption to operate a ventilation system is 25 to 50% of the total energy requirements of an underground coal mine, proper planning, redesign, implementation and maintenance are necessary to achieve energy saving in this potentially viable area. Many researchers all over the world are therefore busy with solution for optimizing the consumption of energy in ventilation system. In this paper, the energy saving possibilities is discussed from different angles and a survey of current research is presented particularly on potential for electrical energy cost saving by implementation of various new technologies/methods. Ventilation demand in coal mines may vary throughout the year and by designing/developing a good ventilation system can not only minimize the cost of energy for the fan but also try to create healthy environment in mine. A number of recent commercially available systems are also reviewed in the paper to get the proper understanding.