Ashok Jhunjhunwala

This paper illustrates the Battery Life Cycle Tester with intelligent charging and discharging unit comprising of measurement, data logging, remote monitoring and communication sections for data acquisition and control. The life cycle tester switches between different charging and discharging modes making it compatible with all battery chemistries. The discharger comprises of an electronic load using MOSFETs operated in their linear region to dissipate power. The required charging/discharging profiles for various applications like electric vehicle motor load and urban drive cycle tests can be programmed via an RS485 link and the data collection is done through Ethernet with an onboard SD card for backup. The user can also set their own test profiles within given limits. The Battery Life Cycle tester is used to perform required charging and discharging profiles at the specified Depth of Discharge (DOD), temperature, State of charge (SOC), charge and discharge rates for the desired number of cycles and store the data for analysis.

This paper describes and discusses the setting up of a DSP Cloud Lab, a setup to execute programs remotely. The programs can be executed on a variety of DSP boards; they could be microprocessor assembly language programs or programs written in assembly language requiring powerful DSP boards or even DSP boards with an FPGA accelerator. The boards used are based on Blackfin Architecture. For a student / developer who writes codes and tests on it, it appears as if they have exclusive use of the boards. However, the boards are highly shared, enabling a large number of students / developers to use them simultaneously. This paper also discusses the design choices made at different stages and the extent to which it facilitates or restricts the use of the DSP boards for a developer. © 2013 IEEE.

In this paper, we discuss efficient implementation of machine learning algorithms on DSPs. Specifically, we implement OCR and speech recognition on DSP and show how they can be optimized using fixed point routines. We illustrate the optimal usage of DSP resources like MAC units, shifters and software pipelining through assembly code structuring which massively reduces the MIPS consumed by the processor. We also describe how floating point overheads can be reduced by equivalent fixed point routines for real time implementations. Though the Blackfin-533 DSP is chosen for this illustration, the ideas presented here apply to other fixed point DSPs as well.

As the current world moves towards e-learning, this paper discusses about a recently developed remote Digital Signal Processing lab at IIT Madras. This lab enables the students to use Blackfin 537 based DSP kits to perform their real-time experiments / projects over the Internet. The DSP boards are custom made, with uClinux ported onto them, to facilitate a multi-user environment. This paper delineates the motivation, hardware setup, software setup and remote user access for using the laboratry. Finally the performance, scope and scalability are discussed with emperical data. © 2012 IEEE.

While Indian agriculture contributes merely 13.9% of the country's Gross Domestic Product, nearly 52% of the population still depends on agriculture for its livelihood. Close to half of the farmers are small farmers (owning 1.0 ha or less) facing near-stagnant productivity. This is due to several factors, but farmers often indicate that access to the right information at the right time is one of the most sought after need. Addressing this need to aid in the development of a productive and sustainable agricultural sector has certainly emerged as one of the major humanitarian challenges in India. There have been numerous efforts in this direction with the setting up of agricultural advisory systems, to provide information to farmers, but not many have succeeded in the objective of providing easily accessible, sustainable, personalized advisories to farmers. Recognizing this, the Indo-UK Advanced Technology Centre of Excellence in Next Generation Networks, Systems and Services (IUATC), a major technology transfer initiative, supported by the Department of Science and Technology (DST) in India and UK Government under the Digital Economy Theme is attempting to address the challenges in Indian agriculture through Information and Communication Technology (ICT) networks. This paper presents a functioning Agricultural Advisory System that has been built with the aim of bridging information gaps between farmers and agriculture knowledge workers (such as agricultural scientists and extension workers) and is an extension of a technology effort that has been previously presented. While our earlier work only discussed the potential of using an innovative ICT approach to providing personalized agricultural advisories, this paper covers details of the technology implementation, presents a brief summary of the impact analysis carried out with the farmers registered into our system and discusses new features that could make the system more effective.

The limitations of the conventional MPPT technique are oscillations of the system at steady state leading to energy loss, slower response and the occurrence of drift. A simple zonal based MPPT controller is proposed in this paper which addresses the above limitations without additional requirement of sampling or sensors apart from the basic voltage and current sensors. The proposed system is simple, cost effective and easy to implement. Phase shift reference (Duty) for the DC-DC converter is varied dynamically by the proposed MPPT controller depending upon the operating point voltage to have a better dynamic response. The error in the perturbation direction, if any, is corrected by the controller while computing the change in duty reference ΔD). This ensures the drift free operation. The response speed of the proposed controller is improved compared to the conventional controller by having a variable step size. Solar PV fed full bridge series resonance DC-DC converter with resistive load is considered for evaluating the proposed control scheme. The performance of the proposed MPPT control technique is verified by simulations and hardware results.

This paper presents an innovative approach to tackle the crisis of electrification of off grid and near off grid homes by using the innovative Inverterless Solar DC system. Improved efficiency, lower cost and robust design makes it a very attractive solution. Inverterless system is not only cost effective to power off grid homes but as and when grid becomes available, it can be seamlessly integrated. For homes which are connected to the grid but face load shedding, this system provides uninterrupted power. This paper presents the technical design details of this system.

Three wheelers are considered to be common mans vehicle and is used for various load carrying and passenger carrying applications across the globe. A novel Intelligent Solar Electric Bio Hybrid developed by Pi Beam Labs Pvt. Ltd with the help of IIT Madras which can be completely charged off grid and has increased battery life due to intelligent torque sensor controlled drivetrain is discussed in this paper. The paper presents the basic architecture, test results and its economic impact in the small load, short distance category of material handling. The present three wheeler sector has four categories namely IC engine power, electric motor powered, human powered and electric trikes. Among this the greener solution is electric trikes. Most of the E-trikes contain a throttle to control the motor and a pedal to assist the motor. This configuration will drain the battery faster and also reduces battery life as the user tends to use the throttle more. The typical battery life of such a vehicle is 6-8 months. In this context, this paper explains the concept of charging the entire vehicle using solar power and intelligently controlling the motor power using torque sensor. This will not allow the user to draw more current as it is in the case of throttle. This solar panel on the top charges the vehicle while it is running or parked. Additionally the paper contains the study on the application of the vehicle and its economic impact in various sectors.

Lighting, fans and electronic devices form a significant and growing portion of power-load at homes and need power back-up support in case there are frequent power-cuts. A Diesel generator is generally used today in multi-storied buildings to provide this backup. The DC system, proposed in this paper, provides a far more energy-efficient alternative using renewable power-source for backup. It creates a pull for a home to move towards far more energy efficient DC loads. The solution provides a GREEN option to the existing solution. This paper provides a fresh perspective on the problem of eliminating conversion losses for uninterrupted operation of DC appliances. A cost benefit analysis shows that this DC system can reduce costs to the consumer by eliminating the complex electronics embedded in the inversion process. A rough measurement of the conversion losses for commercially available inverters and battery chargers illustrates that gains of 30% to 45% are easily obtainable

India is a power deficit country and one third of its homes are off grid or near off grid. This paper presents an efficient and affordable Solar DC solution for powering such homes. Though several solutions have emerged in the past for powering these homes, those have been expensive and energy inefficient. These solutions rely on several DC to AC and AC to DC conversions, to feed the widely used AC home loads, thus, wasting a large chunk of the expensive power. The proposed Solar DC solution for off-grid homes (OGH) is developed to use the generated PV power efficiently. With this solution, the panel and battery size is reduced by 2 to 2.5 times and the cost to power a house is reduced to nearly half the cost of the existing solutions. The paper also presents a techno-economic comparison between the proposed OGH solution with some existing solar systems.