Comparative Analysis of DITC Based Switched Reluctance Motor Using Asymmetric Converter and Four-Level Converter

High torque ripple is the main draw of Switched Reluctance Motor (SRM) compared to other conventional motor. Torque ripples can be minimized by Direct Instantaneous Torque Control (DITC) technique. DITC responds against the torque error instantaneously by using hysteresis torque controller and regulate the torque output of the motor within hysteresis band.This paper compares the performance of Switched Reluctance Motor in terms of torque ripples with DITC strategy for both Asymmetric converter and Four-level converter. Asymmetric converter has three states namely magnetization, freewheeling and demagnetiztion states. With four-level converter, fast magnetization and fast demagnetization are also possible. Thus, the current build up and decay time is reduced which improves the dynamic performance. SRM is simulated using DITC scheme with Asymmetric converter and Four-level converter in MATLAB/SIMULINK to analyze torque ripples and it is observed that DITC with four level converter is better than that with Assymetrical converter

Comparative Analysis of DITC Based Switched Reluctance Motor Using Asymmetric Converter and Four-Level Converter

High torque ripple is the main draw of Switched Reluctance Motor (SRM) compared to other conventional motor. Torque ripples can be minimized by Direct Instantaneous Torque Control (DITC) technique. DITC responds against the torque error instantaneously by using hysteresis torque controller and regulate the torque output of the motor within hysteresis band.This paper compares the performance of Switched Reluctance Motor in terms of torque ripples with DITC strategy for both Asymmetric converter and Four-level converter. Asymmetric converter has three states namely magnetization, freewheeling and demagnetiztion states. With four-level converter, fast magnetization and fast demagnetization are also possible. Thus, the current build up and decay time is reduced which improves the dynamic performance. SRM is simulated using DITC scheme with Asymmetric converter and Four-level converter in MATLAB/SIMULINK to analyze torque ripples and it is observed that DITC with four level converter is better than that with Assymetrical converter

Data-efficient Neuroevolution with Kernel-Based Surrogate Models

Surrogate-assistance approaches have long been used in computationally expensive domains to improve the data-efficiency of optimization algorithms. Neuroevolution, however, has so far resisted the application of these techniques because it requires the surrogate model to make fitness predictions based on variable topologies, instead of a vector of parameters. Our main insight is that we can sidestep this problem by using kernel-based surrogate models, which require only the definition of a distance measure between individuals. Our second insight is that the well-established Neuroevolution of Augmenting Topologies (NEAT) algorithm provides a computationally efficient distance measure between dissimilar networks in the form of "compatibility distance", initially designed to maintain topological diversity. Combining these two ideas, we introduce a surrogate-assisted neuroevolution algorithm that combines NEAT and a surrogate model built using a compatibility distance kernel. We demonstrate the data-efficiency of this new algorithm on the low dimensional cart-pole swing-up problem, as well as the higher dimensional half-cheetah running task. In both tasks the surrogate-assisted variant achieves the same or better results with several times fewer function evaluations as the original NEAT.Comment: In GECCO 201

Implementation of FPGA in the Design of Embedded Systems

The use of FPGAs (Field Programmable Gate Arrays) and configurable processors is an interesting new phenomenon in embedded development. FPGAs offer all of the features needed to implement most complex designs. Clock management is facilitated by on-chip PLL (phase-locked loop) or DLL (delay-locked loop) circuitry. Dedicated memory blocks can be configured as basic single-port RAMs, ROMs, FIFOs, or CAMs. Data processing, as embodied in the devices’ logic fabric, varies widely. The ability to link the FPGA with backplanes, high-speed buses, and memories is afforded by support for various single ended and differential I/O standards. Also found on today’s FPGAs are system-building resources such as high speed serial I/Os, arithmetic modules, embedded processors, and large amounts of memory. Here in our project we have tried to implement such powerful FPGAs in the design of possible embedded systems that can be designed, burned and deployed at the site of operation for handling of many kinds of applications. In our project we have basically dealt with two of such applications –one the prioritized traffic light controller and other a speech encrypting and decrypting system

Continuous Depth Recurrent Neural Differential Equations

Recurrent neural networks (RNNs) have brought a lot of advancements in sequence labeling tasks and sequence data. However, their effectiveness is limited when the observations in the sequence are irregularly sampled, where the observations arrive at irregular time intervals. To address this, continuous time variants of the RNNs were introduced based on neural ordinary differential equations (NODE). They learn a better representation of the data using the continuous transformation of hidden states over time, taking into account the time interval between the observations. However, they are still limited in their capability as they use the discrete transformations and a fixed discrete number of layers (depth) over an input in the sequence to produce the output observation. We intend to address this limitation by proposing RNNs based on differential equations which model continuous transformations over both depth and time to predict an output for a given input in the sequence. Specifically, we propose continuous depth recurrent neural differential equations (CDR-NDE) which generalizes RNN models by continuously evolving the hidden states in both the temporal and depth dimensions. CDR-NDE considers two separate differential equations over each of these dimensions and models the evolution in the temporal and depth directions alternatively. We also propose the CDR-NDE-heat model based on partial differential equations which treats the computation of hidden states as solving a heat equation over time. We demonstrate the effectiveness of the proposed models by comparing against the state-of-the-art RNN models on real world sequence labeling problems and data

Enhancing Growth and Yield in Banana Cv. Robusta (AAA) through Fertigation with Microbial Consortium

Studies were carried out at Indian Institute of Horticultural Research, Bangalore, to test the effect of fertigation with a consortium of biofertilizers for sustainable production in banana cv. Robusta (AAA). The combination of fertigation and consortium of biofertilizers significantly influenced yield and yield-attributing characters in both primary and ratoon crops. Fertigation with 100% recommended dose of fertilizers along with the consortium of biofertilizers recorded significantly higher yield compared to soil application of fertilizer, farm yard manure and consortium of biofertilizers. However, yield difference between 100% and 75% recommended dose of fertilizers was not significant. Likewise, yield difference between 75% and 50% recommended dose of fertilizers (RDF) too did not differ significantly, although yields declined at 50% RDF. Other growth characters such as number of leaves and plant girth were also significantly influenced by the combined application of fertigation and the consortium of biofertilizers in both main and the crops. However, plant height, number of hands per bunch and TSS were not affected by these treatments. Pulp-to-peel ratio significantly differed in both the main plant and ratoon crops, but days to maturity differed significantly in the ratoon crop. Main plant crop yields were higher compared to that in ratoon. N and K accumulation was significantly higher at 100% fertigation with 300g of the consortium of biofertilizers in both the seasons. However, accumulation of phosphorous was higher at 100% fertigation with 300g of the consortium of biofertilizers (CBF) in the plant crop whereas, in the ratoon crop, highest accumulation of P in the stem was observed at 100% RDF+100g CBF, and, in the leaf and fruit, at 100% RDF with 300g and 200g of CBF, respectively

Evaluation and Improvement of Distribution System Reliability Indices using ETAP Software

Reliability assessment is the most important factor in designing and planning of distribution system that should operate in an economical manner with minimal interruption of customer loads. This is due to the fact that the distribution system provides the final link between a utility transmission system and its customers. It is observed that more than 80% of all customer interruptions occur (i.e., power quality issues) due to component failures in the distribution system. That report quantifies the expected reliability indices such as interruption frequency and interruption duration during the entire year. Many research findings are out there to assess the reliability of the power system. Further, due to the wide growth of distributed generation in electrical power, investigating their impact on system reliability, it becomes an attractive area of research. In this paper, the reliability evaluation of distribution system using a minimal cut set method based on the FMEA technique is described and applied to the IEEE RBTS Bus-2 and Indian practical distribution system (33/11 kV). Development of ETAP software is presented for calculating reliability indices. Further, improvement of reliability with introducing of Distributed Generation is presented. Reliability indices are load point indices and system indices which includes, System Average Interruption Frequency Indices (SAIFI), System Average Interruption Duration Indices (SAIDI), Customer Average Interruption Frequency Indices (CAIFI), Customer Average Interruption Duration Indices (CAIDI), Energy Not Supplied (ENS), Average Energy Not Supplied (AENS), etc. These indices are shows the reliability performance of the system

Simulation of a high voltage gain dc-dc converter integrating with coupled inductor and two voltage multiplier cells

In this paper, a high voltage gain dc-dc converter is presented for renewable energy applications. This paper develops step up converter which consists of two voltage multiplier cells with coupled inductor in order to achieve the multiple voltage requirements with high voltage gain. And also two capacitances are provided for charging when the device is under turned-off condition, by utilizing the stored energy levels in the coupled inductor which can enhances the voltage transfer capability levels of the system The voltage imbalance levels are compensated at main power switch. The implemented model operates with low resistance RDS(ON) at main power switch which can reduce the switching losses. The developed simulink models are tested and verified within the MATLAB/SIMULINK with multiple output functions with high voltage gains