Battery energy storage system based controller for a wind turbine driven isolated asynchronous generator

This paper presents an investigation of a voltage and frequency controller for an isolated asynchronous generator (IAG) driven by a wind turbine and supplying 3-phase 4-wire loads to the isolated areas where a grid is not accessible. The control strategy is based on the indirect current control of the VSC (voltage source converter) using the frequency PI controller. The proposed controller consists of three single-phase IGBT (Insulated Gate Bipolar Junction Transistor) based VSC, which are connected to each phase of the IAG through three single phase transformers and a battery at their DC link. The controller has the capability of controlling reactive and active powers to regulate the magnitude and frequency of the generated voltage, harmonic elimination, load balancing and neutral current compensation. The proposed isolated system is modeled and simulated in MATLAB using Simulink and PSB (Power System Block-set) toolboxes to verify the performance of the controller

H-bridge VSC with a T-connected transformer for a 3-phase 4-wire voltage and frequency controller of an isolated asynchronous generator

This paper deals with a novel solid state controller (NSSC) for isolated asynchronous generator (IAG) feeding 3-phase 4-wire loads driven by constant power prime movers, such as uncontrolled pico hydro turbines. AC capacitor banks are used to meet the reactive power requirement of the asynchronous generator. The proposed NSSC is realized using a set of IGBTs (Insulated gate bipolar junction transistors) based current controlled 2-leg voltage source converter (CC-VSC) and a DC chopper at its DC bus, which keeps the generated voltage and frequency constant in spite of changes in consumer loads. The neutral point of the load is created using a T-configuration of the transformers. The IAG system is modeled in MATLAB along with Simulink and PSB (power system block set) toolboxes. The simulated results are presented to demonstrate the capability of isolated generating system consisting of NSSC and IAG driven by uncontrolled pico hydro turbine and feeding 3-phase 4-wire loads

A novel solid state controller for parallel operated isolated asynchronous generators in pico hydro systems

This paper deals with a novel solid state controller (NSSC) for parallel operated isolated asynchronous generators (IAG) feeding 3-phase 4-wire loads in constant power applications, such as uncontrolled pico hydro turbines. AC capacitor banks are used to meet the reactive power requirement of asynchronous generators. The proposed NSSC is realized using a set of IGBTs (Insulated gate bipolar junction transistors) based current controlled 4-leg voltage source converter (CC-VSC) and a DC chopper at its DC bus, which keeps the generated voltage and frequency constant in spite of changes in consumer loads. The complete system is modeled in MATLAB along with simulink and PSB (power system block set) toolboxes. The simulated results are presented to demonstrate the capability of isolated generating system consisting of NSSC and parallel operated asynchronous generators driven by uncontrolled pico hydro turbines and feeding 3-phase 4-wire loads

Three-phase 4-wire isolated wind energy conversion system employing VSC with a T-connected transformer for neutral current compensation

This paper presents a voltage and frequency controller (VFC) for a 4-wire stand-alone wind energy conversion system (WECS) employing an asynchronous generator. The proposed VF controller consists of a three leg IGBT (Insulated Gate Bipolar Junction Transistor) based voltage source converter and a battery at its DC bus. The neutral terminal for the consumer loads is created using a Tconnected transformer, which consists of only two single phase transformers. The control algorithm of the VF controller is developed for the bidirectional flow capability of the active power and reactive power control by which it controls the WECS voltage and frequency under different dynamic conditions, such as varying consumer loads and varying wind speeds. The WECS is modeled and simulated in MATLAB using Simulink and PSB toolboxes. Extensive results are presented to demonstrate the capability of the VF controller as a harmonic eliminator, a load balancer, a neutral current compensator as well as a voltage and frequency controller

A voltage and frequency controller for stand alone pico hydro generation

This paper deals with a voltage and frequency (VF) controller for an isolated power generation system based on an asynchronous generator (AG) driven by a pico hydro turbine. The proposed controller is a combination of a static compensator (STATCOM) and an electronic load controller (ELC) for decoupled control of the reactive and active powers of the AG system to control the voltage and frequency respectively. The proposed generating system along with its VF controller is modeled in MATLAB using SIMULINK and PSB (Power System Block Sets) toolboxes. The performance of the controller is verified for the proposed system and feeding various types of consumer load such as linear/non-linear, balanced/unbalanced and dynamic loads

Estimates of combining ability and standard heterosis for grain yield and various agromorphological traits in rice (Oryza sativa L.)

A study was conducted for estimating combining ability and standard heterosis for grain yield and various agromorphological traits involving 10 parents and their 45 F1s (half diallel) during 2012-13 and 2013-14. The results of present investigation revealed that additive gene action played a predominant role in the inheritance of most of the traits under study. On the basis of general combining ability (GCA) effects and specific combining ability (SCA) effects, three parents (Vallabh Basmati 21, Pusa Basmati 1, CSR 13) and three crosses (Vallabh Basmati 21 x Pusa 1121, Pusa 1121 x CSR 13 and Pusa Basmati 1 x CSR 13) were found good general and specific combiners. The best combinations mostly involved good x good and good x poor parental GCA effects suggesting that there is addi-tive x additive and additive x dominance type of gene action for yield and other component traits. The cross showing additive gene action can be improved by pedigree breeding and selection can be postponed to later generations. The most appropriate breeding method for the exploitation of non additive gene action will be heterosis breeding. The six best cross combinations (Vallabh Basmati 21 x CSR 30, CSR 30 x CSR 13, Vallabh Basmati 21 x CSR 13, CSR 30 x Pusa basmati 1, Pusa basmati 1 x CSR 13 and Vallabh Basmati 21 x Pusa basmati 1) had significant standard heterosis for grain yield and other component traits. The crosses which showed significant standard heter-osis is highly suitable for commercial exploitation of heterosis in rice crop

Estimates of genetic parameters for grain yield, various yield components and some quality traits in rice (Oryza sativa L.)

A study was conducted during two crop season (Kharif, 2011-12 and 2012-13) for estimating the genetic parameters by involving 10 parents and their 45 F1s in rice crop. The estimates of h2 (overall dominance effects) were positive and significant for days to 50 % flowering (9.11), days to maturity (0.24), plant height (2.95), panicle length1(39), productive tillers per plant (3.22), branches per panicle (5.61), flag leaf area (5.50), 1000-grain weight (0.27), biological yield (7.35) and amylose content (1.03) which indicated dominance of genetic components in F1s crosses. The theoretical value (0.25) of (H2/4H1) for all the traits except kernel length and amylose content indicated the asymmetrical distribution of positive and negative genes in the parents. The proportion of dominant and recessive alleles for panicle length, productive tillers, branches per panicle, 1000 grain weight, biological yield, kernel length and L/B ratio reflected more dominant alleles, whereas for days to 50 % flowering, days to maturity, plant height, grains per panicle, flag leaf area, grain yield, harvest index, kernel breadth, kernel length after cooking, elongation ratio, amylose content and hulling %, reflected more recessive alleles in the parents. The estimates of specific combining ability (SCA) effects revealed that the cross Vallabh Basmati 21 x Pusa 1121 could be an excellent candidate for improving grain yield (1.52**), harvest index (1.86**) and flag leaf area (6.20**) whereas Pusa 1121 x CSR 10 is excellent candidate for panicle length (0.89**) and amylose content (1.54**). The characters showing more than 60 % narrow sense heritability along with positive and significant correlation with each other and also with grain yield could be rewarding for further improvement of yield and quality in rice. Therefore, these parental lines can be used as donors in future by following bi-parental mating and the diallel selective mating system could be the best breeding method in an early segregating generation for improvement in these traits in rice crop