Continuous Time Least Square PI Control Method for Quasi-Z Source Inverter

This paper presents the proposed model of proportional Integral (PI) controller using continuous time least square method (CT-LSM) for a quasi-Z source inverter (qZSI). PI control is one of the most applicable control methods in power systems. Then, CT-LSM is mainly a statistical optimization method including parameter estimation for nonlinear systems to control. The proposed model is designed to set a control structure without using the nonlinear loads of qZSI and also improve PI control applications against the nonlinear system dynamics. Controller design for qZSI is divided into two parts which are explained as dc side and ac side in both two mode operations. For the dc side of the system, PI controller is designed according to approved system and its estimated parameters which are calculated from state space analysis of qZSI. As for the ac side, the voltage and current regulations are controlled in order to transfer the power to inverter legs based on design criteria. Simulation results by using the current qZSI model on Matlab/Simulink are used to research and analyze the effectiveness and efficiency of the proposed control design

Effects of second housing and recreational use on Pancratium maritimum L. population in western Black Sea region of Turkey

WOS: 000279103700052An experiment was conducted to investigate the effects of second housing development and heavy use recreational activities on sea daffodil (SD; Pancratium maritimum L.) distribution on western Black Sea coast line of Turkey. In 2005, to protect the SD populations 1 m height chicken wire-cages were placed on 20 m x 30 m areas in different parts of the shore. To compare the protected area (PA) with unprotected area (UA) 16 sampling areas were chosen along the coast line. Adjacent to each sampling plot a control plot from unprotected area was established. Additional data were collected from sampling plots established in four areas with different intensities of settlement. Data were utilized to relate the SD ground coverage, number of individuals and spikes per individual to the disturbance intensity. Three 1 m x 1 m quadrats were randomly placed on each plot. On each quadrat the ground coverage of SD and whole vegetation were determined with Braun-Blanquet. Then, the number of SD individuals and spikes of individuals were counted. Data indicated that there was no statistical difference between the PA and UA in vegetational ground coverage. However, the ratio of SD on these coverages was doubled in PA compared to the UA (P = 0.001). Analysis of the data collected from different locations in disturbed areas showed that intensity of disturbance has significant (P = 0.001) correlation with SD ground coverage (r(2)=0.45). The number of SD individuals (P = 0.001) and spikes per individual (P = 0.001) were significantly different between the PA and UA. SD individuals in UA were about 64% less than that of PA. Spike number per SD individual was also 66% lower in UA compared to PA. SD ground coverage was significantly (P = 0.001) related to number of individuals (r(2)=0.83). Settlement density made a significant effect on number of SD, number of spikes, SD ground coverage and whole plant ground coverage (P = 0.001). Analysis of data indicated that area usage type also made statistically significant differences on number of SD, number of spikes, SD ground coverage and whole plant ground coverage (P = 0.001). Results of the study indicate that SD populations are under threat because of intensive housing development and recreational usage in the coastal areas of Western Black Sea region of Turkey. Protection efforts revealed positive results in terms of SD survival and reproduction capacity in the coastal sand dunes