DIGITAL CONTROL OF A CLOSED LOOP BUCK CONVERTER

The primary focus for the R&D in this area so far has been to figure out the best approach for evaluating and designing the DC-DC converter and perhaps the most appropriate control technique is being applied in different DC-DC converter circuits. Depending on power handling capacity as well as high-frequency switching, certain switching devices are chosen. This paper discusses the deployment of the digital PID controllers in the DC-DC converters. In an attempt to get a quicker response, voltage mode control has been used. Digital controllers started replacing traditional analog controllers more and more. Better immunity to changes in the environment which includes temperature and degradation of components, improved versatility by modifying the software, increasing advanced control methods, and decreased number of the components are the key benefits of the digital control against the analog control. A structured and concise strategy for designing a digitally operated close-loop Dc / Dc buck converter is discussed in this paper beginning with the Buck converter and giving the set of certain performance specification, implementations of the digital Proportional-IntegralDerivative(PID) controller is made. It addresses in depth all the appropriate DSP hardware and/or software methods and approaches needed to implement a controller. In order to illustrate the efficacy of the model, the dynamic response as well as the steady-state performance of controller is provided. The experimental outcomes fit well with the model of simulation. During the implementations of Switch Mode Power Supply (SMPS), application of dsPIC provides new perspectives towards affordable and versatile approaches of digital control.

An investigation to the design of high-precision wind sensing device based on piezoelectric array

A new wind sensing device based on bimorphs array is designed for apperceiving wind direction and velocity, whose structure is an L-shaped cantilevers array. A coupling model of the array is proposed to predict the response voltage stimulated by wind. By extracting the response voltage ([Formula: see text]) on each bimorph cantilever, the values of wind direction ([Formula: see text]) and velocity ([Formula: see text]) can be calculated in terms of the geometric relation. Further, the relations among wind errors, array amounts ( m) and array radius ( r) are acquired, and m & r can be utilized to decreasing angle error [Formula: see text] and velocity error [Formula: see text] of wind. The calculated and experimental results show that, increasing m initially yields decreasing these two errors, then it begins to increase the errors when m is larger than 6. The minimal wind angle and velocity errors of the array are 0.14° and 0.34%, respectively, at actual wind of 13.4 m/s, m = 6 and r = 20 mm. Meanwhile, increasing r can decrease [Formula: see text] and [Formula: see text], Besides, for calculating 20 random incidence wind angles, respectively, the range of wind velocity error is from 0.34% to 0.87%, the range of wind angle error is from 0.12°to 0.38°, and the response time is 10 ms.

A New Calibration Circuit Design to Reduce Drift Effect of RuO2 Urea Biosensors

The goal of this study was to reduce the drift effect of RuO2 urea biosensors. A new calibration circuit (NCC) based on the voltage regulation technique with the advantage of having a simple structure was presented. To keep its simplicity, the proposed NCC was composed of a non-inverting amplifier and a voltage calibrating circuit. A ruthenium oxide (RuO2) urea biosensor was fabricated to test the calibrating characteristics of the drift rate of the proposed NCC. The experiment performed in this study was divided into two main stages. For the first stage, a sound RuO2 urea biosensor testing environment was set-up. The RuO2 urea sensing film was immersed in the urea solution for 12 h and the response voltage was measured using the voltage-time (V–T) measurement system and the proposed NCC. The results of the first stage showed that the RuO2 urea biosensor has an average sensitivity of 1.860 mV/(mg/dL) and has a linearity of 0.999 which means that the RuO2 urea biosensor had been well fabricated. The second stage of the experiment verified the proposed NCC’s functions, and the results indicated that the proposed NCC reduced the drift rate of RuO2 urea biosensor to 0.02 mV/hr (98.77% reduction).