Revista de sistemas eléctricos y electrónicos

This work demonstrates for the first time the implementation of a level-crossing analog-to-digital converter (LC-ADC) in a single, commercially available IC (that costs less than $2). The implementation utilizes adaptive threshold levels in order to prevent overload distortions for fast-changing signals. The entire design is based on a 20-pin PIC16F1769 microcontroller from Microchip and no external components are required. In fact, the only external circuitry required is a single jumper wire. This is due to the fact that the new generation of microcontrollers have integrated core-independent hardware, analog as well as digital. This design takes full advantage of the core-independent logic and analog blocks in a PIC16F17xx circuit to implement the LC-ADC technique that so far has required multiple-circuit designs or ASIC implementation. The design is demonstrated on a standard electrocardiogram (ECG) signal.

A pronounced concentration dependence of the time constant of fluorescence decay was found, disproving Strickler- Berg’s equation restricting molecular light emission to a local process. Thus, interactions were found significantly extending to more than 100 nm and make such systems promising for interfaces between molecular dots or more complex molecular arrangements and conventional macroscopic electronics.

AC to AC frequency converters had a challenge to be proposed as a reduction of THD. This challenge due to eliminate the most effective harmonics in frequency spectrum with low cost and no difficulty. However, the challenge is represented by producing new technique for AC to AC frequency changer with lower total harmonic distortion compared with regular AC to AC frequency changer. This proposed work introduces reduction based on eliminate the 3rd predominant harmonic by imposing a waveform with same frequency, amplitude and poly phase of presented harmful harmonic the elimination for the most effective harmonic will cause reduction in THD . The proposed technique gave a significant reduction in THD (about 52%) with respect to regular AC to AC frequency changer with low cost implementation requirements.

An analytical technique is proposed for allocation of shunt capacitor bank in radial distribution system. The objective is formulated to determine the size, number and location of capacitor bank for real and reactive power loss reduction, voltage profile enhancement and annual cost saving. A novel Loss-Voltage Sensitivity Factor (LVSF), has been incorporated in the technique. The value of LVSF decides the candidate bus location. The achievability of the proposed method (PM) has been demonstrated on IEEE-69 bus test system allowing comparing results with latest optimization techniques in literature. Further application of PM on 130 bus relatively large distribution system shows the effectiveness and robustness of the proposed technique. Capacitors allocated (size and location) during light loading condition simulation are forced as fixed capacitors in nominal and heavy loading simulations. This development is essential when allocated capacitors in nominal and heavy loading simulations do not include nodes of fixed capacitors.

This work presents a pilot-scale performance study intended at evaluate the achievability and operatability of biomass gasifier specially designed for hilly regions. The operations were carried out with forest wood blocks with around 35% moisture content. The gasifier was designed for 360 kWth downdraft modes operating with air at 15°C as gasifying agent. The designed gasifier system was installed in a green tea processing factory for supplying thermal energy for panning of green leaves. This system has replaced their conventional open wood firing rotary kiln furnace which was an in efficient combustion due to the ambient conditions. A performance study conducted on the gasifier system for their factory’s thermal demand had shown firewood saving of 35% over conventional panning operation. The economics of installation–cum–operation of the gasifier was also found to be acceptable enough the operation results are discussed.