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SUMMARYThe current paper presents a novel Schmitt trigger using two second-generation current conveyors and four resistors and its application as a relaxation oscillator. The performance of the proposed circuit is examined using Cadence and the model parameters of a 0.6 m CMOS process. The obtained results demonstrate excellent agreement with the theoretical values. The measured results based on commercially available current feedback operational amplifiers (AD 844 AN) are included and the non-idealities are also examined. The topology reports low sensitivities and has features suitable for VLSI implementation.

By using two resistors and a single capacitor with second-generation differential current conveyor as an active element, a new square wave generator is proposed and implemented. The frequency of operation of the introduced model is varied with respect to the variation of remaining passive components. Maximum reduction in noise effects caused by parasitics generated during integrated circuit fabrication is achieved with the scheme of grounded capacitor. The mathematical model of the selected circuit is verified in both simulation and experimental mode and found having matched in all three aspects. The elevated advantages and merits of the given topology are compared and tabulated contrary to the existing standard models. Using Cadence virtuoso with gpdk 180 nm libraries, the circuit is verified with a supply rail voltage of ±2.5 V. Later, prototype is also tested with commercially available current feedback operational amplifiers of AD844AN.

The automatic load frequency control for multi-area power systems has been a challenging task for power system engineers. The complexity of this task further increases with the incorporation of multiple sources of power generation. For multi-source power system, this paper presents a new heuristic-based hybrid optimization technique to achieve the objective of automatic load frequency control. In particular, the proposed optimization technique regulates the frequency deviation and the tie-line power in multi-source power system. The proposed optimization technique uses the main features of three different optimization techniques, namely, the Firefly Algorithm (FA), the Particle Swarm Optimization (PSO), and the Gravitational Search Algorithm (GSA). The proposed algorithm was used to tune the parameters of a Proportional Integral Derivative (PID) controller to achieve the automatic load frequency control of the multi-source power system. The integral time absolute error was used as the objective function. Moreover, the controller was also tuned to ensure that the tie-line power and the frequency of the multi-source power system were within the acceptable limits. A two-area power system was designed using MATLAB-Simulink tool, consisting of three types of power sources, viz., thermal power plant, hydro power plant, and gas-turbine power plant. The overall efficacy of the proposed algorithm was tested for two different case studies. In the first case study, both the areas were subjected to a load increment of 0.01 p.u. In the second case, the two areas were subjected to different load increments of 0.03 p.u and 0.02 p.u, respectively. Furthermore, the settling time and the peak overshoot were considered to measure the effect on the frequency deviation and on the tie-line response. For the first case study, the settling times for the frequency deviation in area-1, the frequency deviation in area-2, and the tie-line power flow were 8.5 s, 5.5 s, and 3.0 s, respectively. In comparison, these values were 8.7 s, 6.1 s, and 5.5 s, using PSO; 8.7 s, 7.2 s, and 6.5 s, using FA; and 9.0 s, 8.0 s, and 11.0 s using GSA. Similarly, for case study II, these values were: 5.5 s, 5.6 s, and 5.1 s, using the proposed algorithm; 6.2 s, 6.3 s, and 5.3 s, using PSO; 7.0 s, 6.5 s, and 10.0 s, using FA; and 8.5 s, 7.5 s, and 12.0 s, using GSA. Thus, the proposed algorithm performed better than the other techniques.