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A two-level voltage source inverter (2L-VSI) when working under overmodulation regulation potentially has low performance, especially during large reference or load changes. To address this problem, a new calculation method is proposed in this article by determining a new reference vector from the boundary of linear-modulation zone as a best vector. The reference vector is synthesized by one or two vectors on the boundary line. Therefore, this technique simplifies the calculations to obtain the duty cycles and uses these duty cycles to identify the overmodulation zones. The proposed method is applied to the modulated model predictive control (MMPC) and the space vector modulation, respectively, in a 2L-VSI. A comprehensive assessment mathematically proves that both methods are in consistence with each other. Simulations and experiments are carried out to show that the proposed methods can reduce the computational burden and implementation complexity and improve the performance of the 2L-VSI in terms of fast dynamic response and smooth transition between the linear-modulation zone and overmodulation zone.

The Permanent Magnet-Assissted Synchronous Reluctance Motor (PMA-SynRM) drive has become one of the most interesting replacements for the high efficiency variable speed drive. Herein, sensorless predictive torque control of a PMA-SynRM with non-sinusoidal back electromotive force (Back-EMF) is introduced. In order to control PMA-SynRM, finite control set-model predictive control (FCS-MPC) is implemented by means of a two-level inverter. Furthermore, an improved form of FCS-MPC, i.e., direct mean torque control (DMTC), is utilized as a second method to control PMA-SynRM. For improving the sensorless the combination of Extended Kalman Filter (EKF), Adaptive Filter (AF) and quadrature Phase-Locked Loop (PLL) are used for better estimation of the non-sinusoidal back EMF, elimination of the high order harmonics, and the accurate estimation of position and speed rotor, respectively. The simulation result in effectively minimizing torque ripples compared to conventional FCS-MPC. The outcomes of the observer simulation are successfully guaranteed the accurate estimation of speed and rotor position.

In this paper, considering two different scenarios, combined cycle power plant was optimized to reduce total system costs. In the first scenario, parameters of combined cycle power plant were optimized based on power system constraints. But, in the second scenario, they were optimized considering constraints of the power plant. Cost function of power plants includes consumable fuel price (natural gas), maintenance and repair cost and exergy destruction cost, which was fitted with a quadratic equation in this investigation. In both scenarios, combined cycle power plants were optimized by genetic algorithm based on two objective functions of total exergy efficiency of power plant and price function of generated power. The results obtained from these two scenarios showed that the second scenario introduced more optimized cost function than the first one. As a result, calculating cost function of power plant apart from the power system reduced costs of combined cycle power plant and total system and applying constraints of the power system to power plants discharged them from their optimized function and increased the costs.