Majlesi Journal of Energy Management
Volume:10 Issue: 3, Sep 2021

In this paper, design and simulation of an electroosmotic micropump for use in biomedical applications and drug delivery devices is reported. This electroosmotic micropump is based on MEMS technology and is fully compatible with the processes of manufacturing of electromechanical systems. The basis of the proposed micropump structure is based on the electroosmotic phenomenon and the main idea used in the proposed structure is to use the technique of increasing fluid and wall contact within the main channel of the micropump. To this end, the use of internal microchannels along the main channel path has been used; these embedded microchannels, by increasing the contact surface between the fluid and the wall, enhance the electroosmotic effect inside the micropump, resulting in an increase in fluid velocity and the output flow rate. Simulation results show that the minimum speed of a simple micropump with a length of 600μm and a width of 300μm and applied potential of 10 volts without internal microchannels is equal to 0.22 mm/min. In the proposed structure, with the addition of 8 internal microchannels with a length of 90 μm and a width of 20 μm inside the main channel of the micropump, the flow rate of the fluid reaches 7.8 mm per minute. According to the simulation results it can be seen that, by adding the proposed microchannels to the electroosmotic micropump structure, the fluid outlet speed compared to the non-microchannel mode increases dramatically by up to 35 times at the same potential.

High efficient solar Photo-Voltaic (PV) inverters are demanded in recent electrical power scenario to satisfy the energy demand. The transformerless single stage T-Source Inverter (TSI) proposes high efficiency due to the voltage boost capability than the conventional Voltage Source Inverter (VSI) and Current Source Inverter (CSI). However in conventional VSI fed solar PV system, to increase the voltage from inverter additional transformer is used. The additional transformer used increases the total size, cost and power losses in the conversion process; as a result the efficiency of the system is reduced. This paper describes the analysis of solar PV system by employing T-Source Inverter (TSI) with Third Harmonic Injected Maximum Constant Boost (THIMCB) PWM control. This TSI based solar PV system overcomes the conceptual and theoretical limitations of VSI and CSI. The TSI have shoot through time period which is responsible for boost in voltage. The voltage stress of switching devices and harmonics are less when compared with the VSI fed solar system. The output voltage of the solar PV system can be increased by increasing the boost factor directly without using the step-up transformer or dc-dc booster circuit. The mathematical expressions for boost factor, shoot through duty ratio, voltage gain and voltage stress are obtained and validated by Matlab/Simulink simulation results.

In this study, wavelet transform is applied for three phase to ground fault detection and classification which occur at different locations in a 765 kV, 50 Hz twelve phase transmission line. The information of distorted energy, approximate and high frequency detail coefficients included in a fault current signal is captured using wavelet transform. Faulted phase determination is also carried out using the proposed technique concurrently. The effectiveness of the proposed protection technique is validated for three phase to ground faults, and various values of fault type, fault inception time, fault resistance, and fault location. Test results show that the proposed technique effectively detects the three phase to ground fault and discriminates the faulty phase effectively.

In this paper, a control strategy of a Double Fed Induction Machine (DFIM) is proposed; this method is the most responsive drive in terms of speed variations. In this configuration two voltage inverters connected to the stator and to rotor windings are used which have enabled spreading out the power between the stator and the rotor thanks to their distribution and pulsation in motor operation mode. In this research, a Field Oriented Control (FOC) strategy is used in the DFIM to regulate the speed without a mechanical sensor. Subsequently, an Extended Kalman Filter (EKF) is designed to estimate the DFIM speed real-time and to replace with the sensor. Finally, the proposed sensorless control strategy is validated by using simulation tests and compared to the FOC based on a speed sensor. The results have shown the sensorless FOC strategy could improve the control robustness and system’s performance in case of a fault.

Power transformers play an important role in the transmission and distribution of electrical energy. Power transformers increase or decrease the voltage level without changing the power and frequency of alternating current (AC) electricity. Power transformers are divided into oil type and dry type transformers. Both two types have disadvantages of high cost and isolation problems etc. These problems are reduced by the optimization of transformer design parameters. In this study, the most optimal design dimension is determined by using the firefly algorithm, which is a new heuristic approach in calculating the volume of oil type power transformers at least time. At the same time, the performance comparison is made with the most preferred genetic algorithm, which is one of the other intuitive methods, and the advantages of the firefly algorithm are revealed. This work will provide both cost and time benefits for transformer manufacturers.

Induction heating depends on several independent parameters such as the supplied energy, the heating time, the geometry of the piece to be heated, and the frequency of power supply. This latter strictly affects the variation of the power which depends directly on both the square of the current induced in the load and on the frequency. For this purpose, the supply of induction heaters needs to use high frequency converters as a suitable solution. The control of the inductor’s current requires development of advanced control techniques to ensure an acceptable precise regulation, with high efficiency and speed. In this research, a mathematical model of induction heating is represented with using the assembly (inductor-load), followed by the scheme of the chosen HT inverter, where, resonance is applied by a compensation capacitor in series with the load. Subsequently, the adapted predictive control laws are synthesized in order to control the current of the inductor, consequently, the power supplied to induction heating. The results of the simulation have shown the effectiveness of the control strategy.