Current Issue : July - September Volume : 2014 Issue Number : 3 Articles : 5 Articles
Thecomplicatedmodulation algorithm and the high switching frequency are twomain hindrances in the analysis and simulation of\nmatrix converters (MCs) based systems. To simplify the analysis and accelerate the simulation ofMCs, a unique dynamic model is\npresented for theMC, which is independent ofMC type (direct or indirect) and the modulation algorithm. All the input and output\nvariables are transferred to the respective reference frames and their relations and limits are calculated. Based on the proposed\nequations, an equivalent circuit model is presented which can predict all the direct and indirect matrix converters dynamic and\nsteady state behaviors without the need for small simulation time steps.Validity of the proposed model is evaluated using simulation\nof the precise model. Moreover, experimental results from a laboratory matrix converter setup are provided to verify the accuracy\nof the simulation results....
This paper designs a hybrid speed controller in which a Sine Triangle PulseWidth Modulated (SPWM) inverter is used below the\nbase speed and a square wave inverter is employed above the base speed. The two inversion techniques complement each other\nfor their advantages and disadvantages below and above the base speed. This paper proposes a unique strategy for the transition\nbetween SPWMand square wave by simply setting the frequency of the carrier signal equal to zero.Theproposed methodology in a\nway uses only one inversion technique and realizes a seamless transition fromthe SPWMto square wave compared to conventional\nmethod in which modes are simply switched from SPWM to square wave and vice versa when the speed changes above and below\nthe base speed, respectively. Computer simulations show that the proposed technique has smoother torque transition and thus a\nbetter speed response compared to conventional approach of inverter mode switching around the base speed.The performance of\nproposed hybrid approach is also validated on a small prototype induction motor through experimental results....
The novel solitary electromagnetic wave (SEMW) theory and the novel design methodologies of the switching mode power supply\ncircuit (SMPC) are presented.The SEMW theory was developed as a basic theory of the design of all kinds of the switching mode\ncircuit including SMPCby fusing the physics of semiconductor, nonlinear undulation, and electromagnetic wave.When the SEMW\ntheory is used, the electromagnetic analysis of SMPC becomes possible by using only the real parameters based on the physics. The\ntechnologies of the low impedance lossy line (LILL) which is used to the DC line and the matched impedance lossy line (MILL)\nwhich is used to the switching line are also presented.They are effective for suppressing the electromagnetic interference. SMPC\ncan be reconfigured to the quasistationary state closed circuit (QSCC) by applying LILL and MILL in accordance with the SEMW\ntheory. No electromagnetic interference exist in QSCC. The buck converter which is one of the most popular DC-DC converters\nis presented as an example of the method for being reconfigured to QSCC. The conventional design tools which includes SPICE\nbased on the AC circuit theory will be effective for the design and analysis of the inside circuit of QSCC....
How can students be given experience in the confused realities of engineering processes? How can undergraduate students be\nconvinced that processes can be analyzed and improved? Computer simulations properly designed and applied could answer\nthese challenges revolutionizing education in Power Electronics. In recent years, computer simulation has been commonly used\nin education to motivate students in their learning and help teachers to improve their teaching level.The present paper focuses on\ndeveloping a speed controller for DC motors starting from theoretical aspects, passing through simulations, and finally reaching a\ncontrol prototype. The control theory is based on a nonlinear technique known as SlidingMode Control (SMC) involving artificial\nintelligence for optimization such as Fuzzy Logic (FL), Adaptive Neurofuzzy Inference Systems (ANFIS), and Genetic Algorithms\n(GAs)....
This paper presents a synchronous current control method for a three-level neutral point clamped inverter. Synchronous reference\nframe control based on two decoupled proportional-integral (PI) controllers is used to control the current in direct and quadrature\naxes. A phase disposition pulse width modulation (PDPWM) method in regular symmetrical sampling is used for generating the\ninverter switching signals. To eliminate the harmonic content with no phase errors, two first-order low pass filters (LPFs) are used\nfor the dq currents. The simulation of closed-loop control is done inMatlab/Simulink. The Vertex-5 field programmable gate array\n(FPGA) in Labview/CompactRio is used for the implementation of the control algorithm. The control and switch pulse generation\nare done in independent parallel loops. The synchronization of both loops is achieved by controlling the length of waiting time for\neach loop.The simulation results are validated with experiments. The results show that the control action is reliable and efficient\nfor the load current control...
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