Articles

  1. A UNIDIRECTIONAL MULTI-LEVEL SINGLE PHASE BRIDGELESS RECTIFIER TARGETING HIGH EFFICIENCYDownload Article

    1R.Kaviyapriya, 2Prof.R.Balasankar M.E., Ph.D.,

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    This paper with new multi-level unidirectional single-phase PFC rectifier topology is well-suited for applications targeting high efficiency and/or high power density. The characteristics of a selected novel rectifier topology, including its principles of operation, feedback control scheme, and a power circuit design related analysis are presented which include remarkably low switching losses and single ac side, boost inductor. To improve the characteristic and enable the use of higher switching frequencies, multilevel converters can be employed to build power factor correction rectifier topologies. With the multi-level topologies the losses are typically much lower since the voltage steps over the boost inductor ar e only one half of the dc-link voltage. Thus, the inductance and the size of the boost inductor are reduced. This achieve high power factor with reduced conduction and commutation losses which can be used for telecommunication applications. The reduction in conduction losses occurs because the proposed topology presents less power semiconductors in the current path. Thus the efficiency of the proposed topology tends to be higher since conduction losses will be lower. Keywords: Single phase, PFC, Topology, Frequencies, Voltage.

  2. SPEED AND FLUX CONTROL OF THE PM-BLDC MOTOR USING HYSTERESIS CONTROL TECHNIQUEDownload Article

    1C. Nandhini, 2Prof.A.Ambika M.E., (Ph.D.,)

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    Permanent Magnet Brushless DC (PM-BLDC) motors have become quite widespread and are utilized to serve for a variety of industrial purposes, because of their simple structure, high reliability and ease of control. Space Vectors theory is one of the most widely used methods which is implemented for controlling PM-BLDC. Supposing that each space vector refers to a unique arrangement of switch states, this theory calculates speed (or torque) error and stator flux error, compared to reference parameters. Consecutively, based on the aforementioned issues the most appropriate voltage vectors are attained to excite the stator phases. Ripples in speed and torque, are the main concerns, such methods try to deal with. In this paper, in addition to speed and flux errors, the speed variation slope is used as an auxiliary control parameter for a more precise speed control and decreasing speed ripples. The simulation results demonstrate a promising efficacy and accuracy of the proposed method. Keywords: PM-BLDC motors, Space Vectors Theory, Speed Control.

  3. IMPLEMENTATION OF BRIDGELESS CUK POWER FACTOR CORRECTOR WITH POSITIVE OUTPUT VOLTAGEDownload Article

    1K.Gayathri, 2K.Sathiyavani M.E.,

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    A single-phase, bridgeless Cuk AC/DC power factor correction (PFC) rectifier with positive output voltage is proposed in this paper. For low output voltage product applications, the rectifier is designed to convert high input voltage to low output voltage. Due to no bridge-diodes required and thus decreased input conduction losses, the proposed rectifier efficiency can be improved. The proposed rectifier operates in discontinuous conduction mode (DCM) and the current-loop circuit is hence not needed. Also, only a single switch is used in the rectifier to simplify the control circuit design. A simple translation method to have the positive output voltage in the Cuk converter is presented in the rectifier to reduce the component counts and the cost as well. The operational principles, steady-state analysis, and design procedure of the proposed rectifier are addressed in detail in this paper. Simulation and experimental results obtained from a 150 W-rated prototype circuit with input 90 Vrms -130 Vrms, 60 Hz, and output 48 Vdc have verified the validity of the proposed rectifier. Keywords: AC-DC power converters, voltage control, bridgeless, Cuk, PFC, DCM, positive output voltage, ZCS

  4. FUZZY CONTROL OF FOUR SWITCH THREE PHASE SEPIC BASED INVERTERSDownload Article

    1L.Malathi, 2Prof.R.Yalini M.E.,(Ph.D).,

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    The four-switch three-phase (FSTP) SEPIC inverter with fuzzy controller has been proposed as an innovative inverter design to reduce the cost, complexity, size, and switching losses of the DC-AC conversion system. Fuzzy conroller can generate five different PWM pulses. A novel design for the FSTP inverter based on the topology of the singleended primary-inductance converter (SEPIC). The proposed topology provides pure sinusoidal output voltages with no need for output filter. Compared to traditional FSTP inverter, the proposed FSTP SEPIC inverter improves the voltage utilization factor of the input DC supply, where the proposed topology provides higher output line voltage which can be extended up to the full value of the DC input voltage. Simulation model and experimental setup are used to validate the proposed concept. Simulations and experimental results show the effectiveness of the proposed inverter. Key terms — Four-switch three-phase inverter (FSTP), SEPIC converter, Fuzzy Logic Controller (FLC).

  5. GRID CONNECTED BOOST HALF BRIDGE PHOTOVOLTAIC MICRO INVERTER SYSTEM USING NEURO FUZZY CONTROLLERDownload Article

    1R.Divya, 2Prof.B.Gokulakrishnan M.E.,(Ph.D.,)

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    With the rapid development of large scale renewable energy sources and HVDC grid, it is a promising option to connect the renewable energy sources to the HVDC grid with pure DC system, in which high -power highvoltage step-up DC-DC converters are the key equipment to transmit the electrical energy. This paper proposes a resonant converter which is suitable for grid-connected renewable energy sources. The converter can achieve high voltage gain using LC parallel resonant tank. It is characterized by zero-voltage- switching (ZVS) turn-on and nearly ZVS turn-off main switches as well as zero-current-switching (ZCS) turn-off of rectifier diodes, moreover, the equivalent voltage stress of the semiconductor devices is lower than other resonant step up converters. The operation principle of the converter and its resonant parameter selection is presented in the paper. The operation principle of the proposed converter has been successfully verified by simulation and experimental results. Keywords: Resonant converter, Voltage step-up, Renewable energy, Soft Switching, Voltage Stress.

  6. EXPERIMENTAL ANALYSIS OF SOLAR AIR DRYER USING ROOF SHEET AS HEAT ABSORBER FOR CHILLI DRYDownload Article

    1K.Madhan, 2K.Mohankumar M.E., MBA.,

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    Drying of agro products in open air is reducing the quality losses. The direct sunlight drying process take long time and it’s subjected to attack by the weather, animals and insects. It’s also affect the quality, quantity and nutrition value of the food products. So use the solar dryer to dry the agricultural products. At, present renewable energies are increased energy efficiency play an important role in energy politics. Renewable energies are an important approach to reduce the environmental effect. So to use the solar energy to dry the agricultural products. This project aim is investigate the performance of solar dryer using semi-circular solar absorber with heat storing materials and thermal analysis of the solar absorber plate. This project designed such a way that solar radiation is not incident directly on the food product. The sunlight is absorb by the solar absorber (GI) plate, and heat is send through (GI) tube by forced convection and electric air blower to dry the agr icultural products in drying chamber. The (GI) is immersed in heat storing materials (charcoal or gravels).This heat storing materials store the heat at sun shining and transfer the heat to drying chamber to dry the agricultural products .

  7. Fused Multiply and Add Unit with Simulation and Verification ResultsDownload Article

    Jyoti Singh Chouhan, Nitin Jain

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    Floating point unit (FPU) is one of the most important custom applications needed in most hardware designs as it adds accuracy and ease of use. Recently, the floating point units of several commercials processors like IBM power PC; Intel/HP titanium, MIPS-compatible loongson-2F and HP PA-8000 have included a floating point fused multiply add (FMA) unit to execute the double –precision fused multiply add operation A+(B*C) as an indivisible operation, with no intermediate rounding.

  8. PERFORMANCE AND CHARACTERISTICS ANALYSIS OF FOUR STROKE SINGLE CYLINDER DIESEL ENGINE USING COTTON SEED OILDownload Article

    S.Megala, C.Thirunavukkarasu

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    Biodiesel, derived from the transesterification of vegetable oils or animal fats, is composed of saturated and unsaturated long-chain fatty acid alkyl esters as a renewable, sustainable and alternative fuel for compres sion ignition engine, biodiesel instead of diesel. The scope of the project is to find the engine performance and characteristics using biodiesel of cotton seed oil like Brake Power (BP), Specific fuel consumption (SFC), Brake Thermal Efficiency (BTE),indicated thermal efficiency and emission test. . The experiments are carried out with cotton seed oil biodiesel with different combinations like 15%, 25%.B15 blended fuel(15%cso+85%diesel) shows better performance which is very close to neat diesel fuel and also increases the BTE and reduces BSFC and having lower emission without any engine in design modifications. Keyword: Diesel engine, Alternative fuel, Performance characteristics, Cotton seed oil.

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