single-phase variable-frequency AC source

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A General Approach for Direct Conversion of Single Phase AC to AC Converter for Induction Heating System

A General Approach for Direct Conversion of Single Phase AC to AC Converter for Induction Heating System

The direct AC-AC converters also termed as Matrix Converters (MC) [5] when compared to DC link converters such as Voltage Source Inverters (VSI) and Current Source Inverters (CSI) possess more advantage such as wide range of operating fre- quency, variable output voltage magnitude for a given fixed frequency [6] and fixed voltage input supply without any intermediary DC link due to direct conversion of AC-AC, which is highly advantages for these type of converters over other conventional converter and the development of fast and efficient switching devices such as SCR, GTO, MOSFET and IGBT’s paved way for using these AC-AC converters in practice effectively [7]. In this article a Single Phase Matrix Converter (SPMC) controlled by a PID controller is employed to supply an Induction Heating (IH) system. The operation of the proposed controlled SPMC and the performance of the system over different op- erating frequencies is revealed in detail [8] [9].
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Simulation and Modeling of Single Phase DC AC Converter of Solar Inverter

Simulation and Modeling of Single Phase DC AC Converter of Solar Inverter

There are two types of inverters. 1. VSI (voltage source inverter) 2. CSI (current source inverter). Here we are using VSI. A voltage source inverter (VSI) is one that takes in a fixed voltage from a device, such as a dc power supply, and converts it to a variable-frequency AC supply. Also it easier to convert AC voltage from DC voltage. A solar inverter is a power-electronic circuit that converts dc voltage from a solar array panel to ac voltage that can be used to power ac loads such as home appliances, lighting and power tools. However, getting the most out of such a topology requires careful analysis and the right choice of the high-side and low-side combination of an IGBT. According to our requirement, here we consider single phase 2 Arm Bridge – 4 pulse converter for solar inverter.
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Single Phase Variable Voltage Variable Frequency Pure Sine Wave Inverter

Single Phase Variable Voltage Variable Frequency Pure Sine Wave Inverter

2012 A sinusoidal power source is developed. The MOSFET H bridge inverter is used. The voltage and frequency is varying in an ac voltage range of 30–80Vrms and a frequency range of 40–70Hz. The SPWM is used in which constant amplitude pulses are

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Asymmetric Three Phase Cascading Trinary DC Source Multilevel Inverter Topologies for Variable Frequency PWM

Asymmetric Three Phase Cascading Trinary DC Source Multilevel Inverter Topologies for Variable Frequency PWM

The design and implementation of cascaded multilevel inverter [16] is operating in current mode. The Neutral Voltage Modulation technique for multilevel cascade inverters under unbalanced dc-link conditions has been proposed in [17]. A novel single-phase five-level multilevel inverter proposed in [18] produces a five-level out- put voltage with only one DC source using coupled inductors [18]. A new technology of an improved PWM to- pology for chopper-cell-based modular multilevel converters is established in [19]. A latest converter configura- tion based on cascaded converter family unit is offered [20]. The recommended multilevel highly developed cascaded converter has settlement such as lessening in number of power semiconductor switches and its losses [20]. A generalized power loss algorithm for multilevel neutral-point clamped pulse width modulation technique is offered, which is appropriate to any level number of multilevel inverter [21]. A fifteen-level photovoltaic fed cascade multilevel inverter for the removal of certain harmonic orders is urbanized for the power quality devel- opment [22]. Fresh topologies for a cascade transformer sub-multilevel inverter with every sub-multilevel in- verter consists of two DC voltage source with six power semiconductor switches to attain five-level output vol- tage [23]. An asymmetrical cascaded half-bridge multilevel inverter for 3 hp fuel cell electric vehicle (FCEV) with Direct Torque Control-Space Vector Modulation scheme (DTC-SVM) based electric drive (induction mo- tor) has been implemented in [24].
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A single phase bidirectional AC/DC converter for V2G applications

A single phase bidirectional AC/DC converter for V2G applications

In [18,19] a dual active-bridge (DAB) converter is considered due to its simple topology and good output waveforms, but the current in the circulation process is high. In [20], a converter consisting of a single-phase current-source rectifier and an auxiliary switching network is proposed. It has high efficiency and offers bidirectional power flow. However, the circuit of the proposed topology is complex and the output current ripple is still large, which may reduce the battery life. Furthermore, all the converters mentioned above have no focus on reactive power compensation capability. To realize the reactive power operation, single-phase, on-board, bidirectional plug-in electric vehicle (PEV) chargers have been introduced [21]. The topology of the charger contains several characteristics such as simple structure, convenient control, and practicable construction. However, all the switches are operated at high frequency, which increases the power loss.
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Power Factor Correction in Single Phase AC-DC Converter

Power Factor Correction in Single Phase AC-DC Converter

Switched-mode power supplies employ either variable switch duty cycle or variable switching frequency (occasionally both) associated with feedback circuitry to provide the required output voltage and output current. Today it is possible to design variety of pfc circuit with different modes of operation. There exist two mode of operation discontinuous and continuous. Here didode bridge rectifier act as non linear load and because of non linear load there is distortion in input current. Buck-boost converter in discontinuous inductor current mode is studied and simulated. The peak current control technique for continuous conduction mode is studied and simulated in MATLAB beacause it allows low THD input current and unity power factor. The MATlab/Simulink results of peak current control technique comply with IEEE 519-1992 standard.
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A Transient Performance analysis for Vector
Controlled z-source Inverter fed Induction
Motor Drive

A Transient Performance analysis for Vector Controlled z-source Inverter fed Induction Motor Drive

Suitability of any drive for an application depends on its behavior under transient and steady state conditions. To study the behavior a MATLAB/Simulink model is developed to examine the transient performance of the induction motor drive. The simulations use the parameters of the 1.5 hp 50 Hz induction motor. The schematic block diagram of complete drive system is shown in Figure 3. The vector controlled Z-source inverter-fed induction motor drive consists of a three- phase AC source, a three-phase diode rectifier, a Z-source inverter and a three-phase squirrel cage induction motor with load. The vector control block consist of PI speed controller, theta calculation block ABC to d-q transformation block, I d *
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DESIGN AND SIMULATION OF GRID CONNECTED PV FED SINGLE  PHASE INVERTER WITH CLOSED LOOP BOOST CONVERTER.

DESIGN AND SIMULATION OF GRID CONNECTED PV FED SINGLE PHASE INVERTER WITH CLOSED LOOP BOOST CONVERTER.

Solar energy is considered as fastest growingrenewable energy source after wind energy for electricity generation. Solar energy is a free, clean abundant sun energy considered as inexhaustible source for electricity generation. Solar photovoltaic system is characterised with variable output power due to its operation dependency on solar irradiance and cell temperature. To maximize the energy generation potential of solar PV, research effort is focused on solar cell manufacturing technology to increase its generation efficiency and exploring advancement in power electronic devices for small and large scale deployment. Presented in this paper is a single phase inverter with no transformer for solar PV application. A closed loop DC-DC boost converter that accepts wide input DC voltage from 40 V – 60 V to produce constant 330 V DC voltage is modelled in Matlab/Simulink. An H-bridge 2-level inverter was used to convert the DC voltage to chopped AC voltage which was then filtered to give pure sinusoidal AC of 230 V RMS. The output voltage of the inverter has a very low total harmonic distortion of less than 1 % which makes the system suitable for local AC load and grid connection.
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Low Power AC-DC and DC-DC Multilevel Converters

Low Power AC-DC and DC-DC Multilevel Converters

The main focus of this thesis is on development of new and improved AC-DC single-stage converters that are based on multilevel circuit structures (topologies) and principles instead of conventional two-level ones. The development of a new DC-DC multilevel converter is a secondary focus of this thesis. In this thesis, a literature survey of state of the art AC-DC and DC-DC converters is performed and the drawbacks of previous proposed converters are reviewed. A variety of new power electronic converters including new single-phase and three-phase converters and a new DC-DC converter are then proposed. The steady-state characteristics of each new converter is determined by mathematical analysis, and, once determined, these characteristics are used to develop a procedure for the design of key converter components. The feasibility of all new converters is confirmed by experimental results obtained from proof-of-concept prototype converters. Finally, the contents of the thesis are summarized and conclusions about the effectiveness of using multilevel converter principles to improve the performance of AC-DC and DC-DC converters are made.
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Design of 50KVA Single Phase Static Inverter

Design of 50KVA Single Phase Static Inverter

The design and implementation of a single-phase inverter that produces a symmetric ac output voltage of desired magnitude and frequency. The digital signal Peripheral Interface Controller of Microchip Technology is used for the implementation of the inverter. The Inverter consists of four bidirectional switches that is used to convert the voltage. Sinusoidal Pulse Width Modulation is used for triggering the gates of IGBTs. The control circuit consists of the PIC controller that is used to produce required PWM signal. The voltage and the frequency can be varied by connecting the controller to the computer. The simulation of the circuit is done using Simulink of Matlab. The outputs for variable AC voltages are observed in the CRO with comparison of the standard values against those of Simulation waveforms and the output waveforms.
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DIRECT AC TO AC CONVERTER WITH VARIABLE FREQUENCY SINUSOIDAL CURRENTS FOR APPLICATION TO GRID CONNECTED WIND GENERATORS

DIRECT AC TO AC CONVERTER WITH VARIABLE FREQUENCY SINUSOIDAL CURRENTS FOR APPLICATION TO GRID CONNECTED WIND GENERATORS

AC to AC Matrix Converter having a nine switch topology with hysteresis controller is analyzed in this paper using MATLAB/SIMULINK package. A Matrix Converter with 18 IGBTs and 18 diodes achieves the desired variable voltage, variable frequency performance using a two stage circuit. In the first stage three phase normal frequency voltage is converted to single phase high frequency voltage. In second stage three phase variable amplitude variable frequency voltage is generated. Hysteresis controller is implemented to obtain sinusoidal output current.In this paper output frequency realized is 50 Hz. It is possible to set the output to any other frequency also.
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Single Stage Single Phase Reconfigurable Inverter Topology

Single Stage Single Phase Reconfigurable Inverter Topology

Now a day, Electricity is becoming very essential for survival. The consumption of electricity is increasing due to increasing population. Because of increasing load demand, the various electricity board doesn’t able to fulfill the Load Demand. So gap between generation side and utility side is increasing. To Overcome the Gap between generation side and utility side Now a day Renewable Energy Source, such as photovoltaic, Wind power, etc are very much Popular. Most of the load used by consumes are AC, which cause Harmonic loss. These harmonic losses affect the whole system. It causes decreasing efficiency as well as Power Quality of the system. Hence performance of the whole system Decreases. Most of the devices used in domestic loads are work on DC supply, but supply provided by the grid is AC. It is then rectified to DC at required value and provided to the various devices. At this junction, major losses are occurs, which cause harmonic current and this harmonic current affect voltage coming from supply resulting voltage fluctuation and voltage harmonic. Due to increasing Non-linear household equipments, harmonic loss increases; so we need to improve power quality by reducing harmonics.
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Preparation and Characterization of New Oxide Ion Conductors in Bi2O3-As2O5 System

Preparation and Characterization of New Oxide Ion Conductors in Bi2O3-As2O5 System

XRD shows that single phase materials were formed when x = 5, 5.5, 5.667, 5.75, 6 and 7. The symmetry and space group of the materials were determined. Compositions with 5 ≤ x ≤ 6.25 are solid solutions. Electrical properties of the single phase materials were studied using ac impedance spectroscopy at a frequency range of 10 Hz to 13 MHz. These materials are thermally stable and appear to be oxide ion conductors. Highest conductivity was obtained in Bi 23 As 4 O 44.5 with σ value of 5.66 x 10 - 5 ohm -1 cm -1 , E
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power quality improvement using D-STATCOM

power quality improvement using D-STATCOM

The renewable energy resources like wind, biomass, hydro, co-generation are necessary to meet the energy need in sustainable growth and social progress. To integrate the wind energy into the power system to make it possible to minimize the environmental impact on conventional plant. Wind turbine transform the energy in the wind into the mechanical power which can be converted into the electrical power to generate the electricity [1]. These power variations are caused by the effect of turbulence, wind shear, and tower shadow. One of the simple method of running a wind energy system is to use the induction generator and it’s directly connected to the grid system. The wind energy system present a technical challenges like stability, voltage regulation, and power quality issues [2]. The power quality is affected by the operation of transmission and distribution side in the grid. The power quality issue is the most important to the wind turbine. The power quality issues such as voltage sag, voltage swell, voltage fluctuation/ voltage flicker, voltage unbalance, harmonics etc. One of the most important Power Quality Issue in grid is voltage sag (voltage dip). The voltage sag is short duration of reduction in r.m.s voltage. Its range between 10% to 90 % of nominal voltage and with duration from half a cycle to 1 min. Voltage sag caused due to a fault in the utility system, a large increase of the load current like a starting the motor or transformer energizing [3]. There are different ways to mitigate the power quality issue in transmission and distribution system. A wide range of very flexible controllers like power electronics components are emerging for custom power application [4]. The Distribution Static Compensator (D- STATCOM) are most effective device based on Voltage Source Converter (VSC). STATCOM is usually used in transmission system while D-STATCOM is used in distribution system however it’s called as the Distribution Static Compensator (D- STATCOM). D-STATCOM is utilizes power electronics to solve many power quality issues by distributed system. D- STATCOM used to improve the voltage regulation, load balancing, power factor correction and harmonics etc. D-STATCOM and STATCOM are used to different control strategy. The use of STATCOM is wide and its control strategy is mature wherever the introduction of D-STATCOM is seldom reported. Many control techniques such as Instantaneous Real and Reactive Power Theory (IRP) from H. Akagi and power balance theory etc. There is Instantaneous Real & Reactive Power Theory (IRP) are used. To obtained the gating pulses for the Insulated Gate Bipolar Transistor (IGBT) devices used in Current Controlled Voltage Source Converter (CC-VSC) working as D-STATCOM. The control scheme of D-STATCOM with connected wind energy system is simulated using MATLAB/SIMULINK.
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Suppression of Double-Frequency Ripple with Fuzzy Control Based Single-Phase Pv Quasi-Z-Source Inverter

Suppression of Double-Frequency Ripple with Fuzzy Control Based Single-Phase Pv Quasi-Z-Source Inverter

and improve the efficiency . In order to prevent the ripple energy flowing into the input PV side, a modified modulation and an input DFR suppression controller are used to decouple the input voltage ripple from the qZS capacitor DFR. The small signal model is developed and shows that the capacitance reduction does not impact the system stability. In this paper capacitance reduction control strategy is proposed to buffer the DFR energy in Z source or Quasi Z source inverter application. The proposed control strategy can significantly reduced the capacitance requirement without using any extra hardware component. This can also achieve low input voltage DFR. Consequently a highly reliable film capacitors can used.
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A Closed Loop Controlled Three Phase Single Stage PFC AC–DC Converter for Variable Voltages
Y Shashidhar & Naresh Bandi

A Closed Loop Controlled Three Phase Single Stage PFC AC–DC Converter for Variable Voltages Y Shashidhar & Naresh Bandi

Mode 3(t2<t<t3)[Fig. 4(c)]: In this mode,S1 and S2 are OFF. The energy stored inL1still is transferring into the dc bus capacitor. The primary current of the transformer charges C2 through the body diodes of S3and S4. Switch- es S3andS4are switched ON at the end of this mode. Mode 4(t3<t<t4) [Fig. 4(d)]: In this mode, S3 andS4 are ON, and the energy flows from capacitor C2 into the load. The voltage appears across auxiliary winding 2 which is equal to the dc bus voltage but acts like a magnetic switch and cancels out the dc bus voltage. The voltage across the boost inductors L2(L2=Labc2)becomes only the recti- fied supply voltage of each phase, and the current flowing through each inductor increases. This mode ends when the energy stored inL1completely transfers into the dc bus capacitor. For the remainder of the switching cycle, the converter goes through modes 1–4 but with S3andS4 ON instead ofS1andS2and with DB2instead of DB1.
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Advanced Rectifier Topology with Variable Speed High Power PMSG Wind Turbine with Filter Scheme

Advanced Rectifier Topology with Variable Speed High Power PMSG Wind Turbine with Filter Scheme

Various power-converter topologies were presented in the literature for direct-drive PMSG based wind turbine [2],[5]. The most popular topology in variable-speed wind turbines is the back-to-back two-level VSC [3], [5]; to use it in higher voltage systems, however, requires the series connection of active switches and brings about the device voltage sharing issue. As alternative solutions, back-to-back multilevel VSCs such as three-level neutral-point-clamped converter [3] and multimodular cascaded H- bridge converter [4] have been proposed. Comparing to the two-level VSC, the multilevel converters enable the use of low-voltage devices and provide better waveform quality. What should also be mentioned is that, in addition to VSCs, the possibility of using medium-voltage back-to-back CSC for high-power PMSG based wind turbines. All the aforementioned converters employ pulse width modulation (PWM) in both the rectifier and the inverter, achieving torque/speed control on the generator side, while providing sinusoidal voltage and current waveforms on the grid side. Instead of back-to-back PWM converters that involve numerous expensive active power switches and complex control, an uncontrolled diode rectifier can be used as the generator-side rectifier to save cost [5]. Due to the lost control flexibility in the rectifier, the grid-side inverter, either a voltage-source inverter (VSI) or a current source inverter (CSI) has to be employed [3] to provide control over the dc stage to regulate the generator speed. The CSI solution in requires an active filter to improve grid-side harmonic profile if dc current and grid power factor are both to be regulated. In the case of a VSI, the inverter needs to be oversized to ensure proper power capture at low wind speeds, which significantly increases the overall cost in a large wind turbine. Adding a dc–dc boost converter between the diode rectifier and the VSI can avoid this problem; however, additional control and power losses are introduced that somewhat offset the obtained benefits. This paper presents advanced rectifier topology for variable speed high-power PMSG wind turbines with filters. Employing only diodes and naturally commutated thyristors, the proposed rectifier features low cost, low power loss and high reliability. It can work with non oversized PWM-VSI and is able to perform torque/speed control on the generator to capture maximum input power from varying wind speed. Also by using shunt inductors as a filter, the resultant torque ripple and harmonic losses in the generators are much reduced [6].
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Speed Control and Power Factor Improvement of a Single Phase AC Motor

Speed Control and Power Factor Improvement of a Single Phase AC Motor

design aims to monitor the phase angle continuously and in the event of phase angle deviation, a correction action is initialized to compensate the difference by continuous changing variable capacitor value via a switching process. The motor was used as a medium to show that the power factor can be controlled using the PLC. In the proposed method, the PLC senses any changes occur in the speed of motor. Then, accordingly, it turns ON or OFF capacitors in the capacitor bank (i.e., depending on the speed of motor either increasing or decreasing). In this way, we maintain the power factor value at a desired level. The power factor remains same no matter how many motors turned ON or OFF. The overall system requires only one microcontroller chip, some power electronic components, capacitor bank and a PLC unit for switching purpose.
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Analysis of Variable Frequency Three Phase Induction Motor Drive

Analysis of Variable Frequency Three Phase Induction Motor Drive

The pulse width modulated (PWM) inverter for variable speed drive of induction motor circuit drives small induction motors up to about 0.5 horse power, 380 volts, variable frequencies. The frequency may be adjusted from 16 Hz to 60 Hz. So, the motor speed can be varied from 464 rpm to 1740 rpm. The complete system of this thesis consists of an AC voltage input that is put through a diode bridge rectifier to produce a DC output which across a shunt capacitor, this will, in turn, feed the PWM inverter. The PWM inverter is controlled to produce a desired sinusoidal voltage at a particular frequency to the squirrel cage induction motor.
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I NTERNATIONALJ OURNAL OF ENGINEERINGS CIENCES & MANAGEMENT Review of reduce component count in nine level inverter employed single bi- directional switching for transformer

I NTERNATIONALJ OURNAL OF ENGINEERINGS CIENCES & MANAGEMENT Review of reduce component count in nine level inverter employed single bi- directional switching for transformer

Multilevel inverters have created a new wave of interest in industry and research. While the novel topologies have proved to be a viable alternative in a wide range of high-power medium-voltage applications, there has been an active interest in the evolution of newer topologies. Reduction in overall part count as compared to the classical topologies has been an important objective in the recently introduced topologies. In this paper, the proposed multilevel inverter topologies with reduced power switch count are analyzed. A novel cascaded transformer multilevel inverter is proposed. The number of the switching devices is reduced in the proposed topology. This topology comprises of a DC source, several single phase low-frequency transformers, two main power switches and some bidirectional switching devices. In this topology, only one bidirectional switch is employed for each transformer.
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