The consequence of simulation shows that the two control strategies achieve power factor correction and harmonic reduction requirements; Boost type power conversion circuit employs the a[r]

In a purely resistive AC **circuit**, voltage and current waveforms are in step (or in phase), changing polarity at the same instant in each cycle. Where reactive loads are present, such as with capacitors or inductors, energy storage in the loads result in a time difference between the current and voltage waveforms. This stored energy returns to the source and is not available to do work at the load. A **circuit** with a low **power** **factor** will have thus higher currents to transfer at a given quantity of **power** than a **circuit** with a high **power** **factor**.

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Schematic diagram of a three level voltage source inverter fed PMBLDC motor with PFC full bridge converter is shown in Fig.1.This is a closed loop control **circuit** using 3 Hall Sensors. MOSFETs are used as switching devices here. For very slow, medium, fast and accurate speed response, quick recovery of the set speed is important keeping insensitiveness to the parameter variations. In order to achieve high performance, many conventional control schemes are employed. At present the conventional PI controller handles these control issues. Moreover conventional PI controller is very sensitive to step change of command speed, parameter variation and load disturbances.

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The Interleaved **Boost** PFC rectifier with high gain output voltage has been proposed and experimentally verified. The experimental results have shown good agreements with the predicted waveforms analyzed in the paper. The **power** **factor** of the **circuit** has at all the specified input and output conditions. Satisfaction of the requirements can be easily achieved by the proposed **circuit**. Moreover, with higher efficiency and high **power** **factor** the proposed topology is able to be applied to most of the consumer electronic products of 150W rating in the market. Also, with only a single switch employed, the implemented system control **circuit** is simple to achieve high **power** **factor** by applying any PWM control.

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This paper presents a single phase **power** **factor** **correction** converter implementing an active snubber **circuit** and a dual mode controller. This new PFC is realized with a 200V ac input to provide a 400V dc output. This PFC consists of a main switch that is turned ON by ZVT and turned OFF by ZCT and an auxiliary switch that has ZCS turn ON and turn OFF. The active snubbercircuit provide soft switching to the main and auxiliary switches, thus eliminating the voltage and current stresses on the main switch. The voltage stresses on the auxiliary switch is also eliminated, but the current stresses exists which can be reduced by transferring these stresses to the output load by coupling inductance. The dual mode control method combines both CCM and CRM and it provides high **power** and efficiency at light-load conditions. The dual-mode controller of the **boost** PFC is particularly suitable for a fixed frequency **boost** PFC controller the dual mode control **circuit** is simple and easy to implement in the IC without much additional space and cost. The overall efficiency and optimum **power** **factor** is obtained at both light-load and heavy-load conditions.

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ABSTRACT: Thestrategyusually used in manufacturing, commercial and residential applications need to go throughadaptationdesigned for their suitableimplementation and operation. They are coupled to the grid comprising of non-linear loads and thus have non-linear input characteristics, which results in production of non-sinusoidal line current. Also, current comprising of frequency components at multiples of line frequency is observed which direct to line harmonics. Due to the increasing insist of these strategies, the line current harmonics create a keydifficulty by degrading the **power** **factor** of the system thus disturbing the performance of the strategy. Hence there is a require to reduce the line current harmonics so as to get better the **power** **factor** of the system. This has lead to designing of **Power** **Factor** **Correction** circuits.Power **Factor** **Correction** (PFC) involves two techniques, Active PFC and Passive PFC. In our systemexertion we contain designed an active **power** **factor** **circuit** using Buck Converter for improving the **power** **factor**. Average Current Mode Control method has been implemented with buck converter to check the effect of the active **power** **factor** corrector on the **power** **factor**. The assistance of using Buck Converter in **power** **factor** **correction** circuits is that enhanced line regulation is obtained with substantial **power** **factor**. The proposed concept can be implemented to DC motor drive Applications for two switch buck **boost** converter by using mat lab/Simulink software.

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ABSTRACT: Design and implementation of **boost** and Interleave **Boost** Converter ((IBC) with Proportional and Integral (PI) average current control method for **Power** **Factor** **Correction** (PFC) is presented. The **Power** **Factor** (PF) is increased significantly with reduction in total harmonic distortion (THD), current ripple and voltage ripple by integrating the IB converter into the full bridge diode rectifier. The proposed PI average current control method is based on sensing of the input current which can easily be accomplished by using unidirectional current transformer. The full bridge **Boost** and IB converter with pulse width modulation based on multiplier **circuit** is analysed as it enhances the voltage gain with reduction in voltage stress of semiconductors in the **boost** and IBC rectifier **circuit**. Hence High efficiency is achieved with low voltage rated MOSFETs and diodes. Control characteristics and performance of the IB converter is analysed using state space model and verified by a measurement result from a 1500W model. Operation of the converter with variable switching frequency (25 KHz -100 KHz) and variable load (50 Ω -200Ω) is reported.

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According to Fig.2, low pass filter, Re1 and Ce1, Re2 and Ce2 are used to filter inductor freewheeling current sense signal on Rs1 and Rs2. Due to low frequency (2fL) ripple on Rs1 and Rs2, the time constant of these low pass filters should be lower than 1/2fL. The capacitance and resistance of these two filters are designed as 100nF and 120k_ in this prototype. Two compensators (Op1, Re3, Ce3, Op2, Re4 and Ce4) are applied to achieve sufficient phase margin and low bandwidth for **power** **factor** **correction**. Fig.10 shows the loop gain of Psim simulation results at 100Vac for sub-converter A with different compensation parameters (_1, _2 and _3) by using the **circuit** parameters shown in Table I. It can be observed that when time constant _ =Re3Ce3 is lower than 0.22ms, the phase margin is approximately 90 degree when the compensator is applied. The bandwidth will be lower than 20Hz, which can ensure acceptable **power** **factor** **correction** requirement, but

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An analysis of **boost** converter **circuit** revealed that the inductor current plays significant task in dynamic response of **boost** converter. Additionally, it can provide the storage energy information in the converter. Thus, any changes of inductor may effect output voltage and output voltage will provide steady state condition information of converter. However, the three main parameter need to be considered when designing **boost** converters are **power** switch, inductor and capacitor. In this objective to achieve the desired output voltage[9].

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ABSTRACT:The devices generally used in industrial, commercial and residential applications need to undergo rectification for their proper functioning and operation. They are connected to the grid comprising of non-linear loads and thus have non-linear input characteristics, which results in production of non-sinusoidal line current. Also, current comprising of frequency components at multiples of line frequency is observed which lead to line harmonics. Due to the increasing demand of these devices, the line current harmonics pose a major problem by degrading the **power** **factor** of the system thus affecting the performance of the devices. Hence there is a need to reduce the line current harmonics so as to improve the **power** **factor** of the system. This has led to designing of **Power** **Factor** **Correction** circuits.Power **Factor** **Correction** (PFC) involves two techniques, Active PFC and Passive PFC. In our project work we have designed an active **power** **factor** **circuit** using Buck Converter for improving the **power** **factor**. Average Current Mode Control method has been implemented with buck converter to observe the effect of the active **power** **factor** corrector on the **power** **factor**. The advantage of using Buck Converter in **power** **factor** **correction** circuits is that better line regulation is obtained with appreciable **power** **factor**. The proposed concept can be implemented to DC motor drive Applications for two switch buck **boost** converter by using mat lab/Simulink software.

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For a purely resistive **circuit**, the PF is 1 since the reactive **power** equals zero. For a purely inductive **circuit**, the PF is zero since true **power** equals zero. Same for a purely capacitive **circuit**. Thus, if there are no dissipative (resistive) components in the **circuit**, the true **power** must be zero, making any **power** in the **circuit** purely reactive. PF is an important aspect to consider in an AC **circuit**; because any **power** **factor** less than 1 means that the circuit’s wiring has to carry more current than what would be necessary to deliver the same amount of (true) **power** to the resistive load. Thus, the poor **power** **factor** indicates an inefficient **power** delivery system. Poor PF can be corrected by adding another load to the **circuit** drawing an equal but opposite amount of reactive **power**, to cancel out the effects of the load’s inductive reactance. Inductive reactance can only be canceled by capacitive reactance, so we have to add a capacitor in parallel to the **circuit** as additional load. The effect of these two opposing reactance in parallel is to bring the circuit’s total impedance equal to its total resistance (to make the impedance phase angle equal, or at least closer, to zero).

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A. Dual **boost** converters: **Boost** converters are used as active **power** **factor** correctors. However, a recently PFC is to use dual **boost** converter (Fig.2) i.e. two **boost** converters connected in parallel. Where choke Lb1 and switch Tb1 are for main PFC while Lb2 and Tb2 are for active filtering, the filtering **circuit** serves two purposes i.e improves quality of line currents and reduces the PFC total switching loss. The reduction in switching losses occurs due to different values of switching frequency and current amplitude for the two switches.

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The objective of this project work is to develop a Buck-**Boost** Converter to achieve high **power** **factor** with high operating frequency with simulation study. The recent technologies which involve high frequency applications such as wireless **power** transfer (WPT) use a high operating frequency in the range from a few hundred of kHz to over some of MHz. Such buck, **boost** or buck-**boost** conﬁguration adopt improved **power** quality in terms of reduced total harmonic distortion (THD) of input current, **power**-**factor** **correction** (PFC) at AC mains and precisely regulated and isolated DC output voltage feeding to loads from few Watts to several kW. Further this paper presents a comprehensive study on **power** **factor** corrected single-phase AC-DC converter conﬁguration, control strategy and design considerations, **power** quality considerations, latest trends, potential applications and future developments. Simulation results as well as comparative performance are presented and discussed for such proposed topology.

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However, as switching frequency increases, the output diode operating at dc-link voltage produces significant reverse-recovery losses that appear as additional turn-on losses along with the increased switching loss in the **circuit** [3]. The auxiliary ZVT concept was first presented in [4], where a switch, a diode, and an inductor are implemented to achieve the lossless switching transition. A review of unidirectional as well as bidirectional single-phase PFC rectifier topologies with improved **power** quality is presented in [5], where the most popular and widely used topology is a **boost**-type PFC which consists of a diode bridge followed by **boost** **circuit**. To achieve high **power** density and faster transient response, the **boost** PFC is pushed to operate at high switching frequencies. A family of self-commutated auxiliary circuits is used to minimize these problems. These converters achieve zero current switching (ZCS) in the additional switch but experience higher voltage stresses in their passive components. A family of bridgeless PFC **circuit** having coupled inductors to ensure ZCT in the auxiliary switch was proposed in [6]. Also, a bridgeless PFC without additional voltage and current stresses in the auxiliary device was proposed in [7]. The main drawback of this converter is that the auxiliary switch is turned OFF while it is conducting current. Due to hard-switching losses, we don’t get the benefits gained with the auxiliary **circuit**. Converters in [8] and [9] use a dissipative snubber **circuit** to limit these losses but the auxiliary switch still operates in a hard-switched condition. The auxiliary inductor and the auxiliary diode are in series with the **boost** diodes thereby carrying the full-load current and adding to the conduction losses.

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A two-limb parallel connected conventional **boost** converter is shown in Fig.4 this is typically called an interleaved **boost** converter. This converter is used to improve **power** **factor** For a step-up application, an equivalent interleaved **boost** converter offers several advantages over a conventional **boost** converter; such as a lower current ripple on the input and output stages. Therefore, there is there is the opportunity to minimise the output capacitor filter that is often quite large in the conventional **boost** . In addition, it effectively increases the switching frequency without increasing the switches losses. Furthermore, it provides a fast transient response to load changes and improves **power** handling capabilities. A higher efficiency may be realized by splitting the input current into two paths, substantially reducing i 2 R losses and inductor AC losses. This also gives low stresses on components due to the current split which increases the **power** processing capability [9]. However, using an interleaved converter increases the number of **power** handling components and **circuit** complexity which may lead to an increase in cost. However, in renewable energy systems, long-term improved **power** generation can help to offset this disadvantage [9]. The topology of the interleaved **boost** converter consists of two limbs operating at 180 degrees out of phase from each other. Typically, each branch operates in the same fashion as a conventional **boost** converter previously described in Chapter four. When S1 turns on, the current ramps up in L1 with a slope depending on the input voltage storing energy in L1, D1 is off during this time since the output voltage is greater than the input voltage. When S2 turns off, the L2 inductor delivers part of its stored energy to output capacitor and the load, the current in L2 ramps down with a slope dependent on the difference between the input and output voltage. One half of a switching period later, S2 also turns on, completing the same cycle of events

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Thus, in each half line cycle, one of the MOSFET operates as an active switch and the other one operates as a diode. The difference between the bridgeless PFC and conventional PFC is that in bridgeless PFC converter the inductor current flows through only two semiconductor devices, but in conventional PFC **circuit** the inductor current flows through three semiconductor devices. The two slow diodes of the conventional PFC converter are replaced by one MOSFET body diode in bridgeless PFC converter. Since both the circuits operates as a **boost** DC/DC converter; the switching loss of the converters are same. Thus, the efficiency improvement in bridgeless PFC converter relies on the conduction loss difference between the two slow diodes and the body diode of the MOSFET. The bridgeless PFC converter also reduces the total components count as compared to a conventional PFC converter.

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Energy conservation is the world's most urgent work at present. This study focuses on the research and development of the AC-DC conversion **circuit** for variable frequency control, which is closely related to human life. It uses the bridgeless rectifier **circuit**, coupled with the Interleaved **Boost** and “PFC” (**Power** **Factor** **Correction**) technology to design a high-efficiency AC/DC conversion **circuit**. In electrical engineering, the **power** **factor** of an AC electrical **power** system is defined as the ratio of the real **power** flowing to the load to the apparent **power** in the **circuit**, and is a dimensionless number in the closed interval of −1 to 1.In **power** system **power** **factor** (p.f) is an important **factor** of continuous quality electrical supply some time it reduces due to some reactive **power** disorder **power** **factor** affected and by hence the quality (voltage and efficiency) also affected. There are many methods to improve the **power** **factor** such as capacitor bank, synchronous condenser, thyristor controlled rectifier(TCR) etc. But they have losses problem so a new technique is introduced three level single inductor bridge less **boost** **power** **factor** **correction** rectifier with voltage clamp property by the MATLAB simulation technique it used bridge less three level **boost** topology. It consist of two different types of diode, i.e fast diode & slow diode , MOSFET, capacitor & inductor due to use of semiconductor device soft switching it has high efficiency, low device voltage stress as well as high Voltage gain. With the help of MATLAB simulation four modes of operation is processed these are (a).Charging stage in the positive half cycle and (b).discharging stage in positive half cycle (c).Charging stage in the negative half cycle and (d). Discharging stage in negative half cycle and the whole improved **power** **factor** supply is obtained in the wave form. And this output is to give the feasible input to the other electrical device such as electrical motor. It can be used in UPS for regular **power** supply.

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the semiconductor device results in reverse recovery losses and electromagnetic interference problems. In recent years, many soft-switching techniques have come forth to reduce the adverse effects of conventional **boost** **power** **factor** **correction** converters. Soft-switching techniques, especially zero-voltage-transition have become more and more popular in the **power** supply industries. These converters have an auxiliary **circuit** connected in parallel to the main switch to help it turn on with zero-voltage-switching. ZVT converters operate at a fixed frequency while achieving zero voltage turn-on of the main switch and zero current turn-off of the **boost** diode. This is accomplished by employing resonant operation only during switch transitions. During the rest of the cycle, the ZVT network is removed from the **circuit** and converter operation is identical to conventional **boost** converter [3].

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