Active And Passive Snubber Based Dc Converter

ABSTRACT- D.C. motors are seldom used in ordinary applications because all electric supply companies furnish alternating current. However, for special applications such as in steel mills, mines and electric trains, it is advantageous to convert low value of DC into high value of DC in order to use D.C. motors controlled by power electronic apparatus. Here the DC motor is controlled power electronic converters through RES system. Although the design of these converters has been presented at the operational level, some fundamental issues such as topologies, analyses, and control have not been thoroughly studied. In this paper, the basic HB TL topology is first presented. This is followed by the derivation of a systematic method of generating TL converter topologies, leading to the derivation of a family of TL converters with improvement and simplification for better functionality and practicality. This paper discusses wide range soft switching solutions to a pulse width

Now a days, the switching power supply market is flourishing quickly. The trend is for DC-AC converters with low cost, higher efficiency, power saving that enable maximum features. In this project, a single-stage three-switch buck-boost inverter is designed, where stepping up, stepping down and inversion operation will takes place in single stage. This proposed inverter will overcome all the drawbacks of traditional one. Coupled inductor plays a very important role in energy transfer and eliminates the use of line frequency transformer. As the inverter having only three switches, the controlling of switches also easier than conventional one. And it has also advantages like compact design, reduced switching losses, component size, and cost.

D.C Motor is used for variable speed operation because in dc motor torque and flux that can be control independently and that is achieved by armature and field current control respectively. D.C motor has many advantages delivering high starting torque, ease of control and non linear performance. But due to certain disadvantage of dc machine such as mechanical commutator and brush holder required time to time maintenance [1] .So cost of the drive system is increases. But now D.C Motor is less used in industrial applications. Because of low cost, better performance and the requirement of maintenance is less as compared to D.C Motor it make the asynchronous motor advantageous in many industrial applications. SCIM are most widely used than all the rest of the electric motor as they have all the advantages of A.C Motors and are cheaper in cost as compared to slip ring induction motor. Because of absence of slip rings, brush maintenance duration and cost associated with the wear and tear of brush are minimized. Because of these advantages, the induction motor is used in element of most of the electrical drive system for all the conditions like starting, braking, change in speed and speed reversal. To achieve the maximum efficiency of the induction motor drive, so many techniques are developed in the last few years. Now a day’s high switching frequency converters are used for changing the frequency, phase and amplitude of the input to an A.C. Motor can be changed, hence the speed and motor torque can be controlled. With the help of power electronic it is possible to

Abstract— this paper presents a brief overview of standards for power electronics. All the standards presented in this paper are currently active and are approved by the Institute of Electrical and Electronics Engineer Standards Association (IEEE-SA) and American National Standards Institute (ANSI).

Brushless DC motors is a kind of permanent magnate synchronous motor. Permanent magnet synchronous motors are classified on the basis of the wave shape of their induce emf, i.e, sinusoidal and trapezoidal. The sinusoidal type is known as permanent magnet synchronous motor (PMSM); the trapezoidal type goes under the name of PM Brushless dc (BLDC) machine. Table (2.1) shows the difference between (PMSM) and (BLDC) motor.

Solar energy is a gateway that will ideally lead us far from our petroleum subordinate sources. The significant issue with sun based board innovation is that the efficiencies for sun based power frameworks

This report aims to discuss the working of DC-AC converter for photovoltaic systems and how it has been implemented to convert renewable energy into usable power to be supplied to the load (power supply application).A topology of a two-stage DC-AC converter has been designed in which a boost converter and a full bridge inverter act as an interface between the photovoltaic (PV) array and the power supply applications. A controlled strategy called Maximum Power Point Tracking (MPPT) technique has been used for achieving maximum power output at the load. Various modes of operation of the converter and the inverter are also discussed. MATLAB Simulink environment has been used for designing the circuitry and to observe various waveforms related to the output.

Recently, the technological advancements in power electronics and semiconductor technologies have led to improvements in power electronic systems. The purpose of this project is to design a Boost Converter which is a DC-to-DC power converter with an output voltage exceeding than its input voltage. Boost converter is applied in many applications that require higher DC voltages for superior performance as this helps in reducing the size of the systems because the battery powered systems generally stack cells to attain higher voltage leading to larger size of the system.

The disadvantage of Simple Boost Control(SBC) is overcome by introducing the Maximum Boost Control(MBC) method. In case of MBC the traditional zero state is totally converted into shoot-through state as a result the voltage stress across the switch is reduced compared to SBC.

Pulse width modulation technique based cascaded multilevel inverters have been receiving increasing research attention in the past few years. These power converters provide advantages of high power quality waveforms, low switching losses, and high-voltage capability. It has led to many applications such as high-power motor drive, variable speed drive, Uninterruptible Power Supply and active power line conditioners. The various topological structures of the multilevel inverter suggestions

In this paper a zero voltage switched active network (Fig. 1) used in combination with three-phase ac to dc diode rectifiers is presented. It is shown that by using proposed switching network in three-phase ac to dc boost converter, zero switching losses are obtained while maintaining a unity input power factor. Active network capacitor, Cs, diodes D7, and D8, maintain a zero voltage during turn-off of Q1, and Q2, Capacitor, Cs, discharges through the boost inductors of the circuit thus limiting the rate of rise of current during turn-on. Moreover, the advantage of the proposed active network is that it can maintain a zero voltage switching over the entire range of the duty cycle of the operation. Consequently, boost stage can be used directly to control the dc bus voltage by varying the duty cycle at Constant switching frequency. The resulting advantages include higher switching frequencies, and better efficiency. Finally the operation of the active switching network is verified experimentally on a prototype three-phase ac to dc converter.

In the present era of advanced technologies, power electronics devices have wide applications. These devices are important for industrial and domestic uses but they generate the power quality problems [1-2].these problems are created on account of these devices

L. Hsiu et al. [34] at low output ripple and noise in voltage and current and for this design a model of coupled inductor and transformers on a common core is use that provide Zero-voltage– switched Dual–SEPIC converter with coupled inductor. H. F. Bilgin et al. [35] gave a design criteria, operating feature and characteristic of the buck type PWM rectifier employed in a unity PF dc motor drive. As per this paper single–stage UPF buck –type PWM uses For-low harmonic distortion in Ac supply current and nearly UPF over a wide operating shaft speed Range. And these output voltage and current in limit avoid any type of failure risk in current connection even for oldest motor design, aging in insulation, mechanical failure due to circulation

Key words – i) Effect of series resistance ii) i-v characterstics iii) Power region iv) Power Plane Analysis v)Maximum Power Point Tracking.

So that the voltage and current is of poor qualities and the switching frequency causes more amount of switching losses. Those drawbacks are rectified using three phase neutral point clamped multilevel inverter. The voltage and current quality are better and the switching losses are reduced when compared to the conventional technique. Also the THD is found to be better.