AC characteristics in AC/DC/DC conversion (original) (raw)

A New Configuration of Symmetrical PWM AC Chopper For Three-Phase Systems

Recently, a new generation of ac-ac converters with more commutations per half cycle has been proposed for ac power conditioning due to the increasing availability and power capability of controlled-on and controlled-off power switching devices. This paper presents a simple topology of symmetrical PWM ac line conditioning approach for three phase systems. The topology uses a minimal number of controlled switches and feature buck voltage capability. The converter is seen to be an ac voltage regulator with output voltage range of 0-1 p.u. with reasonable current and voltage waveforms. The paper contains analytical expressions and simulation results.

Simulation and Experimental Analysis of an AC-DC Converter with D.C Load

In this research paper total harmonic distortion of three phase supply system (half and full wave) AC/DC converter-fed with DC motor load is analyzed ,using both simulation and experimental arrangements, it is keenly important to analyze harmonic contents, because of harmonics injection has very bad effects in electrical power system and the overall efficiency of the system becomes low, which results poor power quality, current and voltage distortion and at input AC mains power factor becomes also low. [4] In this research work we have proposed three phase full wave AC-DC converter topology which is better for energy conversion as compared to three phase half wave AC-DC converter topology ,using MATLAB /simulation as well as from the experimentaly performed setup, it was found that DC motor efficiency for three phase full wave rectified-fed is better as compared to three phase half wave rectified-fed.

Fork-Connected Autotransformer Based 30-Pulse AC-DC Converter for Power Quality Improvement

International Journal on Electrical Engineering and Informatics, 2012

This paper presents the design and analysis of a novel T-connected autotransformer based 30-phase ac-dc converter which supplies direct torque controlled induction motor drives (DTCIMD's) in order to have better power quality conditions at the point of common coupling. The proposed converter output voltage is accomplished via three paralleled 10-pulse ac-dc converters each of them consisting of 5-phase diode bridge rectifier. A T-connected autotransformer is designed to supply the rectifiers. This autotransformer makes use of only two single-phase transformers, resulting in reduced volume, weight, and the cost of the drive as compared with polygon structure. The design procedure of magnetics is in a way such that makes it suitable for retrofit applications where a six-pulse diode bridge rectifier is being utilized. The proposed converter requires only three inter-phase transformers in the dc link that yields in the reduced kilovolt ampere rating, size, weight, and cost of the proposed rectifier. The aforementioned structure improves power quality criteria at ac mains and makes them consistent with the IEEE-519 standard requirements for varying loads. Furthermore, near unity power factor is obtained for a wide range of DTCIMD operation. A comparison is made between 6-pulse and proposed converters from view point of power quality indices. Results show that input current total harmonic distortion (THD) is less than 3% for the proposed topology at variable loads.

New AC-AC converter topologies

2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692), 2003

This paper presents new AC-AC converter topologies operating as AC voltage regulators. Operation stages, static gain expressions, main waveforms and simulation results are shown. Laboratory experimental results for 1 kVA converters are also presented, which demonstrate the feasibility of the study carried out. Index Terms-AC-AC converter, voltage regulator, new topologies. . The power switches are ideal; 427 0-7803-7912-8/03/$17.00 0 2003 IEEE

Improvement of Power Quality Using PWM Rectifiers

The paper presents the modeling, simulation and analysis of an AC-DC converter based PWM rectifier. It provides a suitable control algorithm for a pulse width modulation rectifier which reduces ripple from the DC output side as well as shapes the input current properly. The basic objective of a PWM rectifier is to regulate the DC output voltage and also ensure a sinusoidal input current and unity power factor operation. This is implemented by high speed IGBT switches connected in anti parallel mode across the rectifier diodes. The output voltage is controlled by switching these IGBTS and higher order ripples at the output can be easily eliminated with the help of passive filters. Lower order harmonics are eliminated using PWM technique. The control subsystem generates gating pulse to the universal bridge by passing the output voltage through a network consisting of comparator, discrete PI controller and discrete PWM generator. The output of this generator are the gating pulses to be applied to the universal bridge.

Review of three-phase PWM AC–AC converter topologies

Industrial Electronics, IEEE Transactions on, 2011

This paper presents first an overview of the wellknown voltage and current dc-link converter topologies used to implement a three-phase PWM ac-ac converter system. Starting from the voltage source inverter and the current source rectifier, the basics of space vector modulation are summarized. Based on that, the topology of the indirect matrix converter (IMC) and its modulation are gradually developed from a voltage dc-link backto-back converter by omitting the dc-link capacitor. In the next step, the topology of the conventional (direct) matrix converter (CMC) is introduced, and the relationship between the IMC and the CMCs is discussed in a figurative manner by investigating the switching states. Subsequently, three-phase ac-ac buck-type chopper circuits are considered as a special case of matrix converters (MCs), and a summary of extended MC topologies is provided, including three-level and hybrid MCs. Therewith, a common knowledge basis of the individual converter topologies is established.

Comparative Study of Pulse Width Modulated and Phase Controlled Rectifiers

International Journal of Engineering Research and, 2015

Fixed DC voltage is one of the very basic requirements of the electronics' circuits in modern systems. Thus, single phase diode or thyristor rectifiers are commonly used in many industrial applications where we require a highpower DC supply or an intermediate DC link of AC/AC converters. The benefits include simple structure, high safety and most importantly, low cost. However, it is reasonable to assume that a price is to be paid for these benefits. The major drawback is the power system harmonics that these bridge rectifiers introduce within a system. The economic advantage that these systems enjoy can be nullified overnight if stricter harmonic standards are implemented. With this in mind, there is an increased interest in active filters and schemes like PWM that can counter these. The less prominent (but important from the consumers' point of view) issues include low power factor, voltage distortion, heating of transformer cores etc. A single standard scheme that can work for all applications is an ideal yet impractical solution. Thus, different schemes that have been introduced need to be compared so that it is easier to choose whichever fits best with the task at hand.

A new AC/AC power converter

2017 IEEE Southern Power Electronics Conference (SPEC), 2017

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