Category: Pulse width modulation pdf nptel

Toggle navigation. Civil Engineering Computer Sc. Electrical Engineering. Management Mathematics Mechanical Engineering. Home Electrical Eng. Pulse width Modulation for Power Electronic Converters.

Narayanan from IISc Bangalore. Click on any Lecture link to view that video. Electronic switches 2.

VF drives V: Single phase PWM inverter (unipolar), 2/11/2014

DC - DC converters 3. DC - AC converters 4.

Unipolar and Bipolar PWM Inverter

Multilevel converters - I 5. Multilevel converters - II 6. Applications of voltage source converter - I 7. Applications of voltage source converter - II 8.

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Applications of voltage source converter - III 9. Purpose of PWM-I Low switching frequency PWM - I Selective harmonic elimination Off-line optimized pulsewidth modulation Sine-triangle pulsewidth modulation Harmonic injection pulsewidth modulation Bus-clamping pulsewidth modulation Triangle-comparison based PWM for three-phase inverter Concept of space vector Conventional space vector PWM Space vector based bus-clamping PWM Space vector based advanced bus-clamping PWM Contents: Overview of power electronic converters : Electronic switches - DC - DC converters - DC - AC voltage source inverter - Voltage source and current source inverters - Multilevel inverter - diode clamped inverter - Multilevel inverter - flying capacitor inverter.

Applications of voltage source converter : Applications of voltage source converter I motor drives, active rectifiers - Applications of voltage source converter II reactive current and harmonic compensation. Analysis of line current ripple : Transformation from stationary reference frame to synchronously revolving dq reference frame - Volt-second balance and instantaneous error voltage - Calculation of RMS line current ripple - Space vector-based hybrid PWM for reduced line current ripple.

Analysis of dc link current : Inverter state and dc link current - Average and RMS values of dc link current. Inverter loss : Evaluation of conduction loss - Dependence of switching loss on power factor and modulation method - PWM techniques for reduced switching loss.

Effect of inverter dead-time : Effect of dead-time with continuous modulation - Effect of dead-time with discontinuous or bus-clamping PWM. Overmodulation : Per-phase approach to overmodulation - Space vector approach to overmodulation - A perspective from the synchronously revolving d-q reference frame. PWM for multilevel inverters : Extension of sine-triangle modulation to three-level inverters - Extension of conventional space vector modulation to three-level inverters - Analysis of line current ripple and torque ripple.

Excellent course helped me understand topic that i couldn't while attendinfg my college. Added to favorite list Updated On 02 Feb, Overview Contents: Overview of power electronic converters : Electronic switches - DC - DC converters - DC - AC voltage source inverter - Voltage source and current source inverters - Multilevel inverter - diode clamped inverter - Multilevel inverter - flying capacitor inverter.

Related Courses. Ratings 0. Comments Sam Sep 12, Excellent course helped me understand topic that i couldn't while attendinfg my college. Dembe March 29, Great course. Thank you very much.

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pulse width modulation pdf nptel

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Pulse width Modulation for Power Electronic Converters Video Lectures

R and Arokkia Jerald Praveen. The contents of this project work, in full or in parts, have neither been taken from any other source nor have been submitted to any other Institute or University for award of any degree or diploma and the same is certified.

However, it would not have been possible without the kind support and help of many individuals and organizations. We would like to extend my sincere thanks to all of them. We are highly indebted to Dr. We would like to express our gratitude to our chancellor Dr. G Visvanathan, Dr. Project Description and Goals Technical Specification Design Approach and Details Design Approach Rectifier circuit Power supply circuit PWM Mode Communication and Control Single Pulse Width ModulationPulse width modulation PWMor pulse-duration modulation PDMis a method of reducing the average power delivered by an electrical signal, by effectively chopping it up into discrete parts.

The average value of voltage and current fed to the load is controlled by turning the switch between supply and load on and off at a fast rate.

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The longer the switch is on compared to the off periods, the higher the total power supplied to the load. Along with MPPT maximum power point trackingit is one of the primary methods of reducing the output of solar panels to that which can be utilized by a battery.

The PWM switching frequency has to be high enough not to affect the load, which is to say that the resultant waveform perceived by the load must be as smooth as possible. The rate or frequency at which the power supply must switch can vary greatly depending on load and application.

The main advantage of PWM is that power loss in the switching devices is very low. When a switch is off there is practically no current, and when it is on and power is being transferred to the load, there is almost no voltage drop across the switch. Power loss, being the product of voltage and current, is thus in both cases close to zero.

PWM has also been used in certain communication systems where its duty cycle has been used to convey information over a communications channel.

The term duty cycle describes the proportion of 'on' time to the regular interval or 'period' of time; a low duty cycle corresponds to low power, because the power is off for most of the time. Here is a pictorial that illustrates these three scenarios:. Some machines such as a sewing machine motor require partial or variable power. In the past, control such as in a sewing machine's foot pedal was implemented by use of a rheostat connected in series with the motor to adjust the amount of current flowing through the motor.

It was an inefficient scheme, as this also wasted power as heat in the resistor element of the rheostat, but tolerable because the total power was low. This mechanism also needed to be able to drive motors for fans, pumps and robotic servosand needed to be compact enough to interface with lamp dimmers. PWM emerged as a solution for this complex problem. Of note, for about a century, some variable-speed electric motors have had decent efficiency, but they were somewhat more complex than constant-speed motors, and sometimes required bulky external electrical apparatus, such as a bank of variable power resistors or rotating converters such as the Ward Leonard drive.

Pulse-width modulation uses a rectangular pulse wave whose pulse width is modulated resulting in the variation of the average value of the waveform. The above expression then becomes:. The simplest way to generate a PWM signal is the intersective method, which requires only a sawtooth or a triangle waveform easily generated using a simple oscillator and a comparator. When the value of the reference signal the red sine wave in figure 2 is more than the modulation waveform bluethe PWM signal magenta is in the high state, otherwise it is in the low state.

In the use of delta modulation for PWM control, the output signal is integrated, and the result is compared with limits, which correspond to a Reference signal offset by a constant. Every time the integral of the output signal reaches one of the limits, the PWM signal changes state. In delta-sigma modulation as a PWM control method, the output signal is subtracted from a reference signal to form an error signal.

This error is integrated, and when the integral of the error exceeds the limits, the output changes state. Figure 4. Space vector modulation is a PWM control algorithm for multi-phase AC generation, in which the reference signal is sampled regularly; after each sample, non-zero active switching vectors adjacent to the reference vector and one or more of the zero switching vectors are selected for the appropriate fraction of the sampling period in order to synthesize the reference signal as the average of the used vectors.

Direct torque control is a method used to control AC motors. It is closely related with the delta modulation see above.A matrix converter is defined as a converter with a single stage of conversion. It utilizes bidirectional controlled switch to achieve automatic conversion of power from AC to AC. It provides an alternative to PWM voltage rectifier double sided.

Matrix converters are characterized by sinusoidal waveforms that show the input and output switching frequencies. The bidirectional switches make it possible to have a controllable power factor input. In addition, the lack of DC links ensures it has a compact design.

pulse width modulation pdf nptel

The downside to matrix converters is that they lack bilateral switches that are fully controlled and able to operate at high frequencies. Its voltage ratio that is output to input voltage is limited. It contains four bi-directional switches with each switch having the ability to conduct in both forward blocking and reverse voltage.

It creates AC waveforms that drive AC motors at various speeds. In the case of a three-phase inverter having DC supply power, its three main legs at the output are connected to a 3-phase motor. The switches are under control to ensure that no two switches in the same leg are ON at the same time. Simultaneous ON states could result in the DC supply shorting. This leads to eight switching vectors where two are zero and six are active vectors for switching.

Power Electronics - Matrix Converters Advertisements. Previous Page. Next Page. Previous Page Print Page.To browse Academia. Skip to main content. Log In Sign Up.

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Long T Pham. Abstract— Three phase voltage source inverters supply calculated and it is determined if the system is in the over variable voltage and frequency to alternating current machines. Third, the reference voltage vector section Pulse width modulation PWM is often used to transfer supply is found, as are the adjacent space vectors based on sector angle. Space Tsource and phase angle. Finally, for different switching states, vector pulse width modulation SVPWM is a computationally controlled PWM technique applied in industry for its efficient use the modulation times are calculated [4].

Pulse-width modulation

SVPWM is applied to of direct current voltage, low switching loss, low computational output voltage and input current; the main objective being complexity, and high flexibility. We collected information from approximation of reference voltage vector utilizing eight available sources in order to understand SVPWM and the switching patterns [5].

The most common application of particular qualities this type of PWM presents. This mathematical reasoning, and modulation strategy sections clearly technique generates less harmonic distortion in output voltage present information to the reader. SVPWM high switching under unbalanced motor operation conditions leading it to be rates lead undesirable total harmonic distortion rates.

pulse width modulation pdf nptel

Research into methods of reducing this total harmonic distortion is the PWM technique of choice. This technique held strong advantages allowing for higher DC bus efficiency, voltage magnitude control, low power losses, and variable frequency control. Other advantages of SVPWM include a wide linear modulation range, low switching loss, easy implementation, and fewer computations due to the reduced number of sin functions. Doubly Fed Induction Generator configuration for WTS [9] PWM aims to control duty ratio of pulsating waveforms using an input waveform to calculate duty cycle of switches.

Waveform control is based on modulated signal information. There are many approaches to the modulation of signal information with none performing best for all situations. Each desired voltage vector can be simulated by an averaging effect between two adjacent active vectors and a zero vector.

Modulation strategy plays an important role in the minimization of harmonics and the switching losses in converters. The technique follows five set steps. First, phase angle and voltage reference vector is calculated based on input voltage components.

Second, the modulation index is Fig. Similarly, switching between V2 and V3 we can create Fig.

pulse width modulation pdf nptel

In speed Wind Turbine Systems. In both cases, the generator side this way we can output an average vector at any angle we want converter generates a 3-phase AC voltage from a DC supply to using just the six vectors in Fig. By controlling the magnitude and frequency of the output 3-phase AC voltage, the converter can control the torque of the generator to maximize energy harvesting from the wind. The 3-phase AC voltage can be constructed using various techniques.

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Two switches on the same leg cannot turn-on or turn- off at the same time, therefore, the state machine has eight states.Skip to search form Skip to main content You are currently offline. Some features of the site may not work correctly. Namboodiri and Harshal S. NamboodiriHarshal S. Wani Published Computer Science.

Inverter is basically an interface between DC source like photovoltaic cell and AC networks. There are many inverter topologies but output current distortion and efficiency are the two main parameters for the selection of inverters. Two such topologies are described herein.

Power Electronics - Pulse Width Modulation

Save to Library. Create Alert. Launch Research Feed. Share This Paper. Figures and Topics from this paper. Citations Publications citing this paper. Comparison and performance analysis of unipolar and bipolar digitally-controlled single-phase inverters Emad H. El-ZohriMohamed A. MakhubeleKingsley A.

Inverters for two phase induction motor P. GodboleA. Seyezhai References Publications referenced by this paper.

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