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Harald Enzinger, Christian Vogel Telecommunications Research Center - - PowerPoint PPT Presentation

Analytical Description of Multilevel Carrier-Based PWM of Arbitrary Bounded Input Signals Harald Enzinger, Christian Vogel Telecommunications Research Center Vienna (FTW), Austria IEEE International Symposium on Circuits and Systems 2014


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SLIDE 1

Analytical Description of Multilevel Carrier-Based PWM of Arbitrary Bounded Input Signals

Harald Enzinger, Christian Vogel

Telecommunications Research Center Vienna (FTW), Austria

IEEE International Symposium on Circuits and Systems 2014 Melbourne, Australia

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SLIDE 2

Pulse Width Modulation (PWM)

Introduction

  • Efficient signal generation
  • Power electronics
  • Audio
  • Communications

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SLIDE 3

Carrier-based PWM

Introduction

  • Simple implementation
  • Basis for most PWM modulators

2/15

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SLIDE 4

Multilevel carrier-based PWM

Introduction

  • Less distortion
  • Lower switching voltage

3/15

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SLIDE 5

Analytical description of carrier-based PWM

  • Arbitrary input signal
  • Arbitrary number of levels
  • Arbitrary carrier configurations

Relevance

  • Spectral analysis
  • Comparison of existing modulation schemes
  • Insight for research on new modulation schemes

Problem Statement

4/15

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SLIDE 6

Black, 1953

  • Double Fourier series

Song, 2003

  • Combination of pulse spectra

Hausmair, 2013

  • Partial Fourier series

State of the Art

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 Many carrier configurations  Extension to multilevel  Single tone input signal  Arbitrary input signals  Many carrier configurations  Not well suited for multilevel  Arbitrary input signals  Extension to multilevel  Specific carrier configuration

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SLIDE 7

Generalization of Hausmair 2013

  • Arbitrary input signals
  • Arbitrary number of levels
  • Arbitrary carrier configurations

Application examples

  • Amplitude slicing PWM
  • Phase interleaving PWM

Spectral analysis

  • New analytical/numerical approach

Contributions

6/15

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SLIDE 8

System Model

(a) Multilevel PWM model (b) Binary PWM element (c) Piecewise-linear carrier Parameters:

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SLIDE 9

System representation by 2-dimensional function

Analysis of System Model

Implicit mathematical description Periodicity in time-dimension

Fourier series expansion in time-dimension is possible.

8/15

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SLIDE 10

Fourier series

Analytical Description

Fourier coefficients Parameters

Duty cycle Pulse center

9/15

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SLIDE 11

Multilevel PWM Schemes

10/15

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SLIDE 12

Amplitude slicing

Multilevel PWM Schemes

10/15

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SLIDE 13

Amplitude slicing

Multilevel PWM Schemes

10/15

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SLIDE 14

Amplitude slicing

Multilevel PWM Schemes

10/15

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SLIDE 15

Amplitude slicing

Multilevel PWM Schemes

10/15

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SLIDE 16

Amplitude slicing

Multilevel PWM Schemes

Phase interleaving

10/15

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SLIDE 17

Amplitude slicing

Multilevel PWM Schemes

Phase interleaving

10/15

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SLIDE 18

Amplitude slicing

Multilevel PWM Schemes

Phase interleaving

10/15

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SLIDE 19

Amplitude slicing

Multilevel PWM Schemes

Phase interleaving

10/15

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SLIDE 20

Amplitude slicing

Multilevel PWM Schemes

Phase interleaving

Parameters: Parameters:

10/15

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SLIDE 21

Fourier series

Unified Description for M-Level

Harmonic amplitude distortion

Amplitude Slicing and Phase Interleaving

11/15

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SLIDE 22

Conventional numerical approach

  • Time-domain simulation
  • FFT analysis of PWM signal

 Very high oversampling  No insight into cause of distortion

Proposed analytical/numerical approach

  • Analytical description
  • FFT analysis for each harmonic

Only moderate oversampling Insight into the cause of distortion

Spectral Analysis

12/15

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SLIDE 23

Multitone input signal

Spectral Analysis

Oversampling of simulation: Number of averages for PSD: Oversampling of PWM:

13/15

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SLIDE 24

Spectral Analysis

Comparison of number of levels

Amplitude distortion:

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SLIDE 25

Analytical description of carrier-based PWM

  • Arbitrary input signals
  • Arbitrary number of levels
  • Arbitrary carrier configurations

Examples

  • Amplitude slicing
  • Phase interleaving

Spectral analysis

  • Less computation
  • More insight

Summary

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