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Neutral point modulation in three-level inverter to reduce the size, cost and loss of passive filter structure

IP.com Disclosure Number: IPCOM000235516D
Publication Date: 2014-Mar-05
Document File: 23 page(s) / 1M

Publishing Venue

The IP.com Prior Art Database

Abstract

This invention disclosure presents a method to reduce the value of the inductance in the passive filter in three-level inverter applications. The method consists of introducing an additional modulation circuit that controls the voltage of the neutral point in order to reduce the applied voltage on the filter inductor. Based on the simulation analysis, this method allows significant reduction in the inductance, resulting in savings in power loss, cost and physical size of the passive filter.

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Page 01 of 23

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Date: March 5, 2014 Page: 1/23 Neutral point modulation in three-level inverter to reduce the size, cost and loss of passive filter structure

Abstract

This invention disclosure presents a method to reduce the value of the inductance in the passive filter in three-level inverter applications. The method consists of introducing an additional modulation circuit that controls the voltage of the neutral point in order to reduce the applied voltage on the filter inductor. Based on the simulation analysis, this method allows significant reduction in the inductance, resulting in savings in power loss, cost and physical size of the passive filter. CONTENT

1 Field of the invention.............................................................................. 3


2 Introduction ............................................................................................ 2


3 Description of the invention .................................................................. 3


3.1 Statement of the problem ..................................................................................................3

4 State-of-the-art solutions ....................................................................... 7


5 Invention principle................................................................................ 10


5.1 Operating principle ..........................................................................................................10


5.2 Proof of Concept .............................................................................................................12


5.3 Applications.....................................................................................................................23


5.4 Business benefits............................................................................................................23


5.5 Key invention principles...................................................................................................23

6 Conclusions.......................................................................................... 23


7 References............................................................................................ 24 © Copyright 2014 ABB Technology Ltd, Affolternstrasse 44, CH-8050 Zurich, Switzerland. All rights reserved.


Page 02 of 23

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Date: March 5, 2014 Page: 2/23 1 Field of the invention

   The present invention is in the field of power electronics converter / inverter circuit topology. The invention is aimed to renewable energy applications, especially to photovoltaic power systems.

2 Introduction

   A conventional photovoltaic (PV) power system comprises photovoltaic modules arranged into strings and an inverter, that delivers the generated power into a single- or three-phase AC grid. Due to switching action, a passive filter structure is required to remove high-frequency content of the current that is injected into the grid. This passive filter is typically realized with...