Terminal characteristics measurements and analysis of the three‐phase Active Front‐End converter building block

Marko Petković,Dražen Dujić

doi:10.1049/elp2.12107

Abstract

The safe and reliable operation of a modern power system imposes the need to describe and estimate the system stability through impedance-admittance measurement and identification. The integration and operation of medium voltage equipment in existing infrastructure requires impedance-admittance measurement devices which are currently few in number and often limited in output voltage level and output bandwidth. The four-quadrant Cascaded H-Bridge (CHB) topology, featuring a three-phase Active Front-End (AFE) and a single-phase H-Bridge inverter presents itself as a potential solution to this problem. To support the development of the CHB topology the AFE hardware and control platforms require implementation and testing. The testing aspect of the process additionally includes the measurement of terminal characteristics such as the input admittance and the output impedance. The complexity of the CHB converter and its increased number of power electronics building blocks requires the use of industrial control platforms. This work defines the hardware implementation and control principle of the three-phase AFE of a CHB converter as well as the system for measuring its terminal characteristics. The results obtained show that the proposed system can be successfully used to measure the input admittance and output impedance of the AFE upon which the development of the CHB is based.

Highlights

The energy demand growth in combination with the advancement in design and performance of power electronics converters has resulted in putting into service renewable energy systems as well as, extensive installation of power conversion equipment
The implemented experimental setup for the ac-side input admittance measurement using the elements outlined is presented in Fig. 12 while for the setup for the measurement of the dc-side output impedance one can refer itself to the right hand side of Fig. 7
Even though injecting more voltage is desirable from the standpoint of obtaining better measurements, it is in turn undesirable from the perspective of the system protection, the level of injected voltage must be carefully chosen in order not to perturb the normal operation of the Active Front End (AFE)

Summary

Introduction

The energy demand growth in combination with the advancement in design and performance of power electronics converters has resulted in putting into service renewable energy systems as well as, extensive installation of power conversion equipment. Medium voltage impedance/admittance measurement devices that exist today have been presented in [6,7,8,9]. These solutions have either limited bandwidth, up to 1 kHz or comprise an output side transformer in order to step-up the voltage to the MV levels. The demand for the MV measurement equipment is growing due to the need to support the development of recent MVdc and already established medium voltage ac (MVac) applications, grid integration of renewable energy sources and storage devices, energy transmission and distribution in the MV range and ensure safe integration with the existing apparatus. Recent research focusing on the identification of impedance footprint of renewable energy sources such as wind farms has been presented in [13, 14], showing that there is a need for the measurement devices that could serve the needs of these systems

Methods

Results

Conclusion