Novel isolated cascaded half-bridge converter for battery energy storage systems

This paper presents a novel isolated cascaded half-bridge converter for medium voltage battery energy storage systems with three phase legs of series connected modules in star connection. Each module consists of a grid-side half-bridge, a battery-side full-bridge and a medium-frequency transformer providing isolation. The presented modulation ensures grid-side zero-current-switching (ZCS) and battery-side zero-voltage-switching (ZVS). The control system consists of a grid current control as well as a state-of-charge (SOC) balancing control for the batteries. Evaluation of the proposed module of a 6.6 kV, 150 kW, 1MWh design example shows an average module efficiency of 97.4% including semi-conductor and transformer losses. Simulation results verify the converter concept including the applied control structures.

[1]  Felix Jauch,et al.  Generalized modeling and optimization of a bidirectional dual active bridge DC-DC converter including frequency variation , 2014, 2014 International Power Electronics Conference (IPEC-Hiroshima 2014 - ECCE ASIA).

[2]  J. Biela,et al.  Single-phase single-stage bidirectional isolated ZVS AC-DC converter with PFC , 2012, 2012 15th International Power Electronics and Motion Control Conference (EPE/PEMC).

[3]  C.O. Nwankpa,et al.  A new type of STATCOM based on cascading voltage source inverters with phase-shifted unipolar SPWM , 1998, Conference Record of 1998 IEEE Industry Applications Conference. Thirty-Third IAS Annual Meeting (Cat. No.98CH36242).

[4]  H. Akagi,et al.  A Transformerless Energy Storage System Based on a Cascade Multilevel PWM Converter With Star Configuration , 2008, IEEE Transactions on Industry Applications.

[5]  Hirofumi Akagi,et al.  A battery energy storage system based on a multilevel cascade PWM converter , 2009, 2009 Brazilian Power Electronics Conference.

[6]  Alex Q. Huang,et al.  Voltage and Power Balance Control for a Cascaded H-Bridge Converter-Based Solid-State Transformer , 2013, IEEE Transactions on Power Electronics.

[7]  J. Muhlethaler,et al.  Modeling and multi-objective optimization of inductive power components , 2012 .

[8]  Charles R. Sullivan,et al.  Accurate prediction of ferrite core loss with nonsinusoidal waveforms using only Steinmetz parameters , 2002, 2002 IEEE Workshop on Computers in Power Electronics, 2002. Proceedings..

[9]  H. Akagi,et al.  Active-Power Control of Individual Converter Cells for a Battery Energy Storage System Based on a Multilevel Cascade PWM Converter , 2012, IEEE Transactions on Power Electronics.

[10]  Johan Driesen,et al.  Switching control strategy to extend the ZVS operating range of a Dual Active Bridge AC/DC converter , 2011, 2011 IEEE Energy Conversion Congress and Exposition.

[11]  P. L. Dowell,et al.  Effects of eddy currents in transformer windings , 1966 .

[12]  M. Vasiladiotis,et al.  Modular converter architecture for medium voltage ultra fast EV charging stations: Global system considerations , 2012, 2012 IEEE International Electric Vehicle Conference.

[13]  A. Oudalov,et al.  Optimizing a Battery Energy Storage System for Primary Frequency Control , 2007, IEEE Transactions on Power Systems.

[14]  Leon M. Tolbert,et al.  Multilevel converters for large electric drives , 1998, APEC '98 Thirteenth Annual Applied Power Electronics Conference and Exposition.

[15]  Stig Munk-Nielsen,et al.  A new modular multilevel converter with integrated energy storage , 2011, IECON 2011 - 37th Annual Conference of the IEEE Industrial Electronics Society.

[16]  Rainer Marquardt,et al.  An innovative modular multilevel converter topology suitable for a wide power range , 2003, 2003 IEEE Bologna Power Tech Conference Proceedings,.

[17]  V.G. Agelidis,et al.  Offset rejection for PLL based synchronization in grid-connected converters , 2008, 2008 Twenty-Third Annual IEEE Applied Power Electronics Conference and Exposition.

[18]  M. Aredes,et al.  Discrete-time implementation of second order generalized integrators for grid converters , 2008, 2008 34th Annual Conference of IEEE Industrial Electronics.