Solid-state transformer stability and control considerations

This paper addresses the stability issues and some control solutions in solid-state transformers (SST). An SST is built using three cascaded stages, including an ac-dc rectifier, a dual active bridge (DAB) converter, and a dc-ac inverter. Multistage cascaded converters are highly prone to instabilities due to the interaction between stages. Hence, the control system must be designed in a way that solves this detrimental interaction effect. Additionally, the stability issue can become even more complicated when a distributed energy storage device (DESD) and a distributed renewable energy resource (DRER) are added to the SST. In this paper, the stability of the SST is studied by applying the Middlebrook's criterion. To do so, the converters' small-signal models will be derived, and the frequency domain analyses is carried out to predict the time domain behavior of the SST. An average model of SST will be simulated in PSCAD to validate the stability analyses predictions.

[1]  Wen Xuhui,et al.  Dynamics and Control of Electronic Cascaded Systems , 2006, 2006 CES/IEEE 5th International Power Electronics and Motion Control Conference.

[2]  D. Boroyevich,et al.  Small-signal modeling and control of three-phase PWM converters , 1994, Proceedings of 1994 IEEE Industry Applications Society Annual Meeting.

[3]  Robert W. Erickson,et al.  Fundamentals of Power Electronics , 2001 .

[4]  Keith Corzine,et al.  A hybrid multilevel inverter with both staircase and PWM switching schemes , 2010, 2010 IEEE Energy Conversion Congress and Exposition.

[5]  R. Ayyanar,et al.  Stability analysis of cascaded converters for bidirectional power flow applications , 2008, INTELEC 2008 - 2008 IEEE 30th International Telecommunications Energy Conference.

[6]  S.K. Panda,et al.  A Simple Single-Input–Single-Output (SISO) Model for a Three-Phase PWM Rectifier , 2009, IEEE Transactions on Power Electronics.

[7]  Keith Corzine,et al.  A generalized capacitor voltage balancing scheme for flying capacitor multilevel converters , 2010, 2010 Twenty-Fifth Annual IEEE Applied Power Electronics Conference and Exposition (APEC).

[8]  Hao Yuan,et al.  Research on voltage and power balance control for cascaded modular solid-state transformer , 2011, IEEE Transactions on Power Electronics.

[9]  S. Bhattacharya,et al.  A three-phase three winding topology for Dual Active Bridge and its D-Q mode control , 2012, 2012 Twenty-Seventh Annual IEEE Applied Power Electronics Conference and Exposition (APEC).

[10]  M. Veerachary,et al.  Stability Analysis of Cascaded DC-DC Power Electronic System , 2007, 2007 7th International Conference on Power Electronics and Drive Systems.