Stability assessment of high-bandwidth DC voltage controllers in single-phase active-front-ends: LTI vs LTP models

Salis, Valerio; Costabeber, Alessando; Cox, Stephen M.; Formentini, Andrea; Zanchetta, Pericle

Abstract

In recent years, a considerable effort has been made to minimise the size of DC-link capacitors in single-phase activefront-ends (SP-AFE), to reduce cost and to increase power density. As a result of the lower energy storage, a high-bandwidth outer DC voltage control loop is required to respond to fast load changes. Linearised modelling is usually performed according to the power-balance method and the control is designed using LTI techniques. This is done assuming negligible voltage ripple at twice the grid frequency, and the model is considered valid up to the grid frequency. However, its precise validity limits are usually unknown and the control design becomes empirical when approaching these boundaries. To overcome this drawback, Linear Time Periodic (LTP) theory can be exploited, defining the range of validity of the LTI model and providing precise stability boundaries for the DC-link voltage loop. The main result is that LTP models more accurately describe the system behaviour and provide superior results compared to the LTI ones. Theoretical analysis, simulations and extensive experimental tests on a 10 kW converter are presented to validate the claims.

Citation

Salis, V., Costabeber, A., Cox, S. M., Formentini, A., & Zanchetta, P. (2018). Stability assessment of high-bandwidth DC voltage controllers in single-phase active-front-ends: LTI vs LTP models. IEEE Journal of Emerging and Selected Topics in Power Electronics, 6(4), 2147-2158. https://doi.org/10.1109/JESTPE.2018.2810282

• Journal Article Type: Article
• Acceptance Date: Feb 12, 2018
• Online Publication Date: Feb 28, 2018
• Publication Date: Dec 1, 2018
• Deposit Date: Feb 26, 2018
• Publicly Available Date: Feb 28, 2018
• Journal: IEEE Journal of Emerging and Selected Topics in Power Electronics
• Electronic ISSN: 2168-6785
• Publisher: Institute of Electrical and Electronics Engineers
• Peer Reviewed: Peer Reviewed
• Volume: 6
• Issue: 4
• Pages: 2147-2158
• DOI: https://doi.org/10.1109/JESTPE.2018.2810282
• Keywords: Linear Time Periodic Systems, Harmonic StateSpace Model, Stability Analysis, Power Converters, Active-Front-Ends
• Public URL: https://nottingham-repository.worktribe.com/output/917470
• Publisher URL: http://ieeexplore.ieee.org/document/8304538/
• Additional Information: © 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works