Modular multilevel converter with thyristor DC-link switch for full-torque variable-speed drives

Zhou, Shaoze, Li, Binbin, Xu, Dianguo and Li, Gen ORCID: https://orcid.org/0000-0002-0649-9493 2023. Modular multilevel converter with thyristor DC-link switch for full-torque variable-speed drives. CSEE Journal of Power and Energy Systems 9 (1) , pp. 293-305. 10.17775/CSEEJPES.2021.00500

Preview

PDF - Accepted Post-Print Version Available under License Creative Commons Attribution Non-commercial No Derivatives. Download (12MB) | Preview

Abstract

The modular multilevel converter (MMC) is a promising topology for medium-voltage drive applications due to its high-quality output waveforms, low device switching frequency and voltage rating. However, the large cell capacitor voltage ripple is a severe challenge faced by MMC at low motor speeds. Recently, a hybrid MMC (HMMC) topology is proven to be a competitive solution because of its lower cell capacitor voltage ripple and no common-mode voltage (CMV) problem compared with other methods. However, the dc-link switch with IGBT limits HMMC to be applied for high-voltage applications. This paper uses the thyristor instead of IGBT as the dc-link switch. To ensure the thyristor can be softly turned on and safely turned off, a new control scheme is proposed. When using this proposed scheme, HMMC can also tolerate the failure of thyristor's turning-off without shutting down the system, improving the reliability effectively. The cell capacitor voltage ripple analysis is presented considering the effects of the thyristor switching process. In addition, a decoupled energy balancing control is utilized to suppress the fluctuation of dc current. Experimental results obtained from a 380 V/7.5 kW downscaled prototype validate the effectiveness of starting up a motor from the standby mode to rated speed with full-torque.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Engineering
Publisher:	IEEE
ISSN:	2096-0042
Date of First Compliant Deposit:	10 June 2021
Date of Acceptance:	10 June 2021
Last Modified:	29 Nov 2024 20:00
URI:	https://orca.cardiff.ac.uk/id/eprint/141847

Actions (repository staff only)

Edit Item