Online Health Monitoring of DC-Link Capacitors in Modular Multilevel Converters for FACTS and HVDC Applications

• This article presents an online health monitoring scheme for dc capacitors in modular multilevel converters (MMCs). The health monitoring algorithm is based on detecting changes in the dc capacitance value over time. The proposed algorithm only utilizes measurements that are typically available in flexible alternating current transmission systems and high-voltage direct current applications. Hence, in the proposed estimation method, no additional sensors are used. The estimation scheme considers the presence of noise in voltage and current measurements, and utilizes a recursive least square estimator in conjunction with a special low-pass filter to minimize the estimation errors. Simulation results of a hardware replica, as well as experimental results on a low-power MMC prototype show that the proposed scheme can identify the dc-link capacitance value with a maximum error of 1%.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik -- Annan elektroteknik och elektronik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering -- Other Electrical Engineering, Electronic Engineering, Information Engineering (hsv//eng)

Nyckelord

Capacitors

Estimation

Capacitance

Current measurement

Voltage measurement

Automatic voltage control

Monitoring

DC capacitor

flexible alternating current transmission systems (FACTS)

health estimation

modular multilevel converter (MMC)

online monitoring

reliability

Publikations- och innehållstyp

ref (ämneskategori)

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