G. Kishor Babu and B. Madhu Kiran, Improving the Voltage Level in High Voltage Direct Current Systems by Using Modular Multilevel Converter. journal = {International Journal of Electronics and Communication Engineering}, [online]. World Academy of Science, Engineering and Technology. June 2019, vol. 151(7). 492 - 506 [viewed 26 April 2024]. Available from: https://publications.waset.org/pdf/10010591.