Mingwan Mei¹, Ping Wang¹, Yanbo Che^1,*, Zihan Lv¹, Zmarrak Wali Khanand¹, Chao Xing^1,2

Energy Engineering, Vol.119, No.2, pp. 591-607, 2022, DOI:10.32604/ee.2022.016585

Abstract

In the medium voltage direct current (MVDC) transmission system, a small number of MMC sub modules will reduce the power quality. In this paper, based on the research background of Photovoltaic Medium Voltage Direct Current (PV-MVDC) system, a Hybrid Modulation Strategy based on the Decoupled Double Synchronous Reference Frame (DDSRF) control strategy is proposed. The dual arm complementary hybrid modulation combining nearest-level-SPWM (NL-SPWM) can keep the number of SMs in the ON state constant. Then, the corresponding voltage sharing control algorithm of sub module (SM) is introduced. Through theoretical calculation, the modulation strategy can be found to stabilize the DC… More >

Liao Tian-fa

Intelligent Automation & Soft Computing, Vol.25, No.4, pp. 695-704, 2019, DOI:10.31209/2019.100000073

Abstract With the spreading of Photovoltaic (PV) grid-connected system, grid-connected reactive-load compensation and harmonic control is becoming a research focus. Unipolar and bipolar modulations are widely used in active power filter of PV grid-connected inverter. Unipolar modulation is good at harmonic, ripples and efficiency control, while bipolar modulation is good at grid-connected current control. A comprehensive comparison between the aforementioned modulation strategies in aspects of basic switching action, effects on operation mode, current harmonics，efficiency, is done in this paper. Base on it, a hybrid modulation strategy with the fusion of the unipolar and bipolar modulation is proposed in this paper. Numerical… More >

C. Gopinath^{1, *}, M. Rajvikram¹

CMES-Computer Modeling in Engineering & Sciences, Vol.115, No.3, pp. 359-386, 2018, DOI: 10.3970/cmes.2018.06143

Abstract This research paper proposes a single phase fifteen level inverter for a grid connected PV system. The proposed inverter is also called cascaded asymmetric multilevel inverter. By adopting appropriate hybrid modulation technique improved output voltage is obtained with minimum number of power electronic switches. By reducing the number of gate triggering circuits of the switches, the size and power consumption of the driving circuits can be reduced. The total harmonic distortion of the output of the inverter is improved by this inverter. The proposed inverter developed by cascading a full bridge inverter with modified H bridge multilevel inverter. The validity… More >