Mingda Jiang¹, Yanbo Che¹, Hongfeng Li^1,*, Muhammad Ishaq¹, Chao Xing^1,2

Energy Engineering, Vol.119, No.2, pp. 699-721, 2022, DOI:10.32604/ee.2022.017556

Abstract The full-bridge converters usually use transformer leakage inductance and parallel resonant capacitors to achieve smooth current commutation and soft switching functions, which can easily cause problems such as energy leakage and significant duty cycle loss. This paper designs a novel full-bridge zero-current (FB-ZCS) converter with series resonant capacitors and proposes a frequency and phase-shift synthesis modulation (FPSSM) control strategy based on this topology. Compared with the traditional parallel resonant capacitor circuit, the passive components used are significantly reduced, the structure is simple, and there is only a slight energy loss. By controlling the charging time of the capacitor, it can… More >

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 >