The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The paper presents a new four-level voltage source converter (VSC). Compared to conventional four-level converters, this proposed converter has fewer components and can be used for a higher power density system in low and medium voltage applications. Its principles and advantages are studied in this paper. The effect of various redundant switching states on the voltages of flying capacitors is analyzed...
This paper proposes a transformer-less modular multilevel DC/DC converter. The proposed converter can be used to interconnect two HVDC systems with different dc voltage levels and realize bidirectional power flow. Based on the arm energy balance condition, the optimal design arming at minimum inner circulating current is presented. A power close-loop control method is adopted to regulate the converter...
Vector control is the most commonly used control strategy for modular multilevel converter (MMC) based HVDC system. However, due to the complicated structure of MMC, there is no precise mathematical model for the outer DC voltage loop. The conventional model ignores the capacitor voltage dynamics, and the AC voltage boosted operation scenario is not considered. This paper proposes a small signal model...
Modular multilevel converter (MMC) is a promising topology of Voltage Source Converter based High voltage Direct Current (VSC-HVDC) system with many outstanding advantages such as low switching frequency, low voltage distortion and harmonics. Pre-charge process is one of the core issues of MMC based system, especially for the MMC with DC fault blocking capability. In this paper, considering a novel...
The multilevel converter is a prospective topology for both Medium Voltage and High Voltage Direct Current (HVDC) applications. In high power application, the forward topology is applied to increase the power region. In this paper, a novel forward-mode five-level inverter is presented which combines the features of the conventional multilevel converters and forward topology. The converters can transfer...
A 4.6–5.6 GHz constant KVCO LC-VCO applied in PLL frequency synthesizer is presented in this paper. With constant KVCO LC-VCO and programmable charge pump, the frequency synthesizer is able to obtain constant bandwidth. Furthermore, the VCO has a low KVCO which will result low phase noise. An Optimized automatic frequency calibrator (AFC) is proposed, the AFC can select the sub-band which is nearest...
With the continuous development of high frequency inverter technology and multilevel inverter technology, all kinds of novel high frequency multilevel inverter are put forward and studied. And among them, the interleaved flyback three-level inverter (IFTLI) has a better work performance. In this paper, the control methods of single-phase IFTLI will be studied in-depth. Firstly, the instantaneous voltage...
Wireless power transfer has been introduced as a proper replacement for conventional cable power transfer systems recently. With the developments of the electric transportation, transferring power wirelessly has been found to introduce several advantages in charging Lithium-Ion batteries. Among different configurations of wireless power transfer, Series Parallel structure is found to be more interesting...
Cascaded multilevel inverter (MLI) topologies have received an attractive solution for grid connected PV system. In this paper, two-cascaded MLI topologies are presented for grid connected PV system. These are seven level cascaded H-bridge multilevel inverter and three phase cascaded voltage source multilevel inverter. In both presented MLI configurations, each PV module is connected to one DC-DC...
This paper discusses the active and reactive power control method for a modular multilevel converter (MMC) based grid-connected PV system. The voltage vector space analysis is performed by using average value models for the feasibility analysis of reactive power compensation (RPC). The proposed double-loop control strategy enables the PV system to handle unidirectional active power flow and bidirectional...
The paper proposes a three phase nine level T-type neutral point clamped (9L-T-NPC) inverter for medium voltage induction motor drive. The primary objective of the proposed inverter is to improve the output voltage quality with reduced number of devices and passive components. The generation of nine levels in the output pole voltage is achieved using only ten switches per phase. Although the similar...
Performance analysis and output voltage regulation of a cascaded step-up switched-capacitor converter (SCC) under zero voltage switching (ZVS) condition is analyzed in this paper. The ZVS condition (converter operation above its resonant frequency) provides 1) zero-voltage switching, which leads to a relatively higher efficiency compared to zero current switching (ZCS) under the resonant frequency...
Multiport Converter gets growing applications due to its advantages of flexible control mode, high power density, bidirectional power delivery capability etc. In this paper, a DAB based partial isolated DC-AC multiport power converter, which combines photovoltaic panel, battery storage and grid connection is studied. Modulation method, analysis for power transmission and control design are provided...
DC capacitor voltage imbalance is an inherent problem limited the further development of multi-level Neutral Point Clamped (NPC). In this paper, a new hybrid control method based on Space Vector Pulse Width Modulation (SVPWM) for five-level NPC at high modulation index and high power factor is presented. By choosing appropriate switching pattern in lower modulation index sectors and collocating different...
As the fluctuation of sub-module capacitance voltage when MMC operates at low frequency, the application of MMC in the field of motor drive has been limited. Therefore, this paper proposes a low frequency control method for the MMC with tuned filter circuit. Based on the theoretical analysis for this tuned filter, the circulating current of 2nd frequency could be suppressed effectively at rated frequency...
Voltage deviations of dc-link capacitors are the main problem of multilevel diode-clamped converters (DCC). In this paper, a novel carrier-based voltage balance method is proposed to balance the dc-link capacitors of five-level DCCs. The proposed method is characterized by injecting proper zero-sequence voltages in the modulation signals of carrier-based modulators. The effects of the injected zero-sequence...
Real-time simulation of modular multilevel converter (MMC)-based HVDC is one of the most important and difficult technologies in the area of power electronics research. This paper presents a methodology for the hardware in loop (HIL) CPU/FPGA-based real-time simulation of a one-terminal MMC HVDC of up to 468 levels using a detailed equivalent model, and the simulation system is based on full-scale...
The modular multilevel converter (MMC) has become the most attractive converter topology for medium/high-power applications. However, uneven power loss distribution and thermal loading among the semiconductor devices of each submodule (SM) compromise the reliability and lifetime of the converter. In this paper, an active thermal loading control method for the MMC is proposed to simultaneously (i)...
The negative- and zero-sequence currents of a modular multilevel converter (MMC) under imbalanced ac-grid conditions increase the maximum voltage of the submodule (SM) capacitors, which should be kept below a maximum voltage limit. This paper investigates the impact of offset pulse-width modulation (OPWM) on the capacitor voltage of the MMC under imbalanced ac-grid conditions. It is demonstrated that...
This paper presents a simplified direct modulation prediction approach for modular multilevel converters (MMC). By using the Euler approximation, the grid-side and circulating currents are firstly predicted to obtain the values in the next switching cycle. Then the modulations are directly calculated based on the established mathematical models for the six-arms of MMC. Subsequently, the capacitor...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.