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Boost converters are widely used in several applications such as solar PV systems, energy storage systems, etc. In order to improve its dynamic performance, several model predictive control (MPC) strategies have been proposed to govern this DC-DC converter. However, in general, they require long prediction horizons to achieve a stable closed-loop due to its well-known non-minimum phase behavior. A...
Smart grid is a developing field for energy researchers. It offers technological improvements to have more controllable, reliable and sustainable power grids. Especially, the decreasing trend of fuels has pressurized to pay researchers’ attention to renewable energy sources such as solar systems and wind turbines. The renewable energy sources generate electric power in different characteristics. Therefore,...
Conventionally, only one out of the two capacitors in a three-level submodule is involved in the arm current path to generate the first non-zero voltage level (E) in modular multilevel converters (MMCs). While two capacitors are connected in series to obtain the second non-zero voltage level (2E). In this paper and in order to generate the first non-zero voltage level (E); parallel-connection of the...
We present a control approach for the modular multilevel converter (MMC) with series and parallel module connectivity (MMSPC) that provides natural module balancing, reduced conduction losses, and enhanced robustness afforded by the parallel mode. In conventional MMC control, the voltage of each module's storage element has to be measured or estimated to enable the controller to equalize the voltages...
Recently, a hybrid modular multilevel converter with cascaded full bridges (HMMC-CFB) is proposed. This converter has mainly two parts: a director part (DP) and a wave shaping part (WSP). The DP consists of a conventional modular multilevel converter (MMC) with half bridge submodules (HBS). The WSP is a series connection of full bridge submodules (FBS) and attenuates the voltage harmonics produced...
This paper presents a digital Active Gate Drive (AGD) methodology for power semiconductor devices. The inherent latency limitation of digital signal processing systems is addressed by a sequential optimization procedure that uses voltage and current signals recorded at the previous switching edge to develop an optimized gate drive waveform for the next switching edge. Experimental results using a...
The modular multilevel converter (MMC) is a highly efficient multilevel converter topology suitable for high and medium voltage applications. However, one of the negative traits of MMC is the existence of circulating current. The detrimental effects of circulating currents include distortion in arm voltages, converter power loss and high switching stresses on semiconductor devices. This paper aims...
In this paper, a new approach to the discontinuous modulation technique for the operation of the modular multilevel converter (MMC) is presented. Discontinuous modulation is based on adding a zero-sequence to the original modulation signals so that each MMC arm is clamped to the upper or lower terminals of the dc-link bus during some intervals. In combination with a circulating current control, the...
The Modular Multilevel Converter (MMC) is a relatively new converter topology which has been favoured for high voltage DC transmission due to its performance, flexibility in control and its modular and scalable design which allow it to be used over a wide variety of system voltage levels and power ratings. The converter consists of a number of cascaded half bridge cells with isolated capacitors to...
The modular multilevel converter (MMC) is one of the most promising converter topologies for medium/high-power applications. One of the technical challenges associated with the control of an MMC is the capacitor voltage balancing among arm capacitors. This paper presents a novel capacitor voltage balancing method combined with the carrier-phase-shifted pulse-width modulation (CPS-PWM) for MMC without...
This paper describes a control approach that allows the cell capacitor voltages of the full-bridge modular multilevel converter (FB-MMC) to be controlled independent of the input dc link voltage. Moreover, this control approach offers the possibility of operating FB-MMC from bi-polar dc link voltages; thus, creating new possibilities for building generic hybrid dc grids with reversible dc link voltage,...
This paper describes a control approach that allows the cell capacitors of the full-bridge modular multilevel converter (FB-MMC) to be controlled independent of dc link voltage. Also the control approach offers the possibility of operating the FB-MMC from bi-polar dc link voltages; thus, creating new possibilities for building generic hybrid dc grids with reversible dc link voltage, where conventional...
Modular multilevel converters (MMC) are used in the applications such as medium voltage multi-megawatt drives and in HVDC power transmission. The converter has several sub-modules connected in series that are switched appropriately to regulate the pole voltage. Besides regulation of output voltage, it is also essential to regulate the individual sub-module capacitor voltages. In this paper, a novel...
Alternate Arm Converter (AAC) is considered as a new breed of hybrid multilevel voltage source converters. In this paper, modeling, design and control of the Alternate Arm Converter (AAC) are presented and operation principles of the AAC is discussed. One of the issues regarding to the AAC is the switching between the upper and lower arms which provides hard switching of the so called Director Switches...
This paper analyzes the station-internal phase-to-ground fault in bipolar HVDC transmission systems. An overvoltage problem due to the existence of the bipolar cells in the modular multilevel converter (MMC) arms closer to the grounding pole are presented. Consequently, a new hybrid arm MMC is proposed to overcome the overvoltage problem while providing the benefits of: a lower number of cells, fewer...
In this paper, a power module capacitor voltage balancing method is presented for a ±350 kV/ 1000 MW modular multilevel converter (MMC) oriented for a back-to-back grid interconnecting project. In this method, a Balancing Adjusting Number (BAN) is proposed to adjust the voltage balancing effect and the switching frequency of the power modules. An accurate switching frequency calculation method is...
This paper focuses on the determination of suitable carrier based pulse width modulation (PWM) switching and control methods for grid connected modular multilevel converters (MMCs). Characterization of various level-shifted and phase-shifted carrier based PWM methods are provided in terms of output voltage waveforms both for N+1 and 2N+1 level output phase voltages. Carrier based PWM method based...
In this paper an active power filter is presented based on a multilevel converter. The active power filter is intended to be used in domestic applications where reactive power compensation in two-phase networks is required. An innovative technique to balance the DC bus voltages of the power converter capacitors is proposed and also an estimation algorithm for those voltages is developed, allowing...
The paper presents a newly introduced Voltage Source Converter (VSC) topology called as an Alternate Arm Modular Multilevel Converter (AAMMC). The different high voltage and industrial applications mainly based on the multilevel converters which are discussed briefly. The main purpose of this paper is to study the basic converter structure, its operating principle and its control strategy. The main...
In this paper, a new cell based Modular Multilevel Converter (MMC) for AC-AC and AC-DC applications is presented. The new topology makes use of an efficient Packed U-Cells (PUC) structure to form the Multi-Cells Modular Multilevel Converters (M3C). It is a member of MMC root family, with extended operational capability covering therefore AC-AC and AC-DC modes of operation. A dynamic model of the PUC...
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