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Existing control strategies of modular multilevel converter (MMC) have many drawbacks, such as need of several parameter controllers, complex parameter tuning and huge computational burden. This paper proposes a novel control method based on the hybrid architecture of proportional integral (PI) control and model predictive control (MPC). The PI controller is used as external controllers to control...
This paper presents a new control strategy for Modular Multilevel Matrix converters where the output frequency is higher then the input frequency. In operating points when ωout ≥ ωin the energy pulsation in the converter cells are dominated by the second harmonic of the input frequency. These energy pulsations can be identified and compensated by inducing additional currents. The results are verified...
This paper provides a novel voltage space vector modulation algorithm dedicated to the inverter fault-tolerant motor drive systems based on the four-switch inverter topology. The proposed technique ensures an accurate phase voltage modulation even under a DC-link voltage imbalance. Moreover, the capacitor voltages of the DC-link are leveled up so that the simultaneous motor drive operation is obtained...
The increasing number of renewable energy sources and their integration into the medium voltage grid leads to an increasing interest in multilevel structures for the interfacing power electronic converters. A feasible topology for MV applications is the Stacked Multicell Converter (SMC) offering a modular structure and several voltage levels. A robust control, current limiting strategies under grid...
Modular Multilevel Converter (MMC) technology is rapidly evolving, and research is ongoing to make the MMC suitable for more applications. This topology comprises multiple Sub-Modules (SM) to form the output voltage levels with lower order harmonic contributions. In this paper, a reconfiguration control method for continuous operation during bypassed faulty SM is presented. The method accomplish to...
Realization of high power conversion system utilizing parallel connected power converters rated at much smaller power levels due to limitations in switching device voltage and current ratings would be highly desirable. Therefore, modular configured converters are imminent in high power industrial applications due to their numerous benefits over singular high capacity converter or inverter. They can...
This paper proposes a new strategy for balancing the Capacitor Voltages (CVs) for Modular Multilevel Converters (MMCs). The balancing is one of the main challenges in MMC applications and it is usually solved by adopting a global arm control approach. For performing such an approach, a sorted list of the SubModules (SMs) according to their capacitor voltages is required. A common way to accomplish...
The CLIC study is exploring the scheme for an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. The CLIC pre-damping rings and damping rings will produce, through synchrotron radiation, ultra-low emittance beam with high bunch charge, necessary for the luminosity performance of the collider. To limit the beam emittance blow-up due to oscillations, the pulse...
A multi-port converter configuration which achieves a high-power DC-AC conversion for a large-scale grid-connected photovoltaic system is utilized. A novel multi-port nonlinear control is proposed to realize a voltage and current control strategy among cascaded ports. Each port consists of solar panels, a multilevel dual-active bridge DC-DC converter utilizing a secondary step-up high-frequency transformer,...
The modular multilevel-based power converters (MMC) are very interesting solutions for high power transmission over large distances. The modularity of the converter is achieved by cascading individual and low voltage rated power converters in series, until the stack built can withstand the required dc voltage. Due to the large number of those individual components in real VSC-HVdc applications, the...
In this paper a new voltage measurement technique for modular multilevel converter (MMC) capacitors is proposed. While all the capacitors voltages should be known for closed loop control of MMCs, only the arms voltages are measured employing the proposed method. Therefore, the number of voltage sensors reduced dramatically to one per arm. The capacitors voltage quantities are updated continuously...
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,...
Excessive power loss is a major concern in high voltage and high power applications and is considered one of the main drawbacks of VSC-HVDC system when compared with traditional HVDC system based on thyristor technology. This is primarily caused by high switching loss associated with switching devices used in the VSC-HVDC. This issue can be largely addressed by using the emerging MMC-HVDC topology,...
Single-phase photovoltaic (PV) energy conversion systems are the main solution for small-scale rooftop PV applications. Some multilevel topologies have been commercialized for PV systems and an they are attractive alternative to implement small-scale rooftop PV applications. Efficiency, reliability, power quality and power losses are important concepts to consider in PV converters. For this reason...
This paper work exploits a new dual open-winding three-phase multilevel inverter configuration suitable for high power medium-voltage applications. Modular structure comprised of standard three-phase voltage source inverter (VSI) along with one additional bi-directional semiconductor device (MOSFET/IGBT) per phase and two capacitors with neutral point. Hence, introduces the additional voltage levels...
CEA is working on a solid state pulse modulator to drive an electron gun, source of an RF accelerator. The application requires square pulses in the range of 140kV (1% flat top), 10A, 150μs width, at a repetition rate of 50Hz and a reproducibility pulse-to-pulse better than 10−3. This modulator is based on a Marx topology which employs standard 1700V IGBTs and diodes to control the charge, discharge...
The large number of voltage levels and high quality of a modular multilevel converter (MMC) output voltage and current makes modulation at fundamental frequency a viable alternative. However, a staircase output voltage does not necessarily translate to fundamental switching frequency of the MMC submodules (SMs). This is because the voltage balancing algorithm usually requires several SMs to switch...
A solid-state modulator rated for 50 kV, 120A, 4μs and 250 Hz has been designed. The discharging circuit of the modulator is being tested at ∼ 33 kV, 40–80A, at a maximum pulse repetition rate of 30 pps. The paper discusses development and testing of prototype discharging circuit on resistive load and magnetron. The technique used for measurement of pulse transformer leakage inductance, distributed...
This paper deals with an enhanced modulator concept for the Modular Multilevel Converter. Based on an overview on existing concepts including module sorting algorithms and measurement results from a hardware-setup in laboratory, a new concept is developed. Measurement results of the implemented new algorithm for module selection and capacitor energy balancing in various operating points of the converter...
The development of static power converters capable of transforming DC energy obtained from alternative sources into AC has become one of the main challenges in renewable energy systems. In this context, the buck-boost inverter is advantageous for being capable of providing an AC output voltage higher or lower than the input DC voltage in a single power conversion stage. In this paper, a controller...
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