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This paper presents a novel control method that enables operation of Modular Multilevel Converters under non-sinusoidal AC supply conditions based on frequency domain decomposition of supply voltages. The proposed control method enables to inject or draw near sinusoidal grid currents even during the presence of harmonic distortions in the supply voltages without the use of additional hardware filters...
Presently the choice of circuit parameters in the design of Modular Multilevel Converters (MMC) depends on iterative time-consuming simulation runs. This paper presents a method based on the Floquet-Lyapunov Theorem by which the dynamic characteristics are predicted analytically. Graphs of damping factors plotted against circuit parameters are showed by which designers will select to improve the damping...
This paper presents a design methodology with uncertainty quantification to estimate the required margin for two main design variables in a modular multilevel converter (MMC). In this methodology, the minimum required design margins are calculated by quantifying all sources of uncertainty in the modeling and simulation of MMCs. To this end, an enhanced modeling framework is presented to take into...
Modular multilevel converters (MMC) are emerging to be an alternative approach for realizing power converters for a variety of high power applications because they allow series-cascaded levels and/or parallel-connected branches. However, the design of communication interface between system controller and individual modules became increasingly complicated as more modules been added into the system,...
The modular multilevel converter (MMC), is widely adopted in high voltage applications because of its simplicity and modularity. However, the current and power flow is very complicated. As a result, methods proposed for capacitor reduction, which is required to stored line frequency related circulating energy, all went through complicated mathematical derivation. C. Li proposed a state plane analysis...
This paper proposes two hybrid asymmetric cascaded multilevel inverters. Both inverters consist of the series connection of a three-level (3L) H-bridge cell and a nine-level (9L) H-bridge cell with an unequal dc voltage ratio of 1:8. The topologies of the 9L H-bridge cell are based on modular multilevel cascade converter (MMCC) with double-star chopper cells (DSCC). Both the proposed inverters can...
This paper aims to investigate through simulations and experimental results the effects of frequency on the iron losses in laminations adopted for electrical machines. To this aim, a comparison between an iron loss separation model and an advanced model (based on a nonlinear homogenization technique and the Jiles-Atherton model) is presented. Then, a new measurement method is introduced: an industrial...
This paper proposes a novel bi-directional battery charger structure for V2G applications. The proposed structure consists of a flexible AC/DC converter and a series resonant converter (SRC). The flexible AC/DC converter changes the DC bus voltage according to the power flow direction of the charger. In this way, SRC which basically only works in buck mode is able to operate in both directions, and...
In the hybrid energy management systems of plug in electric vehicles (PEVs), a power electronic interface (PEI) is required to interface among the grid side dc link, the onboard battery pack, and the ultra-capacitor (UC) bank. In this paper, an integrated three-port PEI is proposed for use in such applications. The PEI integrates the interleaved bidirectional buck/boost topology with the bidirectional...
Gallium nitride (GaN) devices, as their better performance in high temperature, high efficiency and high power density converters, have been recognized as the most promising successor for Si MOSFET in the future. In order to take advantages of the superiority of depletion-mode GaN devices, a low voltage Si MOSFET is in series to drive the depletion-mode GaN device, which is well known as cascode structure...
The synchronous inductances of permanent magnet machines are usually measured by means of off-line measurements based on single-phase connection schemes of the three-phase windings. Through experiments and comparative analyses with respect to the three-phase symmetrical supply case, it has been observed that the results obtained for the inductance measurement is dependent on both the winding connection...
An investigation into magnetic gear modulating ring design shapes and the performance of a magnetic gear integrated into an induction machine are presented. Modulating ring construction is one of the more difficult aspects of magnetic gear design, and a compromise between magnetic performance, losses in conductive supporting parts and manufacturability is often required. Six possible designs for modulating...
This paper proposes an adaptive democratic current sharing control scheme for interleaved dc-dc converters under faulty condition. The proposed fault tolerant control approach can achieve the desired output voltage generation, and equal current sharing among the remaining healthy modules as more and more modules fail. The main idea is to adaptively change the outer voltage and inner current controller...
To improve the reliability of modular multilevel converter (MMC), the fault submodules must be isolated rapidly. In this paper, a new fast fault diagnosis method is proposed containing two steps: fault detecting and fault locating. Fault detection step finds failures by improved predictive model which detects the fault by comparing the difference between the predictive value and the measured one of...
Induction motors, which have been widely used in various practical applications, such as fans, pumps, machine tools, vehicle traction motors, etc., are truly the industrial workhorses over the past 120 years. To improve the sensorless induction motor control performance and develop more fault-tolerant motor drives, the paper presents a novel sensorless direct torque control approach based on the proposed...
The advancements in wide-band-gap (WBG) devices are enabling applications of power electronics converters coupled directly to medium voltage and incorporating galvanic insulation within the converter using high-frequency solid-state transformers. This paper presents the design and the characterization results of a SiC H-bridge converter suitable for up to 100 kVA single-phase ac-dc modular solid-state...
This paper describes the effect of MOSFET internal capacitances on the channel current during the turn-on switching transition: an intrinsic theoretical switching speed limit is found and detailed mathematically. The set of analytical equations is solved and the effect of the displacement currents is highlighted with ideal simulated waveforms. A laboratory experiment is thus performed, in order to...
This paper presents a detection method of small-foreign-metal particles using a 400 kHz silicon-carbide (SiC)-metal-oxide-semiconductor field-effect-transistors (MOSFETs) high-frequency inverter. A 400 kHz SiC-MOSFETs high-frequency inverter is developed and applied to small-foreign-metal particles detection on high-performance chemical films (HPCFs). A new placement of induction heating (IH) coils,...
Wide Band Gap power semiconductor switching devices offer superior performance compared to an equivalent Si power device. SiC MOSFETs can be competitive when compared to Si IGBTs of the same voltage class, whilst offering greater benefits at high switching frequencies. Operating SiC MOSFETs at high switching frequencies imposes significant challenges, including: Ringing and voltage overshoot issues,...
Brushless doubly-fed induction generator (BDFIG) is a new type of ac induction machine and can be used for both grid-connected and stand-alone power generation. The conventional control methods for the BDFIG almost all rely on the encoder, which brings many limitations in terms of cost, complexity, reliability, and so on. This paper presents a new rotor speed observer (RSO) for the encoderless operation...
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