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In this publication, we discuss the recent upgrade of the intermediate power amplifier (IPA) of the 520 MeV Cyclotron's RF system. The main goal of this upgrade was to separate first and second stages of the IPA, and thus achieve a modular configuration. A novel neutralization circuit for the second stage was designed, simulated, fabricated and tested with maximal CW power of up to 65 kW. We discuss...
SiC JFET bi-directional switches (BDS) are widely used in construction of matrix converters, multi-level converters, solid state switches, etc. In this research work, the phenomenon of unwanted turn-on (UTO) of SiC JFET-based BDS and its related constant envelop oscillation is investigated. This phenomenon is critical to power conversion systems' stability and reliability. Firstly, the roots of UTO...
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...
Compared with the conventional high voltage DC power supply, the high voltage pulse power supply can significantly improve the dust removal efficiency of electrostatic precipitator and reduce the energy consumption. This paper presents a new type of high voltage pulse electrostatic precipitator power supply topology, the symmetric cascaded structure of the low voltage side which can significantly...
In this paper, a novel LLC resonant converter with parallel input and parallel output circuit topology is proposed to achieve the good performance of reduced switch count and medium power compared with conventional parallel half-bridge resonant converter. The proposed LLC resonant converter has two resonant circuits, two resonant circuits use the same power switches to transmit power so that the switch...
Wireless charger for Electric Vehicles (EVs) is an off-line application and it needs power factor correction (PFC) function, which usually consists of a front-end boost PFC and a cascaded DC/DC converter. Z-source resonant converter (ZSRC), a single-stage solution with low cost and high efficiency, was proposed for EV wireless charger lately. The Z-source capacitors in the ZSRC are designed to absorb...
In order to support different types of rechargeable batteries (e.g. Li-Ion, Lead-Acid, NiMh), the design of universal battery chargers must focus on wide output voltage regulation, rather than on constant voltage regulation. The universal battery charger is expected to provide a demanding output voltage range between nominal and 1.5 times nominal, while sustaining the maximum power delivery and maintaining...
This paper presents a simple passive voltage balancing circuit for a modular DC/DC step-up converter for medium voltage (MV) DC grid in wind energy systems. The proposed auxiliary circuit is able to balance the capacitor voltages over a wide range of operating points. Regarding the converter, high frequency step-up resonant circuits with high gain rectifier modules are combined to form a modular step-up...
The specific problems of the disconnection of HVDC breakers need an analysis of performances at laboratory scale. In the study of hybrid circuit breakers with commutation, three steps are necessary: modeling, simulation and experimental tests. The paper presents a modeling procedure for a hybrid commutation breaker intended to operate using resonant circuits phenomenon. Using the Matlab platform,...
This paper deals with the transformation from differential to common mode noise due to slightly unbalanced filter capacitors in a three-phase motor drive system. Indeed, filter components, i.e., inductors and capacitors, can be slightly different due to the tolerance of commercial products usually varying from 5% to 20%. Such components discrepancies result in noise transformation from differential...
Research on direct current (dc) interruption has grown in recent years, driven by increased interest in using high voltage direct current (HVDC) for large power transmission and future grids. In fact, dc interruption poses particular challenges to protection devices and circuit breakers and new technologies are needed to meet the requirements of future HVDC grids. In this paper we review some of the...
This paper proposes a methodology of design and control, and shows the main simulation and experimental results for a LLCC Series-parallel resonant converter applied to Wireless Power Transmission (WPT) in-motion. Using Induced Power Transfer (IPT) and considering a near-field energy-transfer method (less than 20 cm), the converter is applied in a small scale electric vehicle (EV). The modeling was...
This paper proposes full-wave voltage doubling type series-synchronized switch harvesting on inductor (S-SSHI) circuit for piezoelectric energy harvesting. A conventional circuit is composed of a full-bridge rectifier circuit and SSHI circuit to increase the output power. In the proposed circuit, a full-wave voltage doubling rectifier is chosen and the SSHI circuit is included in the rectifier circuit...
DC neutral breakers are used to reconfigure HVDC transmission systems. One example is the Metallic Return Transfer Breaker (MRTB) that commutates the current from the ground to an overhead line or cable reducing time duration with current flowing in the ground path. An MRTB consists of a passive LC-circuit in parallel with an AC breaker that triggers a resonance by its arc voltage characteristics,...
In brief, some properties of non-Foster circuits (NFC) are linked to the negative group delay (NGD) network. These properties are negative group delay and phase. It means that the NGD in conjunction with the effect of negative impedance is used to improve bandwidth of radio frequency (RF) modules. In this paper, we propose a design of passive non-Foster circuit by using NGD network that designed by...
This paper proposes a new soft-switched High Step-up DC-DC converter for energy storage systems in DC traction vehicles. In this converter, soft-switching operation, i.e., zero current switching has been obtained by employing dual resonant auxiliary circuits to the conventional step-up DC-DC converter. The auxiliary resonant consists of additional auxiliary switches; inductor and capacitor are used...
DC circuit breakers are needed in future HVDC grids to provide selectivity in clearing DC faults and to achieve continuous operation of the healthy part of the grid. Standard mechanical circuit breakers as used in AC systems cannot be used in HVDC applications due to the lack of current zero-crossing, which is essential for arc extinction. To use mechanical interrupters for fault current interruption...
The paper presents a technique of parameter stabilization of a wireless, resonance based energy transfer system for maximizing its power. The technique combines tuning of resonant frequency by means of variable capacitance and adjustment of magnetic coupling to maximize power. The paper presents experimental test results on a laboratory prototype of the system.
The multilevel converters have advantages of low voltage stresses of the switches and possible reduction of size of the passive components. Input-series output-series (ISOS) configuration of the converter enable the utilization of low voltage rating switches in converters with high input voltage and high output voltage in applications that requires galvanic isolation. While multilevel topology offers...
The series resonant DC/DC converter with an isolation transformer and bridge mode inverter input junction, at its operation in the Buck case, is investigated, at that input DC supply circuit comprises the qZ (quasi-Z) link as impedance source. Operation at such Buck case can be provided under different inverter bridge control methods. Recommended by the literature sources, is the method of control...
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