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In order to design and fabricate low profile (slim) LLC resonant converters, it is essential to replace conventional wire-wound magnetic transformers with low profile planar ones. In planar transformers, to decrease high-frequency AC resistance and to get high power efficiency, the primary and secondary PCBs are stacked together using the interleave structure method, which leads to a high amount of...
The paper proposes a current source based Dynamic VAR Compensator (DVC) control strategy. The switching unit in this DVC topology is composed of series connected switch and diode also termed as the “current switch”. The proposed controller has been designed to force discontinuous conduction mode operation thus fundamentally different from the traditional constant current source based control system...
This paper proposes a multilevel series compensator (MSC) to deal with: i) voltage sags/swells, ii) harmonic compensation or iii) reactive power compensation. Such a device can be considered as a dynamic voltage restorer (DVR) or a series active power filter (Series-APF). The MSC can improve the power-quality of loads located in stiff systems. The configuration is based on three-phase bridge (TPB)...
Datacenters are becoming a significant energy consumer and ideal candidates to operate as virtual power plant (VPP). In order to provide reliable power, datacenters are provided with on-site generators and large backup resources. These resources are designed to provide power during grid failure, therefore they are underutilized most of the time. In addition, load demand of the datacenter is flexible...
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,...
This paper investigates the power module design for better common-mode (CM) noise performance. A high frequency full-bridge diode rectifier is studied as an example. For this circuit, a comprehensive parametric study and a proposed CM equivalent model are first presented to identify the most influential factors in CM noise generation and mitigation. It is shown that proper parasitic value and parasitics...
This paper proposes three topologies of multilevel dynamic voltage restorer (DVR) with application in three-phase systems (balanced and unbalanced) to compensate sags/swells. The topologies use three independent dc-links (one per phase) and each converter is mounted with one three-level NPC leg (3L) and one two-level leg (2L), furnishing a five-level (5L) voltage at its output. This proposed topologies...
Power electronics converter systems (PECS) are significant corner stones in enormous variety of industrial applications, including smart grids and variable speed drives. One of the factors that assist to improve such systems is the study of their fault mode behaviors. Besides that, the open circuit (O-C) faults in the PECS do not trigger the standard protection systems in the converter but rather...
This paper describes a fast protection circuit for silicon carbide metal-oxide semiconductor field-effect transistors (SiC MOSFETs) subjected to hard-switching faults (HSFs). In terms of reliability of power converters, the protection of power semiconductors against short-circuit failures is of great concern. The reverse transfer capacitance increases with decreasing drain-source voltage during normal...
In this paper a unified Impedance-based Stability Criterion (UIBSC) has been proposed for paralleled grid-tied inverters. Compared to the traditional Impedance-based Stability Criterion (IBSC) which needs to evaluate all minor loop gains (MLGs) of each individual inverter, the UIBSC only checks the derived global minor loop gain (GMLG) once to determine system stability. As a result, the computation...
Detecting the load currents is a basic control method of paralleled active power filter (PAPF). The stability and compensation effect of the system would be influenced by the interactions of the load, weak grid and the paralleled active power filter (PAPF), when the load can't be equivalent to an ideal harmonic current source. The impedance models are established to analyze the stability of the system,...
A fuzzy reasoning based decision maker is developed in this study in order to determine the optimal capacitor location and sizing in radial distribution systems for the purpose of minimizing the power loss and capacitor cost with voltage limit constraints. The solution methodology includes two main parts. The first part is a fuzzy expert system that selects suitable candidate buses for capacitor locations...
Series LC-filtered active damper can be used to stabilize the grid-tied voltage source converter in a non-ideal grid. The operation principle of the active damper is to mimic a damping resistance at the resonance frequencies. However, the selection of the damping resistance has not received much attention. Also, parasitic capacitance of the grid transmission line brings new challenge for the application...
This paper defines a bandwidth over which power electronic HVAC (heating, ventilation, and air-conditioning) drives can operate such that when integrated with stochastic solar power they act as an effective electric swing bus to mitigate solar power variability. In doing so, grid power is shown to be substantially more constant, reducing the need for fast grid resources or dedicated energy storage...
This paper proposes a low cost gate driver of Silicon Carbide (SiC) MOSFET with a passive triggered auxiliary transistor in a phase-leg configuration. Silicon Carbide MOSFET can work on high blocking voltage and high switching frequency with less temperature drift. However, high switching speed may amplify the negative influence of parasitic components and produce significant voltage spikes during...
The switching transient properties of conventional power semiconductors (Silicon MOSFET and IGBT) have been proposed for online junction temperature (Tj) sensing. This method utilizes the semiconductor Tj dependent characteristics and the gate drive output dynamics. In this paper, the method is applied to wide bandgap power semiconductor, Silicon-Carbide (SiC) MOSFET. In order to demonstrate the SiC...
Gate drives of today's high-voltage insulated gate bipolar transistors (HV-IGBTs) are in most cases voltage source based and with fixed gate resistors. Consequently, the contradiction between high-speed switching for minimized power loss and low-speed switching for low noise and low switching stress cannot be resolved simultaneously. This paper proposes a novel active gate drive (AGD) which operates...
With the development of SiC technology, current rating of the latest SiC MOSFET module goes up to 300A and the gate charge becomes higher than 1000nC, which demands a high gating current to drive the power module. To explore the high current and high temperature (HT) potentials of the SiC MOSFET module, a gate driver circuit with high output current and HT capability is developed. In this paper, particular...
In this paper, we analyze the back electromotive force (BEMF) characteristics according to the magnetization pattern of irreversible demagnetization to determine the fault type for interior permanent-magnet (IPM) type brushless DC (BLDC) motors. We numerically model irreversible demagnetized PMs using space-harmonics analysis. In addition, we analyze the results using the finite element and analytical...
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