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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,...
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...
Modular cascaded multilevel converter is a promising option for high power solar photovoltaic (PV) system due to its modularity, scalability, and distributed maximum power point tracking (MPPT) capability, etc. Nevertheless, inherent mismatch and varied operating conditions (both called module-mismatch) are still the issues to be disclosed. Asymmetrical active power harvesting among individual PV...
Silicon super-junction MOSFETs have very low on-state resistances and fast switching characteristics. However, their use in voltage-source converters is hindered by the poor reverse recovery performance of their body drain diode and an adverse output capacitance characteristic. These both act to increase the overall switching loss. The on-state resistance and output capacitance characteristics of...
Reducing the power loss of a converter without increasing volume or cost in hardware has always been a much sought-after, but challenging goal. This paper discusses a scheme to improve the system overall efficiency while still meeting a given THD requirement by implementing variable instantaneous switching frequency method without any hardware changes. This paper aims at minimizing the combined switching...
An experimental 30 kW boost composite converter is described in this paper. The composite converter architecture, which consists of a buck module, a boost module, and a dual active bridge module that operates as a DC transformer (DCX), leads to substantial reductions in losses at partial power points, and to significant improvements in weighted efficiency in applications that require wide variations...
As SiC MOSFET is moving towards high current rating through parallel devices in a module, the ability to switch it fast with minimum switching loss becomes a new challenge. Amid this new challenge, power converter designers need to deal with more demanding measurement method to obtain correct switching waveforms. Switching waveforms are an important asset for converter designers because they can reveal...
A comparison of the two-level voltage-source inverter, the three-level Neutral-Point-Clamped inverter and the T-Type inverter based on the power semiconductor rating is presented for drive inverters of electric vehicles. The comparison of the power semiconductor design rating is done for four different drive train configurations: normal operation with a constant DC-link voltage, an overload capability,...
Improvements in 900V SiC MOSFET technology have resulted in switches that have extremely low ON resistance in high-speed packages. 900V SiC MOSFETs are promising candidates for hard switched and soft-switched power supply applications due to low ON resistance at higher temperature, a robust low-recovery body diode, avalanche capability and low output stored charge. System designers will be able to...
In this paper a novel structure of a zero- voltage transition PWM boost converter is proposed. The main switch and diode of the converter are turned on and off under zero voltage transition. In addition the auxiliary switch and both diodes operate in ZCT condition. The auxiliary circuit consists of a transformer, a snubber capacitor and two diodes. Without imposing much current stress, the switching...
This paper presents an experimental efficiency comparison study between two different AC-AC converter prototypes: the direct matrix converter (DMC) and indirect matrix converter (IMC). The evaluation is performed under different load conditions and using discrete IGBTs at a power level up to 9k[W]. The losses measurement is carried out by means of two power analyzers: one placed at the input and one...
This paper presents two discontinuous pulse width modulation (DPWM) methods for three phase Vienna rectifiers with different performance optimization targets. One for switching loss minimization and one for switching loss reduction with the neutral point voltage controllability. Due to the current commutation characteristics if Vienna rectifiers, the available space voltage vectors are limited. With...
In this paper, a simple and accurate analytical loss model for Silicon Carbide (SiC) power devices is proposed. A novel feature of this loss model is that it considers the package and PCB parasitic elements in the circuits, nonlinearity of device junction capacitance and ringing loss. The proposed model identifies the switching waveform subintervals, and develops the analytical equations in each switching...
An adaptive carrier based sinusoidal pulse width modulation (SPWM) technique for cascaded h-bridge (CHB) multilevel converters is presented in this paper. The proposed technique enables the CHB topology to provide a symmetrical ac voltage from a set of time-variant input dc source voltages. Two alternative approaches, namely the single-carrier and dual-carrier algorithms, are described for implementing...
PWM strategy is classified into a Continuous PWM (CPWM) and a Discontinuous PWM (DPWM). Because the conventional DPWM has constant non-switching period which is 120° of fundamental period, DPWM could bring about the high Total Harmonic Distortion (THD) compared to CPWM and the lower switching loss than CPWM. This paper presents a carrier-based Adjustable Discontinuous Pulse Width Modulation (ADPWM)...
This paper proposes a switching method and a LC design method in order to suppress the distortion of the input current which occurs in a high efficiency AC-AC converter. The proposed AC-AC converter which is used in online-type Uninterruptible Power Supplies (UPS) is constructed by a T-type three-level rectifier and a T-type three-level inverter. The switching loss of the proposed AC-AC converter...
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