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Recently, the medium frequency power electronic traction transformer (PETT) has received increased attention in the rail transit applications due to its small size, light weight, more space availability for passengers, multiple interfaces and other additional functionalities. However, the switching frequency is limited by the thermal tolerance of semiconductors which deteriorate as the switching frequency...
A novel modulation technique for single phase grid-tied inverter is proposed in this paper. In normal discontinuous current mode (DCM) operation, the output current becomes distorted due to the resonant between parasitic output capacitors of switching devices and inductor during zero current periods if no current control method is applied. This low frequency distortion can be improved in the boundary...
This paper introduces a three-phase grid-connected inverter for commercial-scale photovoltaic systems. The circuit topology combines an electrolytic-capacitor-less and ac-inductor-less active bridge with a parallel-connected PWM inverter acting as an instantaneous reactive power compensator. The active bridge, called a 120°-conduction inverter, operates at the switching frequency equal to the grid...
Improving the power density of a power converter has many benefits for systems integration. Aspects such as thermal management, weight, conformation to mounting locations, and the footprint of the converter all become critical factors as systems continue to scale down in size. The flying-capacitor multilevel (FCML) converter topology is of interest because it has characteristics which contribute to...
Single stage power factor corrected (SSPFC) AC-DC converters are attractive in particular applications because they are less expensive than conventional two-stage converters. One of the main drawbacks of SSPFC converters, however, is that their intermediate DC bus voltage varies considerably when used in universal voltage range applications. A new method for reducing the DC bus voltage variation for...
A high-performance DC-DC converter is presented to improve the efficiency and modularity of the vehicular power system. The converter is capable of bidirectional power transfer between the isolated voltage sources. GaN semiconductor switches in the converter turn on and off softly by utilizing the energy stored in the leakage inductance of a transformer. A quasi-resonant operation is also explained...
Boost type converters are commonly used as pre-regulators in applications such as photovoltaics, battery storage, and power factor correction. Normally, non-isolated step-up conversion is done using traditional hard-switching boost topologies, but these suffer from low efficiency due to hard switching transitions. Soft-switching boost topologies present an opportunity to increase switching frequency...
Industrial applications, e.g. semiconductor manufacturing equipment, require power amplifiers providing high power with high precision and bandwidth. Due to limitations in system infrastructure, increasing voltage is favorable to increasing current to generate more output power. This research presents a 5-level Flying Capacitor Resonant Pole Inverter (FC RPI) configuration that delivers high output...
Resonant filters can be beneficial for significant reduction of the filter size in buck converters. Compared to the conventional low-pass filter, the resonant filters can be designed to provide high attenuation to the ripple components near the pulse width modulation (PWM) switching frequency resulting in much smaller filter components. In traditional resonant filter, the high attenuation at a specific...
The Class E dc-dc converter, operating with the switching frequency up to multi-megahertz, is usually regulated by the basic ON-OFF control. In this paper, it is found that in the basic ON-OFF control, the resonant inductor current of the Class E dc-dc converter will be increase with the rise of the input voltage, which will enhance the output capacity of the converter and also increase the ON-OFF...
A hybrid modulation approach is proposed in this work, which allows to modulate the switches of the five level neutral point clamped inverter (5LANPC) with different switching frequencies. Some of the switches are controlled with a low switching frequency using six-step modulation and Optimized Pulse Patterns (OPPs), whereas the rest are modulated with a high switching frequency using Carrier-Based...
Advent of Modular multilevel converters (MMC) made the voltage sourced high voltage direct current (HVDC) transmission systems a reality mainly due to its modular structure, scalability and reliability. For these converters, minimization of sub-module (SM) capacitor voltage spread without increasing the switching frequency is the biggest challenge as it directly affects the efficiency and cost. Moreover,...
High-speed permanent magnet motors (HSPMMs) have gained ever-increasing interests in high speed direct-drive applications due to their advantages of high-power density, small size and high efficiency. However, the low stator inductance of the HSPMM causes large current ripple in the stator current, therefore brings additional iron loss. The Modular multilevel converter (MMC) increases both voltage...
Common mode voltage (CMV) and switching frequency of an inverter fed induction motor drive are dependent quantities. Increase in common mode voltage (CMV) with increase in switching frequency for induction motor drive is studied in this paper. Conventional sinusoidal pulse width modulation technique is used to drive an inverter fed induction motor. It is demonstrated that the peak value of CMV increases...
This paper presents a complete design procedure for a motor drive aiming at maximizing nominal power within loss (30 W) and form factor (60 inch3) constraints. Particularly, this motor drive system has EMI requirement on both input and output sides and it should be free convection cooled. Loss-size Pareto fronts of multiple three-phase topologies including two-level voltage source converter (VSC),...
A high step-up-ratio DC/DC converter for photovoltaic energy integrated into high voltage DC grids is proposed in this paper. The converter is mainly composed of modular DC/DC conversion modules which are configured as input-parallel-output-series structure. The proposed module is consisted of two power stages, with a boost circuit as the first stage and a narrow-switching-frequency-variation LLC...
High frequency is an effective method to improve transmission efficiency of inductively coupled power transfer (ICPT) system. However, it is hard for the high capacity semiconductor device to meet the high frequency need. In this paper, a novel multiple-frequency inductively power transfer system is proposed. By adopting a novel multiple-frequency topology of inverter, the transfer frequency of the...
Single stage power factor corrected (SSPFC) AC-DC converters are popular in industrial applications such as telecom because they are cheaper and smaller than conventional two-stage converters. The intermediate DC bus voltage of these converters, however, varies significantly when used in universal voltage range applications. A new AC-DC SSPFC resonant converter that can be operated with universal...
A grid-tied inverter can be designed to operate in boundary conduction mode or discontinuous current mode to achieve high efficiency and high power density. However, the switching frequency variation in boundary conduction mode can be a problem. Although the switching frequency in discontinuous current mode is fixed, the output current becomes distorted due to the resonant between inductor and parasitic...
This paper presents the design and experimental results of the 36-kW pulsed-power supply for the xenon flash lamp. The continuous conduction mode series-parallel resonant converter is modified. This means that not only the few hundred kilohertz of high switching frequency is introduced to replace the resonant inductor with the leakage inductor of transformer but also the high output current is accomplished...
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