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The Piezoelectric Actuator Drive (PAD) is a precise piezoelectric motor generating high-torque rotary motion, which employs piezoelectric stack actuators in a wobble-style actuation to generate rotation. The piezoelectric stacked ceramics used as the basis for motion in the motor suffer from hysteretic nonlinearities. In order to model these nonlinearities, the first-order hysteresis reversal curves...
In this paper an outphasing modulation control method suitable for line regulation of very high frequency resonant converters is described. The pros and cons of several control methods suitable for very high frequency resonant converters are described and compared to outphasing modulation. Then the modulation technique is described and the design equations given. Finally a design example is given...
The Piezoelectric Actuator Drive (PAD) is an accurate, high-torque rotary piezoelectric motor that employs piezoelectric stack actuators and inverse hypocycloidal motion to generate rotation. Important factors that determine motor performance are the proper concentric alignment between the motor ring and shaft and the similarity of the stack actuators used. This paper investigates the electromechanical...
This paper presents an analysis and comparison of isolated topologies for bidirectional fuel cell systems. The analyzed topologies are the dual active bridge (DAB) and the isolated full bridge boost converter (IFBBC). The analysis is performed based on the component stress factor (CSF). Results highlight that the DAB has lower CSF than the IFBBC for narrow converter operating points. On the other...
In this paper, a 3kW boost converter for PV applications using SiC devices is introduced. Main focus is to operate the converter over a wide range of switching frequency and to analyze the main loss distributors as well as the efficiency. The switching element is a recently introduced normally-on SiC JFET and a SiC diode is used. The SiC JFET has been evaluated on an optimized double pulse test circuit...
In renewable energy applications power conversion efficiency is major concern. This is especially true for grid-tie energy storage systems based on bidirectional dc-dc and dc-ac converters where power flows through these system components. Latest developments in power semiconductors technology significantly reduced switching and conduction losses in dc-dc and dc-ac converters allowing efficiencies...
This paper deals with the switching behavior of a SiC MOSFET in a TO-247 package. Based on simulations, critical parasitic inductances in the circuit layout are analyzed and their effect on the switching losses highlighted. Especially the common source inductance, a critical parameter in a TO-247 package, has a major influence on the switching energy. Crucial design guidelines for an improved double...
In an isolated power supply, the inter-winding parasitic capacitance plays a vital role in the mitigation of common mode noise currents created by fast voltage transient responses. The lower the transformer inter-winding capacitance, the more immune the power supply is to fast voltage transient responses. This requirement is even more critical for modular stacking applications in which multiple power...
The Piezoelectric Actuator Drive (PAD) is a type of rotary motor that transforms the linear motion of piezoelectric stack actuators into a precise rotational motion. The very high stiffness of the actuators employed make this type of motor suited for open-loop control, but the inherent hysteresis exhibited by piezoelectric ceramics causes losses. Therefore, this paper presents a straightforward method...
This paper deals with a 3kW multilevel inverter used for PV applications. A comparison has been made based on simulations using IGBTs and SiC MOSFETs to see how much efficiency can be gained when SiC diodes are used. A prototype with the same IGBTs and SiC MOSFETs has been built but using regular soft-recovery Si diodes instead of SiC diodes. Efficiencies and switching transitions for different switching...
This paper presents a design and optimization of a high current planar transformer for very high efficiency dc-dc isolated boost converters. The analysis considers different winding arrangements, including very high copper thickness windings. The analysis is focused on the winding ac-resistance and transformer leakage inductance. Design and optimization procedures are validated based on an experimental...
Renewable energy sources are fluctuating depending on the availability of the energy source. For this reason, energy storage is becoming more important and bidirectional fuel cells represent an attractive technology. Fuel cells require high-current low-voltage dc-dc or dc-ac converters as power interface to the grid. In power electronics, the converter efficiency is characterized at fixed operating...
In this paper a new control-interface card for developing simple control loops and generating test signals for power electronic converters is presented. The control board can operate with two computational cores (Texas Instruments and Microchip) allowing using the preferred DSP architecture and development environment. Moreover, the interface board can operate with open hardware Arduino-like boards...
The paper describes the design of three different structures for printed circuit board embedded inductors. Direct comparison of spirals, solenoids and toroids are made with regard to inductance, dc and ac resistance, electromagnetic field and design flexibility.
Silicon Carbide (SiC) power devices can provide a significant improvement of power density and efficiency in power converters. The switching performances of SiC power devices are often a trade-off between the gate driver complexity and the desired performance; this is especially true for SiC BJTs and JFETs. The recent introduction of SiC MOSFET has proved that it is possible to have highly performing...
In power electronics there is a general trend to increase converters efficiencies and power densities; for this reason new power semiconductors based on materials such as Silicon Carbide (SiC) and Gallium Nitride (GaN) are becoming more popular. This is especially valid for renewable energies applications where the generated energy has a higher cost than with conventional energy sources. This paper...
The ongoing demand for smaller and lighter power supplies is driving the motivation to increase the switching frequencies of power converters. Drastic increases however come along with new challenges, namely the increase of switching losses in all components. The application of power circuits used in radio frequency transmission equipment helps to overcome those. However those circuits were not designed...
This paper studies the double open-switch fault issue occurring within the conventional matrix converter driving a three-phase permanent-magnet synchronous motor system and proposes a fault-tolerant solution by introducing a revised modulation strategy. In this switching strategy, the rectifier-stage modulation is adjusted based on the knowledge of the switching logics of the inverter-stage and the...
Modern power semiconductors allow for switching frequencies of power converters in the very high frequency (VHF) band (30 MHz to 300 MHz). The major advantage of this frequency increase is a remarkable reduction of the size of power converters due to smaller passive components. However crucial attention needs to be payed to switching losses, so that the size reduction in electrical components does...
This paper presents an overview of most promising power electronics topologies for a fuel cell hybrid power conversion system which can be utilized in many applications such as hybrid electrical vehicles (HEV), distributed generations (DG) and uninterruptible-power-supply (UPS) systems. Then, a multiple-input power conversion system including a decoupled dual-input converter and a three-phase neutral-point-clamped...
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