2002 IEEE 33rd Annual IEEE Power Electronics Specialists Conference. Proceedings (Cat. No.02CH37289)

The resonant dual-output converter (RDOC) is derived from the series-parallel resonant LLC converter by introducing half-wave instead of full-wave rectification. The RDOC regulates two outputs independently using a single power stage. The load range covers any combination including no-load while still maintaining zero voltage switching. This holds for an input voltage range comparable to the conventional LLC converter. The RDOC can further be operated at different secondary voltages per turn in order to meet specific low voltage load requirements. A control structure is outlined that transfers the original error signals into two actuating signals which then separately control frequency and duty cycle.

Emerging needs in the automotive area are being turned toward a decrease of design times of power converters. The purpose of this paper is to present a global methodology to design power electronics equipment. Instead of solving each step successively, all problems are taken into account simultaneously. The main difficulty consists in evolving simple analytical (or semianalytical) models for the different phenomena. After implementation in a Matlab/spl reg/ environment, the design consists in solving an optimization problem, under constraints. This paper compares several model accuracy, as well as various optimization methods in the case of a 42V-14V DC-DC converter.

Railway traction loads present large single phase loads to the supply system. Typically zero sequence components are removed using a phase to phase transformer connection, however a large negative sequence component remains. As the amount of rail traffic increases and the use of regenerative braking becomes higher, the issue of negative sequence becomes more critical. This paper presents a novel active filter approach to negative sequence compensation using single phase compensators at the track side of the system. The compensators for two separate track sections share a common DC bus, which allows power transfer between the sections. A control algorithm based on synchronous reference frame theory is proposed, with modified transformations to reflect the two phase nature of the system. The topology and control algorithm are verified using simulation and results are shown.

This paper presents high voltage (HV) NMOS based level shifters, bootstraps and charge pumps in direct and cascaded topologies, which are highly useful to implement either power integrated circuits (PICs) high-side transistor floating drives or compact inductorless DC-DC power supplies. Monolithic solutions resorting to a unique HV NMOS switching cell are very important when standard CMOS technologies are intended to be used. In fact, these floating drives are fully CMOS compatible. Even while using a dedicated PIC technology this approach is a cost effective one. Furthermore, topologies based on a unique HV NMOS can be implemented in regular and simple geometry, thus, they are prone to be easily configured by top metal layers and to pave the way to mask configurable PICs. Simulation and experimental results obtained for a level shifter, a bootstrap and a charge pump used either as voltage multiplier or as a floating voltage source are presented and discussed. These low cost solutions are highly desirable for mobile applications power management and an efficient drive either for PICs or for intelligent devices.

In this paper, a power converter with an auxiliary circuit, which has no snubber loss, has been suggested to reduce the diode reverse recovery loss. The small saturable inductor is added to reduce the reverse recovery loss of the diode. Due to the addition of a saturable inductor, much resonant energy is reduced. Therefore, the resonant capacitor can be significantly reduced. Therefore, higher frequency operation of the converter has been achieved. In battery discharger applications, the converter frequency is increased to as high as 400 kHz at 48 V/sub DC/, 2.5 A/sub DC/ load for about 22-34 V/sub DC/ battery voltage. The efficiency is about 96% for a nominal input voltage of 28 V/sub DC/. The characteristics and operations are verified by experiments.

Inductive heating applications, such as pipe welding or steel-tape annealing, require electrical power ratings of several MWs at frequencies up to 100 kHz and higher. To realize this high power frequency product, several inverters or several power semiconductor devices have to be connected in parallel, because the maximum rating of a single inverter unit is often far below the required rated power. In this paper, a control strategy for parallel connected soft-switching (ZVS and near ZCS) high-frequency voltage-source IGBT- or MOSFET-inverters is presented. The proposed distributed control system, where one control unit is dedicated to each inverter, ensures synchronous switching without any communication between individual control units. Distinctive features include high reliability, flexible configurations, reduction of long communication lines and good monitoring properties.

The performance of a 600 V, 4 A silicon carbide (SiC) Schottky diode (Infineon SDP04S60) is experimentally evaluated. A 300 W boost power factor corrector with average current mode control (PFC) is considered as a key application. Measurements of overall efficiency, switch and diode losses and conducted electromagnetic interference (EMI) are performed both with the SiC diode and with two ultra-fast, soft-recovery, silicon power diodes, namely the RURD460 and the recently presented STTH5R06D. The paper compares the results to quantify the impact of the recovery current reduction provided by SiC diode on these key aspects of the converter behavior.

This paper describes the developments at the University of Minnesota of new approach in teaching of electric drives, focusing on the associate state-of-the-art laboratory. The mission of these developments is to nationally revitalize courses in industrially and strategically vital fields of electric drives (and power electronics). This is accomplished by making these courses appealing to students (undergraduate enrollments have significantly increased subsequent to adopting these approaches) where they receive a first-rate education in just one undergraduate course in a way that ensures a seamless continuity to advanced courses. The laboratory is based on a dSPACE development board and several custom designed power converter boards and electric motors, working on a 42 V DC-bus voltage system.

This paper first analyzes the required characteristics of common-mode (CM) chokes for induction motor (IM) drive applications. It then presents an approach for specifying CM chokes in order to achieve specified CM-current reductions. To this end, a high-frequency IM model based on the IM zero-sequence impedance is suggested. The CM choke specification should be based on its particular application due to the unique characteristics of the CM currents. The ideas are verified by laboratory experiments.

A family of minimum-voltage active-clamping (MVAC) DC-DC converters is proposed. Differing from the conventional active-clamping converters, MVAC DC-DC converters possess minimum voltage stresses. There is no parasitic voltage ringing across the diode of the converters. Both main switch and auxiliary switch in the MVAC converters can achieve zero-voltage-switching (ZVS) under wide operation range. Operation principle and analysis of a MVAC boost converter are explained as an example of the MVAC DC-DC converters. A MVAC boost converter rated at 1 kW is built to verify the operation and the analysis.