Showing papers by "Juan Carlos Balda published in 2003"

Comparing DC-DC converters for power management in hybrid electric vehicles

Abstract: The design of DC-DC converters for power electronic interfaces in power management systems for hybrid electric vehicle (HEV) is a very challenging task. To this end, this paper presents an analysis, design, and comparison study of several bi-directional non-isolated DC-DC converter topologies that could be considered potential candidates for the power electronic interface of HEV energy/power sources, in particular an ultracapacitor pack. The considered topologies are the half-bridge, Cuk, SEPIC, and Luo converters. The analysis and design of the converters is performed throughout equations for the stresses of the active and passive components. The comparison study, achieved by means of graphs where the variables of interest are plotted as a function of the voltage ratio Vo/Vi, uses the half-bridge converter as the base case. Particular attention is paid to the stresses of the active and passive components due to the wide input voltage requirements typical of this load-leveling or power-management application.

Design methodology of a combined battery-ultracapacitor energy storage unit for vehicle power management

Abstract: Hybrid and electric vehicles (HEV, EV) require some form of energy storage in order to achieve load leveling or efficiently manage power flows, mainly when accelerating or decelerating. Traditionally, batteries have been used but recently ultracapacitors have become potential candidates for energy storage in HEV/EV applications. To this end, this paper first presents a methodology for determining whether an energy storage unit (ESU) should consist of only batteries, only ultracapacitors or a combination of both. An example illustrates the feasibility of the proposed ideas. Finally, the paper concludes with a cost analysis of the different ESU alternatives.

The role of ultracapacitors in an energy storage unit for vehicle power management

Abstract: This paper extends a design methodology for a combined battery-ultracapacitor energy storage unit (BU-ESU) for vehicle power management into two areas. First, the model of the half-bridge converter replaces the generic models of the dc/dc converters used in the BU-ESU. This model is capable of determining the electric stresses present on the active and passive components during the operation of the vehicle. Second, an improved BU-ESU control strategy applicable to all operating conditions of the vehicle is determined. This control strategy is used to resize the BU-ESU. Finally, the vehicle fuel consumptions achieved when using this newly resized BU-ESU are compared using ADVISOR simulation results with those obtained for the BU-ESU designed in R.M. Schupbach et al. (June 2003).

A PV dispersed generator: a power quality analysis within the IEEE 519

Abstract: The use of environmentally clean photovoltaic (PV) dispersed generation will become more widespread in the future due to anticipated cost reductions in PV technology. This paper summarizes the results of a power quality (PQ) study performed on a PV generator in order to estimate the effects that inverter-interfaced PV dispersed generation might have upon the quality of electric power. Different interpretations of the harmonic distortion limits set in the IEEE 519-1992 standard are performed together with a comparison with the BC Hydro's harmonic current limits. This paper also includes a statistical analysis of all measurements recorded with the help of two PQ monitors, an evaluation of the results from a connection/disconnection test, and harmonic simulation results.

Minimization and cancellation of common-mode currents, shaft voltages and bearing currents for induction motor drives

Abstract: This paper presents the theoretical analyses and experimental comparisons of different solutions aimed at minimizing and canceling common-mode (CM) currents, shaft voltages and bearing currents. In particular, it discusses the use of CM chokes for minimizing CM currents; illustrates the use of a shaft-grounding method combined with a CM choke; analyzes the effectiveness of the "passive" method of the CM transformer (CMX); and evaluates the "active" method of the CMX that effectively cancels the CM voltages (and thus simultaneously the CM currents, shaft voltages and bearing currents). The latter is the best solution to both CM (EMI) and bearing current problems at the expense of being the most costly. Experimental results are presented to substantiate the theoretical analyses.

Analysis of conducted EMI emissions on a soft-switched full bridge dc-dc converter with a fixed switching frequency

Abstract: This paper presents a comparative study between a soft-switched full bridge DC-DC converter using phase-shifted pulse-width-modulation (PSFB-PWM) and another one with PWM control without phase-shifted strategy. The converter using phase-shifted control achieves zero-voltage and zero-current switching (ZVZCS), whereas the other without using phase-shifted control achieves ZVS. The paper describes the operating characteristics and analyzes the performance of both circuits, includes a comparison of conducted electromagnetic interference (EMI) emissions from both converters, and provides experimental results that are in good agreement with the theoretical ones.

An improved zero-voltage and zero-current-switching PWM full-bridge DC-DC converter

Abstract: An improved isolated zero-voltage and zero-current switching full-bridge pulse width modulation (ZVZCS-FB-PWM) DC-DC converter having dual voltage outputs of 42 V and 5 V are presented. The leading leg achieves zero voltage switching, and the lagging leg with a series diode and active snubber circuit achieves zero current switching. A phase-shifted (PS) PWM technique is used to obtain ZVZCS by equalizing the small dead times. Also, PS-PWM strategy with a robust average current-mode control can regulate the output voltage to obtain stability and reliability. Furthermore, the active snubber circuit is replaced with a flyback converter operated in the ZVS discontinuous conduction mode due to the ringing voltage of the fast recovery diodes in the secondary side. The steady-state analysis of the topology is illustrated. In this paper, simulated and experimental results are shown to verify the validity of the proposed concept. Moreover, this configuration and results in lower conduction losses in the primary side are well suited for applications above a few kilowatts.

Active cancellation of common-mode voltages on drives rated 460-V and higher

Abstract: This paper presents a theoretical analysis of the "active circuitry" for a common-mode (CM) transformer to cancel CM voltages. The design methodology, and the practical Implementation issues are presented for motor drive systems rated 460 V or higher. An implementation example and experimental results for a 460-V motor drive system illustrate the feasibility of the proposed ideas.