Showing papers by "Juan Carlos Balda published in 2004"
20 Jun 2004
TL;DR: In this article, the design of a half-bridge DC-DC converter for the power electronics interface of energy storage units for a fuel-cell sport utility vehicle (SUV) is discussed.
Abstract: The work presented in this paper focuses on the design of a half-bridge DC-DC converter for the power electronics interface of energy-storage units for a fuel-cell sport utility vehicle. Several design options are explored; namely: single stage vs. multiple interleaved stages, and continuous vs. discontinuous conduction mode. These design options are weighed against the design goals of minimum cost, high efficiency at low output power levels, and minimum volume and weight to allow for high integration. Special emphasis is given to the impact that the wide input voltage requirements (i.e., from 150 V to 270 V) has on the component stresses.
42 citations
TL;DR: The experimental results show that the device can operate at 450°C, which is impossible for conventional Si devices, but the current capability of the SiC JFET diminishes with rising temperatures, and the saturation current becomes 20% at450°C with respect to the value at the room temperature.
Abstract: This paper reports on the measured dc characteristics of a SiC JFET device from room temperature up to 450°C in order to evaluate the device's capability for high-temperature operation. The authors packaged SiC JFET bare die into a dedicated high-temperature package to be able to perform experiments under extremely high ambient temperatures. The experimental results show that the device can operate at 450°C, which is impossible for conventional Si devices, but the current capability of the SiC JFET diminishes with rising temperatures. For example, the saturation current becomes 20% at 450°C with respect to the value at the room temperature.
27 citations
20 Jun 2004
TL;DR: In this article, the authors proposed a simple algorithm that recalculates the width of each PWM pulse, preserving the ideal area, taking advantage of the fact that the dead times are not always necessary, but only when the load current changes its sign.
Abstract: The output voltage of PWM power inverters shows harmonic distortion due to several causes; the main ones are the modulation algorithm, nonlinearities due to the output filter, dead times, voltage drops across the switches and modulation of the dc bus voltage. The distortion is more evident when using low dc bus voltages. As a result, motors driven by these inverters have important torque pulsations. This work proposes to reduce the distortion produced by dead times and voltage drops across the switches, using a simple algorithm that recalculates the width of each PWM pulse, preserving the ideal area. The algorithm takes advantage of the fact that the dead times are not always necessary, but only when the load current changes its sign. By simulation, the THD was reduced from 18% to 0.29% in a single-phase inverter. The proposed algorithm only needs products and sums, so it is suitable for being implemented on a DSP with low processing load. Experimental results were obtained from a non-optimized laboratory prototype, showing a reduction of the THD from 17.9% to 0.59%.
15 citations
20 Jun 2004
TL;DR: In this article, an ultracapacitor pack in parallel with the starter motor and a unidirectional dc-dc converter allows optimal charging of the pack, while load leveling of the vehicle electric accessories, and hence improved voltage regulation, is provided to the vehicle power system at a cost by adding to the converter the bi-directional power flow feature.
Abstract: A standard light ignition (SLI) battery, the vehicle energy storage element, must deliver maximum energy and maximum power. These design requirements are self-excluding; consequently, compromises must be made in the battery design. Increasing energy demands of the vehicle electric accessories are moving this technology towards its limits. New SLI battery designs are not providing the required energy density and cold cranking capabilities (i.e., maximum power) at temperatures as cold as -40 /spl deg/F. This paper explores a solution that uses an ultracapacitor pack in parallel with the starter motor and a unidirectional dc-dc converter allows optimal charging of the pack. The service battery could contribute a portion of the starter motor power using the converter. Lastly, load levelling of the vehicle electric accessories, and hence improved voltage regulation, can be provided to the vehicle power system at a cost by adding to the converter the bi-directional power flow feature.
5 citations
21 Oct 2004
TL;DR: In this paper, the integration of three-phase brushless DC motors and advanced microelectronic packaging techniques into compact motor controllers is discussed, with the primary focus on the reduction of thermal resistance.
Abstract: This work focuses on technical barriers to the implementation of controllers for auxiliary electric motors for automotive applications. It addresses the integration of three-phase brushless DC motors and advanced microelectronic packaging techniques into compact motor controllers. The proposed packaging techniques are focused on thermal performance utilizing minimum supplemental cooling. The primary focus of this discussion is the reduction of thermal resistance by the elimination of interfaces between the power devices and the heat sink. The initial application of this work is targeted at variable speed compressors for 42 V vehicles.
3 citations
02 Nov 2004
TL;DR: In this article, the authors present a method for accurate measurement of the source and line impedance of an AC power line, which is made possible primarily due to the increasing speed of analog to digital converters.
Abstract: The impedance preceding a motor driver circuit has always been a concern to those who manufacture the motor drives. A method is presented which will allow for accurate measurement of the source and line impedance of an AC power line. This has been made possible primarily due to the increasing speed of analog to digital converters. The design and error analysis of measuring the source and line impedance is presented.
2 citations
20 Jun 2004
TL;DR: In this paper, the authors proposed a novel method to generate a sinusoidal waveform for synthesizing a reference current in certain applications of parallel active power filters based on the behavior of a three-dimensional dynamical system, avoiding employing the usual combination of look up table and PLL.
Abstract: This paper proposes a novel method to generate a sinusoidal waveform for synthesizing a sinusoidal reference current in certain applications of parallel active power filters. The method, based on the behavior of a three-dimensional dynamical system, avoids employing the usual combination of look up table and PLL found in most parallel active filters synthesizing a sinusoidal source current. The method produces two high-quality sinusoidal waveforms in quadrature, applicable to those parallel active filters whose control methodology is in the /spl alpha///spl beta/ frame, or alternatively, three sinusoidal waveforms shifted 120 degrees from each other for designs that work in the abc frame.
2 citations
20 Jun 2004
TL;DR: In this article, the authors proposed a method to compensate instantaneous reactive power and/or active power oscillations in three-phase three-wire systems by using measurements of only two line voltages and two phase currents, without involving coordinate transformations.
Abstract: This paper proposes a new method to compensate instantaneous reactive power and/or active power oscillations in three-phase three-wire systems by using measurements of only two line voltages and two phase currents, without involving coordinate transformations. It is proved that the proposed method produces the same compensated source currents as the standard pq method.
1 citations
21 Oct 2004
TL;DR: In this article, the authors presented a "proof-of-concept" fuel cell vehicle prototype using a dynamometer-based test bench, where the main objective was the validation of design ideas regarding the combination of two different energy storage devices (i.e., batteries and ultracapacitors) into an ESU for the power management of this vehicle.
Abstract: The work presented in This work focuses on the development of a 'proof-of-concept' fuel cell vehicle prototype using a dynamometer-based test bench. The main objective of this work is the validation of design ideas regarding the combination of two different energy storage devices (i.e., batteries and ultracapacitors) into an ESU for the power management of this vehicle. The implemented prototype is a simplified and scale-down version of the designed vehicle; however, the measured results show that the vehicle could greatly benefit from the combination of energy sources that are different in nature such as batteries and ultracapacitors.