Showing papers by "Juan Carlos Balda published in 2006"

Extending the ZVS Operating Range of Dual Active Bridge High-Power DC-DC Converters

Abstract: A switching control strategy to extend the soft-switching operating range of the dual active bridge (DAB) dc-dc converter under the zero-voltage-switching (ZVS) operating mode is proposed. The converter topology consists of two active bridges linked by a high-frequency transformer. One drawback of this strategy is that soft-switching is only possible in a restricted converter operating region. A novel pulse width modulation strategy to extend the conventional soft-switching operating mode region and its analysis are presented in this paper. Experimental results are given in order to validate the theoretical analysis and practical feasibility of the proposed strategy.

Cancellation of common-mode Voltages for induction motor drives using active method

Abstract: This paper presents a theoretical analysis for canceling common-mode (CM) voltages for induction motor (IM) drives using a CM transformer with active circuitry. The design methodology and the practical implementation are presented for motor drives rated 460 V or higher. To verify the design approach, an implementation example and experimental results for a 460-V motor drive system are presented.

Characterization of SiC JFET for Temperature Dependent Device Modeling

Abstract: Silicon Carbide (SiC) is considered the wide band gap semiconductor material that can presently compete with silicon (Si) material for power switching devices. Compact circuit simulation models for SiC devices are of utmost importance for designing and analyzing converter circuits; in particular, if comparisons with Si devices will be performed. The SiC power switching device structure and composition inevitably differs from those of conventional Si devices so as to harness the superiority of the material. The operational characteristics of the device thus are different from those of conventional Si devices. These characteristics cannot be accurately predicted by current Si power device models. Hence, the motivation to develop circuit simulation models for SiC devices. Moreover, SiC transistors have not been characterized as thoroughly as diodes. This paper characterizes SiC JFETs for the purpose of modeling and parameter extraction which can then be utilized in circuit simulations. The characterization is based on the dc (current-voltage) characteristic measurements using a curve tracer and on the ac (capacitance [impedance] — voltage) measurements using an impedance analyzer. Noting that characterization data for SiC JFETs are only available up to an ambient temperature of 250°C, the device is characterized from room temperature to 450°C demonstrating the high temperature operation of SiC JFETs. To this end, the devices were packaged in dedicated high temperature packages, and measurement fixtures were specially fabricated to withstand high ambient temperatures. The body diode buried in the evaluated SiC JFET is also characterized for potential synchronous rectifier applications.

Characterization of SiC diodes in extremely high temperature ambient

Abstract: This paper discusses the static and dynamic behavior of the body diode buried in SiC JFETs and SiC Schottky barrier diodes (SBDs). The device parameters are extracted from experimental results and their temperature dependencies are discussed. There is reverse current flow from source to drain in the channel of JFETs for on condition at low temperatures. In higher temperatures, it tends to flow through the body diode due to the increase of the resistance across the channel. The dynamic characteristics indicate that the reverse recovery phenomena of the body diode in a SiC JFET deteriorates with increasing temperature. It is therefore desirable to add an external SiC SBD for improving the static and dynamic behavior for high temperature operation of SiC JFETs.

Analysis of Three-Level ZVS PWM Inverter for Induction Heating Applications

Abstract: This paper presents an operation analysis of a high frequency three-level (TL) PWM inverter applied for an induction heating applications The feature of TL inverter is to achieve zero-voltage switching (ZVS) at above the resonant frequency The circuit has been modified from the full-bridge inverter to reach high-voltage with low-harmonic output The device voltage stresses are controlled in a half of the DC input voltage The prototype operated between 70 and 78 kHz at the DC voltage rating of 580 V can supply the output power rating up to 3000 W The iron has been heated and hardened at the temperature up to 800degC In addition, the experiments have been successfully tested and compared with the simulations