Input and output total currents characterization in BCM and CCM Interleaved Power Converters Under Inductance Mismatch

This paper presents a complete characterization of input and output currents in interleaved power converters with inductance mismatch, operating in Boundary Conduction Mode (BCM) and Continuous Conduction Mode (CCM). The proposal allows to compute these currents in several interleaved converter topologies for the entire range of operating points, considering any number of phases and any inductance ratio. Input and output currents are recovered from the values obtained when adding the phase currents in the instants where the slopes change; values that are thus defined as key points. This methodology is based on the coincidences that exist between the instants of the phase current key points and those of total currents. By using the computed key points, ripple amplitude, rms value and harmonic content of input and output total currents for the entire range of operating points can be easily obtained. Simulations are conducted on a 5-phase boost converter and a 5-phase buck converter under different conditions in order to validate the proposal expressions. Experimental tests on a 5- phase buck converter are presented under different operation conditions to verify that the proposed method can be applied in real situation.Fil: Cervellini, María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Científicas y Tecnológicas en Electrónica. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones Científicas y Tecnológicas en Electrónica; ArgentinaFil: Carnaghi, Marco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Científicas y Tecnológicas en Electrónica. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones Científicas y Tecnológicas en Electrónica; ArgentinaFil: Antoszczuk, Pablo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Científicas y Tecnológicas en Electrónica. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones Científicas y Tecnológicas en Electrónica; ArgentinaFil: Garcia Retegui, Rogelio Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Científicas y Tecnológicas en Electrónica. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones Científicas y Tecnológicas en Electrónica; ArgentinaFil: Funes, Marcos Alan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Científicas y Tecnológicas en Electrónica. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones Científicas y Tecnológicas en Electrónica; Argentin

Grid inductance estimation by reactive power perturbation for sensor-less scheme based on virtual flux

Use of renewable energy sources is raising for grid connected systems, for which higher power quality requirements are being issued. Monitoring the grid impedance ensure stable operation of the controller and proper connection and disconnection from the grid. Thus it is vital to know the value of grid or transformer distributed impedance in given time, instead assuming a constant value in controller. To overcome this problem an identification method based on perturbation of reactive power is proposed. The normally inductive character of the grid used together with synchronous frame current controller have cross coupling terms which are used in analysis. This method is suitable for use with virtual flux oriented control. It uses two current sensors and one dc link voltage sensor. Method enables maintain unity power factor not only at PCC but also further into the grid, including lines and transformer leakage inductance.reviewe

The current unbalance in stacked REBCO tapes -- simulations based on a circuit grid model

Unlike low temperature superconducting cables, there is so far no perfect solution for REBCO coated conductors to form a fully transposed high current cable. Every REBCO cable concept must import a stack of tapes to achieve an operating current as high as tens of kiloamperes. The stacked REBCO tapes, no matter whether they are twisted or not, however, have a nature of non-transposing and therefore could result in current unbalance. In this manuscript, the current unbalance and the related electrical characteristics of a cable made of 40 stacked REBCO tapes are studied with an electrical circuit simulation. The differences in splice resistances and tape inductances that are both related to the non-transposed structure of a REBCO stack are considered. Results show that for a 40 cm long termination, a proper method to keep the contact resistivity between each tape and the copper termination around 1e-8 ohmm is crucial to totally avoid current unbalance lowering the cable performance. Surprisingly, the inter-tape current transfer is found to be able to further exacerbate local high current though it does make the overall distribution more balanced. The inductance difference induced current unbalance is only important if local defects exist at long REBCO tapes, which on the other hand can be cured by good inter-tape current transfer. For a fast-charging rate of 1 kA/s, the inter-tape contact resistivity should also be low to a level of 1e-8 ohmm to ensure a short current transfer length of around 1 m

The design of a multilevel envelope tracking amplifier based on a multiphase buck converter

Envelope Tracking (ET) and Envelope Elimination and Restoration (EER) are techniques that have gained in importance in the last decade in order to obtain highly efficient Radio Frequency Power Amplifier (RFPA) that transmits signals with high Peak to Average Power Ratio (PAPR). In this work a multilevel multiphase buck converter is presented as a solution for the envelope amplifier used in ET and EER. The presented multiphase buck converter generates multilevel voltage using “node” duty cycles and non-linear control. In this way the multilevel is implemented using only one simple power stage. However, the complexity of the multilevel converter implementation has been shifted from complicated power topologies to complicated digital control. Detailed discussion regarding the influence of the design parameters (switching frequency, output filter, time resolution of the digital control) on the performance of the proposed envelope amplifier is presented. The design of the output filter is conducted fulfilling the constraints of the envelope slew rate and minimum driver pulse that can be reproduced. In the cases when these two constraints cannot be fulfilled, they may be relieved by the modified control that is presented and experimentally validated. Finally, in order to validate the concept, a prototype has been designed and integrated with a nonlinear class F amplifier. Efficiency measurements showed that by employing EER it is possible to save up to 15% of power losses, comparing to the case when it is supplied by a constant voltage. Additionally, Adjacent Channel Power Ratio (ACPR) has been measured. The obtained results showed the value higher than 30dB for signals up to 5 MHz of bandwidth, without using predistortion technique

Magnetic Calorimeter Option for the Lynx X-Ray Microcalorimeter

One option for the detector technology to implement the Lynx x-ray microcalorimeter (LXM) focal plane arrays is the metallic magnetic calorimeter (MMC). Two-dimensional imaging arrays of MMCs measure the energy of x-ray photons by using a paramagnetic sensor to detect the temperature rise in a microfabricated x-ray absorber. While small arrays of MMCs have previously been demonstrated that have energy resolution better than the 3 eV requirement for LXM, we describe LXM prototype MMC arrays that have 55,800 x-ray pixels, thermally linked to 5688 sensors in hydra configurations, and that have sensor inductance increased to avoid signal loss from the stray inductance in the large-scale arrays when the detectors are read out with microwave superconducting quantum interference device multiplexers, and that use multilevel planarized superconducting wiring to provide low-inductance, low-crosstalk connections to each pixel. We describe the features of recently tested MMC prototype devices and simulations of expected performance in designs opti- mized for the three subarray types in LXM

Electromagnetic Analysis of Solenoid Coil in ANSYS and IES Software : Case Study

The aim of this paper is to get theory technical knowledge of designing a electromagnetic solenoid coil and ogy of verifying induced current in solenoid coil by using ANSYS Software and IES software. For this purpose a 0.3 T coil has been designed with a Poloidal shaped 1500 turn outer coil of 200 cm diameter. To verify such induced current analysis is a challenging task, theoretically which can be equally calculated by a FINITE ELEMENT ANALYSIS package and IES (Integrated Engineering Software) , so a same dimension, assembly and has been modeled and meshed in ANSYS 11.0 FEA package and IES (integrated engineering software) with same load data as given in the software. Theoretical and Simulation results have been compared

Robust Deadbeat Predictive Power Control with a Discrete-Time Disturbance Observer for PWM Rectifiers under Unbalanced Grid Conditions

© 2012 IEEE. This paper presents a robust deadbeat predictive power control (DPPC) for pulsewidth modulation (PWM) rectifiers with the consideration of parameter mismatches under unbalanced grid conditions. First, conventional DPPC is modified to extend its application to both ideal and unbalanced grid conditions. Second, a tracking error of the modified DPPC with inaccurate grid-side impedance is analyzed. Third, a discrete-time power disturbance observer (DPDO) is designed to achieve accurate power control with mismatched parameters. The designed DPDO can predict complex power at the next sampling instant and estimate system disturbance simultaneously. Therefore, the DPDO can contribute to eliminate the steady-state tracking error resulting from disturbances caused by inaccurate parameters and compensate one-step delay in digital implementation. Although satisfactory steady-state performance can be obtained with modified DPPC and DPDO, transient performance still deteriorates significantly with an inaccurate value of the grid-side inductance. Thus, an online adaptive method to estimate mismatched inductance is finally developed based on the proposed DPDO. Both DPPC and DPDO are implemented in the stationary reference frame without coordinate transformation. Theoretical analysis confirms that the proposed DPDO can track disturbance without phase lag or magnitude error. Experimental tests and comparative studies with a prior DPPC on a two-level PWM rectifier validate the effectiveness of the proposed scheme

Static Current Unbalance of Paralleled SiC MOSFET Modules in the Final Layout

Silicon Carbide (SiC) MOSFETs enable enhanced performance of power converters in several applications. Parallel connection of SiC MOSFETs become mandatory for medium power applications due to the current rate of existing modules. A balanced current sharing between paralleled MOSFETs is desired to maximize the power capability of each device, maximizing the power capability of the whole system. This work studies the static current unbalance of two paralleled 1200V-400A SiC MOSFET modules with individual gate driver. Experimental measurements are done focused on parasitic inductance caused by electromechanical layout