Xinjie Yu

STRETCH Meat Grinder With ICCOS

Inductive pulse power supplies attract interests since their energy densities are one order of magnitude higher those of capacitive ones at the same power-output capacity. IAT (Institute of Advanced Technology) put forward an inductive pulse power topology called STRETCH (Slow Transfer of Energy Through Capacitive Hybrid) meat grinder. In this topology, an active switch is used to cut off the charging current. Limited by the cutting off current ability of IGCT, it may encounter difficulties in extending to higher energy systems. Other than that, the cost of the system is very high. In this paper, the principle of STRETCH meat grinder is presented firstly. Then the STRETCH meat grinder with ICCOS (Inverse Current Commutation with Semiconductor devices), which was proposed by German-French Institute of Saint Louis (ISL), is proposed. The process of ICCOS in STRETCH meat grinder is illustrated in details. Finally, simulations are made based on Simplorer®8 to explain how ICCOS works clearly. A preliminary discussion of how to design ICCOS is also presented. And we come to a conclusion that the STRETCH meat grinder with ICCOS exceeds the limitations of the original one and has potential applications for high energy systems in the future while cutting down the cost greatly.

Comparisons of Three Inductive Pulse Power Supplies

The energy density of the inductive energy storage systems is one order of magnitude higher than that of the capacitive ones. Therefore, they have potential applications in the future. In this paper, three inductive pulse power supply (PPS) topologies, i.e., slow transfer of energy through capacitive hybrid meat grinder, XRAM, and nonmutual inductance PPS, are discussed in depth. First, their principles are analyzed. Then, simulations are made to illustrate the principles and prepare the fundamental data for further comparisons based on a 4-kA charging current, 220-μH total inductance system under the environment of Simplorer 8. Five performance indices reflecting their performances from different aspects are proposed in order to ensure objective and comprehensive comparisons. Based on those indices, the advantages and disadvantages of these topologies are pointed out and some potential improvements are also presented.

Simulation and Two-Objective Optimization of the Electromagnetic-Railgun Model Considering VSEC Resistance and Contact Resistance

A novel electric-circuit simulation model considering the contact and interface physics for electromagnetic railgun is suggested. The contact velocity skin-effect resistance and the contact resistance are considered. The pulsed-power supply is implemented with Simplorer V8, and the railgun is modeled by Matlab/Simulink. The data exchange is controlled by Simplorer V8. Nine experimental data have been used to validate the new model. Then, based on the validated model, a two-objective optimization pursuing both the highest velocity and the highest efficiency is carried out with the help of iSIGHT.

Structural Parameter Optimization of Inductors Used in Inductive Pulse Power Supply

Structural parameters directly affect the energy density and the total resistance of the inductors used in inductive pulse power supply (IPPS). This paper elaborates the relationship between the structural parameters and electrical performances of the inductors used in IPPS and set up the inductors for the experiment in slow transfer of energy through capacitive hybrid meat grinder circuit using air-core flat spirals of strip coil. Then we compile a program that can obtain the structural parameters of the inductors that have the highest energy density under the condition of given charging and discharging currents as well as inductances in the primary and secondary sides. The calculation results of the program are analyzed and verified by the measured values of the real inductors. At the end, on the condition of a constant current density, we put forward a rule that along with the increase in the system energy, the energy density of the IPPS became higher and the resistance of the inductors became lower.

Structural parameters optimization for the inductors used in the inductive pulse power supply

The structural parameters directly affect the energy density and the total resistance of the inductors used in the inductive pulse power supply (IPPS). In this paper, we expound the relationship between the structural parameters and electrical performances of the inductors used in IPPS, and introduce the implementation of the inductors for the experiment in Slow TRansfer of Energy Through Capacitive Hybrid (STRETCH) meat grinder circuit using Air-core Flat Spirals of Strip Coil (AFSSC). Then, we work out a program which can obtain the optimal structural parameters of the inductors with the highest energy density under the condition of providing the charging and discharging current as well as the inductance in the primary and the secondary side. The correctness of the program is verified by the measured values of the real inductors. At the end, on the condition of constant current density, we put forward a rule that along with the increase of system energy, the energy density became higher and the resistance of the inductors became lower.

Comparisons of three inductive pulse power supplies

The energy density of the inductive energy storage systems is one order of magnitude higher than that of the capacitive ones. Therefore they have potential applications in the future. In this paper, three inductive pulse power supply topologies, i.e. STRETCH meat grinder, XRAM, and non-mutual inductance pulse power supply, are discussed in depth. Firstly, their principles are analyzed. Then simulations are made to illustrate the principles and prepare the fundamental data for further comparisons based on a 4 kA charging current, 220μH total inductance system under the environment of Simplorer®8. Five vital indices reflecting their performances from different aspects are proposed in order to ensure objective and comprehensive comparisons. Based on those indices, the advantages and disadvantages are pointed out and some potential improvements are also presented.

STRETCH meat grinder with ICCOS

Inductive pulse power supplies are of interest because their energy densities are one order of magnitude higher than those of capacitive power supplies, based on the same power-output capacity. The Institute of Advanced Technology puts forward an inductive pulse power topology called the slow transfer of energy through capacitive hybrid (STRETCH) meat grinder. In this topology, an active switch is used to cut off the charging current. Limited by the current turning off ability of integrated gated commuted thyristor, it may encounter difficulties in extending to higher-energy systems. Other than that, the cost of the system is very high. In this paper, the principle of the STRETCH meat grinder is presented. Then, the STRETCH meat grinder with inverse current commutation with semiconductor devices (ICCOS), which is proposed by the Institute of Saint Louis, is presented. The process of ICCOS in the STRETCH meat grinder is illustrated in detail. Finally, simulations are made based on Simplorer 8 to explain how ICCOS works clearly. A preliminary discussion of how to design ICCOS is also presented. We conclude that the STRETCH meat grinder with ICCOS removes the limitations of the original one and has potential applications for high-energy systems in future and can cut down the cost greatly.

Determining Key Parameters for the STRETCH Meat Grinder Circuit

STRETCH (Slow Transfer of Energy Through Capacitive Hybrid) meat grinder circuit, which was proposed by IAT (Institute for Advanced Technology), added a capacitor into the traditional meat grinder circuit. Even though its energy density is slightly less than the corresponding pure inductance system, it can reduce the voltage across the opening switch and maintain high multiplication factor of the opening current. The performance of the STRETCH meat grinder depends on multiple parameters. The inductance ratio (n=L1/L2) and the capacitance(C) are two vital factors, which have a crucial influence on the system performance, such as the voltage over the main switch (VSopm), the current multiplication factor (m) and the ratio of the maximum capacitive energy over the total inductive energy (η). Thorough studies have been carried out in this paper on the relationship between the above two factors and the three performance criteria. This paper also discusses and analyzes the chosen of key parameters (n and C) for a single-stage STRETCH meat grinder with 2mH total inductance, which is made up of two serial coils with 0.95 coupling factor. The opening current of the main switch is 1kA, which constitutes a 1kJ inductive pulsed-power supply. It fully takes the advantage of the STRETCH meat grinder topology, intensifies the study of the inductive pulsed-power supply with higher energies, and is easy to be utilized for practical application.

A Slice-Type Magnetoelectric Laminated Current Sensor

This paper describes the design and the implementation of a new structure for an ac current sensor based on a magnetoelectric laminated composite slice. Two layers of longitudinally magnetized magnetostrictive material Terfenol-D (Tb0.3Dy0.7Fe1.92) and one layer of transversely polarized piezoelectric material Pb(Zr,Ti)O3 (PZT) were epoxy-bonded and the wire conducting the current coiled along the slice and the output voltage obtained across the two surfaces of the PZT. Compared with the reported ring-type or close-magnetic-circuit-type magnetostrictive current sensor topologies, there was no requirement for any interruption of the power supply to enable the installation and the maintenance of the sensor, which was very convenient and practical. The dimensions of the slice sensor were 30 mm × 8 mm × 2.8 mm. An averaging method was used to perform the theoretical analysis and the simulation is carried out using the COMSOL multiphysics software. The analysis, simulation, and experimental results were compared thoroughly. The current sensitivity was 1.03 mV/mA over input currents ranging from 15 mA to 2.1 A. A stable output voltage over a frequency range from 20 Hz to 5 kHz was attained by the slice. Further research on the influence of the dc bias magnetic field and the number of turns of the current coil on the output characteristics of the sensor has been carried out. This current sensor has great potential for further research and applications.

The Meat Grinder With SECT Circuit

The meat grinder is a basic circuit for inductive pulsed-power supply (IPPS). Based on meat grinder, the Institute of Advanced Technology proposed a circuit called the slow transfer of energy through capacitive hybrid (STRETCH) meat grinder, in which an Integrated Gate Commutated Thyristors (IGCT) is selected as the main switch. Tsinghua University proposed the STRETCH meat grinder with inverse current commutation with semiconductor devices (ICCOS) in which the main switch is replaced by a thyristor and the ICCOS subcircuit is introduced to turn off the main switch. To reduce the opening switch voltage and increase the current turning-off capacity for IPPS, this paper presents a novel circuit topology named the meat grinder with self-charged capacitor and thyristors (SECTs). The key idea of the SECT topology is to turn off the primary current by the energy transfer capacitor, which is precharged. The meat grinder with SECT has larger capacity than the STRETCH meat grinder because it replaces the IGCT with a thyristor and is simpler than the STRETCH meat grinder with ICCOS because it only needs one capacitor. The suggested circuit is more suitable for IPPS module with high energy density. Simulation and experiment have been carried out to validate the circuit.