Meat Grinder Circuit Research Articles

Approaches for Rapid Calculation of the High-Order Meat Grinder Circuit Process in IPPS Systems

Approaches for Rapid Calculation of the High-Order Meat Grinder Circuit Process in IPPS Systems

Modelling and simulation on a novel meat grinder circuit for the dynamic pulsed power load

Compared with the capacitive pulsed power supply (CPPS), the inductive pulsed power supply (IPPS) is considered to have broader prospects because of its theoretically higher energy densities. Most recent researches focus on characteristics of the IPPS with a fixed load, which is rather different from practical applications from the engineering point of view. In this paper, with the purpose of preliminarily verifying the IPPS’s feasibility, the performance of the novel meat grinder circuit with a dynamic load model is presented and analysed under PSpice environment. The analysis model is based on the parameters of the four-module IPPS and the pulsed power load built in Institute of Electrical Engineering. Finally, the comparison between the IPPS and the CPPS with same initial energy is carried out.

Discussion on Topologies of Quick Response IPPS Suitable for Closed-Loop Control of EML

High energy density makes inductive pulsed power supply (IPPS), a research focus of supplies for electromagnetic launch (EML). However, in existing IPPS topologies, the charging and discharging stages of the inductors cannot be separated, so the response time of IPPS can be as long as ten or even tens of milliseconds. For this reason, the real-time closed-loop control of the output current and muzzle velocity based on IPPS is nearly impossible, which might be one of its biggest drawbacks compared to the capacitive pulsed power supply (CPPS). In this article, a novel current maintainable meat grinder (CMMG) circuit capable of fast response for EML applications is proposed, in which the antiparallel diode can provide a current maintaining path. After the inductor completes its charging process, the current can be maintained for a period of time. Thus, the circuit can be in a hot standby state and can be triggered with a very short delay. Subsequently, two commutation methods for the CMMG circuit are explored. The first one is to introduce the inverse current commutation with semiconductor device (ICCOS) branch. In its experiment with an inductance energy of 22 kJ, the circuit maintains 77% of the charging energy in the first 10 ms and is triggered successfully after 28 ms with almost zero response delay. The second method is the superconducting switching technology, based on which the CMMG with self-shutdown circuit is proposed and simulated.

A Repetitive Inductive Pulsed Power Supply Circuit Topology Based on HTSPPT

Inductive energy storage for pulsed power supplies is considered to have great potential because its energy density is 1 order of magnitude higher than that of capacitive one. Associating with the superconducting technology and the STRETCH meat grinder circuit, which proposed by the Institute of Advanced Technology, a superconducting inductive pulsed power supply (SPPS) circuit has been proposed by using an air-core high-temperature superconducting pulsed power transformer (HTSPPT) in our previous study. It can not only recapture the energy in the leakage flux and slow down the current change in inductors by using a capacitor, but also reduce the coil loss and the power requirement of the primary source by using superconducting inductors. However, it can be found that the SPPS may generate a large residual current during the discharging phase, which results in an adverse influence on the working frequency and the energy transfer efficiency of the whole system. This paper proposes a modified circuit based on the bridge current switching circuit and HTSPPT. The main principle of the circuit is that the recaptured energy in the capacitor and the residual energy in the secondary are used to precharge the primary inductor for the next cycle, which shortens the charging time, generates continuous current pulses, and improves the energy transfer efficiency. The procedure of the repetitive SPPS is analyzed in detail, and simulations are carried out to explain how the circuit works clearly.

Review of the Meat Grinder Circuits for Railguns

With inherent strengths in energy density and power density, the inductive pulsed power supplies (IPPS) have become an attractive option for the power supplies in electromagnetic launch systems. The meat grinder circuits, including the slow transfer of energy through capacitive hybrid (STRETCH) meat grinder circuit, the STRETCH meat grinder with inverse current commutation with semiconductor devices circuit, and the meat grinder with self-charged capacitor and thyristors circuit, constitute one major branch among the IPPS circuits. This paper summarizes the fundamental research work and contributions of the meat grinder circuits from the perspectives of circuit improvements, performance analysis, inductor design, module collaboration, and efficiency promotion. The future directions of single IPPS module are higher energy level, larger energy density, and higher efficiency.

XRAM Pulse Current Generator With Magnetic Flux Compression Effect

The dual representation of MARX (XRAM) pulse current generator with magnetic flux compression effect is a novel circuit for current multiplication, which has the advantages of both meat grinder and XRAM that are basic circuit topologies. It contributes to the multiplication of current in two aspects: first, increasing current by magnetic flux compression and second, the current can be increased by paralleled inductors. Compared with the standard XRAM topology, the proposed circuit topology can realize a larger factor of current multiplication more easily, and is better than the standard slow transfer of energy through capacitive hybrid meat grinder circuit topology in aspects of scalability and modularity. Meanwhile, its energy density is increased significantly, which is advantageous to the needs of actual electromagnetic launch. In this paper, theoretical analysis is done to illustrate the excellent performance of the proposed topology and preliminary experiment was conducted to demonstrate its feasibility.

Relationship Between STRETCH Meat Grinder Circuit Performances and Inductor Parameters

The slow transfer of energy through capacitive hybrid (STRETCH) meat grinder circuit is a widely used topology in inductive pulse power supply. Therefore, it is important to understand the relationship between the STRETCH meat grinder performances and the inductor parameters when improving the system performance and designing the inductor. From the perspective of inductor designing, this paper uses four indicators to present the STRETCH meat grinder performances, i.e., the charging current, the current amplification, the inductor energy density, and the discharge efficiency, and uses two indicators to present the inductor parameters, i.e., the total inductance and the ratio of the inductance $L_{1}$ to $L_{2}$ . First, the meanings of the indicators are explained or defined. Second, simulations and experiments are carried out, respectively, to analyze the trends of the four performance indicators along with the changes of two parameters indicators. Finally, both simulation and experiment results show that the increase of the total inductance leads to the decrease of the charging current and the discharge efficiency; moreover, the increase of the ratio of the inductor $L_{1}$ to $L_{2}$ leads to the increase of the current amplification and the discharge efficiency, but causes the decrease of the inductor energy density.

Design and Simulation of HTS Coils With a New Structure for an Inductive Pulsed Power Generator

Inductive pulsed power supplies (PPS) attract attention from several research institutions and scholars since the energy density of inductors is approximately one order of magnitude higher than that of capacitors. To effectively improve the output current of high-temperature superconductor (HTS) PPS and lower requirements for the switch, research studies have been done on STRETCH meat grinder circuit with HTS coils as an inductive module of XRAM. This paper mainly discusses the possibility of HTS coils applying to the STRETCH meat grinder as one of the fundamental research for PPS. With the characteristics of strong mechanical properties, high Ic, and low loss, HTS wire has become sufficiently available to build prototypes and practical instruments. This paper proposes a new coil winding structure that makes HTS coils applicable to the STRETCH meat grinder. Simulation results show that the transposition method can obtain a relative even current distribution in HTS parallel coils. By using the HTS magnet in the STRETCH meat grinder, maximum pulse current amplitude of 625 A can be obtained with a current multiplication factor of 5.2. Compared with the simulation results, experiments will be taken in the near future to verify the feasibility of the proposed coil structure and will be described in detail in further research work.

Determining Key Parameters for the STRETCH Meat Grinder Circuit

Slow transfer of energy through capacitive hybrid (STRETCH) meat grinder circuit, which was proposed by the 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 the high multiplication factor of the opening current. The performance of the STRETCH meat grinder circuit depends on multiple parameters. The inductance ratio (n = L 1 /L 2 ) and the capacitance (C) are the two vital factors, which have a crucial influence on the system performance, such as the voltage over the opening 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 the key parameters (n and C) for a single-stage STRETCH meat grinder with 2-mH total inductance, which is made up of two serial coils with 0.95 coupling factor. The opening current of the main switch is 1 kA, which constitutes a 1-kJ 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.

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.

System Implementation and Testing of the STRETCH Meat Grinder With ICCOS

By applying the principle of inverse current commutation with semiconductor (ICCOS) devices in a slow transfer of energy through capacitive hybrid (STRETCH) meat grinder system, a novel circuit topology called STRETCH meat grinder with ICCOS was proposed by the Tsinghua University in 2013. It can not only raise the amplitude of the opening current, but also reduce the cost of the STRETCH meat grinder circuit obviously by replacing the integrated gate-commutated thyristor (IGCT) with thyristor. This paper discusses the overall design, system implementation, and testing results of a STRETCH meat grinder with ICCOS system with roughly 1-kJ inductive energy. The load is a spiral coil with 1.4-mΩ resistance and 1.4-μH inductance. With closed-loop control strategy, the system detects the charging current of the inductors. When it reaches the designated value, the triggering signal for ICCOS is delivered and after the predefined delay time, the triggering signal for discharging the voltage on the pulseforming capacitor is delivered. The current of the inductors and the load are measured by Rogowski coils. The opening current is 1 kA and the maximum load current is close to 4 kA. All the voltages on the switches are lower than 1 kV. The experimental results are consistent with the simulated ones, which verified the correctness of the theoretical analysis and proved the applicability of the STRETCH meat grinder with ICCOS for larger energy level.

Enhancing the transfer of inductive energy to imploding plasma loads with a single-step meatgrinder circuit

The transfer of magnetic energy to an uncoupled load inductor using a novel inductive storage and transfer circuit (single-step meatgrinder) is compared with two classical inductive circuits. The first is the inductor-inductor transfer via an opening switch. The second is a transformer circuit where the primary circuit is opened and energy is transfered to the secondary and the uncoupled load. For identical loads the new circuit is shown to provide a 90-percent improvement over the two conventional circuits in energy transferred to the uncoupled load. A low-current low-voltage experiment, where 35.4 percent of the initial inductive energy is transferred to an uncoupled load using the new circuit, is discussed. A physical design for the Air Force Weapons Laboratory Shiva bank, which accounts for voltage holding, coupling, and parasitic inductance in the switches, is also described.

A Meatgrinder circuit for energizing resistive and varying inductive loads (EM guns)

Inductive storage and transfer circuits energizing resistive or varying inductive loads at constant current are highly inefficient. These circuits suffer from current decay in the load or a substantial amount of energy left in the storage inductor. Previously, physical Meatgrinder circuit embodiments have been shown to provide highly efficient inductive energy storage and transfer to inductive loads, Recently, new Meatgrinder circuits have been synthesized to transfer energy to resistive and varying inductive loads at constant current and high efficiency. This paper describes and analyzes a physical embodiment which transfers 200 MJ at a constant current of 1.25 MA to an EM gun of varying inductance. The energy transfer efficiency to the accelerator is 44%.