Saber Circuit Simulator Research Articles

Analytical model for the double-gate JFET applied to SiC power JFETs

ABSTRACT An analytical and physical model for the double-gate vertical JFET (VJFET) with a lateral and a vertical channels is presented. The model has been implemented and tested in the SABER circuit simulator and its modeling language, MAST. The model includes an asymmetric representation of the lateral channel which is the main contribution of the paper. The blocking condition depends on both gate voltages. It is a key issue of the VJFET model and it is presented in details. Each junction of the structure is represented as a Shockley pn-junction model in parallel with the associated junction capacitance. The comparison between simulations and experiments yields to satisfying results, both in static and dynamic conditions. The analysis of the remaining difficulties to be solved is given.

Exponential ADE Solution Based Compact Model of Planar Injection Enhanced IGBT Dedicated to Robust Power Converter Design

The compact model of an injection enhanced insulated gate bipolar transistors based on the exponential solution of the ambipolar diffusion equation is presented in this paper. To model plasma carrier distribution, an exponential shape function is used, and in steady-state forward bias operation, the plasma carrier concentration has a distribution of catenary form with just two exponential basis functions, while in transient operation, more complex profiles can be approximated using a number of exponential basis functions with a range of decay length parameters, shorter than the steady state ones. The device model developed has been implemented in Saber circuit simulator and successfully tested against complete set of high current, high voltage experimental results.

Proposal for scalable models in EMC simulation

Abstract. In this paper a method "Component Series Modeling" (CoSeMod) is presented. This allows fast and easy implementation of scalable model generations for passive component series based on measurement data or specification provided by manufacturer. These can be used in circuit models for fast EMC analysis and optimization, especially in frequency ranges where conducted emission and susceptibility dominate. EMC tasks require high precision equivalent circuit models of components. Models generated with CoSeMod provide in many cases as high a quality as original (static) models do. One feature of scalability is that new netlisting is not needed after component changes. The process of model creation is based on similarities of the components of the same model series (packaging, manufacturing process, material etcetera). Required equations of the relationship between nominal and parasitic values are calculated by nonlinear regression. Model generation for unknown components of a known series is possible with interpolation. Implementation is possible with relatively simple actions made in circuit simulator Saber. An EMC application example of the implemented model is also shown in this paper.

SABER-Based Simulation for Compact Dynamic Electro-Thermal Modeling Analysis of Power Electronic Devices

Power electronic modules including insulated gate bipolar transistor (IGBT) are widely used in the field of power converter application. The temperature distribution inside these modules becomes more important for electrical characteristics, reliability and lifetime of integrated power electronic modules. In this paper, a seven-layer compact RC thermal component network model based on the physical structure is presented. A dynamic electro-thermal model, which is composed of electrical model, compact RC thermal component network model and electro-thermal interface is developed for the IGBT. These models interact with each other to calculate the temperature of each layer of module and parameters of each model. The thermal model determines the evolution of the temperature distribution within the thermal network and thus determines the instantaneous junction temperature used by the electrical model. Such built dynamic electro-thermal simulation methodology is implemented in the Saber circuit simulator, and the simulation result is validated by the experimental study, which adopted with infrared thermal imaging camera. The built dynamic electro-thermal model could be helpful for the research on operation performance and heat sink design for such power electronic devices.

Unified analytical model of HEMTs for analogue and digital applications

A unified model for the I–V characteristics of HEMTs valid for the subthreshold, linear and saturation regions of operation is presented. There is a smooth transition in the current from subthreshold to above threshold and also from linear to saturation. This results in highly continuous channel conductance (gds) and transconductance (gm), which are important circuit parameters in small signal analysis. Comparisons with experimental data show that the model is accurate and valid over a wide range. Further, it is established that the model holds good promise for analogue circuit design by subjecting it to a few benchmark tests. In addition, the model, which was originally developed for n-channel HEMTs, has been suitably modified to predict the I–V characteristics of p-channel HEMTs as well. Finally, an inverter circuit using p-channel HEMT as load and n-channel HEMT as driver has been successfully simulated using the circuit simulator SABER and the nature of the inverter characteristics are found to agree well with the experimental results.

Silicon carbide PiN and merged PiN Schottky power diode models implemented in the Saber circuit simulator

Dynamic electrothermal circuit simulator models are developed for silicon carbide power diodes. The models accurately describe the temperature dependence of on-state characteristics and reverse-recovery switching waveforms. The models are verified for the temperature dependence of the on-state characteristics, and the di/dt, dv/dt, and temperature dependence of the reverse-recovery characteristics. The model results are presented for 1500 V SiC Merged PiN Schottky (MPS) diodes, 600 V Schottky diodes, and 5000 V SiC PiN diodes. The devices studied have current ratings from 0.25 A to 5 A and have different lifetimes resulting in different switching energy versus on-state voltage trade-offs. The devices are characterized using a previously reported test system specifically designed to emulate a wide range of application conditions by independently controlling the applied diode voltage, forward diode current, di/dt, and dv/dt at turn-off. A behavioral model of the test system is implemented to simulate and validate the models. The models are validated for a wide range of application conditions for which the diode could be used.

Investigation of the power dissipation during IGBT turn-off using a new physics-based IGBT compact model

New compact models of the IGBTs (both non-punch through IGBT (NPTIGBT) and punch-through IGBT (PTIGBT)) are presented in this paper. The models are implemented in the SABER circuit simulator and used for a study of IGBT anode current and voltage characteristics during a device turn-off (clamped inductive load circuit with gate controlled turn-off), since these parts of the transient characteristics essentially predict the power dissipation ( V× I) inside the device. It is shown that PTIGBTs are faster than NPTIGBTs, this becoming more apparent at higher clamp voltages.

A single-reset-integrator-based implementation of line-current-shaping controller for high-power-factor operation of flyback rectifier

The objective of this paper is to present a simple yet accurate implementation of a resistor-emulator-type line-current-shaping controller for high-power-factor operation of a flyback rectifier. The important feature is that input voltage sensing is not required. In the circuit realization of the controller, no multiplier is used. Current shaping is performed directly on the input filter inductor current. The modulator uses only one reset integrator for the generation of duty ratio. The analysis presented in this paper shows the effect of input filter capacitance on discontinuous conduction mode of operation of the flyback inductor. Design equations for selection of the input filter components are derived. A low-frequency small-signal model of the rectifier is developed and verified by measurement up to 1 kHz. The performance of the controller is first tested by the SABER circuit simulator package. Then, a 100-W 110-V AC input 50-V DC output single-phase flyback rectifier prototype is built for experimental verification.

Dynamic Modeling of SRM Including Neighboring Phase Coupling Effects

This paper reports a new dynamic modeling method for switched reluctance motor (SRM) which can account for neighboring phase coupling effects. The dynamic model is developed using a few sets of finite element method (FEM)-computed phase flux linkage/current/position data under the condition of simultaneous excitation of two neighboring phases. The combination of piecewise Hermite cubic spline and Fourier series techniques is used to represent each FEM-calculated flux linkage data set. The methods to implement and to verify the dynamic model using simulation techniques are presented. The model is ready to be incorporated with various converter topologies and control strategies. It can provide valuable information for motor design evaluation and its controller design evaluation. The modeling method has been implemented using Saber circuit simulator for a 4-phase SRM driven by a split DC-link inverter. Dynamic simulation results have been obtained for two different SRM winding configurations. The significance of its neighboring phase coupling effects is evaluated by comparing the simulation results of a model including the effects with the simulation results of a degraded model neglecting the effects.

A fully-numerical model for PiN diodes implemented in the Saber circuit simulator

The integration of a full 1D numerical model for a power diode, into a commercial circuit simulator (Saber) is demonstrated for the first time. The model is based upon the solution of the full set of device equations making very few simplifications, thus retaining all the key elements of the physical operation of the device, and as such is therefore valid under all operating conditions. The model is verified against experimental measurements and full 2D numerical simulations of the device. The method used here can also be applied to model other power devices, which exhibit charge storage effects such as thyristors and IGBTs.

An experimentally verified hybrid Cassie-Mayr electric arc model for power electronics simulations

This paper presents an electric arc model that can approximately represent both the static and dynamic characteristics of an arc load controlled by a power electronic circuit. The proposed model was developed from the combination and modifications of the classical Cassie and Mayr equations. The model equations have been expressed in a form suitable for incorporation into circuit simulators employing the nodal analysis method of equation solving. The model has been test-implemented in the Saber circuit simulator. Simulated and experimental results appear to be in good agreement.

Application of field-based circuits to the modeling of magnetic components with hysteresis

A magnetic component with hysteresis is modeled as a network of field-based elemental subcircuits, whose currents and voltages are related to the dynamic electromagnetic fields in the component and an interface network, which couples the terminal voltages and currents to the field-based network. Such a model captures rate-dependent hysteresis, geometry, frequency and waveshape effects. Coupled transient simulation of the electromagnetic fields inside the core and circuit phenomena has been demonstrated using the Saber circuit simulator. The low-frequency inductances and hysteresis-related waveforms predicted by the model have been verified experimentally.

Electrothermal simulation of an IGBT PWM inverter

A recently developed electro-thermal network simulation methodology is used to analyze the behavior of a full-bridge, pulse-width-modulated (PWM), voltage-source inverter which uses insulated gate bipolar transistors (IGBTs) as the switching devices. The electro-thermal simulations are performed using the Saber circuit simulator and include the control logic circuitry, the IGBT gate drivers, the physics-based IGBT electro-thermal model, and the thermal network component models for the power device silicon chips, packages, and heat sinks. It is shown that the thermal response of the silicon chip determines the IGBT temperature rise during the device switching cycle. The thermal response of the device TO247 package and silicon chip determines the device temperature rise during a single phase of the 60-Hz sinusoidal output. Also, the thermal response of the heat sink determines the device temperature rise during the system start-up and after load impedance changes. It is also shown that the full electro-thermal analysis is required to accurately describe the power losses and circuit efficiency. >

One-dimensional analytical modeling of the VDMOS transistor taking into account the thermoelectrical interactions

An analytical one-dimensional thermoelectrical model for the power MOSFET transistor (VDMOS transistor) has been developed and implemented in the Saber circuit simulator. The device temperature becomes an interactive variable during the simulation. The model results in the combination of the electrical model of the device with a thermal network which models the different material layers crossed by the heat flow from the silicon chip to the heatsink (conduction phenomenon), and also takes into account the radiation and convection phenomena. The accuracy of the model is evaluated with electrical and thermal characterizations, and with a validation circuit.

A compact-charge LDD-MOSFET model

A compact-charge LDD-MOSFET model, based on an analytical surface potential formulation at source and drain has been derived and implemented in the circuit simulator SABER for all channel length and width down to deep submicrometer. Besides well-known short- and narrow-channel effects, the model includes additional charge effects around the threshold voltage as well as a bias dependent charge description of the overlap LDD(S)-region. These additional capacitance effects are not considered in conventional submicrometer transistor models although they domain the capacitance characteristic with further downscaling. If not taken into account, simulation errors of, e.g., up to 50% in the frequency of a 0.3 /spl mu/m CMOS ring oscillator or over 100% in the 3 dB critical frequency of amplifier circuits can result.

Dynamic electric arc model for electronic circuitsimulation

The authors present a physics based electric arc model which can simulate both static and dynamic characteristics of an arc load controlled by an electronic circuit. The proposed model was developed from modifications of the classical Cassie and Mayr equations. It has been test implemented in the Saber circuit simulator. There has been a considerable degree of correspondence between the simulated and experimental results.

Computer Simulation of a Radio Frequency Industrial System

A circuit model of a class C radio frequency industrial system has been developed. A novel method based on non-linear optimization is used to determine the tank circuit parameters together with its mutual coupling to the applicator. A model is also derived for the triode valve using the manufacturer’s data. The actual parameters of a 13.56 MHz radio frequency system are measured and used in the electrical model in order to enable their comparison. The model is then analyzed in the time-domain using the Saber circuit simulator. The results obtained from the model show good agreement with experiments.

A rational formulation of thermal circuit models for electrothermal simulation. II. Model reduction techniques [power electronic systems

For pt. I see ibid., vol. 43, no. 9, p. 721-32 (1996). To increase the efficiency of the electrothermal simulation of power electronic circuits and devices, model reduction techniques are applied to develop reduced thermal circuit models of Si chips, thermal packages, and heat sinks. Both the Modal Superposition method and a Component Mode Synthesis method are presented together with a model error estimation and a Ritz vector method. An alternative method for substructuring is also included. The reduced thermal circuit models are verified and implemented in the SABER circuit simulator. The electrothermal model of a full-bridge converter is simulated employing the proposed approach, and the results discussed.

Modeling buffer layer IGBTs for circuit simulation

The dynamic behavior of commercially available buffer layer insulated gate bipolar transistors (IGBTs) is described. It is shown that buffer layer IGBTs become much faster at high voltages than nonbuffer layer IGBTs with similar low voltage characteristics. Because the fall times specified in manufacturers' data sheets do not reflect the voltage dependence of switching speed, a new method of selecting devices for different circuit applications is suggested. A buffer layer IGBT model is developed and implemented into the Saber circuit simulator, and a procedure is developed to extract the model parameters for buffer layer IGBTs. It is shown that the new buffer layer IGBT model can be used to describe the dynamic behavior and power dissipation of buffer layer IGBTs in user-defined application circuits. The results of the buffer layer IGBT model are verified using commercially available IGBTs. >

An experimentally verified IGBT model implemented in the Saber circuit simulator

A physics-based insulated gate bipolar transistor (IGBT) model is implemented in the general-purpose circuit simulator Saber. The IGBT model includes all of the physical effects that have been shown to be important for describing IGBTs, and the model is valid for general external circuit conditions. The Saber IGBT model is evaluated for the range of static and dynamic conditions in which the device is intended to be operated, and the simulations compare well with experimental results for all of the conditions studied. >