Characteristics Of Power Module Research Articles

Adaptive Stray Inductance Extraction Algorithm Using Linear Regression for Power Module With High Noise Immunity and Accuracy

Stray inductance has great impacts on characteristics of power module and how to extract the inductance accurately is a significant challenge to guide the layout design and application of power module. The inductance during rapid gradient of current poses threaten to power module so the suitable stages for inductance extraction are recommended on account of dynamic characteristics. The existing method extracts inductance by two measure points and accuracy is low, which is influenced by measurement error significantly, so this paper proposes an adaptive stray inductance extraction algorithm, the essence of which is the least square method. The proposed algorithm applies least square method to extract stray inductance by fitting numerous sample points by double pulse test and eliminates the influence of measurement error because the residual obeys normal distribution same with measurement error. As a result, the proposed algorithm is with high noise immunity and accuracy. Finally, a multichips IGBT power module is tested under various conditions to verify the effectiveness of proposed method. Consequently, the error of extracted inductance is less than 5% and consistency is great.

Modeling of Power Module for 48 V High Power Inverter

The paper presents simulation and measurement results of high current three-phase inverter power modules used in 48V motor application. Firstly, FEM (Finite Element Method) is used to extract circuit parasitics. With the inclusion of MOSFET and passive component SPICE models, highly accurate simulation model is created. Switching characteristics of power module are simulated at 300 A load current and 48 V battery voltage. Thermal simulations estimate maximum transistor temperatures at given power losses. Electrical simulations are compared to actual measurements under identical test conditions. Comparison shows good matching between simulations and measurements. The phase voltage rise and fall times are the same in simulations and measurements. The overshoot voltages are also the same in both cases, around 28 V. The mismatch can be found in the currents of secondary loops. The gate voltage signal is similar with small mismatch of Miller plateau voltage, due to transistor model parameters mismatch.

Small and large signal analysis using circuit model of InGaAs/InP based uni-travel carrier photodiode

An equivalent circuit model of uni-traveling carrier photodiode (UTC-PD) is developed from integral carrier density rate equation and few important properties of the device such as the electrical and optical characteristics are evaluated by employing advanced device physics. Circuit model incorporates chip and package parasitic of the device quite simply to provide practical behaviour of UTC-PD. We have developed small signal ac circuit model which is useful for the analysis of low power modulation characteristics of the device and dc circuit model which is advantageous to find wavelength dependent responsivity fairly accurately. At high optical input power the device bandwidth is found to be increased through enhancement of self-induced field in the absorption region and high output power can be derived from the device when absorption width is large. Such condition calls for large signal analysis. We have developed large signal circuit model by combining few mathematical transformations with small signal circuit model with different circuit element values. Our large signal model is unique that the same circuit can be used for both small and large signal analysis. With large signal model the optical power induced bandwidth improvement and output photocurrent saturation are explained. Large signal model is validated through linearity and IP3 analysis which found close agreement with the measured results.

Suppressing Transient Shaft Stresses of Turbine-Generators using a Static Phase-Shifter

A novel approach for damping transient oscillatory stresses of the shaft segments of large steam turbine-generators, based on the application of static phase-shifters is presented. The supplementary damping is obtained based on the active power modulation characteristics of static phase-shifters, by injecting lead-lag quadrature phase voltage, using the rotor speed deviation from the synchronous speed as the control signal. A detailed digital simulation study, using the BPA's EMTP, is conducted to reveal the damping effect of static phase-shifters under different operating points, system configurations and switching time intervals. Emphasis is placed on the most severe disturbances, e.g., three-phase faults and automatic reclosures. The simulation results indicate that injection of 7% of the system phase voltage, in 4 discrete steps of 1.75%, can effectively reduce the peak torque and life-times of the shaft system oscillatory stresses.

Two-wavelength and power-balanced oscillation of a CO2 laser for application to differential absorption measurements

A new technique of alternate two-wavelength oscillation of a CO2 laser is discussed for application to various differential absorption spectroscopic measurements. Power-balanced, two-adjacent branch oscillation using a single CO2 laser was achieved by modulating the angle of a mirror inside the laser cavity and adjusting automatically the cavity length. The two-wavelength modulation frequency was extended up to about 1.2 kHz. Line tuning and power modulation characteristics were studied. The laser was used in long-path differential absorption measurements of ethylene air pollution molecules to demonstrate the capability of this power-balanced, two-wavelength oscillation method. The minimum detectable absorption was nearly 1×10−3 in a short-path cell experiment and 3×10−3 in a long-path experiment.