Embedded Mechatronic Systems, Volume 2 (eBook)

Analysis of Failures, Modeling, Simulation and Optimization

Abdelkhalak El Hami, Philippe Pougnet (Herausgeber)

eBook Download: PDF | EPUB

2015 | 1. Auflage
272 Seiten
Elsevier Science (Verlag)
978-0-08-100469-2 (ISBN)

Infos

In operation, mechatronics embedded systems are stressed by loads of different causes: climate (temperature, humidity), vibration, electrical and electromagnetic. These stresses in components induce failure mechanisms should be identified and modeled for better control. AUDACE is a collaborative project of the cluster Mov'eo that address issues specific to mechatronic reliability embedded systems. AUDACE means analyzing the causes of failure of components of mechatronic systems onboard. The goal of the project is to optimize the design of mechatronic devices by reliability.

The project brings together public sector laboratories that have expertise in analysis and modeling of failure, major groups of mechatronics (Valeo and Thales) in the automotive and aerospace and small and medium enterprises that have skills in characterization and validation tests.

This book will help you to:

• Find and develop ways to characterize and validate the design robustness and reliability of complex mechatronic devices
• Develop ways to characterize physical and chemical phenomena,
• Identify mechanisms of failure of components of these devices,
• Analyze the physical and / or chemical mechanisms of failure, in order of importance
• To model failure mechanisms and design optimization.

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In operation, mechatronics embedded systems are stressed by loads of different causes: climate (temperature, humidity), vibration, electrical and electromagnetic. These stresses in components induce failure mechanisms should be identified and modeled for better control. AUDACE is a collaborative project of the cluster Mov'eo that address issues specific to mechatronic reliability embedded systems. AUDACE means analyzing the causes of failure of components of mechatronic systems onboard. The goal of the project is to optimize the design of mechatronic devices by reliability. The project brings together public sector laboratories that have expertise in analysis and modeling of failure, major groups of mechatronics (Valeo and Thales) in the automotive and aerospace and small and medium enterprises that have skills in characterization and validation tests. Find and develop ways to characterize and validate the design robustness and reliability of complex mechatronic devices Develop ways to characterize physical and chemical phenomena, Identify mechanisms of failure of components of these devices, Analyze the physical and / or chemical mechanisms of failure, in order of importance To model failure mechanisms and design optimization.

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2

Aging Power Transistors in Operational Conditions

Pascal Dherbecourt; Olivier Latry; Karine Dehais-Mourgues; Jean-Baptiste Fonder; Cédric Duperrier; Farid Temcamani; Hichame Maanane; Jean-Pierre Sipma

Abstract

This chapter describes how to perform power microwave transistors lifetime tests in operational conditions. The originality of this test bench is its ability to monitor automatically component performance during thousands of hours and to apply electrical and thermal stresses. This equipment is used to test high power transistors operating in pulsed mode and to record electrical parameter drifts using in-situ static and dynamic electrical characterization. The results of different aging processes of laterally diffused metal oxide semiconductor (LDMOS) high power transistors are presented

Keywords

Aging power transistors

Component under test (CUT)

Hot carrier injection (HCI)

In-situ principle

Laterally diffused metal oxide semiconductor (LDMOS)

LDMOS 330 W transistor

This chapter describes how to perform power microwave transistors lifetime tests in operational conditions. The originality of this test bench is its ability to monitor automatically component performance during thousands of hours and to apply electrical and thermal stresses. This equipment is used to test high power transistors operating in pulsed mode and to record electrical parameter drifts using in-situ static and dynamic electrical characterization. The results of different aging processes of laterally diffused metal oxide semiconductor (LDMOS) high power transistors are presented

2.1 Introduction

For radar system manufacturers equipment reliability is a major concern. Reliability is therefore taken into account in product design. Radar systems designers use electronic commercial components and must ensure good performance under specific operating conditions. During the product lifetime, power transistors will be required to function effectively in severe stress conditions (high or extremely low temperatures, very short pulse regime, high power, etc.). To ensure that the selected power components maintain a satisfactory level of performance throughout their life, aging tests are conducted respecting the operational conditions of the mission profile.

The test equipment presented in this chapter is used to study the reliability of microwave power transistors for the L frequency band for radar applications. This equipment is designed and built to provoke aging processes in power transistors due to operational pulsed mode use of radar systems [MAA 05]. It can apply stresses above the limits of the component specifications to accelerate the occurrence of failure. Failure mechanisms, however, must be identical to those caused by aging in real use conditions.

This chapter describes the design and the realization of the bench. The feasibility of in-situ characterization measurements of the component under test (CUT) is developed. Tests under operating radar conditions are conducted over 5,000 h. These tests confirm that the 300 W LDMOS power transistor meet the reliability requirements [LAT 10]. Test results in an overvoltage operation regime show that, after a relaxation period the CUT regains its original characteristics, demonstrating that the degradation phenomenon is not permanent [LAC 11]. Aging tests in a short pulse regime and in extreme cold conditions show that the electrical performance of the CUT is stable [DHE 14].

2.2 Aging microwave power electronic components under operational conditions

2.2.1 Definition of the specifications for the realization of the workbench

The aging behavior of the CUT depends on the operating conditions (voltage, current, power, etc.) and on the environmental conditions (temperature, humidity and vibrations). As the test equipment is designed and built to study the aging process of power transistors, the stresses that are applied reflect the operational conditions and the electrical and thermal parameters are recorded automatically. The equipment specifications are:

– an ability to test and monitor several components simultaneously, under operational conditions;

– 24-h operation;

– computer control (dedicated software);

– supply and precise control of the voltages and currents of the component;

– implementation and monitoring of environmental constraints (including temperature);

– secure storage of measurement data for performance indicators over several thousand hours;

– an ability to impose specific constraints on the radiofrequency component (e.g. introduction of an impedance mismatch or (voltage standing wave ratio (VSWR)), overvoltage, etc.);

– radiofrequency characterization of the components before and after aging;

– equipment integration and reasonable dimension.

The workbench records the suitable electrical parameters of the behavior of the power transistor in real operation conditions. It contributes to the improvement of the reliability of the transistors of different technologies, such as GaN High-electron-mobility transistor (HEMT) technology and LDMOS high power.

Concomitantly with the aging stresses, static current-voltage characteristics (I-V) using pulsed S-parameters are recorded [MAA 05]. The bench has four sub-units. Each sub-unit is equipped with a device to connect the component to be aged. Temperature and component supply voltages are fixed. In order to meet the requirements of the operational reliability study of microwave power transistors, several criteria are taken into account:

– expansion and adaptation over a wide range of power electric stress tests of the L frequency band;

– monitoring of the characteristics of the components (static I-V and dynamic S-parameters in situ);

– implementation of the extreme cold start and stop condition tests (a need to cool to −40°C in order to test the device under load with thermal cycling).

2.2.2 Applying stresses and measuring aging process parameters

The test equipment is designed for high-power microwave transistors that supply 30 A radiofrequency (RF) pulses. The equipment measures static current-voltage characteristics (I-V) in pulse mode and dynamic parameters (reflection coefficients and scattering matrix (S)) at different times without disconnecting the RF connections. The defects caused by aging are thus recorded and the measurement error is minimized. This in-situ principle ensures repeatable measurements and eliminates the offset due to the loss of calibration by attaching and removing connectors. Figure 2.1 shows the test bench architecture.

Figure 2.1 Schematic view of the workbench for aging and characterization. For a color version of the figure, see www.iste.co.uk/elhami/mechatronic2.zip

The heart of the system synchronizes all supply signals: gate voltage, drain voltage, input power level and soleplate temperature. Figure 2.2 provides a control timing for the GaN HEMT transistor.

Figure 2.2 Chronograms for the command of the workbench, drain and gate voltages Vds and Vgs. For a color version of the figure, see www.iste.co.uk/elhami/mechatronic2.zip

The control unit synchronizes the radiofrequency pulse generator and provides synchronization of the input and the output power measurements of the CUT. Measuring the reflected power denoted as (Pref) is achieved in continuous mode (CW). Each channel has an adjustable attenuator, a coupler for measuring the input power and a circulator for the reflected power of the CUT, measured into a matched load impedance. The amplification of the radiofrequency signal is provided by a two-stage amplifier (A and B amplifiers).

Measurement parameters during aging are driven by the heart of the system. This ensures the correct measurements of the currents and the voltages for drain and gate, the input and output powers, the reflected power, and the room temperature, the soleplate and dissipation radiators’ temperature. To characterize the aging of the device, 15 parameters are measured. Table 2.1 shows all of these parameters.

Table 2.1

Physical parameters recorded by the workbench

Electrical supply

Drain supply

Vds

High level

0 V

60 V

Low level

Ids

High level

80 mA

4 A

Low level

Gate supply

Vgs

High level

−15 V

+15 V

Low level

Igs

High...

Produkt-Details

• Erscheint lt. Verlag: 16.7.2015
• Sprache: englisch
• Themenwelt: Technik ► Bauwesen
• Themenwelt: Technik ► Elektrotechnik / Energietechnik
• Themenwelt: Technik ► Maschinenbau
• Themenwelt: Technik ► Nachrichtentechnik
• ISBN-10: 0-08-100469-9 / 0081004699
• ISBN-13: 978-0-08-100469-2 / 9780081004692