On-board health monitoring of power modules in inverters driving induction motors

This thesis presents an on-board methodology for monitoring the health of power (converter) modules in drive systems. The ability to keep regular track of the actual degradation level of the modules enables the adoption of preventive maintenance, reducing or even eliminating altogether the appearance of failures during operation, significantly improving the availability of the power devices. The novelty of this work is twofold: the complete system that is used to achieve degradation monitoring; combining the heating technique (to obtain thermal transient) and the measurement without additional power components such as IGBT, MOSFETS, which affects the reliability, power density and complexity. The only additional component is an analog measurement circuit, which can be integrated into the gate drive board. The test routine is carried out during non-operational periods and idle times. Trains are used as a case study, where checks for degradation are made when the train is not in use, such as at the end of the day, after daily operation or at the start before daily operation and other non-operational periods. It is important to keep the train at standstill while tests are carried out. Hence a methodology to heat the devices with current from the input supply while keeping the motor load at a stand-still is presented. Experimental results obtained from this show that it is possible to implement an on-board health monitoring system in converters which measures the degradation on power modules. The work uses the concepts of vector control heating and structure function to check for degradation. It puts forward a system that is used on-board to measure the cooling curve and derive the structure function during idle times for maintenance purposes. The structure function is good tool for tracking the magnitude and location of degradation in power modules. Vector control gives the advantage of controlling the motor with field current and torque current (similar concept to DC motors)

On-board health monitoring of power modules in inverters driving induction motors

This thesis presents an on-board methodology for monitoring the health of power (converter) modules in drive systems. The ability to keep regular track of the actual degradation level of the modules enables the adoption of preventive maintenance, reducing or even eliminating altogether the appearance of failures during operation, significantly improving the availability of the power devices. The novelty of this work is twofold: the complete system that is used to achieve degradation monitoring; combining the heating technique (to obtain thermal transient) and the measurement without additional power components such as IGBT, MOSFETS, which affects the reliability, power density and complexity. The only additional component is an analog measurement circuit, which can be integrated into the gate drive board. The test routine is carried out during non-operational periods and idle times. Trains are used as a case study, where checks for degradation are made when the train is not in use, such as at the end of the day, after daily operation or at the start before daily operation and other non-operational periods. It is important to keep the train at standstill while tests are carried out. Hence a methodology to heat the devices with current from the input supply while keeping the motor load at a stand-still is presented. Experimental results obtained from this show that it is possible to implement an on-board health monitoring system in converters which measures the degradation on power modules. The work uses the concepts of vector control heating and structure function to check for degradation. It puts forward a system that is used on-board to measure the cooling curve and derive the structure function during idle times for maintenance purposes. The structure function is good tool for tracking the magnitude and location of degradation in power modules. Vector control gives the advantage of controlling the motor with field current and torque current (similar concept to DC motors)

Prognostic System for Power Modules in Converter Systems Using Structure Function

This paper proposes an on-board methodology for monitoring the health of power converter modules in drive systems, using vector control heating and structure function to check for degradation. It puts forward a system that is used on-board to measure the cooling curve and derive the structure function during idle times for maintenance purposes. The structure function is good tool for tracking the magnitude and location of degradation in power modules. The ability to keep regular track of the actual degradation level of the modules enables the adoption of preventive maintenance, reducing or even eliminating altogether the appearance of failures during operation, significantly improving the availability of the power devices. The novelty in this work is the complete system that is used to achieve degradation monitoring; combining the heating technique and the measurement without additional power components except the measurement circuit which can be integrated into the gate drive board and the challenges encountered. Experimental results obtained from this show that it is possible to implement an on-board health monitoring system in converters which measures the degradation on power modules

Measuring structure functions of power devices in inverters

This paper proposes the measuring of structure function from power devices on-board induction motor drives and multilevel converters. It puts forward the issues and methodology related to on-board measurement of the cooling curve and derivation of the structure function during idle times in induction motor drives for maintenance purposes. The structure function uses the thermal resistances and capacitances in the Cauer form to identify changes in the device structure. The advantage of the structure function is that it does not only reveal the value but also the location of the thermal resistance and capacitance in the heat flow path. The novelty in this work is the methodology used to achieve the measurement of the cooling curve and obtaining the structure function despite issues related to freewheeling current due to energy stored as a result of motor inductance. A detailed description of the measurement circuit is presented. The possibility of applying this technique to multilevel converters in different application is also elaborated

Extracting structure functions of power devices in induction motor drives

This paper proposes the extraction of structure function from power devices on-board induction motor drives. It puts forward the issues and methodology related to on-board measurement of the cooling curve and derivation of the structure function during idle times in induction motor drives for maintenance purposes. The structure function uses the thermal resistances and capacitances in the Cauer form to identify changes in the device structure. The advantage of the structure function is that it does not only reveal the value but also the location of the thermal resistance and capacitance in the heat flow path. The novelty in this work is the methodology used to achieve the measurement of the cooling curve and the derivation of the structure function despite issues related to freewheeling current due to energy stored as a result of motor inductance

Modular integrated SiC MOSFET matrix converter

This paper presents the assembly and characterization of an integrated all SiC 3-to-1 phases matrix converter, of typical application in domains requiring harsh environment withstand capability with high reliability and availability levels (e.g., renewable energies, solid-state transformation, smart grids, electric transport). Commercially available silicon-carbide (SiC) power MOSFETs are procured in bare-die form to develop custom-packaged bi-directional switches, with an advanced approach aiming to optimize the electro-thermal and electro-magnetic performance at switch level. Advanced cooling and packaging solutions at system level enable modularity with reduced impact of single component failure on the overall system, contributing to significantly reduced maintenance and repair costs

言語習得における年齢要因に関する考察 : 認知的視点より

Pressure contact packages have demonstrated an improved reliability for silicon devices due to the elimination of the weak elements of the packaging, namely wirebonds and solder. This packaging approach has not yet been widely studied for SiC devices, however, it is of high interest for applications like HVDC or rail traction, where the wide bandgap properties of SiC devices can be fully exploited and high reliability is critical. Current IGBT press-pack modules use Si PiN diodes for enabling reverse conduction, however, the use of SiC Schottky diodes would be beneficial given their better characteristics including low switching losses and lower zero temperature coefficient (ZTC) for electrothermal stability of diodes in parallel. A prototype for the evaluation of SiC Schottky diodes using pressure contacts has been designed, built and tested for both single die and multiple die

Pressure contact multi-chip packaging of SiC Schottky diodes

Pressure contact packages have demonstrated an improved reliability for silicon devices due to the elimination of the weak elements of the packaging, namely wirebonds and solder. This packaging approach has not yet been widely studied for SiC devices, however, it is of high interest for applications like HVDC or rail traction, where the wide bandgap properties of SiC devices can be fully exploited and high reliability is critical. Current IGBT press-pack modules use Si PiN diodes for enabling reverse conduction, however, the use of SiC Schottky diodes would be beneficial given their better characteristics including low switching losses and lower zero temperature coefficient (ZTC) for electrothermal stability of diodes in parallel. A prototype for the evaluation of SiC Schottky diodes using pressure contacts has been designed, built and tested for both single die and multiple die

Co-design/simulation of flip-chip assembly for high voltage IGBT packages

This paper details a co-design and modelling methodology to optimise the flip-chip assembly parameters so that the overall package and system meets performance and reliability specifications for LED lighting applications. A co-design methodology is employed between device level modelling and package level modelling in order enhance the flow of information. As part of this methodology, coupled electrical, thermal and mechniacal predictions are made in order to mitigate underfill dielectric breakdown failure and solder interconnect fatigue failure. Five commercial underfills were selected for investigating the trade-off in materials properties that mitigate underfill electrical breakdown and solder joint fatigue