Condition Monitoring for Power Electronics Reliability (COMPERE) 1 Condition Monitoring for Power Electronics Reliability (COMPERE) Shaoyong Yang Angus Bryant Phil Mawby Nov 3rd 2008

Contents Work plan – where we are and tasks. Back-to-back test rig. 1 Contents Work plan – where we are and tasks. Back-to-back test rig. 3. Review paper Discussion and Conclusion 4. Conference next year EPE, ECCE, ISIE 2

1 1. Original Work plan Power Converter Modelling Modified work plan 3

1 Modified work plan 4

LUT packaging damage Or spectral information Vge shift… 5 ΔT Tm 1 LUT packaging damage ΔT Tm Or spectral information Vge shift… ΔVCEsat ΔRth ΔVCEsat ΔRth Δt ΔRth ΔVCEsat 5

1 Modified work plan 6

Power Device Model –50°C ~ +150°C, Voltage & current. Compact models for IGBTs and diodes: Ambipolar diffusion equation describes carrier distribution. Proven over wide range conditions: –50°C ~ +150°C, Voltage & current. Have to be tailored/parameterised: On-state Switching behaviour (the right figure); 7

Tests for parameterisation 1 Tests for parameterisation SKM75GB123D 1200 V, 75 A 8

Matching for inductive switching 1 Matching for inductive switching Inductive switching shown here. IGBT turn-on (left), IGBT turn-off (right). Instantaneous power dissipations shown to validate switching energies. 9

Matching for on-state characteristics 1 Matching for on-state characteristics 10

1 Look-up table IGBT power losses (W) for whole switching cycle plotted as a function of load current (A), duty ratio and temperature (°C). 11

Power Converter Modelling 1 Power Converter Modelling IGBT model used in full converter modelling Simulation of every switching event is too time-consuming. Look-up table of losses is used instead: Generated from device models in MATLAB/Simulink. Gives losses as a function of load current and temperature. Simple converter/heatsink model then simulates device temperature. Rapid and accurate estimation of device temperature for whole load cycle. Converter simulation Look-up table Simulation controller EXTERNAL CONDITIONS LOSS DATA Device temp. Power diss. Heatsink model Compact models System modelling Device modelling 12

Progress for parameterisation 1 Progress for parameterisation 1 Switching and on-state tests have been carried out. 2 Full parameterisation of the selected Semikron module is expected in 2-4 weeks. 13

1 2.B2B test rig Designed to work at Vdc=450 V 14

1 B2B test rig 15

1 B2B test rig 16

Gate circuit Space vector width modulation+ PID control. 1 Gate circuit Space vector width modulation+ PID control. DC 100 V, 10 A tested. Gate outputs Gate drivers Signal+power inputs buffer 17

3. Review paper 1 Title – Peter’s suggestion Condition monitoring for reliability in power electronics converters – a review? 2 Discussion and conclusions Many thought it is not specific and deep enough. 18

Discussion part (1) 3D FEM Pros: investigate stress effect on bond-wire and solder layer. Cons: does not directly give predict reliability. Not feasible for drive cycle modelling. Thermal electrical (TE) Pros: feasible for drive cycle modelling, and gives temperature information. Thermal-mechanical (TM) Pros: gives reliability and predict lifetime- necessary for CM. Cons: complicated + interdisplinary. 3D FEM knowledge may be useful to learn thermal stress effect. TM should be built based on TE since the latter provide temp info. 19

Discussion part (2) Any suggestion for Table II? 1 Discussion part (2) Any suggestion for Table II? How to link power device part and CM techniques? 20

Conclusion CM will be emphasized, so the point (1) may be deleted. Main structure may be: Fault diagnosis useful… Modelling is an essential part… CM techniques… “Conclusion will need a re-write once the discussion has been sorted out”– Angus. I agree. 21

4. Conferences EPE 09: abstract deadline, 3 Nov 1 4. Conferences EPE 09: abstract deadline, 3 Nov ECCE 09: abstract deadline, Jan 15, 09 ISIE 09: Feb, 09 I will check again this part. 22

Thank you for your attention! 1 Thank you for your attention! 23