Condition Monitoring for Power Electronics Reliability (COMPERE)

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

2. 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

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

4. Modified work plan 4

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

6. Modified work plan 6

7. Power Device Model 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

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

9. 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

10. Matching for on-state characteristics 10

11. 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

12. 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 Simulation controller Look-uptable EXTERNAL CONDITIONS LOSS DATA Device temp. Power diss. Heatsink model Compact models System modelling Device modelling 12

13. 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

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

15. B2B test rig 15

16. B2B test rig 16

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

18. 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

19. 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. Cons: does not directly give predict reliability. • 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

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

21. 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

22. 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

23. Thank you for your attention! 23