ECE631/EE631Q Lecture 16: Average Value Model

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# ECE631/EE631Q Lecture 16: Average Value Model - PowerPoint PPT Presentation

## ECE631/EE631Q Lecture 16: Average Value Model

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##### Presentation Transcript

1. ECE631/EE631QLecture 16: Average Value Model S.D.Sudhoff Purdue University EE631 – Spring 2005

2. IM Overview EE631 – Spring 2005

3. Objectives For Today • Develop an Average Value Model for the 3-Phase Bridge Inverter • Features • Include conduction losses • Ignore switching losses EE631 – Spring 2005

4. Semiconductor Model • Transistor • Diode EE631 – Spring 2005

5. AVM – DC Currrent • Consider the current reference frame EE631 – Spring 2005

6. AVM – DC Current • Sine-Triangle Modulation with 3rd Harmonic EE631 – Spring 2005

7. AVM – DC Current • We have EE631 – Spring 2005

8. AVM – DC Current • We have EE631 – Spring 2005

9. AVM – DC Current EE631 – Spring 2005

10. AVM – DC Current • Thus we have for the a-phase • The total dc current must be given by EE631 – Spring 2005

11. AVM - Voltage • The fast average voltages may be expressed EE631 – Spring 2005

12. AVM - Voltage • The fundamental component of the line-to-ground voltage may be expressed EE631 – Spring 2005

13. AVM - Voltage • After substantial manipulation EE631 – Spring 2005

14. AVM - Voltage • After a little more work, we have • To show this EE631 – Spring 2005

15. AVM - Voltage EE631 – Spring 2005

16. AVM – Modulation Signal • Problem: we need to know d, d3, f • Starting point: modulation indices EE631 – Spring 2005

17. AVM – Modulation Signal • We will need the modulation signal in the current reference frame EE631 – Spring 2005

18. AVM – Modulation Signal • It can be shown that • To show this EE631 – Spring 2005

19. AVM – Modulation Signal EE631 – Spring 2005

20. AVM – Modulation Signal EE631 – Spring 2005

21. AVM – Modulation Signal • Lets also define a voltage reference frame • In this frame EE631 – Spring 2005

22. AVM – Modulation Signal • To show this EE631 – Spring 2005

23. AVM – Modulation Signal • Since we have • We therefore have EE631 – Spring 2005

24. AVM Modulation Signal • Desired magnitudes • For unsaturated operation EE631 – Spring 2005

25. AVM - Modulation • Analysis plan for saturated operation EE631 – Spring 2005

26. AVM Modulation • Results EE631 – Spring 2005

27. AVM Modulation • A subtle point • This occurs when EE631 – Spring 2005

28. AVM – Hysteresis Modulator EE631 – Spring 2005