EE 8407 Power Converter Systems Topic 4 Graduate

EE 8407 Power Converter Systems Topic 4 Graduate Course EE 8407 Bin Wu Ph. D, PEng Professor ELCE Department Ryerson University Contact Info Office: ENG 328 Tel: (416) 979 -5000 ext: 6484 Email: bwu@ee. ryerson. ca http: //www. ee. ryerson. ca/~bwu/ Ryerson Campus Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 1

EE 8407 Topic 4 Multi-pulse SCR Rectifiers Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 2

EE 8407 Multi-pulse SCR Rectifiers Topic 4 Lecture Topics • Six-pulse SCR Rectifier (Building Block) • 12 -, 18 - and 24 -pulse SCR Rectifiers • THD and PF Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 3

EE 8407 Multi-pulse SCR Rectifiers Topic 4 Why Use Multi-pulse SCR Rectifiers? • To reduce line THD • To improve input power factor • To avoid semiconductor devices in series. Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 4

EE 8407 Six-pulse SCR Rectifier Topic 4 • Converter Configuration • Assumption: 1) Ideal SCRs - no power loss 2) dc current ripple free • Use constant current source Id as a load Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 5

EE 8407 Six-pulse SCR Rectifier Topic 4 • Waveforms • Average dc voltage Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 6

EE 8407 Six-pulse SCR Rectifier Topic 4 • Fourier Analysis • RMS current • THD Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 7

EE 8407 Six-pulse SCR Rectifier Topic 4 • Power Factor (PF) • Displacement Power Factor • Overall Power Factor Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 8

EE 8407 Six-pulse SCR Rectifier Topic 4 • Waveforms at Various Firing Angles Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 9

EE 8407 Six-pulse SCR Rectifier Topic 4 • Effect of Line Inductance Ls Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 10

EE 8407 Six-pulse SCR Rectifier Topic 4 • Waveform During SCR Commutation Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 11

EE 8407 Six-pulse SCR Rectifier Topic 4 • DC Voltage Reduction (caused by commutation) • S 1 and S 5 on (during commutation) from which • Since ia + ic = Id, and id is constant from which Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 12

EE 8407 Six-pulse SCR Rectifier Topic 4 • DC Voltage Reduction • Shaded Area Aγ • Since • Average dc voltage loss • Average dc output voltage Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 13

EE 8407 Six-pulse SCR Rectifier Topic 4 • Commutation Interval • Aγ can be rearranged as where • Substitute into the above equation from which Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 14

EE 8407 Six-pulse SCR Rectifier Topic 4 • Line Current Waveforms Ls = 0. 05 pu Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 15

EE 8407 Six-pulse SCR Rectifier Topic 4 • Line Current THD Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 16

EE 8407 Six-pulse SCR Rectifier Topic 4 • Power Factor Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 17

EE 8407 12 -pulse SCR Rectifier Topic 4 • Topology • Main Benefits - Low line current THD - No SCRs in series Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 18

EE 8407 12 -pulse SCR Rectifier Topic 4 • Application Example • Used for current source inverter (CSI) fed drive Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 19

EE 8407 12 -pulse SCR Rectifier Topic 4 • Waveforms of Idealized Rectifier (Ls = Llk = 0) Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 20

EE 8407 12 -pulse SCR Rectifier Topic 4 • Fourier Analysis • Secondary currents Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 21

EE 8407 12 -pulse SCR Rectifier Topic 4 • Fourier Analysis (continued) • Secondary currents referred to the primary side • Primary line current Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 22

EE 8407 12 -pulse SCR Rectifier Topic 4 • Line Current THD • Secondary side • Primary side Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 23

EE 8407 12 -pulse SCR Rectifier Topic 4 • Line Current Waveform (Ls 0 ) Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 24

EE 8407 12 -pulse SCR Rectifier Topic 4 • THD and PF Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 25

EE 8407 18 -pulse SCR Rectifier Topic 4 • Rectifier Configuration Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 26

EE 8407 18 -pulse SCR Rectifier Topic 4 • Waveforms Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 27

EE 8407 18 -pulse SCR Rectifier Topic 4 • Line Current THD Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 28

EE 8407 24 -pulse SCR Rectifier Topic 4 • Rectifier Configuration Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 29

EE 8407 24 -pulse SCR Rectifier Topic 4 • Line Current THD Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 30

EE 8407 Topic 4 Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006 31