1. ECE 442 Power Electronics1 Voltage Control of Single-Phase Inverters Commonly-used Techniques –Single-Pulse-Width-Modulation –Multiple-Pulse-Width-Modulation –Sinusoidal-Pulse-Width-Modulation –Modified-Sinusoidal-Pulse-Width-Modulation –Phase-Displacement Control

2. ECE 442 Power Electronics2 Single-Pulse-Width-Modulation

3. ECE 442 Power Electronics3 One Pulse per Half-Cycle Pulse Width Controls the Output Voltage

4. ECE 442 Power Electronics4 Carrier and Reference Signals Compare the Reference Signal with the Carrier Frequency of the Reference Signal determines the frequency of the Output Voltage Modulation Index = M = A r /A c Gate Pulse

5. ECE 442 Power Electronics5 Gate Signals and Output

6. ECE 442 Power Electronics6 rms value of the Output Voltage

7. ECE 442 Power Electronics7 Fourier Series for the Output Voltage

8. ECE 442 Power Electronics8 Times and angles of the intersections Pulse width d (or pulse angle δ) T S = T/2

9. ECE 442 Power Electronics9 Harmonic Profile

10. ECE 442 Power Electronics10 Multiple-Pulse-Width-Modulation

11. ECE 442 Power Electronics11 Multiple Pulses per Half-Cycle of Output Voltage

12. ECE 442 Power Electronics12 Gate Signal Generation Compare the Reference Signal with the Carrier Frequency of the Reference Signal determines the Output Voltage Frequency Frequency of the Carrier determines the number of pulses per half-cycle Modulation Index controls the Output Voltage

13. ECE 442 Power Electronics13 Gate Signals and Output Voltage Number of pulses per half cycle = p = f c /2f o = m f /2 where m f = frequency modulation ratio

14. ECE 442 Power Electronics14 rms Value of the Output Voltage

15. ECE 442 Power Electronics15 Fourier Series of the Output Voltage

16. ECE 442 Power Electronics16 The times and angles of the intersections The pulse width d (or pulse angle δ)T S = T/2p

17. ECE 442 Power Electronics17 Harmonic Profile