1. Switch-Mode DC-AC Inverters
Chapter 8
Switch-Mode DC-AC Inverters
converters for ac motor drives and uninterruptible power supplies
Copyright © 2008
by Jose Bastos
Chapter 8 Switch-Mode DC-
Sinusoidal AC Inverters

2. Switch-Mode DC-AC Inverter
Power flow
Block diagram of a motor drive where the power flow is unidirectional
Copyright © 2008
by Jose Bastos
Chapter 8 Switch-Mode DC-
Sinusoidal AC Inverters

3. Switch-Mode DC-AC Inverter
Power flow
Block diagram of a motor drive where the power flow can be bi-directional
Copyright © 2008
by Jose Bastos
Chapter 8 Switch-Mode DC-
Sinusoidal AC Inverters

4. Switch-Mode DC-AC Inverter
Four quadrants of operation
Copyright © 2008
by Jose Bastos
Chapter 8 Switch-Mode DC-
Sinusoidal AC Inverters

5. Full-Bridge DC-DC Converter
Copyright © 2008
by Jose Bastos
Chapter 8 Switch-Mode DC-
Sinusoidal AC Inverters

6. Half-bridge DC-AC Inverter
Half-bridge inverter
(One leg of full bridge converter)
Copyright © 2008
by Jose Bastos
Chapter 8 Switch-Mode DC-
Sinusoidal AC Inverters

7. Square-Wave Mode of Operation
Harmonics are of the fundamental frequency
Copyright © 2008
by Jose Bastos
Chapter 8 Switch-Mode DC-
Sinusoidal AC Inverters

8. Effect of Blanking Time
Results in nonlinearity
Copyright © 2008
by Jose Bastos
Chapter 8 Switch-Mode DC-
Sinusoidal AC Inverters

9. Effect of Blanking Time
Effect on the output voltage
Copyright © 2008
by Jose Bastos
Chapter 8 Switch-Mode DC-
Sinusoidal AC Inverters

10. Synthesis of a Sinusoidal Output by PWM
Copyright © 2008
by Jose Bastos
Chapter 8 Switch-Mode DC-
Sinusoidal AC Inverters

11. Synthesis of a Sinusoidal Output by PWM (2)1
Copyright © 2008
by Jose Bastos
Chapter 8 Switch-Mode DC-
Sinusoidal AC Inverters

12. Half-Bridge DC-AC Inverter
Capacitors provide the mid-point
Copyright © 2008
by Jose Bastos
Chapter 8 Switch-Mode DC-
Sinusoidal AC Inverters

13. Full-Bridge DC-AC Inverter
Copyright © 2008
by Jose Bastos
Chapter 8 Switch-Mode DC-
Sinusoidal AC Inverters

14. Full-Bridge DC-AC Inverter
Bipolar Voltage switching
Copyright © 2008
by Jose Bastos
Chapter 8 Switch-Mode DC-
Sinusoidal AC Inverters

15. Full-Bridge DC-AC Inverter Unipolar Voltage Switching
Copyright © 2008
by Jose Bastos
Chapter 8 Switch-Mode DC-
Sinusoidal AC Inverters

16. Full-Bridge DC-AC Inverter Unipolar Voltage Switching1
Harmonic components around the switching frequency are absent
Copyright © 2008
by Jose Bastos
Chapter 8 Switch-Mode DC-
Sinusoidal AC Inverters

17. Sinusoidal Synthesis by Voltage Shift
Copyright © 2008
by Jose Bastos
Chapter 8 Switch-Mode DC-
Sinusoidal AC Inverters

18. Programmed Harmonic Elimination
Angles based on the desired output
IC circuit or microcontroller required
Copyright © 2008
by Jose Bastos
Chapter 8 Switch-Mode DC-
Sinusoidal AC Inverters

19. Summary of DC-AC Inverters
PWM
square-wave
Copyright © 2008
by Jose Bastos
Chapter 8 Switch-Mode DC-
Sinusoidal AC Inverters