Chapter 8 SwitchMode DCAC Inverters converters for ac

Chapter 8 Switch-Mode DC-AC Inverters • converters for ac motor drives and uninterruptible power supplies 8 -1

Switch-Mode DC-AC Inverter Power flow • Block diagram of a motor drive where the power flow is unidirectional 8 -2

Switch-Mode DC-AC Inverter Power flow • Block diagram of a motor drive where the power flow can be bi-directional 8 -3

Switch-Mode DC-AC Inverter • Four quadrants of operation 8 -4

Full-Bridge DC-DC Converter 8 -5

Half-bridge DC-AC Inverter • Half-bridge inverter (One leg of full bridge converter) 8 -6

Square-Wave Mode of Operation • Harmonics are of the fundamental frequency 8 -7

Effect of Blanking Time • Results in nonlinearity 8 -8

Effect of Blanking Time • Effect on the output voltage 8 -9

Synthesis of a Sinusoidal Output by PWM 8 -10

Synthesis of a Sinusoidal Output by PWM (2) 1 8 -11

Half-Bridge DC-AC Inverter • Capacitors provide the mid-point 8 -12

Full-Bridge DC-AC Inverter 8 -13

Full-Bridge DC-AC Inverter Bipolar Voltage switching 8 -14

Full-Bridge DC-AC Inverter Unipolar Voltage Switching 8 -15

Full-Bridge DC-AC Inverter Unipolar Voltage Switching 1 • Harmonic components around the switching frequency are absent 8 -16

Sinusoidal Synthesis by Voltage Shift 8 -17

Programmed Harmonic Elimination • Angles based on the desired output • IC circuit or microcontroller required 8 -18

Summary of DC-AC Inverters PWM square-wave 8 -19