Voltage Control of SinglePhase Inverters Commonlyused Techniques SinglePulseWidthModulation
- Slides: 17
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 ECE 442 Power Electronics 1
Single-Pulse-Width-Modulation ECE 442 Power Electronics 2
One Pulse per Half-Cycle Pulse Width Controls the Output Voltage ECE 442 Power Electronics 3
Carrier and Reference Signals Gate Pulse • Compare the Reference Signal with the Carrier • Frequency of the Reference Signal determines the frequency of the Output Voltage • Modulation Index = M = Ar/Ac ECE 442 Power Electronics 4
Gate Signals and Output ECE 442 Power Electronics 5
rms value of the Output Voltage ECE 442 Power Electronics 6
Fourier Series for the Output Voltage ECE 442 Power Electronics 7
Times and angles of the intersections Pulse width d (or pulse angle δ) ECE 442 Power Electronics TS = T/2 8
Harmonic Profile ECE 442 Power Electronics 9
Multiple-Pulse-Width-Modulation ECE 442 Power Electronics 10
Multiple Pulses per Half-Cycle of Output Voltage ECE 442 Power Electronics 11
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 ECE 442 Power Electronics 12
Gate Signals and Output Voltage Number of pulses per half cycle = p = fc/2 fo = mf /2 where mf = frequency modulation ratio ECE 442 Power Electronics 13
rms Value of the Output Voltage ECE 442 Power Electronics 14
Fourier Series of the Output Voltage ECE 442 Power Electronics 15
The times and angles of the intersections The pulse width d (or pulse angle δ) ECE 442 Power Electronics TS = T/2 p 16
Harmonic Profile ECE 442 Power Electronics 17
