I am reading the paper "Analysis of Dual-Carrier Modulator for Bidirectional Noninverting Buck–Boost Converter" by Ilan Aharon et al and one question comes up.
As you can see from the attached picture, a symmetrical triangle waveform is used as modulation signal in the paper.
So is there any reason for using triangle waveform rather than sawtooth or ramp for modulation? Or what are the advantages or disadvantages of each one?
For duty cycle, I don't see any difference among these modulation signal. They all works in theory but I am not sure the side effect of each type.
Link to the paper: Article Analysis of Dual-Carrier Modulator for Bidirectional Noninve...
yes there will be different in the switching pattern and the pulses time also. The saw tooth is applicable for certain inverter applications. The issue maybe related to the switching losses.
Dear Huan,
any waveform that is a triangle in nature can be used for pulse generation.
Depending on the shape, the main differences are:
1) saw tooth always has turn-off or falling edge at the end of the period
2) ramp has turn-on or rising edge at the beginning of the period
3) symmetric triangle is always off at the beginning and the end of the period.
This behaviour translates into slight differences in Fourier Analysis and thus has an influence to filter design.
Typically, EMI can best be handled using a symmetric triangle.
Pulse Width Modulation (PWM) is a modulation method that uses any of wave forms you mentioned in your question (all could be used according to the specific PWM method and application).
The carrier waveform (sine) is compared with symmetric triangle to have PWM control method that will produce output voltage with low ripple . While if compared with saw-tooth or ramp the ripple will be much more.
Hope it helps!
Article Design of PWM Ramp Signal in Voltage-Mode CCM Random Switchi...
- Badges
- Science topic