Reduction of Output Voltage Ripples in Frequency Modulated Power Converter

Effects of Switching Frequency Modulation on Input Power Quality of Boost Power Factor Correction Converter

“…However the inductor is assumed to be linear. In order to take into account real power MOSFET and its control circuit (including PWM) turn-on switching delays (t don ) and turn-of switching delays (t doff ) (which in fact can have major influence on low-frequency content of switching-frequency modulated dc/dc power converetrs voltages [16], [19], [32]- [33]), turn-on and turn-off delay blocks consisting of two "Transport Delay" blocks, logic operators AND and OR are added to the model ( Figure 3). Using that blocks we can independently enter t don and t doff values.…”

“…[10] - [15]. In fact, the spread-spectrum technique has become very popular technique for SMPS EMI reduction in the scientific community owing to its good EMI reduction potential along with easiness of implementation and adding little or no additional cost to SMPS [12], [14], [16] - [19]. Spreading the spectrum of SMPS voltages and currents and EMI noise reduction ( Figure 1) can be achieved by modulating one of the pulse-width-modulated (PWM) control signal parameters such as the pulse position [20], duty ratio [21], or frequency [22].…”

“…Similarly to other EMI reduction techniques, SFM also has some disadvantages: it can increase output voltage and input current ripples of SMPS, as well as worsen the PQ of PFC converters and resonant inverters for induction heating appliances [16], [19], [22]- [28]. Figure 1.…”

Hybrid-modulation-based control technique for reduction of output voltage ripples in frequency-modulated switch-mode power converters

“…However the main problem with the use of this technique in conventional DC/DC or AC/DC SMPC is that peak-to-peak output voltage and power stage peak currents (e.g. power inductor or power MOSFET currents) can increase significantly [13] - [16]. Increase in peak-to-peak output voltage of SMPC can be very harmful to electronic equipment powered by the SMPC, but increase in peak currents of power magnetic components can lead to increase in losses and even to saturation of a magnetic core of transformers or inductors.…”

“…In [13] - [17] the effect of SFM on peak-to-peak output voltage and power stage peak currents of DC/DC SMPC operating in continuous conduction mode (CCM) and discontinuous conduction mode (DCM) was studied in details and some recommendations for proper design of DC/DC SMPC were proposed. However, the recommendations are not sufficiently useful to get low peak-to-peak output voltage and power stage peak currents, especially for switching-frequency-modulated SMPC operating in DCM.…”