Modeling of load-transient response of direct-duty-ratio-controlled buck converter

To balance the cost and volume when applying a low output current ripple, the power supply design should be able to eliminate the current ripple under any duty cycle in medium and high switching frequencies, and considerably reduce filter volume to improve power density. A stacked buck converter was eventually selected after reviewing the existing solutions and discussing their advantages and disadvantages. A stacked buck converter is used as a basis to propose the transient response and output current ripple elimination effect, boundary limit control method, and low output ripple dead time modulation method to make individual improvements. The principle, mathematical derivation, small-signal model, and compensator design method of the improvement method are presented in detail. Moreover, simulation results are used to mutually verify the correctness and effectiveness of the improvement method. A stacked buck converter with 330-V input, 50-V output, and 1-kW output power was implemented to verify the effect of the low output current ripple dead time modulation. Experimental results showed that the peak-to-peak value of the output current ripple was reduced from 2.09 A to 559 mA, and the RMS value was reduced from 551 mA to 91 mA, thereby effectively improving the output current ripple.

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Compensated Single Input Multiple Output Flyback Converter

Energies ◽

10.3390/en14113009 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3009

Author(s):

Mohammad Tahan ◽

David O. Bamgboje ◽

Tingshu Hu

Keyword(s):

Transient Response ◽

Current Mode ◽

Voltage Regulation ◽

Buck Converter ◽

Output Channel ◽

Flyback Converter ◽

Input Multiple Output ◽

Voltage Deviation ◽

Single Input ◽

The Cross

A new single-input multiple-output (SIMO) converter is proposed in this work by incorporating flyback and buck converters in a master–slave configuration. The objective of this work is to address the cross regulation problem, achieve tight voltage regulation, improve the circuit form factor and attain a fast transient response for a SIMO flyback converter. The flyback converter maintains the output channels within 10% of their rated voltages and the SIMO buck converter is placed in series with the flyback converter such that it compensates for the output voltage deviation. Moreover, a time multiplexing switching scheme decouples output channel to eliminate the cross-regulation problem and remove the need for an additional winding transformer per each output channel. A type II compensator with a peak current mode controller was designed to achieve faster transient response which is critical for the proposed configuration. A thorough steady-state analysis was carried out on a triple output channel topology to obtain the design criteria and component values. MATLAB/Simscape modelling and simulation was used to validate the effectiveness of the proposed converter with the result yielding satisfactory transience even with load disturbance. Additionally, the result of the proposed converter is compared with previously published works.

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