Sensorless Current Sharing Scheme for Multiphase Buck Converters Using Fuzzy PI Controller

Multiphase buck converters usually use common current technology to achieve uniform current sharing between multi-phase. The traditional current sharing scheme requires multiple current sensors. It not only reduces the reliability of the system, but also increases the volume and cost. A sensorless current sharing control scheme using fuzzy PI controller is proposed. The scheme adopts double voltage closed-loop control without the need for current sensing. The difference between the sampling output voltage value and the preset reference value is input into fuzzy PI controller output duty cycle <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$d$</tex>. The difference of input capacitor voltage ripple value is input into fuzzy PI controller. Fuzzy PI control is used to output the compensation duty cycle Δd<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i</inf> of each phase, and the duty cycle d of each phase is compensated to achieve the purpose of current sharing. Finally, taking the three-phase buck converter as an example, the simulation results of the control method are given, and the feasibility of the scheme is verified.