Current Sharing Control of Two - phase Interleaved Parallel Boost Converter Based on Sensorless Current

Abstract

In this paper, based on the traditional single closed-loop voltage-type control method, a current sensorless current sharing control method is proposed to solve the current sharing problem in two-phase staggered Boost converters. Based on the characteristics and structure of the circuit itself, the equivalent dc circuit model of the converter is established. It is found that the main reason of phase current imbalance is the mismatch of effective duty cycle and phase parasitic resistance. In order to eliminate the current imbalance caused by them, the relationship between effective duty cycle mismatch compensation, parasitic resistance mismatch of each phase and duty cycle compensation is estimated, and the duty cycle of the second corresponding compensation is obtained based on the first phase. Compared with the traditional current-sharing control strategy, the proposed current-sharing control strategy does not need to collect phase current to judge and process the detected current, which reduces the complexity of the control loop in the controller, and also reduces the influence caused by low precision and high design cost of the current sensor. Finally, the simulation results on Matlab platform show that the equalizing effect of phase current has been significantly improved under various mismatches and different loads, which verifies the effectiveness of the equalizing current control.