Comparison of Current Balancing Configurations for Primary Parallel Isolated Boost Converter

Different current balancing configurations have been investigated for Primary Parallel Isolated Boost Converter (PPIBC). It has been shown that parallel branch current balancing is possible with several configurations of coupled/uncoupled inductors. Analytical expressions for branch currents have been derived for different cases of gate signal mismatch causing current imbalance. It has been observed that turn-on and turn-off delays in parallel power stages of the PPIBC have different effects in the branch currents deviating from ideal. It has also been observed that in some configurations inductance differences due to core tolerances play an important role in current imbalance. Analytical and simulation results have shown that another side effect of the gate signal delay and inductor value difference is additional voltage stress over the switches during the mismatch times. Advantages of each configuration in terms of effective current balancing, efficiency and manufacturing simplicity have been highlighted. Simulations with ideal components for each case have been carried out to confirm the analytical derivations. Experimental results have also been included to show the performances of different configurations where component non-idealities like transformer leakage inductances also become effective.