Efficiency enhancement of high-power interleaved DC-DC converter by using an improved phase shedding control with phase equivalent resistance.

DC-DC converters generally maintain poor efficiency when operating at light to medium loads. This is primarily due to the fact that switching losses outweigh conduction losses significantly, while core losses remain constant regardless of the load conditions. In the case of the interleaved boost converter (IBC), this efficiency deterioration increases more than the conventional boost converter (CBC), when the number of phases increases. Therefore, an efficiency improvement is necessary for IBC under light load to medium load conditions. This paper proposed an enhanced phase-shedding control algorithm using phase equivalent resistance estimation for a 3-ϕ IBC, aiming to improve efficiency across all load conditions by incorporating automatic phase selection. Also, in the case of phase number selection, the required unknown parameter value i.e. phase equivalent resistance has been measured online in order to improve phase shedding performance. In addition, this algorithm is implemented by including the auto change inner loop-average current mode control (ACIL-ACMC) to maintain equal current sharing among the phases and voltage regulation during load variation as well as phase switching. The overall phase shedding control has been developed in the DSP (TMS320F28335) for the designed 7.5kW IBC.