A Coupled-Inductor-Based Bidirectional DC–DC Converter With High Voltage Conversion Ratio and Sensorless Current Balance

In this article, a coupled-inductor (CI)-based bidirectional dc–dc converter with a high voltage conversion ratio (VCR) and low voltage stress is proposed. The topology can achieve high VCR by employing two CIs; moreover, the interleaved technique overcomes the defect of large current ripple in CI. A sensorless current balance between the two CIs is also realized without an auxiliary circuit and complex control method. The pulsewidth modulation plus phase-shift control is employed, where the duty cycle D is used to adjust the VCR, and the phase-shift angle ϕ is used to control the direction and amount of the transferred power. In addition, all switches can achieve soft-switching under a wide operation range. The steady-state analysis of the proposed converter is analyzed in detail, followed by comprehensive experimental verification under a 1-kW prototype.