Fixed-frequency Dual PWM Interleaved Boost LLC Resonant Converter for A Wide Input Voltage for Photovoltaic Applications

Step-up converters are integral to photovoltaic generation and electric vehicles. This paper presents an interleaved boost LLC resonant converter that offers reduced input current fluctuations, an elevated step-up ratio, and utilizes a dual PWM control mechanism, providing improved voltage stabilization via two independent control variables. PWM control of the primary-side interleaved boost topology not only elevates the voltage but also minimizes variations in the input current. Simultaneously, duty cycle ratio of the auxiliary switches in secondary side determines the extent of double voltage rectification method versus quadruple voltage rectification method, which extended its ability to regulate voltage. Moreover, the rectifier structure halves the voltage stress on the secondary diodes. Importantly, utilizing fixed-frequency control in the converter enhances magnetizing inductance, thereby reducing conduction loss, compared with PFM control. Furthermore, this approach simplifies magnetics design and optimization. To validate the proposed design, a 300W prototype with 45 to 100V input voltage range and a constant 500V output voltage is established, whose experimental results verify the theoretical advantages and practical feasibility.