Digital control of DC-DC boost converters with inductor current estimation

This paper investigates a digital control of DC-DC boost converter operating in continuous-conduction mode (CCM) sensing only the output voltage and possibly the input voltage. In order to improve the dynamic performance compared to voltage mode control, the inductor current is estimated and used for the implementation of an internal sensorless current loop. Different solutions, either based on the prediction of inductor current variations or on state observers, are discussed, showing that the sensorless current mode control gives some advantages only if input voltage feedforward is used. The digital control has been implemented in a field programmable gate array (FPGA) using a hardware description language (VHDL), providing flexibility and technology independence. Experimental results on a 100 W DC-DC boost converter confirm the properties and limitations of the proposed approach.