Single-Loop Current Sensorless Control for Single-Phase Boost-Type SMR

In this paper, the first single-loop current sensorless control (SLCSC) in continuous current mode (CCM) for single-phase boost-type switching-mode rectifiers (SMRs) is developed and digitally implemented in a DSP-based system. Compared to the conventional multiloop control with one inner current loop and one outer voltage loop, there is only one voltage loop in the proposed SLCSC, where the voltage loop's output is used to shift the nominal duty ratio pattern generated from the sensed input and output voltages. Because of no current loop, the efforts of sampling and tracking inductor current can be saved. It implies that the proposed SLCSC is simple and very adaptable to the implementation with mixed-signal ICs. First, the effects of shifting nominal duty ratio pattern on the input current waveform are analyzed and modeled by considering the inductor resistance and conduction voltages. The result of analysis shows that the pure sinusoidal current can be inherently generated by the nominal duty ratio pattern where the current amplitude is roughly proportional to the controllable phase of nominal duty ratio pattern. Then, a voltage controller is included to regulate the DC output voltage by tuning this controllable phase. Finally, some simulated and experimental results have been given to demonstrate the performance of the proposed SLCSC.