Design and Analysis of Power Balance Mode Control Using Digital Control for Boost-Type DC-DC Converter

Power balance mode control (PBMC) is a new control method that adds a function of balancing input and output powers to current-mode control (CMC). As the input power is equal to the output power in a static state, PBMC does not operate, and the control changes to CMC. When there is a fluctuation due to a disturbance, the control to balance the power works because the input power and output powers are different. When the fluctuation is large, the control to balance the power works; when the fluctuation is small, it is equivalent to CMC. In this study, the PBMC operation was analyzed in more detail, and it was found that the PBMC operation and CMC operation switched seamlessly depending on the magnitude of fluctuation. Furthermore, a design method for digital PBMC was developed and analyzed comprehensively through experiments. As a result, even though the frequency characteristics of the open-loop transfer function and output impedance of PBMC by small-signal analysis are the same as those of CMC, the output voltage fluctuation is reduced to about 1/3 of that of CMC. Since the PBMC can suppress the output voltage fluctuation without requiring a high gain crossover frequency, it can ensure high response performance, noise rejection, and stability of the control system. In addition, output voltage fluctuations can be suppressed, thus contributing toward downsizing of power conversion circuits and increased power density.