A comparison of steady‐state characteristics of buck‐type DC‐DC converter using DSP

Abstract

SUMMARYIn this paper, we describe the relationship between the control constants and the output voltage regulation characteristics of a buck DC/DC converter for a digital control system using P-I-D control, the minimum phase FIR filter, and the moving average constructed from digital signal processors. Furthermore, the digital control method and its control constants were studied comparatively from the perspective of suppressing the oscillations based on the limit cycle. We found that when an 8-bit analog-to-digital (A-D) converter having a quantization width of about 80 mV was used, we could obtain excellent results similar to the minimum phase FIR filter and the moving average, achieve an excellent output voltage regulation of less than 1.3% for fluctuations from a light load to the rated 2 A for the target 10 V, and suppress oscillations to less than 20 mV. In the P-I-D control method, adequate output voltage regulation characteristics were obtained, but oscillations could not be suppressed.

Topics of digital control approaches for future-oriented power converters

“…Thus, it is difficult to implement AI technologies to high switching frequency power conversion units directly by the present technology level. Currently, it is important to use simple digital control approaches instead of AI technologies as the predictive control method for predicting the optimal operation points for maximum performance [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22].…”

“…The period from the sampling timing to the switching off-timing can be considered as the delay time, which is shown as T delay in this figure. The delay time gives a negative influence on the stability and transient response [5][6][7]. Many digital control approaches have been suggested to suppress the influence of delay time and improving the transient response [8][9][10][11][12][13][14][15][16].…”

A New Fast Digitally Controlled DC-DC Converter

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Accuracy digital control for boost dc-dc converter

“…This T on regulates the output voltage e o. The on-time interval N Ton of the P control circuit is represented as follows [5], [6];…”