Mixed-signal hysteretic internal model control of buck converters for ultra-fast envelope tracking

Abstract

Envelope tracking (ET) applications demand high tracking bandwidth and high efficiency using a DC-DC converter. Design based on small-signal models using fixed frequency digital pulse width modulator (DPWM) often results in limited closed-loop bandwidth. This paper proposes a mixed-signal hysteresis current control (MSHCC) in a DC-DC buck converter with an analog current-loop and a digital voltage controller c( ). This achieves robust stability and parameter insensitive current ripple by sampling the output voltage at the rising edge of high side gate signal. A fixed-gain power amplifier driven by a buck converter can be assumed to be a constant resistive load. Thus the load current information is directly obtained from the reference command, which further improves the tracking performance. The real-time tuning of c( ) using the proposed MSHCC achieves fast recovery with an inherent current limiting, and the use of the internal model control (IMC) further minimizes the tracking error. A fixed frequency operation can be achieved through a real-time band adaptation. The proposed controller is implemented using an FPGA device.978-1-4673-9550-2/16/$31.00 ©2016 IEEE

Experimental Investigation of an Adaptive Fuzzy-Neural Fast Terminal Synergetic Controller for Buck DC/DC Converters

“…In paper [3], the performance of the buck DC/DC converter is evaluated by variable structure controllers in which the output voltage is tracked and regulated in a good way; however, the robustness of these controlling techniques is not acceptable against noise, chattering, parametric variations, and disturbances, which makes them practically unsuitable [4]. Otherwise, because of the switching properties of buck DC/DC converter, digital discrete control methods like repetitive [5], dead beat [6], and internal model [7] controllers have been recommended for buck DC/DC converter. The main advantage of a repetitive controller is low output distortion; however, it has some limitations such as poor tracking, large memory capacity, poor performance, and slow dynamics.…”

“…Proper selection of the macro-variable (2) and judicious manifolds ensure the necessary performance and stability [20]. It is worth noting that SC law (7) can be rewritten as a solution to a Kolesnikov's problem (8). Choose the performance index as follows [21]:…”

“…Sustainability 2022, 14, x FOR PEER REVIEW The SC law (7) permits state trajectories to follow certain paths (3). P of the macro-variable (2) and judicious manifolds ensure the necessary pe stability [20].…”