Current‐mode control of DC–DC power converters: a backstepping approach

Abstract

Current-mode control is a robust industrial DC-DC power converter control scheme that has been successfully tested, is widely accepted, and is commonly implemented with conventional linear P and PI controllers. The need of more systematic designs with enhanced performance has motivated recent studies with linear and nonlinear advanced techniques, but the rigorous understanding and substantiation of the underlying key robust functioning capability are still lacking. In this paper, a constructive control approach is employed to study the current-mode control problem of a class of DC-DC power converters, yielding a cascade control design methodology with: a robust convergence criterion coupled with a systematic and transparent construction-tuning procedure, a rationale to explain the robust controller functioning, and a unified framework to interpret and compare the proposed controller with the existing conventional and advanced control designs. The implementation and functioning of the proposed control design is illustrated experimentally with a boost converter. * a control design methodology with a robust convergence criterion coupled to a systematic and transparent construction-tuning procedure, * a rationale to explain the robust functioning of CMC, and * a unified framework to look at the existing conventional and advanced control designs.First, a small-signal model of the DCPCs is obtained. This model displays clearly the cascade structure of the duty-ratio-current-voltage signal path, and the non-minimum-phase nature of the output voltage regulation problem for the boost and buck-boost converters. Then, motivated by backstepping design ideas [11][12][13] and using a low-gain/high-gain geometric approach, a robustly convergent cascade (multiloop) controller is built. Subsequently, it is shown that the resulting controller can be realized as a cascade of classical linear PI compensators, which resembles the structure of the CMC used in industry. The corresponding closed-loop dynamics is studied, yielding a robust convergence criterion, exhibiting the limiting

An immersion and invariance based input voltage and resistive load observer for DC–DC boost converter

“…Therefore, different studies have tried to eliminate mentioned weakness applying nonlinear controllers. In this regard, various nonlinear controller such as sliding mode [13][14][15], passivity-based control [8,16] and backstepping control [17] have been suggested. However, this kind of controller requires an exact information of system states to present control effort and this drawback is significant.…”

Improved static and dynamic performances of a two‐cell DC–DC buck converter using a digital dynamic time‐delayed control

“…These controllers that manipulate the error signal to determine the desired control action have classically been analog systems. Many control approaches can be used for modern power converters [7][8][9][10]. In [7], authors use a sliding mode approach to design a controller for a two-cell converter.…”

“…The main drawback of this control technique, despite its popularity, is a variable switching frequency and undesired chattering effects. In [8], a global hybrid dynamical approach is used while a backstepping solution with the current mode control have been studied in [9]. One cycle control has been studied for power converters working in both continuous and discontinuous conduction modes in [10].…”

Accounting for coils magnetic saturation in controlling DC-DC power converters

“…For PWM DC-DC converters, the control problem has been dealt with following different nonlinear control techniques. These include passivity techniques [2], feedback linearization and flatness methods [5], sliding mode control [3]- [4] and backstepping control [6]- [9]- [13]. The obtained regulators were formally shown to meet their objectives, namely output voltage regulation and reference output tracking, in presence of small input voltage fluctuations and load changes.…”