Comparative study of adaptive current‐mode controllers for a hybrid‐type high‐order boost converter

Abstract

A comparative study of two adaptive current-mode controllers for a high-order hybrid-type dc-dc boost converter is presented. The implementation of the traditional current-mode controller for this converter requires the knowledge of the nominal value of the load resistance to compute the control signal. As such, it is unable to handle systems with uncertain loads well. To address this, an adaptive law is used to estimate the load conductance in order to generate the reference current input. In this adaptive law, the derivative of the estimator is optimised as well as bounded. Moreover, the converter has two inductor currents which can be used for feedback purposes. Considering this, two adaptive current-mode controllers using the input and output inductor currents of the converter are separately designed to find the most appropriate inductor current for the implementation of the proposed controller. Finally, some simulation and experimental results comparing the performance of the adaptive controller using the output inductor current with that of the traditional current-mode controller are also presented.

Fixed frequency integral sliding‐mode current‐controlled MPPT boost converter for two‐stage PV generation system

“…The simplified existence condition for steady-state operation (15) with the assumed sliding surface can be derived as by substituting (11) in (14) with the consideration of system dynamics (5) as…”

Fixed- and variable-frequency sliding mode controller–maximum power point tracking converter for two-stage grid-integrated photovoltaic system employing nonlinear loads with power quality improvement features

“…Thus, the design of the sliding coefficients depends on the bandwidth f BW of the desired frequency response. According to Equations (13) and (15), the control parameters obtained are K 1 = 1 and K 2 = 10 for the 1-kHz bandwidth of the controller.…”

“…2,3,11 Focusing the nonlinear controllers, particularly sliding mode controllers (SMCs), is a better candidate than conventional linear controllers for mitigating such low-frequency oscillations and load perturbations due to their excellent characteristics of stability, simpler implementation and robustness against parameters which are common in PV system. 4,12,13 However, SMC approach applied to MPPT DC-DC converter has certain limitations in the design of filter circuit due to variable operating frequency and high chattering magnitude such as PV voltage fluctuations. Hence, to ensure stability of a voltage-oriented MPPT algorithm with fast settling time, alleviating high chattering magnitude and mitigating low-frequency oscillations of the PV voltage especially in grid-connected environment, the necessity of constant frequency operation of SMC-MPPT converter is an important one in this concern.…”

Modified voltage‐mode controller for the quadratic boost converter with improved output performance

“…where z˙d, v˙C o and σ are the first-order time derivatives of z d , v C o and σ, respectively. Now, substituting (4), (18), (19) and (22) into (23) yields the following equation: (see (24)) . Setting the state variables i L 2 , v C o and σ equal to their equilibrium values i L 2 ∞ , v C o ∞ and σ ∞ , respectively, gives the following remaining dynamics of the closedloop system:…”

“…In contrast to the buck converters, these boost converters present nonminimum phase dynamic characteristic which make it difficult to design the controller using only output voltage for feedback purposes [18]. Therefore, the two-loop current mode controllers are usually used for the regulation of the boost converter, in which the converter output voltage is regulated via the control of the inductor current [17][18][19][20][21][22][23]. This scheme provides an improved settling time and a wider control bandwidth [21,22].…”