Large-signal feedback control of a bidirectional coupled-inductor Cuk converter

Abstract

Under conditions of order reduction, a nonlinear control of a bidirectional coupled-inductor Cuk converter suitable for large-signal applications is presented. The converter is accurately modeled as a second-order bilinear system and the conditions established for local controllability. The integration of converter state equations and the subsequent introduction of a linear recurrence between the output variable and an external reference signal lead to a nonlinear control law that is implemented by means of an analog divider, standard operational amplifiers, and a pulse-width modulator. As a result, the output variable follows proportionally the reference signal, this allowing the obtention of different types of power waveforms in the converter output. Experimental results verify the theoretical predictions.

Digital Loss-Free Resistor for power factor correction applications

“…Replacing (11) in (16) Solving (17) we obtain that control ߬ሺ݊ሻ should be chosen as where ߬ ሺ݊ሻ stands for "equivalent control" which is the control law that yields the motion in the surface ‫ݏ‬ሺ‫ݔ‬ሻ ൌ 0. Substituting (12) in (19) the following expression is obtained…”

“…For that reason, it is necessary to obtain a good discrete-time model of the system before trying to implement any discretized analog control. For that reason, the bilinear recurrence in [19] for converters that operate in PWM and continuous conduction mode (CCM) has been taken as the starting point.…”

Digital Control of a Buck Converter Based on Input-Output Linearization. An Interpretation Using Discrete-Time Sliding Control Theory

“…It can be observed that, although the equation corresponding with the voltage regulator is linear, Equations (17), (19), (26) should be linearized around the equilibrium point so that the choice of coefficients k 1 , k 2 or k n , β can be carried out by means of linear control techniques. The analysis of the linearized equations together with Equation (35) in the z domain results in the following transfer equations…”

“…This has the advantage of simplifying the control implementation with respect to the hybrid control realizations found extensively in the literature. The starting point of the controller proposed in this article is the bilinear recurrence developed in [26] for PWM converters in CCM, which is reviewed in Section 2. The proposed nonlinear controller is obtained by input-output linearization and presented in Section 3, in which a discrete-time sliding mode interpretation is also provided.…”

Analysis of a bidirectional coupled-inductor Cuk converter operating in sliding mode

“…where is given by (17). The equilibrium point of (19)- (22) results from the intersection of the curve of equilibrium points and the discontinuity surface. Namely, (27) and therefore will be given by (28), shown at the bottom of the page, or if and…”