Control of DC–DC Converter and DC Motor Dynamics Using Differential Flatness Theory

Abstract

The article proposes a method for nonlinear control of the dynamical system that is formed by a DC-DC converter and a DC motor, making use of differential flatness theory. First it is proven that the aforementioned system is differentially flat which means that all its state vector elements and its control inputs can be expressed as differential functions of primary state variables which are defined to be the system's flat outputs. By exploiting the differential flatness properties of the model its transformation to a linearized canonical (Brunovsky) form becomes possible. For the latter description of the system one can design a stabilizing feedback controller. Moreover, estimation of the nonmeasurable state vector elements of the system is achieved by applying a new nonlinear Filtering method which is known as Derivative-free nonlinear Kalman Filter. This filter consists of the Kalman Filter recursion applied on the linearized equivalent model of the system and of an inverse transformation that is based on differential flatness theory and which enables to obtain estimates of the initial nonlinear state-space model. Moreover, to compensate for parametric uncertainties and external perturbations the filter is redesigned as a disturbance observer. By estimating the perturbation inputs that affect the joint model of the DC-DC converter and of the DC motor their compensation becomes possible. The efficiency of the proposed control scheme is further confirmed through simulation experiments.

New “Full-Bridge Buck Inverter–DC Motor” System: Steady-State and Dynamic Analysis and Experimental Validation

“…In accordance with the aforementioned, different approaches have been proposed for a DC motor fed by a DC/DC Buck converter when the unidirectional rotation of the motor shaft is considered [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. This unidirectional rotation emerges because the Buck converter only delivers unipolar voltages.…”

Bidirectional Tracking Robust Controls for a DC/DC Buck Converter‐DC Motor System

“…This system, in general, is composed of three stages, namely, a DC/DC Buck converter, a complete bridge inverter, and a DC motor. Unlike the arrangements presented in [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29], such configuration allows the bidirectional driving of the motor shaft. The system average model presented in Figure 1, which was deduced and experimentally validated in [35], is given by…”

“…More recently, Khubalkar et al in [22] presented a stand-alone digital fractional order PID tracking control for the DC/DC Buck converter-DC motor system. Rigatos et al in [23] designed a flatness-based control to solve the trajectory tracking problem. Another solution was proposed by Nizami et al in [24], where a neuro-adaptive backstepping control for the angular velocity tracking was developed for the aforementioned system.…”

Robust Predictive Speed Regulation of Converter-Driven DC Motors via a Discrete-Time Reduced-Order GPIO

“…To this end, several advanced control approaches have been investigated to enhance the performance specifications from different aspects, i.e. hierarchical/nonlinear PID control [11]- [14], [19], passivity-based control [9], [17], [18], model predictive control [27], adaptive control approach [16], [28], robust control [6], fuzzy control [29], H ∞ control [30], and active disturbance rejection control [6], [15] for converter driven DC motor systems.…”