CIEP A dynamical 2006 Puebla, MEXICO control for the October 16-18 i implement Domingo Cortes, Jaime Alvarez Centro de Investigacion y Estudios Avanzados del IPN, Departamento de Ingenieria Electrica. Av. IPN 2508, C. P. 07360 Mexico, D.F. Email: { dcortes, jalvarez } @ cinvestav.mx sliding-mode boost converter: ;ation details Andres Bautista Universidad Aotonoma Metropolitana - Azcapotzalco Av. San Pablo 180, C. P. 02200, Mexico, D.F. Email: andresbg@gmail.com Abstract- An experimental evaluation of a dynamical sliding- mode control for power converters which has been recently proposed is presented in this paper. This controller is endowed with notable characteristics predicted in theory and observed in simulations, among others: it is robust under load and input voltage variations and does not require current measurements. Although it is highly nonlinear, it is easy to implement. Fur- thermore simple conditions for stability have been provided. All this characteristics are evaluated in practice in this work. The design procedure is presented by means of an example and implementation details are thoroughly explained. I. INTRODUCTION Over the last decade, different nonlinear controllers to im- prove the performance of dc-dc converters have been proposed [1], [2], [3], [4], [5], [6], [7], [8]. Most of these controllers, achieve the goal of controlling the converter and detailed stability analysis is provided. However, most of them are difficult to implement or have a rather slow response. Some of them depend on the load [1], [2], [6], [7], which makes them non-robust, require multiplications or divisions [3], [5], [6], [7] or need a reference for the inductor current [4], [8]. Due to these facts, the current-mode controller [9] is still a good alternative to control dc-dc converters. Motivated by its robustness properties, sliding-mode control has been used in power converters from some time ago [4], [10], [11]. Robustness, performance and implementation of a particular sliding-mode control depends on its sliding surface. Sliding surfaces typically used are the inductor current error [11] or a linear combination of inductor current and voltage errors [4], [10]. Recently, a new nonlinear sliding mode controller has been proposed [12]. The sliding surface of this controller is dynami- cal, can be easily implemented using standard electronics parts and does not depend on the inductor current. Simulations of this controller have been shown that it is robust under load and input voltage variations and has a performance comparable This work was partially supported by CONACYT Mexico under grant 44969 to current-mode controller whereas it is easier to design. Furthermore, stability can be assured if simple relationships between the controller and converters parameters are met. However, these characteristics, predicted theoretically and ob- served in simulations, has non been validated by experimental results. In this paper, the design procedure of this controller is explained and the implementation details are thoroughly described. Although methodology can be applied to different types of converters, the paper is focused on the boost converter. After of deriving the boost converter model, the controller is presented in detail in section II. In Section III a boost converter and its controller are designed for a particular specification. Implementation details of the controller are described in Section IV. Experimental results are presented in Section V. Finally, some conclusions are given in Section VI. II. THE CONTROLLER Figure 1 shows a simplified diagram of the boost converter. Applying Kirchhoff's laws a model for each switch position can be obtained . For u= 1: Vin ZL =- Z2 Z2 -RC (la) (lb) (Ic) * For u = 0: Vin -Z2 L Z2 Zi Z2 =--+- RC C (2a) (2b) (2c) where zi is the inductor current and Z2 is the capacitor voltage, that is, the output to be controlled. Combining both models, one yields to: Vi- (1 -U)Z2 L Z2 (1 -U)Z Z2 RC C yJa) (3b) 1-4244-0545-9/06/$20.00 ©2006 IEEE