# Sensorless Control for DC-DC Boost Converter via Generalized Parameter Estimation-Based Observer
###### Abstract
(**a**) Battery-power system, (**b**) wound rotor asynchronous motor system, (**c**) wind generator system, (**d**) solar cell system. back control scheme. That is, it should be supposed that all of the states can be measured. However, the current sensors and their processing circuits cause extra hardware costs, delays and noise in the system. They can also harm the reliability of the power system. Therefore, current sensorless control techniques can provide cost-effective and reliable solutions for various boost converter applications. In References [18; 19], based on the immersion and invariance (I&I) technique, a sensorless controller, which combines a nonlinear controller and state observer, is developed to stabilize boost converters. It is noted that the exponential stability of a closed-loop system is ensured. It is reported in [20; 21; 22; 23; 24] that the well-known Luenberger observer is designed to reconstruct the current under continuous conduction mode (CCM) or discontinuous conduction mode (DCM). By combining this with some advanced controllers, sensorless controllers are derived. A discrete current observer proposed in [25] is used to estimate the states of the converters. A unified current observer devised in [26] is proposed for six kinds of converters. By incorporating the progressive control method, the sensorless control algorithm can be designed. In addition, the small-signal injection technique [27], extended Kalman filter method (EKF) [28; 29], high gain observer [30] and sliding mode observer [31; 32; 33] are developed to estimate the current of boost converters. For the interleaved boost converter, authors have proposed a sensorless current balance controller on the basis of the phase current estimate [34]. By designing a first-order observer for estimating the voltage derivative, the current estimate is obtained [35]. After that, an output feedback controller is proposed for boost converters by means of combining the PD controller and current observer. In [36], the authors design a sensorless control scheme for boost converters from the view of the frequency domain. In [37], an adaptive nonlinear observer is devised to estimate the current and unknown parameter of boost PFC AC/DC converters. It is noted that the abovementioned works contain two main problems. First, all of the previous controllers only ensure the asymptotic/exponential convergence of the state observer. Second, the proposed results center on a particular topology of converters. It should be noted that the finite-time convergence (FTC) will contribute to improving the transient and robustness. Therefore, for the simpler case of a buck converter described by a linear system, authors have proposed different kinds of finite-time observers to reconstruct the knowledge of the current [38; 39; 40]. However, there are no studies about designing the finite-time state observer for the complicated case of a class of converters expressed by a nonlinear system. Being aware of these two problems, a generalized parameter estimation-based observer (GPEBO) proposed in [41] is adopted to estimate the inductor current of a boost converter with FTC. In addition, a PI-PBC is designed to stabilize it. The main contributions of this paper are as follows. 1. A PI-PBC is proposed to stabilize a DC-DC boost converter with exponential stability. 2. A GPEBO is constructed to estimate the inductor current. It is noted that the FTC of this observer is ensured and a very weak persistence of excitation (PE) condition is needed. Moreover, this result can be easily extended to a large class of converters. 3. The experimental results are given to assess the performance of the proposed sensorless control law. The remainder of this paper is as follows. The model of this system is described in Section 2. Subsequently, in Section 3, a sensorless control law is developed by combining PI-PBC and GPEBO. The simulation and experimental results are shown in Sections 4 and 5, respectively. The conclusion is given in Section 6.