A Nonlinear Integral Backstepping Controller to Regulate the Voltage and Frequency of an Islanded Microgrid Inverter

Abstract

The islanded operation mode of a microgrid system is usually affected by the system uncertainties, such as the load, source, and parameter variations. In such systems, the voltage and frequency must be regulated to maintain the power quality during islanded operation. As an approach to control the voltage and frequency, in this study, a decentralized nonlinear integral backstepping controller for the voltage source inverter used in an islanded microgrid is developed. First, the dynamical model of the inverter-based distribution generations (DGs) in microgrid system is developed. Subsequently, the model-based controller for the microgrid is built using dynamics of inverter-based DGs and Lyapunov theory, which could eliminate the voltage and frequency deviations in the system under different uncertainties. To ensure the system stability, a control Lyapunov function is adopted. Considering the influence of irradiations and other meteorological variables fluctuations a battery energy storage (BESS) is applied on the DC side to suppress the fluctuations of output power of DGs. Furthermore, the efficiency of the designed controller was validated through simulations in the MATLAB/Simulink environment under different scenarios and effectiveness of the proposed framework is further validated by real-time hardware in loop (HIL) experiments. In addition, the performance of the proposed controller is compared with a conventional backstepping (BS) controller. The comparison results demonstrate that the efficiency of the designed controller in terms of obtaining steady-state operating conditions is better than that of the BS controller.

Design of a new backstepping controller for control of microgrid sources inverter

“…It consists of two arms with bi-directional couplings insulated gate bipolar transistors (IGBTs) or metal-oxide semiconductor filed effect transistor (MOSFET) with reverse parallel diodes that operate complementarily. The control signal μ is generated by the PWM generator and has a value between {1, -1} and in summary the binary commands μ1 and μ2 are of the two switching parts [7], [8].…”

“…This model is a system with variable structure: 𝑣𝐴𝐵 is not a continuous variable and can be two discrete values of E and -E, so it is inappropriate to design a continuous control rule. To overcome this problem, we often have to use the average model (widely used for modeling static converters) [8], [9] the switching period in this case is assumed to be much smaller than the dynamic system. In our study, this is very acceptable.…”

Adoptive Inverter Controller for Microgrid in Islanded Mode

“…The resistive loads, which can be considered are incandescent lamps, heaters, etc. The electric motors, solenoids, etc., can be categorized as RL loads [24]. The passive load of constant power load (CPL) considered is instantaneous impedance, which is of positive value [25].…”

Optimized Nonlinear Integral Backstepping Controller for DC–DC Three-Level Boost Converters

“…In [26], a fault-diagnosis control for the five phase induction motor based on a BS controller for ensuring the desired dynamic has been introduced. In [27], an integral backstepping controller for an inverter applied in an islanded micro-grid has been developed. A robust integral backstepping controller has been proposed for the energy management of Plugin hybrid electric vehicles [28], regarding the reference generation, voltage regulation, and smooth current tracking.…”