The design of an on-line generalised predictive control (GPC) technique with a novel identification method is presented in this paper for a single-phase full-bridge inverter in the presence of different disturbances. The controller uses system discrete-time model to reach the control variables with a prediction over these values, followed by computing a cost function for control aims. However, in this controller, the need for the mathematical model of the system is removed since the black-box identification strategy is used. Moreover, GPC structure has many advantages including low computational complexity, systematic design procedure, and fixed switching frequency that makes it a good alternative for practical applications. Various disturbances can have a negative impact on a DC-AC inverter; thus, considering robust dynamics and ease of implantation, the GPC scheme is used along with an improved exponential regressive least square identification algorithm as an adaptive strategy in the controller. Moreover, the prediction horizons of this controller have been increased, resulting in its low steady-state error and better performance. Furthermore, harmonics in the sinusoidal signal can decrease the total efficiency of the system; thus, an LC filter is used to reduce the level of total harmonic distortion. However, the stability of the filter is the most challenging issue in designing a suitable controller. Finally, the strength of the current controller is verified using experimental and simulations results. INTRODUCTIONNowadays, power inverters are utilised in connecting renewable energy sources for power generation. Single-phase inverters are well-known and used in various industrial applications. A DC-AC H-bridge voltage source inverter (VSI) topology is selected here to feed different linear loads [1,2]. The generated sinusoidal waveform of an inverter must have a constant amplitude and frequency with a minimal rate of THD. To limit the THD level, various filters are suggested including LLCL, L, LC, and LCL. In fact, characteristics of the LC-type filter, make it can be the most suitable one for stand-alone structures (load connected) [3][4][5][6]. Stability proof of the filter is the primary concern which can harm system dynamics; thus, two strategies were presented for this challenge: passive and active damping schemes.In passive damping strategy, the inductor is modelled with a series resistor, while total system efficiency can be affected. However, for the second scheme, a closed-loop control strategies have been introduced [7]. However, the following This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

A cascade technique with two control loops is designed for a DC\DC Buck-Boost converter that is a right half-plane zero (RHPZ) structure called a non-minimum phase system. This concept presents several challenging constraints for designing well-behaved control techniques. Cascade controllers can provide various benefits compared with single loop controllers such as higher safety, higher robustness, and higher stability. This strategy assumes the system as a black-box structure without the need for a mathematical model of the system. This benefit can decrease the computational burden and provides faster dynamics along with ease of implementation. This technique consisted of an outer Fractional-order PID voltage controller tuned with the Antlion Optimizer (ALO) algorithm, which provides a reference current for the inner control loop of the Neural Network-based LQR (NN-LQR) controller. The basic principle in cascade controllers is a more rapid performance of the inner loop that has been satisfied with the NN-LQR strategy, which optimizes and tunes the gains of the LQR controller and shows faster dynamics and higher robustness. It should be mentioned that the number of neurons is limited to 2 and 4 in each layer to decrease the computational burden with lower complexity. Also, the ALO algorithm is a modern nature-inspired algorithm used to tune the PID gains with better results under-constrained problems with diverse search spaces. Considering the negative impacts of various disturbances on a power converter, a Fractional-order-based PID (FO-PID) control technique is a proper alternative since it shows higher robustness in load uncertainties along with better dynamical responses based on its extra degree of freedom. Moreover, to evaluate the superiority of this controller, two other controllers are designed using the PSO algorithm for PID and FO-PID controllers. Finally, the presented cascade controller has been tested in various working conditions through simulation and experiment results.