Predictive control has emerged as a promising control method in a variety of technological fields. Model predictive control, as one of the subdivisions of this control method, has found a growing number of applications in power electronics and motor drives. In practical implementations, model predictive control faces performance degradation of the controlled plant due to its dependency on a model. There are considerable numbers of review papers that are devoted to the different points of view of predictive control. However, the existing literature lacks a review study that addresses the solutions for parameter dependency of the model predictive control method. Recently, model-free predictive control has been used in drives and power electronics as a solution for dealing with the model-dependency of the model predictive control method. There are many papers that have used such methods. In this paper, a classification is proposed for the different implementation types of model-free predictive control or similar methods that address model parameter uncertainties. Additionally, a comparison between the methods is also presented.

Dynamic wireless power transfer (WPT) for charging electric vehicles (EVs) overcomes some of the problems associated with EVs battery size and weight as well as distance range limitation and long charging duration. High efficiency and fixed output voltage of WPT systems are of great importance for reducing operating cost and facilitating battery charging, respectively. On the other hand, utilizing the maximum power transfer capability of a WPT system leads to a capital cost saving of the system. In this article, the product of transferred power efficiency and input power factor (η·PF) is regarded as a criterion to make near full usage of the system power transfer capacity as well as reduce the capital and operating cost of the system. An optimal frequency-tracking method is proposed to maximize η·PF of the system taking into account possible abrupt changes in the coupling coefficient of the WPT system due to deviations of EV from alignment with the track along the road. In addition, the output voltage of the system is regulated simultaneously by an on-line adjustment of the primary inverter duty ratio. The optimal frequency-tracking method and voltage regulation are validated by extensive simulation and experimental results.

With the increasing penetration of distributed energy resources into islanded microgrids, a grid-forming inverter (GFI) has become the key element interfacing renewable energy sources. Usually, the GFI is employed with an output filter to minimize the harmonic content achieving high-quality output voltage regulation. To this end, model-predictive control (MPC) has been widely proposed to control the output voltage of GFI systems due to the high-quality performance, fast control response, and straightforward handling of constraints. However, an accurate model of the system is required for the conventional MPC to avoid a suboptimal performance under uncertainties. To overcome this known drawback, a novel model-free predictive control is proposed in this article. Consequently, the output voltage of an $LCL$ -filtered GFI is regulated without the knowledge of the physical model.

Fast transient and smooth steady state performance of wind energy conversion systems (WECSs) is essential for sustained power conversion and grid code fulfilment including low voltage ride through capability. In this paper, an analysis of permanent magnet synchronous generator (PMSG) based WECSs under vector control and direct torque control provides the basis for combining salient features of the two control methods into a reliable and effective control system to provide enhanced machine performance. The system includes two hysteresis current controllers in connection with an inverter-switching table. The proposed control provides fast transient and smooth steady state performance for machine side converter of PMSGs, which controls DC-link voltage under grid fault conditions. Extensive simulation results on a 2 MW PMSG based WECS demonstrate the desired performance of the proposed control system under both grid-normal and -fault conditions.

A high efficiency and a constant voltage at the output stage are among the major concerns in wireless charging of dynamic electric vehicles. They are usually achieved by additional converters or asymmetric switching which suffer from high cost and hard switching. To overcome these drawbacks, a variable-frequency retuning approach is proposed in this paper with LCL-Series compensation. As opposed to conventional control methods with resonance frequency as target operating frequency, this approach uses a new optimum frequency which enables ZVS. Also, it minimizes the conduction loss of the inverter switches in a wide range of load and coupling coefficients. In addition, it improves the total system efficiency up to 6% together with an increase in the power transfer capability. Using the proposed method, both sides' currents increases up to 45% depending on the load. To find the optimum frequency in a system without resonant parameter information, an on-line maximum efficiency search method based on Perturb and Observe is employed. Extensive simulation results using PLECS, together with experimental results from a laboratory setup are presented to confirm the effectiveness of the proposed method under varying load and coupling.

In motor drives supplied through wireless power transfer (WPT) systems, a high frequency inverter and a low frequency one are commonly used in the primary and secondary sides of the system, respectively. This arrangement causes reduced reliability and efficiency, and high cost. Besides, using an electrolyte isolator like big dc capacitor, shorten the system lifetime. This capacitor is usually located in parallel with the motor drive system. So, the capacitor fail leads to a total system failure. In this paper, a multi-functional single inverter used in the primary side dispatch as the high-frequency ac power via a magnetic link as well as driving an induction motor without any extra inverter in the secondary side. This is obtained by using a simple AC/AC chopper in the secondary side as a wave shaping convertor. In this way, the desirable ac power can efficiently be injected to the motor. The modeling and mathematical analysis of the proposed wireless drive are presented. Also, the performance of the drive under an open-loop V/F control system is verified by simulation and experimental results.