## 1 Introduction  
In a wind power generation system (WPGS) scheme, rectifiers are used to extract power from a renewable energy source in a controlled manner [1], which is then delivered to the grid by means of a voltage source inverter (VSI). The most commonly used topology for this application is the back-to-back converter, which achieves bidirectional power flow [2]. Nevertheless, when bidirectionality is not needed, using an uncontrolled rectifier + three level boost chopper represents a cheaper alternative than the former. Three level boost chopper has a large number of advantages compared with the conventional boost converter, such as: (a) comparing to the previous boost converter, the inductor current ripple of the boost-TL converter is lower, reducing the generator torque ripple; (b) the voltage stress of the power device is less than that of the conventional boost converter, so the output voltage of the generator and the capacity of the converter can both be increased; (c) in the case of the same inductor current, the switching frequency is half that of the conventional boost converter, so the switching losses are less; (d) the boost-TL converter boosts the DC output voltage from the rectifier at low speeds, so it also allows the wind power generator to operate over a wider speed range. Therefore, the boost three-level converter is widely adopted in modern power electronics apparatus. In [3], the MPPT and the methodsof the voltage balancing control for the boost three-level converter are proposed, however, MPC is not adopted. In [4], a novel predictive controller for a series-interleaved multicell boost three-level PFC converter has been presented. In wind power generation systems, multilevel converter topology has received increasing attention in order to meet the ever-increasing stand-alone capacity of wind turbine generators and the ever-increasing current and voltage levels of converters. The neutral-point-clamped (NPC) inverter and T-type inverter are commonly adopted in the three-level inverter topology, compared with the NPC inverter, the T-type three-level structure also has many advantages, such as: (a) small number of components; (b) the control signal has no stop sequence problem and is easier to control; (c) low switching loss and high efficiency; (d) less driving power; and (e) in the aspect of the commutation path, the conversion paths between the outer tube Sa1/Sa2 and the inner tube Sa3/Sa4 are all the same, and the problems of the stray inductance and the voltage peak are less. With the development of wind power systems, the converter circuit of uncontrolled rectifier + boost chopper + PWM inverter has attracted more and more interest of scholars from various countries. In the circuit, the rectifier part adopts a diode uncontrolled rectifier, the boost converter in the middle DC link raises the DC voltage, and the inverter part adopts a PWM three-phase bridge inverter. Compared with back-to-back PWM converters, the topology of the generator-side converter has been simplified, a number of power switch devices and their driving circuits are omitted, the switching loss of the power device is reduced, the cost is reduced, and the reliability of the whole system is enhanced. Combining the advantages mentioned earlier, a topology based on boost three-level converter (BTL converter) and T-type three-level inverter cascaded for wind power generation system is proposed, as shown in Figure 1.  
Since FCS-MPC has an intuitive concept, flexible control, no modulator, no parameter setting, and fast dynamic response, it can also effectively deal with the system of non-linear links and various restrictions and other advantages, so it has become a hot research topic. At present, FCS-MPC has been widely used in various power electronic converters. Compared with proportional integral control, MPC has superior performance and has attracted much attention. First presented in [5], MPC deals with linear and nonlinear models and provides maximum realizable bandwidth.