Predictive control of three-phase inverter

Predictive Control of Variable Speed Wind Energy Conversion System with Multi Objective Criterions

“…To describe the inverter output voltages, the concept of complex space vector is applied [16][17][18][19]. For a two level voltage source inverter feeding a symmetrical three-phase grid connected system given in Fig.…”

“…By using these switching functions the grid space voltage vector can be expressed as [16][17][18][19]: Also, the inverter output voltage is related to DC link voltage by:…”

“…6, where for each rotor voltage vector the cost function C is evaluated and the optimal voltage vector is then applied during the next sampling period [17][18][19]. (18 …”

“…One of the most benefits of finite states predictive control is its flexibility since we can add nonlinear constraints which are usually difficult to consider in linear controllers by adding more terms in the cost function to be minimised [17][18][19]. Here a third term that takes into account the reduction of the switching frequency without degradation of the reference tracking performance is added to the objective function of (25) by:…”

“…For the selection of the appropriate switching state to be applied to the system a quality function must be defined. The cost function is then evaluated for the predicted values on each sampling interval and the optimal switching state that minimizes the quality function is selected to apply during the next sampling interval [17][18][19].…”