Performance assessment of the VSC using two model predictive control schemes

Abstract

Finite control set model predictive control (FCS-MPC) methods in different power electronics application are gaining high attention due to their simplicity and fast dynamics. This paper introduces an experimental assessment of the two-level three-phase voltage source converter (2L-VSC) using two FCS-MPC algorithms. In order to perform such comparative evaluation, the 2L-VSC efficiency and total harmonics distortion voltage (THDv) have been measured where considering a linear load and non-linear load. The new algorithm gives better results than the conventional algorithm in terms of the THD and 2L-VSC efficiency. The results also demonstrate the performance of the system using carrier based pulse width modulation (CB-PWM). These findings have been validated for both linear and non-linear loads through experimental verification on 4 kW 2L-VSC prototype. It can be concluded that a comparable performance is achieved by using the conventional FCS-MPC, Improved FCS-MPC, and CB-PWM algorithms.

Performance Assessment of Grid Forming Converters Using Different Finite Control Set Model Predictive Control (FCS-MPC) Algorithms

“…A prediction horizon N = 1 based on the accurate system model is used to predict the future value of the state variable (V) and feed the measurements back at the Kt instant, as shown in Figure 3a. In this scenario, a single objective CF, which is described mathematically in (15), defines the control system objective. In fact, the state variable V moves toward the reference trajectory V * and is defined as V p .…”

“…Capacitor voltage, as shown in Figure 3a, which is used in this work, can only be regulated indirectly through the inductor current. Therefore, by involving only the capacitor voltage error as given in conventional CF, which is described in (15), will result in a voltage trajectory V p pointing significantly away from the reference trajectory V * . High voltage deviations increase the error between the predicted and the reference voltages resulting in a high THDv.…”

“…The cost function, defined by (15), is evaluated for each sector. Each prediction is evaluated based on (6), where the duty cycles for the two active vectors are calculated by solving the following equation:…”

“…In [14], an improvement of the traditional FCS-MPC presented in [13] has been proposed to provide better power quality. Both algorithms have been assessed up to 4 kW in terms of power quality and losses in [15]. Apparently, there is a lack of information on how both algorithms are classified comparing to the regulated MPC algorithms.…”