Variable Speed Operation of Brushless Doubly Fed Reluctance Machine Drive Using Model Predictive Current Control Technique
Karuna Kiran, Sukanta Das
Abstract
To accomplish an accurate and fast drive control, model predictive control (MPC) is considered as an effective control strategy nowadays. In MPC, the voltage vectors required for inverter control are evaluated considering the control objectives defined in terms of current or power or torque and flux. The optimal one is selected using an iterative prediction loop and applied in the next control interval. This form of MPC is simple in implementation and shows appreciable dynamic performance but the steady-state performance is compromised due to the limited availability of the number of voltage vectors, especially in the case of a two-level voltage source inverter. The present article explores the viability of the MPC approach for a new candidate such as a brushless doubly fed reluctance machine drive considering its secondary current as the control variable. Moreover, to tackle the steady-state inferiority issue, the duty-cycle control concept is inducted. In comparison to field-oriented control (FOC), the proposed scheme offers a straightforward solution for current control by replacing the inner current proportional-integral controllers and pulsewidth modulator with an optimization-based model predictive current controller. An extensive simulation study in MATLAB, vis-à-vis comparison with FOC scheme, and experimental validations justify the claims of the proposed work.