Model Predictive Direct Torque Control for SPMSM With Load Angle Limitation

Abstract

Abstract-The purpose of this paper is to describe a model predictive direct torque control (MPDTC) with load angle limitation for surface-mounted permanent magnet synchronous motor (SPMSM) drive system. In this paper, an exact discrete-time state-space model of SPMSM is presented, which improves the state prediction accuracy comparing to simple Euler approximation. A finite control set type MPDTC is used to select the optimum voltage vectors applying to the voltage source inverter (VSI). It makes full use of the inherent discrete nature of VSI, and according to the predefined cost function it chooses the optimal solution from the possible switching states. It has been found that with the proposed scheme SPMSM drives show adequate dynamic torque performance and considerable torque ripple reduction as compared to traditional direct torque control (t-DTC). With the load angle limitation in the cost function, the proposed scheme can prevent the PMSMs falling from synchronism.

Runge-Kutta Model Predictive Speed Control for Permanent Magnet Synchronous Motors

“…In their other application, a robust cascaded nonlinear predictive controller with anti-windup compensator [8] has been proposed for speed control. In [9], a model predictive direct torque control technique with load angle limitation for surface-mounted PMSM (SMPMSM) has been proposed. A cascaded adaptive explicit model predictive controller has been proposed for torque control without sensors to provide high dynamic performance for PMSM drivers [10].…”

Torque Ripple Minimization of Matrix Converter-Fed PMSM Drives Using Advanced Direct Torque Control

“…The MPC algorithm finds the sequence of optimal input u(k) that satisfies given constraints [22]. From that sequence of optimal input u(k), only the first input is applied to plant for next sampling interval.…”

“…So input currents are computed with (20) in order to compute the angle between input current vector and input voltage vector if the configuration n is applied (φ in ). Then a third term is added in (21) to take into account input power factor and in order to make it as close to unity as possible (22). In (22) c is a weighting factor.…”

“…Then each of the eight possible switching positions (22) 63 is to be further branched to next eight possible positions. But using the branch and bound algorithm, if any switching position at first level is found to be unfeasible, it is not branched i.e.it has reached the allowable bound so that node will not be further branched.…”

“…The PMSM can be modelled with the help of state space equations in the dq rotor frame (10) where I d , I q and V d , V q are stator currents and voltages expressed in the dq frame, R and L are the stator winding resistor and inductance respectively, ω is the rotor angular speed and φ is the flux produced by permanent magnets [22].…”