Performance Improvement of Servo Control System Driven by Novel PMSM-DTC Based On Fixed Sector Division Criterion

Abstract

In order to improve the performance of the servo control system driven by a permanent magnet synchronous motor (PMSM) under novel direct torque control (NDTC), which, utilizing composite active vectors, fixed sector division criterion, is proposed in this paper. The precondition of the accurate compensations of torque and flux errors is that the sector where the stator flux linkage is located can be determined accurately. Consequently, the adaptive sector division criterion is adopted in NDTC. However, the computation burden is inevitably increased with the using of the adaptive part. On the other hand, the main errors can be compensated through SV-DTC (DTC-utilizing single active vector), while another active vector applied in NDTC can only supply the auxiliary error compensation. The relationships of the two active vectors' characteristics in NDTC are analyzed in this paper based on the active factor. Furthermore, the fixed sector division criterion is proposed for NDTC (FS-NDTC), which can classify the complexity of the control system. Additionally, the switching table for the selections of the two active vectors is designed. The effectiveness of the proposed FS-NDTC is verified through the experimental results on a 100-W PMSM drive system.

Performance Improvement for PMSM Driven by DTC Based on Discrete Duty Ratio Determination Method

“…In the proposed novel direct torque control (NDTC) scheme in [2], two active vectors are applied in one control period, which can improve the steady-state performance of the control system effectively. Additionally, the fixed sector division criterion is proposed for NDTC (FS-DTC), which can classify the complexity of the control system [3], as shown in Figure 1. It is also shown in Figure 1 that the proposed discrete duty ratio determination method in this paper is used to replace the traditional duty ratio determination method in FS-DTC.…”

“…On the other hand, in order to improve the steady-state performance of the PMSM, the novel direct torque control (NDTC) utilizing composite active vectors has been proposed in [2]. Despite the better steady-state and dynamic-state performance of the PMSM system can be obtained, the computation burden is inevitably increased with the using of the adaptive sector division criterion, therefore, the fixed sector division criterion is proposed for the control system (FS-DTC) in [3]. In order to simplify the complexity of the control system, the determination method of the duty ratio value is studied in this paper.The analytical relationship between the sector angle of the synthetic vector and the error rate is deduced first.…”

“…It is also shown in Figure 1 that the proposed discrete duty ratio determination method in this paper is used to replace the traditional duty ratio determination method in FS-DTC. As the main errors can be compensated by the applied active vector in SV-DTC [2], the applied two active vectors in FS-DTC are classified as master vector and slave vector [3]. Consequently, the active angle of the master vector and the slave active vector in FS-DTC are defined as θ sm and θ ss , respectively, as shown in Figure 2.…”

“…Permanent magnet synchronous motor (PMSM) has lots of merits, including high reliability and good control performance. Additionally, it has been applied in industrial robot application widely [1][2][3][4][5][6][7]. Field-oriented control (FOC) and direct torque control (DTC) are the two widely applied high-performance control strategies for the PMSM [8][9][10][11][12][13].…”

An Improved Torque Control Strategy of PMSM Drive Considering On-Line MTPA Operation

“…A lot of work has been done to improve dynamic torque performance and to optimize the output efficiency of the torque of permanent magnet synchronous motors (PMSMs) in recent years [1][2][3][4][5][6][7][8]. Additionally, various optimal torque control strategies have been proposed, such as direct torque control (DTC) [4,5], predictive torque control [6,7] and nonlinear control strategies [8], etc.…”