A Novel Optimal Current Trajectory Control Strategy of IPMSM Considering the Cross Saturation Effects

Abstract

Abstract:The nonlinearity and uncertain variation of machine parameters are always caused by cross coupling and magnetic saturation effects, which are easily neglected in the conventional control strategy. In this paper, a current trajectory control strategy (CTCS) is proposed to take the cross coupling and magnetic saturation effects into account under voltage and current constraints. It can be considered as a calculating method considering parameter variation and separating among each iteration step which treats the calculated result of the former step as the initial value of the next step. At first, the torque command is translated into the current reference. Then, the increments between the target value and real value of the torque and the voltage are respectively calculated, which are subsequently converted into the current modification vector in di d , di q framework for further analysis. In order to take the influence caused by cross coupling and magnetic saturation effects on the CTCS into consideration, self and mutual inductances are analyzed by finite element analysis (FEA). The results of the simulation and experiment show that the rapid response and robustness on reference speed variation could be achieved by employing the proposed CTCS, and the seamless switching between the constant torque and flux-weakening operation can also be realized.

Nonlinear Magnetic Model of IPMSM Based on the Frozen Permeability Technique Utilized in Improved MTPA Control

“…This also directly refers to the flux linkage components of IPMSM used in Equations ( 1)-(3). Conventional magnetic models use an unambiguous separation of the excitation components of the flux linkages [21][22][23]. In this way, the superposition method is employed in a nonlinear system, which undoubtedly leads to inaccurate magnetic models.…”

“…The IPMSM's overall torque is produced by the simultaneous existence of the electromagnetic and reluctance torque components due to the rotor circuit saliency. In order to utilize these advantage, maximum torque strategies and loss minimization control are regularly utilized for high performance EV drive applications, generating optimal control variables to attain the desired performances [8,23,28,29].…”

Sensorless PMSM Drive Implementation by Introduction of Maximum Efficiency Characteristics in Reference Current Generation

“…The simplest zero d-axis current reference control (i dr = 0) is still employed in applications with surface mounted PMSMs [21], which exhibit similar values of d-and q-axis inductances. Although it is generally applicable, the maximum torque per ampere (MTPA) characteristic [10,15,[19][20][21][22][23][24][25][26][27], which considers PMSM copper losses, is usually used for generation of current references in drives with interior PMSM, which exhibit different values of dand q-axis inductances and thus produce a significant reluctance torque component in addition to the permanent magnet torque component. When MTPA is applied, the PMSM drive produces maximum torque per unit of stator current but cannot reach the maximum efficiency due to the neglected iron core losses.…”

“…When MTPA is applied, the PMSM drive produces maximum torque per unit of stator current but cannot reach the maximum efficiency due to the neglected iron core losses. The maximum efficiency (ME) characteristic [21,[23][24][25][26][27][28] considers copper losses as well as iron core losses of PMSM. When it is applied for generation of current references, the maximum efficiency of a PMSM drive can be achieved.…”

Prediction Error Analysis of Finite-Control-Set Model Predictive Current Control for IPMSMs

“…The interior permanent magnet synchronous motor (IPMSM) is widely applied in many industry applications due to its high power intensity, high efficiency, high toque density, and wide speed range [1]. As an important control objective, the current of IPMSM is usually adjusted by utilizing vector control (VC) schemes based on proportional-integral (PI) controllers and pulse-width-modulation (PWM) strategies [2].…”