Compensation for Rotor Position Estimation Error due to Cross-Coupling Magnetic Saturation in Signal Injection Based Sensorless Control of PM Brushless AC Motors

Abstract

Abstract-This paper proposes a simple method for reducing it was established in [7] [8] that the error was caused by the the rotor position estimation error caused by cross-coupling effect of cross-coupling magnetic saturation between the d-and magnetic saturation between the d-and q-axes when signal q-axes, (i.e., Ldqh#O), and was influenced by the machine injection based sensorless control is applied to a brushless AC (BLAC) motor. The error in the estimated rotor position, which design, but, as yet, no measures, from the control aspect, have results when conventional signal injection sensorless control is been proposed to reduce the error. Nevertheless, it is well employed, is analyzed. Based on an improved model of a BLAC known that a mutual inductance exists between the d-and qmotor which accounts for the influence of dq-axis cross-coupling axes of a BLAC motor (Ldqh) as a result of cross-coupling due to on the high-frequency components of the incremental winding magnetic saturation, as shown in [9], both experimentally and inductances, as deduced by either finite element analysis or from by finite element analysis. However, for simplicity, the

Online cross-coupling and self incremental inductances determination of salient permanent magnet synchronous machines

“…The results are obtained using Matlab/Simulink block set models. The speed of the machine is set to 600 rpm and its parameters are shown in Table. 1 The compensation of the position error requires determination of the cross-coupling (mutual) inductance Ldq as well as the self incremental inductances Ld, Lq , or pre-determining the position error at different loads [2]. However, both ideas need pre-commissioning experiments to be able to provide adequate information to the position estimator.…”

“…In addition the obtained data should be stored to be used during the estimation process, which affects the dynamic of the compensator. Based on the previous analysis and the equations produced by [2,4], it is possible to determine mathematically the required inductances by performing simple measurements of the resultant carrier current at different operating conditions. Assuming first that the machine is operating at no load, the normal current equation with no cross-saturation interference is presented in (2).…”

“…Equation (2) is valid at no-load condition [6]. However, by applying heavy load misalignment between the actual rotor and the anisotropy position occurs [2]. This can be due to the rise of cross-coupling inductance Ldq in the carrier current (3).…”

“…This reduces the effectiveness of sensorless control. Saturation and cross-coupling inductance effects are found to be a reason for the saliency/anisotropy misalignment in Permanent Magnet Synchronous Machines (PMSM) [1,2,4]. The phase error between the rotor and the anisotropy position appears in the negative sequence of the carrier current and is related to the self and cross-coupling incremental inductances.…”

“…Thus, in both cases it is essential that the rotor and anisotropy positions are synchronised. Under load conditions it has been theoretically analysed [1,2] and shown experimentally [3] that misalignment occurs between the rotor and anisotropy positions. This reduces the effectiveness of sensorless control.…”