Multiple reference frame control of permanent magnet synchronous motor with non-sinusoidal back EMF using adaptive notch filter

Abstract

Permanent magnet synchronous motors (PMSMs) are suitable options for high-performance applications due to their potential of high power density and torque smoothness. Nevertheless, there are some factors affecting this feature by producing unwanted pulsating torque. One of the causes of torque ripple is the presence of harmonic components in motor back EMF. This paper has presented a multiple reference frame (MRF) method improving torque characteristic in PMSM regarding nonsinusoidal back EMF. An adaptive notch filter (ANF) was used as a current estimator which can separate needed current components. Optimal current components, obtained from Lagrange multiplier method, were regulated through PI controllers which guaranteed the desired convergence. Cogging torque and rms current minimization were intended, too. Results were investigated through simulations in Matlab/Simulink environment.

Reduction of Torque and Flux Ripples in Space Vector Modulation-Based Direct Torque Control of Asymmetric Permanent Magnet Synchronous Machine

“…From (16), it can be deduced that the electromagnetic torque is composed of a dc term Te0, which is correlated with equal sequence product of flux and current, while the alternative terms of Tes2, Tec2, Tes6, Tec6 oscillate at 2ωs and 6ωs of the fundamental frequency, respectively. These harmonic terms are produced by unequal sequence product as illustrated in (16b) [29], [26], [30]. It should be emphasized that the harmonic components of 4 th , 8 th , and 12 th also exist in the estimated torque [30], which are correlated with different unequal sequence product.…”

“…These harmonic terms are produced by unequal sequence product as illustrated in (16b) [29], [26], [30]. It should be emphasized that the harmonic components of 4 th , 8 th , and 12 th also exist in the estimated torque [30], which are correlated with different unequal sequence product. However, they are neglected compared with the 2 nd and 6 th components.…”

“…MACHINE MODEL CONSIDERING WINDING ASYMMETRY AND INVERTER NONLINEARITY Due to unbalanced back-EMF caused by winding asymmetry and influence of inverter nonlinearity, the stator voltage, current, and flux in a three-phase system can be expressed in terms of their positive-, negative-, zero-sequence components of ωs and the harmonic components of -5ωs and +7ωs [20], [26], [29], [30]. Since the model under investigation is a three-wire connection system, i.e., floating neutral point, the zero-sequence component is neglected [29].…”

“…It is worth mentioning that only the positive-, negative-sequence and harmonic components of fifth and seventh are taken into consideration in this paper. Therefore, the voltage, current, and stator flux linkage vectors can be expressed in the stationary αβ frame as [26], [30] …”

“…From (13), it can be deduced that the negative sequence component due to unbalanced back EMF behalves as the ac oscillation at the frequency of 2ωs in the dqs 1+ reference frame [14], [17]. Whereas, the harmonic components of -5ωs and +7ωs caused by inverter nonlinearity behave as the ac oscillation at the frequency of ±6ωs in the dqs 1+ reference frame [20], [26], [30]. According to Fig.…”