Robust initial rotor position estimation of permanent magnet brushless AC machines with carrier signal injection-based sensorless control

Abstract

In sensorless control of permanent magnet brushless AC machines, it is necessary to identify the initial rotor position prior to start-up the machine. Although saliency tracking based sensorless techniques are proven to be a good candidate to estimate the initial rotor position in sensorless control, magnetic polarity identification is another important issue. Since the machine saliency undergoes two cycles in single electrical period, the estimated position information based on machine saliency has an angle ambiguity of π. With the aid of magnetic saturation effect, this paper proposes a robust initial rotor position estimation scheme, which utilizes both d-and q-axis carrier current, instead of only q-axis carrier current in conventional pulsating carrier signal injection based sensorless control algorithm. Finally, the experimental results confirm the effectiveness and robustness of the proposed method.Index Terms --Carrier signal injection, initial rotor position, permanent magnet machine, sensorless.

A new signal injection‐based method for estimation of position in interior permanent magnet synchronous motors

“…For this reason, we consider in this study IPMSMs. In the last two decades, signal injection‐based approaches have been successfully applied, in a heuristic manner, in various applications, some of them reported in application journals [10–12, 14, 17, 18]. The classical approach is, first, to inject high‐frequency probing signals into the motor terminal; then, extract the high‐frequency components of the stator currents to get position estimates.…”

A Study on Accurate Initial Rotor Position Offset Detection for a Permanent Magnet Synchronous Motor Under a No-Load Condition

“…Since it is a no-load environment and the speed fluctuation The d-and q-axis voltage equations under the two-speed bidirectional method is summarized are as shown in Equations ( 12), ( 13), (14), and (15).…”

“…In the case of high-frequency injection, however, signal processing such as DFT, BPF, or LPF is required to remove the high-frequency component of the current caused by a specific high-frequency signal to be injected. In the SPMSM or a motor with low salient polarity, the difference in inductance is not significant, so the highfrequency injection method's accuracy may decrease [14][15][16][17][18]. Moreover, when it is necessary to detect the resolver offset in a no-load state, such as mass production, the rotor may move slightly, and the precision may decrease.…”

Speed Sensorless Control of a Surface-mounted Permanent Magnet Drive

“…Speed is generally estimated from back emf [5][6][7][8], but at low speeds the back emf tends to zero, so a different estimation method is required. Two inductance-based effects may be used to identify angular position: saliency and partial saturation of the magnetising flux path [5][6][7][8][9][10][11][12][13][14][15]. Both techniques are suitable for IPM machines, where the rotor interior magnets increase the reluctance of the direct-axis compared with the quadrature axis, and the airgap distance can be small, with more likelihood of saturation.…”

“…These rotor designs, shown in Fig 1 , give sufficient saliency for signal injection methods to be viable at low speeds. The injected signal may be a pulse [9][10][11], or a pulsating or rotating high frequency sinusoid [12][13][14][15]. In this research, pulsed signals were not considered, since they need high bandwidth sensing and data acquisition.…”