A novel PMSM hybrid sensorless control strategy for EV applications based on PLL and HFI

Abstract

Abstract-In this paper, a novel hybrid sensorless control strategy for Permanent Magnet Synchronous Machine (PMSM) drives applied to Electric Vehicles (EV) is presented. This sensorless strategy covers the EV full speed range and also has speed reversal capability. It combines a High Frequency Injection (HFI) technique for low and zero speeds, and a Phase-Locked Loop (PLL) for the medium and high speed regions. A solution to achieve smooth transitions between the PLL and the HFI strategies is also proposed, allowing to correctly detect the rotor position polarity when HFI takes part. Wide speed and torque four-quadrant simulation results are provided, which validate the proposed sensorless strategy for being further implemented in EV.

Sensorless control strategy for light-duty EVs and efficiency loss evaluation of high frequency injection under standardized urban driving cycles

“…, was considered in this study. The following expression was obtained, by operating the resultant estimated back-EMF components according to the structure shown in figure 2 [43]: − e α cos( θ e,P LL ) − e β sin( θ e,P LL ) = w e Ψ P M ∆ e , (10) where, w e is the estimated electrical speed; θ e,P LL is the estimated electrical position; and ∆ e = θ e,P LL − θ e is the angle deviation. The Proportional Integral (PI) controller minimizes this error; consequently, the estimated value θ e,P LL tracks the real electrical angle.…”

“…where, V i is the amplitude of the HF signal that is introduced; and, w i is the angular speed of rotation. The currents that are measured, due to the saliency of the machine, contain the rotor position at w i t [27], which requires a current signal post-processing procedure (figure 1, signal processing block), details of which may be found in [27,28,43]. Three important requirements must be considered for proper adjustment of the HFI-based sensorless controller:…”

“…PLL HFI PLL with HF Hysteresis Hysteresis Threshold to be empirically adjusted (figure 1, speed threshold and transition blocks) [43]. This threshold must be set at a sufficiently low value to ensure that there is enough back-EMF for correct estimation of the position by the observer.…”

“…As this error value might be unacceptable (if it reversed the polarity of the torque), the integration of the HFI technique in the control algorithm requires a procedure that will permit a smooth transition between the HFI and the PLL algorithms. In this context, the authors proposed a procedure in [43], the operating principle of which is illustrated in figure 3.…”

Sensorless Control of Permanent Magnet Synchronous Machine with Magnetic Saliency Tracking Based on Voltage Signal Injection

“…In the literature, a plethora of PMSM sensorless approaches have been proposed that could be mainly classified into two strategies: the fundamental excitation and saliency and signal injection [3][4][5][6][7]. The first strategy has been established based on the state observer methodology using only measurements of fundamental excitation variables such as stator voltages and currents.…”