PWM Switching Frequency Signal Injection Sensorless Method in IPMSM

Abstract

The rotor position of an interior permanent-magnet synchronous machine (IPMSM) can be estimated without a position sensor by signal injection sensorless control at standstill and/or in very low speed rotating condition. In the signal injection sensorless control, however, the fundamental control performance is limited by the frequency of the injected signal, and no negligible acoustic noise is generated. If the frequency of the injected voltage signal would increase to pulsewidth modulation (PWM) switching frequency and if the switching frequency is near or above audible range, the dynamics of the sensorless control can be improved, and the acoustic noise can be remarkably reduced or totally eliminated. This paper describes how to extract the rotor position information of IPMSM using the voltage signal injection whose frequency is the same as the PWM switching frequency. Compared to the conventional heterodyning process, the proposed method is simple to implement and appropriate for PWM switching frequency signal injection. The high-frequency voltage signal can be injected in the stationary reference frame or in the estimated rotor reference frame. In this paper, the 5-and 16-kHz signal injections are proposed, implemented, and compared. The experimental results confirm the effectiveness of the proposed method.

A Novel High Frequency Signal Injection Strategy for Self-Sensing Control of Electric AC Machine Drives

“…In this section, the HF voltage and flux-current IPMSM models [8] are presented in stator and rotor reference frames.…”

“…Numerous heterodyning process have been proposed in the literature [8], in this paper, a new demodulation process is proposed, in addition to its control performance and simplicity of the implementation [14], this method improves the rotor position and speed estimation process. Fig.…”

Comparative Evaluation of a Permanent Magnet Machine Saliency-Based Drive with Sine-Wave and Square-Wave Voltage Injection

“…For a rotating sine-wave voltage injection, these saliency harmonics can be decoupled with knowledge of harmonic magnitudes and phases [32]. However, dead-time harmonics in the saliency greatly increase when a rotating voltage is superimposed [33]. More importantly, these dead-time harmonics are usually higher than the harmonics caused by flux saturation [34].…”

A Back-EMF Estimation Error Compensation Method for Accurate Rotor Position Estimation of Surface Mounted Permanent Magnet Synchronous Motors

“…Generally, a PMSM performs vector control based on current control, and rotor position information is essential to perform vector control, however, the encoders and resolvers used to acquire the position information of the rotor are not used because they increase system cost, volume, mechanical attachment and impair system reliability. Among the various applications, sensorless control is preferred for fan and pump products [1][2][3], and for this reason, sensorless methods for driving PMSMs are an active research topic [3][4][5][6][7][8][9][10]. The sensorless methods can be roughly divided into back electromotive force (back-EMF) estimation-based methods [3][4][5][6][7][8] and methods based on inductance changes according to the rotor position [9,10].…”

“…Among the various applications, sensorless control is preferred for fan and pump products [1][2][3], and for this reason, sensorless methods for driving PMSMs are an active research topic [3][4][5][6][7][8][9][10]. The sensorless methods can be roughly divided into back electromotive force (back-EMF) estimation-based methods [3][4][5][6][7][8] and methods based on inductance changes according to the rotor position [9,10]. generally, the back-EMF based methods estimate the back-EMF using the stator voltages and motor currents without requiring any additional high frequency signal injection and the inductance-based methods estimate the inductance value through an external signal injection.…”