Sensorless control of PMSM in a ultra high speed region taking iron loss into account

Abstract

The importance of ultra high speed (≥ 50 krpm) motor technology has surfaced for various applications including turbo-compounding system, engines, and air blowers. However, there are challenging issues in a high speed motor technology: 1) robust mechanical structure, 2) materials like low loss silicon steel and high tensile strength, and 3) control issues such as the PWM delay, the PWM distortion, and the iron loss. Especially, the iron loss is usually neglected in the general permanent magnet synchronous motor (PMSM) control. Aside from the motor efficiency, the iron loss alters the PMSM dynamic model. Since the iron loss is not reflected in the conventional sensorless methods, the angle error grows steadily as the speed increases to an extremely high region. In this paper, a sensorless control method considering the iron loss is proposed. It cures the angle error in a high speed region, and the performances are demonstrated through simulation and experimental results.

Compensation of Periodic Magnetic Saturation Effects for the High-Speed Sensorless Control of PMSM Driven by Inverter Output Power Control-based PFC Strategy

“…By transforming (8) into the hypothetical rotating reference frame, which is the γ-δ reference frame presented in [11], the voltage equation of the PMSM can be expressed as follows:…”

“…Equation (10) shows that the back-EMFs in the γ-δ reference frame are DC signals and contain the position error Δθ; thus, the rotor speed and PMSM position can be estimated from the back-EMFs. When using the rotating reference frame model-based back-EMF estimator, the phase lagging between the actual and estimated back-EMFs becomes negligible at steady-states; thus, the rotating reference frame model of PMSM is often preferred for the high-speed sensorless control [11]. The drawback of the rotating reference frame model-based back-EMF estimator is that the estimated speed is used for estimating back-EMFs; thus, the performance of the back-EMF estimator can be degraded by the estimated speed error, particularly at low speeds.…”

A novel initial rotor position alignment method for permanent magnetsynchronous motor using incremental encoder

“…Therefore, several techniques have been proposed by researchers to calculate the initial rotor position without using any sensor. Applying a high frequency signal to motor phases [2][3][4][5][6], saturating the stator magnetic core [7][8][9][10][11], and utilizing the inductance variation according to the rotor position are some of the techniques proposed in the literature [12][13][14]. Although sensorless control methods are advantageous in many respects such as cost, weight, volume, and design complexity [2], the position sensor must still be used to provide high-resolution positional accuracy if the application requires positional control.…”