On-line tracking of the MTPA trajectory in IPM motors via active power measurement

Abstract

The real-time tracking of the Maximum-Torque-Per-Ampere (MTPA) trajectory in Interior-Permanent-Magnet (IPM) motors is addressed in this paper. The considered approach is based on the injection of proper current test signals and aims at minimizing torque oscillations at the injected frequency, this last condition assuring MTPA operations. Differently from previous approaches motor active power is monitored to detect the out-of-MTPA condition (i.e. torque oscillations), instead of measured motor speed, thus avoiding the use of high-resolution speed transducers, as required by previous approaches. Analytical development are provided, as well as simulation and experimental results, proving the effectiveness of the proposal.

A novel approach to torque estimation in IPM synchronous motor drives

“…: Another way to describe the MTPA condition is obtained by applying (8) to (2), which leads to: (9) An explicit expression of the MTPA condition as function of the unknown parameters is obtained by substituting (4), (5) and (9) into (6):…”

“…The common dis advantages of model based techniques are the computational load and the heavy assumptions, particularly on the knowledge of motor parameters. A smart alternative is represented by the signal injection techniques, which have recently brought fair results, due to their independence from the system mode\, such as [5] and [6]. On the other hand, while injection-based MTPA algorithms disregard motor parameters, the torque estimation does not, and the availability of both features in the same drive is still an open issue.…”

EMF-based position sensorless control of IPMSM with improved current vector control strategy

“…Some papers combined the online parameter identification with MTPA control. But the online accurate identification of all parameters is difficult and makes the control algorithm complex [11]. Another commonly used MTPA control method is the off-line test method.…”

A power perturbation-based MTPA control with disturbance torque observer for IPMSM drive system

“…Therefore, an appropriate control method is required in order to utilize the advantage of the reluctance torque in the constant torque and constant power region. Recently, some maximum torque per ampere (MTPA) control methodologies have been proposed to improve the torque output in the constant torque region for the IPMSMs (Ahmed et al, 2014; Antonello et al, 2014; Bolognani et al, 2010, 2011; Kim et al, 2013; Lin et al, 2014; Sun and Wang, 2015; Sun et al, 2015). These results can be divided into three groups (Kim et al, 2013): 1) MTPA point calculation based on machine parameters; 2) minimum current operation using searching algorithms; and 3) MTPA point tracking with an additional signal injection.…”

“…Moreover, low torque control accuracy under the influence of torque disturbance and harmonics is exhibited (Ahmed et al, 2014). In the last group, the signal injection control schemes can be classified as detecting torque variation from speed variation (Antonello et al, 2014; Bolognani et al, 2011), detecting torque variation from machine power variation (Bolognani et al, 2010; Kim et al, 2013) and detecting torque variation from current angle (Sun and Wang, 2015; Sun et al, 2015). In addition, the third scheme utilizes the variation of the angle between the stator current and the q -axis to achieve MTPA control by injection signal into the motor.…”