Maximum Torque Per Ampere Control Research Articles

The Research on Interior Permanent Magnetic Synchronous Motor MTPA Control

The research on maximum-torque-per-ampere (MTPA) control of Interior Permanent Magnetic Synchronous Motor (IPMSM) is presented in this paper. Based on the IPMSM mathematical model in d-q reference frame, the equations of d, q axis currents and magnetic torque were derived by using extreme value principle. Thus, this algorithm realizes the IPMSM MTPA control. Under the condition of same magnetic torque, the IPMSM MTPA control can minimize the input current magnitude, decrease the IPMSM power loss and the inverter capacity, increase the system efficiency and improve the dynamic performance of system. At last, the paper built simulation model and verified the MTPA algorithm above is correct.

Sensorless IPMSM Drive System Using Saliency Back-EMF-Based Intelligent Torque Observer With MTPA Control

A saliency back-electromotive force (EMF)-based wavelet fuzzy neural network (WFNN) torque observer using a new maximum torque per ampere (MTPA) control is proposed in this study to improve the speed estimating performance of a sensorless interior permanent magnet synchronous motor (IPMSM) drive system. First, the characteristics and mathematical model of the saliency back-EMF-based proportional-integral-derivative (PID) torque observer with the mechanical model-based phase-lock-loop (PLL) for the estimation of the rotor flux angle and speed of the IPMSM are discussed. Then, a new saliency back-EMF-based MTPA control suitable for the implementation using digital signal processor (DSP) is introduced. Moreover, the saliency back-EMF-based rotor flux angle and speed estimation method using WFNN torque observer is proposed. Furthermore, detailed network structure and online learning algorithms of WFNN are described. Finally, the feasibility of the proposed control schemes is verified through experimental results.

High Performance and Reliable Torque Control of Permanent Magnet Synchronous Motors in Electric Vehicle Applications

This paper presents a novel, high performance maximum torque per ampere control (MTPAC) of an interior permanent magnet synchronous motor (IPMSM) that is chosen for a vehicular application. In vehicular applications IPMSMs are usually controlled with MTPAC method due to fully utilization of reluctance torque, usually with this method maximum torque per ampere trajectories are obtained by look up tables because of nonlinear relation between torque and current; however, utilization of look up tables decreases the real time performance and reliability of the system. Some studies have been used MTPAC with nonlinear equations between d-q axes currents and torque; however, controller calculation burden can be reduced with proposed method. In this study relationship between torque and stator current magnitude is obtained as a first order linear equation with curve fitting. Thereby it has been possible to work with only one linear torque equation instead of nonlinear equations, therefore controller performance and reliability is increased. Control of the motor is simulated under different load conditions, and results are given and analysed.DOI: http://dx.doi.org/10.5755/j01.eee.19.7.2159

High Performance and Reliable Torque Control of Permanent Magnet Synchronous Motors in Electric Vehicle Applications

This paper presents a novel, high performance maximum torque per ampere control (MTPAC) of an interior permanent magnet synchronous motor (IPMSM) that is chosen for a vehicular application. In vehicular applications IPMSMs are usually controlled with MTPAC method due to fully utilization of reluctance torque, usually with this method maximum torque per ampere trajectories are obtained by look up tables because of nonlinear relation between torque and current; however, utilization of look up tables decreases the real time performance and reliability of the system. Some studies have been used MTPAC with nonlinear equations between d-q axes currents and torque; however, controller calculation burden can be reduced with proposed method. In this study relationship between torque and stator current magnitude is obtained as a first order linear equation with curve fitting. Thereby it has been possible to work with only one linear torque equation instead of nonlinear equations, therefore controller performance and reliability is increased. Control of the motor is simulated under different load conditions, and results are given and analysed.DOI: http://dx.doi.org/10.5755/j01.eee.19.7.2159

Position sensorless control of IPMSMs based on a novel flux model suitable for maximum torque control

AbstractIn this paper, a novel position sensorless control method for interior permanent magnet synchronous motors (IPMSMs) that is based on a novel flux model suitable for maximum torque control has been proposed. Maximum torque per ampere (MTPA) control is often utilized for driving IPMSMs with the maximum efficiency. In order to implement this control, generally, the accurate motor parameters are required. However, the inductance varies dramatically because of magnetic saturation, which has been one of the most important problems in recent years. Therefore, the conventional MTPA control method fails to achieve maximum efficiency for IPMSMs because of parameter mismatches. In this paper, first, a novel flux model has been proposed for realizing the position sensorless control of IPMSMs, which is insensitive to Lq. In addition, in this paper it is shown that the proposed flux model can approximately estimate the maximum torque control (MTC) frame, which is a new coordinate aligned with the current vector for MTPA control. Next, in this paper, a precise estimation method for the MTC frame has been proposed. By this method, highly accurate maximum torque control can be achieved. A decoupling control algorithm based on the proposed model is also addressed in this paper. Finally, some experimental results demonstrate the feasibility and effectiveness of the proposed method. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 184(3): 55–66, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22380

最大トルク制御に適した磁束モデルの提案とこれに基づくIPMSMの位置センサレス制御

In this paper, a novel position sensorless control method for interior permanent magnet synchronous motors (IPMSMs) that is based on a novel flux model suitable for maximum torque control has been proposed. Maximum torque per ampere (MTPA) control is often utilized for driving IPMSMs with the maximum efficiency. In order to implement this control, generally, the accurate motor parameters are required. However, the inductance varies dramatically because of magnetic saturation, which has been one of the most important problems in recent years. Therefore, the conventional MTPA control method fails to achieve maximum efficiency for IPMSMs because of parameter mismatches. In this paper, first, a novel flux model has been proposed for realizing the position sensorless control of IPMSMs, which is insensitive to Lq. In addition, in this paper it is shown that the proposed flux model can approximately estimate the maximum torque control (MTC) frame, which is a new coordinate aligned with the current vector for MTPA control. Next, in this paper, a precise estimation method for the MTC frame has been proposed. By this method, highly accurate maximum torque control can be achieved. A decoupling control algorithm based on the proposed model is also addressed in this paper. Finally, some experimental results demonstrate the feasibility and effectiveness of the proposed method. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 184(3): 55–66, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22380

Steady-State and Transient Operation of IPMSMs Under Maximum-Torque-per-Ampere Control

This paper analyzes different aspects of the maximum-torque-per-ampere (MTPA) vector control of interior permanent-magnet synchronous motors at steady state and transient. Two different implementations are considered: a nonlinear-model-based MTPA profile including saturation and cross-saturation effects and a technique based on the maximization of the motor input power versus stator current. Furthermore, this paper analyzes the torque evolution during a transient under an MTPA control strategy on motors with different characteristics. Useful modifications of the current loop are suggested to improve the drive performance. The effects of the torque transient on the sensorless rotor position estimation are also taken into consideration, in case a sensorless MTPA implementation is required. Experimental results confirm the theoretical analysis, showing the benefits of the new control schemes.

Voltage-Constraint-Tracking-Based Field-Weakening Control of IPM Synchronous Motor Drives

In this paper, first, the effect of the interior permanent-magnet synchronous-motor (IPMSM) stator resistance to the maximum available motoring or regenerative braking torque is clarified. Then, a drive operating point is interpreted geometrically as the intersecting point of the torque-demand curve with either the maximum torque per ampere (MTPA) trajectory or the voltage-constraint curve inherently imposed by the motor and inverter under different control modes. Based on this principle, a novel voltage-constraint-tracking (VCT) field-weakening control scheme for IPMSM drives is proposed. The proposed method can automatically determine the desired MTPA or field-weakening control modes and provide a smooth transition between these two modes. No machine parameters are required in the field-weakening control mode, and no dc-link voltage sensor is used, rendering the proposed scheme rather robust. In addition, the minimum copper-loss operation can be preserved in the VCT-based control to achieve high efficiency. The proposed control method has a simple structure so that it can easily be implemented by modifying a conventional vector-controlled drive system for practical applications. Finally, a DSP-based prototype drive is constructed to verify the feasibility of the proposed scheme, and some experimental results are provided to demonstrate the satisfactory features.

Robust Maximum Torque per Ampere (MTPA) Control of PM-Assisted SynRM for Traction Applications

Recently, permanent-magnet-assisted (PMa) synchronous reluctance motors (SynRMs) have been introduced as a possible traction motor in hybrid electric vehicle applications. In order to achieve maximum torque per ampere (MTPA), knowledge of the motor parameters is necessary. Due to the high ambient temperature inside the engine cavity as well as the saturation effect, variation of motor parameters such as inductances and permanent magnet (PM) flux density is not avoidable. Offline models for estimating the motor parameters are known as a computationally intensive method, particularly, when the effect of cross saturation and PM flux deterioration are included. In this paper, a practical MTPA control scheme, along with a simple parameter estimator for the PMa SynRM, is introduced. This method is capable of maintaining the MTPA condition and stays robust against motor parameter variations. To verify the validity and feasibility of the proposed controller, several simulations and experiments results on a low-power laboratory prototype PMa SynRM have been presented.

Position Sensorless Vector Control for Permanent Magnet Synchronous Motors Based on Maximum Torque Control Frame

High efficiency drive can be achieved by the maximum torque-per-ampere (MTPA) control which used reluctance torque effectively. However, the calculations for estimating rotor position and for controlling the d-axis current are required. The motor parameters of inductance etc. that are easily affected by magnetic saturation are included in those calculations. This paper proposes a new MTPA control method, which is robust against changes of motor parameters caused by magnetic saturation. In addition, complex calculation for d-axis current or reference to the table is not necessary. In this method, we define a novel coordinate frame, which has one axis aligned with the current vector of the MTPA control, and estimate the frame directly. Because the parameter Lqm for estimating the frame is less affected by the magnetic saturation than the conventional Lq, the effect of magnetic saturation on the position estimation can be greatly suppressed. First, an extended electromotive force model based on the proposed frame and a parameter Lqm for an estimation of the frame are derived. Next, the effectiveness of this proposed method is confirmed by simulations and experiments.