Maximum Torque Per Ampere strategy for a biharmonic five-phase synchronous machine

매입형 영구자석 동기 전동기는 높은 효율과 빠른 동특성, 넓은 정출력 운전 영역 등의 장점 때문에 다양한 산업 분야에서 각광을 받고 있다. 특히 매입형 영구자석 동기기의 단위 전류당 최대 토크(Maximum Torque Per Ampere, MTPA) 운전 방법은 전동기의 최대 효율 운전을 위해서 필수적인 운전방법이 되었다. 이론적인 MTPA 운전점은 전동기의 제 정수에 의해 결정되는데, 매입형 영구자석 동기 전동기는 온도와 운전 영역에 따라 전동기 제 정수의 변화가 심하여 정확한 MTPA 운전을 하기 위해서는 전동기의 전 운전 영역에 대한 전동기 제 정수를 미리 알고 있어야 한다. 본 논문에서는 신호 주입 개념을 도입한 새로운 MTPA 운전 방법을 제안한다. 전류에 높은 주파수의 신호를 주입하여 그 주입된 신호에 의한 반응을 확인함으로 MTPA 운전점을 판별하게 된다. 이 방법은 전동기 제 정수 변동에 강인하며, 간단한 신호처리 과정을 통하여 MTPA 운전을 할 수 있다. Interior Permanent Magnet Synchronous Motor(IPMSM) have gained an increasing popularity in recent years for a variety of industrial applications, because of their high power density, high efficiency and possibility of flux weakening operation. Because the efficiency of IPMSM is one of the important performance characteristic, the Maximum Torque Per Ampere(MTPA) operating method has been indispensible. In theory, MTPA operating point can be calculated using the exact values of the machine parameters. However, the values of the IPMSM parameters are known to vary widely according to the operating condition. Therefore, to operate the IPMSM in the MTPA operating point, the machine parameters should be estimated in real-time. In this paper, the new MTPA operating method based on the signal injection is presented. By injecting the high frequency current signal, the MTPA operating criteria can be calculated by measuring the input power to IPMSM. The proposed method can find the MTPA operating point with simple signal processing regardless of the parameter variation.

In this paper, a modified control strategy of Finite-Control-Set Model Predictive Control (FCS-MPC) for the Interior Permanent Magnet Synchronous Motor (IPMSM) is proposed to solve the problem that the actual stator current cannot quickly track the given Maximum Torque Per Ampere (MTPA) current due to the integration saturation of the current regulator caused by sudden changes in load torque. The FCS-MPC controller is used to replace the PI current regulator, to obtain a more accurate voltage vector and achieve real-time dynamic tracking of the IPMSM MTPA target trajectory. The cost function of FCS-MPC control strategy is designed multi-objective combination to meet such requirements: torque tracking, MTPA current tracking and limitation of the maximum current. The simulation and experimental results show that the proposed control strategy can track the MTPA given current and torque in real time during load torque sudden changes.

The winding of the motor stator coil can be faulted due to high voltage, high temperature stress and etc. In the ITF (Inter Turn Fault) winding, large fault current, ohmic loss, and excessive winding heat are induced. As a result, fault aggravation and machine burning might happen unless adequate fault diagnosis and management are equipped. By limiting the copper loss by the ITF, the faulted motor could operate without aggravation till the adequate fault management action is performed. In this paper, an IPMSM (Interior Permanent Magnet Synchronous Motor) ITF tolerant drive method by limiting internal copper loss is proposed. The copper loss by the ITF is made simple for the proposed method and analyzed with various current, speed, and output torque condition. By maximizing the output torque with minimum IPMSM copper losses, MTPL (Maximum Torque Per Loss) operation point is suggested. Compared with the MTPA (Maximum Torque Per Ampere) the MTPL is more efficient operation point with ITF. To verify the proposed method, experiment studies are performed with an IPMSM with an ITF. The results show the feasibility and practicality of the proposed method.

In this paper, a comprehensive and practical method of implementing speed range extended maximum torque per ampere (MTPA) control for permanent magnet synchronous machine (PMSM) is presented. The inverter-based method of measuring PMSM parameters, including winding resistance and d- and q- axis flux linkages, is introduced. The nonlinearities of the inverter, including voltage amplitude error and voltage phase shift, are identified and compensated, which improves the accuracy of the characterized flux linkage. The extended MTPA current references are obtained by employing nonlinear optimization algorithm, and the results are verified analytically on the current plane. MTPA control is applied on the PMSM experimentally in the entire speed range. Current transition, torque control accuracy, and efficiency performance are measured in the entire torque–speed range.

An improved algorithm for MTPA (Maximum Torque Per Ampere) and Field Weakening operation which is suitable for implementation with Field Oriented Control, has been proposed for the Synchronous Reluctance motor (SynRel) for high dynamic performance. The proposed method overcomes the problem of excessive current flow into the machine while generating the d-axis and q-axis current commands independently. At the same time to operate the inverter in the linear modulation region (0≤m≤1) to minimize the output torque ripple. The proposed method helps to attain MTPA operation below the base speed to operate with the rated load and a fast speed response in Field Weakening mode. The validity and efficacy of the proposed algorithm is verified by simulation in MATLAB and SIMULINK.

This manuscript presents an innovative control strategy for the Hybrid Excitation Permanent Magnet Synchronous Motor (HEPMSM) designed for electric vehicle (EV) applications. The strategy combines Maximum Torque Point Tracking (MTPT) and Maximum Torque Per Ampere (MTPA) techniques to track the ideal torque-speed profile, ensuring maximum torque at low speeds for starting and climbing, and high power at higher speeds for cruising. A novel unidirectional excitation current method is proposed to replace traditional bidirectional field current control, eliminating the risk of permanent magnet demagnetization, reducing copper losses, and increasing efficiency. This approach extends the constant power (CP) region by a 4.2:1 ratio. The manuscript also introduces a detailed mathematical model, considering both iron core losses and their impact on the EV profile. Additionally, the Multi-Objective Ant Lion Optimizer (MOALO) algorithm is used in two stages: first to optimize the hybridization ratio (HR) and base speed (Nb), and second to analyze the effect of varying the hybridization ratio while maintaining constrained output power. The proposed strategy is validated through MATLAB simulations, demonstrating its effectiveness in achieving high acceleration, efficiency, and reliability for EV applications.

Maximum Torque Per Ampere (MTPA) control makes full use of the Interior Permanent Magnet Synchronous Motor(IPMSM), and the current is minimized under the same torque, so that the energy consumption is minimized. In this paper, the formula method is used to directly calculate the current operating point. The direct calculation method relies on motor parameters, In order to solve this problem, this paper combines the least squares one-time algorithm and the recursive algorithm, and adopts the least-squares limited memory method to identify these parameters. So that The current amplitude of the motor is always kept to a minimum.

A compensation algorithm targeting for torque development from a surface mounted permanent magnet synchronous machine (SPMSM) including a low speed operation is presented in this paper. As known, PM flux linkage in SPMSM is varied by temperature. Because a Maximum Torque Per Ampere (MTPA) look up table (LUT), a control algorithm used for minimizing copper losses, is generated using calculated permanent magnet flux linkage, change of permanent magnet flux linkage yields torque error of a SPMSM drive. In the manuscript, estimated permanent magnet flux linkage is obtained using a stator flux observer. The torque error is corrected using the estimated permanent magnet flux linkage. The proposed algorithm is implemented and verified in simulation and experiment

A nonlinear programming optimization algorithmis implemented for the control of a PMSM to find the optimumcurrent vector references which minimize the total copperand core losses in the entire operating region of the motor,including the field weakening mode. The maximum voltage andcurrent constraints of the drive system are also included in theoptimization. The results for an investigated 50 kW PMSMmachinefrom the optimization algorithm is compared withMaximum Torque Per Ampere(MTPA) field oriented vectorcontrol method which inherently takes in to account the copperloss only. It is shown that the efficiency is improved in theentire high-speed operating region of the machine up to 8%.Besides, the machine is simulated in an electric vehicle and itis shown that by using the optimization method instead of theMTPA, the power loss is decreased up to 1.5 % in NEDC drivecycle. Furthermore the loss determination in the equivalentcircuit has been

In this paper, an experimental investigation on the comparison between the Maximum Torque Per Ampere (MTPA) and the Field Orientation Control (FOC) algorithms for interior permanent magnet synchronous machines (IPMSMs) is described, analyzed and discussed. This investigation was carried out on a small-power IPMSM with low saliency ratio. More in detail, after a previous simulation study, the control techniques have been experimentally implemented and validated through means of a dSPACE® rapid prototyping system. The performances of the two algorithms have been evaluated and compared, obtaining interesting results.

In this paper, a linear torque control strategy is first proposed for interior permanent magnet synchronous motor drives to fully utilize the reluctance torque and simplify the controller design. The proposed linear torque control strategy also extends the existing maximum torque per ampere control in the constant torque limit region up to the entire field-weakening region. It is found that in an intermediate speed region, called partial field-weakening region, the existing maximum torque per ampere control can still be applied under lighter load condition. In addition, the proposed control can also achieve the objective of minimum copper loss (i.e., maximum torque per ampere) for the entire speed range. Sound theoretical basis is given in the context. Moreover, an adaptive limiter is proposed for efficiently implementing the proposed control strategy over the entire speed range. Finally, a prototype is also constructed by using a fixed-point DSP TMS320F240 and some experimental results are given to verify the validity of the proposed control strategy.

Newly proposed RG-MADS (Randomly Guided Mesh Adaptive Direct Search) has been applied to the optimal design of Interior Permanent Magnet Synchronous Motor (IPMSM) which has the distinctive features of magnetic saturation. RG-MADS, advanced from classical MADS algorithm, has the superiority in computational time and reliable convergence accuracy to the optimal solution, thus it is appropriate to the optimal design of IPMSM coupled with time-consuming Finite Element Analysis (FEA), necessary to the nonlinear magnetic application for better accuracy. Effectiveness of RG-MADS has been verified through the well-known benchmark-functions beforehand. In addition, the proposed RG-MADS has been applied to the optimal design of IPMSM aiming at maximizing the Maximum Torque Per Ampere (MTPA), which is regarded as representative design goal of IPMSM.

Maximum Torque Per Voltage trajectory has been utilized only during field weakening operation of Interior Permanent Magnet (IPM) motor. In this paper, the voltage minimization control from zero-speed is proposed. Voltage minimization results in maximum torque per voltage control of IPM motor. The control implementation is also simple in comparison to current minimization, as the operation is always along the current-limit locus irrespective of operation in field-weakening. Voltage minimization technique minimizes the core losses whereas current minimization would minimize the copper losses. The mathematical model of IPM motor following voltage minimization is derived and the solution to the 4th order quartic equations is obtained using Ferrari’s method. The solution obtained is utilized to develop a look-up table for vector control of IPM motor. A comparative analysis of voltage minimization and current minimization is established which is supported by simulation results and demonstrated by detailed experimental results.

In this paper, the possibility of designing a five-phase Surface-mounted Permanent Magnet (SPM) machine with 20 slots and 8 poles for a low power marine propulsion system is examined. Due to its particular winding and surface magnet design, the machine inherently offers an electronic pole changing effect from 3×4 pole pairs at low speed to 4 pole pairs at high speed. At high speed, in the constant power range, according to Finite Element Analysis, the Maximum Torque Per Ampere strategy appears not to be the right solution to minimize the whole machine losses (copper, iron and magnets). In particular, a strategy that favors the 4-pole rotating field at high speed allows to mitigate the magnet losses, thus limiting the risk of magnet overheating.

When a permanent-magnet synchronous motor is driven by an electric tractor, potholes, sudden changes in speed and motor temperature rise may occur during transportation and plow operations. These factors may cause the motor operation and control parameters to change. The traditional maximum torque per ampere (MTPA) trajectory is based on the control parameters of the motor and the trajectory cannot be changed as the motor parameters change. However, the actual operation of the drive motor MTPA trajectory will change, which led to control deviation. This paper presents a torque current ratio limit tracking method, the torque in real time to consume the minimum current vector, MTPA trajectory closer to the actual operation of the motor drive MTPA curve, to obtain better maximum torque current ratio trajectory, the motor has More anti-interference. Through Simulink simulation and experimental verification, the improved MTPA algorithm can make the motor run more stable and can adapt to the harsh working environment of the driving motor.