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This article proposes a continuum-sensitivity-based method to obtain the optimal design for an interior permanent magnet synchronous motor (IPMSM). Compared with the finite difference method, the continuum sensitivity analysis shortens the computation time significantly when there are numerous design variables. We combine the continuum sensitivity with the shape constraint so that both the shape and the size can be optimized simultaneously and within a short time. This proposed design optimization method is applied to IPMSM rotor design, and its feasibility is verified. The proposed method is expected to be effective for various design problems that require the shape and the size to be optimized simultaneously. [ABSTRACT FROM AUTHOR]

In this paper, a novel initial rotor position estimation method for reliable start-up of the IPMSM is presented. The proposed method combines the improved high frequency pulse signal injection with positive and negative d -axis current bias injection. Differing from the conventional initial rotor position detection scheme, the injection and the field-oriented control periods are separated in the proposed method. Therefore, the filters are not needed in the process of high-frequency response current and fundamental current extraction. The magnet polarity can be estimated by exciting the positive and negative d -axis currents. Afterwards, the peak values of d -axis current during the voltage injection period are accumulated to detect the rotor magnetic polarity. The proposed method can improve the reliability of the magnet polarity detection. Moreover, it is suitable for both the standstill rotor application and the free-running rotor application. The effectiveness of the proposed method is verified on a 1.5 kW IPMSM drive platform. • A reliable initial rotor position detection method for sensorless control of the IPMSM is presented. • No filters are needed for extracting the fundamental currents and the induced currents. • The proposed method can improve the reliability of magnet polarity detection. • The proposed method is suitable for standstill rotor application and free-running rotor application. [ABSTRACT FROM AUTHOR]

As the traditional flux-weakening control strategies have some limitations, such as poor parameter robustness, non-ideal dynamic performance in the constant power region and so on, a new control strategy based on the formula-based feedforward control and the voltage feedback control is proposed. In this strategy, the given reference values of the flux-weakening currents are first calculated by the simplified formulas used in feedforward control, improving the processing speed of the controller by reducing the computational complexity. Then the reference value of the d axis current is compensated by the fuzzy-PI feedback controller, avoiding operating point drifts caused by the change or inaccurate of parameters in the actual. On this basis, a switching strategy is proposed to achieve a smooth switching between the constant torque and the constant power operation region. The experimental results show that the proposed control strategy has excellent performances, such as strong robustness to parameter perturbation, ideal dynamic performance in the flux-weakening region, smooth switching between the operation regions and so on. [ABSTRACT FROM AUTHOR]

This paper proposes a mutual calibration strategy for multiple current sensors in an electric vehicle motor drive. The motor drive usually consists of three current sensors, i.e., a dc-bus current sensor and two phase current sensors. Due to the aging effect and harsh operating environment, the accuracy uncertainty issue is inevitable in these crucial sensors, which results in poor driving performance. In this paper, the detection voltage injection (DV-Injection) method is proposed for mutual calibration of the aforementioned current sensors. Two opposite basic vectors are set together to detect and eliminate the offset error of the dc-bus current sensor. Then, both the directly measured phase-current values by the phase-current sensors and the indirectly measured values by the dc-bus current sensor are sampled. These values are utilized for mutual calibration of the phase-current sensor offset errors and scaling error differences among all the current sensors. Meanwhile, the DV-Injection process is only applied in the period of calibration process, whereas in the remaining intervals the space vector pulsewidth modulation technology is utilized. Finally, the effectiveness of the proposed scheme is verified by simulation study in MATLAB/Simulink and experimental results on a 5-kW interior permanent magnet synchronous motor motor prototype. [ABSTRACT FROM AUTHOR]

This paper proposes a model predictive control based on three voltage vectors for an interior permanent-magnet synchronous motor in a rotating reference frame. The proposed method can obtain the reference voltage vector quickly by predicting only one voltage vector during one sampling period using the characteristics of the deadbeat control. In addition, to obtain better steady-state performance, the optimal vector duration ratios can be obtained from the cost function to minimize the error between the predicted reference voltage vector and the synthesis vector by using the switching sequence relationship of a symmetrical three vector, which is different from applying a single voltage vector in the conventional finite-control-set model predictive control (FCS-MPC). To verify the proposed method, the experimental results are compared with the conventional FCS-MPC and two-vector-based MPC. [ABSTRACT FROM AUTHOR]

In the back electromotive force (EMF)-based sensorless control of interior permanent magnet synchronous motor (IPMSM), the inverter nonlinearity and flux linkage spatial harmonics will possibly give rise to (6k ± 1)th harmonics in the estimated back EMF, especially the fifth and seventh harmonics. Those harmonics will consequently introduce (6k)th harmonic ripples to the estimated rotor position, especially the sixth harmonic component. In order to solve this problem, a bilinear recursive least squares (BRLS) adaptive filter is proposed and integrated into a sliding-mode position observer to suppress the dominant harmonic components in the estimated back EMF and as a result, the accuracy of the estimated rotor position can be greatly improved. A unique feature of the BRLS adaptive filter is its ability to track and suppress the specified harmonic components in different steady state and dynamic operational conditions. The proposed method can compensate for harmonic ripples caused by the inverter nonlinearity and machine spatial harmonics at the same time; this method is also robust to machine parameter variation, and the BRLS algorithm itself is machine parameter independent. The implementation of the proposed BRLS filter in the sensorless control of IPMSM is explained in details in this paper. The enhanced drive performances using the BRLS filter have been thoroughly validated in different steady state and dynamic operational conditions on a 1.5-kW IPMSM sensorless drive. [ABSTRACT FROM AUTHOR]

A nonlinear observer for a class of nonlinear interconnected systems is introduced. The proposed methodology facilitates the observer design for nonlinear systems. Sufficient conditions criteria are derived to ensure asymptotical convergence of the proposed observer. The convergence of the proposed observer is studied in both nominal and abnormal cases. The designed observer is applied for self-sensing control of interior permanent magnet synchronous machine (IPMSM) to estimate the rotor position, the rotor speed, the stator resistance, and the load torque. Performance of the proposed observer algorithm is evaluated through real-time experiments using an industrial benchmark. Two cases are employed to prove the performance capability of the proposed self-sensing control algorithm. The first case measures the performance under normal operating condition. The influence of parameter deviations on the proposed self-sensing control algorithm is discussed to prove the robustness of the proposed observer in the second case. The accuracy of the proposed self-sensing control algorithm is greater than 93 %. [ABSTRACT FROM AUTHOR]

Beat phenomenon is an important concern in the reduced dc-link capacitance motor drive system. In previous research works, the topic is mainly concentrated on the beat phenomenon caused by the interaction of the fluctuated dc-link voltage and the motor phase voltage. In this paper, another form of the beat phenomenon generated by the fluctuated dc-link voltage and the severely fluctuated load torque is investigated. The effect of the beat phenomenon on the grid current and the motor speed is analyzed, which fluctuate with the low-frequency oscillation. In order to improve the drive system performance, a power balancing controller is proposed to suppress the grid current fluctuation, and a resonant controller is utilized to regulate the periodic power signals. Meanwhile, the applied fluctuated torque suppression method could improve the performance of the motor speed, which is only sensitive to the frequency of the fluctuated load torque. Experimental results are provided to verify the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

The speed response of the interior permanent magnet synchronous motor (IPMSM) drive at low speeds was analyzed. To eliminate the effect of external disturbance or parameter uncertainty, a nonlinear speed control loop was designed based on the sliding-mode exponential reaching law, which reduces chatter, which is the major drawback of the constant reaching law sliding-mode control technique. The proposed nonlinear speed control eliminates speed ripples at low speed under load disturbance. The problem of speed convergence at low speed is caused by electromagnetic torque ripples, which cause shaft speed oscillations that affect drive performance. The main objective of the proposed method is to change the traditional IPMSM control design by compensating with an appropriate signal along the reference current and across the output of the speed control loop. To optimize the speed tracking performance during disturbances or parametric variations, a nonlinear speed control scheme is designed that can vigorously adapt to the change in the controlled system. The comparative analysis shows that the method provides excellent transient performance (e.g., fast convergence response, less overshoot, and fast settling time) and standstill performance (e.g., reduced steady-state error) compared with conventional control methods at low speed under varying load conditions. The method is easy to implement and does not require additional computational cost. To demonstrate the effectiveness and feasibility of the design approach, a numerical analysis was conducted, and the control scheme was verified using MATLAB/Simulink considering various operating conditions.

The active vector effects on torque and flux linkage are different in interior permanent magnet synchronous motor (IPMSM) systems at different times under direct torque control (DTC). These different effects may cause overcompensation or undercompensation to torque and flux linkage leading to large torque and flux linkage ripples in the IPMSM DTC systems. A novel duty ratio modulation strategy for the IPMSM DTC systems is presented, which considers these differences that are ignored in conventional duty ratio modulation strategies. The proposed duty ratio modulation strategy aims at minimizing torque ripple and flux linkage ripple, which makes sure that the control system can work in an optimum state. The active angle, the impact angle, the active factor, and the impact factor are first introduced. The active angel and the impact angle are used to get the active factor and the impact factor, respectively. Every sector is divided into five small sectors based on the impact angels, and then, a switching table is redesigned according to the small sectors division. Also, the vector selection rules for the redesigned switching table are described in details. Subsequently, an optimal duty ratio can be derived through the simplified duty ratio determination method. Finally, the effectiveness of the proposed novel modulation strategy is verified through the experimental results on a 100-W IPMSM drive system.

Considering the low reliability and poor adaptability of existing drum shear cutting parts, this paper presents a permanent magnet short-range cutting transmission system with a low-speed and high-torque interior permanent magnet synchronous motor (IPMSM) as the driving source and a sensorless control strategy based on a new sliding mode observer (SMO). To increase the robustness of the observer and reduce the error caused by chattering in the traditional SMO, the phase-locked loop technique is used instead of the traditional arc-tangent function estimation, and the sigmoid function is introduced to replace the traditional sign function; then, the sliding mode gain is adjusted through the fuzzy control algorithm in the new SMO. The scheme effectively improves the problems of the high failure rate caused by the long transmission chain of the shearer cutting section and the environmental impact for the mechanical sensor measurement results. Finally, the mathematical model of IPMSM based on the two-phase rotating coordinate system and end cutting load is established to verify the effectiveness and feasibility of the program. The results show that the new observer can accurately realize the speed and position estimation of the shearer cutting motor, and it has good dynamic response performance, observation accuracy, and robustness.

This paper presents a multi-objective optimal rotor design for an interior permanent magnet synchronous motor (IPMSM) based on finite element analysis. Due to the importance of torque characteristic in electromagnetic design of IPMSMs, the main efforts of this study are focused on finding a proper trade-off for its torque profile challenges. In this regard, in order to attain high average torque and low torque ripple, the influence of several key factors, such as the permanent magnet (PM) arrangements, PM positions and PM sizes, are examined. Subsequently, according to the outcomes of the performed sensitivity analysis, the appropriate variation interval of the parameters as well as their initial values is determined. Employing such a deterministic optimization algorithm, which does not need large sample points, minimizes the finite element computational cost and leads to accelerate the convergence process. The two-dimensional finite element model (FEM) of an IPMSM is used to perform a sensitivity analysis and establish a multi-objective FEM-based optimization.

In an interior permanent magnet synchronous motor, an adhesive such as bond is generally injected into the magnet tolerance to prevent vibration of the permanent magnet within the insertion space. In this case, a disadvantage is that the magnet tolerance does not contribute to the performance. In this paper, ferrofluid is inserted to improve the torque density, utilizing the magnet tolerance. When inserting ferrofluid into the magnet tolerance, it is important to fix the magnet because conventional adhesives are not used, and it is important that the ferrofluid does not act as a leakage path within the insertion space. In this study, a new rotor configuration using a plastic barrier that satisfies these considerations was introduced. The analysis was conducted through finite element analysis (FEA), and this technique was verified by comparing the simulation results and the experimental results through a dynamo test. It was confirmed that the no-load back electromotive force in the final model increased through ferrofluid injection.

This paper presents a maximum torque per ampere (MTPA) control scheme for interior permanent magnet synchronous motor drives. In this scheme, an enhanced signal injection technique is responsible for correcting the MTPA reference deviation due to motor parameter variations, and a derived MTPA control law is responsible for generating constant-parameter model-based MTPA current references to enhance the dynamic performance of the MTPA operation. Unlike previous signal injection techniques, the enhanced injection technique directly injects signals into the d- and q-axis currents and extracts the MTPA indicator from the reconstructed dc-link current. Hence, this enhanced injection technique avoids any transformations associated with polar coordinates, and it does not depend on a dc-link voltage sensor or a high-resolution speed sensor. The derived MTPA control law, unlike conventional MTPA control laws, can be realized in real time without mathematical approximations or lookup tables. With the combination of the enhanced signal injection technique and the derived MTPA control law, the proposed MTPA scheme can achieve an accurate and fast MTPA operation. Simulation and experimental results confirm the validity of the proposed MTPA scheme. [ABSTRACT FROM AUTHOR]

This paper mainly studies the influences of air-gap deformations on the electromagnetic performances and radial vibration characteristics of an interior permanent magnet synchronous motor (IPMSM) at peak rotating speed with rated power. Considering different air-gap states in the electromagnetic finite-element models of investigated IPMSMs, the effects of stator oval deformation, rotor centrifugal distortion, and both deformations on the air-gap magnetic flux field, radial and tangential magnetic force, and electromagnetic torque are analyzed and compared. Then, based on the accurate structural model of the stator system, the motor vibration characteristics are investigated with loading different electromagnetic force excitations on the stator inner face. Finally, the vibration experiments of the investigated IPMSM prototype are carried out to verify the results obtained by the simulations at a high-speed load condition. It is found that the air-gap deformations give a large increase in the particular vibration level. In order to improve the prediction accuracy of motor vibration characteristics, the air-gap deformations under all electromagnetic excitations, including magnetic force and torque pulsation, should be taken into consideration. [ABSTRACT FROM AUTHOR]

Reduced dc-link capacitance interior permanent magnet synchronous motor (IPMSM) drives have many advantages, such as longer lifetime, reduced cost, and higher power density. However, due to the dc-link voltage fluctuation, the dc-link voltage utilization rate and the torque ripples are two major issues in flux-weakening operation region. It is important to consider these two issues comprehensively when a flux-weakening control method is adopted. In this paper, the IPMSM torque ripples caused by the dc-link voltage fluctuation and the overmodulation are analyzed in depth. In order to reduce the torque ripples and increase the utilization rate of the dc-link voltage, a novel adjustable maximum voltage based voltage closed-loop flux-weakening method is proposed. By switching between the minimum dc-link voltage control mode and the extended dc-link voltage control mode, the torque ripples can be reduced effectively and a nearly maximum utilization of the dc-link voltage can be realized. The proposed flux-weakening control method only depends on the dc-link voltage and the stator current vector reference. Experimental results on a 2.2-kW IPMSM drive platform are provided to verify the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Fractional-slot concentrated-winding (FSCW) interior permanent magnet synchronous motors (IPMSMs) have been attracting considerable attention due to their high power density, high efficiency, short end winding, high slot fill factor, low cogging torque, excellent flux-weakening, and fault tolerance capability. However, compared to integral-slot distributed-winding (ISDW) IPMSMs, the key challenge of using FSCW configurations is the significant rotor losses, particularly at high speed. To figure out the IPMSM with which winding configuration is more suitable for electric vehicle (EV) application, the thermal behaviors of four IPMSMs with ISDW, single-, double-, and four-layer FSCWs are comprehensively and comparatively investigated in this paper. First, electromagnetic design and loss analysis of the four IPMSMs are investigated to meet the EV traction motor requirements. Second, finite-element method is employed to investigate the thermal performance of the IPMSMs under different rotational speeds and torque overload capacities. Thirdly, experiments implemented on an ISDW prototype are carried out to validate the presented analysis method. Finally, some conclusions are drawn for a suitable winding configuration selection and the PM traction motor design. [ABSTRACT FROM AUTHOR]

This paper presents a novel loss minimization based nonlinear controller for interior permanent magnet synchronous motor (IPMSM) drive to achieve both high efficiency and high dynamic performance. Traditionally, the dynamic performance of the drive is often ignored for any loss minimization controller or, loss minimization is ignored for robust controller. Therefore, in this paper, a loss model based controller is integrated to an adaptive backstepping based nonlinear controller in the design stage. In order to cope with parameter uncertainties, some motor parameters are also estimated online for the proposed loss model based nonlinear controller (LMNC). Moreover, stability of the proposed drive is demonstrated through Lyapunov's stability criterion and global asymptotic stability is assured through the application of Barbalat's lemma. The proposed LMNC-based IPMSM drive is implemented using a digital signal processor board DS1104 for a laboratory 5-hp motor. The performance of the proposed control scheme is investigated in both simulation and experiment at different load and speed conditions. The performance of the proposed LMNC is also compared with the conventional PI as well as nonlinear controller without any loss minimization. It is found that the proposed LMNC is superior to the conventional benchmark PI controller or nonlinear controller. [ABSTRACT FROM AUTHOR]

This paper proposes the variable regularized affine projection algorithms (VR-APAs) for the online multiparameter estimation of the interior permanent magnet synchronous motors (IPMSMs). Unlike the conventional APAs with a fixed regularization factor, the normalized gradient of the mean-square error is introduced in the proposed VR-APA to update the variable regularization which ensures a fast convergence rate, accurate estimation, and low steady-state error. Moreover, the proposed VR-APA does not require any accurate priori information of the motor parameters, making it highly feasible for the IPMSM. In order to accurately estimate the stator d–q axis inductances, stator resistance, flux linkage, and load torque, the two-time scale approach in the proposed VR-APAs is used due to the difference in the IPMSM dynamics. Of various applications of the proposed VR-APAs, such as condition monitoring, fault analysis, and controller design, these estimated multiparameters are updated online to the adaptive decoupling PI controllers to achieve the robustness against the parameter variations due to the temperature increase and load disturbances under various operating conditions (i.e., speed change, load change, and speed reversal). Finally, the comparative experimental verifications via a prototype IPMSM with TMS320F28335 DSP programmed by Code-Composer-Studio are conducted to confirm the effectiveness of the proposed VR-APAs. [ABSTRACT FROM AUTHOR]

This paper proposes a variable structure speed controller (VSSC) that guarantees the robust transient performance against the external disturbances and parameter uncertainties of an interior permanent magnet synchronous motor (IPMSM) drive. Unlike the conventional VSSC applied to the IPMSMs, the proposed nonlinear compensating control term not only assures the robustness against the system uncertainties, but also implements the maximum torque per ampere technique. Furthermore, the convergence and stability of the proposed VSSC are fully proven through the Lyapunov theory by introducing reasonable bounded uncertainties which determine a feasible range for the system dynamics. The effectiveness of the proposed scheme is investigated through the simulation using MATLAB/Simulink and experiment using a prototype IPMSM drive system with a TI TMS320F28335 DSP. Finally, the proposed VSSC can ensure faster and more robust transient response than the conventional proportional-integral speed controller under the dynamic load conditions including the uncertainties. [ABSTRACT FROM AUTHOR]

The current reconstruction strategies using single current sensor in the motor drives are widely researched. However, the sampled currents do not represent the average values within the modulation period, especially for the asymmetric modulation or asymmetric sampling solutions. This is due to the following two reasons: 1) The detected current values obtained at different sampling points are utilized to calculate the three-phase currents; and 2) the detected instantaneous currents are applied to estimate the average current values. In this letter, the current change rates under different action vectors are estimated to compensate these errors in a three-phase four-switch interior permanent magnet synchronous motor (IPMSM) drive with single current sensor. The effectiveness of the proposed strategy is verified by experimental results on a 5-kW IPMSM motor prototype, which shows that the current reconstruction errors are reduced after compensation. [ABSTRACT FROM AUTHOR]

This paper proposes a position sensor fault detection scheme using single dc-bus current sensor for interior permanent magnet synchronous motor (IPMSM) drives. The three-phase currents are derived from the single current sensor, and the accuracy uncertainty of the sensor is also considered. The six active vectors are divided into three groups for sensor calibration. Then, the proposed dc-bus current sensor offset error calibration method is implemented by setting two opposite basic vectors together and measuring the current values on both sides of the junction point in a same time interval. If the sum of the two sampled currents is not zero, it indicates that the offset error of the dc-bus current sensor exists. Therefore, a corresponding compensation method is proposed. Meanwhile, the dc-bus current slopes under different switching states are closely related to the rotor position, which are utilized for position sensor error detection. Finally, the effectiveness of the proposed scheme is verified by experimental results on a 5-kW IPMSM motor prototype. [ABSTRACT FROM AUTHOR]

This paper proposes a new sensorless control scheme of interior permanent magnet synchronous motors (IPMSMs) using high-frequency (HF) orthogonal square-wave voltage injection into a stationary reference frame (SRF). This method is an improvement on the conventional HF rotating sinusoidal voltage injection into the SRF. First, discrete sequences of the HF currents are applied to establish the whole signal process. Then, a position estimation method without low-pass filters is proposed, and the phase shifts caused by high-pass filters are also reduced. Therefore, the proposed sensorless control method would not be adversely affected by digital filters, which can solve the common drawbacks of the current SRF-based injection methods. Furthermore, the digital delay in drive systems is considered, and its negative influence can be eliminated as well. The sensorless control method is verified by experiments on a 2.2-kW IPMSM drive platform. [ABSTRACT FROM AUTHOR]

This paper examines how changing the magnetic orientation of permanent magnets in concentrated winding interior permanent magnet synchronous motors (IPMSMs) affects their demagnetization resistance. We evaluated a prototype for demagnetization at 180 °C that consists of a 130° V-shaped rotor core in which parallelogram magnets with oblique orientation are arranged and confirmed by finite element analysis where the demagnetization resistance increases as magnetic field orientation angle $\alpha $ becomes larger. For demagnetization evaluation of the prototype, it is easier to change the rotor core shape of a two-pole test rotor of a multipole IPMSM than a multipole rotor, and the demagnetization evaluation is performed using a small number of magnets. [ABSTRACT FROM AUTHOR]

This paper proposes a modified sensorless control technique for an interior permanent magnet synchronous motor over its full-speed range based on current derivative measurements and fundamental pulsewidth modulation excitation (FPE). The proposed method employs measurement of the current derivative at only one active-voltage vector at low speeds, and at one active-voltage vector and one zero-voltage vector at medium and high speeds during each pulsewidth modulation (PWM) cycle, in contrast to two active- and two zero-voltage vectors in the conventional FPE method. The theoretical analysis is developed based on the three-phase model of the machine. The rotor position and speed are estimated at PWM frequency. In addition, the selection voltage vectors for current derivative measurement as well as the pulse stretching scheme for extending and compensating the selected voltage vectors is proposed in order to improve the accuracy of the current derivative measurement and to minimize the current distortion. The experimental results show that the proposed method results in a considerable improvement of the estimation accuracy at low speeds, a significant reduction of current distortion compared to the conventional FPE method and a full-speed range operation from no load to full load. [ABSTRACT FROM AUTHOR]

High-frequency (HF) signal injection methods have been widely employed in the sensorless control of interior permanent magnet synchronous motor (IPMSM) drives from zero to low speed. However, the control performance will be deteriorated severely when the motor subjects to the disturbance. To cope with this issue, an enhanced linear active disturbance rejection control (LADRC)-based HF pulse voltage signal injection method is proposed in this paper. The cascaded extended state observer is established to guarantee relatively timely and accurate estimation of the total disturbance. The linear control law is generated to compensate for the total disturbance in a feedforward way, which reduces the plant to approximate a canonical first-order integral. The tracking performance and the stability of the enhanced LADRC are analyzed theoretically. Maximum torque per ampere control is adopted to reduce the estimation burden by making full use of the reluctance torque, which helps to further improve the tracking performance of the enhanced LADRC. Finally, the validity of the proposed sensorless control scheme is verified on a 2.2-kW IPMSM drive platform. [ABSTRACT FROM AUTHOR]

In this paper, direct torque and flux control of interior permanent magnet synchronous motor has been described in the stator flux field-oriented reference frame based on adaptive input-output feedback linearization (AIOFL) control method. The proposed control method does not need to know the motor two-axis inductances, the rotor permanent magnetic flux linkages, and the rotor position. However, the knowledge of the stator resistance is mandatory and that is estimated by AIOFL method. In practice, the rotor speed is approximately estimated by using the derivation of the stator flux vector angle in the stator stationary reference frame. The experimental and simulation results presented in this paper show the effectiveness and capability of the proposed control approach. [ABSTRACT FROM AUTHOR]

The effects of cross-coupled inductance are significant in high power density motors. It is observed here that the cross-coupled inductance causes current and voltage overshoots in the high-speed region. As the required voltage exceeds the voltage limit, the system becomes unstable. Here, the current dynamics are analyzed with a reduced model that incorporates a cross-coupled inductance, $L_{qd}$. Further, it is shown that $L_{qd}$ makes an uncanceled zero in the current transfer function, which invokes the overshoot. It can be compensated with an estimate $\hat{L}_{qd}$. However, it is not easy to obtain correct estimates of $L_{qd}$ in a wide current range. In this paper, an online overshoot suppression algorithm is proposed by using a high-pass filter. The simulation and experimental results provide some evidence for the effectiveness of the proposed algorithm. Finally, it is shown experimentally that the proposed algorithm cured the vehicle hunting problem after tapping off the gas pedal in a high-speed operation. [ABSTRACT FROM AUTHOR]

The torque ripple, current fluctuation and variable switching frequency of conventional hysteresis current controller (CHCC) under different loading condition and motion variation is inevitable, which demands effective implementation of the existing current controller by which it will be possible to get rid of these limitations. This paper presents enhancement in performance of a vector controlled based Interior Permanent Magnet Synchronous Motor (IPMSM) drive system by using an adaptive hysteresis current controller (AHCC). This controller minimizes torque ripple, current error and is capable of providing nearly constant switching frequency by modifying its bandwidth according to the changes in the system parameter or when the system is subjected to any kind of disturbances and load variation. Initially the study is carried out in MATLAB-Simulink environment and then the test result is experimentally validated through hardware implementation with the help of DSP TMS320F2812 which provides a complete digital control system with high effectiveness and fast computational skill. [ABSTRACT FROM AUTHOR]

This paper deals with the optimization design process of an interior-type permanent magnet synchronous motor (IPMSM) for electric compressors of air conditioners applied to electric cars and hybrid vehicles. Based on a prototype IPMSM, we identified the current level for efficiency and cogging torque using finite-element analysis (FEA). The IPMSM’s main design variables are optimized to primarily satisfy the target of efficiency and cogging torque. A second optimization design is carried out using the response surface method (RSM) for the main design variables obtained from the Taguchi method analysis. As a result, the optimization design is carried out through a two-step optimization design process using the Taguchi method and RSM. The IPMSMs are analyzed using FEA, and their validity is confirmed by comparing the test results against each step-by-step model. We validate an effective optimization design process using a two-stage design process. We conclude that the proposed approach provides an effective design method for engineers. [ABSTRACT FROM AUTHOR]

A conventional railway vehicle adopts the rigid-axle wheelset (RW) due to its inherently characteristics of automatic restoration capability without additional actuators or control. RW allows the railway vehicle to run to the center of the rail. However, there is no restoring force in independently rotating wheelsets (IRWs), if only traction torque control is applied as in RW. As a result, excessive wear and noise between the rail and the wheel are generated, and in severe cases a derailment may occur. In order for IRWs to generate restoring force, an active control strategy is needed that controls the left and right wheel torques independently. Because of this control characteristic, unlike the conventional traction motor of RW, fast torque response and precise torque control performance are required. In this paper, the design and modeling of an IRW traction motor were accomplished considering active restoring force control. A quasi-semi-closed slot structure is proposed to improve the power density and restoring torque control performance. In the next step, control simulation was performed using a static interior permanent magnet synchronous motor model considering slot harmonics. The validity of the proposed methods was verified through experiments using a dynamo. [ABSTRACT FROM AUTHOR]

An interior permanent magnet synchronous motor (IPMSM) drive system with machine learning-based maximum torque per ampere (MTPA) as well as flux-weakening (FW) control was developed and is presented in this study. Since the control performance of IPMSM varies significantly due to the temperature variation and magnetic saturation, a machine learning-based MTPA control using a Petri probabilistic fuzzy neural network with an asymmetric membership function (PPFNN-AMF) was developed. First, the d-axis current command, which can achieve the MTPA control of the IPMSM, is derived. Then, the difference value of the dq-axis inductance of the IPMSM is obtained by the PPFNN-AMF and substituted into the d-axis current command of the MTPA to alleviate the saturation effect in the constant torque region. Moreover, a voltage control loop, which can limit the inverter output voltage to the maximum output voltage of the inverter at high-speed, is designed for the FW control in the constant power region. In addition, an adaptive complementary sliding mode (ACSM) speed controller is developed to improve the transient response of the speed control. Finally, some experimental results are given to demonstrate the validity of the proposed high-performance control strategies.

In this paper, the Novel Immune Algorithm (NIA) is proposed for an optimal design of electrical machines. By coupling the conventional Immune Algorithm and Steepest Descent Method, the NIA can perform fast and exact convergence to both global solutions and local solutions. Specifically, the concept of an antibody radius is newly introduced to improve the ability to navigate full areas effectively and to find new peaks by excluding already searched areas. The validity of the NIA is confirmed by mathematical test functions with complex objective function regions. The NIA is applied to an optimal design of an interior permanent magnet synchronous motor for fuel cell electric vehicles and to derive an optimum design with diminished torque ripple.

In the applications of rail transit and electric vehicles, sensorless control of interior permanent magnet synchronous motor (IPMSM) usually uses high frequency (HF) signal injection in low speed or zero speed. Rotating HF signal injection based on the stationary reference frame can identify the rotor position, but its accuracy is easily affected by various nonlinearities of the control system and stator resistance. In this paper, the causes of rotor position estimation deviation are analyzed and deduced in detail. It is proposed that the rotor position estimation deviation can be divided into high frequency phase deviation (HFPD) and stator resistance phase deviation. On the basis of these analyses, a novel sensorless rotor position estimation strategy for IPMSM is proposed. This strategy can theoretically eliminate the HF phase deviation caused by the nonlinearity of the control system and reduce the phase deviation caused by the stator resistance. Although the factors that cause the estimation deviation of rotor position may change with the time and the operation status of the motor, the proposed strategy has the characteristics of online calculation and real-time compensation, which can improve the accuracy of the estimated rotor position. In addition, this paper provides a detailed theoretical derivation of resolving rotor position considering stator resistance and HF phase deviation. Finally, the result analysis on an IPMSM demonstrate the correctness of the theoretical analysis and the effectiveness of the strategy.

In this paper a multiobjective optimal design method of interior permanent magnet synchronous motor ( IPMSM) for traction applications so as to maximize average torque and to minimize torque ripple has been presented. Based on train motion equations and physical properties of train, desired specifications such as steady state speed, rated output power, acceleration time and rated speed of traction motor are related to each other. By considering the same output power, steady state speed, rated voltage, rated current and different acceleration time for a specified train, multiobjective optimal design has been performed by Broyden–Fletcher–Goldfarb–Shanno (BFGS) method and finite element method (FEM) has been chosen as an analysis tool. BFGS method is one of Quasi Newton methods and is counted in classic approaches. Classic optimization methods are appropriate when FEM is applied as an analysis tool and objective function isn’t expressed in closed form in terms of optimization variables.

In this paper, a new mathematical modeling for a six-phase interior permanent magnet synchronous motor (IPMSM) is presented. The proposed model utilizes two synchronous reference frames. First, the flux model in the $abcxyz$ frame is mapped into the stationary $dq$ frames and then to two synchronous rotating frames. Then, differentiating the flux models, voltage equations are derived in rotating frames. Through this analysis, the interaction between the $abc$ and $xyz$ subsystems is properly described by a coupling matrix. The torque equation is also derived using the two reference current variables. Flux model was verified through FEM analysis. Experiments were done using a 100 kW six-phase IPMSM in a dynamo system. The validity of the torque equation was checked with some experimental results under a shorted condition on an $xyz$ subsystem. [ABSTRACT FROM AUTHOR]

A maximum torque per ampere (MTPA) control based on virtual signal injection for an interior permanent magnet synchronous motor with fast dynamic response is proposed in this paper. A small square wave signal is mathematically injected into the current angle for accurately tracking MTPA points. The extracted derivative of electromagnetic torque is utilized to compensate the initially set current angle to the real MTPA operation current angle. Due to the absence of bandpass and low-pass filters, which are essential in the sinusoidal injected signal scheme, this method shows good dynamic response. By incorporating a modified equation for the torque after signal injection, the steady-state accuracy is also enhanced. The $d$ - and $q$ -axis current references are obtained through the current vector magnitude and optimal current angle instead of using the torque equation with nominal motor parameters, which guarantees the accuracy of the output torque. The proposed scheme is parameter independent, and no real signal is injected to the current or voltage command. Thus, the problems of the high-frequency signal injection method are avoided. A prototype is set up, and experiments are carried out to verify effectiveness and robustness of the proposed control scheme. [ABSTRACT FROM AUTHOR]

This paper investigates a high-performance finite-set model predictive control (FS-MPC) based on an optimal switching voltage vector technique for voltage-source inverter (VSI)-fed interior permanent magnet synchronous motor (IPMSM) drives. The proposed algorithm clamps one switch that supplies the largest phase current at each sampling interval while allowing the other two pole switches to remain active. Unlike the conventional FS-MPC scheme, the proposed scheme involves only two voltage vectors to obtain an optimal switching state with reduced switching losses and low computational cost without incorporating any additional parameters or constraints in the cost function. Thus, the proposed FS-MPC implemented on a DSP-based prototype exhibits high performance features (low switching losses and low harmonic distortion above rated speed) in constant torque and power regions. The experimental results on prototype VSI-fed IPMSM with TMS320F28335 are presented under various conditions to demonstrate the efficacy of the proposed scheme compared with the conventional FS-MPC. [ABSTRACT FROM AUTHOR]

This paper proposes a new phase current reconstruction scheme without using null switching states for interior permanent magnet synchronous motor (IPMSM) sensorless control. The phase currents are independently reconstructed and no additional test voltage pulses are required. First, the principle of the basic phase current reconstruction for IPMSM drive system is analyzed in detail. Then, an independent phase current reconstruction scheme without using null switching states is proposed. The current reconstruction dead zone is divided into six sectors, and each sector is split into three parts with corresponding vector synthesis methods. Meanwhile, the null switching states, V000 and V111, are removed from the proposed scheme. In this case, the zero vector is synthesized by the other available vectors. Finally, the reconstructed three-phase currents are utilized for high frequency sine-wave voltage injection-based position estimation. The effectiveness of the proposed scheme is verified by experimental results on a 5 kW IPMSM motor prototype, which shows that the reconstructed phase currents track the actual currents accurately under different working conditions. [ABSTRACT FROM PUBLISHER]

A novel maximum torque per ampere (MTPA) method based on power perturbation for a field-oriented control interior permanent magnet synchronous motor (IPMSM) drive system is proposed in this study. The proposed MTPA method, which is parameter independent and can improve the motor operation at both start-up and low speed, is designed based on the power perturbation by using the signal injection in the current angle. Moreover, the influence of current and voltage harmonics to the MTPA control can be eliminated effectively. Furthermore, to enhance the robustness of the control system, an online tuning scheme for an integral-proportional controller using a new wavelet fuzzy neural network with disturbance torque feedforward control is developed where the disturbance torque is obtained from an improved disturbance torque observer. Finally, some experimental results using an IPMSM drive system based on a low-price digital signal processor are presented. From the experimental results, the proposed control approach can guarantee the control performance of the speed loop, even under a cyclic fluctuating load. [ABSTRACT FROM PUBLISHER]