This article proposes an improved deadbeat predictive controller for permanent-magnet synchronous motor drive systems. It can eliminate the influence of the parameter mismatch of inductance, ...resistance, and flux linkage. First, the performance of the conventional predictive current method is investigated to analyze sensitivities of the electric parameters. Then, a composite sliding-mode disturbance observer (SMDO) based on the stator current and lumped disturbance is proposed, which can simultaneously estimate the future current value and lumped disturbance caused by the parameter mismatch of inductance, resistance, and flux linkage. Based on the discrete-time SMDO, currents are estimated and used to replace the sampled values to compensate one-step delay caused by the calculation and sampling delay. Both simulation and experimental performances of the proposed method have been validated and compared with the conventional control methods under different conditions. The comparison results show the superiority of the proposed predictive current control method based on the composite SMDO.
Automotive applications demand high efficiency, good reliability, and a wide operating speed range within limited dc bus voltage constraints. In this article, a zero degree displacement dual ...three-phase permanent magnet synchronous machines (PMSM) is derived from an original three-phase PMSM to enhance the power rating as well as the operating speed range. The proposed topology can be used as an alternative to the conventional configuration of three-phase PMSM with a bidirectional dc-dc converter for electric vehicles. Even though the commonly used dual three-phase PMSM with split-phase winding eliminates the sixth harmonic torque pulsation, a large circulating current is generated during six-step operation, which results in additional stator copper loss. In this article, six-step operation of the symmetric dual three-phase PMSM with zero degree winding displacement is proposed to achieve maximum inverter utilization. Both harmonic circulating current and torque pulsation were observed to be within satisfactory levels using this configuration. A changeover algorithm is also proposed to enable a smooth transition between closed-loop current vector control during low and medium speed operation to open-loop six-step voltage angle control for high speed operation. The performance of the proposed method is experimentally validated on a 3-kW dual three-phase PMSM drive.
The conventional finite control set-model predictive control (FCS-MPC) suffers from poor robustness against model mismatches. This paper presents an improved FCS-MPC with a reconstructed mathematical ...model to predict current variations without using a lookup table (LUT) or motor parameters. The model coefficients and current variations related to different voltage vectors can be updated during each control period. As a result, the prediction error is significantly reduced at low switching frequency when compared with the prior LUT-based model-free predictive current control (MFPCC). Additionally, the tracking accuracy of the proposed method at high speeds is improved due to the elimination of approximation error. Furthermore, a simple scheme is developed to suppress neutral-point-potential drift without knowledge of the dc-bus capacitor. Simulation and experimental tests, along with comparisons with prior arts carried out on a three-level inverter-fed surface-mounted permanent magnet synchronous motor drive, confirm the superiority of the proposed method.
Effective condition monitoring of motors is crucial in diverse electric powertrain systems, including applications in electric transportation and nuclear power plants. Vibration analysis, a key ...component of motor condition testing, aids in identifying equipment failures, assessing operational status, and guiding preventive maintenance. However, achieving high evaluation accuracy while minimizing the number of vibration sensors to reduce operational and maintenance costs poses a significant challenge. This article introduces a novel approach for vibration testing using a spatial-spectral-based inductive graph neural network. The proposed algorithm focuses on mining vibration sensor-based clusters to reveal spatial connectivity and spectral correlation patterns. It efficiently aggregates and extracts features from sensor graph signals near the target location, subsequently reconstructing vibration signals using convolutional networks to create a virtual sensor. To validate the effectiveness of the proposed method, experimental verification was conducted on a 21 kW interior permanent magnet synchronous motor testing rig equipped with Brüel and Kjær's vibration sensing equipment. The results demonstrate the algorithm's ability to enhance evaluation accuracy and reliability. This innovative approach not only contributes to the field of motor condition monitoring but also addresses the challenge of minimizing the number of vibration sensors, thereby reducing manual operation and maintenance costs associated with sensor networks.
A fixed switching period sliding mode control (SMC) for permanent-magnet synchronous machines (PMSMs) is presented. The aim of this paper is to design an SMC that improves the traditional PI-based ...field-oriented control transient response, as well as to reduce the switching frequency variations of the direct torque control. Such SMC requires a decoupling method of the control actions, which also brings constant switching functions slopes. These constant slopes allow to calculate the required hysteresis band value to control the switching frequency. The digital implementation degrades the performance of the hysteresis comparator, and as a consequence, the previously calculated band becomes inaccurate to regulate the switching frequency. In order to recover the analogue hysteresis band comparator performance, a predictive algorithm is proposed. Finally, a set of experimental results with constant switching frequency during a torque reversal and speed control tests are provided.
This article presents a delay-suppressed sliding-mode observer (SMO) to observe the real-time rotor position of a permanent magnet synchronous machine (PMSM) controlled by vector control algorithms. ...First, in order to solve the low-pass filter (LPF) delay problem existing in the traditional signum function-based SMO, a brand new hyperbolic function is initially selected as the switching function. Because a hyperbolic function with a proper boundary layer is capable of reducing the chattering phenomenon of an SMO, it is not necessary to reemploy LPFs to eliminate the adverse impacts of chattering on the position estimation accuracy. In order to ensure the reachability and stability of the hyperbolic-function-based SMO, the observer gain is calculated by the means of a Lyapunov function in this article. Second, to solve the problem of calculation delay caused by digital computation, a current precompensation scheme based on dual-sampling strategy in one switching period is proposed. After compensating the calculation delay, the accuracy of position estimation as well as the motor control performance can be improved. Finally, the proposed SMOs with and without delay compensation are verified by both simulation and experiments that are conducted on a three-phase 1.5-kW PMSM drive prototype.
Dual permanent magnet synchronous motors (PMSMs) based electric powertrain has been widely used in electric vehicles. Torque ripple caused by current measurement errors has a huge impact on the ...performance of dual-PMSM based electric powertrain. Currently, the measurement errors of current sensors in a dual-PMSM system are individually calibrated results in inconsistent calibration standards. The inconsistent calibration for errors of current sensor affects the current distribution of dual-PMSM based electric powertrain, thus making the motors unable to output power based on the specified ratio. To unify the calibration standards of dual-PMSM subsystems, a fast calibration method with high reliability is proposed in this article. The proposed calibration method is able to: check the rationality of the compensation values to eliminate the wrong value in the sampling process, and calibrate within one second even under the conditions of load distribution, speed mutation, no-load, interference or noise. A 2 kW dual-PMSM based electric powertrain testing rig is employed to verify the effectiveness of proposed calibration method.
This paper investigates the improved switching-table-based direct torque control strategies (ST-DTC) for dual three-phase permanent magnet synchronous machine drives. The classical ST-DTC scheme for ...dual three-phase drives is usually seriously penalized by significant current harmonics, which cause large losses and reduce the efficiency of the drive system. Hence, a modified switching table consisting of 12 new synthetic voltage vectors is proposed. With this new switching table, not only the variables relating to the torque production are well controlled, but also the variables contributing to the current harmonics are eliminated successfully within one sampling period. Furthermore, a simple modified torque regulator is proposed to reduce the torque ripple and the steady-state error of torque which is usually observed in the real-time system. The switching sequence which is most suitable for the implementation of the real-time system has been proposed to minimize the computation burden. The proposed strategy only changes the switching table and torque regulator without any major modifications, and hence, the merits of the classical direct torque control, i.e., simple structure and good robustness, are still preserved. The experimental results validate the effectiveness of the proposed strategy.
In the double-vector-based model predictive torque control (MPTC), two voltage vectors are applied in one control period. Due to a large number of possible combinations among voltage vectors, the ...determination of optimal voltage vector pair is often complicated. This article proposes a new approach to reduce the number of candidate active voltage vectors. The concept is to preselect the active voltage vectors according to the stator flux vector error. The proposed MPTC is implemented in a stationary frame and avoids the complicated coordinate transformation as well as the tangent inverse calculations. Furthermore, a promising approach is conceived for calculating the duty cycle of active voltage vector, which can contribute to the less dependence on the system model, thus alleviating the sensitivity to motor parameter variations. To further improve the steady-state performance, a modified three-vector-based MPTC is newly put forward. Meanwhile, the proposed duty cycle calculation method is used to achieve the deadbeat control of torque and stator flux. Theoretical analyses and experimental results are given to verify the effectiveness of the proposed MPTC methods.
The article proposes an enhanced deadbeat predictive current control for permanent magnet synchronous motor (PMSM) using iterative sliding mode observer to improve the current control accuracy. The ...inevitable deadtime and distortion of flux linkage, will lead to large periodic current ripples related to the speed, which may degrade the performance of the motor control. To overcome these problems and improve the robustness of the controller, the iterative learning control (ILC) and sliding mode observer are combined, and feedforward to the deadbeat controller for prediction accuracy improvement. Moreover, in order to satisfy the requirements of the variable speed operation of the motor, the ILC is enhanced to achieve spatial learning ability. Experimental results are finally implemented on STM32 based platform to validate the effectiveness of the proposed method for current ripples suppression and adaptability to variable speed.
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