Search Results (5)

This paper presents an electromechanical coupling model integrating an equivalent magnetic network (EMN) model of a dual three-phase permanent magnet synchronous motor (DTP-PMSM) with the dynamic model of a helical planetary gear transmission system. Using this model, this study analyzes the dynamic characteristics of an electric drive system, specifically motor phase current, electromagnetic torque, and gear meshing force, under self-fault-tolerant control strategies. Simulation and experimental results demonstrate that the self-fault-tolerant control strategy enables rapid fault tolerance during open-phase faults, significantly reducing system fault recovery time. Meanwhile, compared to the open-phase faults conditions, the self-fault-tolerant control effectively suppresses most harmonic components within the system; only the second harmonic amplitude of the electromagnetic torque exhibited an increase. This harmonic disturbance propagates to the gear system through electromechanical coupling, synchronously amplifying the second harmonic amplitude in the gear system’s vibration response. This study demonstrates that self-fault-tolerant control strategies significantly enhance the dynamic response performance of the electric drive system under open-phase faults conditions. Furthermore, this study also investigates the electromechanical coupling mechanism through which harmonics generated by this strategy affect the gear system’s dynamic response, providing theoretical support for co-optimization electromechanical coupling design and fault-tolerant control in high-reliability electric drive transmission systems. Full article

The impedance of the harmonic plane in a dual three-phase permanent magnet synchronous motor (DTP-PMSM) is very low, meaning that even small harmonic voltages can induce significant harmonic currents, particularly at the fifth and seventh harmonic frequencies. These harmonic currents can severely degrade system performance and increase losses. To address this issue, the mechanism of harmonic current generation due to non-sinusoidal back electromotive force (EMF) and inverter nonlinearity is first analyzed. Then, to overcome the challenge of excessive controllers in traditional harmonic suppression strategies, a rotational coordinate transformation of the harmonic plane current is employed, which unifies the controllers and reduces their number. Since traditional proportional-integral resonant (PIR) controllers are ineffective at a high-speed region, an improved PIR controller for the harmonic plane is proposed. This controller incorporates digital delay compensation, phase compensation, and discretization correction to minimize the deviation between the discretized resonant frequency and the actual frequency. These enhancements enable harmonic suppression across the entire speed range and under varying load conditions, significantly reducing harmonic currents. Finally, the proposed harmonic current suppression strategy is experimentally validated. Full article

The dual three-phase permanent magnet synchronous motor (DTP-PMSM) under a V/f control framework is widely applied in belts, fans, pumps, etc. However, the oscillation in power and rotor speed is difficult to quantify and suppress, due to the higher-order model of the DTP-PMSM. Thus, a power-revolutions per minute (RPM) reduced-order model and power control strategy of the DTP–PMSM are proposed for oscillation description and suppression. Firstly, according to the structure and V/f control framework, the reduced-order model is proposed under a power-RPM scale with coupled performances between sub-PMSMs, and then the decoupled method is employed. Moreover, the oscillated performances of power and rotor speed are detailed in small signals. Secondly, a power control strategy is proposed, including active power feedforward for active damping and reactive power droop control for high power quality and approaching optimal torque per ampere. Compared with the traditional strategies, the proposed method can achieve a stable and efficient operation, with a higher power factor of the DTP–PMSM, less stator current, and lower electromechanical power loss. Finally, an experimental platform of the DTP–PMSM is set up for the correctness and superiority of the proposed method. Full article

This research proposes a strategy to diagnose open-phase faults (OPF) and open-switching faults (OSF) in dual three-phase permanent magnet synchronous motor (DTP-PMSM) inverters. The method is based on the dual d–q predictive current model and involves establishing a mathematical model and utilizing the finite control set model predictive current extraction technique to predict the motor current. It then analyzes the characteristics of the switching-tube current under both normal and fault conditions. Finally, a fault predictive current model is introduced and the residual is calculated based on the predicted fault current value and the actual measured current value to diagnose the inverter fault. The proposed method effectively overcomes misjudgment issues encountered in traditional open-circuit fault diagnosis of inverters. It enhances the system’s response speed during dynamic processes and strengthens the robustness of diagnosis algorithm parameters. The experimental results demonstrate that the proposed method can rapidly, effectively, and accurately diagnose open-circuit faults presented in this paper fastest within one-fifth of a current cycle. It achieves a diagnostic accuracy rate of 97% in the dual three-phase permanent magnet synchronous motor drive system. Full article

Dual three-phase (DTP) permanent magnet synchronous motors (PMSMs) are specialized machines which are commonly used for high power density applications. These machines offer the merits of high efficiency, high torque density, and superior supervisor fault tolerant capability compared to conventional three-phase AC-machines. However, the electrical structure of such machines is very complicated, and as such, control becomes challenging. In conventional vector controlled DTP-PMSMs drives, the components of the dq-subspace are associated with electromechanical energy conversion, and two currents, i.e., I_d and I_q belonging to this subspace, are used in feedback-loops for control. Such orthodox control methods can cause some anomalies e.g., the voltage source inverter’s (VSI) dead time effect and other nonlinear factors, and can induce large harmonics. These glitches can be greatly alleviated by the introduction of the two-extra current loops to directly control the currents in Z₁Z₂-subspace in order to suppress the insertion of harmonics. In this paper, two approaches—one with two-current loops and other with four-current loops—for vector controlled DTP-PMSMs are investigated with the aid of different MATLAB-based simulations. Furthermore, in the paper, the influence of additional current loops is quantified using simulation-based results. Full article