Electromechanical Coupling Dynamic Characteristics of Differential Speed Regulation System Considering Inverter Harmonics Under Variable Operating Conditions

Abstract

The differential speed regulation system driven by inverters, motors and differential gear trains is a complex electromechanical system that achieves speed regulation and energy savings efficiently and economically. In this paper, the complete drive trains dynamic model of the differential speed regulation system with the inverter power supply-motor-differential gearbox-load is established. The inverter power supply considers constant voltage to frequency ratio control, sinusoidal pulse width modulation and inverter, the motors are modeled based on the equivalent circuit method, and the differential gear trains consider a lateral-torsional model with time-varying meshing stiffness and damping. The dynamic properties of the system are analyzed and compared with the variable frequency drive model considering inverter power supply and the direct drive model using ideal power supply under variable operation conditions. The results show that the variable frequency drive model varies more smoothly in the time domain and contains additional harmonic components in the frequency domain resulting from the coupling of the inverter triangle carrier frequency to the fundamental frequency of the power supply than the direct drive model. It also shows that the variable frequency drive model is a more realistic and rational model than the direct drive model. The complex coupling relationship can be seen in the inverter power supply-motor-differential gearbox-load system, where both inverter harmonics and mechanical meshing force harmonics are found in the dynamic response of the motor's electromagnetic torque, rotor speed; the inverter harmonics are also reflected in the mechanical meshing force harmonics.

Stiffness Modeling of Tooth Interior Fatigue and Tooth Flank Fracture and Their Fault Characteristics in Electromechanical Coupling Systems

“…Te mechanical vibration during the evolution of the fault is simulated by the electromechanical coupling dynamics model, and the fault characteristics were analyzed in the time domain, frequency domain, and phase diagram, respectively. Te motor and power supply parameters are listed in Table 5, which is calculated and chosen according to references [20,21,28] based on our model. In this paper, tooth root fracture (TRF), tooth fank fracture (TFF), and tooth interior fatigue fracture (TIFF) of gear fault characteristics will be studied.…”

“…Liu et al [19] developed a dynamic gear model by incorporating both the driving speed and the drag torque as external excitation sources and then proposed a solution method based on adaptive selection of the time-step method and the time-step reduced method to optimize the calculation process. Wang et al [20] considered the impact of the inverter on the electromechanical coupling system, constructed a variable-frequency drive electromechanical coupling model, and studied the dynamic characteristics of motor speed regulation. Han et al [21] established an electromechanical coupling dynamic model that includes a pair of fxed-axis gears and studied the impact of system parameters on vibration characteristics.…”

Research on dynamic characteristics of a multi-motor electric driving system caused by parasitic power

“…L q e q =L d ω r i d +ω r ψ f i q u q d-axis q-axis , MU + CU + KU = F (10) where: M, K, C, U and F are the whole mass, stiffness, dampling, vibration displacement and external exciting force/moment matrices of the MMDES, respectively. The parameters of PSGS and PMSM are shown Tables 1 and 2…”

“…Fan et al set up a dynamic model of dual-motor coupling driving system (DCDS) and proposed an analysis method of the transmission process for the DCDS, and the influence of meshing stiffness and excitation source on the dynamic characteristics were discussed, the results shown that the effect of the dynamic meshing force was affected by the rotational speed of the dual motors and increasing the meshing stiffness can significantly reduce the vibration amplitude of the low-order vibration [9]. Wang et al established a ECDM of the full drive trains of a differential speed regulation system including gearbox, load, motor and its inverter power supply, and the dynamic properties of the system were discussed under variable operation conditions, the results indicated that both inverter harmonics and mechanical meshing force harmonics can be observed in the electromagnetic torque and rotor speed of the motors [10]. Shu et al developed an ECDM of a MMEDS considering gear transmission system, load, motor and its control, and then its dynamic and synchronization properties were discussed, the results demonstrated that the current can be regarded as a signal to monitor the torque and its synchronous performance, and the vibration properties of MMEDS [11].…”