Main Circuit Model Research Articles

Analysis of electromagnetic vibration and noise of permanent magnet synchronous motor based on field-circuit coupling

In order to study the influence of harmonics on the vibration and noise of permanent magnet synchronous motor, this paper introduces an analysis method based on field-circuit coupling, and establishes a complete analysis process from the control strategy to the vibration and noise response of the motor. Firstly, the coupling model including control strategy, main circuit model and electromagnetic field model is established. Secondly, the finite element model of the permanent magnet synchronous motor under the influence of coupling is established to analyze and compare the electromagnetic force wave characteristics of the coupling excitation and the sinusoidal excitation. Then, the coupled electromagnetic force is loaded into the structural field to simulate and calculate the vibration and noise. Finally, the effectiveness of the model is verified through experimental sound pressure level comparison under steady-state and speed-up conditions, and it provides a reference for vibration and noise prediction of the motor system.

Transient Study on Passing Neutral Section of Electronic Switch Considering Devices Delay Time

The passing neutral section scheme by using electronic switches instead of vacuum circuit breakers can shorten dead time of locomotives, and can eliminate the problem of locomotive deceleration. This paper constructed the traction power supply system model and the detailed main circuit model of Chinese standard EMU, including high voltage system and traction converter based on Matlab/Simulink. Then the scheme of using electronic switch is designed, and the influence of delay time required for the detection and action of the devices is considered. By comparing the simulation and measurement data, the accuracy of the model is verified, and analysed the transient response of passing neutral section when considering the delay time.

Capacitor Aging Detection in a DC–DC Converter Output Stage

One of the most significant reliability issues in switching-mode power supplies is electrolytic capacitor degradation caused by aging. This paper proposes an output voltage transient analysis method to detect capacitor wear-out at the output stage of a step-down dc–dc converter. Changes in the converter output voltage dynamics are evaluated by analyzing the output voltage step response with respect to a decrease in the capacitance. The sensitivity of the method is assessed with respect to parameter variations using an equivalent main circuit model. The feasibility of the presented method is verified by experimental tests using a converter prototype. The results show that the presented method is practical and adequate for detecting capacitor degradation in various operating conditions.

Research on Inductive Power Charging Device of Unmanned Ground Vehicle

It is important to charge accumulator automatically on unmanned ground vehicles. A kind of inductive power charging system, with rotary type coupler and series-resonant power converter of full bridge, is designed. The working progress of resonant circuit and main circuit is simulated. The result of experiments shows that the simulation model of main circuit agrees well with practice and can instruct design of power converter in the future. The efficiency of power transferring decreases with coupler air gap increasing. The designed inductive charging device can charge accumulator with constant current while the air gap is 1.2 mm.

Measurements and Simulations of DTC Voltage Source Converter and Induction Motor Losses

Energy efficient pulse-width modulation inverters are widely used to control electrical machines accurately for process needs. The pulse-width modulation, however, has also adverse effects and produces additional losses in the motor. These losses increase the motor temperature and result in derating of the machine power in converter use. A reliable and reasonably accurate loss model of an induction motor drive system is important for the performance prediction of a variable-speed drive. A two-level frequency converter main circuit model is coupled to a finite-element method motor model. The drive model is controlled by closed-loop direct torque control. The frequency converter losses are calculated analytically, and the finite-element method motor model provides an analysis of the motor losses. The simulation results are compared with measurement results.

Modeling and Analysis of Arc Weld Inverter Based on Double Closed-Loop Control

According to the soft-switching pulsed SAW (Submerged arc weld) weld power supply based on the double closed-loop constant current control mode, a small signal mathematic model of main circuit of soft-switching SAW inverter was established by applying the method of three-terminal switching device modeling method, and the mathematic model of double closed-loop phase-shift control system circuit was established by applying the method of state-space averaging method. Dynamic performance of the inverter was analyzed on base of the established mathematic model, and the tested wave of dynamic performance was shown by experimentation. Research and experimentation show that relation between structure of the power source circuit and dynamic performance of the controlling system can be announced by the established mathematic model, which provides development of power supply and optimized design of controlling parameter with theoretical guidance.

Modeling and Analysis of Submerged Arc Weld Power Supply Based on Double Closed-Loop Control

According to the soft-switching pulsed SAW (Submerged arc weld) weld power supply based on the double closed-loop constant current control mode, a small signal mathematic model of main circuit of soft-switching SAW inverter was established by applying the method of three-terminal switching device modeling method, and the math-ematic model of double closed-loop phase-shift control system circuit was established by applying the method of state-space averaging method. Dynamic performance of the inverter was analyzed on base of the established math-ematic model, and the tested wave of dynamic performance was shown by experimentation. Research and experimentation show that relation between structure of the power source circuit and dynamic performance of the controlling system can be announced by the established mathematic model, which provides development of power supply and optimized design of controlling parameter with theoretical guidance.