充电机是轨道车辆重要的车载电气设备,为实现轨道车辆车载充电机的高性能控制,本文针对一种AC/DC型双向充电机的矢量控制方法进行仿真研究.首先明确充电机矢量控制方法应实现的控制目标,其次从坐标变换、电压外环与电流内环PI调节器设计、空间矢量脉宽调制3方面阐述算法的基本原理,最后对算法控制动力电池充电的过程进行仿真验证.充电电压仿真结果与设定值相同,逆变侧的功率因数及谐波总含量满足车载充电机设计要求,证明在算法控制下充电机可以实现控制目标.

Energy-saving, punctuality and smoothness are difficult to achieve in the operation of heavy haul train.This paper proposes a multi-objective method for speed curve optimization.Firstly, a quadratic programming optimization model is established, using train kinetic energy and train force as independent variables and several goals of energy conservation, smoothness, and target speed tracking.Under the supplied weight vector, the model can realize the ideal speed curve under unbounded time.Secondly, in order to address the demand for punctuality, this paper develops a weight selection algorithm to optimal weight vector for any given trip time.Finally, a time-bounded multi-objective speed curve optimization model is proposed, which achieves energy conservation, punctuality and smoothness train operation.The simulation indicates that the proposed algorithm outperforms human driving in multi-objectives.And the designed time bounded weight selection algorithm is more efficient than the conventional linear approaching weight search method.

High-order harmonics in the traction power supply show negative effects on the safe and stable operation of the railway transportation system. There is a fixed resonant frequency in the traction network. When the harmonic current frequency produced by the locomotive matches the resonant frequency of the traction network, it will cause high-frequency resonant overvoltage. The propagation path of the high-order harmonics of the traction load is analyzed based on a V/v wiring traction transformer. The propagation characteristics of high-order harmonics on self-used equipment at 380 V low-voltage side and 27.5 kV high-voltage side are expounded. A simulation model for the low-voltage self-consumption power system is established and the singular value decomposition algorithm is proposed to identify the harmonic impedance. The simulation results show that the proposed method can reduce the error to within 0.1%. Under realistic conditions, the overvoltage caused by high-order harmonics is difficult to identify. To solve this problem, an overvoltage identification algorithm for Electric Multiple Units based on a convolutional neural network is proposed. The ShuffleNet neural network model is then used to identify high-order harmonics overvoltage and other types of overvoltage. The overall accuracy of the proposed classification model can be improved from 97.12% to 98.44%. Better recognition and classification performances can also be achieved.

From the perspective of the whole vehicle, this paper introduces the main technical parameters, operation characteristics, analyzes energy requirements of the system through traction calculation, carries out the capacity allocation of hybrid power and selection of key components and configures the capacity of two core components of the system, diesel generator set and power battery pack. Then, according to the structure, output characteristics and fuel consumption of diesel generator set, the uniform function of drooping output voltage and fuel consumption curve at different speed and power of diesel generator set are established. The parameters, characteristics and SOC zonal operation diagram of power battery pack are briefly introduced.

The application of hybrid power system in EMU not only has the characteristics of low consumption and emission reduction but also can improve the reliability of power supply. The stability of the bidirectional DC/DC converter, which is connected with the energy storage device and the intermediate DC link, greatly affects the charging and discharging process of the energy storage device. In this paper, the mathematical model of the bidirectional DC/DC converter in the hybrid EMU system is studied. The modeling and transfer function analysis of Buck mode and Boost mode converters in detail are carried out by means of switching element average method. Moreover, the voltage and current double closed-loop control strategy of bidirectional DC/DC converter and the influence of DC capacitor C are introduced, which lays a foundation for further study on the stability of the whole hybrid EMU system.

When the silicon carbide (SiC) power module is applied to the energy storage converter of a hybrid locomotive, under the action of di/dt and loop stray inductance, it is easy to produce excessively high voltage overshoot, which affects the battery life and stimulates high-frequency oscillations, causing power devices to withstand greater electrical stress. In order to optimize the system layout and improve system performance, it is extremely necessary to accurately extract and evaluate the loop inductance. This paper takes the typical high-frequency converter structure as the object, establishes an equivalent model of the circuit, and quantitatively analyzes the loop inductance from a mathematical point of view. For the circuit after the parallel of absorption capacitor, the small signal model is used to analyze and reveal the role and influence of the absorption capacitor. Finally, the calculation results of the model are compared through a double-pulse experiment. The results show that the error between the model and the experimental results is about 1%, and the effect of evaluating the stray parameters of the converter circuit is good, and it can provide a theoretical support for the selection and design of the absorption capacitor.

This paper proposed an isolated gate driving circuit for Silicon Carbide MOSFET, which could survive high environment temperature up to 200℃. In this circuit, bipolar junction transistors (BJTs) were used as switch devices instead of Si MOSFETs because high temperature would weaken their turn-off capability. This circuit included two branches, gate charging branch and gate discharging branch, by which the source driving signal of 0V/5V could be adjusted to driving level of-5V/18V. Each branch used a bootstrap capacitor to accelerate the BJT turn-on process, thereby speeding up the gate driving current. The equivalent model of the driving circuit was built. The equation for calculating four main passive components was obtained, and the relationship between the main passive components and BJT current amplification coefficients was available. Accordingly, the temperature compensation principle was introduced. With the load condition of 85V/14.5A, the results from double-pulse test under a series of step-up temperature points were obtained. The turn-on time of SiC MOSFET decreased from 133.6ns at room temperature to 112.4ns at 200℃, while the turn-off time increased from 99.2ns at room temperature to 109.8 ns at 200℃. The influence of temperature is that, with the increase of temperature, the transconductance of SiC MOSFET increases, and the Miller platform voltage declines, which in turn affects the turn-on and turn-off time.

In this paper, a modeling method based on MATLAB/Simulink for a temperature-dependent SiC MOSFET in the entire working region was proposed. Using a supplementary test circuit, the output characteristics of a device in the saturated region were extracted. Based on these characteristics, the model covered the output characteristics of the device in the whole working region. From the output curves, three main parameters essential for modeling were derived. Based on the Si lateral double-diffused MOSFET model, a temperature-dependent static model of SCT20N120 was established by adding a temperaturedependent compensation voltage source to simulate the temperature characteristics of the threshold voltage and a temperature-dependent compensation current source to compensate for the drain current error in the linear region due to the differences in structure and material between Si and SiC. In addition, based on the gate equivalent circuit, the dynamic model of the target device was established. The temperature-dependent static simulation results could simulate the actual measured values well. Furthermore, based on the comparison between the dynamic simulation results involving the device's turn-on and turn-off process losses and the actual transient state losses derived from a double-pulse test under the conditions of V ds = 300 V, I d = 15 A, R g_exton = 18 Ω, and R g_extoff = 12 Ω at 200 °C, the maximum error was 6.7%.

Simulation is always the first step in the design of power converters. To maximally make the simulation results close to the experimental results, accurate models of all passive and active elements are necessary, which are the precondition for validating the expected behavior of the complete system including its converter topology and control algorithm without any prototype. For this reason, due to the wide use of Simulink in simulation of complex systems and to avoid the physical model that is too complicated to understand for many electrical engineers, an improved model for SiC power MOSFETs based on Simulink is proposed in this paper, which is suitable for wide temperature range application from 25 °C to 200 °C, even extended to lower or higher temperature easily. The static characteristics of SiC power MOSFETs are described by controllable current source whose behaviors depend on ambient temperature values. To get perfect output characteristic, a novel compensation method is presented. What's more, based on the equivalent circuit of SiC power MOSFETs, its dynamic characteristics with switching performance are analyzed in detail. The proposed model is validated with ST company's SiC power MOSFET SCT20N120 (1200V, 20A) in experimental tests.

In order to achieve online monitoring the downhole information related to ESP working state, an ESP downhole parameters monitoring system based on current loop data transmission method was developed. Compared with other methods, the current loop data transmission method was relatively insensitive to interference in harsh environment. By means of ESP motor's winding and symmetrical reactance located on the ground, the loop for current transmission could be built. The principle of current loop transmission and involved circuit were introduced. An experiment simulating the hostile downhole environment was conducted to test the transmission effect, by which the reliability and accuracy of current loop data transmission was demonstrated.

In order to achieve online monitoring the downhole information related to ESP working state, an ESP downhole parameters monitoring system based on current loop data transmission method was developed. Compared with other methods, the current loop data transmission method is relatively insensitive to interference in harsh environment. By means of ESP motor's winding and symmetrical reactance located on the ground, the loop for current transmission could be built. The principle of current loop transmission and involved circuit were introduced. An experiment simulating the hostile downhole environment was conducted to test the transmission effect, by which the reliability and accuracy of current loop data transmission was demonstrated.

In order to obtain the down hole information involving ESP equipment to guide oil production, a down hole multi-parameter monitoring system based on current loop data transmission method was developed. Compared with other transmission methods in harsh environment, the current loop data transmission method possesses obvious advantage in reliability and accuracy. By ESP motor's three-phase winding and three-phase symmetrical reactance on the ground, the loop could be realized. Meanwhile, the down hole circuit could be powered by means of the loop. After conditioned by electronics in down hole circuit, the current in the loop reflected the amplitude of sampled signal and thus the signal could be extracted when the current flowed through the up hole sampling resistance. In the up hole, the circuit based on ARM7 processor supplied power for down hole circuit and filtered the received signal, while the circuit based on ARM9 processor rectified and displayed data, and its abundant human-computer interaction function make operations more convenient.

近年来随着宽禁带器件的逐步商业化，其市场占有率迅速攀升。为了充分体现SiC器件的优势，本文以高温石油井下参数测量系统为背景，首先分析了SiC MOSFET开关过程，并总结了驱动要求。在此基础上设计了基于分立器件的SiC MOSFET高速隔离驱动电路，并搭建了双脉冲测试平台，对所设计的驱动电路性能进行了测试和验证，对200℃环境下的高温驱动电路设计具有重要借鉴意义。

本文设计了一种基于电流环的潜油电泵井下参数测量装置数据传输电路，该电路将1-2V经过调理的电压形式的测量信号调理成电流信号，通过井下参数测量装置、潜油电机、地面仪表以及潜油电泵壳体传输到地面。通过一个模拟井下高温、高压、强振动环境的信号传输实验证明了该传输电路的可行性以及信号传输的精度, 井下的传输信号与井上提取到的信号的包络线保持一致并且经过数字滤波后误差率低于0.1%。

本文利用等电势原理设计了一种井下参数测量装置远程供电系统，文中首先对等电势原理进行了介绍，通过地面三相电抗器，供电系统提供的直流电可以为井下测量装置远程供电。文中对地面供电系统电路进行了设计，系统的主体是较宽输入电压范围内都能保持稳定输出的反激变换电路，实验证明其电压调整率为0.36%，负载调整率为0.42%，均满足设计要求。