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关键词： PLC   PID   变频器   恒压供水系统  

摘要： 采用PLC和变频器相结合设计恒压供水系统,采集管网的水压力,经A/D转换后送入PLC,经PLC的PID运算后输出信号来控制变频器的输出电压和频率,改变电动机的转速来改变供水量,最终使管网水压力值稳定在恒定值。实践证明,该系统稳定可靠,同时还具有良好的节能效果。

关键词： 抽水蓄能   静止变频器   无位置传感器   逆变器   低速阶段  

摘要： 针对抽水蓄能静止变频器低速起动阶段机端电压小且畸变严重的情况,提出了一种基于机组起动恒定加速度的无位置传感器起动的开环控制方法。通过理论推导,计算出静止变频低速起动阶段逆变器各强迫换相点时刻,使转子转速平滑的上升。最终,通过试验验证其在抽水蓄能机组中的可行性,并为实际操作提供了一定的理论指导。

关键词： 能力差异   转型升级   智能制造   企业年报   制造业   财报   年度报告   变频器  

摘要： 随着制造业的转型升级,对自动化和智能制造设备的需求不断增加。作为自动化和智能制造设备的核心部件,变频器的市场需求随之增长。近期,变频器上市企业陆续公布了2023年度报告。过去一年,全球经济形势复杂多变,各种不确定性大大增加,变频器作为制造业的重要组成部分,其发展状况备受关注。从各家企业公布的2023年度财报看,不少企业业绩实现了增长,也有企业业绩出现了下滑,各企业之间的盈利能力差异愈发显著。

关键词： 直接转矩控制   变论域   自适应模糊控制   模型参考自适应   自耦PI  

摘要： 文章针对传统无速度传感器直接转矩控制转速不稳定、超调量大等问题做出两点改进。首先,引入自耦PI对传统MRAS无速度传感器直接转矩控制进行改进,该方法改善无传感器直接转矩控制调速性能、降低超调量、减小稳态误差;其次,针对直接转矩控制具有转矩脉动大、调速性能差等缺点,提出变论域静态模糊自适应PI控制策略,减小转矩脉动并改善调速性能,大大提升了抗负载能力;最后,在Matlab/Simulink仿真环境下进行了仿真并进行分析,证明了上述方法的有效性和可行性。结果表明,相对于传统的无速度传感器直接转矩控制系统,仿真结果显示减小了转速超调量,缩短了转速上升中到达高速工况的响应时间,提升了抗负载能力。

关键词： RC-IGBT   Super junction   Pinch-off   Carrier accumulation  

摘要： A Reverse Conduction Insulated Gate Bipolar Transistor (RC-IGBT) featuring an Active Trench Barrier (ATB) based on Super-Junction (SJ) technology is proposed and investigated. The double-trench gates are designed at the N-pillar and P-pillar of the SJ drift. Consequently, a p-type ATB located between the two trench gates is formed. The ATB working mechanism is controlled and modulated by the Gate Voltage (VGE) of the double-trench gates. In the forward conduction state, the ATB channel is depleted and automatically pinched off by the positive VGE. Thus, the barrier potential of the ATB is remarkably improved. Additionally, holes accumulate underneath the ATB and maintain high conductivity modulation of the SJ drift region. Thus, the low on-state voltage drop (VON) is obtained. In the reverse conduction state, the ATB pinch-off effect automatically fades away with the grounded VGE. In addition, the ATB, P-pillar, and N + act as the anode, drift, and cathode of the Free-Wheeling Diode (FWD), respectively. Electrons are blocked and accumulated by the trench gates. Thus, the hole injection is enhanced and the reverse conduction voltage (VR) is reduced. In the turn-off state, excessive holes can be effectively extracted by the extra ATB channel, and the turn-off loss (EOFF) is remarkably decreased. As a result, the trade-off relationship between VON and EOFF can be significantly improved, which achieves the best comprehensive property when compared with the conventional RC-IGBT and SJ-IGBT.

关键词： Condition monitoring  

摘要： This paper presents a power-cycling degradation monitoring method of an IGBT module with a VCE(sat) sensing circuit and junction temperature prediction by a three-dimensional structure model. A chopper circuit was introduced to provide a continuous-current-conducting operation of the IGBT module. The VCE(sat) sensing circuit with a low-cost IoT platform "Leafony" was utilized to monitor the junction temperature of an IGBT chip, which transferred the measured signal as digital data, and thus obtained a higher noise immunity than an analog-based circuit. The junction temperature of IGBT chip in the power module was analyzed from the dissipated power of IGBT and the transient thermal impedance between the chips and the ambient. This analysis is effective not only to observe the degradation but also to estimate the thermal resistance. Comparing the temperature profile between experiment and prediction provides health condition of the IGBT model. Predicted thermal profiles agreed with measured ones with 10 % increase of thermal resistance, which was degraded by a power cycle tester. From these results, the proposed monitoring method is effective to detect the progress of power cycle degradation. © 2024 The Author(s)

关键词： Aging   Insulated gate bipolar transistors   Temperature   Insulation   Silicon   Absorption   Partial discharges   Breakdown voltage   crosslinking density   dielectric constant   silicone gel   thermal aging  

摘要： Due to power loss, the internal junction temperature of insulated gate bipolar junction transistor (IGBT) devices increases. Long-term operation in the environment of high junction temperature will lead to the aging of silicone gel, the insulating packaging material for IGBT devices. Its electrical property will decline after aging, which will directly affect its service life. However, its impact law and mechanism are still unclear. For this reason, this article focuses on the accelerated thermal-oxidative aging of silicone gel materials to carry out experimental research. Combined with Fourier transform infrared spectrometer (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and other analytical means to observe the microstructure of silicone gel in different aging stages, we explore the changes in its electrical property and analyze the mechanism of thermal aging on its insulation performance. The results show that the side chain oxidative crosslinking reaction mainly occurred after aging, and the degree of side chain crosslinking increased with the increasing degree of aging. The free volume of silicone gel increased after aging, the average free travel of electrons increased, and the breakdown voltage decreased. Due to the side chain oxidative cross-linking reaction, the molecular chain structure became neater, the polarity was weakened, and it was more difficult to polarize under the external electric field, which made its real part of relative complex relative permittivity decline, the dielectric loss increased at the same time, and the insulation performance became worse. The experimental results of this article can provide a certain theoretical basis for the evaluation of IGBT insulation status.

关键词： 最佳控制  

ISBN: (纸本)9787302656449

关键词： Insulated gate bipolar transistors (IGBT)  

摘要： This paper reports the mechanism of gate voltage spike in the turn-off operation by a digital gate control. In the previous work, it was clarified that the gate voltage spike Vg_spike was generated by parasitic inductance and a large gate current change due to the digital gate control. However, the main cause of resonance leading to Vg_spike generation has never been clear. Three types of IGBT modules, which have the same gate inductance and different input capacitance, were tested under three-step digital gate control. It was found that the Vg_spike was independent of input capacitance in IGBT. As for the stray capacitance in the digital gate driver, external capacitors Cex were connected in parallel with the gate driver, and the Vg_spike decreased with increasing Cex. Furthermore, the second vector of the digital control, which was applied for suppressing the overshoot in collector-emitter voltage by a small value, needed to be set as a large value to suppress the Vg_spike. From these results, output impedance of gate driver is a key factor for the Vg_spike, and the second vector must be optimized for not only the collector voltage overshoot but also Vg_spike suppression for safety operation. © 2023 The Authors

关键词： Displacement current   electromagnetic interference (EMI) noise   insulated gate bipolar transistor (IGBT)   miller capacitance   polysilicon gate structure  

摘要： In this article, an innovative 1200 V insulated gate bipolar transistor (IGBT) is proposed with N-P-N three polysilicon layers staked gate (PG) structure. This novel gate structure can be feasibly manufactured, which is constituted by two polysilicon diodes (PDs) connected in common anode. Then, the inventive charging mechanism of the PG structure at blocking state provides higher breakdown voltage (BV) due to the lateral electrical field by the N- polysilicon depleted region. While the PD2 depleted region contributes to reducing the Miller capacitance ( C-res) and charging up the trench bottom potential higher before turn on process, it weakens the hole carrier accumulation and further suppresses the displacement current to the gate during the turn on period. Investigated by the TCAD tools, the proposed IGBT shows 16.9% reduced Cres and better E-off - V-CEon tradeoff (17.3%) compared with the conventional IGBT. Besides that, the proposed IGBT also indicates 49.0% decline on the surge current and 63.4% decline on the dV(KA)/dt(max) of the free-wheeling diode (FWD) for 30 mJ turn on energy loss ( E-on) compared with the conventional IGBT, which demonstrates lower Electromagnetic interference (EMI) noise. Finally, the proposed IGBT features wider borders of the RBSOA and SCSOA, which guarantees the robustness of this novel gate structure.