基于SG3525控制的车载逆变电源设计

介绍一种基于SG3525控制的车载逆变电源的工作原理和电路设计.主电路采用典型两级变换的逆变结构:第1级变换通过SG3525控制器产生高频脉冲宽带调制(PWM)波,对输入信号升压整流;第2级变换通过NE556和CD4013芯片搭建逆变控制电路,将直流信号变换成工频信号;设计电池过压、欠压,输出过流、过热和输出欠压等保护电路.经验证该逆变电源具有可靠性高、电路简单、体积小等优点.     

晶体管式精密电阻点焊电源的设计

为满足微型零件焊接对焊接能量精密性、快速性和稳定性的要求,设计了一种高频晶体管式电阻点焊电源。电源包含半桥逆变恒流充电部分和高频斩波输出部分,逆变频率为100 k Hz,通过脉冲宽度调制(Pulse Width Modulation,PWM)和增量式比例积分微分(Proportion Integration Differentiation,PID)控制技术,实现了电容组恒流快速充电;斩波频率为100 k Hz,大大提高了焊接输出能量调节响应速度和控制精度。试验结果表明,电容组最大充电电流为100 A,充电电压为30 V,充电时间小于100 ms;电源具有恒电流、恒电压和恒功率输出模式,焊接电流上升速度达到50 A/μs,放电脉冲可在1 ms内实现稳定输出,实际焊接效果良好,在精密焊接中具有明显优势。     

Advanced control of grid-connected inverters for proton exchange membrane fuel cell system

Voltage support is one of the most important issues for operating grid-connected inverters under grid faults. Many control strategies have been addressed in literature, but most of them focus on the voltage support control without considering issues of power quality due to voltage harmonics. In order to sort out the drawback, a novel advanced control strategy is presented in this paper. It is able to provide the voltage support function. Meanwhile, the power quality is improved by regulating the control coefficients. The time-domain simulation and experimental results are provided to evaluate the conventional and proposed control strategies. The results show that the total harmonic distortion of PCC voltage can be reduced from 9.35% to 2.88% with the proposed solution. Meanwhile, the voltage support is also achieved, which verify the effectiveness of the proposed solution.     

Bidirectional energy storage photovoltaic grid-connected inverter application system

A novel topology of the bidirectional energy storage photovoltaic grid-connected inverter was proposed to reduce the negative impact of the photovoltaic grid-connected system on the grid caused by environmental instability. Using the proposed Inverter as a UPS power supply in case of a grid failure, storage electrical energy and regulating the energy delivered to the grid for reducing the pressure on the grid. A new artificial fish-swarm algorithm and variable step voltage perturbation method were presented to track the maximum power point of the solar panels. Analysis was done to reduce the output ripple of the inverter and sinusoidal pulse width modulation (SPWM) was selected to control the inverter. Model simulation was performed using PSpice software to obtain the volt-ampere characteristic curve of the solar panel output. The solar array simulator was used to verify the effect of maximum power point tracking at different light intensities. The study concludes that the maximum power point tracking (MPPT) efficiency of the bidirectional energy storage photovoltaic grid-connected inverter designed was as high as 99.9%. The distortion rate of the grid-connected current waveform was within 2% and the DC current component was less than 0.5%. The output voltage and power were in full compliance with the grid connection standard.     

Assessing Cloud Transient Impacts of Solar and Battery Energy Systems on Grid Inertial Responses

To assess the dynamic impact of intermittency of rapidly increasing solar photovoltaic generation on the grid, this article presents the modeling and integration of the components that need to be considered, including the solar photovoltaic plant, battery energy storage system, grid-tied interface, and associated control systems. The complexity and accuracy of these models are suitable for evaluating the transient impact on bulk power systems. Of particular interest is the grid inertial response in such situations as different penetration levels of solar generation and fast cloud transient induced solar generation decrease coupled with outages that recurrently occur in the grid, e.g., a generator trip. The impact of such events on the grid frequency responses is investigated using a simplified simulation approach to account for the locational or spatial irradiance variation patterns and cloud movements. Responsive battery energy storage systems are recognized as an effective means to improve the inertial response.     

Direct torque control of doubly fedinduction motor using three-level NPCinverter

This article presents the direct torque control (DTC) strategy for the doubly fed induction motor (DFIM) connected to two three-level voltage source inverters (3LVSIs) with neutral point clamped (NPC) structure. This control method allows to reduce the torque and flux ripples as well as to optimize the total harmonic distortion (THD) of motor currents. The use of 3LVSI increases the number of generated voltage, which allows improving the quality of its waveform and thus improves the DTC strategy. The system modeling and control are implemented in Matlab/ Simulink environment. The analysis of simulation results shows the better performances of this control, especially in terms of torque and flux behavior, compared to conventional DTC.     

数据可视化的LCL型并网逆变器PI参数设计

为了清楚的在全局范围内展开比例积分(PI)的设计参数与设计效果的因果关系,提出一种基于LCL型单相并网逆变器的PI数据可视化设计。根据系统的稳定性、系统频域和时域的性能指标,利用Matlab得出最优PI参数的可视化数据区域,此设计方法简单、快速,无需反复试凑。在实验室设计一台3 kW的原理样机验证该理论的正确性。实验结果表明,基于数据可视化设计的PI参数,单相LCL型电流并网系统具有良好的跟踪特性和抗干扰特性,实现高的功率因数并网,系统具有良好的动静态性能。