共查询到20条相似文献,搜索用时 15 毫秒
1.
In this paper, a novel three-phase, DC/AC converter suitable for distributed power applications is proposed. The system consists of three DC/DC boost converters with a common point and operating as a three-phase inverter with intrinsic step-up capability. The converter obtained can invert, amplify and, where possible, regenerate bidirectional power sources such as fuel-cells, small gas turbines, and photovoltaic arrays. There are two main advantages to the system: the use of only six insulated gate bipolar transistors and small passive elements, and the fact that it does not need reverse voltage blocking capability. Simulation and experimental results show the effectiveness of the proposed system during both steady-state and dynamic operations. 相似文献
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An analogue linearising pulsewidth modulator (LPWM) for a three-phase boost inverter is presented. It employs integrators with hold and reset to compute the switching instants. The LPWM enables the output voltages of the boost inverter, which are nonlinear with respect to duty ratio control, to track the control voltages linearly. The theory is verified by experimental data 相似文献
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The discrete-time control of a three-phase inverter with an output LC filter is described based on space vectors. The mathematical model of the inverter-filter system is first obtained by using space vectors to represent three-phase quantities. Deadbeat control laws are derived for no-load and resistive-load cases. Then, a deadbeat control law is obtained for the case when the load draws current of any waveshape from the inverter-filter. It is shown that deadbeat control of output voltage can be achieved in two control steps. The manipulated variable, which is the voltage vector demanded from the inverter, is implemented using the space vector modulation technique. Simulation results for various operating conditions are presented 相似文献
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A novel feedback current controller for a three-phase load driven by a power inverter is proposed. The main design specifications are robustness to load electrical parameters, fast dynamical response, reduced switching frequency, and simple hardware implementation. To meet previous specifications a multi-variable hysteresis type controller is proposed, designed as a finite-state automaton and implemented with a programmable logic device. After a general introduction, system analysis is performed, control targets are specified, and the proposed control strategy is presented and discussed. Further, actual controller architecture, based on simple analog-logic hardware, is shown and experimental results are presented using an induction motor as the inverter load. However, this does not limit the wider applicability of the proposed controller that is suitable for different types of three-phase AC loads 相似文献
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Hurng-Liahng Jou Jinn-Chang Wu Kuen-Der Wu Hong-Ren Shen 《International Journal of Electronics》2018,105(11):1962-1975
A conventional DC-AC inverter can only output either a single-phase AC voltage or a set of three-phase AC voltages. A new three-port DC-AC inverter which can simultaneously output a single-phase AC voltage and a set of three-phase AC voltages is proposed in this paper. This three-port DC-AC inverter is based on the three-port T-type multi-level power converter which is composed of three T-type power electronic legs, a decoupling transformer set, a filter inductor set, a single-phase filter capacitor, and a three-phase filter capacitor set. The DC port of the proposed power converter is connected to a DC power source to act as the input port, and the single-phase AC port and the three-phase AC port serve as two output ports to supply power to the single-phase load and the three-phase load, respectively. The zero-sequence transformer is used to decouple the single-phase and three-phase AC components, which are generated by the three T-type power electronic legs. The operation principle of this three-port DC-AC inverter is analyzed, and a hardware prototype is established to verify the performance of the proposed three-port DC-AC inverter. The experimental results are as expected. 相似文献
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本文从二极管箝位型三电平逆变器的基本结构出发,分析其输出状态,推导出六角形空间电压矢量图。然后从一种改进的,可以减小开关损耗,避免高的dv/dt三电平空间矢量PWM调制策略出发,建立了基于Matlab的详细仿真方案,验证了方案的可行性。文章给出了扇区判断的算法流程图,脉冲生成模块的内部结构图,其中的扇区判断的算法和脉冲生成方法对于用DSP实现三电平SVPWM具有重要的参考价值。 相似文献
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In this article, a high-speed electro-thermal (ET) modelling strategy to predict the junction temperature of insulated gate bipolar transistor (IGBT) devices of a three-phase inverter power module is presented. The temperature-dependent power loss characteristics of IGBT and diode devices are measured and stored in lookup tables, which replace the conventional complicated physics-based compact models. An inverter is modelled as a voltage controlled voltage source, which allows the inverter-based power train simulation to be carried out in the continuous time domain with a large simulation time-step (1 ms). Using the simulated sinusoidal voltage and current components of the inverter output, the given pulse width modulation mode, the conduction time (duty ratio) and the current of the devices are extracted. Based on the lookup tables, on-times and conduction currents of devices, the average power loss over each simulation time-step is calculated, which is then fed into the inverter thermal model to predict the devices' temperatures. The advantage of the proposed model is that an accurate ET simulation of inverter for long real-time (many minutes) operation can be carried out within an acceptable computational time using a standard modern personal computer. Both simulation and experimental validation have been carried out, and an excellent agreement has been achieved between the simulation and experimental data. 相似文献
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ABSTRACT In order to realise the energy-saving operation of the three-phase inverter, a three-phase resonant DC link inverter with soft-switching function is proposed. The auxiliary resonant circuit on the DC side participates in the commutation process, so that the DC link voltage can change to zero before the main switch on the bridge arm is switched. Therefore, the main switch can complete the zero-voltage soft-switching and realise the energy-saving operation of the inverter by reducing the switching power loss. The circuit workflow and parameter design rules in each switching period are analysed. As indicated from the experimental results, the switching device is in the soft-switching state when it is switched, and when the output power reaches the rated value of 2.5 kW, the efficiency of the prototype is 98.4%, which is higher than that of the same type of soft-switching inverters. Thus, the auxiliary resonant circuit structure has reference value for the research and development of energy-saving three-phase inverters. 相似文献
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Keliang Zhou Danwei Wang 《Electronics letters》2000,36(10):864-865
A zero tracking error control scheme for three-phase CVCF PWM inverters is proposed. The proposed scheme uses repetitive controller (RC) to force output line voltages to track a sinusoidal reference signal with zero error. Minimised voltage distortion and a fast response are obtained. The validity of the proposed scheme has been verified by simulations 相似文献
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A microprocessor-controlled PWM (pulse-width-modulated) inverter has been developed in which the neutral point at a star-connected load is clamped in potential. In addition to PWM waveforms, the inverter can generate six-step or eight-step waveforms in response to the appropriate software, using the MC68000 microprocessor. Operation takes places in the PWM model for 1-40 Hz and in a step mode for 40-100 Hz. The inverter used 12 power switches compared with the customary six switches in a standard inverter. Darlington power transistors were used in a laboratory prototype rated at 6 kW. A design feature is that power to the drive circuits of the twelve switches come directly from the DC supply, eliminating the need for individual power supplies. The root-mean-square value of the fundamental line voltage is 0.64 V DC compared to 0.5 V DC for conventional PWM operation with a six-switch inverter 相似文献
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A simplified three-phase zero-current-transition inverter with three auxiliary switches 总被引:2,自引:0,他引:2
Most existing three-phase soft-switching inverters with fewer than six auxiliary switches have fundamental drawbacks in performance. There exist a few soft-switching inverters with six auxiliary switches that can potentially achieve desirable performance, but are penalized with the high cost and large size associated with the auxiliary switches. This paper proposes a zero-current-transition (ZCT) inverter topology that requires only three auxiliary switches. Each phase of the proposed circuit employs one auxiliary switch and one LC resonant tank to assist switching transitions. With considerable reduction in device count, cost, and size, the proposed topology realizes zero-current turn-off for all main switches and auxiliary switches, and provides soft commutation for all diodes. Meanwhile, it requires no modification to normal pulsewidth modulated (PWM) algorithms. The operation principles, design and control guidelines, and an analysis using the state-plane technique are presented. Based on the proposed topology, a 50-kW three-phase prototype inverter has been developed for electric vehicle propulsions, and tested to the full power level with a closed-loop induction motor drive system. Experimental results on the 50-kW prototype are provided to verify the proposed concept in high-power AC adjustable speed drive applications. 相似文献
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三相SPWM逆变器的调制建模和仿真 总被引:1,自引:0,他引:1
简单介绍了三相SPWM逆变器的组成和工作原理,通过计算机对三相SPWM逆变器进行Matlab/Simulink建模和仿真,研究逆变电路的输入输出及其特性。仿真分析经逆变后得到的电压电流的特性。通过运用Matlab/Simulink和Power System Block(PSB)电力系统模块集工具箱仿真环境,对电路进行建模、计算和仿真分析。MATLAB软件中的Simulink,是为数不多的完全满足这些条件和要求的软件。并且凭借他在科学计算方面的天然优势建立了从设计构思到最终实现设计要求的可视化桥梁。被广泛应用于线性系统、非线性系统及数字信号处理的建模和仿真中。 相似文献
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Grid current regulation of a three-phase voltage source inverter with an LCL input filter 总被引:16,自引:0,他引:16
Many grid connected power electronic systems, such as STATCOMs, UPFCs, and distributed generation system interfaces, use a voltage source inverter (VSI) connected to the supply network through a filter. This filter, typically a series inductance, acts to reduce the switching harmonics entering the distribution network. An alternative filter is a LCL network, which can achieve reduced levels of harmonic distortion at lower switching frequencies and with less inductance, and therefore has potential benefits for higher power applications. However, systems incorporating LCL filters require more complex control strategies and are not commonly presented in literature. This paper proposes a robust strategy for regulating the grid current entering a distribution network from a three-phase VSI system connected via a LCL filter. The strategy integrates an outer loop grid current regulator with inner capacitor current regulation to stabilize the system. A synchronous frame PI current regulation strategy is used for the outer grid current control loop. Linear analysis, simulation, and experimental results are used to verify the stability of the control algorithm across a range of operating conditions. Finally, expressions for ""harmonic impedance" of the system are derived to study the effects of supply voltage distortion on the harmonic performance of the system. 相似文献
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This paper proposes a new soft-transition control strategy for a three-phase zero-current-transition (ZCT) inverter circuit. Each phase leg of the inverter circuit consists of an LC resonant tank, two main switches, and two auxiliary switches. The proposed strategy is realized by planning the switching patterns and timings of these four switches based on the load current information. It enables all the main switches and auxiliary switches to be turned on and turned off under zero-current conditions, and achieves a near zero-voltage turn-on for the main switches. Compared with existing ZCT strategies, the diode reverse recovery current and switching turn-on loss are substantially reduced, the current and thermal stresses in the auxiliary devices are evenly distributed over every switching cycle, and the resonant capacitor voltage stress is reduced from twice the DC bus voltage to 1.3-1.4 times the DC bus voltage. The proposed strategy is also suitable for three-phase power-factor-correction (PFC) rectifier applications. The operation principles, including a detailed analyst based on the state-plane technique, and a design rule are described in this paper. The circuit operation is first verified by a computer simulation, and is then tested with a 50-kW three-phase inverter to the full power level together with a three-phase induction motor in a closed-loop speed/torque control. Significant reductions in switching losses and voltage/current stresses over existing techniques have been experimentally demonstrated 相似文献
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The design of three-phase pulse-width-modulated (PWM) inverters requires values for the average and RMS currents in the inverter in order to select the right components. A computer-aided investigation of approximate inverter current waveforms indicates that the average and RMS inverter currents are simple functions of a single factor equal to the product of the power factor and the modulation index. These functions are expressed as per-unit equations that are useful not only for designing new inverters, but also for evaluating existing designs 相似文献
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A two-level four-leg inverter has been developed for the three-phase four-wire power quality compensators. When it is applied to medium and large capacity compensators, the voltage stress across each switch is so high that the corresponding dv/dt causes large electromagnetic interference. The multilevel voltage source inverter topologies are good substitutes, since they can reduce voltage stress and improves output harmonic contents. The existing three-level neutral point clamped (NPC) inverter in three-phase three-wire systems can be used in three-phase four-wire systems also, because the split dc capacitors provide a neutral connection. This paper presents a comparison study between the three-level four-leg NPC inverter and the three-level NPC inverter. A fast and generalized applicable three-dimensional space vector modulation (3DSVM) is proposed for controlling a three-level NPC inverter in a three-phase four-wire system. The zero-sequence component of each vector is considered in order to implement the neutral current compensation. Both simulation and experimental results are given to show the effectiveness of the proposed 3DSVM control strategy. Comparisons between the 3DSVM and the 3-D hysteresis control strategy are also achieved. 相似文献