光伏并网逆变器-毕业论文外文翻译.doc

1、外文资料翻译 译文：光伏并网逆变器最近，人们越来越关注的替代能源，因为化石燃料和核电厂的环境影响及其稳定性(长尾和原田，1997年;Myrzlk, 2001年)。在各种替代能源屮，太阳能发电尤为重视， 除了因为它是一种淸洁的，无限的能源，此外相当多的研宄己经在这一领域取得了突出 的成绩。太阳能发电系统由太阳电池组件，充电电池，和一个逆变器。现在只有逆变电 流模式进入主流，原因是光伏逆变是正弦电流进入电网。具体体现在单相并网光伏逆变 器屮，它具有普遍的拓扑结构，这是标准的全桥电压源逆变器(电平逆变器)，它可以 创建一个正弦电网电流(Kjaeret al” 2005; Kojabadi et al

2、.，2006)。这种拓扑结构有两个普遍的问题如下。(1 )电池是太阳能发电厂必不可少的储存电能设备。但电池充电是一个短期和有污染 的过程，并且有负面经济的效率。然而，逆变器可以不使用电池可以解决这些问题。在 这个过程屮，接口电路为逆变环节的直流电(DC)输出的太阳能电池阵列的交流电源 系统。如果输出电压的电流源逆变低于电力系统电压和在发生短路负荷或逆变器故障, 它没有电流短路(Myrzlk, 2001年)。(2)在一般的微处理器作为控制器，以实现良好的特点时，太阳能发电系统与电流源 逆变器的设计。是在控制器以较少的价值，有高质量电感和电波的输出电流的高开关频 率变频器所需要的，但是，受限制的是

3、开关损耗和处理器的采样频率。图.1显示的结构电流源逆变器用作接门电路连接太阳能电池的实用线(Mohan etal, 1995 年)。它由五个开关，一个电感器，LC滤波器，输出端门。逆变器工作在这两个开关 模式。质量保证开关只执行斩波行动，而第一季度，第四季度交换机确定方向的输出电 压根据极性的电力系统。因此，与一般全桥PWM逆变器执行完整的一块，该系统减少 了开关损耗。+heToot图.2显示波形的传统电流源逆变器。它代表了波形的输出电压和电流，该电流通过 电感，输入信号，每个开关。18 H 0,0,OQ.图.3显示了脉冲转变电流源逆变器电路，用于降低开关频率和提高效率。当太阳能 电池模块输出

4、电压的是高于或低于输出电压的转换器，则合成的电流源转换，这需要 Buck-Boost变换器运作良好。电路降压频率的逆变器是固定的，在60HZ，这是电力系统频率。该过滤器(LS，CS)在输出端门的逆变器是一种低成本的能力，以改善波形 的输出电流。如果过滤器的高容量的使用，功率因数的系统将不统一，因为相位延迟。lx图.4显示波形是电流源逆变器。指标代表交换期间的升压斩波器，这个数字。国际 法协会，ILF代表波形电感电流各自的转换和IDC代表输出电流的逆变器。作为一个脉 冲波形，输出波形的六脉冲移转换代表6波形开关频率TS.We采用了数字信号处理器 (TMS320F2812 )产生的PWM 6相移信

5、号电流源逆变本文。由于采用非对称PWM模 式，波形的输出电流，这儿乎是逆变器的波形相似，六乘以开关频率但不完全相同的。ii氤Ti /V71八-itAtt7斤，i2zkk k rk k kigr图.5显示了各自的电感电流和输出电流的常规逆变器和逆变器相等的开关频率。Qaim脚nmm ra a原文:Grid-connected photovoltaic system using current-source inverterRecently, there has been a growing interest in alternative energy sources because fossil

6、 fu el and atomic power plants affect the environment and its stability (Nagao and Harada，1997; Myrzlk，2001). Among the various alternative source of energy，solar power stands apart as it i s a clean and unlimited source of energy moreover，a considerable amount of research has bee n conducted recent

7、ly in this field. A solar power system consists of a photovoltaic module,a c harge battery, and an inverter. Only inverters operating in current-source mode are included in the classification,since one of the aims of the PV inverter is to inject a sinusoidal current into the grid. To embody the oper

8、ation of a single-phase-grid-connected inverter for photovoltaic module，it has general topology that is a standard full-bridge voltage source inverter (VSI)，wh ich can create a sinusoidal grid current (Kjaer et al.，2005; Kojabadi et al.，2006). This topolog y has two general problem as below.(1) A ba

9、ttery is essential to store the electric energy generated by a solar power plant. But a ch arge battery has problems on its a short duration and pollution along with economic efficienc y. However, transmitting the generated energy directly into the utility line without using a batt ery can solve the

10、se problems. In this process，an interface circuit called an inverter links the di rect current (DC) output from the solar cell array to the AC power system. It does not matter if the output voltage of the current-source-inverter is lower than the power system voltage and i n case of a shorted load o

11、r inverter malfunction, it does not have a surge current from a short- circuit (Myrzlk，2001).(2) In general a microprocessor is used as the controller to achieve good characteristics when designing solar power systems with the current-source-inverters. In the controller, to reduce th e value of the

12、inductance and the ripple of the output current，a high switching frequency is re quired for the inverter，however，the frequency is restricted by the switching loss and samplin g frequency of a processor.Fig. 1 shows the structure of a current-source PWM inverter used as the interface circuit for li n

13、king solar cells to the utility line (Mohan et al.，1995). It consists of fiveswitches，one induct or, and an LC filter at the output port. This inverter operates in two switching modes. The QA switch only performs the chopping action, while the Ql-Q4 switches determine the directions of the output vo

14、ltage according to the polarity of the po wer system. Therefore，compared with general full-bridge PWMinverter that performs comple te chopping, this system reduces the switching loss.lxFig. 2 shows the waveforms of the conventional current-source PWM inverter. It represents th e waveforms of the out

15、put voltage and current, the current through the inductor，and the input signals to each switch.Fig. 3 shows the proposed six-pulse-shift current-source PWM inverter circuit that is used to r educe the switching frequency and improve the efficiency. Whenever the output voltage of solar cell module is

16、 higher or lower than the output voltage of the converter in compositing the c urrent-source converter，it is required that the buck-boost converter operate well. The propose d circuit has buck-frequency of the inverter is fixed at 60 Hz, which is the value of power sy stem frequency. The filter (LS，

17、CS) at the output port of the inverter is of a low capacity to im prove the waveform of the output current. If a high capacity filter were to be used，the power f actor of the system would not be unity because of the phase delay.lxFig. 4 shows the waveforms of the proposed current source PWM inverter

18、. TS represents the s witching period of the buck-boost choppers in this figure. ILA-ILF represent the waveforms of the inductor currents of the respective converters and IDC rep resents the output current of the inverter. As a operational waveform, the output waveform of six-pulse-shift the convert

19、er represent six waveform in switching frequency TS.We used a DS P (TMS320F2812) to generate a PWM six-phase-shift signal for the current-source inverter in this paper. As a result of using the asymmetricPWM mode，the waveform of the output curren t of this inverter is almost similar to the waveform on six multiplied switching frequency but n ot exactly the same.Fig. 5 shows the respective inductor currents and output current of a conventional inverter and the proposed inverter at equal switching frequencies.