光伏发电系统外文翻译光伏发电系统的新型控制方案.docx

1、光伏发电系统外文翻译光伏发电系统的新型控制方案英文1300单词，7000英文字符，中文2150汉字出处：Khatib T T N, Mohamed A, Amin N. A new controller scheme for photovoltaics power generation systemsJ. European Journal of Scientific Research, 2009, 33(3): 515-524.外文文献：A New Controller Scheme for Photovoltaics Power Generation SystemsKhatib T T N,

2、 Mohamed A, Amin NAbstractThis paper presents a new controller scheme for photovoltaic (PV) power generation systems. The proposed PV controller scheme controls both the boost converter and the battery charger by using a microcontroller in order to extract maximum power from the PV array and control

3、 the charging process of the battery. The objective of the paper is to present a cost effective boost converter design and an improved maximum power point tracking algorithm for the PV system. A MATLAB based simulation model of the proposed standalone PV system has been developed to evaluate the fea

4、sibility of the system in ensuring maximum power point operation.1.IntroductionRecently, the installation of PV generation systems is rapidly growing due to concerns related to environment, global warming, energy security, technology improvements and decreasing costs. PV generation system is conside

5、red as a clean and environmentally-friendly source of energy. The main applications of PV systems are in either standalone or grid connected configurations. Standalone PV generation systems are attractive as indispensable electricity source for remote areas. However, PV generation systems have two m

6、ajor problems which are related to low conversion efficiency of about 9 to 12 % especially in low irradiation conditions and the amount of electric power generated by PV arrays varies continuously with weather conditions. Therefore, many research works are done to increase the efficiency of the ener

7、gy produced from the PV arrays.The solar cell V-I characteristics is nonlinear and varies with irradiation and temperature. But there is a unique point on the V-I and P-V curves, called as the maximum power point (MPP), at which at this point the PV system is said to operate with maximum efficiency

8、and produces its maximum power output. The location of the MPP is not known but can be traced by either through calculation models or search algorithms. Thus, maximum power point tracking (MPPT) techniques are needed to maintain the PV arrays operating point at its MPP. Many MPPT techniques have bee

9、n proposed in the literature in which the techniques vary in many aspects, including simplicity, convergence speed, hardware implementation and range of effectiveness. However, the most widely used MPPT technique is the perturbation and observation (P&O) method. This paper presents a simple MPPT alg

10、orithm which can be easily implemented and adopted for low cost PV applications. The objective of this paper is to design a novel PV controller scheme with improved MPPT method.The proposed standalone PV controller implementation takes into account mathematical model of each component as well as act

11、ual component specification. The dcdc or boost converter is the front-end component connected between the PV array and the load. The conventional boost converter may cause serious reverse recovery problem and increase the rating of all devices. As a result, the conversion efficiency is degraded and

12、the electromagnetic interference problem becomes severe under this situation. To increase the conversion efficiency, many modified step-up converter topologies have been investigated by several researchers. Voltage clamped techniques have been incorporated in the converter design to overcome the sev

13、ere reverse-recovery problem of the output diodes. In this paper, focus is also given in the boost converter design. Another important component in the standalone PV systems is the charge controller which is used to save the battery from possible damage due to over-charging and over-discharging. Stu

14、dies showed that the life time of a battery can be degraded without using a charge controller.The proposed new controller scheme for the standalone PV system controls both the boost converter and the charge controller in two control steps. The first step is to control the boost converter so as to ex

15、tract the maximum power point of the PV modules. Here, a high step-up converter is considered for the purpose of stepping up the PV voltage and consequently reducing the number of series-connected PV modules and to maintain a constant dc bus voltage. A microcontroller is used for data acquisition th

16、at gets PV module operating current and voltage and is also used to program the MPPT algorithm. The controller adopts the pulse width modulation (PWM) technique to increase the duty cycle of the generated pulses as the PV voltage decreases so as to obtain a stable output voltage and current close to

17、 the maximum power point. The second control step is to control the charge controller for the purpose of protecting the batteries. By controlling the charging current using the PWM technique and controlling the battery voltage during charging, voltages higher than the gassing voltage can be avoided.

18、2. Design of the Proposed Photovoltaic SystemMost of the standalone PV systems operate in one mode only such that the PV system charges the battery which in turns supply power to the load. In this mode of operation, the life cycle time of the battery may be reduced due to continuous charging and dis

19、charging of the battery. The proposed standalone PV system as shown in terms of a block diagram in Figure 1 is designed to operate in two modes: PV system supplies power directly to loads and when the radiation goes down and the produced energy is not enough, the PV system will charge the battery wh

20、ich in turns supply power to the load. To manage these modes of operation, a controller is connected to the boost converter by observing the PV output power.3. MethodologyFor the purpose of estimating the mathematical models developed for the proposed standalone PV system, simulations were carried i

21、n terms of the MATLAB codes. Each PV module considered in the simulation has a rating of 80 Watt at 1000 W/m2, 21.2 V open circuit voltage, 5A short circuit current. The PV module is connected to a block of batteries with of sizing 60 Ah, 48 V. 4. Results and DiscussionThe simulation results of the

22、standalone PV system using a simple MPPT algorithm and an improved boost converter design are described in this section. Simulations were carried out for the PV system operating above 30o C ambient temperature and under different values of irradiation. Figure 2 shows the PV array I-V characteristic

23、curve at various irradiation values. From the figure, it is observed that the PV current increase linearly as the irradiation value is increased. However, the PV voltage increases in logarithmic pattern as the irradiation increases. Figure 3 shows the PV array I-V characteristic curve at various tem

24、perature values. It is noted from the figure that, the PV voltage decreases as the ambient temperature is increased.Figure 4 compares the PV array P-V characteristics obtained from using the proposed MPPT algorithm and the classical MPPT P&O algorithm. From this figure, it can be seen that by using

25、the proposed MPPT algorithm, the operating point of PV array is much closer to the MPP compared to the using the classical P&O algorithm.In addition, the proposed boost converter is able to give a stable output voltage as shown in Figure 5. In terms of PV array current, it can be seen from Figure 6

26、that the PV current is closer to the MPP current when using the improved MPPT algorithm. Thus, the track operating point is improved by using the proposed MPPT algorithm. In terms of efficiency of the standalone PV system which is calculated by dividing the load power with the maximum power of PV ar

27、ray, it is noted that the efficiency of the system is better with the proposed MPPT algorithm as compared to using the classical P&O algorithm as shown in Figure 7.5. ConclusionThis paper has presented an efficient standalone PV controller by incorporating an improved boost converter design and a ne

28、w controller scheme which incorporates both a simple MPPT algorithm and a battery charging algorithm. The simulation results show that the PV controller using the simple MPPT algorithm has provided more power and better efficiency (91%) than the classical P&O algorithm. In addition, the proposed boo

29、st converter design gives a better converter efficiency of about 93%. Such a PV controller design can provide efficient and stable power supply for remote mobile applications.中文译文：光伏发电系统的新型控制方案摘要：本文提出了一种用于光伏（PV）发电系统的新新型控制方案。所提出的计划可以控制光伏控制器升压转换器和一个微控制器使用，以提取光伏阵列最大功率和控制电池的充电过程。本文的目的是提出一个符合成本效益的升压转换器的设

30、计方案和改进的最大功率点跟踪的光伏系统算法。提出了基于MATLAB的独立光伏发电系统仿真模型并给出评价，以确保在最大功率点操作该系统的可行性。 1.引言最近，由于环境、全球变暖、能源安全、技术改进和降低成本有关的问题，PV发电系统的安装正在快速增长。光伏发电系统被认为是一种清洁环保的能源。光伏系统的主要应用是独立或并网配置。独立的光伏发电系统作为偏远地区不可或缺的电源是有吸引力的。然而，PV发电系统具有两个主要问题，其涉及约9至12的低转换效率，特别是在低照射条件下，并且由PV阵列产生的电功率的量随天气条件连续变化。因此，进行了许多研究工作以增加从PV阵列产生的能量的效率。太阳能电池V-I特性

31、是非线性的，随着辐射和温度而变化。但是在V-I和P-V曲线上有一个独特的点，称为最大功率点（MPP），在该点PV系统被称为以最大效率运行并产生其最大功率输出。MPP的位置是未知的，但可以通过计算模型或搜索算法来跟踪。因此，需要最大功率点跟踪（MPPT）技术来将PV阵列的工作点维持在其MPP。在文献中已经提出了许多MPPT技术，其中技术在许多方面各有不同，包括简单性、收敛速度、硬件实现和有效范围。然而，最广泛使用的MPPT技术是扰动和观察（PO）方法。本文提出了一个简单的MPPT算法，可以轻松实现和采用低成本光伏应用。本文的目的是设计一种改进的MPPT方法的新型PV控制器方案。提出的独立光伏控制

32、器考虑到实现数学模型每个组件以及实际的组件规范。DC-DC或升压转换器是连接在PV阵列和负载之间的前端组件。传统的升压转换器可能导致严重的反向恢复问题，并增加所有器件的额定值。因此，在这种情况下，转换效率降低，并且电磁干扰问题变得严重。为了提高转换效率，若干研究人员对许多改进的升压转换器拓扑结构进行了研究。电压钳位技术已被纳入转换器的设计，以克服输出二极管的严重反向恢复问题。在本文中，重点也是给出升压转换器设计。独立光伏系统的另一个重要组件是充电控制器，用于避免电池由于过多充电和过多放电而可能造成的损坏。研究表明，在不使用充电控制器的情况下，电池的寿命可能会下降。所提出的用于独立光伏系统的新控

33、制器方案在两个控制步骤中控制升压转换器和充电控制器。第一步是控制升压转换器，以提取光伏组件的最大功率点。在这里，高升压型转换器被认为是对加强光伏电压起作用，从而降低了串联光伏组件的数量，并保持一个恒定的直流总线电压的目的。微控制器用于获取PV组件工作电流和电压的数据采集，也用于对MPPT算法进行编程。控制器采用脉冲宽度调制（PWM）技术以随着PV电压降低而增加所产生的脉冲的占空比，以便获得接近最大功率点的稳定的输出电压和电流。第二控制步骤是为了保护电池而控制充电控制器。通过使用PWM技术控制充电电流并在充电期间控制电池电压，可以避免高于放气电压的电压。2.光伏系统设计的提出大多数独立的光伏系统仅以一种模式操作，使得光