外文翻譯---一種光伏系統(tǒng)最大功率點的控制系統(tǒng)（英文）

1、A Maximum Power Point Control Photovoltaic System M. Salhi, and R. El-Bachtiri Abstract— A maximum power point tracking control (MPPT) is used for a photovoltaic (PV) system in order to maximize the output power irres

2、pective of the temperature and irradiation conditions and of the load electrical characteristics. In this paper, we consider a photovoltaic panel supplying a battery. For maximizing its output power, we have used a bo

3、ost DC/DC converter controlled by a PI regulator. The synthesis of this regulator parameters has been achieved by using Bode method. For having a transfer function of the system, we have used a small signal modeling.

4、 Theoretical and simulated results are presented. Experimental results are conclusive. Keywords—Photovoltaic systems, maximum power point tracking, Boost dc/dc converter, PI regulator. I. INTRODUCTION photovoltaic g

5、enerator has a nonlinear behaviour. The typical power-voltage and current-voltage characteristics of photovoltaic panel are shown in Fig. 1. The product of PV output voltage and current has a maximum val

6、ue at a point called Maximum Power Point “MPP”. For the best utilization, the photovoltaic panel must operate at its MPP. However, the PV system operating point shifts out of MPP due to solar irradiation, cell tempera

7、ture or load changes. When a maximum power point tracking “MPPT” regulator is inserted between the PV system and the load, it forces the system to operate at its MPP under all conditions, resulting in improved effici

8、ency [1]. Many MPPT regulators use a microcontroller or a personal computer for implementing sophistical algorithms [2]-[5], or even neural networks [6]. These systems ensure very high performances. However they are

9、very expensive and often need a separated, stable power supply for its operation; therefore they are only suitable for high power applications [7]. Another algorithm is based on the searching of operating point which

10、verifies . 0 = ? ? V PSince the sign of “ V P ? ? ” gives the direction of MPPT searching; it is possible to determine the maximum power operating by continuous measurement of power and voltage. In recent years, many

11、MPPT applications based on this searching algorithm have been presented [8]. In [9] and [10], an analog MPPT control-system is proposed, where a boost DC/DC converter is handed for having “ V out I ? ? ” equals zero [F

12、ig. 3], where out Iis the DC/DC converter output current. In this method, in order to reduce the complexity of the Manuscript received January 13, 2010. M. Salhi is member of ″LESSI Laboratory″ in Faculty of Scie

13、nces Dhar Mehraz (FSDM), Fez, Morocco. R. El-Bachtiri is a professor in ″High School of Technology″, Fez, Morocco. system, the battery is considered as a constant voltage E and the converter is assumed to be ideal. S

14、o, the output power b P of DC/DC converter equals the PV output power . P A similar work is proposed in [11], that the battery is considered as a constant voltage in series with a constant resistance . b RThis work

15、is improved in [12] by taking into account the losses in the DC/DC converter, particularly, the switch losses in the MOSFET transistor. In this paper, we reconsider works proposed in [9]-[12] for experimental implemen

16、tation. A block diagram of the proposed system is shown in Fig 3(a). A boost DC/DC converter is used to interface the PV output to the battery in order to track the maximum power point of the PV module. For That the M

17、PPT controller must keep “ V P ? ? ” equals zero. What is possible with action on the duty cycle ( ) 1 0 ≤ ≤ α αaccording to solar irradiation λ and temperature . T Duty cycle is the one of a signal generated by t

18、he PI regulator. For synthesizing the parameters of this regulator, we have developed a transfer function for the system using a small signal model. The PI regulator coefficients p Kand i K are obtained by frequency

19、synthesis. The synoptic scheme of the proposed method is shown in Fig. 3(b). With measurements of the PV panel voltage and current, the output power is calculated and derived with respect to voltage in order to obtain

20、 the dV dPwho is compared to zero. The resulting difference signal (error signal) is used as an input signal to the PI regulator which delivers a control signal GS Vfor the boost DC/DC. II. THEORETICAL STUDY The power

21、electronic converter is a boost converter inserted between the PV generator and the battery [Fig. 2(a)]. It is controlled by a signal with a duty cycle ) 1 0 ( ≤ ≤ α α that gives the ratio between the input and the ou

22、tput voltage when the conduction is continuous. The transistor is ON during T α and OFF during the rest of the period (i.e., T ) 1 ( α ? ). The diode state, in continuous conduction mode is complementary of the tra

23、nsistor one. The inductance is charged through the transistor, and it is discharged, output through the diode, in the battery. If the chopping frequency is enough higher than the system characteristic frequencies, we

24、 can replace the converter with an equivalent continuous model. We will consider so the mean values, over the chopping period, of the electric quantities [Fig. 2(b)]. A 18th Mediterranean Conference on Control and in

25、 block (converter + battery), equations (8-11) are used. The proposed controller circuit that forces the system to operate at its optimal operating point under variable temperature and irradiation conditions is shown

26、 in Fig. 7. Fig. 6. Block diagram for system simulation Isol Rsh VI RsIsol Rsh VI Rs0.0004 A/K short-circuit current temperature coefficient at IscKI55 W maximum power Pmax17.4 V maximum power voltage Vmpp3.15 A maxim

27、um power current Impp3.45 A short-circuit current Isc21.7 V open-circuit voltage Vo25 °C cell temperature TValue Quantity Symbol0.0004 A/K short-circuit current temperature coefficient at IscKI55 W maximum power P

28、max17.4 V maximum power voltage Vmpp3.15 A maximum power current Impp3.45 A short-circuit current Isc21.7 V open-circuit voltage Vo25 °C cell temperature TValue Quantity SymbolY(s) 0 +- PI G0(s) ε(s) ?α(s) Y(s) 0 +-