Optical fiber temperature measuring device for photovoltaic cell assembly

Abstract

The present invention relates to the technical field of photovoltaic temperature measurement, and in particular to an optical fiber temperature measuring device for a photovoltaic cell assembly, comprising a photoelectric conversion module, a fluorescent temperature measuring probe, a bare optical fiber, a conducting optical fiber, an ST-FC adapter, a heat shrink tube and a groove provided on the photovoltaic cell assembly, wherein the groove extends to the edge of a photovoltaic panel assembly, the end of the bare optical fiber is provided with a fluorescent temperature measuring probe, the bare optical fiber with the fluorescent temperature measuring probe is led out along the groove on the surface of the photovoltaic cell assembly to the edge of the photovoltaic cell assembly, the fluorescent temperature measuring probe is tightly fixed in the groove on the surface of the photovoltaic cell assembly, the bare optical fiber is connected to the photoelectric conversion module through the conducting optical fiber and the ST-FC adapter, and a heat shrink tube is sleeved at the junction of the conducting optical fiber and the edge of the groove of the photovoltaic cell assembly; the optical fiber temperature measuring device provided by the present invention places the probe directly on the surface of the photovoltaic cell, directly contacts with the hot spot of the crystal, can follow the temperature rise of the crystal surface more quickly, and reflect the real-time temperature.

Description

Technical Field

[0001] The invention relates to the technical field of photovoltaic temperature measurement, in particular to an optical fiber temperature measurement device for a photovoltaic cell assembly. Background Art

[0002] Photovoltaic power generation relies on the photoelectric effect to generate electricity, directly converting solar radiation energy into electrical energy. Photovoltaic power generation is a non-concentrating application, and the energy distribution density of the irradiation is usually small, requiring the use of more components and occupying a larger area.

[0003] The photoelectric efficiency of photovoltaics is generally 10%-15%, which means that at least 85% of the light energy will be converted into heat energy. Light intensity and photovoltaic cell junction temperature are the most important parameters affecting output power, and light intensity affects the change of junction temperature. The increase of light intensity will increase the output short-circuit current and maximum power point current. The increase of junction temperature will linearly reduce the open circuit voltage and maximum power point voltage. When the junction temperature rises, the total output power of the solar cell will decrease. Photovoltaic crystals are particularly afraid of temperature rise. The temperature rise will reduce the photoelectric conversion efficiency and even burn the photovoltaic cell components. Therefore, heat dissipation has become the key to the success or failure of solar photovoltaic power generation applications.

[0004] At present, the temperature of the surface of photovoltaic cells is measured by the water temperature of the water system in the assembly, that is, the temperature of the crystal on the surface of the photovoltaic cell needs to be transferred to the water through the backplane, and then a temperature sensor is placed at the water outlet. Since the temperature is not measured directly, the temperature lag is serious. Therefore, when the temperature of the photovoltaic cell is too high, the corresponding heat dissipation and cooling system cannot work in time to dissipate heat, which can easily cause overheating and damage of the photovoltaic crystal components. Summary of the invention

[0005] In order to solve the above problems, the present invention provides an optical fiber temperature measuring device for a photovoltaic cell assembly.

[0006] The present invention is achieved through the following technical solutions:

[0007] A fiber optic temperature measuring device for a photovoltaic cell assembly comprises a photoelectric conversion module, a fluorescent temperature measuring probe, a bare optical fiber, a conductive optical fiber, an ST-FC adapter, a heat shrink tube and a groove formed on the photovoltaic cell assembly, wherein the groove extends to the edge of the photovoltaic panel assembly, the end of the bare optical fiber is provided with a fluorescent temperature measuring probe, the bare optical fiber with the fluorescent temperature measuring probe is led out along the groove on the surface of the photovoltaic cell assembly to the edge of the photovoltaic cell assembly, the fluorescent temperature measuring probe is tightly fixed in the groove on the surface of the photovoltaic cell assembly, the bare optical fiber is connected to the photoelectric conversion module through the conductive optical fiber and the ST-FC adapter, a heat shrink tube is sleeved at the junction of the conductive optical fiber and the edge of the groove of the photovoltaic cell assembly, the photovoltaic cell assembly is mounted on a back plate, the water cooling and heat dissipation system is connected to an external water supply system through a solenoid valve, the photoelectric conversion module is connected to the solenoid valve through a temperature control unit, and the temperature control unit adjusts the opening of the solenoid valve according to a temperature signal output by the photoelectric conversion module.

[0008] Preferably, the length of the bare optical fiber matches the length of the groove.

[0009] Furthermore, the fluorescent temperature measuring probe is fixed in the groove by gluing with high temperature resistant glue.

[0010] Furthermore, the heat shrinkable sleeve is glued and fixed by high temperature resistant glue.

[0011] Furthermore, the temperature control unit includes a limiter, a differential regulator, an adder, a proportional regulator, an integral regulator, a drive amplifier, a temperature setting unit and a proportional amplifier. The limiter, differential regulator, adder, proportional regulator, integral regulator and drive amplifier are connected in sequence, the temperature setting unit is connected to the proportional regulator, the limiter is connected to the photoelectric conversion module, the drive amplifier is connected to the solenoid valve, and the proportional amplifier is connected between the photoelectric conversion module and the proportional regulator.

[0012] Furthermore, the control method of the temperature control unit is to divide the temperature feedback signal into two signal parts for processing;

[0013] A part of the signal is set through the limiter's limit ratio to adjust the feedforward control strength, and then processed by the differential regulator to extract the actual temperature change trend from the temperature feedback signal and use it as the feedforward control quantity. This control quantity is superimposed on the temperature setting value set by the temperature setting unit and then processed by the proportional regulator and the integral regulator;

[0014] The other part of the temperature feedback signal is amplified by the proportional amplifier as negative feedback and then processed by the proportional regulator and the integral regulator;

[0015] The control signal output by the integral regulator is amplified by the drive amplifier to adjust the opening of the solenoid valve.

[0016] Preferably, the temperature control unit also includes a wireless communication module.

[0017] The beneficial effects of the present invention are:

[0018] 1. The optical fiber temperature measurement device provided by the present invention places the probe directly on the surface of the photovoltaic cell, directly in contact with the hot spot of the crystal, and can follow the temperature rise of the crystal surface more quickly to reflect the real-time temperature.

[0019] 2. Structurally, temperature information can be transmitted using only one optical fiber. The bare optical fiber is only micrometer-level thick. The optical fiber with the probe is embedded in the groove at the joint of the surface of the photovoltaic panel, which will not affect the lighting performance of the photovoltaic cell assembly.

[0020] 3. The optical fiber temperature measurement probe is not charged, is not afraid of on-site electromagnetic interference, and will not cause any interference. It has better stability.

[0021] 4. The probe directly contacts the hot spot of the crystal, which has strong real-time performance and higher temperature measurement performance.

[0022] 5. This device measures temperature through optical fiber and has the advantages of corrosion resistance, long life, safe and reliable use, and maintenance-free.

[0023] 6. The temperature control unit detects and controls the temperature of the photovoltaic cell module surface in real time by controlling the cooling water volume in accordance with the feedforward control system control mode, which can achieve a zero-difference control effect and ensure the rapidity of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0025] Attached Figure 1 is a schematic diagram of the present invention;

[0026] Attached Figure 2 It is a schematic diagram of the installation of the transmission optical fiber;

[0027] Attached Figure 3 It is a connection diagram of the photoelectric conversion module;

[0028] Attached Figure 4 It is a schematic diagram of the grooves on the surface of the photovoltaic cell module;

[0029] Attached Figure 5 It is a schematic diagram of wireless communication of the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0032] Reference Figure 1-4, an optical fiber temperature measuring device for a photovoltaic cell assembly, comprising a photoelectric conversion module 6, a fluorescent temperature measuring probe 4, a bare optical fiber 3 (wherein the diameter of the bare optical fiber 3 is 200 μm), a transmission optical fiber 1 (wherein the transmission optical fiber 1 is an optical fiber protected by a Teflon sleeve), an ST-FC adapter 5, a heat shrink tube 2, and a groove 8 opened on a photovoltaic cell assembly 9, wherein the groove 8 is about 2 mm wide and about 1 mm deep; the groove 8 extends to the edge of the photovoltaic panel assembly 9, and the length of the groove 8 is greater than 30 mm; the end of the bare optical fiber 3 is provided with a fluorescent temperature measuring probe 4, the diameter of the temperature measuring probe is only 0.5 mm, and the length of the bare optical fiber 3 is adapted to the length of the groove 8; the bare optical fiber 3 with the rare earth fluorescent temperature measuring probe 4 is led out to the photovoltaic cell assembly along the groove 8 on the surface of the photovoltaic cell assembly 9 9 edge, the fluorescent temperature measuring probe 4 is tightly fixed in the groove 8 on the surface of the photovoltaic cell assembly 9, the bare optical fiber 3 is connected to the photoelectric conversion module 6 through the conductive optical fiber 1 and the ST-FC adapter 5, and the junction between the conductive optical fiber 1 and the edge of the groove 8 of the photovoltaic cell assembly 9 is covered with a heat shrink tube 2 for enhanced protection; the photovoltaic cell assembly 9 is installed on the back plate 7, and the water cooling system is connected to the external water supply system through the solenoid valve (in this embodiment, the water supply system is composed of a water pump and a water pool, that is, the water pump is operated to input the water in the water pool into the water cooling system), the photoelectric conversion module 6 is connected to the solenoid valve through the temperature control unit, and the temperature control unit adjusts the opening of the solenoid valve according to the temperature signal output by the photoelectric conversion module 6, thereby realizing the adjustment of the temperature of the surface of the photovoltaic cell assembly 9.

[0033] Furthermore, the fluorescent temperature measuring probe 4 is fixed in the groove 8 by gluing with high temperature resistant glue.

[0034] Furthermore, the heat shrinkable sleeve 2 is glued and fixed by high temperature resistant glue.

[0035] Furthermore, the temperature control unit includes a limiter, a differential regulator, an adder, a proportional regulator, an integral regulator, a drive amplifier, a temperature setting unit and a proportional amplifier. The limiter, the differential regulator, the adder, the proportional regulator, the integral regulator and the drive amplifier are connected in sequence. The temperature setting unit is connected to the proportional regulator, the limiter is connected to the photoelectric conversion module 6, the drive amplifier is connected to the solenoid valve, and the proportional amplifier is connected between the photoelectric conversion module 6 and the proportional regulator.

[0036] The control method of the temperature control unit is to divide the temperature feedback signal into two signals for processing;

[0037] Part of the signal is processed by the limiter ratio setting of the limiter to adjust the feedforward control strength, and then the actual temperature change trend is extracted from the temperature feedback signal through the differential regulator, and used as the feedforward control quantity. The control quantity is superimposed with the temperature setting value set by the temperature setting unit and then proportional integral control is performed (processed by the proportional regulator and the integral regulator); the actual temperature change trend can be extracted from the temperature feedback signal through the differential regulator, and superimposed with the temperature setting as the feedforward control quantity, so as to "correct" the control direction of the next temperature in advance. Improve the rapidity of the system. When the actual temperature is basically stable, the feedforward control quantity of the temperature control obtained by the differential regulator is almost zero, and the feedforward quantity does not participate in the control. Relying on proportional differential integral control, the actual temperature is basically consistent with the target set temperature.

[0038] The other part of the temperature feedback signal, as negative feedback, is directly involved in the proportional-integral operation after being amplified by the proportional amplifier (that is, it is then processed by the proportional-proportional regulator and the integral regulator); relying on the control action of the proportional-integral regulator, a zero-difference control effect is achieved.

[0039] The control signal output by the integral regulator is amplified by the drive amplifier to adjust the opening of the solenoid valve.

[0040] Furthermore, the temperature control unit also includes a wireless communication module; Figure 5 The wireless communication module is connected to the 4G or 5G cloud platform through wireless communication methods such as NB-IoT, and is connected to remote PC clients, mobile terminals, large-screen monitoring and other devices to achieve remote display and control.

[0041] As a further improvement, the temperature control unit is integrated with an early warning unit. When the measured temperature reaches a preset temperature alarm value, the temperature control unit sends out control signals such as sound and light emergency alarm signals.

[0042] When working, the photoelectric conversion module 6 generates excitation light, which is excited to the temperature probe 3 with rare earth material through the transmission optical fiber 1. After the excitation light disappears, the temperature probe 3 generates fluorescence. The decay life of the fluorescence generated on the temperature probe 3 carries temperature information. The fluorescence returns from the transmission optical fiber 1 to the photoelectric conversion module 6. After photoelectric conversion, processing and analysis, the real-time temperature of the hot spot where the temperature probe is installed is obtained and sent back to the temperature control unit as a feedback signal of the control system. Since the cooling water temperature control is a large inertia system, in order to improve the rapidity of the system, the temperature control unit adopts a feedforward control method. After the output signal of the temperature control unit is amplified by the drive, the opening of the cooling water solenoid valve is controlled to control the water intake of the cooling water. The back plate 7 is cooled by the water cooling heat dissipation system, and then the photovoltaic cell assembly 9 is cooled. The surface temperature of the photovoltaic cell assembly 9 is kept at around the set temperature.

[0043] When the measured temperature reaches a preset temperature alarm value, the temperature control unit sends out control signals such as sound and light emergency alarm signals.

[0044] Since concentrated photovoltaic cells (CPV) are distributed outdoors in large numbers, a wireless communication module is designed inside the temperature control unit corresponding to each set of photovoltaic cell components. The wireless communication module is connected to the 4G or 5G cloud platform through wireless communication methods such as NB-IoT, as shown in the figure. The 4G or 5G cloud platform is connected to the background PC client, mobile terminal, large-screen monitoring and other devices to achieve remote display and control.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An optical fiber temperature measuring device for a photovoltaic cell assembly, characterized in that: The invention comprises a photoelectric conversion module (6), a fluorescent temperature measuring probe (4), a bare optical fiber (3), a transmission optical fiber (1), an ST-FC adapter (5), a heat shrink tube (2), and a groove (8) provided on a photovoltaic cell assembly (9), wherein the groove (8) extends to the edge of the photovoltaic cell assembly (9), the end of the bare optical fiber (3) is provided with a fluorescent temperature measuring probe (4), the bare optical fiber (3) provided with the fluorescent temperature measuring probe (4) is led out along the groove (8) on the surface of the photovoltaic cell assembly (9) to the edge of the photovoltaic cell assembly (9), and the fluorescent temperature measuring probe (4) is closely fixed to the photovoltaic cell assembly (9). ) on the surface of the photovoltaic cell assembly (9), the bare optical fiber (3) is connected to the photoelectric conversion module (6) through the transmission optical fiber (1) and the ST-FC adapter (5), the edge of the groove (8) of the transmission optical fiber (1) and the photovoltaic cell assembly (9) is covered with a heat shrink tube (2), the photovoltaic cell assembly (9) is installed on the back plate (7), the water cooling system is connected to the external water supply system through the electromagnetic valve, the photoelectric conversion module (6) is connected to the electromagnetic valve through the temperature control unit, and the temperature control unit adjusts the opening of the electromagnetic valve according to the temperature signal output by the photoelectric conversion module (6); The temperature control unit comprises a limiter, a differential regulator, an adder, a proportional regulator, an integral regulator, a drive amplifier, a temperature setting unit and a proportional amplifier, wherein the limiter, the differential regulator, the adder, the proportional regulator, the integral regulator and the drive amplifier are connected in sequence, the temperature setting unit is connected to the proportional regulator, the limiter is connected to the photoelectric conversion module (6), the drive amplifier is connected to the electromagnetic valve, and the proportional amplifier is connected between the photoelectric conversion module (6) and the proportional regulator; The control method of the temperature control unit is to divide the temperature feedback signal into two parts of signals for processing; A part of the signal is set through the limiter's limit ratio to adjust the feedforward control strength, and then processed by the differential regulator to extract the actual temperature change trend from the temperature feedback signal and use it as the feedforward control quantity. This control quantity is superimposed on the temperature setting value set by the temperature setting unit and then processed by the proportional regulator and the integral regulator; The other part of the temperature feedback signal is amplified by the proportional amplifier as negative feedback and then processed by the proportional regulator and the integral regulator; The control signal output by the integral regulator is amplified by the drive amplifier to adjust the opening of the solenoid valve.

2. The optical fiber temperature measuring device for photovoltaic cell assembly according to claim 1, characterized in that: The length of the bare optical fiber (3) is matched to the length of the groove (8).

3. The optical fiber temperature measuring device for photovoltaic cell assembly according to claim 1, characterized in that: The fluorescent temperature measuring probe (4) is fixed in the groove (8) by gluing with high temperature resistant glue.

4. The optical fiber temperature measuring device for photovoltaic cell assembly according to claim 1, characterized in that: The heat shrink tube (2) is glued and fixed by high temperature resistant glue.

5. The optical fiber temperature measuring device for photovoltaic cell assembly according to claim 1, characterized in that: The temperature control unit also includes a wireless communication module.

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