CN201001050Y - Solar power supply device of super capacitor - Google Patents

Abstract

The utility model discloses a super capacitor solar power supply device relates to solar energy power generation technical field. The method tracks the maximum power of the solar system in dynamic balance. And then an intelligent charge-discharge mechanism is added according to the method to form an intelligent coordinated solar device. The solar energy storage system comprises at least one solar panel, a super capacitor, a direct current/direct current buck-boost converter, a pulse width modulation driver, a storage battery, a logic controller and a load. The electric energy generated by the solar panel is converted into the electric energy in the form of a capacitor to carry out maximum power calculation, so that the calculation procedure can be greatly simplified. The real-time performance and the reliability of tracking calculation are improved, and the efficiency of the solar system is increased. The LED solar street lamp can be widely applied to solar LED lamps and solar lamps, in particular to solar street lamps, solar traffic sign lamps, solar engineering lamps and the like.

Description

Super capacitor solar power supply device

technical field

The utility model relates to a solar charging device for a supercapacitor, belonging to the technical field of solar (photovoltaic) power generation and supercapacitors.

Background technique

Solar energy is the most common energy source that can be miniaturized. From the perspective of use, solar energy has (1) safety, reliability, no noise, and no pollution; (2) no greenhouse gases such as CO2 are produced; (3) the required energy is available everywhere, no need to consume fuel and no mechanical rotating parts; (4) maintenance Simple, long service life; short construction period, flexible scale; (5) unattended, and no need to erect transmission lines; (6) low energy costs in remote areas; (7) easy to combine with buildings and other advantages.

However, solar energy is a non-ideal renewable energy source, and the power generated by the sunlight environment, angle and temperature is significantly different. That is to say, solar energy is a variable energy source, and the generation of energy at each time point may be different. It must be supplemented by maximum power tracking to obtain the maximum electric energy converted by the solar cell.

The voltage and current of solar panels are not linear, which is a non-ideal renewable energy source. In different atmospheric environments, there will be unique working curves due to sunlight and temperature. As shown in Figure 1, strong sunshine, medium sunshine and weak sunshine have different voltage and current curves. Then look at the power voltage diagram of the solar panel, as shown in Figure 2, each working curve has a maximum power point, which is the place where the maximum energy of the solar panel is obtained. Through various maximum power tracking technologies, track the maximum power voltage and current state at different time points depending on the environment, and quickly obtain its energy injection system.

The maximum power tracking method is to detect the output power of the solar panel in real time, and predict the maximum power output under the current sky through the power algorithm, so as to change the current impedance situation to meet the maximum power requirement. In recent years, many patents have proposed a variety of maximum power tracking methods, such as the "solar power generation system" in "JP-7-129264" of Japanese patents in 1995, and the "solar battery maximum power tracking control method" in 1996 08-04445 and 08-04446. "and the "Maximum Power Control Method of Solar Cells" published in 2001, 2001-60119, U.S. Patent No. 5268832 in 1993, No. 5869956 in 1999, and CN1512286A "Solar Power Supply Device and Its maximum power point tracking control method", 2006 Tsinghua University CN1731651A "Maximum Power Point Tracking Method for Independent Photovoltaic Power Generation System" and 2006 Chinese Academy of Sciences Institute of Electrical Engineering CN1797892A "A Solar Photovoltaic Power Generation Maximum Power Point Tracking and Control Method", Taiwan Patent No. 00337886 in 1998 "Maximum Power Tracker for Solar Cells", etc.

Although the above-mentioned known technology can be used as solar maximum power tracking control, it has the following defects and limitations:

(1) The maximum power tracking of all known technologies is to check the voltage and current of the solar system, and compare the power through product or reprocessing calculation to confirm the maximum power adjustment direction. Its inspection and calculation procedures are complicated and time-consuming. Often rapid changes in sunlight or temperature make it difficult for the system to fully respond in real time, resulting in an increase in the probability of misjudgment of the maximum power point and affecting the efficiency of the solar system in obtaining electrical energy.

(2) The illuminance or temperature of the sun may change within milliseconds, and the inspection and calculation procedures of the maximum power tracking in the known technology are likely to cause errors and reduce the correctness of the maximum power adjustment of the system.

(3) The inspection and calculation circuit in the known technology is too complex, and its accuracy is often not enough for the external harsh operating environment.

Due to the above deficiency, a simpler, more real-time and accurate solar maximum power tracking control technology must be sought.

A good solar power system evaluation is divided into three parts: the first part is the "maximum power tracking" mentioned above, the second part is "effective charging method" and the third is "intelligent discharge mechanism". The above-mentioned patented technology cannot take into account the latter two. Although considerable electric energy is obtained, it loses a huge amount of electric energy in the process of storing it in the battery and discharging it to drive the load. The second part of the utility model is to propose an intelligent coordinated solar energy system device, which solves the problem of charging and discharging efficiency at the same time with the same circuit and components of "maximum power tracking", creating a reasonable, simple, real-time and efficient solar energy system.

The structure of the conventional maximum power tracking method of "perturbation and observation" for solar energy is shown in Figure 3. The structure is simple and the measurement parameters are few, and has been widely used in solar maximum power systems. The basic structure is to change the terminal voltage of the solar panel 1 and track the output power of the calculation 2 by periodically increasing or decreasing the size of the load 5 . Observe and compare the difference between the two, and then decide to increase or decrease the size of the load 5 in the next cycle. If the output power becomes larger, the load 5 will be adjusted and changed in the same trend; otherwise, if the output power becomes smaller, the direction of load variation will be changed in the next cycle. Comparing such repeated oscillating disturbances with observations, the maximum power point of the solar cell can be approached.

Make a general survey of the prior art solar charging mode and have the following defects:

(1) The solar system charging method generally adopts constant voltage or constant current charging. Because batteries (especially lead-acid batteries) are chemical energy storage, they are transformed by chemical reactions. Constant voltage or constant current charging will waste a lot of electric energy and damage the battery. For example, in constant voltage charging, the battery will be damaged if the current is too high at the initial stage of charging, while in constant current charging, the charging current is mostly used to electrolyze water to generate gas at the end of charging.

(2) Advanced solar system charging adopts multi-stage discharge and pulse charging discharge, which requires additional components and control mechanisms, resulting in more complex solar system circuits.

While the solar discharge drives the load, there are the following common deficiencies:

(1) For loads that require a constant current, such as solar LED street lights, the brightness is often dimmed gradually due to the voltage change of the battery, and the same brightness cannot be obtained.

(2) Loads that require constant current, such as solar LED street lights, are often not designed to be in the brightest state due to battery voltage.

(3) Loads that require constant voltage, such as solar machinery, are often due to changes in battery voltage, and solar machinery requires a voltage stabilizer circuit.

(4) Often the battery still has power, but the voltage is too low to drive the load.

Contents of the invention

The purpose of this utility model is to provide a supercapacitor solar charging device to solve the problem that the inspection and calculation circuits in the prior art are too complicated and difficult to adapt to the harsh operating environment. However, it is difficult for the system to fully respond in real time, resulting in an increase in the probability of misjudgment of the maximum power point, affecting the efficiency of the solar system to obtain electric energy, charging damage to the battery, and unstable discharge voltage.

In order to achieve the above purpose, it can be achieved through the following methods:

A solar panel: an array of solar units

Momentary power supercapacitor: it is a temporary storage of electric energy. In a steady state in a dynamic balance mode, the output power of the solar panel is received and the output power is sent to the DC/DC converter,

A DC/DC (DC/DC) converter: It can adjust the resistance of the load to change the output voltage of the solar panel.

A logic controller (microprocessor): Generates pulse width modulated pulses to increase or decrease the duty cycle D value of the direct current/direct current (DC/DC) converter.

1. Load: LED lights, various lights or mechanical loads.

The purpose of this utility model can also be achieved in the following ways:

1. Solar panels: arrays of solar units;

Momentary power supercapacitor: as a temporary storage, storage and second storage of electrical energy;

A DC/DC (DC/DC) buck-boost converter: adjust the load resistance, adjust the charging pulse;

A storage battery: a first accumulator;

A supercapacitor voltage detector and a first electronic switch: a voltage detector and a switch;

A logic control circuit: control solar panels, batteries, direct current/direct current (DC/DC) buck-boost converters and loads;

A second electronic switch: an electronic switch;

1. Voltage and current protection circuit: circuit protection;

A current detector: load current detection;

a load;

Its advantage of comprehensive above-mentioned utility model is:

1. The maximum power tracking method of the utility model has the characteristics of simplicity, real-time and high efficiency, so that the energy obtained by the solar energy system is much higher than that of the traditional maximum power tracking method.

2. The maximum power tracking method of this utility model only needs to detect the voltage value without the need for current and calculation procedures, which greatly improves the tracking response speed of the solar system.

3. The charging of the solar system of the utility model adopts three-stage charging, which not only prolongs the service life of the storage battery but also minimizes the loss of charging energy.

4. The discharge of the solar system of the utility model is an intelligent adjustable mode, which greatly improves the availability of the solar system load, improves the quality of the solar system and prevents the over-discharge of the battery from affecting its life.

5. The system components are reusable in each stage of operation, and the circuit is simple and multifunctional.

Description of drawings

Figure 1 is the voltage and current diagram of the solar panel under different sunlight intensities;

Figure 2 is a diagram of the output power and voltage of solar panels under different sunlight intensities;

Fig. 3 is the structural schematic diagram of the maximum power tracking device for solar energy traditional disturbance observation;

Fig. 4 is a block diagram of the basic structure of the solar maximum power tracking device of the present invention;

Fig. 5 is a structural block diagram of an intelligent embodiment of the device of the present invention.

Detailed ways

As shown in Figure 4, an embodiment of the present utility model comprises:

(1) Solar panel 6: It is an array of solar cells, which are connected in series and parallel according to the required output voltage and current, and convert photoelectricity into electrical energy under various sunlight intensities.

(2) Instantaneous power type supercapacitor 7: refers to a capacitor with low internal resistance and high capacitance, which can be used as a temporary storage of electric energy. In the steady state in a dynamic balance mode, the output power of the solar panel is received and the output power is sent to the DC/DC converter. The instantaneous power type supercapacitor may be a supercapacitor of metal oxide electrodes, a carbon material supercapacitor, a polymer supercapacitor, a hybrid type ultracapacitors, aluminum electrolytic capacitors or similar high capacitance capacitors.

(3) Logic controller (microprocessor) 9: Generate pulse width modulation pulses to increase or decrease the duty cycle D value of the direct current/direct current (DC/DC) converter.

(4) Direct current/direct current (DC/DC) converter 8: It is a boost converter, which can adjust the resistance of the load to change the output voltage of the solar panel. The DC/DC converter may also be a buck converter, a buck-boost converter or other similar DC/DC converters.

Put the supercapacitor 7 between the solar panel 6 and the DC/DC converter 8, as shown in Figure 4, as a temporary storage container for energy (electric energy), the electrical energy is generated by the solar panel 6, enters the supercapacitor 7, and then outputs DC/DC The converter 8 is adjusted by the logic controller 9 and finally enters the storage battery 10 . In the steady state, the incoming and outgoing electric energy can be seen as zero net electric energy of the supercapacitor, that is, no electric energy is stored in the supercapacitor, and the energy generated by the solar panel flows into the DC/DC converter, presenting a dynamic balance state.

Solar system energy (electric energy) W=P×t

P: power, t: time

∴W=I×V×t

remove the time factor;

Discuss in 1 second, t=1sec

Then W=P=I×V

At any moment, the energy flowing into the supercapacitor = the energy flowing out of the supercapacitor, that is, the energy flowing into the supercapacitor from the solar panel should be the energy flowing into the DC/DC converter from the supercapacitor.

The energy generated by the solar panel = the energy flowing into the ultracapacitor = the energy flowing out of the ultracapacitor = the energy flowing into the DC/DC converter

Therefore, the previous solar maximum power tracking method needs to detect the power generated by the solar panel, and now it can also detect the energy or power of the supercapacitor.

The energy of a supercapacitor is related to its capacitance:

W=1/2C×V ²

W: the energy of the supercapacitor, C: the capacitance of the supercapacitor, V is the voltage of the supercapacitor

The capacitance C value of the supercapacitor is a fixed value, so the energy of the supercapacitor can be presented by the voltage of the supercapacitor. As long as there is a voltage of the supercapacitor, the energy of the supercapacitor can be known, and the power generated by the solar panel can also be known. Therefore, this method only detects the voltage of the supercapacitor, which is simple and efficient. Its operation flowchart is shown in Fig. 5 .

When the duty cycle D value changes and the voltage of the supercapacitor increases, that is, the energy generated by the solar panel is more than the energy flowing into the converter, the duty cycle D value will change in the original direction, otherwise, it will change in the opposite direction. Comparing such repeated oscillating disturbances with observations, the maximum power point of the solar cell can be approached.

Referring to Fig. 5, the intelligent embodiment of the present utility model comprises:

A supercapacitor voltage detector Vc and a first electronic switch SW1 connected between the solar panel 6 and the DC/DC converter 8;

A second electronic switch SW2 connected between the DC/DC converter 8 and the load 10;

a storage battery 3 connected between said second electronic switch SW2 and ground;

A voltage and current protection circuit 5 connected between the input terminal of the load 10 and the logic controller 9;

A current detector 4 connected between the load 10 and the logic controller 9 .

The workflow of the device is:

(1) Adopt the above-mentioned "Peter Energy Disturbance Observation Solar Maximum Power Tracking Method";

(2) Three-stage charging method is adopted:

The logic control circuit 9 determines the charging mode of the battery 3 according to the voltage status of the battery 3 (feedback from the voltage and current protection circuit 5 to an input terminal of the logic control circuit 9 ). The current and voltage are adjusted by the DC/DC converter 8 to charge the storage battery 3 . This system charges in the pulse charging mode when the voltage of the battery 3 is low, and when it is charged above the set voltage, the energy generated by the solar panel 6 at the moment is fully charged to the battery 3, and then it is charged in the pulse charging mode at the later stage of charging. Full battery 3. This three-stage charging method has the characteristics of high efficiency, fast and low energy consumption.

(3) Intelligent adjustable discharge mode:

The discharge of the solar energy system is adjustable, the discharge mode is determined by the logic control circuit 9 , and the constant voltage or constant current or other discharges are controlled by the current/direct current converter 8 . The DC/DC converter 8 can convert the output of the solar power supply device. The system load 10 can be an array of LED lights, Lamp, mechanical device, monitoring equipment, detection instrument and signal communicator, etc.

If the load 10 is an array of LED lamps, a constant current is required to control the brightness, and the storage battery of the solar system is mostly a 12V lead-acid battery for energy storage and discharge. It can reach 16V when fully charged, and the use range is mostly between 13.8 and 11V. When the LED is driven by the battery, the LED drive current will fluctuate due to the voltage change of the lead-acid battery, so the brightness of the LED light will gradually dim. Intelligent adjustable constant current control can keep the brightness of LED street lights constant. The constant current control is used to make the serial current through the LED consistent, and the street lamp will not be dimmed.

Some loads require constant voltage, such as mechanical devices, monitoring equipment, detection instruments, etc. A constant voltage can make the machine work stably. Through this device, the constant voltage discharge control can be more efficient, and the output can even be increased to a higher fixed voltage for the load.

The device has a simple structure but can integrate multiple functions to obtain the best control mechanism of the solar energy system with the least parts.

The working process of the present utility model comprises the following stages:

(1) In the maximum power tracking stage, use the "Peter energy disturbance observation solar maximum power tracking method", which includes the following steps:

Step 1: Detect the voltage Vc value of the supercapacitor 7:

If the Vc value is less than or equal to the set value, the maximum power system will not be activated;

If the Vc value>set value, the logic controller 9 starts the maximum power system;

Step 2: Set the DC/DC converter 8 working cycle D1 value, and measure the new Vc value;

Step 3: Change the duty cycle D2 value of the DC/DC converter 8 by the logic controller 9, that is, change the load resistance.

Step 4: Measure the latest Vc value again,

If the latest Vc value > new Vc value, then adjust the DC/DC converter duty cycle D value, and its direction of change is towards the original change direction, that is: if the D value increases (D2>D1), then the next D3 will continue to increase (D3 >D2), D3>D2>D1; if D value decreases (D2<D1), then the next D3 will continue to decrease (D3<D2), D1>D2>D3.

If the latest Vc value < the new Vc value, then adjust the DC/DC converter duty cycle D value, and the direction of its change trend is in the opposite direction;

If the latest Vc value=new Vc value, then maintain the duty cycle D value of the DC/DC converter;

Step 5: Repeat step 4 until the Vc value ≤ the set value, and close the maximum power system.

(2) In the charging stage, a three-stage charging method is used. When the voltage of the battery 3 is low, it will be charged in the pulse charging mode. When it is charged above the set voltage, the energy generated by the solar panel 6 at the moment will be fully charged to the battery 3. After reaching the later stage of charging, the battery 3 will be fully charged in the pulse charging mode. .

(3) In the discharge stage, an intelligent adjustable mode is adopted, the discharge mode is determined by the logic controller 9 , and the constant voltage or constant current or other discharge is controlled by the current/direct current converter 8 . The DC/DC converter 8 can change the output of the storage battery through the electronic switch 2 .

Ultracapacitors play the role of replacing batteries in many electronic power applications, such as RTC backup memory and solar LED lights. In the past, the energy density of supercapacitors was much lower than that of batteries, which limited their application in energy storage. In recent years, the energy density of supercapacitors has increased rapidly, and alternative batteries can be seen everywhere. The direct current storage of the solar energy system is gradually considered to put supercapacitors, especially in the maximum power point tracking. U.S. Patent No. 2006/0312102 also proposes a high-efficiency solar system to charge the supercapacitor with maximum power. A circuit can be designed for maximum power tracking and constant power charging for supercapacitors.

Ultracapacitors can be roughly divided into two types: energy release type and instantaneous power type. The characteristics of the former tend to be batteries, which mainly store energy. Because it is physical energy storage, its service life and reliability are far higher than those of chemical reaction batteries. The latter is mainly able to provide powerful power in an instant, and its characteristics are similar to capacitors, with the power characteristics of an instant burst. The utility model uses an instantaneous power supercapacitor connected in series between a solar panel and a direct current/direct current (DC/DC) converter, and utilizes its low internal resistance and fast response characteristics as an energy storage device in a steady state. . Construct a novel, real-time and efficient solar maximum power tracking method. In addition, an intelligent coordinated solar installation system is designed using this maximum power tracking method.

Claims (6)

1. a ultracapacitor solar energy power source apparatus is characterized in that: comprise

One solar panels are luminous energy and electric energy transition components, and connection in series-parallel on demand forms;

The power type super capacitor is the accumulator of dynamic equilibrium in a flash, stores solar panels output energy and exports electric energy to DC-DC converter;

One DC-DC converter can be adjusted the output voltage and the energy of solar panels and ultracapacitor; Output at DC-DC converter is connected to load or storage battery;

One logic controller according to the variation of the output voltage of solar panels and ultracapacitor, increases or reduces the work period D value of DC-DC converter.

2. ultracapacitor solar energy power source apparatus according to claim 1, it is characterized in that: described instantaneous power type ultracapacitor is the large value capacitor of low internal resistance or high power, and this capacitor is the aluminium electrolytic capacitor of super capacitor, metal oxide electric capacity, gold capacitor and the high capacitance of various high-energy-densities and high power density.

3. ultracapacitor solar energy power source apparatus according to claim 1 is characterized in that: also comprise

One is connected the electrochemical capacitance detecting voltage device and first electronic switch between described solar panel and the DC-DC converter;

One is connected second electronic switch between described DC-DC converter and the load;

One is connected the storage battery between described second electronic switch and the ground connection;

One is connected the input of described load and the electric current and voltage protective circuit between the described logic controller;

One is connected the current sense device between described load and the described logic controller.

4. ultracapacitor solar energy power source apparatus according to claim 1 is characterized in that: described storage battery comprises rechargeable batteries such as NI-G, ni-mh, lithium ion, lithium macromolecule, lead-acid battery.

5. ultracapacitor solar energy power source apparatus according to claim 1 is characterized in that: described instantaneous power type ultracapacitor can be used as second accumulator when energy storage.

6. ultracapacitor solar energy power source apparatus according to claim 1 is characterized in that: described instantaneous power type ultracapacitor is when discharge, but the multiple-connected battery discharge, with enhanced discharge power.

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