digital batteries

Production of renewable solar energy can be divided into solar energy (also called photovoltaic) and solar thermal energy categories, the latter more complex the technology, only for relatively large capacity, limited the application, then the practical application of this less. Solar electricity is inexhaustible, nonpolluting and many other benefits, has become a hot pursuit of the man for a new energy. But it is also applied intermittently, electricity and climate-related defects. Therefore, to improve the efficiency of solar cells, monitoring of electricity generation in real time is necessary, you can work in the early detection of solar cells appear abnormal. Presents a real-time monitoring of the design of solar cells power production system. System using AT89S52 MCU, using current sensor on the output of solar cells being measured, the advantage is that it almost does not consume energy case, the current is converted to a voltage for measurement. Dell Latitude D810 battery Dell Latitude D820 battery

A hardware design system

Hardware circuit of Figure 1, primarily by the group of solar cells, consisting of Hall effect current sensors, I / U conversion circuit, liquid crystal display comprising 1602 AT89S52 system chip microprocessor control, and composition of rechargeable lead-acid battery energy system of 5 parts. Course work: when the solar cell receiving light to produce current, battery charging, MCU through the control device under the battery voltage, the electricity generated from solar cells on signal acquisition in real time. As the MCU can receive voltage signals before receiving the signal of I / U, U / conversion module signal U will be transferred to the proper voltage. The internal operation, resulting in the delivery device 1602 the capacity of the battery LCD display.

1.1   A D converter module

When the analog input signal is required after SCM converted into digital signals, the need to simultaneously measure voltage and current output of solar cells, it is ADC0832 8-bit dual-channel serial A / D converter, A / D conversion accuracy depends on the degree of high stability voltage reference base, the reference voltage is 5 V, generated by the TL431. RC filter after the analog signal input in the ad, then after the serial output ADC. Dell Latitude D830 battery Dell Studio 14 battery

1.2 I / U Converter Module

MCU interfaces for I / O can only receive 0 ~ 5 V voltage signals in real time capture of solar cell output current required to convert the signal current signal voltage, the system is the photovoltaic system, the ancillary equipment, energy consumption is as low as possible priority. Hall current sensor thus becomes the first choice, according to Hall-effect theory to work, almost no energy in the case of the current signal into voltage signal. The system uses TBCl0SY Hall type current sensor, the nominal output voltage (± 4% ± 0.5) V, ± 15 V dual supply, current measurement range of O ~ 15 A, may in principle respond to small PV off-grid application.

1.3 Food

MCU running on the need for on-chip FETs or supply of energy to work in the corresponding state. AT89S52 requires a 5 V power supply (the actual working voltage is 3.6 ~ 6.0 V). Rectifier available regulating power mode, the voltage was 4.5 V or so, because the system is independent power production, and use long term, taking account of the life of the power unit to provide municipal power or battery is not realistic, so that most good program should be in system batteries of solar cells, regulated by the regulator block 7805 and to 5 V, Vcc input pin MCU, MCU and LCD driver devices. TBCl0SY Hall sensors ongoing need to ± 15 V dual supply, as well, the supply battery power within the system. The collector controller 7805.7915 ± 15 V regulator, and thus drive their work. Dell Studio 1435 battery Dell Studio 1436 battery

1.4 Module Output Display

The fee is calculated as Q = ITU, which needs time T can make their own determination in the programming software, such as every 3 min sampling time, the internal operations in 1602, the discharge capacity LCD. To save energy, by setting the relays, so that the LCD automatically after 10 seconds off.

2 System Software

System Software primarily completed by the MCU, the main data acquisition and display control, the software design the entire system is modular thinking, measurement and display its program flow illustrated in Figure 2. Dell Vostro 1000 battery Dell Vostro 1014 battery

3 System Test and Analysis

200 W systems of small off-grid photovoltaics, for example, the nominal voltage of 24V, maximum current of 6.18 A, 200 Ah battery. Design of the normal discharge time for the 2 ~ 3 d, 0 ~ 6.18 A percentage of current is converted to 0 ~ 5 V voltage, resistance posed by the two attenuator, the ratio of output voltage amplification of resistors R1 and R2, the ratio of the decision set U / U conversion rate of 5 / 24, while R7 = 10 kW + R6 = 48 kΩ Rp2. According to the formula Q = charge time ITU test, is 12:00 to 2:00 p.m., the electricity of the show started, every 3 min showed real power and control system in the data, the second error of less than 3%, the table 10 are in the position of the initial measurement error, with the power increases, the margin for error is gradually reduced. Dell Studio 1735 battery Dell Studio 1737 battery

4 Conclusion

The microcontroller AT89S52, Hall effect sensors in the liquid crystal and during 1602 the production of solar, the monitoring system in real time is simple, inexpensive and maintenance free, energy efficient and small-time monitoring actual production of solar cells, the early detection of abnormalities occurring in solar cells work. The system is designed as photovoltaic system accessories for small off-grid photovoltaic systems and system components, the life, durable and reliable, so in the off-grid PV system has many applications. Dell Studio 1537 battery Dell Studio 1555 battery

3-grid system power has the advantage

And off-grid power systems solar system generation grid has the following advantages:

1. The use of clean energy and renewable solar energy naturally, do not consume non-renewable and limited resources, the carbon content of fossil fuels, the use of greenhouse gas emissions and emissions of pollutants, and harmony of the ecological environment, and in accordance with the economic and social development strategy. PC764 Y9943 Latitude D620 battery

2. Electricity can be injected into the network as a network storage device. When the load power is high, solar electric energy shortage on the purchase of electricity to the city. Although the burden is small or does not use electricity, you can sell electricity to the electricity surplus. At the rear, according to the principle of the grid system and the elimination of the battery, thereby broadening the scope of use and flexibility, improve the MTBF of the system and the battery of secondary pollution, and reduce costs.

3. Components of photovoltaic cells and the construction of the perfect combination of these two sectors, but also as building materials and decorative materials to make full use of material resources to play a variety of functions, not only reduce construction costs and also allow the building to improve the scientific content and technology to increase the “points of sale.” PA3399U-2BRS PA3465U-1BRS

4. Distributed construction of distributed power generation and supply the nearest place to get in and out of network flexibility, not only strengthen the power of resisting war and disasters, and helps to improve the system of ‘load balancing power and reduces line losses.

4, the impact on solar power system

As part of the density of solar photovoltaic and low, stable poor, poor regulatory capacity of power generation by the weather and geographical impact of the power grid will provide greater security, stability economic cooperation, and quality of power supply due to a certain extent.

1. For the impact of the trend line

Without access to grid-connected photovoltaic systems, where the distribution trend line is usually a one-way flow and that the distance between the post and increase monotonically to reduce active power. However, when the dispersed network access energy distribution after the system fundamentally changed the pattern of the trend and the trend has become unpredictable. VGP-BPS8 VGP-BPS8A VGP-BPL8 PV system power generation and the network later, when the right system for photovoltaic electricity to power the output power, under the system of photovoltaic power generation and load of the spatial relationship along the trend line may be added may also be reduced. When the line of photovoltaic system output is greater than the load current, the line portions of all or part of the trend may be reversed. The trend of this unconventional mode will produce a wide range of effects such as changes in the trend, it is difficult to maintain voltage regulation; also lead to equipment distribution network voltage control ( such as voltage regulators to not load tap transformers, switches capacitor group) abnormal response, and the flow of the sub-station photovoltaic power generation system when the tide is large enough, the system photovoltaic power generation in the vicinity of the device may be more overload or voltage limit, thereby affecting the reliability of the system. Meanwhile, the new generation of photovoltaic power systems, because of their great influence on the output by the weather, with random changes, which makes the system, the random nature of the trend.

2. For system protection

When the grid then there are several scattered power after the short circuit will increase, leading to more protection against surges to failure and excessive load short-circuit will also affect labor fuses. In addition, no prior access to the system of photovoltaic power generation is generally radial distribution network, its protection has no meaning, while access to the system of photovoltaic power generation, all distribution network includes more power in a network of tidal flow uncertainty, therefore, should require the installation of a directional protection, but fuses traditional and automatic re-closing devices has no direction. The protection system is based on traditional design of the radial grid-based, distributed generation in distribution network in the deep demand for basic protection system design should also be amended accordingly. VGP-BPS2 VGP-BPS2A VGP-BPS2C

3. Do not reduce the amount of the traditional owners of rotating machinery

As the grid-connected PV system has the capacity to peak load and frequency modulation, which will power the load early evening peak and the impact of peak load. Because grid-connected PV system to increase the capacity of energy production does not reduce the generating units of power system has a volume or redundant, it must be a photovoltaic power generation to prepare reserve units corresponding spinning for peak morning peak and evening peak problems. Grid-connected PV systems to the grid is a unit decrease in the use of the cost of a few hours. It is of course the power suppliers do not want to see.

Occur due to the cyclical nature of sun and loads, photovoltaics connected to the network to increase capacity and does not reduce the demand on the power installed capacity. When a city grid photovoltaic roof and reached a certain size, if a radical change in the geographical weather, power grids will be connected to the PV system to provide spinning reserve units of regional capacity and adequate compensation of reactive power to control and adjust the system frequency and voltage. In this case, the grid will be sacrificed at the expense of economic cooperation to ensure security and stability of operation of the supply network. VGP-BPL8A VGP-BPS9 VGP-BPS9A/B

4. For the impact of power quality

Access network will spread fluctuation of voltage supply and flicker, and harmonics. Large photovoltaic power generation system startup, or system output of photovoltaic power generation or a sudden change took place will cause a greater change in voltage fluctuations and flicker. As the system of photovoltaic power generation as a source of energy distributed itself is a source of harmonics and a portion of the grid signal broadcast by the access inverter, so inevitable that produces harmonics.

5. Energy saving effects of emission reduction should be explored in depth

Grid one of the main advantages of the use of other fossil fuels. As grid-connected solar power plants for electricity generation increased by turning the generator spinning reserve or backup system, therefore, grid-connected PV real savings rate should be lower spinning reserve or loss of hot standby energy. PV system power production efficiency and reduce consumption should be taken into account due to grid connected photovoltaic system provides power unit has led to the use of utilities to reduce the number of hours to bring efficiency losses. As the power system as a race together, connected to the electricity transmission grid photovoltaics would be contrary to the interests of other producers of electricity, which is that policymakers must consider. VGP-BPS9/S VGP-BPS9/B VGP-BPS9A

Photovoltaic effect caused by emission reductions should take into account the heat of sulfur dioxide and carbon dioxide must be solved, because when the photovoltaic system connected to the grid even considering the safety stability and economic exploitation, not only often help reduce only power plant, considering spinning reserve, hydroelectric power to bear not only the task of spinning reserve (hydro perform their task of spinning reserve less damage).

6. To run the programming

When the system then there are scattered power supply after the power system to improve system reliability and security, hoping to right the system output of photovoltaic power generation for remote programming. At present, China is Changwangfenkai the initial phase of the electricity market, only plants of large-scale electricity to participate in regional / provincial tendering market power, while scattered power from the local programming of grid electricity. VGP-BPS10 VGP-BPS10A VGP-BPS10A/B The electrical power distribution system as a whole consists of two parts: the province’s electricity grid and distributed food. The face of the variable price and the high number of scattered power, regional power grid to a variety of security constraints to meet the requirements of the most economical way of scheduling decentralized energy will be a concern.