subject: Knowledge Of Solar Design - Solar Photovoltaic System Design - China Projector Lens [print this page] First, PV systems of classification: First, PV systems of classification:
1. Independent Solar Power Supply System
2. Simple DC System
3. DC - AC Power Supply System
4. And network system
5. Hybrid power supply system (scenery, varnish, etc.)
Can not so classified, I like so minutes.
Second, the composition of PV systems:
Solar cells, charge and discharge controller, inverter, computer monitors, batteries, etc..
Third, the capacity of PV system design:
Includes load power consumption estimates, estimate the number of solar cells, battery capacity calculation, the best angle and so placed.
1. Calculation of battery capacity
Here to talk about the next several concepts:
Self-sufficiency in the number of days: I do not understand is where the sun can also work the number of days. Generally available in the local maximum continuous rainy days as a self-sufficient number of days.
Maximum discharge depth: maximum depth of discharge the battery to allow more than this depth will not work, usually a fixed value.
Basic formula: (daily load electricity self-sufficiency in the number of days *) / maximum depth of discharge = battery capacity
And battery capacity in which the two factors: the battery discharge rate and temperature, considering these two factors would be more complex points.
Batteries and dry cells in series and parallel is the same, do not say.
2. PV square design:
Basic formula:
= Daily average number of parallel load / components on the output
Serial number = system voltage / component voltage
If the amendment would need to be more accurate, usually solar cell output by 10% and 10% of the load increase
Calculate the best angle and to involve more than symbols, these symbols not willing to write.
4, photovoltaic systems infrastructure, hardware design, grounding and lightning protection design and so on.
5, electronic circuit part
Including the charge and discharge controller, inverter, remote technology (remote control, remote, telemetry, remote adjustment) of the applications.
1. Controller
Photovoltaic system controller is the most important, that is to small to zero a few watts of the courtyard, large trillion-level system should have the part, just simple and complicated points, their aim the same. Are for the normal work load to the power to normal power supply, battery charger in time. This purpose can be achieved in different power electronic components, such as the three tubes, relays, integrated operational amplifier, GTO, mosfet, SCM, etc., I will talk about several following controllers:
simple solar charging circuits
The reason listed first because it is not only simple to make another point is that it was my first exposure to a solar controller circuit, but also vaguely remember when I took a pencil drawing of the circuit with only electronic components to the home shops to buy components, the boss do not understand the above relay symbol, insisting that my drawing was wrong. I have enough of bt, and went home again and looking at art not wrong, then go to the boss theory. Later school, and four ahead to buy the components I finally under one roof, in the laboratory borrowed a bread board, debugging and again welding. Unfortunately, at that time can not buy one in Wuhan, solar panels (now seems to buy), while made a semi, but the dream of solar energy from me the first step, say a few words, get down to business.
Picture as follows:
(You can not see that this look: http://tu.cndzz.com/Upload/200552595758485.jpg)
This is a non-stop to the 12v battery charging circuit. Figure D1 (5A) is anti-charge diodes, photovoltaic systems is necessary device is to prevent current flowing back; LM317 is to provide 5v of power integrated block; J1 and J2 are two relays, relays are usually normally closed normally open state and the state; here compared to LM393 Used when the voltage; RP1 and RP2 are used to set off the user charge and deep discharge voltage. Voltage comparator and relay to continuous charging purposes.
Another online charging circuit
Solar lamp circuit as shown in the circuit is a low loss, using a 7W 4-pin CFL (compact fluorescent) and a 12V ,7-Ahr sealed maintenance-free battery. Inverter efficiency greater than 85%, quiescent current is less than 2mA. It has a battery over discharge protection * Gong * can and overcharge protection * Gong * can parallel charge controller. Low quiescent current, discharge protection * Gong * can and overcharge protection * Gong * to three to ensure a long battery life. Preheat Inverter CFL * Gong * to avoid black ends, thus extending its life. This circuit can be used as a reliable in rural areas, small, portable light source for emergency lighting systems in cities. Parallel charge controller circuit consists of IC1 (low current 2.5V voltage reference LM385) and IC2 (LM324 comparator). With resistors R1 ~ R8 and the transistor Q1 of IC2A prevent excessive battery discharge.
When the battery voltage falls below 10.8V, the circuit to cut off the load (inverter and lamp) to prevent excessive battery discharge. In no load conditions, the battery voltage after discharge is about 12.2V, therefore, in order to prevent oscillation, reset circuit provided over discharge voltage 12.3V. Direct red light-emitting diode LED1 low voltage state. With a resistor R9 ~ R14 and transistor Q2 of IC2B prevents battery overcharge. When the battery voltage exceeds 14.8V when, Q2 turns on, make arrays of solar cells next to streams, thereby preventing battery overcharge. When the battery voltage falls below 12.5V when, Q2 closed cell arrays of solar panels to charge the battery. D2 is a reverse blocking diode. It can prevent the battery in solar cells do not produce electricity when solar battery discharge. Huang Faguang diode LED2 indicates that the battery is fully charged. Green light-emitting diode LED3 and IC2c and resistor R15 ~ R20 together to provide the charging indicator.
The single chip controller for the control of the core circuit
Points microprocessor circuit, power supply circuit, real-time clock circuit, liquid crystal display circuit, the charge switching circuit, the keyboard interface circuit, because there is no circuit line, I have not made the map made up, they talk about the important part of the principle of it. SCM helpful c51's also useful 96, it also pic's, all of these solar cell samples measured by the A D converter in the microcontroller communication, display circuit can be human-machine interface for control
Time clock circuit to provide output control can be realized on the street. ]
Personally think that difficulties in implementation of MPPT is the largest * Gong * rate point tracking, can improve efficiency.
