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The function of solar controller

Hits:40 comment:0 Date:2016/11/18 13:04:46 tags:全部

The solar controller called the solar charge discharge controller, is used in solar power generation system, the control of multiple solar array on the automatic control equipment of battery and battery for solar inverter load power supply.

The solar controller uses the high speed CPU microprocessor and the high precision A/D analog to digital converter, which is a microcomputer data acquisition and monitoring control system. Not only can the working state of the current rapid real-time acquisition of photovoltaic system, stayinformed PV station, and with the accumulation of PV historical data station, provides accurate and sufficient basis for the rationality and reliability test system component quality evaluation system design of PV. In addition, the solar controller also has serial communication data transmission function, can be a number of photovoltaic system sub station for centralized management and remote control.

Solar controller usually has 6 nominal voltage levels: 12V, 24V, 48V, 110V, 220V, 600V

function

1 power regulation function:

2 communication function: 1 simple function of the 2 protocol communication protocol such as RS485 Ethernet, wireless and other forms of background management

3 perfect protection function: electrical protection, short circuit, over current, etc..

Protection mode

1, direct voltage protection: directcharge also called emergency charging, which belongs to the fast charging, when the battery voltage is generally low with high current and relatively high voltage on the battery, but there is a control point, also called protection, is the numerical table, when charging the battery terminal voltage these higher protection value, should stop charging. Direct voltage protection is generally the overcharge protection point voltage, battery voltage is not higher than that of the protection charge, otherwise it will cause overcharge, there is damage to the battery.

2, charging control voltage: directcharge after the end of the battery charge and discharge controller will normally be for a period of time, so the voltage falls naturally, when the whereabouts of the "recovery voltage" value, will enter the charging state. Why should the design charge? When charging is completed, there may be some "backward" (the battery terminal voltage is relatively low, in order to get these individual molecules) to pull back, the battery end voltage of all is uniform, so it is necessary to high voltage with moderate current charging for a little while, the charge is also visible. "Equalizing charge". Charging time should not be too long, usually a few minutes to ten minutes, time is too long but harmful. For small systems equipped with a two battery, charging little significance. So, the controller has no charge, only two stages.

3, floating point voltage control: general is charging after the battery has been standing for a long time, the voltage falls naturally, when falling to "maintain voltage" point, into a floating state, similar to the "trickle charge" (small current charging), a low battery voltage charge on one point, a low charge on a point, a shares to avoid the battery temperature continues to rise, it is good for the battery, because of the great influence on the internal temperature of the battery charge and discharge. In fact, PWM mode is designed to stabilize the battery terminal voltage, by adjusting the pulse width to reduce battery charging current. This is a very scientific charging management system. Specifically, in the latter part of the battery, the storage battery residual capacity (SOC) >80%, it is necessary to reduce the charging current, in order to prevent over charging and excessive release of gas (oxygen, hydrogen and acid gas).

4, over the protection of the termination voltage: This is a good understanding. Battery discharge can not be lower than this value, which is the national standard. Although the battery manufacturers have their own protection parameters (enterprise standard or line standard), but ultimately to the national standard. Note that, for safety reasons, the 12V battery discharge protection voltage artificially plus 0.3V as a temperature compensation control circuit or zero drift correction, overdischarge protection voltage of 12V battery that is: 11.10v, then discharge protection voltage of 24V system for 22.20V.

Protection voltage

Some customers are often found in light of the solar street after a period of time, especially after the continuous overcast and rainy days, the street lamps will be for several days or even several days not bright, detect the voltage of battery is normal, controller, lights are no fault.

This problem has a lot of Engineering doubts, in fact this is the "exit under voltage protection" value, this value is set higher, the undervoltage recovery after the longer time, also caused a lot of days are not light.

Current output

LED due to its own characteristics, it is necessary to use technical means to carry out its constant current or current limiting, otherwise it can not be used properly. The LED lamp is usually through plus a driver to achieve the LED lamp constant current, but the driver has accounted for 10%-20% of the total power of light, such as a theoretical value of the LED lamp 42W, plus the driver after the actual power may be around 46-50W. In the calculation of battery power and battery capacity, must add 10% to 20% to meet caused by driving power consumption. In addition, a lot more than the driver of a fault. Industrial version of the controller through the software without power consumption constant current, high stability, reducing the overall power consumption.

Output period

Ordinary controller can only be set to turn off the lights after 4 hours or hours, such as the closure of a number of hours, has been unable to meet the needs of many customers, 8. Industrial controller can be divided into 3 periods,

Each period of time can be arbitrarily set, according to the different use of the environment, each time can be set to close state. For example, some plants or scenic areas at night, no one can be second hours (late at night) closed, or second, third hours are closed, reducing the cost of use.

output power

In the application of solar lamps, LED lamp is the most suitable for the pulse width modulation to achieve different output power. Limit or limit the current pulse width at the same time, the LED lights the output duty cycle adjustment, LED lamps such as the single 1W LED 7 series and 5 35W in total, at discharge, can be the night and early morning hours of power regulation, such as regulation, regulation of 15W at night and into 25W. Lock the current, so that you can meet the night lighting, and save the panels, battery configuration cost. After a long period of testing, the pulse width modulation mode of the LED lamp, the whole lamp to produce much less heat, can extend the service life of LED.

Some lamp factory in order to achieve the purpose of saving in the night, the LED lights into 2 way power supply, the power supply to achieve a night off road to halve the output power, but the practice has proved that the source of this method will only lead to the first half of the light, brightness is not consistent or a light road early damage.

Line loss compensation

According to the different line diameter and line length to give automatic compensation. Line loss compensation is very important in the low-voltage system, because the voltage is low, the loss is relatively large, if there is no corresponding loss compensation voltage, output voltage will be lower than the input, this will cause the early battery undervoltage protection, the application rate of battery capacity was discounted. It is worth noting that, when we use the low voltage system, in order to reduce the line loss, try not to use too thin cable, cable is not too long.

Dissipate heat

A lot of controller in order to reduce the cost, without considering the problem of heat dissipation, so the load current is greater or larger charging current, increase the heat resistance, field tube controller is increased, leading to the charging efficiency decline, field tube life is also greatly reduced after overheating even being burned, especially outdoor environment temperature in summer is very high, so heat a good device should be essential controller.

Charging mode

Charging mode of conventional solar controller is a copy of the three section type electric charger and charging method, namely, constant flow, constant pressure, float three stages. Because the city power grid energy is infinite, if not for the constant current charging, battery charging will directly lead to explosion and damage, but the solar streetlight system battery power is limited, so continue to use electricity charging mode of constant current controller is not scientific, if the current panels produced greater than the first paragraph limit controller current, then caused a decline in the charging efficiency. MCT charging battery board is to track the maximum current, no waste, by detecting the voltage of battery and calculate the temperature compensation value, when the battery voltage is close to the peak, and then take the pulse trickle charging method, which can make the battery full to prevent battery charge.


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