The photovoltaic controller is an automatic control device used in the solar power generation system to control the multi-channel solar cell array to charge the battery and the battery to supply power to the solar inverter load. The photovoltaic controller adopts a high-speed CPU microprocessor and a high-precision A/D analog-to-digital converter. It is a microcomputer data acquisition and monitoring control system. It can not only quickly collect the current working status of the photovoltaic system in real time, obtain the working information of the PV station at any time, but also accumulate the historical data of the PV station in detail. sufficient basis. In addition, the photovoltaic controller also has the function of serial communication data transmission, which can perform centralized management and remote control of multiple photovoltaic system substations.
Through the use of innovative maximum power tracking technology, the photovoltaic controller can ensure the maximum efficiency of the solar array all day, all day long. It can increase the working efficiency of photovoltaic modules by 30% (the average efficiency can be increased by 10%-25%).
Also includes a search function that searches for the absolute maximum power output point every 2 hours across the entire solar panel operating voltage range.
The three-level I-U curve charging control with temperature compensation can significantly extend the life of the battery.
Lower cost solar panels with open circuit voltages up to 95V used in grid-connected systems can be used in stand-alone 12V or 24V systems through PV controllers, which can greatly reduce the cost of the entire system. Available at: MPPT100/20
role
1. Power adjustment function.
2. Communication function, simple instruction function, protocol communication function.
3. Perfect protection function, electrical protection, reverse connection, short circuit, overcurrent.
Discharge
1. Direct charging protection point voltage: Direct charging is also called emergency charging, which belongs to fast charging. Generally, the battery is charged with high current and relatively high voltage when the battery voltage is low. However, there is a control point, also called protection. The point is the value in the above table. When the battery terminal voltage is higher than these protection values during charging, the direct charging should be stopped. The voltage of the direct charge protection point is generally also the voltage of the "overcharge protection point". The battery terminal voltage cannot be higher than this protection point during charging, otherwise it will cause overcharging and damage the battery.
2. The voltage of the equalizing control point: after the direct charging, the battery will generally be left for a period of time by the charging and discharging controller to let its voltage drop naturally. When it falls to the "recovery voltage" value, it will enter the equalizing state. Why design equalizing? That is, after the direct charging is completed, there may be individual batteries "lag behind" (the terminal voltage is relatively low). The current is recharged for a short while, and it can be seen that the so-called equalization charge, that is, "equalized charge". The equalizing time should not be too long, generally a few minutes to ten minutes. If the time setting is too long, it will be harmful. For a small system with one or two batteries, equalizing doesn't make much sense. Therefore, the street light controller generally does not have equalization, only two stages.
3. Floating charge control point voltage: Generally, after the equalizing charge is completed, the battery is also left for a period of time, so that the terminal voltage falls naturally. When it falls to the "maintenance voltage" point, it enters the floating charge state. Currently, PWM is used. (pulse width modulation) method, similar to "trickle charging" (ie small current charging), when the battery voltage is low, it will be charged a little, and when it is low, it will be charged a little, and it will come one by one, so as to prevent the battery temperature from rising continuously. High, which is very good for the battery, because the internal temperature of the battery has a great influence on the charge and discharge. In fact, the PWM method is mainly designed to stabilize the battery terminal voltage, and reduce the battery charging current by adjusting the pulse width. This is a very scientific charging management system. Specifically, in the later stage of charging, when the remaining capacity (SOC) of the battery is > 80%, the charging current must be reduced to prevent excessive outgassing (oxygen, hydrogen and acid gas) due to overcharging.
4. Over-discharge protection termination voltage: This is easier to understand. The battery discharge cannot be lower than this value, which is the national standard. Although battery manufacturers also have their own protection parameters (enterprise standard or industry standard), they still have to move closer to the national standard in the end. It should be noted that, for the sake of safety, the voltage of the over-discharge protection point of the 12V battery is generally artificially added with 0.3v as the temperature compensation or the zero-point drift correction of the control circuit, so that the over-discharge protection point voltage of the 12V battery is: 11.10v, then The over-discharge protection point voltage of the 24V system is 22.20V. At present, many manufacturers of charge and discharge controllers adopt the 22.2v (24v system) standard.