Three principles of solar off grid system design

1.According to the load type and power of the user to confirm the power of the solar off grid inverter, the household load is generally divided into inductive load and resistance load. The load of the washing machine, air conditioner, refrigerator, pump, smoke pump and so on is inductive load, and the starting power of the motor is 5-7 times of the rated power. When calculating the power of the inverter, the starting power of these loads should be taken into account. The output power of the inverter is greater than that of the load. For monitoring stations, telecom stations and other stringent requirements, the output power is based on the sum of the load power. But for poor families in general, considering that all the loads can not be opened at the same time, in order to save cost, the sum of the load power can be multiplied by the coefficient of 0.7-0.9.
2.Confirm component power according to user’s daily power consumption. The design principle of the component is to meet the daily demand for the load per day under the average weather conditions, that is to say, the annual power generation of the solar cell component is equal to the full year load of the load. Because the weather conditions maybe below or above the average, the solar cell components are basically designed to meet the needs of the worst season of light, that is, in the worst season, the battery can also be basically full of electricity every day. But in some areas, the worst season illumination is far below the annual average. If the power of the solar cell component is designed in the worst case, the power generation at other times of the year will be far more than the actual demand, causing waste. At this time, we can only consider increasing the design capacity of the battery and the storage of electric energy, make the battery in the shallow discharge state, make up the damage caused by the shortage of electricity generation in the worst season. The power generation capacity of the component can not be completely converted into electricity. The efficiency of the controller and the loss of the machine and the loss of the battery are also considered. The solar controller has two types of PWM and MPPT. The efficiency of the PWM controller is about 85%, the input voltage range is narrow, but the price is low, the efficiency of the MPPT controller is about 95%, and the price is higher. In the course of charging and discharging, the battery also has 10-15% loss.
3.The battery capacity is determined according to the user’s night power consumption or expected waiting time. The task of battery is to ensure the normal load of system load when the amount of solar radiation is insufficient. For important loads, it is necessary to ensure the normal operation of the system within a few days, and consider the continuous rainy days. For general loads such as solar street lamps, it can be selected within 2~3 days according to experience or need. Important loads such as communication, navigation, hospital treatment and so on are selected within 3~7 days. In addition, the installation location of the photovoltaic power system should be considered. If it is in a remote place, the capacity of the battery should be larger, because the maintenance personnel will take a long time to arrive at the scene. In practical application, some mobile communication base stations are not convenient to go to a high mountain high road. In addition to the normal battery group, it is also equipped with a set of reserve battery. For the poor families, the price is mainly considered, and the rainy days are not considered, and when the sun is good. When the sun is not good, use it less. When choosing a load, try to use energy-efficient devices such as LED lights and variable frequency air conditioners. The design of storage battery mainly includes the design and calculation of battery capacity and the design of series and parallel connection of battery pack. Most of the photovoltaic power generation systems are lead-acid batteries. Taking into account the life of batteries, the average discharge depth is 0.5-0.7.

SSP3118C off grid solar inverter specifications 1-5KVA

1. Pure sine wave inverter
2. Cold start function
3. Remote panel available
4. Auto restart while AC is recovering
5. Overload and short circuit protection
6. Compatible to mains voltage or generator power
7. Selectable charging current based on applications
8. Configurable AC/Solar input priority via LCD setting
9. Built-in MPPT/PWM (Optional) solar charge controller
10. Smart battery charger design for optimized battery performance
11. Parallel operation with up to 6 units only available for 4KVA/5KVA
12. Selectable input voltage range for home appliances and personal computers

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