Smart solar inverter
It’s the link to the smart grid. The solar inverter should have high advanced communication capability with smart grid in addition to analytic, computing and memory capabilities to provide all information and control features to the smart grid energy management system.
Off grid solar system is more complex in installation than on grid solar system, as it requires more components like charge controller and batteries, so it needs higher technical skills and costs more. Although of this, off grid solar system market grows and most of suppliers / manufacturers try to save the cost and complexity by searching and implements new techniques and services that you should pay attention for as following.
Many people working in solar industry knows about MPPT acronym, but few of them understand correctly, although it is an important feature that helps us increasing solar photovoltaic energy harvest. Simply put, it is DC to DC converter incorporated inside most of all modern solar photovoltaic inverters that enable maximizing DC energy harvest getting from solar panels at any time during the operation cycle.
Off grid solar inverter converts DC electricity comes from solar panels and stored in Batteries to AC electricity to be used to run all of AC loads types existing now like TV, refrigerator, oven, lights, air conditions…etc. What are parameters to check when buying the off-grid inverter?
Today we see many solar plants connected to the power grid, and there will be more and more in near future. All experienced power system engineers, and operators see that it is a must for these solar plants to have sophisticated control system to achieve coordination and integrity between them and other traditional power plants exist in the grid. This smart control system can be done only through solar inverters which represent the brain of the solar power plant.
Today, the new frontier of solar inverters become exist everywhere, it's the smart solar inverter which has the ability to interact with the power grid. It has internal advanced software that enable performing amazing actions. The smart solar inverter is able to connect with the grid even with the presence of disturbances like voltage changes, the inverter automatically switches from operating mode to standby mode, then operating mode or even turn off if the disturbances last for long time.
Today we will introduce a home solar power system design below 10kW, which is installed on the roof of the house and connected to the grid of 220V or 380V. The maximum installation capacity is 25% of the capacity of the upper-level transformer. First of all, it is required to determine whether the load capacity of the roof can meet the requirements. The loading requirements of the solar power system equipment for the roof are greater than 30kg/m2.
With the constantly advance of industrial and commercial photovoltaics, there are less and less large-scale, flat, facing, unshielded cement or colored steel roofs, and the rest may be multi-angle, multi-oriented, sheltered, multi-structural roofs. How to design solar panel system on the complex roofs? The most concerned issue for designers and investors is to control the cost, ensure the power generation, and be safe and reliable.
The solar PV system is not only environmentally friendly, but also saves money and makes money, becoming a best choice of alternative or backup power source for many families. However, it need proper maintenance, so as to ensure the generating capacity of the system, and guarantee the service life. Do you want a better power generating efficiency and a longer service life of your home solar power system? It should be guaranteed by the sound maintenance.
The solar PV system is constituted by the solar cell, storage battery pack, charge controller, inverter, AC power distribution cabinet, lightning protection system, combiner box, DC power distribution cabinet, environmental monitoring system, monitoring system and other devices. The following is the overview of the main components of a solar PV system.
The light storage system includes solar energy components, controllers, solar inverters, batteries, loads and other equipment. At present, there are many technical routes, but the energy needs to be gathered on a certain point. At present, there are mainly two kinds of topological structures: DC coupling and AC coupling.
Leakage current of the photovoltaic system, which is also known as the square matrix residual current, is essentially a kind of common mode current. The cause is that there is parasitic capacitance between the photovoltaic system and the earth. When the parasitic capacitance-photovoltaic system-grid forms a loop, the common mode voltage will produce the common mode current on the parasitic capacitance. When the photovoltaic system is equipped with a industrial frequency transformer, because of the relatively high parasitic capacitance between the transformer windings in the loop, the common mode current generated by the common mode voltage in the loop can be suppressed to a certain extent. However, in a photovoltaic system with no transformer, the loop impedance is relatively low, and the common mode voltage will form a large common mode current, ie, leakage current, on the parasitic capacitance between the photovoltaic system and the earth.
Most of the PV inverters on the present market are generally in the IP65 protection level, with a certain degree of wind, dust and water resistance. However, in the summer, the ambient temperature is high, and various components in the inverter are prone to high temperatures during operation, resulting in a decrease in power generation efficiency and even affecting the service life of the components. Therefore, the inverter in some photovoltaic systems is installed with a sunshade to reduce the temperature of the equipment. In addition, the installation environment of the inverter should be well shaded and ventilated to ensure the convection of the air and also increase the power generation capacity of the power station
The energy flow path of the solar PV system usually contains a solar panel, a combiner box, a DC power distribution cabinet, a grid-tie inverter, an AC power distribution cabinet, and the connection cables. Based on the energy flow of the PV system, it is necessary to fully consider some important factors affecting the conversion efficiency in the design of the solar power system.
The installation scheme of common ground distributed projects is to install near a string of components at the closest. It adopts the fixed-rack installation or hoop-type installation to directly fix the equipment on the stand column. If this kind of scheme is used, it is required to pay attention to the strength of the rack and column, as well as the height of the solar PV inverter over ground, avoiding being submerged in stormy days because of being placed at a too low height.
The PV module capacity and solar inverter capacity ratio are commonly referred to as capacity ratio. Reasonable capacity ratio design needs to be considered comprehensively in the light of the specific project. The main influencing factors include irradiance, system loss, inverter efficiency, inverter life, inverter voltage range, assembly installation angle and so on. Because the inverter accounts for only about 5% of the system cost, the number or power of the inverter is reduced by the overmatching of the components in the distributed photovoltaic power station system, and the investment income is very small, which also bring other problems, the specific analysis is as follows.
Input overvoltage protection: When the DC-side input voltage is higher than the maximum allowable DC array access voltage of the grid tie inverter, the inverter is not allowed to start or stop within 0.1s (in operation) and a warning signal is released at the same time. After the DC-side voltage is restored to the allowable working range of the inverter, the inverter should be started and operated normally.
The micro-inverter technology directly combines the inverter with a single photovoltaic module to equip every photovoltaic module with an inverter module which is capable of DC-AC conversion and the MPP tracking. The inverter module can directly convert the power generated by the photovoltaic module into the AC for the AC load use or transmit it to the grid.
Charging controller, check the voltage setting of the rectifier and check the voltmeter to have normal indication. If the battery temperature is below 55°F (about 12.778°C), charging to a higher voltage (at least 14.8 volts for a 12 volt system) should be allowed. If your charge controller has the temperature compensation function, it will automatically adjust. If there is an external temperature sensor, please make sure that it has been attached to the battery. If there is no automatic adjustment function, it is required to manually increase the voltage and adjust back in the spring (adjust to 14.3 volts). If the charge controller is not adjustable, try to keep the battery in a warmer environment.
As one of the multiple development and utilization approaches of solar energy, solar photovoltaic power generation has the characteristics of pollution-free, renewable, flexible and storable and so on. The photovoltaic power generation system has been put into practical use in the fields of road lig...