The off-grid solar power system design is different from the grid-tie solar power system. The former needs to take into consideration many factors including the load, daily electricity quantity local climate conditions, and so on, to choose different design plans according to clients’ practical demands. Therefore, the off-grid solar photovoltaic system is comparatively complex. To ensure the reliability of the off-grid PV system, a thorough survey of customer demands is very necessary. The design of an off-grid solar power system is mainly composed of the inverter selection, solar panel capacity, and battery capacity.
Now we take a design of an off-grid solar power system for a small-scale fish farmer near a lake as a case study. Due to the long-distance power grid construction, not only is the cost high, but the power loss and voltage loss of the wires are also huge. Meanwhile, the stability of power use cannot be ensured because typhoons and accidental power failures happen on a frequent basis, which can affect the power used for production and life. Therefore, the off-grid solar power system is adopted. The sunlight radiation intensity in the daytime is high, and the power generated by the solar power system is directly provided to the solar inverter output to support the operation of electric devices. At the same time, the batteries are charged, and provide the power for the devices via the inverter at night.
In fact, there is a close connection between the photovoltaic power generation capacity and the grid voltage. The power generation capacity gap between regions with extremely unstable voltage and regions with stable voltage is around 10% to 20%. This paper mainly discusses the influence of the grid voltage on the system. The grid voltage can be divided into three conditions, namely low voltage, high voltage and dramatic voltage fluctuation. These three conditions will all influence the system’s power generation capacity.
To a solar energy grid-tie system, the time and climate will cause changes of solar radiation, thus resulting in constant changes of the power point voltage. In order to improve the generating capacity, and ensure that the solar panels can output the highest power, either when the sunshine is weak or when the sunshine is strong, the solar inverter usually introduces the boost circuit to expand the voltage of its working point.
The off-grid photovoltaic power generation system for household use consists of the photovoltaic module, supporter, controller, solar inverter, accumulator and power distribution system. The system's electric plan design should take the selection and computing of modules, inverters (controllers), and accumulators into consideration. Before the plan design, necessary preparation should be made, because the off-grid is customized without a unified plan. Therefore, the user load type and power, electricity consumption in the daytime and in the evening, and climate conditions of the installation place should be first learned. The power supply for the off-grid photovoltaic system relies on the weather, which is not 100% reliable.
The solar power system is used to convert the solar energy directly into the electric power via the solar cell module. The solar cell module is a solid device, which makes use of electronic characteristics of semiconductor materials to realize P-V conversion. In many areas without the power grid, the solar photovoltaic system can facilitate the lighting and domestic power supply for users. In some developed areas, it can be connected with the regional power grid to realize complementation. Then, how does the solar PV system work to generate the electricity used in our daily life?
300W-1400W solar micro inverters from inverter.com adopt IP67 waterproof streamline appearance design, which can effectively prevent rain erosion on the surface, and has built-in high-performance Maximum Power Point Tracking (MPPT) function, which can better track the changes of solar photometry and control different output power, effectively capture and collect sunlight. Reverse AC power transmission technology is one of our patented technologies. The power output from micro inverters can be used preferentially to provide load. The endless power is transmitted to the power grid in the opposite direction. The power output from inverters can be used efficiently, and the power transmission rate can reach more than 99%. To show you what you can expect, we've outlined a simple six-step guide for a typical solar microinverter installation process.
A solar inverter functions to convert the variable direct current (DC) output generated by PV solar panels into the alternating current (AC) which is fed into a commercial electrical grid or used by a local, off grid electrical network. Buy the right product for a particular application is very important and there are many factors that go into selecting the best solar inverter. Here are 8 key instructions that you may follow in order to choose the best suited solar inverter for you.
In the photovoltaic system, the cost of the solar inverter is less than 5%, but it is one of the decisive factors of power generation efficiency. When the accessories such as the component are completely consistent, if different inverters are selected, the total power generation capacity of the system has a difference ranging from 5% to 10%. Such a difference is mainly caused by the inverter. The MPPT efficiency is the key factor determining the PV inverter power generation capacity, and its importance even exceeds the efficiency of the PV inverter itself. The MPPT efficiency is equal to the hardware efficiency multiplied by the software efficiency. The hardware efficiency is mainly determined by the accuracy of the sampling circuit, the MPPT voltage range and the number of MPPT paths. The software efficiency is determined by the control algorithm.
The photovoltaic solar inverters are classified into grid-tie inverters, off-grid inverters, and microgrid energy storage inverters according to their different applications. The grid-tie inverters can be further classified into micro inverters, string-type inverters, concentrated inverters and centralized distributing inverters according to power and usage. The micro inverter has the power class of 180W to 1200W, thus being suitable for small power generation system. The string-type inverter is the single-phase inverter with power from 1kW to 5kW. It is suitable for household power generation system. The three-phase inverter with the grid-tie voltages of 220V, 5kW to 70kW is suitable for industrial and commercial power generation systems. Its on grid voltage is three-phase 380V.
