Off-grid solar inverters can work independently after leaving the grid, which is equivalent to an independent small grid. It is also similar to a voltage source, which mainly controls its own voltage. Off-grid inverters can be loaded with resistance and capacitance, inductive motors, and other loads. It has quick response, anti-interference, strong adaptability, and practicability features, and is the preferred power supply for power failure and outdoor power supply.
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.
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 photovoltaic off-grid power generation system is mainly used to solve the basic electricity consumption problem for residents in areas without electricity or insufficient electricity. The photovoltaic off-grid power generation system is mainly constituted of the photovoltaic component, bracket, controller, power inverter, storage battery and power distribution system. Compared with the photovoltaic grid-connected system, the off-grid system has an additional controller and storage battery. In addition, the inverter directly drives the load, so the electrical system is more complicated. Since the off-grid system may be the only power source of the user and the user relies more on the system, the off-grid solar system design and operation must be more reliable.
In off-grid photovoltaic (PV) systems, choosing the right inverter is a crucial step. The inverter not only determines whether the system can function properly but also directly impacts the system's efficiency, stability, and cost. Home Power Inverter will discuss the principles of selecting inverters for off-grid PV systems, the characteristics of different types of inverters, and their application scenarios, providing readers with a detailed professional guide.Â
