Off-grid inverter and grid-connected inverter working principle _ grid-connected inverter how to use off-grid

This article first introduced the working principle of off-grid inverters and grid-connected inverters, followed by a description of how to distinguish grid-connected inverters and off-grid inverters. Finally, we introduced how grid-connected inverters are used off-grid. Follow the specific Xiao Bian together to find out.

Grid-connected inverters are generally classified into photovoltaic grid-connected inverters, wind-power grid-connected inverters, power generation grid-connected inverters, and other power generation equipment. The most important feature of grid-connected inverters is their high power and low cost.

Grid-connected inverters are generally used in systems with large-scale photovoltaic power stations. Many parallel PV strings are connected to the DC input of the same centralized inverter. Generally, high-power three-phase IGBT power modules are used, and the power is relatively low. The small use of field effect transistors, while using a DSP switching controller to improve the quality of the power produced, makes it very close to a sine wave current.

Off-grid Inverter The complete system solution using modular components Xantrex XW consists of several manageable building blocks: XW inverter/charger, solar charge controller, automatic generator start-up module, and system control board.

First, photovoltaic inverters, also known as photovoltaic inverter power regulators, can be divided into two types: stand-alone (off-grid) and grid-connected, depending on the use of inverters in the distributed blue-sky photovoltaic power generation system. The types of classification are mainly divided by the use of photovoltaic power generation systems. There is no need to investigate them. It is only necessary to know that Jiaotong University`s blue sky photovoltaic power generation can be divided into two types according to different uses of photovoltaic systems.

The second is based on the inverter's own waveform modulation method can be divided into square wave inverters, step-wave inverters, sine wave inverters and combined three-phase inverters, which is the production of inverters in the National Tsinghua University The waveform of the device itself is divided.

The third is divided into transformer-type inverters and transformer-less inverters based on the photovoltaic grid-connected systems used in Jiaotong University. This is mainly a classification of photovoltaic inverters from different requirements of grid-connected systems.

Grid-connected inverters can be used directly as off-grid inverters

Grid-connected inverters send energy directly to the grid, so tracking the frequency and phase of the grid is equivalent to a current source. Of course, there are also some inverters that have low-voltage ride-through capability and can do PQ adjustment.

The off-grid inverter is equivalent to establishing an independent small grid, mainly controlling its own voltage, which is a voltage source.

Grid-connected inverters do not require energy storage, but their energy is not regulated. How much of the PV is sent to the Internet will not depend on people's needs. The grid does not like it.

Off-grid energy storage is generally required, not to send energy online. The power grid has no right to interfere.