1 off-grid photovoltaic power generation system Off-grid photovoltaic power generation system is also called independent photovoltaic power generation system, and Figure 4 is a typical structural diagram. The battery in Figure 4 is an indispensable energy storage device in the off-grid photovoltaic power generation system. The photovoltaic array is powered by the solar light, and the battery is efficiently and quickly charged by the controller and the DC/DC converter; The electrical energy can be fed to the DC load through the arrester or to the AC load via DC/AC conversion. The controller realizes MPPT by adjusting the equivalent load of the PV array according to the current working condition by controlling the DC/DC converter; on the other hand, the controller adopts sine wave modulation (SPWM) or space vector pulse width modulation (SVPWM) technology. The voltage source type DC/AC inverter is controlled to output a stable, reliable AC power with a low total harmonic distortion rate. Anti-back charge diodes prevent the battery from discharging to the PV array to prevent reverse current damage to the PV array. Off-grid photovoltaic power generation system is mainly used to stay away from the public power grid. Household photovoltaic systems with small areas or small capacity (generally no more than a few hundred watts). 2 grid-connected photovoltaic power generation system The grid-connected photovoltaic power generation system is connected to the public power grid, and its typical structure is shown in Figure 5. In Figure 5, the pre-stage DC/DC conversion control for MPPT is independent of the DC/AC PWM control for inverter and grid-connected control, which reduces the interaction between the grid-connected operation of the inverter and the output power of the PV array. In mention At the same time of high solar energy utilization, the grid-connected current quality is improved. The grid-connected photovoltaic power generation system has the advantages of high solar energy utilization rate, omission of battery energy storage, and significant reduction in power generation cost compared with independent photovoltaic power generation. It is a trend of photovoltaic power generation technology, mainly including large-scale connected photovoltaic power stations and residential networking. There are two major types of photovoltaic systems. Among them, residential roof-connected photovoltaic systems combined with photovoltaic systems and buildings (BAPV) have become a hot spot in the photovoltaic industry. The key technologies of grid-connected photovoltaic power generation systems include photovoltaic array MPPT, inverter, grid-connected control, grid-connected protection and islanding effect detection. in accordance of the Voltage range of the inverter, the PV boards can be installed in series to meet the input voltage of inveter, and several such series to be installed in parallel, to input into the combiner. The current goes through lightenling protection and breaker equipment, then ouput for connection with inverter. We strongly suggest the users to follow all the necessery safety regulation, take all the safefy masures mentioned in the manual, to lower the possibility of danger, make sure of the personal safety. Jinan Xinyuhua Energy Technology Co.,Ltd , https://www.xyhenergy.com
