Why is the starting voltage of the grid tie inverter higher than the minimum voltage?
In photovoltaic grid-tied inverters, there is a strange parameter, that is, the input starting voltage of the inverters, which is about 30V higher than the minimum operating voltage. For example, single-phase inverters, MPPT operating voltage is 70V to 550V, starting voltage is 100V. Many people wonder whether the grid tie inverters work or not from 70V to 100V. If it is working, but the inverters need 100V to start.
In fact, the reason why the starting voltage is higher than the minimum working voltage is based on the characteristics of photovoltaic modules. Before the solar inverter starts, the components do not work and are in the open circuit state. The voltage will be relatively high. When the inverter starts, the components are in the working state and the voltage will be reduced.
If three components are connected in series, when the sun shines in the morning, the open-circuit voltage may be 90V. If it starts at this time, it may only be 60V. If it does not reach the working voltage, the inverters will stop. Only when the open-circuit voltage exceeds 100V, if it starts at this time, the working voltage will exceed 70V, the inverters will work all the time.
After the solar inverters start up, it does not mean that the inverter will have power output immediately. The control part of the inverters, CPU, screen and other devices work first. First, the inverters are self-checked, then the components and power grid are detected. After no problem, the output of the inverters will only be achieved when the photovoltaic power exceeds the standby power of the inverters.