Solar Grid Tie Inverter Working Principle
Wednesday, January 27, 2021
In addition to the DC-AC conversion function, the solar grid tie inverter shall also own the solar cell array MPPT function and various protection function. The solar cell array delivers power energy to the power grid through sine wave PWM inverter. The power sent from the solar on grid inverter to power grid is determined by the solar cell array power and local sunshine conditions of the specific time. Now, power inverter technology becomes very mature. The work principle: When the power supply of the utility grid is stopped, the grid side will stay in short-circuit status. At this time, the grid tie solar inverter will start self-production function because of the overload problem. When the overload situation is detected by the microprocessor, it will block the SPWM signal and will trigger the circuit breaker connected with the power grid. If the solar cell array can output energy, grid tie solar inverter will operate separately, which can be controlled easily. It only needs to know the negative feedback status of the AC voltage. The microprocessor will detect the output voltage of solar grid tie inverter and compare it with the reference voltage (normally is 220V). Then, it will control the PWM output duty cycle to realize inverting and stable-voltage operation.