What is a solar inverter?
Inverters, also known as power regulators or power regulators, are an essential part of photovoltaic systems. The main function of photovoltaic inverters is to convert the direct current generated by solar panels into alternating current for household use. All the electricity generated by solar panels must be processed by the inverter before it can be output to the outside world.
Through a full bridge circuit, an SPWM processor is generally used to modulate, filter, boost, etc., to obtain sinusoidal AC power that matches the lighting load frequency, rated voltage, etc., for use by end users of the system.
With an inverter, DC batteries can be used to provide AC power to electrical appliances. The Yangneng AC power generation system is composed of solar panels, charging controllers, inverters, and batteries; The solar DC power generation system does not include inverter.
The process of converting AC electrical energy into DC electrical energy is called rectification, the circuit that completes the rectification function is called rectification circuit, and the device that implements the rectification process is called rectification equipment or rectifier.
Correspondingly, the process of converting DC electrical energy into AC electrical energy is called inversion, the circuit that completes the inversion function is called inversion circuit, and the device that implements the inversion process is called inversion equipment or inverter.
The core of the inverter device is the inverter switch circuit, abbreviated as the inverter circuit. This circuit completes the inverter function by conducting and turning off power electronic switches. The on-off of power electronic switching devices requires certain driving pulses, which may be regulated by changing a voltage signal.
The circuit that generates and regulates pulses is commonly referred to as a control circuit or control loop. The basic structure of an inverter device includes not only the inverter circuit and control circuit mentioned above, but also protection circuit, output circuit, input circuit, output circuit, etc.
The functions and effects of solar inverters
Inverters not only have the function of DC/AC conversion, but also have the function of maximizing the functionality of solar panels and maintaining system faults.
It can be summarized as active operation and shutdown function, maximum power tracking control function, anti independent operation function (for grid connected systems), active voltage adjustment function (for grid connected systems), DC detection function (for grid connected systems), and DC grounding detection function (for grid connected systems). Here is a brief introduction to the functions of active operation and shutdown, as well as the maximum power tracking control function.
1.Active operation and shutdown function:
After sunrise in the morning, the solar radiation intensity gradually increases, and the output of the solar panel also increases. When the output power required for the inverter task is reached, the inverter starts to operate actively.
After entering operation, the inverter will constantly monitor the output of the solar panel. As long as the output power of the solar panel is greater than the output power required for the inverter task, the inverter will continue to operate; Until sunset, the inverter can still operate even on cloudy and rainy days. When the output of the solar panel decreases and the inverter output approaches 0, the inverter forms a standby mode.
2.Maximum power tracking control function:
The output of the solar panel changes with the intensity of solar radiation and the temperature of the solar panel itself (chip temperature). Because solar panels have the characteristic of voltage decreasing with increasing current, there exists an optimal task point to obtain maximum power.
The intensity of solar radiation is changing, and the optimal task point is clearly also changing. Regarding these changes, the task point of the solar panel has always been at the maximum power point, and the system has always obtained the maximum power output from the solar panel.
This control is called maximum power tracking control. The biggest feature of the inverter used in solar power generation systems is that it includes the function of Maximum Power Point Tracking (MPPT).
