Principle of Structure of a Solar Energy Inverter

In the process of constructing and operating a photovoltaic power plant, the inverter in the electrical equipment plays a very important role. Like the photovoltaic power generation system technology, it continuously improves the operating efficiency and conversion power, forming the most efficient photovoltaic system together with photovoltaic components and other power generation equipment.

Introduction of Solar Electric Inverter

Generally, the process of converting AC energy into DC energy is called rectification, the circuit that completes the rectification function is called the rectification circuit, and the device that implements the rectification process is called the rectification equipment or rectifier. Correspondingly, the process of converting DC energy into AC energy is called inversion, the circuit that completes the inversion function is called the inversion circuit, and the device that implements the inversion process is called the inversion equipment or inverter. The inverter, also known as the power conditioner, can be divided into independent power supply and grid-connected types according to its use in the photovoltaic power generation system. The solar energy inverter can be divided into square wave inverter, ladder wave inverter, sine wave inverter and combined three-phase inverter according to the waveform modulation method. For inverters used in grid-connected systems, they can be divided into transformer-type inverters and non-transformer-type inverters according to whether they have transformers. There are various types of inverters, so special attention should be paid when choosing the model and capacity. Especially in solar power generation systems, the efficiency of solar energy inverters is an important factor in determining the size of solar cell and battery capacity.

Understand the Structure and Principle of Solar Electric Inverter

The solar energy inverter is a power adjustment device composed of semiconductor devices, mainly used to convert DC power into AC power. It is generally composed of a boost circuit and an inverter bridge circuit. The boost circuit boosts the DC voltage of the solar cell to the DC voltage required for the inverter output control; the inverter bridge circuit then converts the boosted DC voltage equivalently into AC voltage of common frequency.

The inverter is mainly composed of switch elements such as transistors, which convert DC input into AC output by regularly repeating ON and OFF of the switch elements. Of course, the output waveform of the solar energy inverter generated solely by the on/off circuit is not suitable. Generally, high-frequency pulse width modulation (SPWM) is used to narrow the voltage width near the sine wave ends and widen the voltage width in the center of the sine wave, and the switch elements are always moved in one direction at a certain frequency during half a period, thereby forming a pulse wave column (quasi-sine wave). Then let the pulse wave pass through a simple filter to form a sine wave.