Photovoltaic inverter working principle

Working Principle
The core of the inverter device, is the inverter switching circuit, referred to as the inverter circuit. This circuit accomplishes the function of inverter through the conduction and shutdown of power electronic switches.

Features
(1) Requires high efficiency. Due to the current high price of solar cells, it is necessary to try to improve the efficiency of the inverter in order to maximize the use of solar cells and improve the efficiency of the system.

(2) Requirement of high reliability. At present, PV power station systems are mainly used in remote areas, many power stations are unmanned and maintenance, which requires the inverter to have a reasonable circuit structure, strict component screening, and requires the inverter to have a variety of protection functions, such as: input DC polarity reversal protection, AC output short-circuit protection, overheating, overload protection and so on.

(3) Require a wide adaptation range of input voltage. As the terminal voltage of the solar cell changes with the load and sunlight intensity. Especially when the battery aging its terminal voltage changes in a wide range, such as 12V battery, its terminal voltage may vary between 10V ~ 16V, which requires the inverter in a wide range of DC input voltage to ensure normal operation.

Inverter Classification

Centralized, String, Distributed and Micro.

According to different dimensions such as technology route, the number of phases of output AC voltage, energy storage or not, and downstream application areas, you inverters will be categorized.
1. According to the energy storage or not, it is divided into PV grid-connected inverter and energy storage inverter;
2. According to the number of phases of the output AC voltage, they are divided into single-phase inverters and three-phase inverters;
3. According to whether it is applied in grid-connected or off-grid power generation system, it is divided into grid-connected inverter and off-grid inverter;
5. according to the type of PV power generation applied, it is divided into centralized PV power inverter and distributed PV power inverter;
6. according to the technical route, it can be divided into centralized, string, cluster and micro inverters, and this classification method is more widely used.