Solar photovoltaic power generation is a new type of power generation technology that directly converts solar radiation energy into electrical energy. The solar radiation energy is converted into electrical energy through solar cells, and then through energy storage, control and protection, energy conversion, and other processes, it can provide DC or AC power to the load according to people's needs. The electricity emitted by solar cell arrays is direct current, but most electrical devices use AC power supply, so an inverter is required in the system to convert direct current into AC power for the load to use.
In photovoltaic power generation systems, the efficiency of inverters directly affects the efficiency of the entire system. Therefore, the control technology of inverters in solar photovoltaic power generation systems has important research significance. In the design of inverters, analog control methods are usually used. However, there are many defects in analog control systems, such as aging and temperature drift effects of components, sensitivity to electromagnetic interference, and the use of a large number of components.
A typical analog PWM inverter control system uses the natural sampling method to compare the sinusoidal modulation wave with the triangular carrier wave to control the trigger pulse. However, the triangular wave generation circuit is prone to interference from factors such as temperature and device characteristics at high frequencies (20kHz), resulting in adverse effects such as DC offset, increased harmonic content, and changes in dead time in the output voltage. The development of high-speed digital signal processors has made digital control of inverters in solar photovoltaic power generation systems possible. Because most of its instructions can be completed in a instruction cycle, it can realize more complex advanced control algorithms, further improve the dynamic and steady performance of the output waveform, and simplify the design of the entire system, so that the system has good consistency.
Inverter is a power electronic circuit that can convert direct current from a solar cell array into alternating current to supply AC loads. It is a key component of the entire solar power generation system. Photovoltaic inverters have two basic functions: one is to provide electrical energy for completing DC/AC conversion to AC loads, and the other is to find the optimal working point to optimize the efficiency of solar photovoltaic systems. For specific solar radiation, temperature, and solar cell types, solar photovoltaic systems have a unique optimal voltage and current, allowing the photovoltaic power generation system to emit maximum power.