The main function of the solar inverter is to convert the direct current generated by the solar panel into the alternating current used by home appliances. All the electricity generated by the solar panel must be processed by the inverter before it can be output. Through the full bridge circuit, the SPWM processor is generally used for modulation, filtering, boosting, etc., to obtain a sinusoidal AC power that matches the lighting load frequency and rated voltage for use by the system end users. With the inverter, DC storage batteries can be used to provide AC power to electrical appliances.
Function of inverter
The inverter is a power conversion device. Its main function is to invert the DC power of the battery into AC power. Through the full bridge circuit, the SPWM processor is generally used for modulation, filtering, boosting, etc., to obtain the load frequency, rated voltage, etc. The matched sine wave alternating current is used by the end users of the system.
1. Classification according to the scope of application
(1) Ordinary inverter: DC 12V or 24V input, AC 220V, 50Hz output, power from 75W to 5000W, some models have AC and DC conversion, namely UPS function.
(2) Inverter/charger integrated machine: In this type of inverter, users can use various forms of power supply to supply AC load: when there is AC power, use AC power through the inverter to supply power to the load or charge the battery; When AC power is supplied, the battery is used to supply power to the AC load. It can be used in combination with various power sources: such as batteries, generators, solar panels and wind generators.
(3) Special inverters for post and telecommunications: provide high-quality 48V inverters for post and telecommunications. The products are of good quality, high reliability, modular (module 1KW) inverters, and have N+1 redundancy functions, Expansion (power from 2KW to 20KW).
(4) Special inverter for aviation and military: This type of inverter has 28Vdc input and can provide the following AC output: 26Vac, 115Vac, 230Vac, and its output frequency can be: 50Hz, 60Hz and 400Hz, and the output power varies from 30VA to 3500VA. Wait. There are also DC-DC converters and frequency converters for aviation.
2. Output waveform classification
(1) Square wave inverter: The AC voltage waveform output by the square wave inverter is a square wave. The inverter circuits used by this type of inverter are not exactly the same, but the common feature is that the circuit is relatively simple and the number of power switch tubes used is small. The design power is generally between 100 watts and kilowatts. The advantages of square wave inverters are: simple wiring, low price and convenient maintenance. The disadvantage is that because the square wave voltage contains a large number of high-order harmonics, additional losses will be generated in load appliances with iron core inductance or transformers, which will interfere with radios and certain communication equipment. In addition, this type of inverter has disadvantages such as insufficient voltage regulation range, insufficient protection function, and relatively large noise.
(2) Step wave inverter: The AC voltage waveform output by this type of inverter is a step wave. There are also many different circuits for the step wave output of the inverter, and the number of steps in the output waveform varies greatly. The advantage of the step wave inverter is that the output waveform is significantly improved compared to the square wave, and the content of high-order harmonics is reduced. When the number of steps reaches more than 17, the output waveform can realize a quasi-sine wave. When using transformerless output, the efficiency of the whole machine is very high. The disadvantage is that there are many power switch tubes used in the stepped wave superposition line, and some of the line forms also require multiple sets of DC power inputs. This brings trouble to the grouping and wiring of the solar cell array and the equalizing charging of the storage battery. In addition, the step wave voltage still has some high-frequency interference to the radio and some communication equipment.
(3) Sine wave inverter: The AC voltage waveform output by the sine wave inverter is a sine wave. The advantages of the sine wave inverter are that the output waveform is good, the distortion is very low, the interference to the radio and the equipment is small, and the noise is low. In addition, the protection function is complete, and the whole machine is highly efficient. The disadvantages are: the circuit is relatively complicated, the maintenance technical requirements are high, and the price is relatively expensive.
The classification of the above three types of inverters facilitates the identification and selection of inverters by designers and users of photovoltaic systems and wind power generation systems. In fact, inverters with the same waveform are still very different in terms of circuit principle, use of devices and control methods.
The above is all that I have to say today. If you want to know more about solar panels, please continue to pay attention to ITEHIL. Here is a little knowledge for you. Many brands of portable solar panels and foldable solar panels do not have inverter, because their power is very small and they can directly use direct current, such as ours. ITEHIL 100W 18V foldable solar panel does not use an inverter. It can directly charge your iPhone, notebook, iPad, etc. through the charging cable, without the need for inverter adjustment.