Inverter power supply according to transform methods can be divided into power frequency transform and high frequency transform. Power frequency conversion is produced by using discrete device or integrated block 50 hz square-wave signal, and then using the signal to push the power switch tube, using the step-up transformer produces 220 v ac power frequency.
This kind of inverter power supply has simple structure, reliable work, but because of the defects of circuit structure itself, is not suitable for inductive load, such as refrigerators, electric fan, water pump, fluorescent lamp, etc. In addition, this kind of inverter power supply has adapted the power frequency transformer, so with big volume, too heavy, and high price disavdanteges. Mainly used in large-scale solar photovoltaic power plant at present.
In the early 1970 s, 20 KHZPWM type switching power supply applications in the world caused a so-called "20 KHZ power technology revolution". This transformation idea was used in inverter power supply system, due to the power electronic IC is quite expensive, and large loss, high frequency inverter power supply efficient research has stopped. After in the 80 s, with the power MOSFET process mature and the improvement of magnetic material quality, the high frequency conversion inverter power supply come to the market again.
High frequency conversion inverter power supply through the high frequency DC/DC conversion technology, firstly turns low voltage DC into high frequency lowe voltage AC, on the booster pulse transformer rectifier again make into a high voltage DC. Due to the PWM technology is adopted in DC/DC conversion, thus get a stable DC voltage, and this voltage can be driven directly by using the communication energy-saving lamps, incandescent lamps, TV and load.
If the class of the high voltage dc sine transform or sine transform, can get 220 v, 50 hz sinusoidal alternating current (ac) or 220 v, 50 hz sinusoidal alternating current. The inverter with high frequency transform (now for more 20 KHZ to 200 KHZ) small volume, light weight, and with two adjustable width and secondary voltage regulation technology, thus the output voltage is very stable, strong load capacity, high cost performance, which it is the first choice in renewable energy power generation system products.
The small and medium-sized pv systems widely used in foreign developed countries, but in China, due to technical reasons and the market turmoil, some of the inverter power supply manufacturer has been in the promotion of power frequency conversion inverter power supply, some in order to reduce costs even using low silicon silicon steel sheet, the inverter power supply flooding the market, raising the comprehensive cost of the ac photovoltaic system, Hence the photovoltaic system will hinder communication, it is bad for the development of the industry.