发布时间：2020-11-30 来源：原创 浏览量：3859
A rectifier is a convertor device, which simply means to convert AC to DC. There are two main functions: one is to convert alternating current (AC) to direct current (DC) then provide a load or inverter after filtering; second, to provide a charging voltage for the battery. Therefore, it also functions as a charger.
High-power rectifier power supply requires large current capacity, high breakdown voltage and good heat dissipation performance. However, the device has a large junction area and large junction capacitance, so its operating frequency is very low, generally below tens of thousands of hertz. Silicon material has wide band gap and good thermal conductivity, which is suitable for making high-power rectifier devices. High-voltage silicon stacks are often used in high-voltage resistance rectifiers. It is composed of multiple rectifier iron cores in series. The reverse withstand voltage is determined by the withstand voltage of the iron core and the number of series iron cores. The maximum withstand voltage can reach several hundred kilovolts. If the high-frequency rectifier circuit is used at a very high frequency, when the cycle of the AC voltage is equal to the recovery time from the open state, the rectifier will not be used as a rectifier for high-frequency voltage. In order to meet the needs of high-frequency operation, gold doping is usually used in silicon rectifiers to shorten the life of the injected minority carriers, thereby shortening the recovery time.
In order to reduce the possibility of damage to the rectifier caused by overvoltage breakdown and improve the reliability of the rectifier, a silicon avalanche rectifier can be used. In this device, when the reverse voltage exceeds the allowable peak value, the entire PN junction may even undergo avalanche breakdown. The device can work under high voltage and high current conditions, and can withstand considerable reverse surge power. When making such devices, it is required to have few material defects, uniform resistivity, smooth junction surface, and proper protection of the exposed junction area to avoid surface breakdown. The selenium rectifier has large anti-overload capability and strong anti-surge power capability.