80026-044-06-R PLC开关电源模块

80026-044-06-R PLC开关电源模块

电源开关里有一扇门，一开门电源就通过，一关门电源就停止通过，那么什么是门呢，开关电源里有的采用可控硅，有的采用开关管，这两个元器件性能差不多，都是靠基极、(开关管）控制极(可控硅)上加上脉冲信号来完成导通和截止的，脉冲信号正半周到来，控制极上电压升高，开关管或可控硅就导通，由220整流、滤波后输出的30O电压就导通，通过开关变压器传到次级，再通过变压比将电压升高或降低，供各个电路工作。振荡脉冲负半周到来，电源调整管的基极、或可控硅的控制极电压低于原来的设置电压，电源调整管截止，300电源被关断，开关变压器次级没电压，这时各电路所需的工作电压，就靠次级本路整流后的滤波电容放电来维持。

待到下一个脉冲的周期正半周信号到来时，重复上一个过程。这个开关变压器就叫高频变压器，因为他的工作频率50hz低频。那么推动开关管或可控哇的脉冲如何获得呢，这就需要有个振荡电路产生，我们知道，晶体三极管有个特性，就是基极对发射极电压是0.65-0.7v是放大状态，0.7以上就是饱和导通状态，-0.1v--0.3就工作在振荡状态，那么其工作点调好后，就靠较深的负反馈来产生负压，使振荡管起振，振荡管的频率由基极上的电容充放电的时间长短来决定，振荡频率高输出脉冲幅度就大，反之就小，这就决定了电源调整管的输出电压的大小。

那么变压器次级输出的工作电压如何稳压呢，一般是在开关变压器上，单绕一组线圈，在其上端获得的电压经过整流滤波后，作为基准电压，然后通过光电耦合器，将这个基准电压返回振荡管的基极，来调整震荡频率的高低，如果变压器次级电压升高，本取样线圈输出的电压也升高，通过光电耦合器获得的正反馈电压也升高，这个电压加到振荡管基极上，就使振荡频率降低，起到了稳定次级输出电压的稳定

80026-044-06-R PLC开关电源模块

There is a door in the power switch, the power supply passes through the door, the power supply stops passing through the door, then what is the door, some use thyristor in the switching power supply, some use the switching tube, the performance of these two components is similar, are based on the base, (switching tube) control pole (thyristor) plus pulse signal to complete the conduction and cut-off, the pulse signal is half week to come, The voltage on the control pole rises, the switching tube or thyristor is switched on, the 30O voltage output after 220 rectification and filtering is switched on, transmitted to the secondary through the switching transformer, and then the voltage is increased or decreased by the transformer ratio for each circuit to work. The oscillating pulse is negative for half a week, the base of the power adjustment tube, or the control pole voltage of the thyristor is lower than the original setting voltage, the power adjustment tube is cut off, the 300 power supply is turned off, the switching transformer has no secondary voltage, and the working voltage required by each circuit is maintained by the filter capacitor discharge after the secondary rectifier.

Repeat the previous process until the next pulse's periodic positive half-cycle signal arrives. This switching transformer is called a high-frequency transformer, because its working frequency is 50hz low frequency. So how to promote the switching tube or controlled wow pulse, which requires an oscillation circuit, we know that the transistor has a characteristic, that is, the base to the emitter voltage is 0.65-0.7v is the amplification state, 0.7 is above the saturation conduction state, -0.1v--0.3 is working in the oscillation state, then its operating point is adjusted, Rely on the deeper negative feedback to generate negative pressure, so that the oscillation tube vibration, the frequency of the oscillation tube by the capacitor on the base of the charge and discharge time to determine the oscillation frequency of the high output pulse amplitude is large, and vice versa is small, which determines the size of the output voltage of the power adjustment tube.

Then the transformer secondary output working voltage how to regulate it, generally on the switching transformer, a single coil, the voltage obtained at the upper end of the rectifier filter, as a reference voltage, and then through the photoelectric coupler, the reference voltage back to the base of the oscillation tube, to adjust the oscillation frequency, if the transformer secondary voltage rises, The output voltage of the sampling coil also increases, and the positive feedback voltage obtained through the photoelectric coupler also increases. When this voltage is added to the base of the oscillating tube, the oscillation frequency is reduced, and the stable secondary output voltage is stabilized