How to correctly determine the advantages and disadvantages of communication switching power supply
Power Devices
Products roughly the development of the age. We know that high-power silicon rectifier and thyristor appeared in the 1960s; high-power inverter thyristor, giant power transistor (GTR) and gate turn-off thyristor (GTO) production in the 1970s; power field effect tubes (MOSFETs) appeared in the 1980s; insulated gate bipolar transistor (IGBT) is a device that appeared in the 1990s. The device in the 1990s. It should be noted that the power field effect tube due to unipolar polysub conductivity, significantly reducing the switching time, so it is easy to achieve a switching frequency of 1MHz. However, the power field effect tube to improve the device blocking voltage must be widened device drift region, the result is that the device internal resistance increases rapidly, the device's pass-state voltage drop increases, the pass-state loss increases. Insulated gate bipolar transistor in the structure similar to the power field effect tube, the difference is that the insulated gate bipolar transistor is in the N-channel power field effect tube N + substrate (drain) on the addition of a P + substrate (insulated gate bipolar transistor collector), this point of improvement makes the insulated gate bipolar transistor has a series of outstanding advantages: forward bias, high input impedance, low on-resistance. High withstand voltage, large safe working area and high switching speed.
Looking at the power device package can also be a simple way to identify the advantages and disadvantages of the communication power supply. The tube core is directly soldered to the substrate, which can improve the heat dissipation efficiency and reduce the parasitic inductance, capacitance and thermal resistance. Not directly welded to the substrate of the product, it is worse.
Communication switching power supply technology belongs to the power electronics technology, which uses the power converter for power conversion, and thus it is easy to deduce from the type of power device
Circuit principle
1. To see whether it uses hard switching technology or soft switching technology. Various kinds of consumption-free buffer circuits composed of LC passive components and fast recovery diodes change the Switching tube switching transition process, so that the switching voltage, current change is not abrupt (i.e., hard switching) but slow change (i.e., soft switching), thus significantly reducing the power device switching losses, increase the switching frequency of the system, reduce the size and weight of the converter, reduce the output ripple of the system, and can overcome the change of Switching circuit sensitivity to parasitic distribution parameters, reduce the switching noise of the system, broaden the frequency band of the system, improve the dynamic performance of the system.
2. Depends on whether it uses frequency control (PFM) or constant frequency control (PWM). Constant frequency control (also known as phase shift control) is superior to frequency control The constant frequency control (also known as phase shift control) method is superior to the inverter control method. The phase shift control full-bridge converter circuit integrates the advantages of constant frequency control technology and soft switching technology to achieve constant frequency control over a wide range and stepless adjustment of output voltage or current over a wide range. or current stepless adjustment in a wide range, and realise zero-voltage switching current conversion at the instant of power device current conversion.
3. The power factor correction technology can inhibit the harmonic current on the grid side and reduce the reactive power, so as to improve the power factor, and at the same time reduce the noise and pollution produced by the high harmonics of the power supply, so as to achieve energy saving. At the same time, it reduces the noise and pollution generated by the high harmonics of power supply and achieves the purpose of energy saving.
4. Load current equalisation is a key technology, which makes the output imbalance of the module and machine reduce, and makes the system redundant and fault-tolerant, which is easy to form a large-capacity communication power system. Into a large-capacity communication power supply system. At present, there are mainly droop (droop) equalisation method, master-slave set master-slave equalisation method, average current average current method, and average current equalisation method. Current average current average current method, external controller external controller average current method, maximum The maximum current is automatically the highest current method. The maximum current automatic equalisation method can achieve both the automatic equalisation of the power module and the Power module redundancy, power module exit and increase do not affect the normal work of the system, equalisation bus open circuit, short circuit and module damage will not affect the normal work of other modules of the system. The open or short circuit of the equalisation bus and the damage of the module will not affect the normal work of other modules of the system.
