Discussion on the main technical parameters of high frequency switching power supply system

5. Efficiency: The life of the high-frequency switching power supply module is determined by the internal working temperature rise of the module. The temperature rise is mainly determined by the efficiency of the module. The switching power supply technology currently used in the market is mainly pulse width modulation technology (PWM). The module loss is mainly composed of the loss of the switch tube in the three states of opening, closing and conducting, the surge absorption circuit loss, the rectifier diode conduction loss, the power consumption of the auxiliary power supply and the core component loss. Reducing these losses will improve the overall efficiency of the module. The current better treatment methods are: the loss of the switch tube in the opening, closing and conducting states is used in parallel with MOSFET and IGBT, and the advantages of the opening and conduction losses of two different types of devices are complementary. The comprehensive loss is about 20% of the working loss of a single type of switch tube; the surge absorption circuit can use a lossless absorption circuit. The use of this technology has greatly reduced the loss of this part; the rectifier diode can use a device with a smaller on-resistance, optimize the design of the control circuit, and select IC devices with a higher degree of integration to reduce power consumption; the core material can be selected such as Philips' 3C90 to reduce the loss. The selection of high-frequency capacitors strictly controls the size of the peak current. The use of these factors will enable the rectifier module to maintain a high efficiency in a fairly wide power output range. For example, the working efficiency of VMA10, DMA12, DMA13 and DMA14 is above 91%. It should be noted that the loss of the main switch tube in the on, off and on states accounts for the main proportion. The loss in the switching state is an inherent disadvantage of PWM control technology. Under full load, the efficiency is not less than 0.90. String 3

6. Voltage regulation accuracy: Under full load, when the input voltage changes from maximum to minimum, the rectifier output voltage adjustment range does not exceed ±1%. String 2

[page] 7. Noise voltage (not connected to battery pack)

① Counterweight noise: The telephone circuit uses 800HZ noise voltage as the standard, and the loudness of other frequency noise voltages is expressed by an equivalent noise coefficient, which is called counterweight noise.

The measurement points of the system weighing noise are selected at the rectifier output end, battery output end and input end of the machine room rack according to the situation, and the values ​​of each measurement point are different.

② Broadband noise: It refers to the root mean square value of each harmonic, that is, the periodic continuous spectrum voltage.

③ Peak noise: refers to the peak value of the AC component superimposed on the DC output, that is, the needle-shaped pulse caused by the thyristor or high-frequency switching circuit. ④ Discrete noise: refers to radio interference noise or radio frequency noise, usually individual frequency noise within the frequency range of 150kHz-30MHz.

⑤ Peak-to-peak noise: Noise generated only by power supply interference or machine failure.
The indicators are as follows: