Wednesday, December 29, 2010

【 Weak current College 】 high frequency switching power supply system main specifications 】

High-frequency switching power supply rated DC output voltage, the floating charge voltage, equalizing charge voltage, power, voltage accuracy, efficiency, noise voltage (no batteries), battery temperature compensation, etc.
1, rated DC output voltage: 220V 50 Hz through rectifier module transformed rated output voltage, primary power voltage-48V, changes in the range of voltage allows —-57V-40. This kind of "-"-base voltage is the power supply being fed wire GND, reference potential zero Volt, negative feed line binding after receiving fuses and rack power supply connection.

2, the floating charge voltage: 220V 50 Hz normal battery and rectifier in parallel operation, battery self-discharge capacity loss caused in the float process is complete. According to battery characteristics and temperature required to add the number of current loss of voltage.

3, equalizing charge voltage: in order to make the battery quickly added capacity, depending on the need to increase floating charge voltage, the electric current flows to the battery supplement increases, this process have voltage of the rectifier output as "equalizing charge voltage".

4, power factor: active power contact in the power of the ratio is called the power factor. Due to the switching power supply circuit commutation section allows the grid current waveform distortion, harmonic content, which makes the power factor reduction (not adopted any measures, the power factor only 0.6 ~ 0.7), polluted the grid environment. Switching power supply to large quantities into the power grid, it is necessary to improve the power factor, and reduce pollution of the power grid, so as not to undermine the quality of the electricity grid. Fully loaded state, the power factor 0.92.

5. efficiency: high frequency switch power supply module of life is determined by the internal working temperature module. Temperature rise of main low mainly by module efficiency. Now on the market, extensiveuse of switching power supply technology, major mining has a pulse width modulation (PWM). Module of loss mainly by switching valve open, turn off and on-three state loss, surge absorbing circuit loss, rectifier diode conduction losses, and auxiliary power consumption and core components constitutes a loss and other factors. Reducing these losses will improve the overall efficiency of the module. On the existing good treatment methods are: switching valve open, turn off and on-State of loss using MOSFET and IGBT parallel use, using two different types of devices and conduction losses at the beginning of the synergy of its comprehensive loss is the use of a single type switch tube work loss by 20%; surge absorbing circuit can be lossless snubber, the use of this technology allows significant reduction in the part of the loss; rectifier diode can be used on-resistance of smaller devices, optimization of control circuit, select integrated high IC devices can reduce power consumption; core material can select such as Philip of 3C90 can be reduce loss. High frequency capacitor choice strictly control peak current size, use of these factors will enable the rectifier module work in quite a wide range of output power to maintain a high efficiency, such as VMA10, DMA12, DMA13 and DMA14 productivity are 91 percent. It is the opening of the main switching valve, shut-off and on-State the proportion of the loss is the key. Switch status of loss is a PWM control technology the inherent disadvantages. Fully loaded state, the efficiency is not lower than 0.90.

6 voltage accuracy: loaded condition, when the input voltage from maximum to minimum, Rectifier output voltage adjustment range of not more than ± 1%.

7. noise voltage (no batteries)

① weighted noise: telephone circuits to 800HZ noise voltage standard, other frequency noise voltage loudness intensity, using equivalent noise coefficient expressed as weighted noise.

System counter weight noise measurement sightsee site of choice in rectifier output, battery output and input of the machine room rack, the numerical measurement point.

② broadband noise: it refers to the harmonic mean-square value — the cycle of continuous spectrum voltage.

③ peak noise: superimposed on the DC output peak AC component on the thyristor or high-frequency switching circuit caused by needle-like pulses.

④ discrete noise: refers to radio interference noise or RF noise, typically within individual 150kHz-30MHz frequency frequency noise.

⑤ peak-peak noise: only because of a power interruption or native failures caused by noise.

Indicators are as follows:

Phone weighted noise voltage ≤ 2mV (3m ~ 3400Hz).

Broadband noise voltage ≤ 100mV (3.4 ~ 150kHz).

Broadband noise voltage ≤ 30mV (0.15 ~ 30MHz).

Discrete frequency noise voltage ≤ 5mV (3.4 ~ 150kHz).

Discrete frequency noise voltage ≤ 3mV (150 ~ 200kHz).

Discrete frequency noise voltage ≤ 2mV (200 ~ 500kHz).

Discrete frequency noise voltage ≤ lmV (0.5 ~ 30MHz).

Peak-peak noise voltage ≤ 200mV.

8. the battery temperature compensation: for valve control battery temperature compensation automatically adjust function, when the ambient temperature at every rising or lowering the once DC output voltage 3mv should be adjusted or elevated 3mv.

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