There are many non-components in the high-power DC power supply, among which several common components such as amplifier, pulse width modulator, oscillator and so on play a very key role in the stability and reliability of the power supply. Then let's talk about the role of these three important components in the DC adjustable power supply:

 

1000kw load bank
 

1. Amplifier

The gain of the error amplifier is set by the dynamic impedance Zc of the control end. Zc varies from 10 to 20 ω, with a typical value of 15 ω. After comparing the feedback voltage UF with 5.7V reference voltage, the error amplifier outputs error current Ir and forms error voltage UR on RE.

2. Pulse width modulator (PWM)

Pulse width modulator is a voltage feedback control circuit, which has two meanings. First, by changing the size of the current Ic at the control end, duty cycle D can be adjusted to achieve pulse width modulation. Second, the error voltage UR constitutes a low pass filter with a cut-off frequency of 7kHz through RA and CA. After filtering the switching noise voltage, it is added to the in-phase input end of THE PWM comparator and then compared with the sawtooth wave voltage UJ to generate a pulse width modulation signal UB.

3. The oscillator

The internal oscillating capacitors charge and discharge linearly periodically between the set upper and lower thresholds UH and UL to generate the sawtooth wave (SAW) required by the pulse width modulator, as well as the maximum duty cycle signal (Dmax) and CLOCK signal (CLOCK). In order to reduce electromagnetic interference and improve the efficiency of high-power DC power supply, the oscillation frequency (i.e. switching frequency) is designed as 100kHz.