Influence of the switching frequency of the switch and the amplitude of the reference voltage of a pulsed voltage regulator of the lowering type on its stability

Abstract

On the basis of classical stability criteria, using the expressions of the transfer function, according to the block diagram, the stability of the impulse controller with feedback is estimated. The influence of the switching frequency of the switch and the amplitude of the reference voltage on the stability of a pulsed voltage regulator of a lowering type with deterministic parameters of the system is analyzed. In accordance with the Nyquist criterion for the transfer function of an open-loop system, both stability and phase stability margins for a closed-loop system can be estimated. When simulating the operation of the device, the phase stability margin was obtained, according to the Nyquist criterion, which is γс = Н = 7°. An increase in the sawtooth voltage is not a desirable phenomenon, which, although it increases the margin of stability, however, reduces stability. Moreover, the dependence of the ripple, affecting the stability of operation, on the amplitude of the sawtooth voltage is not a predictable value and takes on a random value

Keywords

• switching voltage regulator
• stability margin
• logarithmic frequency characteristics
• pulse-width modulation