Determination of the possibility of ac voltage stabilization using a pulsed polarity-inverting converter. Part 1

Resumo

Details are investigated of the operation of an ac voltage stabilizer, a polarity-inverting pulsed converter, in the absence of input-voltage waveform distortions. The stabilizer performance was determined on the basis of a limit continuous model thereof corresponding to a vanishingly small switching period. It has been found that, in the steady-state harmonic mode, the inverting pulsed converter can be considered as an adjustable voltage source with output resistance proportional to the choke impedance. The possibility is shown of stabilizing the output voltage when the input voltage varies in a wide range without its preliminary biasing. To meet practical requirements for smoothness of output-voltage high-frequency pulsations expression have been obtained for calculating the choke inductance and condenser capacity taking into account the admissible range of choke current and output-voltage pulsations at a selected switching frequency. A technique of voltage stabilization is investigated that is based on control of the perturbation impact by way of regulating the relative time that the key stays in extreme positions, which depends on the ratio between the actual and preset voltage amplitudes. Unlike in the case of control based on deviation (a closed-loop contour), in this case ensuring stability is not a problem because the cause of the change of output voltage is dealt with rather than the consequence. It is established that, at sufficiently high structure switching frequency, control by perturbation provides sufficient accuracy of voltage stabilization because of low choke resistance.