US 3,944,907 A · Zero deadband four-quadrant full-wave converter

Abstract

A four-quadrant full-wave static converter having improved time response without current cross-over deadband. An alternating current wave is imposed on the direct current input signal, which generates gate pulses for appropriate thyristors at the desired firing angle. The applied alternating current signal can be of approximately the same magnitude as the converter deadband, so as the direct current signal varies from zero a portion of the control signal moves out of the deadband area. For fast response the magnitude of the alternating current signal can be greater than the deadband signal. As the magnitude of the direct current signal increases the relative magnitude of the alternating current signal is decreased, preventing a large DC component from being imposed on the supply during high current operations. Cycling of the imposed alternating current waves is synchronized with the firing angle point O to maintain system protection.

Claims19

Dependent claims

An improved four-quadrant converter comprising:

four-quadrant full-wave static converter means for transferring power between a direct current load and an alternating current supply comprising a first plurality of triggerable devices which when triggered permit positive current flow and a second plurality of triggerable devices which when triggered permit negative current flow;
firing angle selecting means connected to said four-quadrant full-wave static converter means for selecting the firing angle and the appropriate polarity triggerable devices in accordance with the magnitude and polarity of a direct current input signal;
and
alternating current signal means connected to said firing angle selecting means for imposing an alternating current signal, whose frequency is a function of line frequency and whose phase position is selected so polarity changes occur in proximity to a firing angle zero, on the direct current input signal.

1 more element

A fast-response four-quadrant converter for transferring power between direct current apparatus and an alternating current system comprising:

a first plurality of triggerable devices connected between the direct current apparatus and the alternating current system for permitting positive current flow when triggered;
a second plurality of triggerable devices connected between the direct current apparatus and the alternating current system for permitting negative current flow when triggered;
gate driver means for triggering said first plurality of triggerable devices or said second plurality of triggerable devices in response to the polarity and magnitude of an input signal where the polarity of the input signal determines which of said first plurality of triggerable devices or said second plurality of triggerable devices can be triggered and the magnitude of the input signal determines the firing angle at which the selected triggerable devices are triggered;
input signal supply means connected to said gate driver means for applying an input signal which has an AC component and a DC component;
and
said gate driver means does not trigger said first plurality of triggerable devices until the magnitude of the input signal exceeds a first deadband level and does not trigger said second plurality of triggerable devices until the magnitude of the input signal exceeds a second deadband level.

3 more elements

Dependencies are inferred from the claim text.

Zero deadband four-quadrant full-wave converter

Life of this patent

Zero deadband four-quadrant full-wave converter

Life of this patent

Abstract

Claims19