US 5,734,258 AGranted

Bidirectional buck boost converter

AssigneeGeneral Electric Company

InventorAlbert Andreas Maria Esser

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Abstract

A bidirectional buck boost converter and method of operating the same allows regulation of power flow between first and second voltage sources in which the voltage level at each source is subject to change and power flow is independent of relative voltage levels. In one embodiment, the converter is designed for hard switching while another embodiment implements soft switching of the switching devices. In both embodiments, first and second switching devices are serially coupled between a relatively positive terminal and a relatively negative terminal of a first voltage source with third and fourth switching devices serially coupled between a relatively positive terminal and a relatively negative terminal of a second voltage source. A free-wheeling diode is coupled, respectively, in parallel opposition with respective ones of the switching devices. An inductor is coupled between a junction of the first and second switching devices and a junction of the third and fourth switching devices. Gating pulses supplied by a gating circuit selectively enable operation of the switching devices for transferring power between the voltage sources. In the second embodiment, each switching device is shunted by a capacitor and the switching devices are operated when voltage across the device is substantially zero.

Claims19

Dependent claims

A bidirectional buck boost converter for regulating power flow between first and second voltage sources in which each source voltage level is subject to change and power flow is independent of relative voltage levels, each of the voltage sources having a positive terminal and a negative terminal, the converter comprising:

first and second switching devices serially coupled between the positive and negative terminals of the first voltage source;
third and fourth switching devices serially coupled between the positive and negative terminals of the second voltage source;
first and second diodes coupled in parallel with said first and second switching devices, respectively, and poled to conduct current from said negative terminal of said first voltage source to said positive terminal of said first voltage source;
third and fourth diodes coupled in parallel with said third and fourth switching devices, respectively, and poled to conduct current from said negative terminal of said second voltage source to said positive terminal of said second voltage source;
an inductor coupled between a junction intermediate said first and second switching devices and a junction intermediate said third and fourth switching devices;
conductive means coupling one of said terminals of one polarity of said first voltage source to one of said terminals of said one polarity of said second voltage source;
and
gating means for enabling operation of each of said switching devices for transferring power between said voltage sources.

5 more elements

Dependencies are inferred from the claim text.