MODULATION METHOD FOR THE BOOST CONVERTER OPERATING MODE OF A PUSH-PULL CONVERTER

摘要

The invention relates to a method for modulating the boost converter operating mode of a push-pull converter having a low-voltage-side circuit, having a first low-voltage-side switching device and a second low-voltage-side switching device; having a transformer having a high-voltage-side winding; and having a high-voltage-side circuit, which is configured as a full-bridge rectifier, having a first and a second rectification element which form a first half-bridge and a third and a fourth rectification element which form a second half-bridge; wherein the method comprises the steps of closing the first low-voltage-side switching device whilst simultaneously short-circuiting the high-voltage-side winding via the first or the fourth rectification element during a first time segment; opening the rectification element used for short-circuiting the high-voltage-side winding during a second time segment; opening the first low-voltage-side switching device and closing the second low-voltage-side switching device whilst simultaneously short-circuiting the high-voltage-side winding via the third or the fourth rectification element in the second half-bridge during a third time segment; and opening the rectification element used for short-circuiting the high-voltage-side winding during a fourth time segment.

主权项

1. Method for modulating the boost converter operating mode of a push-pull converter (10) having:
a low-voltage-side circuit (29), which is designed to convert a DC voltage (5) applied to the low-voltage side into a low-voltage-side AC voltage, having a first low-voltage-side switching device (25a), a second low-voltage-side switching device (26a) and a throttle (4); a transformer (2) having a low-voltage-side winding and high-side voltage winding, said transformer being designed to receive the low-voltage-side AC voltage at the low-voltage-side winding and to generate a high-voltage-side AC voltage at the high-voltage-side winding; and a high-voltage-side circuit (20), which is configured as a full-bridge rectifier in order to convert the high-voltage-side AC voltage into a high-voltage-side DC voltage (1), having a first (21) and a second rectification element (22), which form a first half bridge, and a third (23) and a fourth rectification element (24), which form a second half-bridge; wherein at least the first (21) or the fourth rectification element (24) is designed as a switching device and wherein at least the second (22) or the third rectification element (23) is designed as a switching device; wherein the method comprises the following steps:
closing the first low-voltage-side switching device (25a) in order to generate a first voltage at the transformer (2) and in order to feed energy into the transformer (2) and the throttle (4) whilst simultaneously short-circuiting the high-voltage-side winding via the first (21) or the fourth rectification element (24) during a first time segment ([0,t1]) of a modulation cycle;opening the rectification element (21, 24) used for short-circuiting the high-voltage-side winding in order to generate a high-voltage-side DC voltage (1) during a second time segment ([t1,t2]) of the modulation cycle;opening the first low-voltage-side switching device (25a) and closing the second low-voltage-side switching device (26a) in order to generate a second voltage at the transformer (2), which has a polarity opposite to the first voltage, whilst simultaneously short-circuiting the high-voltage-side winding via the second (22) and the third rectification element (23) of the second half-bridge during a third time segment ([t2,t3]) of the modulation cycle; andopening the rectification element (22, 23) used for short-circuiting the high-voltage-side winding in order to generate a high-voltage-side DC voltage (1) during a fourth time segment ([t3,t4]) of the modulation cycle.