Seamless Fault-Tolerant Operation of Two-Transformer Full-Bridge Resonant PWM Converter With Built-In Circuit Redundancy

초록

Conventional full-bridge resonant pulsewidth-modulated (PWM) DC/DC converter employing two transformers can be used for 48-V level low-voltage DC/DC converter applications. However, when one of the secondary-side legs suffers from open/short circuit problems, the semiconductor devices can be destroyed by short-circuit current or the transformer can be saturated. To overcome this problem, this article proposes a reconfigurable resonant PWM full-bridge converter that has two split capacitors and one bidirectional switch. The main feature of this converter is that it can transfer the half of the rated power seamlessly under open/short circuit problems without using the extra feedforward control duty while not affecting the output voltage. Also, this power transfer does not exceed the predetermined rated power of either of transformers. This trait enables the use of compact-size transformers without having transformer saturation problem. A 1-kW rated prototype that converts 400-V input to 52-V output is designed and tested to validate the concept of reliable operation.

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