Technique for reducing rectifier reverse-recovery-related losses in high-voltage high power converters
First Claim
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1. A power converter for driving an output load, comprising:
- an input voltage source;
an output filter capacitor coupled in parallel with said output load;
a first inductor provided for storing energy from said input voltage source;
a rectifier;
a primary switch controlled by a first control signal, said primary switch coupling said energy from said input voltage source to said first inductor, when said primary switch is closed; and
an active snubber, including a second inductor, a clamping capacitor and an auxiliary switch controlled by a second control signal, wherein when said auxiliary switch is closed, said second inductor and said clamping capacitor are coupled in series, and wherein when said primary switch is closed, said second inductor controls a rate of change of current in said rectifier and, when said primary switch is open, energy in said second input is transferred through said clamping capacitor to a reference voltage source, said first and second control signals closing said primary and auxiliary switches at mutually exclusive time intervals.
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Abstract
A circuit technique that substantially reduces the boost-converter losses caused by the reverse-recovery characteristics of the rectifier is described. The losses are reduced by inserting an inductor in the series path of the boost switch and the rectifier to control the di/dt rate of the rectifier during its turn-off. The energy from the inductor after the boost switch turn-off is returned to the input or delivered to the output via an active snubber. The same technique can be extended to any member of the PWM-converter family.
201 Citations
16 Claims
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1. A power converter for driving an output load, comprising:
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an input voltage source; an output filter capacitor coupled in parallel with said output load; a first inductor provided for storing energy from said input voltage source; a rectifier; a primary switch controlled by a first control signal, said primary switch coupling said energy from said input voltage source to said first inductor, when said primary switch is closed; and an active snubber, including a second inductor, a clamping capacitor and an auxiliary switch controlled by a second control signal, wherein when said auxiliary switch is closed, said second inductor and said clamping capacitor are coupled in series, and wherein when said primary switch is closed, said second inductor controls a rate of change of current in said rectifier and, when said primary switch is open, energy in said second input is transferred through said clamping capacitor to a reference voltage source, said first and second control signals closing said primary and auxiliary switches at mutually exclusive time intervals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification