| CPC H02M 1/0009 (2021.05) [H02M 1/4241 (2013.01)] | 10 Claims |
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1. A current sampling circuit for a bridgeless power factor corrector, being connected to the bridgeless power factor corrector, wherein the bridgeless power factor corrector is electrically connected to an AC power and has a first fast switch and a second fast switch; an energy storage current flows through the second fast switch in a positive half cycle of the AC power and flows through the first fast switch in a negative half cycle of the AC power; the current sampling circuit comprising:
a sampling resistor;
a first current sampling module, comprising:
a first transformer, comprising a first primary winding and a first secondary winding, wherein the first primary winding and the first secondary winding are coupled with each other; the first primary winding and the first fast switch are connected in series;
a first sampled current phase switching unit, wherein the first secondary winding is connected to the sampling resistor through the first sampled current phase switching unit; and
a first main current freewheeling unit, connected to the first secondary winding in parallel;
a second current sampling module, comprising:
a second transformer, comprising a second primary winding and a second secondary winding, wherein the second primary winding and the second secondary winding are coupled with each other; the second primary winding and the second fast switch are connected in series;
a second sampled current phase switching unit, wherein the second secondary winding is connected to the sampling resistor through the second sampled current phase switching unit; and
a second main current freewheeling unit, connected to the second secondary winding in parallel; wherein
in the positive half cycle of the AC power, the second sampled current phase switching unit between the second secondary winding and the sampling resistor is turned on to form a second sampling circuit, and the first main current freewheeling unit is turned on between two ends of the first secondary winding;
in the negative half cycle of the AC power, the first sampled current phase switching unit between the first secondary winding and the sampling resistor is turned on to form a first sampling circuit, and the second main current freewheeling unit is turned on between two ends of the second secondary winding.
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