| 摘要 |
Methods and apparatus are disclosed for suppressing or eliminating nonlinear current drawing characteristics, while at the same time substantially eliminating high order current harmonics. In accordance with various aspects of the present invention, an energy transfer system, for example a pulse width modulator (PWM) flyback converter (22), comprises an inductor (L) interposed between the AC line voltage and the load (Rload), with a controllable switch (26) provided between the inductor (L) and the negative supply leg of a rectifier circuit (10). The duty cycle of the converter switch (26) is suitably controlled to produce a substantially constant DC output from the converter (22). Proper synchronization of the converter switch (26) ensures that the current through the inductor (L) and the output current through the load (Rload) remains in phase with the AC supply voltage. Thus, a power factor on the order of unity is maintained while substantially eliminating nonlinear current drawing characteristics.
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