METHODS AND APPARATUS FOR EMI FILTER HAVING SWITCHED CAPACITANCE BASED ON LOADING

摘要

Methods and apparatus for providing a system, such as a power conditioner unit, including terminals to receive three-phase signals, respective filter inductors, and respective filter capacitors that are switched into the EMI filter when the loading is above a given threshold.

主权项

1. A system, comprising:
a first terminal to receive a first phase signal of a three-phase signal; a second terminal to receive a second phase signal of the three-phase signal; a third terminal to receive a third phase signal of the three-phase signal; a first filter inductor to filter the first phase signal; a second filter inductor to filter the second phase signal; a third filter inductor to filter the third phase signal; and a switch control module, comprising:
a signal detection module coupled to the filtered first phase signal;a processor module coupled to the signal detection module to determine if the filtered first phase signal exceeds a first threshold;a driver circuit coupled to the processor module;a first switch coupled to a first filter capacitor and to the driver circuit;a second switch coupled to a second filter capacitor and to the driver circuit; anda third switch coupled to a third filter capacitor and to the driver circuit, wherein the processor module activates the driver circuit to actuate the first, second, and third switches when the first threshold is exceeded for coupling the first, second, and third filter capacitors into the EMI filter.