| 摘要 |
An active EMI filter having a rectifier coupled to an AC network, the rectifier supplying DC power to a DC bus, and the DC bus feeding an inverter stage for providing AC power to a load. The load having a ground return line (GND) to a ground connection of the AC network. The active filter having a transistor switching stage (Q1, Q2) coupled across the DC bus. A current sensor (G1, G2) coupled to the DC bus for sensing the common mode current flowing in the DC bus, and the current sensor (G1, G2) having inputs coupled to respective legs of the DC bus and an output driving the transistor switching stage (Q1, Q2). A capacitor coupling the transistor switching stage (Q1, Q2) and the ground return line (GND). The capacitor providing a cancellation current to the ground return line (GND) from the transistor switching stage (Q1, Q2) to substantially cancel the common mode current in the ground return line (GND).
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