A simple slip-power recovery system with a DC voltage intermediate circuitand reduced harmonics on the mains

A different circuit configuration for the slip-power recovery system is pre sented in this paper. A boost chopper is used to connect the diode rectifie r to the de-link voltage, which is composed of a capacitor and a voltage-so urce inverter (VSI), The diode rectifier gives rise to mains current harmon ics of variable frequency, which can present subharmonics, harmonics, and i nterharmonics that can lead to nicker in the mains. Two simple solutions to this drawback are studied. In the first solution, additional inductances w ere connected on the ac side of the rotor circuits to increase the overlap angle. In the second solution, the stator current harmonics are compensated by a VSI that can work simultaneously as an inverter and as an active powe r filter. This system represents a very interesting and useful application for active power filters, The merits of the configuration presented are cos t, control simplicity, the possibility of reactive power control over a wid e range, and quasi-optimum exploitation of the electrical machine. The char acteristics of the proposed system and its control are presented in this pa per. It is concluded that, although the system proposed is much simpler tha n others, it has interesting performance.