In this paper, two passive solutions for noise reduction of PWM-fed induction machines are compared: the use of LC filter connected between the PWM inverter and the machine, and a three-phase damper wound inside the machine and connected to three capacitors. Firstly, the principle, advantages and disadvantages of each solution are recalled. The equivalent electrical circuits used for the study are also explained. Then, the effectiveness of both solutions in terms of voltage harmonic reduction and harmonic flux density reduction is discussed. The weight and size criteria are also studied. Results are given for two different power ranges of induction machines: 4 kW and 55 kW, and for two different switching frequencies of the PWM inverter: 3 kHz and 8 kHz.
Three-Phase Trinary Asymmetric Multilevel Inverter With Single DC Source and Open-Loop Control
