Flying Capacitor Multilevel Inverter Reduces Harmonic Loss in High-Speed Motor Drive Systems

When inverters drive an AC motor, the harmonic components of the output voltage caused additional iron and copper losses in the magnetic cores of the motor. Since inductance is supposed to be small in high-speed motors, the ripple in the current flowing through the motor increases. Therefore, in high-speed motors, ripple current losses often result in significant additional losses. As a solution to these problems, multilevel inverters are used in high-speed motor drive systems in this study. The internal voltage sources of multilevel converters can produce a wide range of output voltages. As a result, harmonics and EMI are reduced. The simulated and experimental results show that multilevel inverters can reduce motor losses in high-speed motors.