Harmonics and Efficiency Associated with Electric Vehicles

Nowadays, electric cars are one of the cures for climate change and for the depletion of natural resources. The charger of car batteries distorts the shape of the voltage supply. Effective suppression of emanating from the converter harmonics requires the use of multi-link complex filters. But some of the harmonics remain unsuppressed. The electromechanical decoupling in the form of a synchronous machine between the electric car park charger and the network under certain conditions effectively absorbs all harmonics. On the other hand, to power the vehicle motor, an electric inverter outputs ac voltage that contains a good portion of harmonics. These harmonics degrade the efficiency of the motor. To improve the shape of the ac curve at the output of the inverter, the switching device of the inverter must supply pulses of specific amplitude and location within the half-cycle of the output voltage or pulses of the same amplitude and specific location. The last has a slightly worse efficiency, but requires the same input voltage level. Summarizing the above, the suppression of harmonics coming from the converter and increasing the efficiency of the inverter are considered.