Emission testing for the EMC performance evaluation of an electric wheelchair

This paper deals with emission testing of an electrically powered wheelchair with the purpose of a complete and accurate EMC (electromagnetic compatibility) performance evaluation of such a vehicle from different points of view. An extensive experimental test campaign has been carried out in a semi-anechoic chamber with two aims: to assess the influence and the interactions between the main subcomponents of the wheelchair PDS (power drive system) - such as power electronics, driving circuit and control circuit - and to compare emissions related to different typologies of PWM (pulse width modulation) modulation techniques, both deterministic and random, implemented in the inverters feeding the two twin AFPM (axial flux permanent magnet) wheel-motors the under test wheelchair is equipped with. Besides, an investigation of alternative test procedures has been accomplished to estimate the wheelchair EMC performance even during normal modes of operation (i.e. start-up, acceleration, turning, deceleration and braking)