On influence of deterministic and non-deterministic modulation schemes in two-level filter-less inverter performance driving a permanent magnet synchronous motor

A drive train system (DTS) powered by a battery and driving a permanent magnet synchronous motor (PMSM) is discussed in this paper. A two-level, three-phase conventional inverter with no harmonic filters on both AC and DC sides is used as means of power conditioning. This DTS is modeled as a double oscillator according to the mechanical part in an electric vehicle. Two inverter modulation schemes are applied, namely, a hysteresis scheme (non-deterministic) and one based on sinusoidal-triangular waveforms (deterministic). The influence of these modulation schemes on the performance of the DTS is determined by assessing the level of inverter generated harmonics flowing from/to the battery (electrical part) and the motor (mechanical part). The simulated results presented in the paper indicate that the absence of filters can be partly retained by a dispersion of the harmonic energy of the inverter generated spectral due to high frequency switching. This can be achieved by using a hysteresis control scheme and the impact of the filter-less inverter on the DTS performance is limited only by process specifications.