Analysis of real-time energy losses of electric vehicle caused by non-stationary road irregularity

Abstract

To enhance the road mobility of EVs, this research performs the accurate modeling of non-stationary road irregularity and estimates the real-time power consumption of shock absorbers and the energy slip loss of the driving wheel. First, a modulated white noise method is proposed to generate non-stationary road irregularity with different frequency exponents. Then, the parameter setting problem of the standard white noise is solved. To describe the detrimental effect of time-domain non-stationary road irregularity on the time-varying vehicle speed, a simple and effective lookup table method is presented with the real-time running distance and the corresponding road elevation as input and output, respectively. Next, a half electric vehicle model is developed to describe the interaction between vertical-pitching vibration and longitudinal driving motion. The non-stationary road irregularity-induced power consumptions of both pairs of shock absorbers and the energy slip loss of the driving wheel are analyzed under different frequency exponents and time-varying vehicle speed. The results show that the power consumption of shock absorbers increases when the frequency exponent decreases and the vehicle speed increases. Under the high running speed and large acceleration driving condition, the mean of slip energy loss of the driving wheel is several times larger than the mean sum of the power consumption of shock absorbers.