Research On Real-time Calculation Model Of EV Energy Consumption Based On VA Distribution

Because of vehicle tenure rapid increasing, the energy consumption became more andmore huge and environmental pollution is increasingly severe. Nowadays thesignificant topics of vehicle area are saving energy and reducing emissions. Thecreation of the EV that can be driven by electric power and is a new system which canachieve transport of high efficiency and cleanness opened a new horizon. However,some problems also exist about EV. The one of it is battery, the key technology of ithave limitation, so that driving range is short compared to internal combustion vehicle.In order to solve the problem by held technology, one of the main methods is that theroute of saving energy is chosen so that can reduce the energy consumption of EV inunit time. It can increase the range in the event that the available energy of batterynever changed at long time because of the technology. All of it need calculate theenergy consumption of EV.In this thesis EV energy consumption real-time calculation model that have highaccuracy and computing efficiency based on VA (velocity and acceleration)distribution have been developed.In the thesis, some contents have been researched.1) The energy consumption calculation model based on velocity time series has beenbuilt and the energy consumption of that at different test route between starting pointand terminal point about Changchun city was computed by using the model. In thisprocess the disadvantage of the energy consumption model based on velocity timeseries can be exposed. This model is inefficient since the computing time becomesincreasingly long with the time length of velocity time series ascending.2) The velocity time series were analyzed by the theory of probability and statisticsand the energy consumption calculation model based on VA distribution has been built.The energy consumption calculation model based on velocity time series has thedisadvantage in time efficiency and the energy consumption calculation model basedon VA distribution can solve the problem. In the process of researching velocity timeseries of city route, the characters of it that the state of vehicle velocity obeys markovproperty and VA distribution were found. So that the velocity time series have ergodic property. According to the theory of ergodic property, the time average of the energyconsumption that is associated with velocity equal statistical average of it. Thealgorithm of the energy consumption calculation model based on velocity time seriesmainly is differential and then compute the energy of every data point. Because theelongation of time length of velocity time series led to argument of the number of datapoint. The computing time of the energy consumption calculation model based onvelocity time series is in connection with the number of data point. However, theenergy consumption computing model based on VA distribution is on the basis of VAstate space. In the route of city the number of vehicle operation states is limitation.Even if the length of velocity time series should ascend, the number of vehicleoperation states wouldn’t rapidly go up. The computing time of model is beginning tostabilize in short time.3) The equivalent between the energy consumption calculation model based on VAdistribution and the energy consumption calculation model based on velocity timeseries was proven. On the basis of it, the reasonable number of VA states wasanalyzed and adopted in order to reduce the computing error compared to the energyconsumption calculation model based on velocity time series. The computing error ofenergy consumption calculation model based on VA distribution is in connection withthe number of VA states. If the number should be less, the vehicle operation statescan’t be completely expressed and if the number should be extremely large, thecomputing time would ascend about dealing with VA states even if it can contain allof vehicle operation states. So that computing efficiency of the model cut down.4) The comparison of energy consumption results between energy consumptioncalculation model simulation computing and test data real-time computing accordingto the data of energy consumption collected in road test demonstrate that the result ofthe energy consumption calculation model based on VA distribution is more accuracy.