1 Objective
The present tutorial aims to present a study on the design of different types of electric vehicles (EVs) and batteries for EVs when subjected to a given driving cycle, while the major differences between existing batteries are evidenced in terms of weight and volume. Therefore, it is necessary to know the entire electrical system of the vehicle in order to assess the load power as a function on the required number of batteries for the proper EV operation. As a result, a worksheet is generated using MATLAB, which can be applied in the design of distinct EVs considering key parameters such as front area, mass, drag coefficient, among others.
This tutorial also includes the modeling and design of five battery types (NiCad, NiMH, Li-ion, Zebra, and Lead-acid), determination of acceleration and top speed ranges, as well as the complete modeling of EVs.
2 Proposed Approach
EV modeling is performed for three types of vehicles, namely, one car, one motorcycle and one bus whose rated powers are 60 kW, 8 kW, and 200 kW, respectively.
This task comprises the following steps:
1. Brief description of the main EV characteristics (series, parallel and series/parallel configurations).
Modeling of Li-ion, lead-acid, sodium, NiMH, NiCad and lithium titanium batteries. A Ragone plot will also be presented for the studied batteries.
2. Estimation of efficiency maps (torque vs. speed curves) for induction motors, PMSMs (Permanent Magnet Synchronous Motors), and SR (Switched Reluctance) motors, while real maps for a maximum speed of 12,000 rpm are also provided.
3. Use of international standard driving cycles in order to assess EVs’ performance.
4. Definition of the maximum speed, acceleration, battery mass, number of required batteries, battery volume, among other parameters for distinct motors and batteries.
5. Estimation of efficiency for components used the simulation, front area, friction coefficient, drag coefficient, mass, velocity ratio (G/r), among other parameters as based on actual values.
6. Plotting some curves including torque x speed, maximum engine power versus time, tractive effort, current through the battery and other components, engine efficiency, etc considering a few driving cycles.
7. Definition of the model with the best performance (in terms of acceleration, and top speed range) for each type of vehicle (car, bike and bus) based on the obtained results.
8. Modify parameters regarding auxiliary accessories such as air conditioning, vehicle lighting, among others, and recalculate the EV’s range for the best identified models.
9. Compare the obtained results with those achieved by a constant speed driven vehicle.
10. Calculation of actual values involving acceleration, top speed and range for practical EVs (cars, motorcycles, and buses) and comparison with simulation results.
