In the past 100 years of development, the environment of auto industry is going through tremendous changes. In the past, the development of automobiles focused on "environment", "safety", and "comfort and convenience". Nowadays, small cars, hybrid electric vehicles, electric vehicles and fuel cell vehicles are attracting more and more attention around the world auto industry. In response to the "environmental protection problems" caused by global warming, the "energy problems" caused by high crude oil prices, and the "resource problems" caused by lack of metals, water and food worldwide, automobiles will continue to develop with the key characteristics of "electronization", "electrification" and "system integration" in the future. The core members of SIMTEK have many years of R&D experience cooperating with the world-famous OEMs, involving the joint development of electric drive systems with German R&D institutes, the cooperation with leading Japanese automobile companies in fuel cell R&D projects and so on. SIMTEK combines with its own R&D capabilities and the experience accumulation to provide system modeling and simulation solutions for the development of new energy vehicle electric drive system and fuel cell system, and assist the top-down design and development of new energy vehicle industry in China.
Power Performance of BEV Powertrain|Energy Consumption Analysis of HEV|Design and Optimization of Thermal Management System
Power Performance of BEV Powertrain
Platform: Modelica（Dymola），SIMTEK New Energy Vehicle Library
As the addition of electrification, new energy vehicles are more energy-saving and environmentally friendly than traditional fuel vehicles. However, at the same time, the overall structure and control system are more and more complex than before. Therefore the computing simulation technology will greatly improve the speed and quality of development in the process of research and development. For new energy vehicles, with the help of electric drive of motor, the power performance has been greatly improved, and 100 km acceleration performance is better than that of the same level of fuel vehicles.
For the analysis of the acceleration performance of an A-level BEV, the parameters of each core component can set by using the multi-disciplinary system simulation software Dymola and the new energy vehicle model library. The acceleration time, the output of the motor and the state change of the battery can be calculated quickly.
Fig. 1 shows the typical BEV model in the New Energy Vehiclel Library. During the design verification in the early stage of R&D, users can obtain the power performance of BEV quickly by re-setting the characteristics map of the batteries and motors, and other key parameters based on the design data in the model. In Figure 2, it shows the output of torque, speed and motor power during the 100 km acceleration process in 11.5s. So as to customers can analyze whether the power configuration of the BEV can meet the market demand.
Energy Consumption Analysis of HEV Powertrain
Platform: Modelica（Dymola），SIMTEK New Energy Vehicle Library
As the change of vehicle powertrain system to electrification, the vehicle structure has become more different and complex than before casuse by the more and more interactions between vehicle subsystems. The functions and integration of subsystems have become more closely and interdependent, which means that engineering departments, which work independently before, now must collaborate more extensively to develop the best solutions at the vehicle level.
New energy vehicles are more energy-saving and environmentally friendly than traditional fuel vehicles, but at the same time, the structure and control system of the whole vehicle are more complex. Therefore, the computing simulation technology can greatly improve the speed and quality of development in the process of research and development.
Based on the new energy vehicle model library, the energy consumption of a class A HEV under WLTP test conditions is analyzed. Fig. 1 shows the HEV powertrain structure based on power splitting, which is tested under the condition that the initial SOC of the power battery is 0.4. In Figure 3, it shows that during the test process, the motor power is the major output , and the braking force gives a feedback recovery, so that the engine only intervene at the higher power output point. Therefore, the HEV's 100 km fuel consumption is only 1.8L under the test condition , which is much lower than the same level of fuel vehicles.
Design and Optimization of Thermal Management System
Platform: Modelica（Dymola）， Modelon LCL，Modelon HEL
With the development of new energy vehicles, more and more OEMs invest more resources in the R&D and manufacturing of new energy vehicles. Compared with traditional automobiles, thermal management of new energy automobiles requires more strict requirements, and the system structure is more complex. Thermal management system mainly includes battery thermal management system, air conditioning system, electric control cooling unit of motor and cooling unit of brake system, etc. The cooling demands of air conditioning system, battery, electric drive and other subsystems should be considered comprehensively.
In order to shorten the research and development cycle of new energy vehicle thermal management system with high quality and reliability, the modern design method based on virtual model is widely used in the auto industry, and gradually replacing the traditional physical test method. A virtual test scenario based on the model can predict the system performance under the actual driving cycle. Furthermore, it can be used for multi-schemes evaluation and rapid optimization verification in the early stage of R&D to reduce or avoid errors or problems in the middle and late stages.
Balancing the cooling and energy requirements at the system level, users can implement the model-based system design/optimization and control algorithm design. And users can model a thermal management system that takes into account of fuel economy and vehicle thermal management comprehensively:
Model-based Development of Vehicle Fuel Cell System
Platform: Modelica（Dymola），Modelon FCL
Fuel cell is a complex system involving multi-physical strong coupling. The research relates to electrochemistry, electrocatalysis, thermodynamics, micro-scale heat and mass transfer, multi-phase fluid dynamics, automatic control and many other disciplines. The strong coupling between subsystems is easy to effect each other, which may make the downstream experiment and analysis inconvenient. The test conditions are strict so that the under-tested stack is easy to be damaged. Modeling and simulation technology can cut the cost of system optimization design and performance test and analysis.
Based on Modelica language, the vehicle model is developed on Dymola platform, and the parameters of fuel cell system can be well calibrated and optimized. When the fuel cell system model is completed, it is need to bulid the fault model (random fault and specific fault) and the durability model for reliability and durability testing.
Development of 100 kW Switched Reluctance Motor and Controller for Bus
Platform：Modelica（Dymola），SIMTEK SRM Library
Facing with the dual pressures of energy shortage and environmental protection, how to achieve sustainable development of the auto industry is a huge challenge for all of countries today. Electric Vehicle (EV) and Hybrid Electric Vehicle (HEV) have become the focus of automobile manufacturers' research and development, which can realize the diversification of automotive energy and achieve energy-saving and emission-reducing. As the key parts, motor and control drive unit have gradually become the focus of research. There are many kinds of motors available, and their performances have their own advantages and disadvantages. Among them, the switched reluctance motor drive system (SRD) is the better choice because of its simple structure, unique performance, high energy density and low heat loss.
Based on FEM and Modelica language, users can set up the 1D-3D coupling dynamic simulation. Through motor-in-Loop testing, the design of motor can be well verified. According to the actual operating conditions, it is easy to realize the design and optimization of motor control system, which is the best way to develop SRD.
Delivery of switched reluctance motor models with multiple stator-rotor configurations
Development of power driving unit model
Development of motor control algorithms: Current Chopper Control | Current PWM Control | Direct Torque Control
Based on the SIMTEK SRM library, a 100KW SRM and controller models are set to evaluate the rationality of SRD design, and the design and optimization of control system are completed based on specific performance indicators.