When designing and deploying advanced solutions for harsh automotive environments, designers need interactive simulation** tools that are user-friendly, fast, and less hardware-intensive. The adoption of distributed intelligence can unleash system performance, but it requires system resilience and real-time feedback capabilities.
In the automotive industry, designers need to address, reduce, and prevent serious issues that can lead to damage to critical components such as engine control modules (ECMs) or other electronic control units (ECUs). These system failures can lead to accidents or other safety hazards.
To combat these hazards, automakers employ a variety of protective measures, such as fuses, circuit breakers, and overvoltage protection devices, as well as thermal management technologies that prevent critical components from overheating.
Accurate simulation tools help identify potential problems before they occur, allowing engineers to make necessary modifications or adjustments to the design to prevent them from occurring in the first place.
In addition, simulations can be used to optimize the design of electrical systems to handle the maximum currents and voltages that may be encountered, making automotive systems safer and more reliable.
Comprehensive simulation capabilities are essential
In the development of next-generation vehicles, engineers face many challenges in power distribution, requiring a distributed intelligence approach to address several key factors simultaneously:
Vehicle toughness. Energy efficiency.
Sustainability. Resilience to unforeseen situations such as accidents, bad weather, equipment failures, etc., is critical to vehicle resilience. Energy efficiency plays a key role in reducing power consumption, carbon emissions, and maintenance costs, while helping to improve vehicle performance and reliability. Sustainability is a key factor in reducing the environmental impact of vehicles and promoting low carbon.
To achieve these goals, engineers must use innovative solutions and concepts validated by comprehensive simulations to develop advanced automotive systems that meet the needs of the industry and deliver a safer, more reliable, more sustainable, and more enjoyable driving experience. The intelligent power switches used in the power distribution system are complex electronic components that need to undergo electrothermal simulation experiments to ensure optimal performance.
Electrical simulation experiments are indispensable for analyzing the electrical behavior of power switches, including the ability to handle high-voltage currents of switches, response times, and the ability to detect and isolate faults. On the other hand, analyzing the heat generated by the switch during operation requires thermal simulation experiments, because the heat can affect the performance and reliability of the switch. By conducting electrothermal simulation experiments, engineers can optimize the design of the smart switch to ensure that it meets the performance requirements of the design while maintaining a safe operating temperature. Analog verification methods can improve the energy efficiency, reliability, and safety of the power distribution system, while ensuring that the system implements reasonable and effective protection mechanisms and diagnostic functions.
1.Learn about the productTo ensure the best choice, simulations must be done in a user-friendly, customizable, interactive environment so that you can quickly understand the behavior of the smart switch. The first step is to determine which products meet the electrical requirements.
ST's electrothermal simulator Twistersim is the ideal tool for this purpose, designed specifically for the selection of VIProPOWER products, including intelligent high- and low-side drivers, as well as full-bridge topologies for motor control. The simulation tool accurately selects candidate devices from a list and provides basic product information. As a result, designers can quickly and easily evaluate the performance of different smart switches and select the most suitable switch for a particular application, as shown in Figure 1.
Figure 1: Vipower Smart Drive Preselection.
Based on a variety of input data such as supply voltage, device topology, number of channels, load type and characteristics, power supply type, ambient temperature, and PCB power dissipation area, the simulator can provide valuable information about the estimated maximum junction temperature (TJMAX) for fast and efficient product preselection.
This information is critical to selecting the appropriate on-state resistance (RON) for each channel and ensuring that the thermal budget in operation meets the device's absolute maximum rating.
2.Gain insight into performanceTo study the electric-thermal behavior of the driver, the simulator generates a schematic circuit that contains preselected devices and input and output circuits connected to the battery and load, respectively (Figure 2).
Figure 2: Circuit diagram of the Vipower driver simulation experiment.
Where: vbatt is the battery voltage;
vin is the input voltage of the microcontroller;
Rline In and Rline Out are wire parasitic resistors at the input and output of the driver.
Before you start the simulation, you need to perform the definition step to customize the project parameters. In this phase, the designer determines the parameter values and analog settings of the components in the circuit diagram.
The parameter values of the components in the circuit diagram are critical to determining the behavior of the circuit and must be carefully sized to ensure that the circuit meets the performance specifications.
Analog settings define what operating conditions a designer wants to reproduce and analyze through simulation experiments, for example, a designer might want to examine voltage and current waveforms in a circuit, determine power consumption, or evaluate the thermal behavior of a circuit.
By customizing project parameters and setting simulation variables, designers can ensure that the simulation results accurately reflect the behavior of the circuit and provide the information needed to optimize the design (Figure 3).
Figure 3: The simulation definition process.
One of the great benefits of using Twistersim for simulation experiments is that the results can be displayed in real time during the simulation. This feature allows designers to monitor the behavior of a circuit during the simulation process and quickly identify problems or areas for improvement.
The real-time display of simulation results can help designers improve the efficiency and effectiveness of design optimization, for example, when the simulation results show that the circuit is drawing too much current or the temperature is rising too fast, the designer can quickly adjust the circuit parameters and immediately see the impact of the parameter changes on the simulation results.
This feature saves time and resources because designers don't have to wait until the end of the simulation to quickly identify and resolve issues. TwistersIM's real-time display of simulation results can improve the efficiency and effectiveness of design optimization, thereby improving the energy efficiency, reliability, and safety of power distribution systems.
3.Tailor the simulation results to your needs
Figure 4: Tailoring curves and charts to data visualization.
Engineers can modify simulation parameters, data, and visualizations to meet their specific needs, make informed decisions, and get the best results. The simulator provides a variety of tools for analyzing and optimizing VIPopower circuits, such as heat maps, current-voltage waveforms, and power consumption analysis, as shown in Figure 4.
Designers can use Twistersim to design and develop efficient and resilient drives with effective diagnostic and protection functions by optimizing the performance and reliability of their designs, reducing the risk of failure due to thermal or electrical stress, and integrating error reproduction and limit parameter logging. In addition, this design approach can reduce harness size and weight, thereby reducing the vehicle's carbon footprint.
Critical scenesIn harsh automotive ecosystems, especially where repeated short-circuit events can lead to thermal shutdown (TSD), it is critical to consider implementing thermal protection mechanisms.
In this case, the driver attempts to reboot the system with power limiting protections (maximum current and thermal hysteresis cycles) and maintains TSD mode until the overheating problem is resolved.
TwistersIM also has this specific control function, taking the high-side driver VND9012AJ (an intelligent power switch developed with ViPower M0-9 technology) as an example, TwistersIM can accurately reproduce the operation of the switch and then compare the simulation results with the experimental data, as shown in Figure 5.
Figure 5: Comparison of the simulation results of the VND9012AJ with the experimental data in the case of repeated short-circuit events.
Where: iout is the output current of the driver;
DT is the time difference between the simulated results and the TSD events in the measured data.
The simulation results show that TwistersSIM is an efficient tool to accurately simulate current limiting and thermal shutdown (TSD) triggering conditions for thermal protection mechanisms.
The analog data error of the output current value is less than 2%, while the TSD occurrence time error is about 08ms。This proves that Twistersim has a high rate of correct system behavior under real-world conditions.
Conclusion
With the advent of the next generation of automobiles, engineers are challenged to develop advanced solutions, and deploying distributed intelligence can unleash powerful performance in systems. To achieve this, new designs must prioritize energy efficiency and resilience, and a comprehensive range of simulation tools is essential to ensure accuracy and effectiveness.
By taking full advantage of TwistersIM's capabilities, developers can optimize the new Vipower drive design for the highest performance and reliability while minimizing the risk of failure caused by thermal or electrical stress, paving the way for green and low-carbon sustainability.
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