With the development of modern communication technologies, electrical and electronic devices are used more and more widely in various fields. The electromagnetic energy generated by these devices while working often affects the work of other devices and forms electromagnetic interference (EMI). Especially in automobiles, airplanes and warships, a large number of electronic devices are concentrated in a small space, and the electromagnetic interference between them is very serious. At the same time, due to the increasingly high performance requirements for electronic devices and systems, such as increasing transmitter transmit power and improving receiver sensitivity and reducing the size of devices, the design complexity of electromagnetic compatibility (EMC) and electromagnetic interference is further exacerbated. degree.

The advent of electronic design automation (EDA) software has greatly expanded EMC's design approach and is a practical method for handling potentially multiple EMI in large systems or complex equipment. However, the involvement of simulation software does not mean that engineers no longer need to make engineering judgments in the design. Instead, engineers need to make more engineering judgments based on their professional knowledge and experience. These engineering judgments will all take the form of “known quantity”. Input into the software program, so that the simulation results have more engineering value. Therefore, it is not difficult to find that the main function of simulation software in EMC design is not to make your design more “fool”, but to make you more “intelligence” in the design process and greatly reduce the prototyping process. And testing uncertainty, reducing the number of design iterations, shortening the product development cycle, reducing research and development risk, ensuring product quality and passing test standards.

However, EMC/EMI problems have their own particularities in the application of simulation software design. In general, the process of simulation software for engineering problems is "modeling → replication problem → improving design" because the EMC/EMI problem is characterized by randomness and variability. For example, when a signal on multiple I/O pins of a digital chip on a PCB is flipped at the same time by 0/1, the interference voltage is superimposed on the power pin and the voltage on the pin will exceed the tolerance fluctuation. The range, while the number of pins that simultaneously signal flipping is random, at this point the chip's I / O pins can be seen as the noise source of the synchronous switching noise (SSN) problem, the object of the analysis of the problem for the chip and its peripheral circuits . At the PCB level, the chip is transformed from the object being analyzed into one of the sources of noise in PCB EMI problems. When the research object rises to the device or even the system level, the PCB as a whole is considered to be the noise source of the device. This example reveals that one of the reasons for the randomness of the EMC/EMI problem is the randomness of the noise source. In addition, the diversity of interference pathways also leads to variability in EMC/EMI issues. Therefore, it is difficult to achieve complete “replication” of EMC/EMI problems in a practical project.

Analysis of System EMC Design Based on Simulation Software

Ansoft's "top-down" system-wide EMC design process.

Although it is difficult to achieve "replica problems," as long as the traditional design ideas for components are changed, "precision design" is changed to "margin design," and engineering design methods provided by simulation software are used. EMC/ The EMI problem is also solved. For example, although the size of the field at a certain distance from the AC power source varies with time, in terms of design margin, only the peak value needs to be considered in the simulation, and the problem is simplified.

Electromagnetic compatibility is an integrated discipline. Designers need to go through the specialized fields of microwave, electromechanical systems, PCB SI/PI/EMC, and even chip designs. Completing a complete system EMC design also requires systems, circuits, PCBs, The electromagnetic field simulation tool support includes a comprehensive design of circuit design and optimization, system frequency domain and time domain characteristics. Ansoft can provide designers with such a powerful electromagnetic compatibility simulation platform that includes the above functional modules, and there are rich interfaces between different simulation tools on the platform for co-simulation, so it is very suitable as the electromagnetic compatibility simulation platform of the system. . On such a simulation platform, designers can use virtual physical prototypes to predict the electrical performance of complex systems through complete systems, circuit design, and accurate electromagnetic field simulations. The concurrent design of systems, subsystems, stand-alones, and components enables modern complexities to be realized. Integrated design and concurrent design of electronic systems.

For designers who conduct an overall EMC system assessment, Ansoft offers a "top-down" EMC solution. Designers can first make appropriate engineering judgments based on the results of the system EMC test, and combine the simulation software to locate the problem for the exceeding criteria. At this stage, the designer may not consider the specific structure of the board and the device first, but instead use the appropriate equivalent source analysis method based on the test results. Then, in the design of the equipment level, the parallel design of the board and the chassis is adopted to improve the electromagnetic compatibility of the equipment.

Bathroom Accessories

Dongguan Metalwork Technology Co., LTD. , https://www.dgdiecastpro.com

Posted on