Introduction
Currently, electric vehicles to fuel cell (FCEV) become the main direction of technological innovation of the automobile. System for Fuel Cell Electric Vehicle Power consists of an engine fuel cell, DC / DC converters, battery, motor controller (inverter) and the DC motor, system acquisition CAN bus data and composition of Figure 1. Including DC / DC converter controls the production of fuel cells and energy transmission and conversion, fuel cell electric vehicle key components. In the fuel cell electric vehicles for the course, DC / DC converter in which the electromagnetic environment is very complex and many forms of electromagnetic interference, has seriously affected the normal operation of the DC / DC converter. Therefore, the study with DC DC Converter VEGF electromagnetic compatibility DC / DC and battery electric vehicles to fuel and reliable operation is important. Dell Inspiron 1721 battery Dell Inspiron E1505 battery
High Power DC / DC converter main source of interference and electromagnetic compatibility design
VEGF with DC / DC converter is a device for power conversion, electromagnetic compatibility electromagnetic environment in VEGF has a significant impact. VEGF with DC / DC working on the world a strong electromagnetic interference, not only interfere with the VEGF, but also affects the DC / DC converter control system of their own work. Therefore, VEGF to improve system performance must VEGF with DC / DC The search for electromagnetic compatibility, electromagnetic interference generated by its (EMI) effectively inhibited. Dell Latitude D830 battery Dell Inspiron 1150 battery
High Power DC / DC converter main source of interference
VEGF with DC / DC power converter is generally larger, often choose as IGBT power switches. IGBT power switches work produced during the high dv / dt and di / dt and the increase of peak current and voltage, which is VEGF high power DC / DC converters to generate the most fundamental causes of electromagnetic interference . In addition, the power switch on and off instantly, as inductance and distributed capacity of the existence of the inductor is a high frequency oscillation, these factors have a strong electromagnetic interference, which VEGF high power DC / DC converter performance particularly sensitive. This electromagnetic interference severely affected vehicle controller and CAN communication, communication can often lead to error, not the normal communication. CAN communication interference waveform is displayed after the transfer. From the figure, it is clear that the converter switching noise superimposed on the pulse on the CAN communication and the increase was significant. In addition, EMI will also make a serious high-power DC / DC output ripple of the converter is too large, the ripple is too large direct impact on high power DC / DC converter performance. Dell Vostro 1500 battery Dell XPS M140 battery
High Power DC / DC measures electromagnetic interference suppression
Currently, inhibition of the high power DC / DC EMI measures reduce the main sources of interference intensity of electromagnetic interference, electromagnetic interference cut the transmission, distribution and rational use of sensitive components and the shield design signal ground.
● reduce the intensity of the interference of electromagnetic interference
High Power DC / DC converters generate electromagnetic interference is mainly due to the rapid changes in voltage and current, and thus need to minimize the voltage and current exchange rates (du / dt and di / dt) . The most common method is to increase the absorption circuit, the circuit can inhibit the absorption of electromagnetic interference, the basic principle is that when the switch is turned off to provide diversion, savings in the parasitic absorption parameters of energy distribution, thus preventing the appearance of interference. More technology soft switching converter is the focal point of research in recent years [4], VEGF high power DC / DC converter using passive soft-switching resonant flexible technology can significantly reduce the process of switching / dt and di / dt, not only to reduce switching losses, but also significantly reduces electromagnetic interference. In addition, by optimizing the power switch control IGBT, selecting the power button IGBT drive voltage and gate resistance, may also reduce interference from high power DC / DC EMI. Dell Vostro 1710 battery Dell Latitude D810 battery
● cut channels of electromagnetic
VEGF high power DC / DC electromagnetic interference generated mainly by conduction disorders. The most common method is DC / DC converter input and output filter capacitor installed. To reduce VEGF high power DC / DC on the CAN communication interference, in converter input and output plus an appropriate amount of capacitors grounded, effective communication can improve the waveform.
VEGF in high power DC / DC converter, the output voltage or current ripple is an important indicator of food. Figure 4 in the high power DC / DC converter to connect the CLC filter output, the converter output voltage waveform smooth, reduced switching noise, filtering is obvious. dell inspiron 6400 battery dell inspiron 640m battery
In addition, VEGF high power DC / DC converter switch to a dozen kHz frequency IGBT turn on and off the circuit can have a high incidence of harmonic current output voltage fuel cell. Therefore, DC / DC converter input and output are generally parallel capacitor (electrolytic capacitors without any sense of capacitors in parallel). No sense capacitor filter circuit can occur because of interference radiation frequency resonance, while the electrolytic capacitor to stabilize the output voltage of fuel cells and reduce the intensity of the radiation, and reduces the DC / DC output voltage ripple.
● rational distribution of sensitive components dell inspiron 6000 battery dell inspiron 630m battery
VEGF high power DC / DC converter contains many sensitive components (such as Hall sensors in progress), these sensitive components are very sensitive to electromagnetic interference. VEGF in high power DC / DC Converter for switching on actual layout of components usually sensitive to the power switch in the IGBTs, freewheeling diode and a transformer at high frequency, the farther Xian stranded signals and reduce the wiring distance This can significantly reduce the current noise signal, improve the control performance. Meanwhile, VEGF high power DC / DC converter wiring connection, we should try to be sensitive to the signal line of IGBT power switch, diode and high-frequency transformers and other strong sources of interference. At the same time, not with a high voltage AC signal and high frequency pulse signal is put together, should ensure the proper distance. dell inspiron 5150 battery dell inspiron 5160 battery