Application of thin film capacitor in new energy vehicles
Battery, motor and motor control technology are the three cores of new energy vehicles. In the motor drive and control circuit,the main electronic components required are power semiconductor device IGBT, control IC and capacitor, of which IGBT accounts for about 2/3 of the cost.
The core of motor control technology is the inverter technology that needs high-efficiency motor control. The inverter technology that needs high-efficiency motor control needs a powerful IGBT module and a matching DC support capacitor.
For a long time, ceramic capacitors and aluminum electrolytic capacitors are the most common capacitive electronic components in the market. They are widely used in various electronic products, mainly for filtering, frequency modulation, DC isolation and time control in circuit systems.
With the intensification of automobile electrification, the voltage and output power of automobile circuit system have been
greatly improved, and the key components have stricter requirements on the withstand voltage and impact resistance of electronic
components. The change of working conditions puts forward new requirements for the performance of capacitive components in electronic systems, which drives the demand for thin film capacitors in the automotive industry.
Thin film capacitor is the main component in the driving circuit of electric vehicle, which mainly plays a smooth role. The
inverter converts the DC current of the battery into a voltage with small change through the converter, and then converts it into a rectangular wave similar to the AC through the IGBT switching element. The resulting surge voltage is very large, which needs to be eliminated by using a smoothing capacitor.
Early smoothing capacitors used to use aluminum electrolytic capacitors. However, in order to improve efficiency, the maximum voltage of motor drive was increased from 500V to 650V. The withstand voltage of aluminum electrolytic capacitors was insufficient, and thin-film capacitors became the mainstream. Prius began to use thin-film capacitors from the second generation.
In the field of new energy vehicles, the existing aluminum electrolytic capacitors will be partially replaced by thin film
capacitors in the future. At present, more and more companies have used film capacitors to replace electrolytic capacitors. BYD "Qin" and Tesla Model 3 both use thin film capacitors.
At the same time, in dc/dc, motor control system, battery management system and other high-voltage electrical units, the use of thin-film capacitors will also increase with the promotion and popularization of new energy vehicles.