Advantages of thin film capacitors(II)

2) Good temperature characteristic, wide range of product temperature, can be used from -40 ℃ to 105 ℃ high temperature polypropylene film capacitor, with temperature stability that polyester film and electrolytic capacitor don’t have. 

3) The frequency characteristic is stable, the product high frequency characteristic is good at the present. Most controller switch frequency is about 10 KHZ, which requests that product high frequency performance should is good, for the electrolytic capacitor and the polyester film capacitor, this request is a difficult problem.

4) No polarity, the electrode which can withstand the reverse voltage film capacitor is evaporated on the film of nanometer level metal, the product has no polarity, so it is very convenient for the user, does not need to consider the question of positive and negative electrode; For the electrolytic capacitor, if the reverse voltage of more than 1.5 times un is added to the electrolytic capacitor, it will cause the chemical reaction inside the capacitor. If the voltage lasts long enough, the capacitance will explode, or the electrolyte will flow out as the pressure inside the capacitor releases.

5) the bus voltage of hybrid electric vehicle and fuel cell vehicle has a tendency to increase continuously in order to increase the output power without the need of series and balance resistor. At present, the typical battery voltage supplied to the motor in the market is 280 VV, 330 V and 480 V, and the matching capacitor is not the same as that provided by different manufacturers. However, it is generally possible to choose such as 450 VX 600V / 800V, with capacity from 0.32mF to 2mF, and the rated voltage of the electrolytic capacitor is not more than 500V, so when the bus voltage is higher than 500V, the system can only improve the voltage level of the capacitor bank by means of series electrolytic capacitor. In this way, it not only increases the volume and cost of the capacitor bank, but also increases the inductance and ESR in the circuit.