A calculation method of Al-caps hotspot temperature with ripple frequency and heat dissipation

Aluminum electrolytic capacitors（Al-caps） are an essential components of charging devices, and the real-time acquisition of their hotspot temperature information plays an important role in the remaining life prediction and temperature protection of charging devices. The traditional hotspot temperature calculation model ignores the frequency characteristics of ESR and the influence of air cooling and other heat dissipation conditions on thermal resistance, which seriously affects the calculation accuracy of hotspot temperature. To address the issues above, this paper proposed a hotspot temperature calculation method that integrated the effects of ripple current frequency characteristics and heat dissipation conditions on capacitor heat generation and thermal conductivity.Thus, the hotspot temperature of capacitor can be calculated in real time under the multiple effects of ripple current,heat dissipation conditions and ambient temperature. Finally, the effectiveness of the proposed method is verified with a 30kW electric vehicle charging module.