of output current amplitude at low , while the corresponding harmonic component reaches as high as 48.8% at the high . Modeling of and self-heating characteristics: the models of electrolytic and film ESR ESR capacitors are derived and experimentally validated. Two dc-link capacitor designs are used for the comparative evaluation. The of scheme II (film capacitor) is always lower than that of ESR scheme I (electrolytic) throughout the frequency spectrum. The value of scheme I ESR decreases with increasing temperature, which is more significant than that of the scheme II. Furthermore, the values and frequency spectra of the dc-link capacitor current are RMS analyzed. The self-heating effect is subsequently considered and numerically evaluated by using the iterative simultaneous solution for core temperature and ESR by electro-thermal coupling method to predict the core temperature. Lifetime estimates are based on core temperature. Experimental evaluation of two design schemes: The applications and performance of electrolytic capacitors (scheme I) and film capacitors (scheme II) were tested and compared and evaluated in terms of power loss, core temperature, lifetime and battery current harmonics based on a practical 80kW permanent-magnet motor drive system. The comparison verifies that the film capacitor application shows significant advantages shown by the improved power density, low power loss, low parasitic inductance, and long lifetime. The capacitor power loss introduced by the scheme II is roughly half of the value of scheme I due to the lower ESR value. The analysis shows that the values of capacitor core temperature are close to each other in both schemes. At the rated ambient temperature of 65 oC, the lifetime of the film capacitors is ten times longer than that of scheme I. Regarding to the battery ripple current, both schemes meet the 10% upper bound limit considering the practical EV system layout. Further, the parasitic inductance is reduced to 34 nH in contrast with the value of 100 nH for scheme I. The power density of 13.3 kW/L was achieved by applying the proposed scheme II, which is compared to the PDV of 2.99 kW/L for scheme I.
of output current amplitude at low , while the corresponding harmonic component reaches as high as 48.8% at the high . Modeling of ESR and self-heating characteristics: the ESR models of electrolytic and film capacitors are derived and experimentally validated. Two dc-link capacitor designs are used for the comparative evaluation. The ESR of scheme II (film capacitor) is always lower than that of scheme I (electrolytic) throughout the frequency spectrum. The ESR value of scheme I decreases with increasing temperature, which is more significant than that of the scheme II. Furthermore, the RMS values and frequency spectra of the dc-link capacitor current are analyzed. The self-heating effect is subsequently considered and numerically evaluated by using the iterative simultaneous solution for core temperature and ESR by electro-thermal coupling method to predict the core temperature. Lifetime estimates are based on core temperature. Experimental evaluation of two design schemes: The applications and performance of electrolytic capacitors (scheme I) and film capacitors (scheme II) were tested and compared and evaluated in terms of power loss, core temperature, lifetime and battery current harmonics based on a practical 80kW permanent-magnet motor drive system. The comparison verifies that the film capacitor application shows significant advantages shown by the improved power density, low power loss, low parasitic inductance, and long lifetime. The capacitor power loss introduced by the scheme II is roughly half of the value of scheme I due to the lower ESR value. The analysis shows that the values of capacitor core temperature are close to each other in both schemes. At the rated ambient temperature of 65 oC, the lifetime of the film capacitors is ten times longer than that of scheme I. Regarding to the battery ripple current, both schemes meet the 10% upper bound limit considering the practical EV system layout. Further, the parasitic inductance is reduced to 34 nH in contrast with the value of 100 nH for scheme I. The power density of 13.3 kW/L was achieved by applying the proposed scheme II, which is compared to the PDV of 2.99 kW/L for scheme I.
IEEE_EV_PowerDensity_ver3b-pa2.docx