Abstract: One of the limiting factors of the refrigerating capacity range of household air conditioners under high temperatures is the life of the electrolytic capacitor on the driving board of the outdoor unit. At present, the service life of the electrolytic capacitor is generally guaranteed by limiting the operating frequency of the compressor, which causes a waste of the cooling capacity of the air conditioner. By evaluating the influencing factors of electrolytic capacitor life, the relationship between surface temperature, self temperature rise and life of electrolytic capacitor is analyzed. Without changing or adding hardware sensors, the methods of electrolytic capacitor ripple voltage estimating temperature rise and linear fitting estimating surface temperature are proposed to estimate the life of electrolytic capacitor in real time, and then dynamically adjust the operating frequency of compressor under high temperature. Realize the adjustment of compressor operating frequency based on user usage, and for most users, can increase the air conditioning cooling capacity by more than 5% under high temperature.

Key words: Life of electrolytic capacitor, Electrolytic capacitor temperature, Temperature rise of electrolytic capacitor, Ripple current, Ripple voltage, Frequency of compressor