The invention discloses a vehicle-mounted composite power supply
system of an
electric vehicle and a control method. Through a
voltage and current acquisition circuit, a
voltage value and a current value of a motor
inverter end, and
voltage values of a battery set and a
supercapacitor are obtained, and the processed to obtain required power, battery set SOC and
supercapacitor SOC, which are used as decision-making input variables of a
fuzzy logic control module. According to actual operation working conditions of the
electric vehicle, a proper logic threshold value control strategy is formulated and by use of fuzzy control, fuzzification is performed on fixed rule parameters in a logic threshold, so rules are further refined, control thinking is further precise and results are further optimized. Compared with real-time power, the
peak value of actual average power and the
switching frequency are greatly reduced. By combining the power
hysteresis control, the
switching frequency of working
modes of the
system and the output frequency of the battery set are further improved,
energy loss, caused by
mode switching, of a vehicle-mounted double-
energy system is reduced, service lifetime of the battery set is prolonged and efficiency and stability of the
system are improved.