Three-port charger DCDC starting control method

Abstract

The invention discloses a three-port charger DCDC starting control method. A charger comprises a PFC module, a primary side conversion module, a transformer, a secondary side high voltage conversion module and a secondary side low voltage conversion module. After DCDC starting, the PFC capacitor voltage Vc in the PFC module is detected, when the PFC capacitor voltage Vc is smaller than a voltage threshold Vbus, the secondary side low voltage conversion module is closed, and the secondary side high voltage conversion module pre-charges a PFC capacitor in the PFC module; and when the PFC capacitor voltage Vc is not smaller than the voltage threshold Vbus, the secondary side low voltage conversion module is made to work, and the secondary side high voltage conversion module carries out DCDC starting on the secondary side low voltage conversion module. The defects of an existing magnetic integration scheme technology are overcome, the problem that the module is shut down due to triggeringof HV high-voltage side overcurrent protection under the conditions of low voltage, short low-voltage slow start time and the like of Cbus voltage is solved by controlling the switching time sequenceof a low-voltage end power tube, and compared with a high-voltage HV primary/secondary side series relay scheme, the method is higher in reliability and simple in control mode.

Description

technical field [0001] The invention relates to the technical field of electric vehicle charging, in particular to a DCDC start-up control method for a three-port charger. Background technique [0002] With the demand for energy saving and emission reduction, as well as the control of air pollution, new energy vehicles are gradually commercialized in the market, and electric vehicles are the main force of new energy vehicles. As the vehicle has stricter requirements on DCDC performance parameters, there are strict requirements on the voltage rise time of the low-voltage LV terminal. For physical integrated circuits, this requirement can be met by speeding up the rise rate of the LV current loop, but for the magnetic integration scheme DCDC starts, energy flows from HV to Cbus and LV sides at the same time (see topology figure 1 ), when the internal Cbus voltage of the charging module in the vehicle is low, the Cbus capacitive capacity is large, and the slow-up rate of the L...

AI Technical Summary

Problems solved by technology

For physical integrated circuits, this requirement can be met by speeding up the rise rate of the LV current loop, but for the magnetic integration scheme DCDC starts, energy flows from HV to Cbus and LV sides at the same time (see topology figure 1 ), when the internal Cbus voltage of the charging module in the vehicle is low, the Cbus capacitive capacity is large, and the slow-up rate of the LV cu

Images