Phase shift control method for charging circuit

A phase shift control method for a charging circuit, wherein the charging circuit comprises a primary conversion circuit, a first secondary conversion circuit, a second secondary conversion circuit, and a transformer T1 connecting the three circuits, wherein the primary conversion circuit has a first group of power switches Q1 and Q4 and a second group of power switches Q2 and Q3, and the two groups of power switches have opposite switching actions;

• the first secondary conversion circuit has a third group of power switches Q5 and Q8 and a fourth group of power switches Q6 and Q7, and the two groups of power switches have opposite switching actions;
• a first capacitor C1, a first inductor L1, and a primary winding W1 of the transformer, are connected in series between the first group of power switches and the second group of power switches;
• and wherein the charging circuit further comprises a first secondary current collector and a first secondary voltage collector for collecting parameters of the first secondary conversion circuit, as well as a controller connecting all the collectors and all the power switches;
• the controller carries out PWM control on the first and the second groups of power switches in the primary conversion circuit and also carries out PWM control on the third and the fourth groups of power switches in the first secondary conversion circuit at the same time, and further causes a phase angle difference Φ between an ON/OFF waveform of the first group of power switches and an ON/OFF waveform of the third group of power switches;
• the controller receives an output current (Io1) and an output voltage (Vo1) of the first secondary conversion circuit, collected by the first secondary current collector and the first secondary voltage collector, carries out comparison and calculation between the collected output current Io1 and output voltage Vo1 and a preset output current and output voltage, and adjusts the magnitude and positive and negative of the phase angle difference Φ according to the comparison result.