Multiphase LLC resonant converter

A multiphase LLC resonant converter comprising:

• N phases, where N represents an integer equal to or greater than two;
• and
• N resonant converters connected in parallel to a direct current power supply and configured to operate with a phase difference of 360°/N;
• wherein
• each of the N resonant converters includes:
• an upper switch and a lower switch connected in series between a positive electrode and a negative electrode of the direct current power supply;
• a resonant inductor including a first end connected to a connection point of the upper switch and the lower switch;
• m lower conversion circuits, where m represents an integer equal to or greater than two, each including a transformer including a primary winding and a secondary winding, a first resonant capacitor and a second resonant capacitor each including a first end connected to the primary winding, and a rectifier connected to both ends of the secondary winding, the primary winding and the first resonant capacitor being connected between a second end of the resonant inductor and the negative electrode of the direct current power supply to configure the multiphase LLC resonant converter to operate by on/off operations of the upper switch and the lower switch together with the resonant inductor;
• n upper conversion circuits, where n represents an integer equal to or greater than two, each including a transformer, a first resonant capacitor and a second resonant capacitor, and a rectifier, a primary winding and the first resonant capacitor being connected between the second end of the resonant inductor and the positive electrode of the direct current power supply to configure the multiphase LLC resonant converter to operate by the on/off operations of the upper switch and the lower switch together with the resonant inductor;
• a lower adjustment inductor connected in parallel with the primary windings of the m lower conversion circuits;
• an upper adjustment inductor connected in parallel with the primary windings of the n upper conversion circuits;
• a second end of the second resonant capacitor in the lower conversion circuit is connected with the second end of the second resonant capacitor in the lower conversion circuit of another phase at a common neutral point that connects the phases, and a second end of the second resonant capacitor in the upper conversion circuit is connected with the second end of the second resonant capacitor in the upper conversion circuit of the other phase at the common neutral point that connects the phases;
• outputs of the m lower conversion circuits and the n upper conversion circuits in each of the N resonant converters are star-connected at the common neutral point via the respective second resonant capacitor;
• an intermediate external terminal connected to a connection point of the second end of the resonant inductor and a first end of each of the primary windings of the upper conversion circuit and the lower conversion circuit;
• a lower external terminal connected to a connection point of a second end of the primary winding of the lower conversion circuit and the first end of the first resonant capacitor;
• and
• an upper external terminal connected to a connection point of a second of the primary winding of the upper conversion circuit and the first end of the first resonant capacitor;
• wherein
• the lower adjustment inductor is connected as an external inductor between the intermediate external terminal and the lower external terminal, and the upper adjustment inductor is connected as an external inductor between the intermediate external terminal and the upper external terminal.