Methods and apparatus for three-phase rectifier with lower voltage switches

A circuit, comprising:

• first, second and third input terminals to receive respective three phase power signals;
• a rectifier coupled to the three-phase power input terminals and having DC output terminals, the rectifier including a first pair of diodes coupled in series across the DC output terminals, a second pair of diodes coupled in series across the DC output terminals, and a third pair of diodes coupled in series across the DC output signals, the rectifier including a series of terminal pairs for load capacitors;
• a first switch pair coupled between the first input terminal and first and second ones of the series of terminal pairs for load capacitors;
• a second switch pair coupled between the second input terminal and the first and second ones of the series of terminal pairs for load capacitors;
• a third switch pair coupled between the third input terminal and the first and second ones of the series of terminal pairs for load capacitors;
• a fourth pair of diodes coupled in series across third and fourth ones of the series of terminal pairs for load capacitors, a point between diodes in the fourth pair of diodes being coupled to a point between switches in the first switch pair;
• a fifth pair of diodes coupled in series across the third and fourth ones of the series of terminal pairs for load capacitors, a point between diodes in the fifth pair of diodes being coupled to a point between switches in the second switch pair;
• a sixth pair of diodes coupled in series across the third and fourth ones of the series of terminal pairs for load capacitors, a point between diodes in the sixth pair of diodes being coupled to a point between switches in the third switch pair.

A circuit, comprising:

• a rectifier having first and second DC output terminals;
• a circuit path coupled across the DC output terminals, the circuit path including first terminals for a first load capacitor, second terminals for a second load capacitor, third terminals for a third load capacitor, and fourth terminals for a fourth load capacitor;
• a first input terminal to receive a phase A signal coupled to the rectifier;
• a second input terminal to receive a phase B signal coupled to the rectifier;
• a third input terminal to receive a phase C signal coupled to the rectifier
• the rectifier including a first pair of series-coupled diodes coupled across the DC output terminals, a second pair of series-coupled diodes coupled across the DC output terminals, and a third pair of series-coupled diodes coupled across the DC output terminals, wherein the first input terminal is coupled to a point between diodes in the first pair of series-coupled diodes, the second input terminal is coupled to a point between diodes in the second pair of series-coupled diodes, and the third input terminal is coupled to a point between the third pair of series-coupled diodes;
• a first switch pair coupled between the first input terminal and a point between the second terminals for the second load capacitor and the third terminals for the third load capacitor;
• a second switch pair coupled between the second input terminal and the point between the second terminals for the second load capacitor and the third terminals for the third load capacitor;
• a third switch pair coupled between the third input terminal and the point between the terminals for the second load capacitor and the third terminals for the third load capacitor;
• a fourth pair of series-coupled diodes coupled from a point between the first terminals for the first load capacitor and the second terminals for the second load capacitor to a point between the third terminals for the third load capacitor and the fourth terminals for the fourth load capacitor, wherein a first node is located between diodes in the fourth pair of series-coupled diodes and switches in the first switch pair;
• a fifth pair of series-coupled diodes coupled from a point between the first terminals for the first load capacitor and the second terminals for the second load capacitor to a point between the third terminals for the third load capacitor and the fourth terminals for the fourth load capacitor, wherein a second node is located between diodes in the fifth pair of series-coupled diodes and switches in the second switch pair;
• a sixth pair of series-coupled diodes coupled from a point between the first terminals for the first load capacitor and the second terminals for the second load capacitor to a point between the third terminals for the third load capacitor and the fourth terminals for the fourth load capacitor, wherein a third node is located between diodes in the sixth pair of series-coupled diodes and switches in the third switch pair.