Synchronized dual active bridge

A method for controlling an electric motor by implementing a synchronized bidirectional rotary dual active bridge, comprising:

• a) providing a rotary transformer having a primary side and a secondary side;
• b) connecting a first inverter being a first full active bridge between an DC power source and said primary side;
• c) connecting a second inverter being a second full active bridge to said secondary side and feeding an output current to a rotor of said electric motor via said secondary side;
• d) continuously transmitting, by a control circuit and via said rotary transformer, synchronization pulses at a switching frequency of said inverters, to operate said second full active bridge independent of said first full active bridge;
• e) processing said synchronization pulses to obtain an essentially square wave signal that independently operates said second full active bridge to feed said rotor with predetermined output current originated from passing power from said DC power source to said second full active bridge, via said rotary transformer;
• and
• f) at the primary side, controlling a phase and an operating duty cycle of said first full active bridge, being in synchronization with said synchronization pulses, to thereby vary the output current provided by said second full active bridge to said rotor.

A synchronized bidirectional dual active bridge power transfer system, comprising:

• a) a transformer having a primary side and a secondary side;
• b) a first inverter being a first full active bridge, connected between a power source and said primary side;
• c) a second inverter being a second full active bridge, connected to said secondary side and feeding a load current via said secondary side;
• d) a control circuit for:
• d1) continuously transmitting, via said transformer, synchronization pulses at a switching frequency of said inverters, to operate said second full active bridge independent of said first full active bridge;
• d2) processing said synchronization pulses to obtain an essentially square wave signal that independently operates said second full active bridge to feed said load with predetermined load current originated from passing power from said DC power source to said second full active bridge, via said transformer;
• and
• d3) controlling, at the primary side, a phase and an operating duty cycle of said first full active bridge, being in synchronization with said synchronization pulses, to thereby vary the load current provided by said second full active bridge to said load.

A system for controlling an electric motor by implementing a synchronized bidirectional rotary dual active bridge, comprising:

• a) a rotary transformer having a primary side and a secondary side;
• b) a first inverter being a first full active bridge, connected between an AC power source and said primary side;
• c) a second inverter being a second full active bridge, connected to said secondary side and feeding the load current to a rotor of said electric motor via said secondary side;
• d) a control circuit, for:
• d1) continuously transmitting, via said rotary transformer, synchronization pulses at a switching frequency of said inverters, to operate said second full active bridge independent of said first full active bridge;
• d2) processing said synchronization pulses to obtain an essentially square wave signal that independently operates said second full active bridge to feed said rotor with predetermined load current originated from passing power from said AC power source to said second full active bridge, via said rotary transformer;
• and
• d3) at the primary side, controlling a phase and an operating duty cycle of said first full active bridge, being in synchronization with said synchronization pulses, to thereby vary the load current provided by said second full active bridge to said rotor.