Active rectifier with modulation

A galvanically decoupled system, comprising

• a first subsystem configured to generate a varying current through coupling means;
• and
• a second subsystem comprising a rectification circuit configured to generate a direct current at an output of the rectification circuit subject to an alternating voltage derived from the varying current at an input of the rectification circuit and configured to transmit encoded information to the galvanically decoupled first subsystem;
• the rectification circuit comprising
• coupling means at the input, configured to receive the alternating voltage from the galvanically decoupled first subsystem;
• a first switch arranged between the coupling means and the output, configured to block current in a first direction and to conduct current in a second direction, opposite to the first direction, thereby contributing to the direct current;
• wherein a resistance of the first switch, when conducting current in the second direction, is adjustable;
• and
• a first modulation unit configured to
• receive the encoded information;
• map the encoded information to a sequence of modulation states from a plurality of different modulation states of the resistance of the first switch;
• wherein each of the plurality of pre-determined modulation states specifies a resistance value and a temporal evolution of the resistance value of the resistance of the first switch;
• adjust the resistance of the first switch according to the sequence of modulation states at a clock rate derived from a cycle rate of the alternating voltage, thereby modulating the current conducted by the first switch according to the sequence of modulation states;
• and
• wherein the first subsystem comprises modulation sensing means configured to detect the sequence of modulation states.

A method for communicating encoded information from a second subsystem to a first subsystem;

• wherein the first and second subsystems are galvanically decoupled;
• the method comprising
• receiving an alternating voltage from the first subsystem at the second subsystem via coupling means;
• blocking current in a first direction and conducting current in a second direction, opposite to the first direction, to provide a direct current;
• wherein the current is conducted in the second direction via an adjustable resistance;
• receiving encoded information;
• mapping the encoded information to a sequence of modulation states from a plurality of different pre-determined modulation states of the adjustable resistance;
• wherein each of the plurality of pre-detennined modulation states specifies a resistance value and/or a temporal evolution of the resistance value of the adjustable resistance;
• and
• adjusting the adjustable resistance according to the sequence of modulation states at a clock rate derived from a cycle rate of the alternating voltage, thereby modulating the conducted current in the second direction according to the sequence of modulation states.