Low line harmonic AC to DC power supply

A low line current harmonic power supply, adapted to receive power from an AC line, including a predetermined number of phase pairs, wherein the power supply comprises:

• a capacitor disposed in parallel across the output of the power supply;
• means for generating indicia of the phase of each phase pair of the AC line;
• and, for each phase pair:
• a rectifier responsive to the AC line voltage on the phase pair;
• an energy transformation circuit connected between the rectifier for the phase pair and the capacitor;
• a power switch, responsive to a control signal applied thereto, for selectively energizing the energy transformation circuit;
• means, responsive to the indicia of the phase of the phase pair, for synthesizing indicia of a desired input current waveform reference;
• and
• a control circuit, responsive to the indicia of the desired waveform for the phase pair, for generating the control signal to the power switch.

A method of producing a substantially constant output voltage from an AC line without producing substantial line harmonics, comprising the steps of:

• rectifying the voltage across the AC line;
• applying the rectified voltage to an energy transformation circuit;
• applying the output of the energy transformation circuit to an output voltage capacitor;
• and
• controlling the energization of the energy transformation circuit in accordance with a synthesized waveform phase-locked to the voltage waveform of the AC line to draw input current sinusoidally in phase with input voltage.

A method of producing a substantially constant output voltage from a predetermined number of phase pairs without producing substantial line harmonics, comprising the steps of:

• rectifying the voltage across each phase pair;
• applying the rectified voltages from each phase pair to a respective energy transformation circuit associated with the phase pair;
• applying the output of each energy transformation circuit to a common output voltage capacitor;
• and
• controlling the energization of the energy transformation circuit associated with each phase pair in accordance with a synthesized waveform phase-locked to the phase pair to draw input current sinusoidally in phase with the input voltage.

A low line current harmonic apparatus, adapted to receive power from an AC line, the apparatus including:

• a rectifier responsive to the AC line voltage;
• a capacitor disposed in parallel across the output of the power supply;
• an energy transformation circuit interposed between the rectifier and the capacitor;
• a power switch, responsive to a control signal applied thereto, for selectively energizing the energy transformation circuit;
• a control circuit, for executing the basic control algorithm for generating the control signal to the power switch;
• the apparatus characterized in that:
• the apparatus includes a means, phase-locked to the voltage waveform of the AC line, for synthesizing indicia of a desired input current waveform reference;
• and
• the control signal to the power switch is derived, at least in part, from the indicia of the desired waveform.

A low line current harmonic apparatus, adapted to receive power from an AC line, including a predetermined number of phase pairs, wherein the apparatus comprises:

• a capacitor disposed in parallel across the output of the power supply;
• means for generating indicia of the phase of each phase pair of the AC line;
• and, for each phase pair:
• a rectifier responsive to the AC line voltage on the phase pair;
• an energy transformation circuit connected between the rectifier for the phase pair and the capacitor;
• a power switch, responsive to a control signal applied thereto, for selectively energizing the energy transformation circuit;
• means, responsive to the indicia of the phase of the phase pair, for synthesizing indicia of a desired input current waveform reference;
• and
• a control circuit, for executing the basic control algorithm, which is responsive to the indicia of the desired waveform for the phase pair, for generating the control signal to the power switch.

A method of producing a substantially constant output voltage from an AC line without producing substantial line harmonics, comprising the steps of:

• rectifying the voltage across the AC line;
• applying the rectified voltage to an energy transformation circuit;
• applying the output of the energy transformation circuit to an output voltage capacitor;
• and
• controlling the energization of the energy transformation circuit in accordance with the basic control algorithm, phase-locked to the voltage waveform of the AC line to draw input current sinusoidally in phase with input voltage.

A method of producing a substantially constant output voltage from a predetermined number of phase pairs without producing substantial line harmonics, comprising the steps of:

• rectifying the voltage across each phase pair;
• applying the rectified voltages from each phase pair to a respective energy transformation circuit associated with the phase pair;
• applying the output of each energy transformation circuit to a common output voltage capacitor;
• and
• controlling the energization of the energy transformation circuit associated with each phase pair in accordance with the basic control algorithm, phase-locked to the phase pair to draw input current sinusoidally in phase with the input voltage.