System and method for input current shaping in a power converter

A boost-type AC to DC power converter, comprising:

• a boost power stage for transferring electrical power received in the form of an AC input voltage signal from a power source to a load;
• a switch in the power stage that electrically couples or decouples the load to or from the power source;
• and
• a switch controller coupled to the switch for shaping input current to the power converter based upon a first reference shape of peak current values and a second reference shape of peak off-time values, wherein the switch controller:
• determines a count corresponding to a phase of the AC input voltage signal, the count corresponding to one of at least a first range, a second range, and a third range of the phase of the input voltage signal;
• determines turn-on timings and turn-off timings of the switch based upon one or more operation modes, at least one of the operation modes being a peak current switching mode that determines the turn-off timings of the switch so as to keep the switch on until a current through the switch reaches the peak current value corresponding to the determined count at which time the switch is turned off, and at least another one of the operation modes being a shaped off-time switching mode that determines the turn-on timings of the switch so as to keep the switch off until a duration of the off-time of the switch reaches the peak off-time value corresponding to the count at which time the switch is turned on;
• and
• controls the switch to be turned on and off based upon the determined turn-on timings and the determined turn-off timings, respectively.

A controller for shaping an input current to a boost-type AC to DC power converter, the power converter including a boost power stage for transferring electrical power from a power source to a load and a switch in the boost power stage that is controlled by the controller and electrically couples or decouples the load to or from the power source, the controller comprising:

• a current shaper module for determining waveform synthesis parameters based upon an AC input voltage signal and a first reference shape of peak current values and a second reference shape of peak off-time values, and for determining a count corresponding to a phase of the AC input voltage signal, the count corresponding to one of at least a first range, a second range, and a third range of the phase of the input voltage signal;
• an operation mode selector module receiving the waveform synthesis parameters and the count, and selecting at least one of a plurality of operation modes configured to determine turn-on timings and turn-off timings of the switch, at least one of the operation modes being a peak current switching mode configured to determine the turn-off timings of the switch so as to keep the switch on until a current through the switch reaches the peak current value corresponding to the determined count at which time the switch is turned off, and at least another one of the operation modes being a shaped off-time switching mode configured to determine the turn-on timings of the switch so as to keep the switch off until a duration of the off-time of the switch reaches the peak off-time value corresponding to the count at which time the switch is turned on;
• and
• a current waveform synthesizer module determining the turn-on timings and turn-off timings of the switch based upon the selected operation mode and for controlling the switch in accordance with the determined turn-off timings and the determined turn-on timings of the switch, respectively.

A controller for shaping an input current to a boost-type AC to DC power converter based upon a first reference shape of peak current values and a second reference shape of peak off-time values, the power converter including a boost power stage for transferring electrical power received in a form of input voltage signal from a power source to a load, and a switch in the power stage that is controlled by the controller and electrically couples or decouples the load to or from the power source, wherein the controller:

• determines a count corresponding to a phase of the AC input voltage signal, the count corresponding to one of at least a first range, a second range, and a third range of the phase of the input voltage signal;
• determines turn-on timings and turn-off timings of the switch based upon one or more operation modes, at least one of the operation modes being a peak current switching mode that determines the turn-off timings of the switch so as to keep the switch on until a current through the switch reaches the peak current value corresponding to the determined count at which time the switch is turned off, and at least another one of the operation modes being a shaped off-time switching mode that determines the turn-on timings of the switch so as to keep the switch off until a duration of the off-time of the switch reaches the peak off-time value corresponding to the count at which time the switch is turned on;
• and
• controls the switch to be turned on and off based upon the determined turn-on timings and the determined turn-off timings, respectively.