Self-excited power minimizer/maximizer for switching power converters and switching motor drive applications

A controller for controlling a switching electrical circuit, comprising:

• first means for sensing a perturbed waveform of the electrical circuit, wherein the perturbed waveform is perturbed by a switching operation of the electrical circuit;
• second means for sensing a variable to be controlled of the electrical circuit;
• a correlation calculator coupled to the first and second means and operable to compute a correlation output comprising a correlation between the perturbed waveform and the variable to be controlled;
• and
• an operating point generator coupled to the correlation output and to the electrical circuit and operable to change an operating point of the electrical circuit based upon the correlation output.

A method for controlling an input power to a switching dc-dc converter, comprising the steps of:

• (a) sensing a ripple on an input voltage to the converter, wherein the ripple is produced by a switching operation of the converter;
• (b) sensing the input power to the converter;
• (c) computing a correlation between the ripple and the input power;
• and
• (d) varying a duty ratio of the switching operation until the correlation is minimized.

A controller for controlling an input power to a switching dc-dc converter, comprising:

• first means for sensing a ripple on an input voltage to the converter, wherein the ripple is produced by a switching operation of the converter;
• second means for sensing the input power to the converter;
• a correlation calculator coupled to the first and second means and operable to compute a correlation output comprising a correlation between the ripple and the input power;
• and
• a switching driver coupled to the correlation calculator and to the converter and operable to vary a duty ratio of the switching operation based upon the correlation output.

A method for controlling an input power to an ac motor, comprising the steps of:

• (a) sensing a ripple on an input voltage to the ac motor, wherein the ripple is produced by a switching operation of a driver of the ac motor;
• (b) sensing the input power to the ac motor;
• (c) computing a correlation between the ripple and the input power;
• and
• (d) varying a magnetic flux of the ac motor until the correlation is minimized.

A controller for controlling an input power to an ac motor, comprising:

• first means for sensing a ripple on an input voltage to the ac motor, wherein the ripple is produced by a switching operation of a driver of the ac motor;
• second means for sensing the input power to the ac motor;
• a correlation calculator coupled to the fist and second means and operable to compute a correlation output comprising a correlation between the ripple and the input power;
• and
• a motor driver coupled to the correlation calculator and to the ac motor and operable to vary the magnetic flux of the ac motor based upon the correlation output.