Sensorless brushless motor

A sensor less brushless motor comprising:

• three-phase stator windings;
• a counter electrocute force detecting means for generating a shaping signal in response to counter electromotive forces respectively induced in said three-phase stator windings;
• a logical pulse generating means for generating a plurality of pulse signals in response to said shaping signal;
• a first slant waveform generating means for generating a first slant waveform signal in response to said shaping
• a second slant waveform generating means for generating a second slant waveform signal at a different timing fro said first slant waveform signal in response to said shaping signal;
• a first position signal forming means for forming first three-phase position signals fro the pulse signals of said logical pulse generating means and the first slant waveform signal of said first slant waveform generating means;
• a second position signal forming means for forming second three-phase position signals having different timings from those of said first position signals from the pulse signals of said logical pulse generating means and the second slant waveform signal of said second slant waveform generating means;
• a first driving transistors group comprising three transistors, which is controllably caused to conduct in response to said first position signals and forms an electric current loop between on terminal of a direct-current power source and electric current receiving terminals of said stator windings;
• and
• a second driving transistors group comprising three transistors, which is controllably caused to conduct in response to said second position signals and forms an electric current loop between another terminal of said direct-current power source and said electric current receiving terminals of said stator windings.

A sensorless brushless motor comprising:

• three-phase stator windings;
• a counter electromotive force detecting means for generating a shaping signal in response to counter electromotive forces respectively induced in said three-phase stator windings;
• a logical pulse generating means for generating a plurality of pulse signals in response to said shaping signal;
• a waveform generating means for generating slant waveform generating means for generating slant waveform signals whose slants are started form or substantially from the edge points of said shaping signal
• a signal forming means for forming six-phase formed signals having rising slant portions and falling slant portions whose slants are started from or substantially from the edge points of said shaping signal fro the pulse signals of said logical pulse generating means and the slant waveform signals of said waveform generating means;
• a signal preparing means for preparing six-phase trapezoidal waveform position signals respectively in response to said six-phase formed signals;
• a first driving transistors group comprising three transistors, which is controllably caused to conduct in response to first three-phase position signals outputted from said signal preparing means and forms an electric current loop between one terminal of a direct-current owner source and electric current receiving terminals of said stator windings;
• and
• a second driving transistors group comprising three transistors which is controllable caused to conduct in response to second three-phase position signals of said signal preparing means and forms an electric current loop between another terminal of said direct-current power source and said electric current receiving terminals of said stator windings.

A sensorless brushless motor comprising:

• three-phase stator windings;
• a counter electromotive force detecting means for generating a shaping signal in response to counter electromotive forces respectively induced in said stator windings;
• a logical pulse generating means for generating a plurality of pulse signals in response to aid shaping signal;
• a first slant waveform generating means for generating a first slant waveform signal in response to said shaping signal;
• a second slant waveform generating means for generating a second slant waveform signal at a different timing from said shaping signal;
• a first formed signal forming means for generating first three-phase formed signals fro the pulse signals of said logical pulse generating means and the first slant waveform signal of said first slant waveform generating means in such a conduction that the rising and falling slant portions of said first three-phase formed signals are stared at a timing equal or substantially equal to that of said first slant waveform signal;
• a second formed signal forming means for generating second three-phase formed signals from the pulse signals of said logical pulse generating means and the second slant waveform signal of said second slant waveform generating means in such a condition that the rising and falling slant portions of said second three-phase formed signals are started at a timing equal or substantially equal to that of said second slant waveform signal;
• a first portion signal preparing means for preparing first three-phase position signals of a trapezoidal waveform respectively in response to said first three-phase formed signals;
• a second position signal preparing means for preparing second three-phase position signals of a trapezoidal waveform respectively in response to said second three-phase formed signals;
• a first driving transistors group comprising three transistors, which is controllably caused to conduct in response to said first three-phase position signals and forms an electric current loop between one terminal of a direct-current power source and electric current receiving terminals of said stator windings;
• and
• a second driving transistors group comprising three transistors, which is controllably caused to conduct in response to said second three-phase position signals and forms an electric current loop between another terminal of said direct-current power source and said electric current receiving terminals of said stator windings.