Sensorless brushless motor

Claim 2

A sensorless brushless motor as claimed in claim 1, wherein said waveform generating means includes means in which the slant of the slant waveform signals on a time basis can be changed in response to the period of a shaping signal generated by said counter electromotive force detecting means.

Claim 3

A sensorless brushless motor as claimed in claim 1, wherein said waveform generating means comprises counter means which repeats counting and resetting clock signals in response to a shaping signal of said counter electromotive force detecting means; and digital-analog converter means for converting the content of said counter means into an analog value.

Claim 4

A sensorless brushless motor as claimed in claim 1, wherein said waveform generating means includes means for changing the frequency of a clock signal in response to the period of a shaping signal of said counter electromotive force detecting means.

Claim 5

A sensorless brushless motor comprising: three-phase stator windings; counter electromotive force detecting means for generating a shaping signal in response to counter electromotive forces respectively induced in said three-phase stator windings; logical pulse generating means for generating a plurality of pulse signals in response to said shaping signal; first slant waveform generating means for generating a first slant waveform signal in response to said shaping signal; second slant waveform generating means for generating a second slant waveform signal at a different timing from said first slant waveform signal in response to said shaping signal; first position signal forming means for forming first three-phase position signals from the pulse signals of said logical pulse generating means and the first slant waveform signal of said first slant waveform generating means; 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 conducted in response to said first position signals and forms an electric current loop between one terminal of a direct-current power source and the electric current receiving terminals of said stator windings; and a second driving transistors group comprising three transistors, which is controllably conducted in response to said second position signals and forms an electric current loop between the other terminal of said direct-current power source and said electric current receiving terminals thereof.

Claim 6

A sensorless brushless motor as claimed in claim 5, wherein said first slant waveform generating means or said second slant waveform generating means includes means in which the slant of the first slant waveform signal or second slant waveform signal on a time basis can be changed in response to the period of a shaping signal of said counter electromotive force detecting means.

Claim 7

A sensorless brushless motor as claimed in claim 5, wherein said first slant waveform generating means or second slant waveform generating means comprises: counter means which repeats counting and resetting clock signals in response to a shaping signal of said counter electromotive force detecting means; and digital-analog converter means for converting the content of said counter means into an analog value.

Claim 8

A sensorless brushless motor as claimed in claim 7, wherein said first slant waveform generating means or said second slant waveform generating means includes means for changing the frequency of a clock signal in response to the period of a shaping signal of said counter electromotive force detecting means.

Claim 9

A sensorless brushless motor comprising: three-phase stator windings; counter electromotive force detecting means for generating a shaping signal in response to counter electromotive forces respectively induced in said three-phase stator windings; logical pulse generating means for generating a plurality of pulse signals in response to said shaping signal; waveform generating means for generating slant waveform signals whose slants are started from or substantially from the edge points of said shaping signal; signal forming means for forming six-phase formed signals having the rising slant portions and falling slant portions whose lants are started from or substantially from the edge points of said shaping signal from the pulse signals of said logical pulse generating means and the slant waveform signals of said waveform generating means; 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 conducted 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 power source and the electric current receiving terminals of said stator windings; and a second driving transistors group comprising three transistors, which is controllable conducted in response to second three-phase position signals of said signal preparing means and forms an electric current loop between the other terminal of said direct-current power source and said electric current receiving terminals thereof.

Claim 10

A sensorless brushless motor as claimed in claim 9, wherein said waveform generating means includes means in which the slant of a slant waveform signal on a time basis can be changed in response to the period of a shaping signal of said counter electromotive force detecting means.

Claim 11

A sensorless brushless motor as claimed in claim 9, wherein said waveform generating means comprises: counter means which repeats counting and resetting clock signals in response to a shaping signal of said counter electromotive force detecting means; and a digital-analog converter means for converting the content of said counter means into an analog value.

Claim 12

A sensorless brushless motor as claimed in claim 11, wherein said waveform generating means includes means in which the frequency of a clock signal can be changed in response to the period of a shaping signal of said counter electromotive force detecting means.

Claim 13

A sensorless brushless motor as claimed in claim 9, wherein said signal preparing means includes first negative-feedback loop means and second negative-feedback loop means, said first negative-feedback loop means having means for generating first feedback formed signals from the three-phase signals obtained respectively in response to the three-phase formed signals of said signal forming means and means for coinciding said first feedback formed signals with a first command signal, and said second negative-feedback loop means having means for generating second feedback formed signals from the three-phase obtained respectively in response to the other three-phase formed signals of said signal forming means and means for coinciding said second feedback combined signal with a second command signal.

Claim 14

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

Claim 15

A sensorless brushless motor as claimed in claim 6, wherein said first slant waveform generating means or said second waveform generating means includes means for changing the slant of said first slant waveform signal or said second slant waveform signal on a time basis in response to the period of a shaping signal of said counter electromotive force detecting means.

Claim 16

A sensorless brushless motor as claimed in claim 14, wherein said first slant waveform generating means or said second slant waveform generating means comprises: counter means which repeats counting and resetting clock signals in response to a shaping signal of said counter electromotive force detecting means; and digital-analog converter means for converting the content of said counter means into an analog value.

Claim 17

A sensorless brushless motor as claimed in claim 16, wherein said first slant waveform generating means or said second slant waveform generating means includes means for changing the frequency of a clock signal in response to the period of a shaping signal of said counter electromotive force detecting means.

Claim 18

A sensorless brushless motor as claimed in claim 14, wherein said first position signal preparing means includes negative-feedback loop means having means for generating feedback formed signals from the three-phase signals obtained respectively in response to the first three-phase formed signals of said first formed signal forming means and means for coinciding said feedback formed signals with a command signal.

Claim 19

A sensorless brushless motor as claimed in claim 14, wherein said second position preparing means includes negative-feedback loop means having means for generating feedback combined signals from the three-phase signals obtained respectively in response to the second three-phase formed signals of said second formed signal forming means and means for coinciding said feedback formed signals with a command signal.