Motor Driving Apparatus

Abstract

A motor having plural-phase windings and a rotor includes a position detector, a state determining device, an activation controlling device, and a switching controlling device. The position detecting device detects the position of the rotor according to a comparison signal obtained by comparing terminal voltages of the windings in a non-activation phase with a center tap voltage of a common potential of the plural-phase windings and outputting a position detection signal. The state determining device detects the state of the rotor and outputs the result obtained by comparing the position detection signal with a predetermined value. The activation controlling device performs activation control of the windings by setting a leading phase of an activation control signal with respect to the position detection signal when the state determining device outputs a first output signal, and performs activation control of the windings by canceling the leading phase of an activation control signal with respect to the position detection signal when the state determining device outputs a second output signal. The switching controlling device outputs a drive signal for performing high-frequency switching control according to a command signal to the activation controlling device.

1 . A motor having plural-phase windings and a rotor, the motor comprising: 
 a position detecting means for detecting position of said rotor according to a comparison signal obtained by comparing terminal voltages of said windings in a non-activation phase with a center tap voltage of a common potential of said plural-phase windings and outputting a position detection signal;    a state determining means for detecting the state of said rotor, and outputting the result obtained by comparing the position detection signal with a predetermined value;    an activation controlling means for performing activation control of said windings by setting a leading phase of an activation control signal with respect to said position detection signal when said state determining means outputs a first output signal, and performing activation control of said windings by canceling leading the leading phase of an activation control signal with respect to said position detection signal when said state determining means outputs a second output signal; and    a switching controlling means for outputting a drive signal for performing high-frequency switching control according to a command signal to said activation controlling means.    
   
   
       2 . The motor in accordance with  claim 1 , wherein said state determining means determines whether or not a rotor rotating speed obtained on the basis of said position detection signal exceeds a predetermined value.  
   
   
       3 . The motor in accordance with  claim 1 , wherein said state determining means determines whether or not an electrical cycle of said activation control signal is output a predetermined number of time or more.  
   
   
       4 . The motor in accordance with  claim 1 , wherein said activation controlling means cancels the leading phase linearly or gradually according to an output of said state determining means.  
   
   
       5 . The motor in accordance with  claim 1 , wherein said activation controlling means set a second leading phase smaller than the leading phase of said activation control signal with respect to said position detection signal when said state determining means outputs the first output signal, and the leading phase is canceled when said state determining means outputs the second output signal, and activation control in the second leading phase is performed.  
   
   
       6 . The motor in accordance with  claim 1 , wherein said switching controlling means performs slope control and the waveform of a driving current flowing to said plural-phase windings forms a trapezoidal wave, the trapezoidal wave having a slope control angle at a rising side of a slope and a slope control angle at a falling side of a slope.  
   
   
       7 . The motor in accordance with  claim 6 , wherein said activation controlling means sets the leading phase by controlling the slope control angles of substantially trapezoidal waveform of a current flowing to said plural-phase windings at rising and falling sides of a slope, respectively, when said state determining means outputs the first output signal.  
   
   
       8 . The motor in accordance with  claim 6 , wherein said activation controlling means sets leading phase by reducing a slope control angle of a substantially trapezoidal waveform of a current flowing to said plural-phase windings when said state determining means outputs the first output signal.