Position detecting device and synchronous motor driving device using the same

Abstract

A position detecting device which can increase accuracy in detecting the pole position of a motor used to perform quick acceleration and deceleration over the range from a zero speed to a high rotation speed, and a synchronous motor driving device using the position detecting device. A position detector detects basic-wave component signals in sensor signals and executes position calculation. A correcting unit calculates signal information representing at least one of a gain, an offset and a phase by a phase detector from the basic-wave component signals detected by an error calculator, and makes correction based on the calculated signal information such that a position detection error is zero.

1 . A position detecting device for detecting a motor pole position by using two or more sensor signals, said position detecting device comprising: 
 a position detector for detecting basic-wave component signals in said sensor signals and executing position calculation; and    correcting means for calculating signal information representing at least one of a gain, an offset and a phase from the detected basic-wave component signals, and making correction based on the calculated signal information such that a position detection error is zero.    
   
   
       2 . The position detecting device according to  claim 1 , wherein said position detector extracts said sensor signals in a range between predetermined first and second determination values, thereby detecting said basic-wave component signals.  
   
   
       3 . The position detecting device according to  claim 1 , wherein said position detector extracts sensor signals representing middle potentials of said sensor signals, thereby detecting said basic-wave component signals.  
   
   
       4 . The position detecting device according to  claim 1 , wherein said sensor signal has a distorted waveform including a predetermined zone in which a sensor signal value is hardly changed.  
   
   
       5 . The position detecting device according to  claim 1 , wherein said sensor signals are three-phase signals of U-, V- and W-phases, and 
 said position detector extracts a signal from a cross point between the U-phase signal and the W-phase signal to a cross point between the V-phase signal and the W-phase, a signal from a cross point between the V-phase signal and the W-phase signal to a cross point between the U-phase signal and the V-phase, and a signal from a cross point between the U-phase signal and the V-phase signal to a cross point between the U-phase signal and the W-phase, thereby detecting said basic-wave component signals.    
   
   
       6 . The position detecting device according to  claim 1 , wherein said correcting means comprises: 
 an error calculator for calculating a position error amount from a position calculated value obtained by said position detector; and    a position corrector for correcting the position calculated value by using the position error amount calculated by said error calculator.    
   
   
       7 . The position detecting device according to  claim 1 , wherein said correcting means includes a signal corrector for determining an error amount of said sensor signal from a difference between said signal information and a predetermined reference value, and for correcting the sensor signal such that the determined error amount is zero.  
   
   
       8 . The position detecting device according to  claim 1 , further comprising a sensor unit for generating said sensor signal, 
 wherein said sensor unit includes a magnetic adjusting member for adjusting an amount of effective magnetic flux crossing a sensor.    
   
   
       9 . The position detecting device according to  claim 1 , further comprising a sensor unit for generating said sensor signal, 
 wherein said sensor unit includes a magnetic shielding member oriented perpendicularly to a direction in which a sensor senses magnetic flux.    
   
   
       10 . The position detecting device according to  claim 1 , further comprising a sensor unit for generating said sensor signal, 
 wherein said sensor unit includes a plurality of sensors attachable to a motor housing from the outside.    
   
   
       11 . A position detecting device for detecting a motor pole position by using two or more sensor signals, said position detecting device comprising: 
 a position detector for detecting basic-wave component signals in said sensor signals and executing position calculation; and    correcting means for calculating signal information representing at least one of a gain, an offset and a phase from the detected basic-wave component signals, and making correction based on the calculated signal information such that a position detection error is zero,    wherein said position detector extracts said sensor signals in a range between predetermined first and second determination values, thereby detecting said basic-wave component signals.    
   
   
       12 . A permanent-magnet synchronous motor driving device comprising: 
 a position detecting device for detecting a motor pole position by using two or more sensor signals; and    a motor controller for producing a PWM drive signal based on a position detected value detected by said position detecting device, and outputting the PWM drive signal to an inverter, thereby driving a permanent-magnet synchronous motor,    wherein said position detecting device comprises:    a position detector for detecting basic-wave component signals in said sensor signals and executing position calculation; and    correcting means for calculating signal information representing at least one of a gain, an offset and a phase from the detected basic-wave component signals, and making correction based on the calculated signal information such that a position detection error is zero.    
   
   
       13 . The permanent-magnet synchronous motor driving device according to  claim 12 , wherein said motor controller includes a rotor position settling unit for driving said permanent-magnet synchronous motor through a predetermined electrical angle in a stepping manner under PWM control and settling a rotor stop position of said motor when the signal information is calculated by said correcting means, and 
 said correcting means of said position detecting device calculates, at a rotor position settled by said rotor position settling unit, a rotor position detection error from a difference between a value of the settled rotor position and the position detected value detected by said position detecting device,    said rotor position detection error being corrected.    
   
   
       14 . The permanent-magnet synchronous motor driving device according to  claim 12 , wherein said motor controller receives a torque command, and 
 said permanent-magnet synchronous motor has a motive power load over a wide speed range from a stopped state to a state of large acceleration and deceleration.    
   
   
       15 . The permanent-magnet synchronous motor driving device according to  claim 12 , wherein said motor controller receives a torque command from a vehicular control unit, and 
 said permanent-magnet synchronous motor has a vehicular motive power load over a wide speed range from a stopped state to a high-speed travel state.