Measurement of quadrature axis and direct axis inductance of three-phase permanent magnet synchronous motor

Take the motor as an example

One 、 measuring method
1、 Motor's V Phase and W Join together
2、LCR One probe of the meter is connected to the motor U phase
3、LCR The other lead of the meter is connected to the motor V Phase and W Linked nodes
As shown in the figure

Two 、 Theoretical calculation
take V、W The wires extending from the two windings are connected in parallel , Form a new endpoint , use LCR Table measures this endpoint and U Inductance between the ends of the phase winding .
At this time because ：

 

B Phase winding and C Phase windings are connected in parallel , Have the same flux linkage , So just calculate B Flux linkage of phase winding ：

 

Then the total flux linkage is ：

 

Then the equivalent inductance is ：

 

When θ=0 when

 

When θ=±π/2 when

 

so , When we measure the inductance at the appropriate position of the rotor , You can get d Shaft inductance and q Shaft inductance . But one difficulty of this method is how to know the position of the rotor at this time , An approximate measurement is to rotate the rotor slowly , Write down the maximum and minimum inductance , here ：

 

  3、 ... and 、 Data records
1、 When θ=0 when -- That is, to the motor U Phase power supply ,VW Phase to ground , The motor will automatically make θ=0, Then cut off the electricity , use LCR Table measurement , Wait for the data to stabilize
As shown in the figure ：

 

  The direct axis inductance is 197.07uH

2、 Turn the rotor slowly to find the maximum inductance , Wait a few seconds for it to stabilize  
As shown in the figure

 

Quadrature axis inductance is ：214.73uH