Direct locating method for calculating position of permanent magnet synchronous motor

A direct locating method for calculating a position of a permanent magnet synchronous motor (PMSM), comprising the following steps performed by a processor:

• step 1:
• converting three-phase stator currents of the PMSM sampled at each period to obtain the stator currents in αβ two-phase stationary coordinate system, and determining an initial position region of the PMSM according to the stator currents in the αβ two-phase stationary coordinate system;
• step 2:
• converting the stator currents of the PMSM in the αβ two-phase stationary coordinate system to obtain the stator current of the PMSM in the dq two-phase synchronous rotation coordinate system;
• step 3:
• establishing the stator current cost model of the permanent magnet synchronous motor, and inputting the d-axis stator current of the permanent magnet synchronous motor in the dq two-phase synchronous rotation coordinate system into the stator current cost model and then the position of the permanent magnet synchronous motor is outputted;
• at the same time, determining a final estimated position from the initial position region of the PMSM according to the stator currents of PMSM in the αβ two-phase stationary coordinate system and dq two-phase synchronous rotation coordinate system, and the direct locating of the PMSM position is realized,
• wherein in step 3, the stator current cost model of the permanent magnet synchronous motor is established as follows:
• min
• ⁢
• g
• op
• (
• k
• )
• =
• ❘
• "\[LeftBracketingBar]"
• i
• dref
• (
• k
• )
• -
• i
• d
• (
• k
• )
• ❘
• "\[RightBracketingBar]"
• ⁢
• i
• d
• (
• k
• )
• =
• A
• ⁢
• sin
• ⁡
• (
• θ
• +
• φ
• k
• )
• ⁢
• i
• q
• (
• k
• )
• =
• A
• ⁢
• sin
• ⁡
• (
• θ
• +
• φ
• k
• +
• π
• /
• 2
• )
• where gop(k) is the d-axis stator current error of the permanent magnet synchronous motor at the kth sampling period in the dq two-phase synchronous rotation coordinate system;
• idref(k) is the d-axis stator current reference of the permanent magnet synchronous motor at the kth sampling period in the dq two-phase synchronous rotation coordinate system;
• id(k) and iq(k) are the d-axis stator current and q-axis stator current of a permanent magnet synchronous motor in dq two-phase synchronous rotation coordinate system at the kth sampling period, respectively;
• θ is the position of the permanent magnet synchronous motor;
• A is the stator current amplitude of the permanent magnet synchronous motor;
• φk is the Angle between the stator current of the permanent magnet synchronous motor and the αβ two-phase stationary coordinate system at the kth sampling period,
• wherein an angle between the stator current of the permanent magnet synchronous motor and the αβ two-phase stationary coordinate system at the kth sampling period, φk, is as follows:
• φ
• k
• =
• arc
• ⁢
• tan
• ⁡
• (
• i
• α
• (
• k
• )
• /
• i
• β
• (
• k
• )
• )
• where iα(k) and iβ(k) are the α-axis stator current and β-axis stator current of the permanent magnet synchronous motor in the αβ two-phase stationary coordinate system at the kth sampling period, respectively,
• wherein in step 3, according to the stator currents of the permanent magnet synchronous motor in the αβ two-phase stationary coordinate system and dq two-phase synchronous rotating coordinate system, the final estimated position is determined in the initial position region of the permanent magnet synchronous motor, as follows:
• Region
• iα
• iβ
• iq
• θo1
• R1
• +
• +
• +
• 2π-φk
• −
• π-φk
• R2
• −
• +
• +
• 2π-φk
• −
• 3π-φk
• R3
• −
• −
• +
• 2π-φk
• −
• 3π-φk
• R4
• +
• −
• +
• 2π-φk
• −
• π-φk
• where θo1 is the final estimated position of the permanent magnet synchronous motor in the initial rotor position region.