Finite time speed control method for permanent magnet synchronous motor based on fast integral terminal sliding mode and disturbance estimation

Patent metadata

Field	Value
Publication number	US-12088224-B2
Application number	US-202117640216-A
Country	US
Kind code	B2
Filing date	May 6, 2021
Priority date	May 6, 2021
Publication date	Sep 10, 2024
Grant date	Sep 10, 2024

Abstract

A finite time speed control method for a permanent magnet synchronous motor (PMSM) based on a fast integral terminal sliding mode and disturbance estimation comprises: firstly, determining a mathematical model of a speed loop of the PMSM under the influence of system parameters uncertainty and unknown load torque; secondly, designing an improved fast integral terminal sliding surface on the basis of the idea of terminal sliding mode control; then, proposing a disturbance estimation method based on an adaptive fuzzy system with respect to the disturbance in a PMSM system; designing a PMSM speed controller on this basis; and finally, completing the concrete implementation of the whole technical solution. The present invention designs the fast integral terminal sliding surface and a sliding mode control law to ensure that a motor speed tracking error converges to zero within finite time and enhances the rapidity of a PMSM speed regulating system.

First claim

The invention claimed is:

1. A finite time speed control method for a permanent magnet synchronous motor (PMSM) based on a fast integral terminal sliding mode and disturbance estimation, comprising the following steps:
S1: determining a mathematical model of a speed loop of the PMSM under a influence of system parameters uncertainty and unknown load torque;
in a d−q coordinate system, a mathematical model of a speed loop of a non-salient pole permanent magnet synchronous motor is:

ω
.

=

K
t

J

⁢

i
q

-

B
J

⁢
ω

-

T
L

J

where ω is motor speed; i q represents stator current of q axis; K t is a torque constant; J represents a moment of inertia; B is a viscous friction coefficient; and T L represents a load torque;
considering the influence of system parameters uncertainty, unknown load torque and current loop tracking error, the mathematical model of the speed loop of the PMSM is:

ω
.

=

K
t

J
n

⁢

i
q
*

-

B
o

+

Δ
⁢
B

J
n

+

Δ
⁢
J

⁢
ω

+

(

K
t

J

-

K
t

J
n

)

⁢

i
q

-

T
L

J

+

K
t

J
n

⁢

(

i
q

-

i
q
*

)

in a formula, B o and J n represent nominal values of a viscous friction coefficient and the moment of inertia respectively; ΔB=B−B o and ΔJ=J−J n represent deviations between true values and the nominal values of the viscous friction coefficient and the moment of inertia; i q * represents a reference value of the stator current of the q axis, a PMSM speed controller to be designed;
after processing the mathematical model of the speed loop of the PMSM which considers the system disturbance, obtaining:
{dot over (ω)}= ai q *+d

in the formula, d(t) represents a lumped disturbance term; α is a known constant coefficient;
S2: constructing a fast integral terminal sliding surface:
firstly, defining a speed tracking error: e=ω−ω d , where ω d represents motor target speed;

then, designing the fast integral terminal sliding surface as: s=e+α∫ 0 t edσ+β∫ 0 t e q/p dσ; where α, β>0 which are constant coefficients; 0<q/p<1; and q and p are positive odd numbers;
when the tracking error of the motor speed converges to a sliding surface, s=0,
e=−α∫ 0 t edσ−β∫ 0 t e q/p dσ;

solving a above equation to obtain time for a tracking error of the motor speed to converge to zero from reaching the sliding surface:

t
s

=

p

α
⁡
(

p
-
q

)

⁢

(

ln
[

α
⁢

e
⁡
(
0
)

(

p
-
q

)

/
p

+
β

]

-

ln
⁢

β

)

Assignees

• Univ Dalian Tech

Inventors

• Sun Ximing
• Zhang Jianyi

Classifications

• H02P2207/05

  Synchronous machines, e.g. with permanent magnets or DC excitation · CPC title

• H02P25/022 Primary

  Synchronous motors (H02P25/064 takes precedence) · CPC title

• H02P21/18

  Estimation of position or speed · CPC title

• H02P21/14

  Estimation or adaptation of machine parameters, e.g. flux, current or voltage · CPC title

• H02P21/001

  using fuzzy control · CPC title