US 11,888,419 B2 · Unified open-circuit fault-tolerant control method for vector control drive system and direct torque control drive system of five-phase permanent magnet fault tolerant motor

Abstract

A unified open-circuit fault-tolerant control method for a vector control (VC) drive system and a direct torque control (DTC) drive system of a five-phase permanent magnet fault-tolerant motor are provided. The control method adopts a unified open-circuit fault-tolerant control strategy. The unified open-circuit fault-tolerant control strategy includes: obtaining a predetermined torque, obtaining predetermined direct-axis and quadrature-axis voltages, analyzing a fault-tolerant mechanism to obtain fault-tolerant currents, obtaining winding phase voltages in a fault mode based on the fault-tolerant mechanism, and obtaining fault-tolerant voltages based on a back-electromagnetic force (EMF). The unified open-circuit fault-tolerant control strategy suitable for the VC drive system and the DTC drive system is proposed based on chaotic pulse width modulation (CPWM). The control method essentially reveals the fault-tolerant mechanism, and solves the problem of variable and complicated fault-tolerant control schemes corresponding to various basic control algorithms.

step 1) establishing a mathematical model of various currents of the five-phase permanent magnet fault-tolerant motor under normal operation:
wherein currents iA, iB, iC, iD, and iE of the five-phase permanent magnet fault-tolerant motor under normal operation are as follows:
[
i
A
i
B
i
C
i
D
i
E
]
=
[
sin
⁢
θ
cos
⁢
θ
sin
⁢
3
⁢
θ
cos
⁢
3
⁢
θ
sin
⁢
(
θ
-
γ
)
cos
⁢
(
θ
-
γ
)
sin
⁢
3
⁢
(
θ
-
γ
)
cos
⁢
3
⁢
(
θ
-
γ
)
sin
⁢
(
θ
-
2
⁢
γ
)
cos
⁢
(
θ
-
2
⁢
γ
)
sin
⁢
3
⁢
(
θ
-
2
⁢
γ
)
cos
⁢
3
⁢
(
θ
-
2
⁢
γ
)
sin
⁢
(
θ
-
3
⁢
γ
)
cos
⁢
(
θ
-
3
⁢
γ
)
sin
⁢
3
⁢
(
θ
-
3
⁢
γ
)
cos
⁢
3
⁢
(
θ
-
3
⁢
γ
)
sin
⁢
(
θ
-
4
⁢
γ
)
cos
⁢
(
θ
-
4
⁢
γ
)
sin
⁢
3
⁢
(
θ
-
4
⁢
γ
)
cos
⁢
3
⁢
(
θ
-
4
⁢
γ
)
]
[
i
d
⁢
1
*
i
q
⁢
1
*
i
d
⁢
3
*
i
q
⁢
3
*
]
wherein, γ=72°;
θ is an electrical angle of a rotor position;
id1* and iq1* are direct-axis and quadrature-axis components of a predetermined value of a fundamental current;
and id3* and iq3* are direct-axis and quadrature-axis components of a predetermined value of a third harmonic current;
step 2) obtaining fault-tolerant currents under an open circuit of a single phase, open circuits of two non-adjacent phases and open circuits of two adjacent phases, and analyzing a fault-tolerant mechanism;
step 3) constructing a torque controller based on a difference between a predetermined speed and a detected speed to obtain a predetermined torque Te* to suppress a torque ripple of the motor after a fault, wherein a load disturbance, system parameter changes, and an electromagnetic torque ripple caused by the fault are considered;
step 4) detecting the five-phase currents iA, iB, iC, iD, and iE of the five-phase permanent magnet fault-tolerant motor, and obtaining current components id1, iq1, id3, and iq3 in a two-phase rotating coordinate system through Clark and Park transforms;
wherein, the current components of the five-phase permanent magnet fault-tolerant motor in the two-phase rotating coordinate system are expressed as follows:
[
i
d
⁢
1
i
q
⁢
1
i
d
⁢
3
i
q
⁢
3
]
=
[
cos
⁢
θ
cos
⁢
(
θ
-
γ
)
cos
⁢
(
θ
-
2
⁢
γ
)
cos
⁢
(
θ
-
3
⁢
γ
)
cos
⁢
(
θ
-
4
⁢
γ
)
-
sin
⁢
θ
-
sin
⁢
(
θ
-
γ
)
-
sin
⁢
(
θ
-
2
⁢
γ
)
-
sin
⁢
(
θ
-
3
⁢
γ
)
-
sin
⁢
(
θ
-
4
⁢
γ
)
cos
⁢
3
⁢
θ
cos
⁢
3
⁢
(
θ
-
γ
)
cos
⁢
3
⁢
(
θ
-
2
⁢
γ
)
cos
⁢
3
⁢
(
θ
-
3
⁢
γ
)
cos
⁢
3
⁢
(
θ
-
4
⁢
γ
)
-
sin
⁢
3
⁢
θ
-
sin
⁢
3
⁢
(
θ
-
γ
)
-
sin
⁢
3
⁢
(
θ
-
2
⁢
γ
)
-
s
⁢
in
⁢
3
⁢
(
θ
-
3
⁢
γ
)
-
sin
⁢
3
⁢
(
θ
-
4
⁢
γ
)
]
[
i
A
i
B
i
C
i
D
i
E
]
step 5) calculating direct-axis and quadrature-axis fundamental voltages of the VC drive system and the DTC drive system based on the current components id1 and iq1 in the two-phase rotating coordinate system and the predetermined torque Te*;
step 6) obtaining direct-axis and quadrature-axis third harmonic voltages through the current components id3 and iq3 in the two-phase rotating coordinate system, based on a control strategy of zero third harmonic current;
step 7) calculating winding phase voltages in a fault mode based on the fault-tolerant mechanism and the direct-axis and quadrature-axis voltages;
step 8) obtaining predetermined phase voltages in a fault-tolerant operation mode based on a back-electromotive force (EMF) and the winding phase voltages in the fault mode;
and
step 9) processing the predetermined phase voltages by a voltage source inverter, and achieving undisturbed operation of the VC drive system and the DTC drive system of the five-phase permanent magnet fault-tolerant motor under open-circuit fault through chaotic pulse width modulation (CPWM).

431 more elements

Unified open-circuit fault-tolerant control method for vector control drive system and direct torque control drive system of five-phase permanent magnet fault tolerant motor

Life of this patent

Unified open-circuit fault-tolerant control method for vector control drive system and direct torque control drive system of five-phase permanent magnet fault tolerant motor

Life of this patent

Abstract

Claims9