US 2013/0253755 A1 · SLIP RATE DETECTION METHOD AND DETECTION SYSTEM FOR ELECTRIC VEHICLE

Abstract

A slip rate detection method and a detection system for detecting the slip rate of an electric vehicle using the method. The slip rate of an electric vehicle is measured by measuring the motor voltage, motor current, and motor rotational speed of the drive motor. The detection system includes a motor rotational speed detection unit, a motor voltage detection unit, and a motor current detection unit, all connected to the drive motor. The motor rotational speed detection unit, the motor voltage detection unit, and the motor current detection unit are connected to a slip rate calculation unit by means of a motor rotational speed signal processing unit, a voltage signal processing unit, and a current signal processing unit, respectively. The slip rate calculation unit is configured with a slip rate calculation formula. The formula is determined according to the drive motor type.

Claims18

Dependent claims

A slip rate detection method for a DC motor driven electric vehicle, comprising the steps of:

(1) measuring voltage, current and rotational speed of a drive motor to obtain armature voltage Ua, armature current ia, and motor rotational speed ωm of said drive motor;
(2) obtaining motor coefficients of said drive motor, including motor inductance La, armature resistance Ra, motor torque coefficient km, and motor back electromotive force coefficient ke;
(3) obtaining full vehicle constants, including full vehicle mass M, wheel radius r, wheel rotational inertia J, and transmission ratio a;
and
(4) obtaining slip rate according to a slip rate calculation formula as shown below:
λ

(
t
2
)
=
(
1
+
J
r
2

M
)
[
1
-
ω
m

(
t
1
)
ω
m

(
t
2
)
]
-
a
2
·
k
m
r
2

MR
a

ω
m

(
t
2
)

{
∫
t


1
t


2

U
a


t
-
k
e

∫
t


1
t


2

ω
m


t
-
L
a
·
[
i
a

(
t
2
)
-
i
a

(
t
1
)
]
}
+
λ

(
t
1
)

ω
m

(
t
1
)
ω
m

(
t
2
)
wherein, t1 is a first measurement time;
t2 is a second measurement time;
and λ is slip rate.

138 more elements

A slip rate detection method for an electric vehicle driven by a permanent magnet synchronous motor, comprising the steps of:

(1) measuring voltage, current, and rotational speed of a drive motor, to obtain motor rotational speed ωm, as well as voltage uq of said drive motor in a dq coordinate system, and armature current iq of said drive motor in said dq coordinate system;
(2) obtaining motor coefficients of said drive motor, including components Ld and Lq of stator inductance of said drive motor in said dq coordinate system, said stator resistance Rs of said drive motor, flux linkage ψf generated by a permanent magnet of said drive motor, and the number of pole pairs np of said drive motor;
(3) obtaining full vehicle constants, including mass M, wheel radius r, wheel rotational inertia J, and transmission ratio a;
and
(4) calculating slip rate according to a slip rate calculation formula as shown below:
λ

(
t
2
)
=
(
1
+
J
r
2

M
)
[
1
-
ω
m

(
t
1
)
ω
m

(
t
2
)
]
-
a
2
·
k
m


1
r
2

MR
s

ω
m

(
t
2
)

{
∫
t


1
t


2

u
q


t
-
ψ
f

∫
t


1
t


2

ω
m


t
-
L
q
·
[
i
q

(
t
2
)
-
i
q

(
t
1
)
]
}
+
λ

(
t
1
)

ω
m

(
t
1
)
ω
m

(
t
2
)
wherein, km1=np[ψf+(Ld−Lq);
t1 is a first measurement time;
t2 is a second measurement time;
and λ is slip rate.

142 more elements

Dependencies are inferred from the claim text.

Slip rate detection method and detection system for electric vehicle

Life of this patent

Slip rate detection method and detection system for electric vehicle

Life of this patent

Abstract

Claims18