US 2026/0100579 A1 · MICROGRID DISTRIBUTED SECONDARY CONTROL METHOD AND SYSTEM BASED ON VIRTUAL SYNCHRONOUS MACHINE

Abstract

A microgrid distributed secondary control method and system based on a virtual synchronous machine is applied to the technical field of microgrid control. The microgrid distributed secondary control method includes: designing a microgrid primary control strategy based on the virtual synchronous machine, and establishing a microgrid distributed secondary control model based on the virtual synchronous machine by combining a speed regulator equation of the virtual synchronous machine; considering nonlinear characteristics of the virtual synchronous machine, based on a deterministic equivalence principle, designing a linearized microgrid distributed secondary control strategy based on the virtual synchronous machine; and based on the deterministic equivalence principle and a Lyapunov theory, proving accuracy of frequency recovery of the linearized microgrid distributed secondary control strategy based on the virtual synchronous machine. The method and system provides inertia support, significantly reduces communication and computing resources, and helps the microgrid to operate safely and stably.

A microgrid distributed secondary control method based on a virtual synchronous machine, comprising:

step 1:
designing a microgrid primary control strategy based on the virtual synchronous machine, and establishing a microgrid distributed secondary control model based on the virtual synchronous machine by combining a speed regulator equation of the virtual synchronous machine;
wherein
in the step 1, the microgrid distributed secondary control model based on the virtual synchronous machine is as follows:
θ
˙
ι
(
t
)
=
ω
i
(
t
)
;
ω
˙
ι
(
t
)
=
1
J
i
⁢
(
P
i
*
-
P
i
(
t
)
-
D
i
(
ω
i
(
t
)
-
ω
n
⁢
i
(
t
)
)
)
+
Ω
i
(
t
)
=
Ω
i
ω
(
i
)
;
wherein θi(t) is a phase of a virtual synchronous machine i;
ωi (t) and ωni (t) are an output frequency and a frequency setting value of the virtual synchronous machine i, respectively;
Ji=JMiωni (t) is an improved moment of inertia of the virtual synchronous machine i;
Di=kωi+DMi is an improved damping coefficient of the virtual synchronous machine i;
JMi and DMi are a moment of inertia and a damping coefficient of the virtual synchronous machine i, respectively;
kωi is an adjustment coefficient;
P
i
*
is a rated active power of the virtual synchronous machine i;
Pi(t) is a mechanical output active power of the virtual synchronous machine i;
and Ωi(t) and Ωiω(t) are an error tracking auxiliary control coefficient and an auxiliary frequency control coefficient of the virtual synchronous machine i, respectively;
ωni (t) is as follows:
ω
n
⁢
i
(
t
)
=
∫
(
ψ
i
(
t
)
+
Ω
i
(
t
)
-
1
k
ω
i
⁢
φ
i
P
(
t
)
)
⁢
dt
;
wherein
φ
i
P
(
i
)
is a derivative or quadratic compensation;
ψi(t) is as follows:
ψ
i
(
t
)
=
1
J
i
⁢
(
P
i
*
-
P
i
(
t
)
-
D
i
(
ω
i
(
t
)
-
ω
n
⁢
i
(
t
)
)
)
;
step 2:
considering nonlinear characteristics of the virtual synchronous machine, based on a deterministic equivalence principle, designing a linearized microgrid distributed secondary control strategy based on the virtual synchronous machine;
wherein
in the step 2, the linearized microgrid distributed secondary control strategy based on the virtual synchronous machine is as follows:
z
i
(
t
)
=
ω
ˆ
i
(
t
)
-
ω
i
(
t
)
;
ω
ˆ
.
i
(
t
)
=
Ω
i
ω
ˆ
(
t
)
;
Ω
i
(
t
)
=
γ
i
⁢
z
i
(
t
)
-
ψ
i
(
t
)
+
Ω
i
ω
ˆ
(
t
)
;
wherein zi (t) is an estimated error;
{circumflex over (ω)}i(t) is an estimated value of ωi (t);
ωi(t) is the output frequency of the virtual synchronous machine i;
Ω
i
ω
ˆ
(
t
)
is a control variable or reference value tracking;
Ωi(t) is the error tracking auxiliary control coefficient of the virtual synchronous machine i;
γi is a first control gain;
and ψi(t) is as follows:
ψ
i
(
t
)
=
1
J
i
⁢
(
P
i
*
-
P
i
(
t
)
-
D
i
(
ω
i
(
t
)
-
ω
n
⁢
i
(
t
)
)
)
;
wherein Ji=JMiωni (t) is the improved moment of inertia of the virtual synchronous machine i;
Di=kωi+DMi is the improved damping coefficient of the virtual synchronous machine i, JMi and DMi are the moment of inertia and the damping coefficient of the virtual synchronous machine i, respectively;
kωi is the adjustment coefficient;
Pi* is the rated active power of the virtual synchronous machine i;
Pi(t) is the mechanical output active power of the virtual synchronous machine i;
and ωni(t) is the frequency setting value of the virtual synchronous machine i;
Ω
i
ω
ˆ
(
t
)
is as follows:
Ω
i
ω
ˆ
(
t
)
=
σ
ω
⁢
λ
i
(
t
)
;
wherein σω is a second control gain;
and λi(t) is an auxiliary control variable;
λi(t) is as follows:
λ
i
(
t
)
=
-
∑
j
∈
N
i
a
ij
(
ω
i
(
t
)
-
ω
j
(
t
)
)
-
g
i
⁢
0
(
ω
i
(
t
)
-
ω
i
r
⁢
e
⁢
f
)
-
β
i
⁢
z
i
(
t
)
;
wherein Ni is a set of neighbors of the virtual synchronous machine i;
αij is a connection gain;
gi0=I means that the virtual synchronous machine i is connected to a reference value;
ωiref is a frequency reference value;
and βi is a consensus control gain;
ω
i
r
⁢
e
⁢
f
is as follows:
ω
i
r
⁢
e
⁢
f
=
lim
t
→
∞
ω
i
(
t
)
;
wherein i=1, 2, . . . , n;
and
step 3:
based on the deterministic equivalence principle and a Lyapunov theory, proving an accuracy of frequency recovery of the linearized microgrid distributed secondary control strategy based on the virtual synchronous machine.

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Microgrid distributed secondary control method and system based on virtual synchronous machine

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Microgrid distributed secondary control method and system based on virtual synchronous machine

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Abstract

Claims12