# US 2026/0074516 A1 · VSG Frequency Control Method, Device and Storage Medium Based on Power Correction

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- Number: US 2026/0074516 A1
- Document ID: US20260074516A1
- Status: Published application
- Kind: A1
- Application number: 19/275,980
- Filed: 2025-07-22
- Published: 2026-03-12
- Earliest claimed: 2023-12-21
- Assignees: Datang Boiler Pressure Vessel Inspection Center Co., Ltd.; China Datang Corporation Science and Technology General Research Institute Co.Ltd East China Elect; Zhejiang Datang International Renewable Power Co., Ltd.; Guangdong Datang International Chaozhou Power Generation Co., Ltd.
- Applicants: Datang Boiler Pressure Vessel Inspection Center Co., Ltd.; China Datang Corporation Science and Technology General Research Institute Co.Ltd East China Elect; Zhejiang Datang International Renewable Power Co., Ltd.; Guangdong Datang International Chaozhou Power Generation Co., Ltd.
- Inventors: Xing Wang; Jiazhu WEI; Liang LOU; Chaonan ZHANG; Tianpeng YU; Ping WANG; Miao ZHAO; Yulei YANG
- Web page: https://patentgrep.com/patent/US20260074516A1

## CPC

- H02J 3/00142: {Oscillations concerning frequency}
- G05B 13/042: {in which a parameter or coefficient is automatically adjusted to optimise the performance}
- H02J 3/381: {Dispersed generators}
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)

## Abstract

VSG Frequency Control Method, Device and Storage Medium based on Power Correction, belonging to the field of power electronics technology, which addresses the problem of suppressing VSG output power oscillations. The technical solution of the present application corrects the output power Pe(s) and feeds the corrected value back to the control loop to suppress power oscillations. The transfer function of the power correction stage G(s) is flexible and can be configured with appropriate parameters according to the system's inherent phase margin. Additionally, principles for selecting the parameters of the correction coefficients τ1 and τ2 are also provided. The adjustment coefficients of the power correction stage, the values of τ1 and τ2 do not affect the effect of the steady-state gain during the transient process. The present application can not only suppress VSG output power oscillations, but also provide a larger inertial support, thereby improving the stability of the VSG system.

## Claims

### Claim 1

A Virtual Synchronous Generator (VSG) frequency control method based on power correction, comprising the following steps:
S1. obtaining an output power Pe(s) in the VSG control loop, multiplying the out power by a transfer function G(s) of a correction stage, and feeding it back to a frequency generation stage of an active power-frequency control loop, wherein Pe(s) refers to an output power at a VSG grid connection point, obtained through sampling and calculation;
S2. obtaining a frequency ω according to the active power-frequency control stage in the VSG control loop, and compensating the frequency generation stage from the step S1 into the control loop to obtain a compensated frequency ω*;
S3. designing the parameters of coefficients τ1 and τ2 in the transfer function G(s) of the power correction stage based on the transfer function G(s) of the power correction stage and in combination with the phase margin requirements of a system open-loop transfer function.

### Claim 2 (depends on 1)

The Virtual Synchronous Generator (VSG) frequency control method based on power correction according to claim 1, wherein a calculation formula of the output power Pe(s) is:
P
e
(
s
)
=
3
2
⁢
(
e
d
⁢
i
d
+
e
q
⁢
i
q
)
(
1
)
wherein ed, eq, id, and iq are the d-axis and q-axis components of the voltage and current at the sampling point PCC after abc/dq0 transformation, and s is the transformation parameter in the Laplace transform.

### Claim 3 (depends on 1)

The Virtual Synchronous Generator (VSG) frequency control method based on power correction according to claim 1, wherein the expression of the frequency ω is:
ω
=
(
P
ref
(
s
)
-
P
e
(
s
)
)
⁢
1
J
⁢
ω
0
⁢
s
+
D
p
⁢
ω
0
+
ω
0
(
2
)
wherein J is a virtual inertia coefficient, Dp is a damping coefficient, Pref(s) is a reference power, and ω0 is a grid rated angular frequency.

### Claim 4 (depends on 3)

The Virtual Synchronous Generator (VSG) frequency control method based on power correction according to claim 3, wherein the expression of the compensated frequency ω* is:
ω
*
=
(
P
ref
(
s
)
-
P
e
(
s
)
)
⁢
1
J
⁢
ω
0
⁢
s
+
D
p
⁢
ω
0
+
ω
0
-
P
e
(
s
)
⁢
G
⁡
(
s
)
(
3
)
wherein G(s) is a transfer function of the correction stage.

### Claim 5 (depends on 4)

The Virtual Synchronous Generator (VSG) frequency control method based on power correction according to claim 4, wherein the expression of transfer function of the correction stage is:
G
⁡
(
s
)
=
-
τ
2
⁢
s
(
1
+
τ
1
⁢
s
+
τ
2
⁢
s
)
⁢
G
2
(
s
)
(
4
)
wherein τ1 and τ2 are regulation coefficients of the power correction stage, and G2(s) is a transfer function from an angular frequency Δω in a Virtual Synchronous Generator (VSG) small-signal model to output power Pe(s).

### Claim 6 (depends on 5)

The Virtual Synchronous Generator (VSG) frequency control method based on power correction according to claim 5, wherein the expression of the transfer function G2(s) from the angular frequency Δω in the Virtual Synchronous Generator (VSG) small-signal model to output power Pe(s) is:
G
2
(
s
)
=
K
s
(
s
)
s
=
3
⁢
E
⁢
U
g
(
s
⁢
L
X
+
R
X
)
2
+
(
ω
0
⁢
L
X
)
2
s
(
5
)
wherein, LX is the sum of filter inductance Lf and transmission line inductance Lg, RX is the sum of the resistances in transmission line, E is a VSG output voltage amplitude, and Ug is a grid-side voltage.

### Claim 7 (depends on 6)

The Virtual Synchronous Generator (VSG) frequency control method based on power correction according to claim 6, wherein the expression of the system open-loop transfer function is:
G
open
(
s
)
=
1
(
J
⁢
ω
0
⁢
s
+
D
p
⁢
ω
0
)
⁢
G
2
(
s
)
⁢
1
+
(
τ
1
+
τ
2
)
⁢
s
1
+
τ
1
⁢
s
(
6
)
wherein the system's phase margin is expressed as:
P
⁢
M
=
180
⁢
°
+
∠
[
G
open
(
s
)
]
(
7
)
wherein using the system's phase margin as an indicator to design the parameters of the adjustment coefficients τ1 and τ2 of the power correction stage.

### Claim 8 (depends on 7)

The Virtual Synchronous Generator (VSG) frequency control method based on power correction according to claim 7, wherein the process for designing the parameters of the adjustment coefficients τ1 and τ2 of the power correction stage is as follows:
equivalently representing the power correction stage as a lead-lag compensator, with its characteristic expressed as:
{
φ
⁡
(
ω
m
)
=
arctan
⁢
τ
2
τ
1
2
⁢
τ
1
+
τ
2
τ
1
ω
m
=
1
τ
1
⁢
τ
1
+
τ
2
τ
2
(
8
)
wherein φ(ωm) is a maximum lead angle provided by the power correction stage, and ωm is an angular frequency corresponding to the maximum lead angle;
wherein the cutoff frequency and system's phase margin can be derived from formula (6), with the expression shown in formula (9):
{
❘
"\[LeftBracketingBar]"
❘
"\[LeftBracketingBar]"
G
2
(
s
)
❘
"\[RightBracketingBar]"
⁢
(
(
τ
1
+
τ
2
)
⁢
ω
c
)
2
+
1
(
J
⁢
ω
0
⁢
ω
c
)
2
+
(
D
p
⁢
ω
0
)
2
·
(
τ
1
⁢
ω
c
)
2
+
1
❘
"\[RightBracketingBar]"
=
1
γ
=
180
⁢
°
-
arctan
⁢
J
⁢
ω
c
D
p
+
∠
⁢
G
2
(
ω
c
)
+
φ
⁡
(
ω
c
)
(
9
)
wherein ωc is the cutoff frequency of the VSG system after adding active power correction, φ(ωc) is the corresponding phase angle at this cutoff frequency after adding power correction, the specific expression is:
φ
⁡
(
ω
c
)
=
arctan
⁢
τ
2
⁢
ω
c
1
+
τ
1
(
τ
1
+
τ
2
)
⁢
ω
c
2
(
10
)
setting ωc=ωm, and substituting formula (8) and (10) into formula (9) to obtain the binary formula s for τ1 and τ2 as shown in formulas (11) and (12):
τ
1
=
D
p
2
⁢
τ
1
+
τ
2
τ
1
+
(
D
p
⁢
ω
0
)
4
⁢
(
τ
1
+
τ
2
τ
1
)
2
+
4
⁢
❘
"\[LeftBracketingBar]"
G
2
(
s
)
❘
"\[RightBracketingBar]"
2
⁢
(
τ
1
+
τ
2
τ
1
)
3
⁢
(
J
⁢
ω
0
)
2
2
⁢
❘
"\[LeftBracketingBar]"
G
2
(
s
)
❘
"\[RightBracketingBar]"
2
⁢
(
τ
1
+
τ
2
τ
1
)
3
(
11
)
τ
1
=
J
⁢
ω
0
D
p
⁢
ω
0
⁢
2
⁢
(
τ
1
+
τ
2
τ
1
)
1
2
(
τ
1
+
τ
2
τ
1
)
3
2
+
2
⁢
cot
⁢
γ
-
(
τ
1
+
τ
2
τ
1
)
1
2
(
12
)
selecting the phase margin γ, combine formula s (11) and (12) to determine the specific values of parameters τ1 and τ2.

### Claim 9

(canceled)

### Claim 10

(canceled)