Secondary Frequency Control Method of Microgrid System Inverter Based on Virtual Synchronous Generator

A virtual synchronization and control method technology, applied in the direction of single-network parallel feeding arrangement, reducing/preventing power oscillation, etc., can solve the problems of not considering the dynamic response characteristics of system frequency, etc., to optimize dynamic response characteristics, improve steady-state error, Effect of Fast Frequency Recovery Rate

Active Publication Date: 2021-04-30
SHANGHAI UNIVERSITY OF ELECTRIC POWER
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  • Application Information

AI Technical Summary

Problems solved by technology

The integrator feedback is introduced into the VSG rotor motion equation, combined with the damping torque to provide frequency support for the microgrid, and realizes the error-free control of the frequency when the load is disturbed, but does not consider the dynamic response characteristics of the system frequency

Method used

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  • Secondary Frequency Control Method of Microgrid System Inverter Based on Virtual Synchronous Generator
  • Secondary Frequency Control Method of Microgrid System Inverter Based on Virtual Synchronous Generator
  • Secondary Frequency Control Method of Microgrid System Inverter Based on Virtual Synchronous Generator

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0087] Such as figure 1 As shown, a microgrid simulation model with two VSGs running in parallel is built on the Matlab / Simulink simulation platform. The capacity of the two VSGs is equal, and the maximum allowable output active and reactive power is 20kW and 15kVar. The main simulation parameters are shown in Table 1. Show:

[0088] Table 1 System Simulation Parameters

[0089]

[0090] At the initial moment, VSG1 and VSG2 run in parallel with no load. When the system runs stably for 1 second, the local load suddenly increases by 20kW. As shown in Figure 6(a), the moment of inertia J changes. As J increases, the frequency offset rate decreases. small, but the frequency offset increases, and the frequency oscillation intensifies; as shown in Figure 6(b), the damping coefficient D changes, and with the increase of the coefficient D, the system frequency offset decreases, and the frequency oscillation is obviously weakened , but the system frequency stabilization time becom...

Embodiment 2

[0092] The configuration of VSG is the same as that of Example 1. At the initial moment, VSG1 and VSG2 run in parallel with no load. A 20kW load is put in for 1 second, and the load is cut off in 2 seconds. As shown in Figure 7(a), the two VSGs use the same control parameters. When the system load is disturbed When , the secondary frequency control strategy can quickly restore the system frequency to the rated value and realize the no-difference control of the frequency; as shown in Figure 7(b), where k p0 is the initial setting value, and K is a normal constant. When the load is disturbed, the system frequency can have a lower frequency deviation rate and a faster frequency recovery rate through adaptive control of the frequency deviation value.

[0093] The simulation comparison of Droop control, VSG control and VSG secondary frequency control is shown in Fig. 8(a) and Fig. 8(b). The output frequency of the system drops rapidly, and it belongs to differential control, and th...

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Abstract

The invention relates to a method for controlling the secondary frequency of a micro-grid system inverter based on a virtual synchronous generator. According to the dynamic response characteristics of the virtual synchronous generator frequency, the proportional integral is used to adaptively control the frequency deviation, and the frequency deviation is slowed down when the load is disturbed. The frequency offset rate speeds up the frequency recovery after the frequency change rate crosses zero and reverses, so that the system frequency has a lower frequency offset rate and a faster frequency recovery rate at the same time, and realizes the static error-free tracking of the microgrid system frequency. Compared with the prior art, the present invention has the advantages of optimizing frequency dynamic response characteristics, reducing frequency steady-state error, realizing system frequency with lower frequency offset rate and faster frequency recovery rate, and the like.

Description

technical field [0001] The invention relates to a microgrid frequency control method, in particular to a microgrid system inverter secondary frequency control method based on a virtual synchronous generator. Background technique [0002] As the penetration rate of distributed renewable energy continues to increase, the microgrid system composed of distributed power supply DG, energy storage device, power electronic inverter interface and controllable load is widely used. The microgrid inverter has two working modes: grid-connected and off-grid. During grid-connected operation, the microgrid inverter is used as the power electronic inverter interface of the distributed power supply. The low damping and low inertia characteristics of the power electronic device make the large-scale connection of distributed power supply bring impact to the operation of the grid. When running off-grid, the intermittent and fluctuating output of new energy sources such as wind power and photovo...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/48H02J3/50H02J3/24
CPCH02J3/24H02J3/48H02J3/50
Inventor 韩云昊颜丽米阳马宇辰王鹏方基泽乔思宇
Owner SHANGHAI UNIVERSITY OF ELECTRIC POWER
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