Micro-grid inverter frequency-difference-free control method based on virtual synchronous machine

A technology of virtual synchronous machine and control method, applied in the direction of reducing/preventing power oscillation, etc., can solve the problems of large frequency and deviation of the system, achieve the effect of eliminating frequency deviation, eliminating steady-state frequency deviation, and realizing seamless switching

Inactive Publication Date: 2018-06-05
赵志刚
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the active frequency droop control, the system will have a large frequency deviation when the power changes in a wide range

Method used

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  • Micro-grid inverter frequency-difference-free control method based on virtual synchronous machine
  • Micro-grid inverter frequency-difference-free control method based on virtual synchronous machine
  • Micro-grid inverter frequency-difference-free control method based on virtual synchronous machine

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Experimental program
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Embodiment Construction

[0015] specific implementation plan

[0016] Such as figure 1 As shown, the PCC (point of couple connection) voltage and the main grid voltage; the upper layer controls the given active and reactive power reference, obtains the output voltage reference value through the power outer loop and uses it as the input of the voltage and current inner loop, and passes through the inner voltage and current loop The control voltage of the inverter is obtained, and the control voltage is modulated by SVPWM to obtain a switch signal to control the switch of the switch tube.

[0017] Such as figure 2 As shown, when the frequency increment is not 0, due to the accumulative characteristics of the integrator, the output of the negative feedback branch increases, resulting in a decrease in the input of the controller and a decrease in the output frequency of the inverter; in the final steady state, the inverter The output frequency is equal to the given frequency. Therefore, the proposed c...

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Abstract

The invention discloses a micro-grid inverter frequency-difference-free control method based on a virtual synchronous machine. The micro-grid inverter frequency-difference-free control method comprises three parts including frequency-difference-free active-reactive power control, reactive power-voltage control and inner loop voltage-current control. In a rotor motion equation, a traditional damping link is replaced with frequency proportional integral feedback, thereby eliminating frequency offset in an isolated-grid mode and enabling the realization of multi-mode control of a micro-grid inverter. Through frequency integral feedback, the steady-state frequency deviation is eliminated; and controller modes do not need to be switched under different operating conditions, thereby being conductive to realizing the multi-mode control and seamless switching of the micro-grid inverter.

Description

technical field [0001] The invention relates to a control method for a micro-grid inverter, in particular to a control method for a micro-grid inverter without frequency difference based on a virtual synchronous machine. Background technique [0002] Microgrid is an important realization form of future energy system and has important social and economic significance. Distributed energy sources such as wind power and photovoltaics have great advantages in future microgrid systems due to their renewable and clean characteristics. As the penetration rate of distributed renewable energy continues to increase, as a link between distributed energy and distribution grids, the functions of inverters have been deeply explored and their beneficial effects have been fully affirmed, but at the same time they are also facing new requirements and challenges. challenge. [0003] The microgrid inverter has two working modes: grid-connected and isolated grid. During grid-connected operati...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/24
CPCH02J3/24
Inventor 赵志刚
Owner 赵志刚
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