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Control method and system for three-phase grid-connected inverter without phase-locked loop

A technology without phase-locked loop and control method, applied in reactive power compensation, single-grid parallel feeding arrangement, reactive power adjustment/elimination/compensation, etc., can solve problems such as increasing control complexity and avoid locking grid voltage Phase time, simplified control process, good effect of grid voltage waveform distortion

Inactive Publication Date: 2020-01-21
STATE GRID CORP OF CHINA +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Therefore, to accurately control the output reactive power q of the VSR requires certain calculations, which increases the complexity of the control

Method used

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  • Control method and system for three-phase grid-connected inverter without phase-locked loop
  • Control method and system for three-phase grid-connected inverter without phase-locked loop
  • Control method and system for three-phase grid-connected inverter without phase-locked loop

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Embodiment

[0039] The control method of the three-phase grid-connected inverter without a phase-locked loop disclosed by the present invention uses a virtual vector as a reference coordinate, and directly controls the VSR to output constant active power and reactive power with a DC side voltage command and a reactive power command. The control block diagram is attached figure 1 As shown, the specific steps are discussed as follows:

[0040] Step 1: Collect the DC side capacitor voltage signal v dc , and use the DC voltage command v dc * and DC side capacitor voltage signal v dc The feedback of a PI regulator forms the DC side capacitor voltage v dc No static difference control, because the capacitor voltage is related to the active power output by the DC side, so the output of the PI regulator is the active power reference value p * . Active power reference value p * is given by the following control method:

[0041]

[0042] Among them, v s is the DC voltage source voltage, ...

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Abstract

The invention discloses a control method and system for a three-phase grid-connected inverter without a phase-locked loop. The method comprises the steps: performing synchronous rotating coordinate transformation on current outputted by a VSR with a virtual vector as a reference coordinate system to generate DC currents id and iq; respectively constructing active and reactive current inner loops by using the DC currents id and iq; performing decoupling operation on the DC voltage instruction vdc* and the reactive power instruction p* to generate active and reactive current inner loop instructions id* and iq* to directly control the active and reactive current inner loops so as to control the VSR to output active and reactive power. According to the method, a phase-locked loop is not required to lock the voltage phase of the power grid, a certain control flow is simplified, the time for locking the voltage phase of the power grid by the phase-locked loop is avoided, and the method is not influenced by sudden change of the voltage phase of the power grid and power grid voltage waveform distortion.

Description

technical field [0001] The invention belongs to a control method for a three-phase grid-connected inverter, and relates to a control method and system for a three-phase grid-connected inverter without a phase-locked loop. Background technique [0002] With the large-scale access of new energy to the grid, how to control the integration of new energy into the grid has become an important issue. Traditional diode rectifiers or thyristor phase-controlled rectifiers have the problems of causing serious harmonic pollution to the power grid and low power factor on the grid side. The PWM rectifier overcomes these shortcomings very well. It not only has high conversion efficiency, stability and reliability, but also has the advantages of adjustable power factor, adjustable DC voltage and will not bring harmonic pollution to the grid. Therefore, the PWM rectifier is used in The application in the power grid is more and more extensive. [0003] There are many control methods for PWM...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38H02J3/18
CPCH02J3/18H02J3/38Y02E40/30
Inventor 周鹏张彬张建段鑫杨洋陈文献王交通孙荣沙鹏
Owner STATE GRID CORP OF CHINA
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