Multi-level inverter grid-connection method and apparatus based on fixed frequency finite set model prediction

A technology of multi-level inverter and finite set model, applied in the direction of output power conversion device, electrical components, single grid parallel feeding arrangement, etc. Switching frequency and other issues, to achieve the effect of easy digital realization, simple and reliable method

Inactive Publication Date: 2018-02-09
NANJING UNIV OF SCI & TECH
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Problems solved by technology

[0003] However, the finite set model predictive control itself is a nonlinear control strategy. When it is applied to the grid-connected control of multi-level inverters, it cannot form a constant switching frequency. It is very difficult and will bring problems such as electromagnetic compatibility

Method used

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  • Multi-level inverter grid-connection method and apparatus based on fixed frequency finite set model prediction
  • Multi-level inverter grid-connection method and apparatus based on fixed frequency finite set model prediction
  • Multi-level inverter grid-connection method and apparatus based on fixed frequency finite set model prediction

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Embodiment 1

[0094] The simulation result of embodiment is as shown in the figure: Figure 5 DC side midpoint voltage, Figure 6 Incoming active power, Figure 7 Incoming reactive power, Figure 8 Actual in-grid current and reference in-grid current, Figure 9 The voltage u of the middle point (O) of the AC output side (a) of the inverter relative to the DC side ao The spectrum distribution of the simulation parameters are shown in Table 1.

[0095] Table 1 Simulation parameters

[0096] Grid voltage e a (=e b =e c ) amplitude

311(V)

V dc

800(V)

C 1 (=C 2 )

500e-6(F)

lambda dc

1

T s

25e-6(s)

R

1(Ω)

L

4e-3(H)

P * 0

10(kW)

Q * 0

500(Var)

[0097] From the simulation results of Embodiment 1, it can be seen that the multi-level inverter grid-connected device and method of the fixed-frequency finite set model predictive control of the present invention can suppress the DC side...

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Abstract

The invention discloses a multi-level inverter grid-connection method and apparatus based on fixed frequency finite set model prediction. The multi-level inverter grid-connection method comprises thesteps of performing sampling on a three-phase network-in current and a three-phase network voltage, and performing Clark conversion on the sampled values; and next, by adopting a fixed frequency modelprediction algorithm, performing tracking control on the three-phase network-in current and direct current side neutral-point voltage suppression in a condition of maintaining constant switching frequency. The apparatus comprises a main power circuit, a control circuit and a detection circuit, wherein the main power circuit comprises an NPC three-phase three-level inverter and an L-shaped low-pass filter; and the detection circuit comprises a network-in current detection circuit, a network voltage detection circuit and a direct current side neutral-point voltage detection circuit. The finiteset model prediction grid-connection control of the multi-level inverter can be realized in a condition of maintaining constant switching frequency.

Description

technical field [0001] The invention relates to the technical field of DC-AC converters of electric energy conversion devices, in particular to a multi-level inverter grid-connected method and device based on fixed-frequency finite set model prediction. Background technique [0002] NPC (Neutral Point Clamped) three-phase three-level grid-connected inverter is a multi-level inverter widely used in medium and large-capacity distributed grid-connected power generation systems. Its control strategies mainly include: PI control, PR control, hysteresis control and finite set model predictive control. Among them, the finite set model predictive control has the advantages of strong robustness, rapidity, easy digital realization and consideration of inverter nonlinearity, etc., and is widely used in the grid-connected control of multi-level inverters. [0003] However, the finite set model predictive control itself is a nonlinear control strategy. When it is applied to the grid-con...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M7/487H02J3/38
CPCH02M7/487H02J3/38
Inventor 吕建国马丙辉王纪东阎亦然范林勇
Owner NANJING UNIV OF SCI & TECH
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