Three-phase four-bridge-arm active power filter gird-connected interface and parameter design method

Abstract

The invention discloses a three-phase four-bridge-arm active power filter grid-connected interface and a parameter design method. The three-phase four-bridge-arm active power filter grid-connected interface is characterized in that the output sides of four bridge arms ABCN of a power unit are all connected with an LCL type grid-connected interface. The parameter design method comprises the first step of establishing comprehensive performance evaluation indexes, the second step of establishing constraint conditions, the third step of solving gird-connected interface parameters and the fourth step of verifying a ripple suppression effect. Firstly, evaluation indexes are established for all parameters affecting harmonic compensation and switching order ripple suppression effects; secondly, the constraint conditions are established based on the evaluation indexes, and then initial grid-connected interface parameters are obtained; finally, the reasonability of the parameters is verified through simulation and experiment. The parameter design process is performed under the condition of inter-phase decoupling, and the freedom degree of the parameter design is higher. According to the grid-connected interface and the parameter design method, reasonable grid-connected interface parameters can be quickly obtained, and therefore the method has excellent feasibility and high practical value.

Description

technical field [0001] The invention relates to the field of power systems, in particular to a grid-connected interface and a parameter design method of a three-phase four-arm type active power filter in power electronics technology. Background technique [0002] With the continuous increase of non-linear loads, power quality issues are receiving increasing attention. Active power filter (Active Power filter, APF) has gradually become the first choice for harmonic pollution control due to its advantages of high controllability and fast response. According to the classification of the structure integrated into the power grid, active power filters can be divided into three-phase three-wire (3P3W) and three-phase four-wire (3P4W). In practical applications, most low-voltage distribution networks are three-phase four-wire, and contain a large number of unbalanced loads and single-phase loads, so three-phase four-wire active power filters are widely used. [0003] According to ...

AI Technical Summary

Problems solved by technology

When the three-phase load imbalance is serious or there are many single-phase loads in the power grid, when the three-phase four-wire active power filter is used to control harmonic pollution, the output current of the N-phase neutral line of the device is relatively large, and the traditional L-type grid connection is adopted. The ripple suppression effect of the interface is not ideal, so it is considered to use the LCL type grid-connected interface on the output side of the N-phase bridge arm

At present, there are few domestic and foreign literatures proposing to use LCL type grid-connected interface on the output side of the ABCN four-bridge arm of the three-phase four-wire active power filter.

[0004] The output side of the ABCN four-bridge arm of the three-phase four-wire active power filter adopts the LCL type grid-connected interface. The following two issues need to be considered, that is, the suppression requirement of the neutral line ripple current is high and there is phase-to-phase coupling in the ABCN, thereby increasing Difficulty in designing grid-connected interface parameters

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