Three-phase four-switch APF switching control method based on Lyapunov

Abstract

The invention discloses a three-phase four-switch APF switching control method based on Lyapunov. The method comprises the steps that a three-phase four-switch APF topological structure is analyzed first; a state equation of a switch function and the three-phase four-switch APF topological structure under a three-phase static coordinate system are established; a state equation of the three-phase four-switch APF topological structure under instruction currents is written, difference of the two state equations is achieved, an error state equation is obtained; voltages output in the three-phase static coordinate system under different switch modalities are converted into a two-phase static coordinate system; a controller is designed based on Lyapunov, on the basis of conversion of coordinates, the relationship between error currents and changing rate included angle thereof is analyzed under the two-phase static coordinate system, a switching rule which accords with the stability theorem is obtained; third, a control rule is obtained through the method, and connection and disconnection of a three-phase four-switch APF are controlled. Compared with a three-phase four-switch SVPWM algorithm, complex modulation processes are omitted through the method.

Description

technical field [0001] The invention specifically discloses a three-phase four-switch APF switching control method based on Lyapunov. Background technique [0002] In practical applications, the power devices of the three-phase six-switch active power filter will have reliability problems if they run for a long time. When a short-circuit fault occurs in one of the IGBTs of the filter, not only the compensation effect of the filter cannot be guaranteed, but even serious consequences will be caused. Aiming at the above problems, the researchers proposed a three-phase six-switch filter fault-tolerant topology circuit to restore the original compensation effect of the filter as much as possible. The three-phase four-switch filter is a fault-tolerant topology circuit after the fault reconstruction of the three-phase six-switch filter, and the cost of the active filter is reduced due to the reduction of switching devices, so the study of the three-phase four-switch APF has import...

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Problems solved by technology

[0003] Compared with the three-phase six-switch APF, the three-phase four-switch APF actuator is reduced by one-third, and can only output four unequal voltage vectors without zero vector, which will inevitably increase the difficulty of control and affect the compensation performance of the filter.

[0005] Literature "Wang Wen, Luo An, Li Yan, et al. A new type of SVPWM algorithm for active power filters [J]. Chinese Journal of Electrical Engineering, 2012, 32(18): 52-58." also

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