Three-phase unbalance compensation apparatus based on fuzzy PI control

Abstract

The invention discloses a three-phase unbalance compensation apparatus based on fuzzy PI control. The apparatus herein includes a positive sequence compensation network, a negative sequence compensation network and a control module. The positive sequence compensation network brings an inverter AC side voltage source u<c0(1)> and a system side voltage source us through an inverter equivalent resistor R and a series reactor L. The negative sequence compensation network brings an inverter AC side voltage source u<c0(2)> into connection with the inverter equivalent resistor R and the series reactor L. The positive sequence control and the negative sequence control are under overlapping control. The positive sequence control uses ([Theta]<1>-[phi]<1>) uses indirect current control. The negative sequence control uses ([Theta]<2>-[phi]<2>) phase and modulation ratio to control negative sequence current and phase. The PI control module uses fuzzy rules and a fuzzy inference module to perform control so as to realize reactive compensation and three-phase load balance of a power distribution network.

Description

technical field [0001] The invention belongs to the technical field of circuit control, in particular to a three-phase unbalance compensation device based on fuzzy PI control. Background technique [0002] With the large number of non-linear loads such as modern power electronic equipment connected to the grid, the three-phase load of the distribution network is unbalanced; the unbalanced three-phase load will cause such as grid voltage, current imbalance, voltage fluctuation and flicker, low power factor, Many adverse effects such as line loss; seriously shorten the service life of the equipment, which will cause the power equipment to fail to work normally; a three-phase unbalance intelligent compensation device is disclosed in the application number 201610634677.X, including a signal sampling unit , a central control unit, a positive-sequence negative-sequence compensation unit, and a zero-sequence compensation unit; it is characterized in that: the signal sampling unit i...

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Problems solved by technology

[0002] With the large number of non-linear loads such as modern power electronic equipment connected to the grid, the three-phase load of the distribution network is unbalanced; the unbalanced three-phase load will cause such as grid voltage, current imbalance, voltage fluctuation and flicker, low power factor, Many adverse effects such as line loss; seriously shorten the service life of the equipment, which will cause the power equipment to fail to work normally; a three-phase unbalance intelligent compensation device is disclosed in the application number 201610634677.X, including a signal sampling unit , a central control unit, a positive-sequence negative-sequence compensation unit, and a zero-sequence compensation unit; it is characterized in that: the signal sampling unit is connected to a voltage sampling unit and a current sampling unit connected in series on the power grid; the signal sampling unit will be from the The information sampled by the voltage sampling unit and the current sampling unit is sent to the central control unit for processing and analysis, and the central control unit controls the positive-sequence negative-sequence compensation unit and zero-sequence compensation unit connected to the grid unit; the positive-sequence and negative-sequence compensation unit includes an LCL filter and a positive and negative-sequence IGBT inverter bridge, and the zero-sequence compensation unit includes a zigzag transformer T and a zero-sequence IGBT inverter bridge, which can effectively improve three-phase unbalance The resulting power loss and equipment damage can effectively compensate the zero-sequence current and negative-sequence current in the power grid, and the positive-sequence current will be transferred between phases to balance the three-phase current. Although this invention can achieve rapid adjustment and stability, its structure is complicated , the operation is inconvenient, and it needs to consume electric energy to improve stability and reliability. Therefore, it is necessary to propose a positive and negative sequence superposition compensation control method using a fuzzy controller to realize reactive power compensation and three-phase load balance of the distribution network.

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