Voltage balance control method for microgrid inverter under unbalanced load condition
A control method and load balancing technology, which is applied to AC network circuits, electrical components, circuit devices, etc., and can solve problems such as unbalanced three-phase output voltages of microgrid inverters
Active Publication Date: 2018-09-04
HEFEI UNIV OF TECH
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[0011] The present invention proposes a voltage balance control method for microgrid inverters under unbalanced load conditions, which is used to solve the three-phase output of microgrid inverters caused by the ubiquity of three-phase unbalanced loads in low-voltage microgrids voltage imbalance problem
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[0066] The topological structure of the main circuit of the microgrid inverter involved in the present invention is as follows: figure 1 Shown, where: the DC power supply voltage is u dc ; The DC side power supply is connected to the three-phase full-bridge circuit, and the three-phase full-bridge circuit consists of six switch tubes 1 , s 2 , s 3 , s 4 , s 5 , s 6 Composed of series and parallel; u a , u b , u c is the midpoint voltage of the three bridge arms of the inverter; the midpoint of the three bridge arms is connected to an LC low-pass filter, L is the filter inductor, R is the internal resistance of the filter inductor, and C is the filter capacitor; i La i Lb i Lc is the three-phase inductor current of the inverter, u Ca , u Cb , u Cc is the three-phase output voltage of the inverter, i Oa i Ob i Oc It is the three-phase output current of the inverter.
[0067] The control system of the microgrid inverter under unbalanced load conditions is as foll...
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The invention relates to a voltage balance control method for a microgrid inverter under an unbalanced load condition. In a low-voltage microgrid, three-phase output voltages of the microgrid inverterare unbalanced due to the prevalence of unbalanced loads, and a certain control method needs to be adopted to control the output voltages of the microgrid inverter so as to ensure power supply quality. The invention provides the voltage balance control method which does not need to carry out positive and negative sequence separation on the output voltages of the inverter, and comprises the stepsof: regarding output voltage dq axis components of the inverter as input of a high-pass filter, thus 100 Hz pulsating quantities output by the high-pass filter are negative sequence voltage feedback values; setting a negative sequence voltage reference value to be zero volt; performing difference operation on the negative sequence voltage reference value and the negative sequence voltage feedbackvalues; passing error signals through a resonance controller; and superimposing output of the resonance controller on output of an inductive current inner ring, and realizing balance control of the output voltages of the inverter after modulation.
Description
technical field [0001] The invention relates to a voltage balance control method for a microgrid inverter under unbalanced load conditions, and belongs to the technical field of distributed power generation control for new energy power generation. Background technique [0002] With the development of society, the distributed power generation method of new energy power generation has attracted worldwide attention. Many countries have begun to increase support for new energy power generation, combining multiple distributed power sources in a certain area into a microgrid Grid-connected power generation in the form of micro-grid has two working modes: grid-connected operation and island operation. [0003] When operating in an isolated microgrid, it is required to provide users with three-phase AC power that meets the power quality requirements of the power system. Voltage unbalance is an important technical indicator to measure power quality. In a low-voltage microgrid, usual...
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IPC IPC(8): H02J3/26H02J3/38
CPCH02J3/26H02J3/38H02J3/381H02J2203/20Y02E40/50
Inventor 谢震陈世燚张兴
Owner HEFEI UNIV OF TECH