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Ship shore power supply system and three-phase unbalanced load control method thereof

A technology for shore power supply and ships, which is applied in flexible AC power transmission systems, multiphase network asymmetry reduction, multiphase network elimination/reduction asymmetry, etc. Voltage imbalance and other problems, to ensure stable operation, simple implementation, and small calculation amount

Pending Publication Date: 2019-07-05
XIAN XJ POWER ELECTRONICS TECH +3
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  • Application Information

AI Technical Summary

Problems solved by technology

[0002] The ship's shore power supply has a three-phase unbalanced load, and the three-phase unbalanced load will lead to the appearance of a three-phase unbalanced current, which in turn will cause an unbalanced three-phase output voltage
The unbalance of the three-phase voltage will increase the power loss of the line and affect the life of the output transformer, which is not conducive to the stable operation of the electrical equipment, and may easily cause the failure of the inverter or the electrical equipment, or even burn out
[0003] In order to solve the unbalanced problem of the output three-phase voltage when the ship shore power supply has a three-phase unbalanced load, the existing technology usually uses the symmetrical component method to realize the positive, negative and zero sequence of the output voltage of the three-phase inverter under the unbalanced load. Component compensation to maintain the balance of the three-phase output voltage, but this method has many problems such as large amount of calculation, poor timing, and difficult to control, especially when the three-phase load is seriously unbalanced, the compensation effect is not obvious, and the unbalance degree still larger

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  • Ship shore power supply system and three-phase unbalanced load control method thereof
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  • Ship shore power supply system and three-phase unbalanced load control method thereof

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Embodiment Construction

[0019] The present invention will be described in further detail below in conjunction with the accompanying drawings.

[0020] see Figure 1-2 The ship shore power supply system of the present invention includes a multi-winding phase-shifting transformer 1 in structure, and the voltage of the shore power grid is divided into 3N groups of winding voltages of different phases through the multi-winding phase-shifting transformer 1, and N is the number of power module units. The multi-winding phase-shifting transformer 1 is connected to a three-phase rectifier 7, and the rectifier 7 adopts a diode rectifier to rectify the winding voltages of 3N groups of different phases, and then use them as DC input signals for each group of H-bridge units 8 composed of power switching devices. After cascading, the voltage is output through the inverter, the filter 3 and the isolation transformer 4 in order to realize power supply to the load. The filter 3 adopts a three-phase LC filter, and a ...

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Abstract

The invention relates to a ship shore power supply system and a three-phase unbalanced load control method thereof. Three-phase voltage balance of a shore power supply is realized by adjusting the amplitude value of the output three-phase voltage modulation degree in real time. Firstly, according to the difference between a three-phase voltage effective value and a rated phase voltage value, the phase voltage effective value corresponding to the minimum value is used as a reference value; then, the modulation degree after three-phase output voltage compensation is obtained according to the modulation degree before compensation multiplied by a proportionality coefficient; and the proportionality coefficient is obtainedby dividing the reference value by the corresponding phase voltage effective value. According to the ship shore power supply system and the three-phase unbalanced load control method thereof in the invention, steady operation of a shore power supply device and ship electrical equipment is ensured; and furthermore, the system has the advantages of being simple to realize, low in computation burden, high in timeliness, low in cost and high in reliability.

Description

technical field [0001] The invention belongs to the field of shore power supply, and relates to a ship shore power supply system and a three-phase unbalanced load control method thereof. Background technique [0002] Ship shore power supply has three-phase unbalanced load, which will lead to the appearance of three-phase unbalanced current, which will cause the unbalance of three-phase output voltage. The unbalance of the three-phase voltage will increase the power loss of the line, affect the life of the output transformer, is not conducive to the stable operation of the electrical equipment, and may easily cause the failure of the inverter or the electrical equipment, or even burn out. [0003] In order to solve the unbalanced problem of the output three-phase voltage when the ship shore power supply has a three-phase unbalanced load, the existing technology usually uses the symmetrical component method to realize the positive, negative and zero sequence of the output volt...

Claims

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Application Information

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IPC IPC(8): H02J3/26
CPCH02J3/26Y02E40/10Y02E40/50
Inventor 宋晓梅牛化鹏来璐冯宇鹏陈旭东高洪
Owner XIAN XJ POWER ELECTRONICS TECH
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