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Low-voltage ride-through device comprising bidirectional three-port DC/DC converter, and control method

A low-voltage ride-through and control method technology, applied in the direction of circuit devices, battery circuit devices, output power conversion devices, etc., can solve problems such as large voltage stress, low boost ratio, and complex control principles, and achieve small voltage stress, Effects of low device stress and simple circuit structure

Pending Publication Date: 2021-12-07
HARBIN UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The current converter has a low step-up ratio, high voltage stress, and complicated control principles due to the circuit structure.

Method used

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  • Low-voltage ride-through device comprising bidirectional three-port DC/DC converter, and control method
  • Low-voltage ride-through device comprising bidirectional three-port DC/DC converter, and control method
  • Low-voltage ride-through device comprising bidirectional three-port DC/DC converter, and control method

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Experimental program
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specific Embodiment approach 1

[0035] Such as figure 1 As shown, a low-voltage ride-through device including a bidirectional three-port DC / DC converter in this embodiment is placed between the network side of the pumped storage unit and the converter on the machine side to form an AC-DC-AC power converter, and the pumped-storage The energy generated by the unit voltage drop can be fed back to the super capacitor to absorb the excess active power injected into the DC bus by the machine-side converter that cannot be absorbed due to the limit of the maximum operating current of the grid-side converter, thereby preventing the bus voltage from increasing significantly. Keep the DC bus voltage of the system basically within the normal working voltage.

[0036] Such as figure 2 As shown, in this embodiment, a low-voltage ride-through device including a bidirectional three-port DC / DC converter has its front-stage input terminal connected to the power supply V, and its rear-stage output terminal connected to the l...

specific Embodiment approach 2

[0040] The capacitor C of this example 1 for the supercapacitor. This embodiment only needs one supercapacitor, and multiple supercapacitors will cause unnecessary waste. Under ideal working conditions, the capacitance C of the converter is 1 It only absorbs the energy of other energy storage elements and does not provide energy to other energy storage elements, the capacitance C 2 , capacitance C 3 , capacitance C 4 It not only absorbs the energy of other energy storage elements but also releases energy to other energy storage elements. In Boost mode, the excess energy caused by power fluctuations on the low-voltage side will first be fed back to the capacitor C 1 , reducing the workload of other components. Due to the rectifier diode D 7 setting, the excess energy caused by power fluctuations on the high voltage side in the Buck working mode will only be fed back to the capacitor C 1 middle. Capacitance C 1 The position closest to the three switch tubes is more con...

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PUM

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Abstract

The invention discloses a low-voltage ride-through device comprising a bidirectional three-port DC / DC converter, and a control method, belongs to the field of converter and motor control, and aims to solve the problem of grid connection under the condition that the voltage of a pumped storage unit is reduced. The circuit comprises a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a switch tube Q1, a switch tube Q2, a switch tube Q3, a rectifier diode D4, a rectifier diode D5, a rectifier diode D6, a rectifier diode D7 and an inductor L. A bidirectional three-port structure of an additional super capacitor is adopted, and energy can be fed back to the super capacitor in a bidirectional mode; the three-port structure can enable the switch unit corresponding to the lowest port voltage to keep straight-through, and only two unit high-frequency switches work at any time; and the super-capacitor energy storage system is high in charging and discharging speed, and more energy is released in unit time. Through the scheme, the grid connection frequency of the power generation system is reduced, the impact on the power grid is reduced, and the fault tolerance time of the pumped storage unit is prolonged.

Description

technical field [0001] The invention relates to the field of converter and motor control, in particular to a low-voltage ride-through device and a control method including a bidirectional three-port DC / DC converter. Background technique [0002] In the pumped storage unit, when a fault occurs, the voltage at the grid-connected point will drop. For protection purposes, the unit cannot be connected to the grid without interruption, resulting in the unit being disconnected from the grid. This will greatly increase the number of times the power generation system is connected to the grid and impact the grid. serious. Low voltage ride through is a requirement for the ability of grid-connected units to remain connected to the grid when the grid voltage drops. The current converter has low step-up ratio, high voltage stress, and complicated control principle due to circuit structure. Contents of the invention [0003] In order to overcome the above-mentioned defects in the prior...

Claims

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Application Information

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IPC IPC(8): H02M3/158H02M3/04H02M3/06H02M3/08H02J3/28H02J3/12H02J7/00H02J7/02
CPCH02M3/1582H02M3/04H02M3/06H02M3/08H02J3/28H02J3/12H02J7/02H02J7/0068H02J2207/50H02J2207/20
Inventor 张宇李凯孙玉田崔淑梅吴晓刚刘加洪胡江威
Owner HARBIN UNIV OF SCI & TECH