A three-phase four-wire converter power oscillation suppression and overcurrent suppression method
A three-phase four-wire system, power oscillation technology, applied in the direction of reducing/preventing power oscillation, AC network to reduce harmonics/ripple, harmonic reducing device, etc., can solve the complex control strategy of three-phase four-wire system, etc. problem, to achieve a good suppression effect, reduce the peak value of three-phase current, and easy to achieve the effect
Active Publication Date: 2022-07-29
TIANJIN UNIV
View PDF3 Cites 0 Cited by
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
However, the increase of control dimensions and degrees of freedom will make the control strategy of the three-phase four-wire system more complex, especially in the case of asymmetric grid faults, and there is little research on this aspect
Method used
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View moreImage
Smart Image Click on the blue labels to locate them in the text.
Smart ImageViewing Examples
Examples
Experimental program
Comparison scheme
Effect test
Embodiment Construction
[0026] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.
[0027] The control method of the present invention is based on the topology of the three-phase four-bridge grid-connected inverter, such as figure 1 shown. When an asymmetric fault occurs in the power grid, the three-phase four-wire system is usually accompanied by voltage amplitude drop and phase angle offset, so the instantaneous value of the three-phase AC voltage at this time has the following expression:
[0028]
[0029] where k a , k b , k c Indicates the drop depth of the three-phase voltage, when there is no drop k j The value is 1, the deeper the drop, k j closer to 0. On the contrary, if the voltage rises, then k j The value will be greater than 1. E represe...
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More PUM
Login to View More Abstract
The invention discloses a method for suppressing power oscillation and overcurrent of a three-phase four-wire system converter. The method is as follows: first, according to the grid fault voltage, given power, and current neutral current information, a three-phase reference current vector that satisfies the active power oscillation suppression condition under the current operating condition is calculated. Second, according to the amplitude and phase angle information of the three-phase reference current at the current moment, a neutral current reference vector that reduces the peak value of the three-phase current to the greatest extent is synthesized. Third, the current tracking controller is used to realize the tracking control of the three-phase current and the neutral current respectively. Fourth, the voltage signal obtained from the neutral current tracking control is injected into the three-phase SVPWM signal in the form of zero-sequence voltage to realize the closed-loop control of the overall system. On the premise of suppressing the active power oscillation on the grid side, this method reduces the peak value of the three-phase current to the greatest extent by adjusting the amplitude and phase angle of the neutral current, and at the same time ensures that the amplitude of the neutral current does not exceed the limit, and the control effect is close to the ideal that the system can achieve. best effect.
Description
technical field [0001] The invention relates to the field of grid-connected control of a three-phase four-wire system, in particular to a method for suppressing power oscillation and overcurrent of a three-phase four-wire system converter applied to asymmetric faults in the power grid. Background technique [0002] As a commonly used connection device between distributed power and power grid, grid-connected inverter can not only isolate distributed power and power grid, play the role of protecting distributed power, but also limit the influence of grid transient fault to the greatest extent. grid side. Most of the grid-connected inverters in the traditional sense use the three-phase three-wire grid-connected mode. However, because the three-phase four-wire grid-connected inverter has stronger flexibility and adaptability in low-voltage systems, the three-phase four-wire grid The grid-connected model has begun to attract more and more attention from the public. However, the...
Claims
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More Application Information
Patent Timeline
Login to View More Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/24H02J3/01
CPCH02J3/24H02J3/01Y02E40/40
Inventor 李晓涵何晋伟
Owner TIANJIN UNIV