CN-121984359-A - Optimized control method and system for DC link current ripple in three-phase current source rectifier based on sector division

CN121984359ACN 121984359 ACN121984359 ACN 121984359ACN-121984359-A

Abstract

The invention belongs to the technical field of rectifiers and provides an optimized control method and system for DC link current ripple in a three-phase current source rectifier based on sector division, wherein the method comprises the following steps of firstly, identifying the operation area of the current three-phase current source rectifier based on a bivariate operation area judging mechanism of a modulation index and a sector angle; and finally, according to the selected modulation strategy, synthesizing the acting time of each reference vector, and finally generating a driving signal sequence of the three-phase current source rectifier. The invention can ensure the electric energy quality output by the three-phase current source rectifier.

Inventors

HE XIONG
HE ZHENGSONG
HU BIN
ZHAO WEI
ZENG JIANGBO

Assignees

湖北英特利电气有限公司

Dates

Publication Date: 20260505
Application Date: 20260130

Claims (9)

1. The optimized control method of the DC link current ripple in the three-phase current source rectifier based on sector division is characterized by comprising the following steps: identifying the operation area of the current three-phase current source rectifier based on a bivariate operation area judging mechanism of a modulation index and a sector angle; selecting corresponding modulation strategies based on the operation area of the current three-phase current source rectifier, so that each modulation strategy operates in the optimal interval; And according to the selected modulation strategy, synthesizing the action time of each reference vector, and finally generating a driving signal sequence of the three-phase current source rectifier.
2. The method for optimally controlling dc link current ripple in a sector-based three-phase current source rectifier of claim 1, wherein said modulation index is used Representing the modulation index From the amplitude of the fundamental wave of the input voltage With the output voltage reference amplitude Relationship determination, calculated in real time by the controller, the formula is as follows: The controller is based on Judging whether the current three-phase current source rectifier belongs to a low modulation area or a high modulation area, when When the current three-phase current source rectifier belongs to the low modulation region When the current source rectifier belongs to the high modulation area.
3. The method for optimally controlling dc link current ripple in a three-phase current source rectifier based on sector division according to claim 2, wherein the sector angle is used Representing the sector angle The method is characterized by comprising the following steps of: Nine switching states of six bridge arms of the three-phase current source rectifier are obtained, wherein the nine switching states comprise six non-zero vector switching states and three zero vector switching states; the controller uses three-phase input voltage As a benchmark, it is transformed into a two-phase stationary coordinate system: Resolving the sector angle of the reference vector in real time by the following formula : According to three-phase input voltage The input voltage is divided into 12 sectors, each sector corresponding to a different current trend interval.
4. The method for optimally controlling dc link current ripple in a sector-divided three-phase current source rectifier according to claim 3, wherein the sector angle After the judgment is completed, current trend interval identification is carried out; the current trend interval identification means when When it is, according to sector angle With a preset boundary angle If the magnitude relation of (3) is judged If the modulation strategy is located in the ripple rising trend section, the modulation strategy is suitable for zero vector division, and if the modulation strategy is And the non-zero vector division modulation strategy is suitable for the non-zero vector division modulation strategy or the improved non-zero vector division modulation strategy when the non-zero vector division modulation strategy is positioned in the ripple descending trend interval.
5. The method for optimally controlling the current ripple of the direct current link in the three-phase current source rectifier based on the sector division according to claim 2, wherein the selection of the corresponding modulation strategy based on the operation area of the current three-phase current source rectifier is that: If it is When the current three-phase current source rectifier belongs to a high modulation area, the controller automatically starts a current ripple suppression modulation strategy, and the strategy utilizes three vectors of a first current, a fifth current and a sixth current of corresponding switching tubes in six bridge arms of the three-phase current source rectifier to synthesize a reference vector for suppressing direct current link ripple under a high power working condition; If it is I.e. when the current three-phase current source rectifier belongs to the low modulation region, the sector angle is obtained And judging the current trend interval to which the current trend interval belongs: When (when) In the first current trend interval, i.e. When the current trend is in a regular ascending-descending-ascending-descending mode, a zero vector division modulation strategy is selected, wherein the action vector of the zero vector division modulation strategy is a first current/fifth current+zero vector, A boundary angle between the zero vector direction and the current reference vector direction; When (when) In the second type of current trend interval, i.e. When a non-zero vector division modulation strategy or a modified non-zero vector division modulation strategy is selected, the non-zero vector division modulation strategy is synthesized by three non-adjacent active vectors.
6. The method for optimally controlling dc link current ripple in a sector-based three-phase current source rectifier of claim 5, wherein said modified non-zero vector division modulation strategy is: When the corresponding switching tubes in six bridge arms of the three-phase current source rectifier are added with current vectors on the basis of vector synthesis of a non-zero vector division modulation strategy, a new virtual vector is constructed : Wherein, the For the added current vector, the action time is set to be the fifth current One fourth of (3); The improved non-zero vector division modulation strategy is used for enabling the situation that only two switching tubes are used for converting current to occur in the switching process of any current vector.
7. The method for optimally controlling dc link current ripple in a sector-based three-phase current source rectifier of claim 6, wherein said improved non-zero vector split modulation strategy redistributes vector on time as follows: Principal vector Maintaining the basic action time; Compensation vector The action time is as follows One fourth of (3); Zero vector action time is shortened; The first current/the third current is used as an auxiliary action vector; and after the improved non-zero vector segmentation modulation strategy redistributes vector action time, outputting an optimized vector action sequence.
8. The method for optimally controlling the current ripple of a dc link in a three-phase current source rectifier based on sector division according to any one of claims 1 to 7, wherein the step of synthesizing the time of application of each reference vector according to the selected modulation strategy to finally generate a driving signal sequence of the three-phase current source rectifier comprises the steps of: according to the selected strategy, the reference current vector is decomposed into a number of active vectors: Wherein, the In order to be able to take the time of the vector action, For the active vector in the selected policy, Can be zero vector or virtual vector Normalizing the action time: Wherein, the Is a switching period; Generating a switching sequence conforming to a space vector modulation rule by using vector action time, and automatically changing a sequence structure according to different modulation modes; According to the topological action relation corresponding to the vector, outputting a voltage driving signal sequence of six switching tubes in six bridge arms of the three-phase current source rectifier ; The voltage driving signal sequence of the six-way switching tube is used for directly controlling the power device of the three-phase current source rectifier.
9. The optimized control system for the direct current link current ripple in the three-phase current source rectifier based on sector division is applied to the optimized control method for the direct current link current ripple in the three-phase current source rectifier based on sector division as set forth in any one of claims 1 to 8, and is characterized by comprising the following steps: the operation area judging module is used for identifying the operation area of the current three-phase current source rectifier based on a bivariate operation area judging mechanism of the modulation index and the sector angle; The strategy switching module is used for selecting a corresponding modulation strategy based on the operation area of the current three-phase current source rectifier, so that each modulation strategy operates in the optimal interval; And the modulation vector synthesis module is used for synthesizing the action time of each reference vector according to the selected modulation strategy and finally generating a driving signal sequence of the three-phase current source rectifier.

Description

Optimized control method and system for DC link current ripple in three-phase current source rectifier based on sector division Technical Field The invention relates to the technical field of rectifiers, in particular to an optimized control method and system for DC link current ripple in a three-phase current source rectifier based on sector division. Background The three-phase current source rectifier (Current Source Rectifier, CSR) has the advantages of unit power factor operation, stable and controllable DC bus voltage, good sine waveform of input current, strong short-circuit protection capability and the like due to the inherent structural characteristics, and is widely applied to the scenes of data center power supply systems, multi-electric aircraft power supply systems, high-reliability industrial power supplies, renewable energy grid-connected devices and the like. In these applications, the power quality and system reliability requirements are extremely high, so the direct link current (DC-link current) quality of the CSR directly affects the performance and stability of the overall power supply system. However, CSR generally faces the problem of large direct current link current ripple (DC-link current ripple) during actual operation. Excessive inductor current ripple can lead to the following adverse effects: (1) The distortion of the input current is increased, and the electric energy quality is damaged; (2) The switching tubes and the inductors of the rectifier and the later-stage converter bear extra stress, so that the system loss is increased; (3) Can cause stronger electromagnetic interference (EMI), which is unfavorable for meeting the electromagnetic compatibility standard; (4) Protection actions may be triggered under some extreme conditions, degrading system reliability. Therefore, suppression of dc link current ripple is one of the key issues in high performance CSR modulation research. In the prior art, dc link current ripple suppression for CSR is mainly dependent on optimization of the modulation strategy. Typical methods include Zero vector separation modulation strategies (Zero-Vector Partition Modulation, ZPM) and Non-Zero vector separation modulation strategies (Non-Zero Vector Partition Modulation, NZPM). The strategy reasonably distributes the action time of different space vectors in one switching period so as to realize accurate synthesis of the reference current vector and further reduce current ripple. However, since the space vector action sequence of the strategy cannot keep the balance of the variation trend of the inductance current in certain electric angle intervals, the phenomenon that the current continuously rises or continuously drops can occur, so that the current ripple of the direct current link is obviously amplified in the specific areas. In order to solve the above-mentioned problems, a kind of "mixed current ripple suppression strategy" has been proposed, that is, different current vector synthesis schemes are switched under different modulation indexes, so as to improve the modulation performance of different working areas. However, such mixing strategies generally have the following limitations: (1) The strategy switching depends on the magnitude of the modulation index, wherein more research uses CRRM (current ripple suppression modulation) only for the modulation index Is a section of (2); (2) In the low modulation index interval ) In the meantime, since the available distribution of the voltage space vector is limited, the CRRM scheme cannot satisfy the volt-second balance condition, and thus cannot be executed; (3) Existing mixing strategies are described in The region still generally depends on the traditional ZPM or NZPM method, but the above strategy has a serious problem of unbalanced trend of inductance current in the region, so that current ripple cannot be effectively restrained, and the electric energy quality of the three-phase current source rectifier output in the application scene of a smart grid and the like is affected. Disclosure of Invention The invention aims to provide an optimized control method and system for DC link current ripple in a three-phase current source rectifier based on sector division, which can improve the electric energy quality of the three-phase current source rectifier output in application scenes such as a smart grid. The invention solves the technical problems and adopts the following technical scheme: on the one hand, the invention provides an optimized control method of DC link current ripple in a three-phase current source rectifier based on sector division, which comprises the following steps: identifying the operation area of the current three-phase current source rectifier based on a bivariate operation area judging mechanism of a modulation index and a sector angle; selecting corresponding modulation strategies based on the operation area of the current three-phase current source rectifier, so that eac