CN108306316B - Positive and negative sequence coordination control system and method for chain type STATCOM in power grid voltage unbalance - Google Patents
Positive and negative sequence coordination control system and method for chain type STATCOM in power grid voltage unbalance Download PDFInfo
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- H—ELECTRICITY
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Abstract
The invention discloses a positive and negative sequence coordination control system and method for a chain type STATCOM when the voltage of a power grid is unbalanced, wherein the positive and negative sequence coordination control system comprises the following steps: the device comprises a power grid synchronous phase quick open-loop detection module, a global direct-current voltage control module, a positive sequence reactive compensation current calculation module, a positive sequence reactive instruction current calculation module, a positive sequence current decoupling control module, a negative sequence separation and negative sequence voltage calculation module, a power module average direct-current voltage control and voltage instruction synthesis module and a phase-shifting carrier modulation module. The invention utilizes an advanced power grid phase open-loop synchronous control method to deal with the random disturbance of the power grid voltage phase, separates the output voltage of the chain-type STATCOM device and the phase sequence of the power grid voltage in real time, discloses the relation between a phase shift angle and a modulation ratio required to be met by positive and negative sequence component coordination control, and provides a positive and negative sequence component coordination control method of the chain-type STATCOM device under the condition of power grid voltage unbalance.
Description
Technical Field
The invention belongs to the field of power quality management, and particularly relates to a positive and negative sequence coordination control method of a chain type STATCOM when the voltage of a power grid is unbalanced.
Background
The control of the chained statcom requires that the device be able to respond quickly to the reactive demand of the load, while still ensuring safe and stable operation of the device itself. Especially when applied to public power grids, the device must be able to withstand the impact of system faults, continue stable operation during system recovery, and provide timely and effective dynamic reactive support. If the STATCOM device only carries out positive sequence voltage control, the output current of the device exceeds the maximum turn-off current of the device due to the negative sequence voltage of the power grid of about 10%, when the system voltage drops rapidly due to serious asymmetric faults of the power grid, the STATCOM device is also subjected to overcurrent if the system voltage does not have corresponding control, and the working conditions threaten the safe operation of the device.
The control strategy of the chain-type STATCOM device mainly comprises the following steps: the current decoupling control, the active and reactive decoupling control, the nonlinear control and the like are mostly based on the condition that the system is three-phase symmetric. However, various disturbances such as lightning stroke, operation overvoltage, asymmetric short circuit fault, asymmetric sudden change of load and the like cause the power grid voltage to be asymmetric, and further affect the normal operation of the STATCOM. If the control is not carried out effectively aiming at the asymmetric working condition, the device can generate unbalanced current, the system loss is increased, the running performance is reduced, the device can be subjected to fault protection and quit running in serious conditions, and even the device can be directly damaged. The adverse effect of the power grid voltage unbalance on the chain-type STATCOM is deeply analyzed by a switch function method. However, during unbalanced operation of the grid, it is precisely at the critical moment that the device exerts reactive support. In this case, the continuous safety stability of the device itself should be considered first, and only then should the device be made to function, providing a stable and reliable reactive support for the system. When the voltage of the power grid is unbalanced, the existing method is generally to quit the operation to protect the device before the power grid returns to normal, and wait for the device to be put into operation again. However, the grid-connected closing process of the large-capacity STATCOM device is complex, and frequent switching in a short-time fault process is not beneficial to safe operation of the large-capacity STATCOM device, so that the STATCOM device is expected to still work in a grid-connected mode when the voltage of a power grid is unbalanced. On the basis, the feedback linearization sliding mode control method is used for realizing complete positive and negative sequence decoupling, but the method is complex in calculation and difficult in parameter setting, and cannot be applied to industrial devices. The zero-sequence voltage calculation method of the star-shaped chain type STATCOM based on the equivalent susceptance transformation method completes unbalanced current tracking control under a two-phase static coordinate system, but does not consider the current commonly used Y-shaped connection mode.
Disclosure of Invention
When the voltage of the power grid is unbalanced, the control strategy designed aiming at the balanced working condition of the power grid enables the STATCOM to only output positive sequence voltage, and the negative sequence component in the voltage of the power grid can cause the device to be over-current and quit the operation.
The technical solution of the present invention is explained as follows.
A positive and negative sequence component coordination control system of a chained STATCOM when the voltage of a power grid is unbalanced comprises a power grid synchronous phase quick open-loop detection module, a global direct-current voltage control module, a positive sequence reactive compensation current calculation module, a positive sequence reactive instruction current calculation module, a positive sequence current decoupling control module, a negative sequence separation module, a negative sequence voltage calculation module, a power module average direct-current voltage control module and a voltage instruction synthesis and phase-shifting carrier modulation module;
the power grid synchronous phase quick open-loop detection module is used for obtaining the real-time phase theta of the power grid voltage according to the power grid voltage detected by the Hall voltage sensor;
the positive sequence reactive compensation current calculation module is used for detecting the three-phase current i output by the STATCOM according to the Hall current sensorca、icb、iccObtaining the positive sequence compensation current i output by the STATCOM under the dq coordinate system+ cd、i+ cq；
The positive sequence reactive instruction current calculation module is used for calculating the three-phase load current i detected by the Hall current sensorla、ilb、ilcAnd the signal output by the q axis is used as a positive sequence reactive compensation current command value i of the chain type STATCOM device+ qref；
The global direct current capacitor voltage control module is used for detecting direct current side capacitor voltage values of all power units of the STATCOM according to 3N Hall voltage sensors, N is the number of power units of each phase, and a direct current capacitor voltage control algorithm is used for obtaining a d-axis positive sequence compensation current instruction value i of the chained STATCOM device+ dref；
The positive sequence current decoupling control module is used for obtaining a positive sequence output voltage instruction value u of the STATCOM device under a dq coordinate system by using a positive sequence current decoupling control algorithm according to output current signals of the positive sequence reactive compensation current calculation module, the positive sequence reactive instruction current calculation module and the global direct current capacitor voltage control module+ cd、u+ cq；
The negative sequence separation module is used for obtaining the negative sequence voltage u of the power grid under the dq coordinate system according to the detected power grid voltage and the phase theta- sd、u- sq；
The negative sequence voltage calculation module is used for generating a negative sequence component signal under a coordination control strategy according to output voltage signals of the negative sequence separation module and the positive sequence current decoupling control module;
the voltage instruction synthesis and phase-shift carrier modulation module is used for generating a PWM control signal of the inverter according to output signals of the positive sequence current decoupling control module, the negative sequence voltage calculation module and the module average voltage direct current control module, and performing positive and negative sequence coordination control on the chain-type STATCOM when the voltage of the power grid is unbalanced.
A positive and negative sequence coordination control method of a chain-type STATCOM when the voltage of a power grid is unbalanced comprises the following steps:
(1) detecting the voltage of a power grid by using a Hall voltage sensor, and detecting the real-time phase theta of the voltage of the power grid through a power grid synchronous phase quick open-loop detection module;
(2) three-phase current i output by STATCOM (static synchronous compensator) detected by Hall current sensorca、icb、iccAnd inputting the positive sequence compensation current i to a positive sequence reactive compensation current calculation module to obtain a positive sequence compensation current i output by the STATCOM under the dq coordinate system+ cd、i+ cq；
(3) Three-phase load current i detected by Hall current sensorla、ilb、ilcAnd the output signal of the q axis is used as a q axis positive sequence reactive compensation current instruction value i of the chain type STATCOM device+ qref；
(4) Detecting the direct-current side capacitor voltage value of each power unit of the STATCOM by using 3N Hall voltage sensors, inputting the direct-current side capacitor voltage value into a global direct-current capacitor voltage control module, wherein N is the number of power units of each phase of the device, and calculating by using a direct-current capacitor voltage control algorithm to obtain a d-axis positive sequence active compensation current instruction value i of the chain type STATCOM+ dref；
(5) Taking the output current signals of the steps (1) to (4) as input signals of a positive sequence current decoupling control module, and obtaining a positive sequence output voltage instruction value u of the STATCOM device under a dq coordinate system by using a positive sequence current decoupling control algorithm+ cd、u+ cq；
(6) The detected power grid voltage and the phase theta thereof are subjected to a negative sequence separation module to obtain the negative sequence voltage u of the power grid under the dq coordinate system- sd、u- sq；
(7) Taking the output signals of the steps (5) and (6) as input signals of a negative sequence voltage calculation module to obtain a negative sequence component under a coordination control strategy;
(8) and (5) taking the output of the direct current control module with the average voltage of the modules in the steps (5) and (7) as an input signal of the voltage instruction synthesis and phase-shift carrier modulation module, generating a PWM (pulse width modulation) control signal of the inverter, and performing positive and negative sequence coordination control on the chain-type STATCOM when the voltage of the power grid is unbalanced.
In the step (2), the expression of the positive sequence reactive compensation current calculation module is as follows:
in the step (3), the positive sequence reactive instruction current calculation formula is as follows:
in the step (4), the detected DC capacitor voltages of the 3N H-bridge modules are subjected to summation operation udc_sumThen, the voltage is added to a DC capacitor voltage command value of 3N timesdc_refAnd performing difference, and finally calculating the deviation voltage value through a PI regulator to obtain a d-axis positive sequence compensation current instruction value i under a dq coordinate system+ dref(ii) a Wherein the content of the first and second substances,
udc_ai、udc_bi、udc_cithe voltage of the direct current capacitor of each phase ith module in the actually sampled A, B, C three phases is respectively, and N is the number of each phase H-bridge module.
In the step (5), the positive sequence current decoupling control algorithm specifically calculates the following formula:
wherein, U+ cPositive sequence voltage, delta, output by inverter+The positive sequence voltage output for the inverter leads the phase shift angle of the positive sequence voltage of the grid.
In the step (6), the specific calculation formula of the negative sequence separation module is as follows:
wherein, U- sβ phase difference between negative and positive sequence components for grid negative sequence voltage.
The calculation formula of the negative sequence voltage calculation module is as follows:
wherein, U+ cFor positive sequence voltage, U, output by the inverter— sFor the negative sequence voltage of the grid, β is the phase difference between the negative and positive sequence components, δ+The positive sequence voltage output for the inverter leads the phase shift angle of the positive sequence voltage of the grid.
The positive and negative sequence coordination control relationship of the chain-type STATCOM when the voltage of the power grid is unbalanced is as follows:
δ+＝δ-
wherein m is+、m-The modulation ratios of positive sequence voltage and negative sequence voltage, U, respectively, output by the inverter+ s、U— sPositive and negative sequence voltages, delta, of the grid, respectively+The positive sequence voltage output by the inverter leads the phase shift angle, delta, of the positive sequence voltage of the grid-The negative sequence voltage output for the inverter leads the phase shift angle of the negative sequence voltage of the grid.
Through the technical scheme, the invention has the beneficial effects that:
the control system disclosed by the invention solves the problem of control of the chain-type STATCOM device when the power grid voltage is unbalanced, responds to the disturbance of the power grid voltage phase by utilizing an advanced power grid phase open-loop synchronous control method, realizes the phase sequence separation of the output voltage of the device and the power grid voltage, realizes the positive and negative sequence separation and coordination control of the output voltage of the chain-type STATCOM, decomposes the device into a positive sequence control part and a negative sequence control part, analyzes from the angle of power balance, obtains the relation between a phase shift angle and a modulation ratio required to be met by the positive and negative sequence coordination control, and provides a complete positive and negative sequence coordination control method of the chain-type STATCOM when the power grid voltage is unbalanced.
The control method of the invention firstly utilizes an advanced power grid voltage phase open-loop synchronous control method to deal with the disturbance of the power grid voltage phase, realizes the phase sequence separation of the output voltage of the device and the power grid voltage, realizes the positive and negative sequence separation and coordination control of the output voltage of the chained STATCOM, and generates the PWM control signal of the inverter by decomposing the device into a positive sequence control part and a negative sequence control part and taking the output signals of a positive sequence current decoupling control module, a negative sequence voltage calculation module and a module average voltage DC control module as the input signals of a voltage instruction synthesis and phase-shifting carrier modulation module, thereby realizing the positive and negative sequence component coordination control of the chained STATCOM when the power grid voltage is unbalanced. The method has good capability of coping with the unbalance of the system, and the device can stably run under the working conditions of asymmetrical system voltage and phase disturbance and simultaneously meet the requirement of reactive power compensation.
Drawings
FIG. 1 is a main circuit structure diagram of a Y-shaped chain type H-bridge STATCOM;
FIG. 2 is a positive and negative sequence coordination control block diagram of the chain-type STATCOM in the invention when the voltage of the power grid is unbalanced;
FIG. 3 is a block diagram of a global DC capacitor voltage control algorithm;
FIG. 4 is a block diagram of a positive sequence current decoupling control algorithm;
FIG. 5 is a graph of a grid voltage simulation waveform (grid voltage with 30% negative sequence component);
FIG. 6 is a STATCOM output current graph without coordinated control;
FIG. 7 is a STATCOM output current graph under coordinated control;
FIG. 8 is a graph of the degree of imbalance of the STATCOM output current;
fig. 9 is a graph of the reactive component of the system current in dq coordinate system.
Detailed Description
The positive and negative sequence coordination control system of the chain-type STATCOM adopted by the invention when the voltage of the power grid is unbalanced is shown as the attached figure 2, and comprises the following components: the device comprises a power grid synchronous phase quick open-loop detection module, a global direct-current voltage control module, a positive sequence reactive compensation current calculation module, a positive sequence reactive instruction current calculation module, a positive sequence current decoupling control module, a negative sequence separation and negative sequence voltage calculation module, a power module average direct-current voltage control and voltage instruction synthesis module and a phase-shifting carrier modulation module. The method is characterized in that the disturbance of the voltage phase of the power grid is coped with by utilizing an advanced power grid phase open-loop synchronous control method, the phase sequence separation of the output voltage of the device and the voltage of the power grid is realized, the positive and negative sequence separation and coordination control of the output voltage of the chain-type STATCOM are realized, and the positive and negative sequence coordination control of the chain-type STATCOM when the voltage of the power grid is unbalanced is realized by decomposing the device into a positive sequence control part and a negative sequence control part.
The following will explain the basic principle of the positive and negative sequence coordination control method of the chain-type STATCOM when the grid voltage is unbalanced:
the positive and negative sequence coordination control method of the chain-type STATCOM during the unbalanced voltage of the power grid is as follows:
(1) detecting the voltage of a power grid by using a Hall voltage sensor, and detecting the real-time phase theta of the voltage of the power grid through a power grid synchronous phase quick open-loop detection module; phase information of the whole system is provided by a power grid synchronous phase open-loop detection method;
(2) three-phase current i output by STATCOM (static synchronous compensator) detected by Hall current sensorca、icb、iccAnd inputting the positive sequence current i to a positive sequence reactive compensation current calculation module to obtain the positive sequence current i output by the STATCOM under the dq coordinate system+ cd、i+ cq(ii) a The expression of the positive sequence reactive compensation current calculation module is as follows:
(3) three-phase load current i detected by Hall current sensorla、ilb、ilcAnd the output signal of the q axis is used as a positive sequence reactive compensation current instruction value i of the chain type STATCOM device+ qref(ii) a The positive sequence reactive command current calculation formula is as follows:
(4) the direct-current side capacitor voltage values of all power units of the STATCOM are detected by using 3N Hall voltage sensors, input to a global direct-current capacitor voltage control module, and calculated by using a direct-current capacitor voltage control algorithm to obtain a d-axis positive sequence compensation current instruction value i of the chain type STATCOM device+ dref(ii) a The global dc capacitor voltage control algorithm is shown in fig. 3; the basic principle and the steps are as follows: carrying out summation operation u on detected direct current capacitor voltages of 3N H-bridge modulesdc_sumThen, the voltage is added to a DC capacitor voltage command value of 3N timesdc_refAnd performing difference, and finally, calculating the deviation voltage value through a PI regulator to obtain a d-axis positive sequence compensation current instruction value i under the dq coordinate system+ dref(ii) a Wherein the content of the first and second substances,
udc_ai、udc_bi、udc_cithe voltage of the direct current capacitor of each phase ith module in the actually sampled A, B, C three phases is respectively, and N is the number of each phase H-bridge module.
(5) Taking the output current signals of the steps (1) to (4) as input signals of a positive sequence current decoupling control module, and obtaining a positive sequence output voltage instruction value u of the STATCOM device under a dq coordinate system by using a positive sequence current decoupling control algorithm+ cd、u+ cqThe specific calculation formula is as follows:
wherein, U+ cPositive sequence voltage, delta, output by inverter+The positive sequence voltage output by the inverter is ahead of the phase shift angle of the positive sequence voltage of the power grid; the positive sequence current decoupling control algorithm is shown in fig. 4.
(6) The detected power grid voltage and phase theta are subjected to a negative sequence separation module to obtain the negative sequence voltage u of the power grid under the dq coordinate system- sd、u- sqThe specific calculation formula is as follows:
wherein U is- sβ phase difference between negative and positive sequence components for grid negative sequence voltage;
(7) and (4) taking the output signals of the steps (5) and (6) as input signals of a negative sequence voltage calculation module, and further realizing a negative sequence component under a coordination control strategy, wherein a specific calculation formula is as follows:
wherein, U+ cFor positive sequence voltage, U, output by the inverter— sFor the negative sequence voltage of the grid, β is the phase difference between the negative and positive sequence components, δ+The positive sequence voltage output for the inverter leads the phase shift angle of the positive sequence voltage of the grid.
(8) And (4) taking the outputs of the modules in the steps (5) and (7) and the module average voltage direct current control module as input signals of the voltage instruction synthesis and phase-shift carrier modulation module, namely generating PWM control signals of the inverter, so that positive and negative sequence coordination control of the chain-type STATCOM when the power grid voltage is unbalanced is realized.
In addition, a simulation model of the positive and negative sequence coordination control method of the chain-type STATCOM when the power grid voltage is unbalanced is built, simulation verification is carried out on the method, and the simulation result also proves the correctness and the effectiveness of the scheme.
The grid voltage is suddenly increased by 30% of negative sequence component between 0.14s and 0.18s, and the phase difference between the positive sequence component and the negative sequence component is 300(ii) a The result shown in fig. 6 is the current flowing through the device without negative sequence control, fig. 7 is the device current waveform in the positive and negative sequence coordination control mode, fig. 8 is the unbalance degree of the current shown in fig. 7, and fig. 9 is the reactive component of the system current after decomposition in the dq coordinate system at this time. Therefore, under the positive and negative sequence coordination control mode, the negative sequence component of the current flowing through the device is effectively controlled, the current unbalance degree is low, the reactive component of the system current is zero, the disturbance is slight near the disturbance point of the system, and the STATCOM still completes the function of compensating the positive sequence reactive power.
The method provided by the invention has good capacity of coping with the unbalance of the power system, can ensure that the chain type STATCOM device can safely and stably operate under the working conditions of asymmetrical system voltage and phase disturbance, simultaneously meets the requirement of high-performance reactive power compensation, and has good application value.
The above detailed description of the present invention is provided for the purpose of describing particular embodiments thereof, and it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the present invention as defined in the appended claims.
Claims (9)
1. The positive and negative sequence component coordination control system of the chain-type STATCOM when the voltage of a power grid is unbalanced is characterized in that: the system comprises a power grid synchronous phase rapid open-loop detection module, a global direct-current capacitor voltage control module, a positive sequence reactive compensation current calculation module, a positive sequence reactive instruction current calculation module, a positive sequence current decoupling control module, a negative sequence separation module, a negative sequence voltage calculation module, a power module average direct-current voltage control module and a voltage instruction synthesis and phase-shifting carrier modulation module;
the power grid synchronous phase quick open-loop detection module is used for obtaining a real-time phase theta of the power grid voltage according to the power grid voltage detected by the first Hall voltage sensor;
the positive sequence reactive compensation current calculation module is used for detecting the three-phase current i output by the STATCOM according to the first Hall current sensorca、icb、iccObtaining the positive sequence compensation current i output by the STATCOM under the dq coordinate system+ cd、i+ cq；
The positive sequence reactive instruction current calculation module is used for calculating the three-phase load current i detected by the second Hall current sensorla、ilb、ilcAnd taking the signal output by the q axis as a q axis positive sequence reactive compensation current command value i of the chain type STATCOM device+ qref；
The global direct current capacitor voltage control module is used for detecting direct current capacitor voltage of each power unit of the STATCOM according to 3N second Hall voltage sensors, N is the number of power units of each phase, and a direct current capacitor voltage control algorithm is used for obtaining a d-axis positive sequence active compensation current instruction value i of the chained STATCOM device+ dref；
The positive sequence current decoupling control module is used for obtaining a positive sequence output voltage instruction value u of the STATCOM device under a dq coordinate system by using a positive sequence current decoupling control algorithm according to output current signals of the positive sequence reactive compensation current calculation module, the positive sequence reactive instruction current calculation module and the global direct current capacitor voltage control module+ cd、u+ cq；
The negative sequence separation module is used for obtaining the negative sequence voltage u of the power grid under the dq coordinate system according to the detected power grid voltage and the phase theta- sd、u- sq；
The negative sequence voltage calculation module is used for generating a negative sequence component signal under a coordination control strategy according to output voltage signals of the negative sequence separation module and the positive sequence current decoupling control module;
the voltage instruction synthesis and phase-shift carrier modulation module is used for generating a PWM control signal of the inverter according to output signals of the positive sequence current decoupling control module, the negative sequence voltage calculation module and the power module average direct current voltage control module, and performing positive and negative sequence coordination control on the chain-type STATCOM when the voltage of the power grid is unbalanced.
2. A positive and negative sequence coordination control method of a chain type STATCOM when the voltage of a power grid is unbalanced is characterized by comprising the following steps:
(1) detecting the power grid voltage by using a first Hall voltage sensor, and detecting the real-time phase theta of the power grid voltage by using a power grid synchronous phase quick open-loop detection module;
(2) three-phase current i output by STATCOM (static synchronous compensator) is detected by utilizing first Hall current sensorca、icb、iccAnd inputting the positive sequence compensation current i to a positive sequence reactive compensation current calculation module to obtain a positive sequence compensation current i output by the STATCOM under the dq coordinate system+ cd、i+ cq；
(3) Detecting three-phase load current i with a second Hall current sensorla、ilb、ilcAnd the output signal of the q axis is used as a q axis positive sequence reactive compensation current instruction value i of the chain type STATCOM device+ qref；
(4) Detecting the direct-current capacitor voltage of each power unit of the STATCOM by using 3N second Hall voltage sensors, inputting the direct-current capacitor voltage into a global direct-current capacitor voltage control module, wherein N is the number of power units of each phase of the device, and calculating by using a direct-current capacitor voltage control algorithm to obtain a d-axis positive sequence active compensation current instruction value i of the chain type STATCOM+ dref；
(5) Taking the output current signals of the steps (2) to (4) as input signals of a positive sequence current decoupling control module, and obtaining a positive sequence output voltage instruction value u of the STATCOM device under a dq coordinate system by using a positive sequence current decoupling control algorithm+ cd、u+ cq；
(6) The detected power grid voltage and the phase theta thereof are subjected to a negative sequence separation module to obtain the negative sequence voltage u of the power grid under the dq coordinate system- sd、u- sq；
(7) Taking the output signals of the steps (5) and (6) as input signals of a negative sequence voltage calculation module to obtain a negative sequence component under a coordination control strategy;
(8) and (5) taking the output of the average direct current voltage control module of the power modules in the steps (5) and (7) as an input signal of a voltage instruction synthesis and phase-shift carrier modulation module, generating a PWM (pulse width modulation) control signal of the inverter, and performing positive and negative sequence coordination control on the chain-type STATCOM when the voltage of the power grid is unbalanced.
3. The positive and negative sequence coordination control method of the chain-type STATCOM in the case of the unbalanced grid voltage according to claim 2, characterized in that:
in the step (2), the expression of the positive sequence reactive compensation current calculation module is as follows:
4. the positive and negative sequence coordination control method of the chain-type STATCOM in the case of the unbalanced grid voltage according to claim 2, characterized in that:
in the step (3), the positive sequence reactive instruction current calculation module formula is as follows:
5. the positive and negative sequence coordination control method of the chain-type STATCOM in the case of the unbalanced grid voltage according to claim 2, characterized in that:
in the step (4), the detected DC capacitor voltages of the 3N power units are subjected to summation operation udc_sumThen, the voltage is added to a DC capacitor voltage command value of 3N timesdc_refAnd performing difference, and finally calculating the deviation voltage value through a PI (proportional integral) regulator to obtain a d-axis positive sequence active compensation current instruction value i in a dq coordinate system+ dref(ii) a Wherein the content of the first and second substances,
udc_ai、udc_bi、udc_cithe voltage of the direct current capacitor of each ith power unit of each phase in A, B, C actually sampled phases is respectively, and N is the number of the power units of each phase.
6. The positive and negative sequence coordination control method of the chain-type STATCOM in the case of the unbalanced grid voltage according to claim 2, characterized in that:
in the step (5), the positive sequence current decoupling control algorithm specifically calculates the following formula:
wherein, U+ cPositive sequence voltage, delta, output by inverter+The positive sequence voltage output for the inverter leads the phase shift angle of the positive sequence voltage of the grid.
7. The positive and negative sequence coordination control method of the chain-type STATCOM in the case of the unbalanced grid voltage according to claim 2, characterized in that:
in the step (6), the specific calculation formula of the negative sequence separation module is as follows:
wherein, U- sβ phase difference between negative and positive sequence components for grid negative sequence voltage.
8. The positive and negative sequence coordination control method of the chain-type STATCOM in the case of the unbalanced grid voltage according to claim 2, characterized in that:
the calculation formula of the negative sequence voltage calculation module is as follows:
wherein, U+ cFor positive sequence voltage, U, output by the inverter- sFor the negative sequence voltage of the grid, β is the phase difference between the negative and positive sequence components, δ+The positive sequence voltage output for the inverter leads the phase shift angle of the positive sequence voltage of the grid.
9. The positive and negative sequence coordination control method of the chain-type STATCOM in the case of the unbalanced grid voltage according to claim 2, characterized in that: the positive and negative sequence coordination control relationship of the chain-type STATCOM when the voltage of the power grid is unbalanced is as follows:
δ+＝δ-
wherein m is+、m-The modulation ratios of positive sequence voltage and negative sequence voltage, U, respectively, output by the inverter+ s、U- sPositive and negative sequence voltages, delta, of the grid, respectively+The positive sequence voltage output by the inverter leads the phase shift angle, delta, of the positive sequence voltage of the grid-The negative sequence voltage output for the inverter leads the phase shift angle of the negative sequence voltage of the grid.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104362651A (en) * | 2014-11-27 | 2015-02-18 | 哈尔滨理工大学 | Three-phase imbalance downward cascade type H-bridge static synchronous reactive compensation device and compensation method |
| CN104466968A (en) * | 2014-12-24 | 2015-03-25 | 安徽天沃电气技术有限公司 | DSTATCOM negative-sequence current cross coupling compensation control method |
| CN105337281A (en) * | 2015-10-23 | 2016-02-17 | 株洲变流技术国家工程研究中心有限公司 | DC side capacitance voltage control method for star-shaped chained active power filter |
| CN105656056A (en) * | 2016-01-29 | 2016-06-08 | 许继电气股份有限公司 | Mixed voltage-sharing control method of cascaded STATCOM submodules |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI533553B (en) * | 2014-10-21 | 2016-05-11 | 國立清華大學 | Power management method and controller thereof |
-
2018
- 2018-02-10 CN CN201810138597.4A patent/CN108306316B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104362651A (en) * | 2014-11-27 | 2015-02-18 | 哈尔滨理工大学 | Three-phase imbalance downward cascade type H-bridge static synchronous reactive compensation device and compensation method |
| CN104466968A (en) * | 2014-12-24 | 2015-03-25 | 安徽天沃电气技术有限公司 | DSTATCOM negative-sequence current cross coupling compensation control method |
| CN105337281A (en) * | 2015-10-23 | 2016-02-17 | 株洲变流技术国家工程研究中心有限公司 | DC side capacitance voltage control method for star-shaped chained active power filter |
| CN105656056A (en) * | 2016-01-29 | 2016-06-08 | 许继电气股份有限公司 | Mixed voltage-sharing control method of cascaded STATCOM submodules |
Non-Patent Citations (2)
| Title |
|---|
| 大容量链式STATCOM主电路及控制策略的研究;杜明军;《中国优秀硕士学位论文全文数据库》;20121031;第1-91页 * |
| 链式STATCOM控制策略研究;陈启超;《中国优秀硕士学位论文全文数据库》;20131231;第1-92页 * |
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