CN113206504A - Power supply network voltage comprehensive compensation control method based on chain type power electronic converter - Google Patents

Power supply network voltage comprehensive compensation control method based on chain type power electronic converter Download PDF

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CN113206504A
CN113206504A CN202110649210.3A CN202110649210A CN113206504A CN 113206504 A CN113206504 A CN 113206504A CN 202110649210 A CN202110649210 A CN 202110649210A CN 113206504 A CN113206504 A CN 113206504A
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load
current
phase
voltage
component
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何师
孙凯
张海涛
鲁挺
吴丹青
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BEIJING RONGXIN HUIKE TECHNOLOGY CO LTD
Rongxin Huike Electric Co ltd
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BEIJING RONGXIN HUIKE TECHNOLOGY CO LTD
Rongxin Huike Electric Co ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/01—Arrangements for reducing harmonics or ripples
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
    • H02J3/16—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by adjustment of reactive power
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/18—Arrangements for adjusting, eliminating or compensating reactive power in networks
    • H02J3/1821—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators
    • H02J3/1835—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators with stepless control
    • H02J3/1842—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators with stepless control wherein at least one reactive element is actively controlled by a bridge converter, e.g. active filters
    • H02J3/1857—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators with stepless control wherein at least one reactive element is actively controlled by a bridge converter, e.g. active filters wherein such bridge converter is a multilevel converter
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/30—Reactive power compensation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/40—Arrangements for reducing harmonics

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Supply And Distribution Of Alternating Current (AREA)

Abstract

The invention provides a power supply network voltage comprehensive compensation control method based on a three-phase chain type power electronic converter, which is realized by a random load current detection module, a power supply network voltage variation closed-loop control module and a power supply network access point reactive power closed-loop control module. The method comprises the steps that a random load current detection module calculates a harmonic current component, a reactive current component and a current component causing voltage flicker, which are injected into a power grid by a load, the output value of a power supply network voltage change control module and the output value of a power supply network access point reactive power closed-loop control module are superposed into the calculation of the reactive current component, and finally the harmonic current component, the reactive current component and the current component causing voltage flicker, which are injected into the power grid by the load, are added and serve as a total current reference value to be output to a converter current control module, so that the purpose of compensating the voltage of the power supply network is achieved. The power quality problem caused by the load is effectively controlled.

Description

Power supply network voltage comprehensive compensation control method based on chain type power electronic converter
Technical Field
The invention relates to the technical field of power supply quality control of a power supply network, in particular to a power supply network voltage comprehensive compensation control method based on a three-phase chain type power electronic converter.
Background
In the application of the current power electronic system, the H-bridge cascade-type power electronic converter has the advantages of modular structure design, high stability, small occupied area and the like, and occupies most of the market share of the high-voltage power electronic converter.
In the current national production equipment, because novel production equipment is continuously generated, the production efficiency is greatly improved, but the power grid is greatly influenced due to a complex production process, wherein typical random loads comprise electric arc furnace loads, rolling mills and the like. Particularly in the modern steel industry, a large amount of electric arc furnace steelmaking processes are adopted, the electric arc furnace loads belong to typical random loads, the problems of large amount of idle work, harmonic waves, voltage flicker, negative sequence and the like can be brought to a power grid, and the random loads have increasingly large influence on the power grid.
Disclosure of Invention
In order to solve the technical problems provided by the background technology, the invention provides a load compensation control method suitable for an H-bridge cascaded power electronic converter, and provides a comprehensive compensation control method of voltage flicker, power factor and harmonic current based on a mature three-phase H-bridge unit cascaded converter.
In order to achieve the purpose, the invention adopts the following technical scheme:
a supply network voltage comprehensive compensation control method based on a three-phase chain type power electronic converter is realized by a random load current detection module, a supply network voltage variation closed-loop control module and a supply network access point reactive power closed-loop control module.
The method comprises the steps that a random load current detection module calculates a harmonic current component, a reactive current component and a current component causing voltage flicker, which are injected into a power grid by a load, the output value of a power supply network voltage change amount control module and the output value of a power supply network access point reactive power closed-loop control module are superposed into the calculation of the reactive current component, and finally the harmonic current component, the reactive current component and the current component causing voltage flicker, which are injected into the power grid by the load, are added and serve as a total current reference value to be output to a current control module of an H-bridge cascade power electronic converter, so that the purpose of compensating the voltage of the power supply network is achieved.
Further, the control method in the random load current detection module includes the following steps:
1) firstly, sampling value I of line current of random loadload_A、Iload_B、Iload_CPerforming per unit processing to obtain per unit value I of load currentload_Apu、Iload_Bpu、Iload_CpuTaking a rated line current effective value Isn of the H-bridge cascade type power electronic converter device as a per-unit basic value; clark conversion is carried out on the per unit value of the three-phase line current of the load, the current value under the ABC coordinate is converted into an alpha beta coordinate system, and the alpha-axis component I of the load current is obtainedload_AlfaAnd a beta axis component Iload_Beta；
2) For the detection of the reactive current component, the phase voltage phase (50Hz alternating current component) of the random load power supply is adopted, the line current is subjected to Park conversion, and the current value under the alpha and beta coordinate is changed into the current value I under the DQ coordinateload_D1And Iload_Q1Because the H-bridge cascade converter has no active power generating device, the active current component I is not eliminatedload_D1Compensating for reactive current component I in DQ coordinateload_Q1Filtering to remove AC component to obtain filtered reactive current component Iload_Q1POutput value I of the closed-loop control module, plus the supply network voltage variationRef_UAnd the current reference value I output by the reactive power closed-loop control module of the access pointref_QFinally, the phase voltage phase (50Hz alternating current component) supplied with power by the random load is adopted to carry out inverse Park transformation on the phase voltage phase, and the obtained result Iload_DS1And Iload_QS1I.e. the reactive component in the random load line current;
3) for the detection of the harmonic current component injected into the power grid by the load, the Park transformation is carried out by adopting the phase of multiple angular velocity, namely the integral multiple component of 50Hz, which is obtained by calculating the phase voltage phase of the random load, the current value under the alpha and beta coordinate is changed into the current value under the DQ coordinate, and I is obtainedload_D2～Iload_D4And Iload_Q2～Iload_Q4Then, D, Q current components are respectively filtered, alternating current components in the current components are filtered, finally, inverse Park transformation is carried out on the phase of the angular velocity with multiple times obtained by phase voltage phase calculation of random load, and a result I is obtainedload_DS2～Iload_DS4And Iload_QS2～Iload_QS4I.e. the harmonic component in the random load line current;
4) for the detection of current component causing voltage flicker, a subsynchronous phase calculated by a phase voltage phase of random load power supply, namely a 25Hz alternating current component is adopted, line current is subjected to Park conversion, and a current value under an alpha and beta coordinate is converted into a current value under a DQ coordinate to obtain Iload_DsAnd Iload_Qs(ii) a Then to Iload_DsAnd Iload_QsFiltering the current components respectively to filter out the AC components therein to obtain Iload_DsPAnd Iload_QsPFinally, the subsynchronous phase calculated by the phase voltage phase of the random load power supply is adopted to carry out reverse Park conversion on the line current of the subsynchronous phase to obtain Iload_DSsAnd Iload_QSsTo obtainA flicker component into the random loadline current;
after the calculation, adding the results obtained in 2), 3) and 4) to obtain the component I of the total load current in the alpha beta coordinate systemload_Alfa_sAnd Iload_Beta_sAnd performing reverse Clark conversion to obtain the total load current calculated value Ifref_A、Ifref_B、Ifref_CThe reference value is output to a current control module of the H-bridge cascaded power electronic converter as a total current reference value, so that the purpose of compensating the voltage of a power supply network is achieved.
Furthermore, the phase and the subsynchronous phase of the multiple angular velocity of the random load are obtained by a phase-locked loop (PLL) from the three-phase supply voltage of the random load, and then the phase and the subsynchronous phase of the multiple angular velocity are obtained by trigonometric function calculation.
Further, the control method of the supply network voltage variation closed-loop control module comprises the following steps:
collecting bus voltage U of power supply networkHVThen calculate its effective value UHV_rmsThen using the rated voltage effective value UnPerforming per unit processing to obtain per unit value U of bus voltage of the power supply networkHV_puFiltering the DC component of the voltage signal by a high-pass filter to obtain a voltage error value UHV_errFinally, obtaining the output value I of the reference value of the partial current after passing through a proportional-derivative regulatorRef_U。
Further, the control method of the power supply network access point reactive power closed-loop control module comprises the following steps:
collecting the current I of the bus access pointHVThen calculating its effective value IHV_rmsAnd current value I according to rated capacity of access pointnPerforming per unit treatment to obtain per unit value I of the currentHV_puAnd simultaneously, the voltage per unit value U obtained in the voltage variable closed-loop control is utilizedHV_puCalculating reactive power Q at system access pointHV_puThe reference value I of the reactive current of the system is obtained after the reference value I of the reactive current of the system is processed by a proportional-integral regulatorref_Q。
Compared with the prior art, the invention has the beneficial effects that:
1) the invention provides a multi-angular speed coordinate transformation mode based on a mature H-bridge cascade power electronic converter, avoids the alternating current quantity phase detection error of the traditional current detection method, achieves the high-precision control effect and stabilizes the power supply quality of a power grid.
2) The invention provides a comprehensive compensation control method of voltage flicker, power factor and harmonic current based on a mature three-phase H-bridge unit cascade converter, which effectively controls the problem of electric energy quality caused by load and improves the power supply quality of a power grid.
3) On the basis of compensating higher harmonic current, the invention simultaneously considers 50Hz reactive current compensation of power frequency and flicker current in the frequency range below 50 Hz.
Drawings
FIG. 1 is a topology diagram of a three-phase H-bridge cascaded power electronic converter system and its controller of the present invention;
FIG. 2 is a topological diagram (star connection) of a three-phase H-bridge power unit cascaded power electronic converter of the invention;
FIG. 3 is a topological diagram of a three-phase H-bridge power unit cascade power electronic converter (angle joint)
FIG. 4 is a block diagram of the voltage flicker, reactive power and harmonic synthesized compensation control of the present invention;
FIG. 5 is a block diagram of the polygon velocity voltage rotation vector calculation of the present invention.
Detailed Description
The following detailed description of the present invention will be made with reference to the accompanying drawings.
The topology of the power electronic converter with a three-phase H-bridge unit cascade structure is shown in fig. 1, and for explaining the content of the invention, it is assumed that a random load is connected to a power supply network through a step-up transformer in a working condition, and the power electronic converter is connected in parallel with the power random load for compensation. For the power supply network, the meaning of load compensation refers to the compensation of the power quality problem caused by the load by using corresponding equipment, and the compensation comprises the problems of power supply network voltage flicker, power supply network reactive power, harmonic wave and the like.
The topological graph of the three-phase H-bridge power unit cascade power electronic converter is divided into a star topology (as shown in figure 2) and an angle topology (as shown in figure 3)
As shown in fig. 4, a supply network voltage comprehensive compensation control method based on a three-phase chain type power electronic converter is implemented by a random load current detection module, a supply network voltage variation closed-loop control module and a supply network access point reactive power closed-loop control module.
The random load current detection module calculates the harmonic current component I injected into the power grid by the loadload_DS2～Iload_DS4And Iload_QS2～Iload_QS4Reactive current component Iload_DS1And Iload_QS1And a current component I which causes voltage flickerload_DSsAnd Iload_QSsControlling the output value I of the module by controlling the voltage variation of the power supply networkRef_UAnd the current reference value I output by the reactive power closed-loop control module of the access pointref_QSuperimposed on the reactive current component Iload_DS1And Iload_QS1In the calculation of (1), the harmonic current component, the reactive current component and the current component causing voltage flicker injected by the load to the power grid are added to be used as a total current reference value Ifref_A、Ifref_B、Ifref_CAnd the voltage is output to a current control module of the H-bridge cascaded power electronic converter, so that the purpose of compensating the voltage of a power supply network is achieved.
1) Detection of harmonic current components
In a harmonic component detection module of the random load, the control method detects second, third and fourth harmonic components in a current component of the random load. The method mainly comprises the steps of carrying out frequency multiplication on the power supply voltage of the load to obtain a frequency multiplication rotating vector higher than the power frequency, and then orienting the load current according to the frequency multiplication vector of the power supply voltage of the random load to obtain the amplitude of each subharmonic to carry out load compensation. The traditional harmonic detection method has phase lag of detection components after filtering harmonic components, and the invention mainly converts each secondary component into direct current quantity, thereby avoiding the possibility of phase error.
2) Detection of flicker current component
The flicker component is defined as an alternating current component below 50Hz power frequency, mainly concentrated around 25 Hz. The method provides a method for converting a power frequency vector of voltage into a subsynchronous 25Hz rotating vector, and simultaneously, the current of a random load is oriented by using the subsynchronous 25Hz rotating vector, and the detected direct current component is used as a given value for compensation, so that the phase error caused by low-pass filtering is avoided.
3) Detection of reactive current components
For the 50Hz reactive component of the power frequency, the method orients the random load current according to the rotating vector of the load power supply voltage, thereby obtaining the reactive current component of the load.
The method also comprises a power supply network voltage variation closed-loop control module and a power supply network access point reactive power closed-loop control module, and compared with the traditional load compensation control strategy, the method fundamentally solves the problem of phase lag caused by current detection.
As shown in fig. 4, the control method in the random load current detection module includes the following steps:
1) firstly, sampling value I of line current of random loadload_A、Iload_B、Iload_CPerforming per unit processing to obtain per unit value I of load currentload_Apu、Iload_Bpu、Iload_CpuTaking a rated line current effective value Isn of the H-bridge cascade type power electronic converter device as a per-unit basic value; clark conversion is carried out on the per unit value of the three-phase line current of the load, the current value under the ABC coordinate is converted into an alpha beta coordinate system, and the alpha-axis component I of the load current is obtainedload_AlfaAnd a beta axis component Iload_Beta；
2) For the detection of the reactive current component, the phase voltage phase (50Hz alternating current component) of the random load power supply is adopted, the line current is subjected to Park conversion, and the current value under the alpha and beta coordinate is changed into the current value I under the DQ coordinateload_D1And Iload_Q1Because of the H-bridge cascade converterNo active power generating device, so that no active current component I is involvedload_D1Compensating for reactive current component I in DQ coordinateload_Q1Filtering to remove AC component to obtain filtered reactive current component Iload_Q1POutput value I of the closed-loop control module, plus the supply network voltage variationRef_UAnd the current reference value I output by the reactive power closed-loop control module of the access pointref_QFinally, the phase voltage phase (50Hz alternating current component) supplied with power by the random load is adopted to carry out inverse Park transformation on the phase voltage phase, and the obtained result Iload_DS1And Iload_QS1I.e. the reactive component in the random load line current;
3) for the detection of the harmonic current component injected into the power grid by the load, the Park transformation is carried out by adopting the phase of multiple angular velocity, namely the integral multiple component of 50Hz, which is obtained by calculating the phase voltage phase of the random load, the current value under the alpha and beta coordinate is changed into the current value under the DQ coordinate, and I is obtainedload_D2～Iload_D4And Iload_Q2～Iload_Q4Then, D, Q current components are respectively filtered, alternating current components in the current components are filtered, finally, inverse Park transformation is carried out on the phase of the angular velocity with multiple times obtained by phase voltage phase calculation of random load, and a result I is obtainedload_DS2～Iload_DS4And Iload_QS2～Iload_QS4I.e. the harmonic component in the random load line current;
4) for the detection of current component causing voltage flicker, a subsynchronous phase calculated by a phase voltage phase of random load power supply, namely a 25Hz alternating current component is adopted, line current is subjected to Park conversion, and a current value under an alpha and beta coordinate is converted into a current value under a DQ coordinate to obtain Iload_DsAnd Iload_Qs(ii) a Then to Iload_DsAnd Iload_QsFiltering the current components respectively to filter out the AC components therein to obtain Iload_DsPAnd Iload_QsPFinally, the subsynchronous phase calculated by the phase voltage phase of the random load power supply is adopted to carry out reverse Park conversion on the line current of the subsynchronous phase to obtain Iload_DSsAnd Iload_QSsObtaining a flicker component in the random load line current;
after the calculation, adding the results obtained in 2), 3) and 4) to obtain the component I of the total load current in the alpha beta coordinate systemload_Alfa_sAnd Iload_Beta_sAnd performing reverse Clark conversion to obtain the total load current calculated value Ifref_A、Ifref_B、Ifref_CThe reference value is output to a current control module of the H-bridge cascaded power electronic converter as a total current reference value, so that the purpose of compensating the voltage of a power supply network is achieved.
The Clark transformation, inverse Clark transformation, Park transformation and inverse Park transformation formulas used in this section are as follows:
clark transformation:
Figure BDA0003110470000000061
the variable meanings for this section are as follows:
Uα: a component of the transformed alpha axis;
Uβ: a component of the transformed β -axis;
Ua: a phase a component before transformation;
Ub: a pre-transformation B-phase component;
Uc: a pre-transformation C-phase component;
anti-Clark transformation:
Figure BDA0003110470000000062
the variable meanings for this section are as follows:
Uα: the component of the alpha axis before transformation;
Uβ: a component of the beta axis before transformation;
Ua: a transformed a-phase component;
Ub: a transformed B-phase component;
Uc: a transformed C-phase component;
park transformation:
Figure BDA0003110470000000071
the variable meanings for this section are as follows:
Uα: the component of the alpha axis before transformation;
Uβ: a component of the beta axis before transformation;
Ud: a transformed D-axis component;
Uq: a transformed Q-axis component;
cos θ: transforming the phase used;
sin θ: transforming the applied quadrature phase;
inverse Park transformation:
Figure BDA0003110470000000072
the variable meanings for this section are as follows:
Uα: a component of the transformed alpha axis;
Uβ: a component of the transformed β -axis;
Ud: a D-axis component before transformation;
Uq: a Q-axis component before transformation;
cos θ: transforming the phase used;
sin θ: transforming the applied quadrature phase;
the Low Pass Filter (LPF) transfer function used is:
Figure BDA0003110470000000073
the variable meanings for this section are as follows:
s: a transfer function frequency domain operator;
An: filter passband gain;
ωn: transfer letterSeveral shear frequencies;
ζ: a filter damping coefficient.
The method for calculating the polygon velocity voltage rotation vector is shown in fig. 5, wherein the phase of the multiple angular velocity and the subsynchronous phase of the random load are obtained by a phase-locked loop PLL from the three-phase power supply voltage of the random load to obtain the phase of the 50Hz alternating current component, and then the phase of the multiple angular velocity and the subsynchronous phase are obtained by trigonometric function calculation.
As shown in fig. 4, the control method of the supply network voltage variation closed-loop control module includes the following steps:
collecting bus voltage U of power supply networkHVThen calculate its effective value UHV_rmsThen using the rated voltage effective value UnPerforming per unit processing to obtain per unit value U of bus voltage of the power supply networkHV_puFiltering the DC component of the voltage signal by a high-pass filter to obtain a voltage error value UHV_errFinally, obtaining the output value I of the reference value of the partial current after passing through a proportional-derivative regulatorRef_U。
The high pass filter transfer function and the proportional derivative regulator transfer function used in this section are as follows:
the transfer function of the high-pass filter is:
Figure BDA0003110470000000081
the variable meanings for this section are as follows:
s: a transfer function frequency domain operator;
An: filter passband gain;
ωn: a transfer function shear frequency;
ζ: a filter damping coefficient;
the transfer function of the high-pass filter is: g (S) ═ Kp+KdS
S: a transfer function frequency domain operator;
Kp: a regulator scaling factor;
Kd: the regulator differential coefficient.
As shown in fig. 4, the control method of the reactive power closed-loop control module of the power supply network access point includes the following steps:
collecting the current I of the bus access pointHVThen calculating its effective value IHV_rmsAnd current value I according to rated capacity of access pointnPerforming per unit treatment to obtain per unit value I of the currentHV_puAnd simultaneously, the voltage per unit value U obtained in the voltage variable closed-loop control is utilizedHV_puCalculating reactive power Q at system access pointHV_puThe reference value I of the reactive current of the system is obtained after the reference value I of the reactive current of the system is processed by a proportional-integral regulatorref_Q。
The PI regulator transfer function used by this section is as follows:
PI regulator transfer function:
Figure BDA0003110470000000082
s: a transfer function frequency domain operator;
Kp: a regulator scaling factor;
KI: the regulator integration coefficient.
The above embodiments are implemented on the premise of the technical solution of the present invention, and detailed embodiments and specific operation procedures are given, but the scope of the present invention is not limited to the above embodiments. The methods used in the above examples are conventional methods unless otherwise specified.

Claims (5)

1. A supply network voltage comprehensive compensation control method based on a three-phase chain type power electronic converter is characterized in that the method is realized by a random load current detection module, a supply network voltage variation closed-loop control module and a supply network access point reactive power closed-loop control module;
the method comprises the steps that a random load current detection module calculates a harmonic current component, a reactive current component and a current component causing voltage flicker, which are injected into a power grid by a load, the output value of a power supply network voltage change amount control module and the output value of a power supply network access point reactive power closed-loop control module are superposed into the calculation of the reactive current component, and finally the harmonic current component, the reactive current component and the current component causing voltage flicker, which are injected into the power grid by the load, are added and serve as a total current reference value to be output to a current control module of an H-bridge cascade power electronic converter, so that the purpose of compensating the voltage of the power supply network is achieved.
2. A supply network voltage comprehensive compensation control method based on a three-phase chain type power electronic converter according to claim 1, characterized in that the control method in the random load current detection module comprises the following steps:
1) firstly, sampling value I of line current of random loadload_A、Iload_B、Iload_CPerforming per unit processing to obtain per unit value I of load currentload_Apu、Iload_Bpu、Iload_CpuTaking a rated line current effective value Isn of the H-bridge cascade type power electronic converter device as a per-unit basic value; clark conversion is carried out on the per unit value of the three-phase line current of the load, the current value under the ABC coordinate is converted into an alpha beta coordinate system, and the alpha-axis component I of the load current is obtainedload_AlfaAnd a beta axis component Iload_Beta；
2) For the detection of the reactive current component, the phase voltage phase (50Hz alternating current component) of the random load power supply is adopted, the line current is subjected to Park conversion, and the current value under the alpha and beta coordinate is changed into the current value I under the DQ coordinateload_D1And Iload_Q1Because the H-bridge cascade converter has no active power generating device, the active current component I is not eliminatedload_D1Compensating for reactive current component I in DQ coordinateload_Q1Filtering to remove AC component to obtain filtered reactive current component Iload_Q1POutput value I of the closed-loop control module, plus the supply network voltage variationRef_UAnd the current reference value I output by the reactive power closed-loop control module of the access pointref_QFinally, the phase voltage phase (50Hz alternating current component) supplied with power by the random load is adopted to carry out inverse Park transformation on the phase voltage phase, and the obtained result Iload_DS1And Iload_QS1I.e. the reactive component in the random load line current;
3) for the detection of the harmonic current component injected into the power grid by the load, the Park transformation is carried out by adopting the phase of multiple angular velocity, namely the integral multiple component of 50Hz, which is obtained by calculating the phase voltage phase of the random load, the current value under the alpha and beta coordinate is changed into the current value under the DQ coordinate, and I is obtainedload_D2～Iload_D4And Iload_Q2～Iload_Q4Then, D, Q current components are respectively filtered, alternating current components in the current components are filtered, finally, inverse Park transformation is carried out on the phase of the angular velocity with multiple times obtained by phase voltage phase calculation of random load, and a result I is obtainedload_DS2～Iload_DS4And Iload_QS2～Iload_QS4I.e. the harmonic component in the random load line current;
4) for the detection of current component causing voltage flicker, a subsynchronous phase calculated by a phase voltage phase of random load power supply, namely a 25Hz alternating current component is adopted, line current is subjected to Park conversion, and a current value under an alpha and beta coordinate is converted into a current value under a DQ coordinate to obtain Iload_DsAnd Iload_Qs(ii) a Then to Iload_DsAnd Iload_QsFiltering the current components respectively to filter out the AC components therein to obtain Iload_DsPAnd Iload_QsPFinally, the subsynchronous phase calculated by the phase voltage phase of the random load power supply is adopted to carry out reverse Park conversion on the line current of the subsynchronous phase to obtain Iload_DSsAnd Iload_QSsObtaining a flicker component in the random load line current;
after the calculation, adding the results obtained in 2), 3) and 4) to obtain the component I of the total load current in the alpha beta coordinate systemload_Alfa_sAnd Iload_Beta_sAnd performing reverse Clark conversion to obtain the total load current calculated value Ifref_A、Ifref_B、Ifref_CThe reference value is output to a current control module of the H-bridge cascaded power electronic converter as a total current reference value, so that the purpose of compensating the voltage of a power supply network is achieved.
3. The method as claimed in claim 2, wherein the phase of the multiple angular velocity and the sub-synchronous phase of the random load are obtained by a phase-locked loop PLL of the three-phase supply voltage of the random load to obtain the phase of the 50Hz ac component, and then the phase of the multiple angular velocity and the sub-synchronous phase are obtained by a trigonometric function calculation.
4. The method for controlling the comprehensive compensation of the voltage of the power supply network based on the three-phase chain-type power electronic converter according to claim 1, wherein the method for controlling the closed-loop control module for the voltage variation of the power supply network comprises the following steps:
collecting bus voltage U of power supply networkHVThen calculate its effective value UHV_rmsThen using the rated voltage effective value UnPerforming per unit processing to obtain per unit value U of bus voltage of the power supply networkHV_puFiltering the DC component of the voltage signal by a high-pass filter to obtain a voltage error value UHV_errFinally, obtaining the output value I of the reference value of the partial current after passing through a proportional-derivative regulatorRef_U。
5. The method for controlling the comprehensive compensation of the voltage of the power supply network based on the three-phase chain-type power electronic converter according to claim 1, wherein the method for controlling the reactive power closed-loop control module of the power supply network access point comprises the following steps:
collecting the current I of the bus access pointHVThen calculating its effective value IHV_rmsAnd current value I according to rated capacity of access pointnPerforming per unit treatment to obtain per unit value I of the currentHV_puAnd simultaneously, the voltage per unit value U obtained in the voltage variable closed-loop control is utilizedHV_puCalculating reactive power Q at system access pointHV_puThe reference value I of the reactive current of the system is obtained after the reference value I of the reactive current of the system is processed by a proportional-integral regulatorref_Q。
CN202110649210.3A 2021-06-10 2021-06-10 Power supply network voltage comprehensive compensation control method based on chain type power electronic converter Pending CN113206504A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116565916A (en) * 2023-07-07 2023-08-08 中国电力科学研究院有限公司 Response method and device for participation of converter load equipment in power grid balance adjustment

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116565916A (en) * 2023-07-07 2023-08-08 中国电力科学研究院有限公司 Response method and device for participation of converter load equipment in power grid balance adjustment
CN116565916B (en) * 2023-07-07 2023-12-15 中国电力科学研究院有限公司 Response method and device for participation of converter load equipment in power grid balance adjustment

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