KR101767451B1 - A control method to improve transient performance of hvdc system and an inverter control apparatus of hvdc system - Google Patents

A control method to improve transient performance of hvdc system and an inverter control apparatus of hvdc system Download PDF

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KR101767451B1
KR101767451B1 KR1020150167414A KR20150167414A KR101767451B1 KR 101767451 B1 KR101767451 B1 KR 101767451B1 KR 1020150167414 A KR1020150167414 A KR 1020150167414A KR 20150167414 A KR20150167414 A KR 20150167414A KR 101767451 B1 KR101767451 B1 KR 101767451B1
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inverter
rectifier
angle
constant current
control mode
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KR1020150167414A
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Korean (ko)
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KR20170062055A (en
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김학만
손호익
송민석
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인천대학교 산학협력단
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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
    • H02J1/00—Circuit arrangements for dc mains or dc distribution networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H02M2001/0006—
    • 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
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]

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  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

A control method for improving the transient performance of the HVDC system according to an embodiment of the present invention includes the steps of: (a) controlling a drive of an inverter of a high voltage direct current (HVDC) system, Determining whether a rectifier of the HVDC system is operating in a constant current control mode; (b) if the rectifier operates in the constant current control mode, determining in the control unit whether the inverter operates in a constant current control mode; And (c) when the rectifier and the inverter operate in the constant current control mode, increasing the SOHO angle command value applied to the subject flush angle controller in the inverter control apparatus by a predetermined SOHO correction value, HVDC system can reduce the inverter output and AC voltage fluctuation in the process of recovery after failure of AC system on the rectifier side and can shorten transient time which is the arrival time to steady state.

Description

TECHNICAL FIELD [0001] The present invention relates to a control method for enhancing transient performance of an HVDC system and an inverter control apparatus for an HVDC system,

The present invention relates to a HVDC (High Voltage Direct Current), and more particularly, to a control method for improving the transient performance of an HVDC system and an inverter control apparatus for an HVDC system.

The HVDC system has many advantages such as low cost and high power transmission compared to HVAC system in long distance transmission, and its application is increasing. The application of the HVDC system to the power transmission system for linkage is expected to increase.

On the other hand, due to many applications of the HVDC system, much research has been conducted on a method of operating the HVDC system more stably

Particularly, when the HVDC system is recovered according to the recovery characteristic of a conventional HVDC system due to instability of the AC system on the rectifier side in a transient state in which the HVDC system is recovered after a fault occurs from the occurrence of a fault on the rectifier side AC system, It may take some time for the output of the inverter and the voltage fluctuation of the AC system to recover to a normal state. In this case, power can not be supplied to the AC system on the inverter side quickly and stably.

Therefore, there is a need for a method for improving the performance of the HVDC system, which is a process of recovering after an AC system failure, when the AC system becomes unstable due to the failure of the AC system on the rectifier side.

In the following Patent Document 1, the possibility of rectification failure due to the phase shift of the voltage due to the AC system voltage fluctuation is mathematically analyzed and applied to the SOHO angle controller so that the control operation is robust against the rectification failure momentarily, Discloses a soho angle control device for preventing failure and preventing failure of rectification of an HVDC system that improves recovery characteristics after a failure of rectification.

KR 10-2014-0036797 A

The problem to be solved by the present invention is that the HVDC system can reduce the voltage fluctuation of the inverter output and the AC system in the process of recovering after the failure of the AC system on the rectifier side and can reduce the transient time And a control method for improving transient performance of the HVDC system that can be shortened.

Another problem to be solved by the present invention is to reduce the voltage fluctuation of the inverter output and the AC system in the process of recovering the HVDC system after occurrence of a fault in the AC system on the rectifier side, And to provide an inverter control apparatus of an HVDC system capable of shortening the transient time.

According to an aspect of the present invention, there is provided a control method for improving transient performance of an HVDC system,

(a) determining whether a rectifier of the HVDC system operates in a constant current control mode, in a control unit of an inverter control apparatus for controlling operation of an inverter of a high voltage direct current (HVDC) system;

(b) if the rectifier operates in the constant current control mode, determining in the control unit whether the inverter operates in a constant current control mode; And

(c) when the rectifier and the inverter operate in the constant current control mode, the control unit increases the SOHO angle command value applied to the subject flush angle controller in the inverter control apparatus by a predetermined SOHO correction value.

In the control method for the transient performance improvement of the HVDC system according to an embodiment of the present invention, the step (a)

(a-1) obtaining, at the control unit, a rectifier-side firing angle and a rectifier-side minimum firing angle from a rectifier control unit for controlling the operation of the rectifier; And

(a-2) The control unit compares the rectifier-side firing angle and the rectifier-side minimum firing angle, and when the rectifier-side firing angle is larger than the rectifier-side minimum firing angle, the rectifier operates in the constant current control mode And a step of judging.

In the control method for improving the transient performance of the HVDC system according to an embodiment of the present invention, in the step (b)

When the sum of the overlap angle and the soot angle output by the inverter constant current control is greater than the sum of the overlap angle and the soot angle output by the constant extinction angle control of the inverter, As shown in FIG.

In addition, in the step (a), it is determined that the rectifier of the HVDC system does not operate in the constant current control mode, or the step (b) The control unit may further include a step of, when it is determined that the inverter is not operated in the constant current control mode, the control unit retaining the command value as the initial command value.

According to another aspect of the present invention, there is provided an inverter control apparatus for an HVDC system,

A constant current control unit for controlling a current of an inverter of a high voltage direct current (HVDC) system;

A cancellation angle control unit for controlling the soot angle of the inverter;

A control mode selecting unit for selecting a control mode of the inverter based on the output of the constant current control unit and the output of the instantaneous whistle control unit and outputting the firing angle of the inverter according to the selected control mode; And

And a control unit for adjusting an SOHO angle command value applied to the subject's whistle control unit,

Wherein,

(a) determining whether the rectifier of the HVDC system is operating in a constant current control mode,

(b) determining whether the inverter operates in a constant current control mode when the rectifier operates in a constant current control mode; And

(c) When the rectifier and the inverter operate in the constant current control mode, the operation of increasing the small angle command value to be applied to the small side small angle controller is increased by a predetermined small angle correction value.

In the inverter control apparatus for an HVDC system according to an embodiment of the present invention, the operation (a)

(a-1) obtaining a rectifier side firing angle and a rectifier side minimum firing angle from a rectifier control unit for controlling the operation of the rectifier; And

(a-2) comparing the rectifier-side firing angle and the rectifier-side minimum firing angle to determine that the rectifier operates in the constant current control mode when the rectifier-side firing angle is larger than the rectification-side minimum firing angle . ≪ / RTI >

Further, in the inverter control apparatus for an HVDC system according to an embodiment of the present invention, in the operation (b), when the sum of the overlapping angle and the so-called angle outputted by the inverter-side constant current control is equal to the constant extinction angle of the inverter, The control unit may determine that the inverter operates in the constant current control mode if the sum of the overlap angle and the small angle is greater than the sum of the overlap angle and the small angle.

In the inverter control apparatus for an HVDC system according to an embodiment of the present invention, in the operation (a), the rectifier of the HVDC system does not operate in the constant current control mode, or the rectifier in the operation (b) The control unit may further perform the operation of maintaining the SOHO angle instruction value as the initial SOHO angle instruction value.

According to the control method for improving the transient performance of the HVDC system and the inverter control apparatus of the HVDC system according to the embodiment of the present invention, the HVDC system is relatively recovered after the failure of the AC system on the rectifier side, The voltage fluctuation of the AC system can be reduced and the transient time which is the arrival time to the steady state can be shortened.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating a configuration of an exemplary HVDC system to which a control method for improving transient performance of an HVDC system according to an embodiment of the present invention is applied; FIG.
FIG. 2 is a voltage-current characteristic graph showing operation characteristics of an HVDC system by a conventional control operation of a rectifier and an inverter in an HVDC system.
FIG. 3 is a graph of a voltage-current characteristic of an HVDC system using a control method for improving transient performance of an HVDC system according to an exemplary embodiment of the present invention.
4 is a block diagram of an inverter control apparatus to which a control method for improving transient performance of an HVDC system according to an embodiment of the present invention is applied.
5 is a flowchart illustrating a control method for improving transient performance of an HVDC system according to an embodiment of the present invention.
6 is a flow chart showing a control method for improving transient performance of an HVDC system according to an embodiment of the present invention.
FIG. 7 is a graph showing the relationship between the sum of the overlap angle and the small angle of the inverter side, the dotted angle of the rectifier side, and the small angle command value of the inverter side before the control method for improving transient performance of the HVDC system according to the embodiment of the present invention is applied FIG.
FIG. 8 is a graph showing the relationship between the overlap angle and the soot angle on the inverter side, the dotted line angle on the rectifier side, and the Soode angle set value on the inverter side after the control method for improving transient performance of the HVDC system according to the embodiment of the present invention is applied A graph.
9 is a graph showing AC voltage on the rectifier side and AC voltage on the inverter side before applying the control method for improving transient performance of the HVDC system according to an embodiment of the present invention.
10 is a graph showing an AC voltage on the rectifier side and an AC voltage on the inverter side after the control method for improving the transient performance of the HVDC system according to the embodiment of the present invention is applied.
11 is a graph showing the output power of the inverter before and after applying the control method for improving transient performance of the HVDC system according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The objectives, specific advantages and novel features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG.

Prior to that, terms and words used in the present specification and claims should not be construed in a conventional and dictionary sense, and the inventor may properly define the concept of the term in order to best explain its invention Should be construed in accordance with the principles and the meanings and concepts consistent with the technical idea of the present invention.

It should be noted that, in the present specification, the reference numerals are added to the constituent elements of the drawings, and the same constituent elements are assigned the same number as much as possible even if they are displayed on different drawings.

Also, the terms "first", "second", "one side", "other side", etc. are used to distinguish one element from another, It is not.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description of the present invention, a detailed description of known arts which may unnecessarily obscure the gist of the present invention will be omitted.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating a configuration of an HVDC system to which a control method for improving transient performance of an HVDC system according to an embodiment of the present invention is applied.

The HVDC system shown in Figure 1 includes a rectifier 100 connected to an AC system 110 and an inverter 102 connected to another AC system 112 and the output of the rectifier 100 is connected to the transmission line 108 To the inverter 102 via the inverter.

On the other hand, the operation of the rectifier 100 is controlled by the rectifier control unit 104, the operation of the inverter 102 is controlled by the inverter control unit 106, the rectifier control unit 104 and the inverter control unit 106 control the communication line Lt; / RTI >

In the HVDC system in which a control method for improving the transient performance of the HVDC system according to an embodiment of the present invention shown in FIG. 1 is applied, the rectifier 100 is composed of a 12-pulse rectifier, And a 12-pulse inverter.

2 is a graph of voltage-current characteristics showing the operating characteristics of the HVDC system by the conventional control operation of the rectifier 100 and the inverter 102 in the HVDC system.

Generally, in the normal state, the rectifier 100 side can perform a constant current (CC) control operation and a CIA (Constant Ignition Angle) control operation, and the inverter 102 side can control the constant current (CC) CEA: Constant Extinction Angle) control operation is possible.

In the HVDC system, the rectifier 100 operates in a constant current (CC) control mode and maintains a constant current in the steady state. The inverter 102 operates in a constant excitation (CEA) control mode, .

E, which is an intersection of the characteristics of the rectifier 100 and the characteristics of the inverter 102, is determined as the operating point of the HVDC system due to the CC control operation on the rectifier 100 side and the CEA control operation on the inverter 102 side as described above HVDC is operated.

However, when the AC system 110 voltage is lowered due to the failure of the AC system 110 on the rectifier 100 side and the DC voltage on the rectifier 100 is decreased, a control mode change occurs in which the operation point shifts. If the voltage is decreased by ΔV dc as shown in the figure, the control point is shifted from E to E '. Then, the DC point is recovered and the operation point is shifted to E' → G → E The operating point of the state is recovered.

However, when the voltage on the inverter 102 side is recovered first and then the current is recovered as described above, the voltage fluctuation of the inverter output and the AC system becomes relatively large in the process of recovery after occurrence of the fault of the AC system, The transient time, which is the arrival time of the vehicle, can be prolonged.

FIG. 3 is a graph of a voltage-current characteristic of an HVDC system using a control method for improving transient performance of an HVDC system according to an exemplary embodiment of the present invention.

In the control method for improving the transient performance of the HVDC system according to the embodiment of the present invention, the operation characteristics of the HVDC system by the normal control operation of the rectifier 100 and the inverter 102 in the HVDC system shown in FIG. In the process of recovering the DC voltage, the DC voltage on the inverter 102 side is instantaneously lowered to recover the DC current, and then the DC voltage on the inverter 102 is recovered to finally obtain the steady state operating point .

This operation can be confirmed from FIG. 3, and unlike the normal operation characteristic of recovering the operating point through the path of E '→ G → E from the transient state, according to the present invention, the path of E' → J → K → E To recover the steady-state operating point.

At this time, in the control method for improving the transient performance of the HVDC system according to the embodiment of the present invention, in the inverter 102, by increasing the small angle command value by a predetermined small angle correction value in the controller 106, The voltage is controlled to be low.

4 is a block diagram of an inverter control apparatus to which a control method for improving transient performance of an HVDC system according to an embodiment of the present invention is applied.

Referring to FIG. 4, an inverter control apparatus to which a control method for improving transient performance of an HVDC system according to an embodiment of the present invention is applied includes an inverter of a high voltage direct current (HVDC) system A constant current control unit 410 for constantly controlling the current based on the current measurement value I m and the current instruction value I * of the control unit 400 based on the soho angle command value γ * new and the measured soho angle γ m The control unit 412 selects a control mode of the inverter 102 based on the output of the constant current control unit 410 and the output of the cancellation angle control unit 412, A control mode selection unit 408 for outputting the firing angle? I on the inverter 102 according to the mode and a control unit for adjusting the sole angle command value? * New applied to the subject cancellation control unit 412 414).

The constant current control unit 410 includes a first subtractor 404 for subtracting the current measurement value I m of the inverter 102 from the current instruction value I * And a constant current controller 400 for controlling the output current of the inverter 102 to be constant.

The testis firing angle controller 412 is Lo each instruction value of Lo each (γ m), the second subtracter 406 and the second subtracter 406 for subtracting the measurement of the inverter (102 of FIG. 1) in the (γ * new) And a cannon angle controller 402 for constantly controlling the angle of incidence of the inverter 102 based on the output of the cannon angle controller 402.

The control unit 414 acquires the firing angle α rec_c and the minimum firing angle α min of the rectifier 100 from the rectifier control unit 104 of FIG. 1 that controls the operation of the rectifier 100, the sum of the commutator 100 side firing angle (α rec_c) and the minimum firing angle (α min), the inverter 102 side of the constant current control overlapping each (μ inv_c) and the extinguishing angle (γ inv_c) output by (β inv_c ), and the inverter 102 side testis whistle (CEA: based on the sum (β inv_γ) of the constant extinction angle) overlapping each (μ inv_γ) and the extinguishing angle (γ inv_γ) output by the control, the testes firing angle control unit (? * New ) to be applied to the control unit 412 is adjusted.

The operation of the inverter control apparatus of the HVDC system according to an embodiment of the present invention will be described with reference to FIGS. 5 and 6 for a control method for improving the transient performance of the HVDC system according to an embodiment of the present invention I will explain.

In step S500 and step S600, the controller 414 receives the rectifier 100 side firing angle α rec_c and the minimum firing angle α min from the rectifier control unit 104 that controls the operation of the rectifier 100 of the HVDC system .

Rectifier 100 side firing angle in the (α rec_c) and the minimum firing angle (α min) is in Fig. 4 corresponding to the drive control section 106 shown in as a value measured by a side rectifier 100, the first Fig. The control unit 414 in the illustrated inverter control apparatus acquires from the rectifier control unit 104. [

Next, in steps S502 and S602, the control unit 414 determines whether the rectifier 100 operates in the constant current control mode.

The controller 414 determines that the rectifier 100 operates in the constant current control mode when the rectifier side firing angle α rec_c is larger than the rectifier side minimum firing angle α min as shown in step S602 .

Next, when the rectifier 100 operates in the constant current control mode, in steps S504 and S604, the control unit 414 determines whether the inverter 102 is operating in the constant current control mode.

As shown in step S604, the control unit 414 is inverter-side sum (β inv_c) the inverter 102 side testis firing angle of the overlapping each (μ inv_c) and the extinguishing angle (γ inv_c) output by the constant current control (CEA : it is determined if constant extinction angle) is greater than the sum (β inv_γ) of each redundant (μ inv_γ) and the extinguishing angle (γ inv_γ) output by the control, the inverter 102 is to be operating in the constant current control mode.

The overlap angle represents a period of time required for switching between the thyristor valves constituting the inverter (102).

The sum (β inv_c) according to the embodiment of the invention, a control mode selecting unit 408 shown in Figure 4 is a duplicate of each (μ inv_c) and the extinguishing angle (γ inv_c) outputted from the constant current controller 400 and testis duplicate output from the firing angle controller 402, select the maximum value of the sum (β inv_γ) of each (μ inv_γ) and the extinguishing angle (γ inv_γ) and determines the control mode.

That is, the control mode selection unit 408 is a duplicate that is output from the constant current controller 400 overlapping angle (μ inv_c) and extinguishing each of the sum (β inv_c) the testis firing angle controller 402 of (γ inv_c) outputted from the respective ( of μ inv_γ) and the extinguishing angle (sum (β inv_γ) is greater than, select the constant current control mode, and testis firing angle controller 402 overlapping angle (μ inv_γ) and the extinguishing angle (γ inv_γ) outputted from the γ inv_γ) the sum (β inv_γ) a constant current control redundant output at 400 for each (μ inv_c) and the extinguishing angle is greater than the sum (β inv_c) of (γ inv_c), by selecting the testis firing angle control mode, the inverter 102 of the And determines the operation control mode.

Therefore, the control unit 414 is the sum (β inv_c) and the inverter 102 side testis firing angle of the overlapping each (μ inv_c) and the extinguishing angle (γ inv_c) output by the inverter side of the constant current control (CEA: constant extinction angle) control by comparing the sum (β inv_γ) of each redundant (μ inv_γ) and the extinguishing angle (γ inv_γ) output by it it can be determined whether the inverter 102 is operating in a constant current control mode.

When both the rectifier 100 and the inverter 102 are operated in the constant current control mode, the control unit 414 controls the control unit 414 to control the opening angle command value gamma * new ) by a predetermined small angle correction value [gamma] add .

If it is determined in step S502 and step S602 that the rectifier 100 of the HVDC system does not operate in the constant current control mode or that the inverter 102 does not operate in the constant current control mode in steps S504 and S604 The control unit 414 holds the small angle command value gamma * new at the initial small angle command value gamma * ini .

As described above, according to the inverter control apparatus of the HVDC system and the control method for improving the transient performance of the HVDC system according to the embodiment of the present invention, in the transient state in which the failure occurs in the AC system of the rectifier 100, Instantaneous increase of the small angle command value gamma * new applied to the instantaneous whistle control unit 412 in the inverter control unit to control the DC voltage on the inverter 102 to be low to cause the inverter 102 to immediately exit the constant current control mode Let it operate in the canopy control mode, and then restore the normal operating point.

Therefore, the operation characteristics of the HVDC system to which the control method and the inverter control apparatus for improving the transient performance of the HVDC system according to the embodiment of the present invention are applied are as follows: E '→ J → K → E The output of the inverter 102 and the voltage variation of the AC system can be relatively reduced in the process of recovering the HVDC system after occurrence of a failure of the AC system on the side of the rectifier 100, It is possible to shorten the transient time, which is the arrival time of the vehicle.

simulation

Simulation condition

In order to verify the effect of the control method for improving the transient performance of the HVDC system and the inverter control device of the HVDC system according to the embodiment of the present invention, the HVDC model of FIG. 1 is used to compare before and after application of the present invention The performance of the present invention was confirmed.

In the simulation, it is assumed that a failure occurs in the AC system on the rectifier (100) side for 0.1 second in 2 seconds.

Simulation result

FIG. 7 is a graph showing the relationship between the sum of the overlap angle and the small angle (?) Of the inverter before the control method for improving transient performance of the HVDC system according to the embodiment of the present invention, the dotted angle of the rectifier side, And graphs showing respective command values.

The inverter 102 operates in the canonical whistle (CEA) control mode before a failure occurs in the AC system on the rectifier 100 side and after the occurrence of a failure of the AC system on the rectifier 100 in two seconds, (CE) control mode to the constant current (CC) control mode. This is because the inverter 102 side compensates for the DC current by the constant current (CC) control as the DC current decreases due to the decrease of the DC voltage on the rectifier 100 side. It can be confirmed that the DC voltage on the rectifier 100 is recovered due to the AC fault removal, the constant current CC control is performed on the rectifier side and the CEA control is performed on the inverter side after passing through the transient state.

FIG. 8 is a graph showing the relationship between the sum of the overlap angle and the small angle (?) On the inverter side after the control method for improving transient performance of the HVDC system according to the embodiment of the present invention, the dotted angle of the rectifier side, Fig.

Even when the present invention is applied, the operating characteristics in the steady state and during the failure are the same as those in the case where the present invention is not applied. However, in the period during which the inverter 102 operates in the constant current control mode during the recovery from the failure, the rectifier side dotted line angle? Rec_c is larger than the rectifier side minimum dotted line angle? Min , (? * New ) is increased.

Also, it can be seen that the time when the steady state operating angle is maintained after the switching of the control mode occurs is faster than when the present invention is applied, when the present invention is applied. At this time, it can be seen that when the present invention is applied, the switching point of the final control mode after the failure of the AC system on the rectifier side is removed is earlier than the case where the present invention is not applied. Also, it can be seen that the sum of the overlapping angles and the small angles (?) On the inverter side exhibits a more stable steady state recovery characteristic than the case where the present invention is not applied.

FIG. 9 is a graph showing a rectifier-side AC voltage and an inverter-side AC voltage before applying a control method for improving transient performance of an HVDC system according to an embodiment of the present invention. The AC voltage of the rectifier and the AC voltage of the inverter after applying the control method for improving the transient performance of the HVDC system.

As shown in FIG. 10, when the present invention is applied, it can be seen that the inverter-side AC voltage maintains a relatively stable state as compared with the case where the present invention is not applied.

FIG. 11 is a graph showing an output of an inverter after a failure occurs in a control system for improving the transient performance of an HVDC system according to an embodiment of the present invention, and in an AC system on a rectifier when not in use. In the case where the present invention is not applied, it is confirmed that it takes some time to maintain the steady state after the output fluctuation of the inverter.

However, when the present invention is applied, it is confirmed that the output fluctuation of the inverter 102 is reduced and the time for reaching the steady state is increased.

According to the control method for improving the transient performance of the HVDC system and the inverter control apparatus of the HVDC system according to the embodiment of the present invention, the HVDC system is relatively recovered after the failure of the AC system on the rectifier side, The voltage fluctuation of the AC system can be reduced and the transient time which is the arrival time to the steady state can be shortened.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It is clear that the present invention can be modified or improved.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

100: rectifier 102: inverter
104: rectifier control unit 106: inverter control unit
108: transmission line 110: rectifier side AC system
112: inverter side AC system 400: constant current controller
402: a subject's whistle controller 404: a first subtracter
406: second subtracter 408: control mode selector
410: constant current control unit 412:
414:

Claims (8)

A control method for improving transient performance of an HVDC system after a fault has been removed in the event of a fault in an AC system on a rectifier side of a high voltage direct current (HVDC) system,
(a) determining whether a rectifier of the HVDC system operates in a constant current control mode, in a control unit of an inverter control unit for controlling an operation of an inverter in the HVDC (High Voltage Direct Current) system;
(b) if the rectifier operates in the constant current control mode, determining in the control unit whether the inverter operates in a constant current control mode; And
(c) in order to allow the inverter to operate in the constant-current-speed control mode immediately after leaving the constant-current control mode when both the rectifier and the inverter operate in the constant current control mode, And a step of instantaneously increasing the small angle command value applied to the can hearer angle controller in the inverter controller by a predetermined small angle correction value to instantaneously lower the inverter side DC voltage to restore the inverter side DC current preferentially ,
The step (a)
(a-1) obtaining, at the control unit, a rectifier-side firing angle and a rectifier-side minimum firing angle from a rectifier control unit for controlling the operation of the rectifier; And
(a-2) The control unit compares the rectifier-side firing angle and the rectifier-side minimum firing angle, and when the rectifier-side firing angle is larger than the rectifier-side minimum firing angle, the rectifier operates in the constant current control mode Comprising:
In the step (b)
When the sum of the overlap angle and the soot angle output by the inverter constant current control is greater than the sum of the overlap angle and the soot angle output by the constant extinction angle control of the inverter, The method comprising the steps of: delete delete The method according to claim 1,
When it is determined in the step (a) that the rectifier of the HVDC system is not operated in the constant current control mode, or when it is determined in the step (b) that the inverter does not operate in the constant current control mode, Further comprising the step of: maintaining the setpoint at an initial summation angle command value. An inverter control apparatus for an HVDC system for improving transient performance of a HVDC system after a fault has occurred in the event of a fault in a rectifier AC system of a high voltage direct current (HVDC) system,
A constant current control unit for controlling a current of an inverter of the high voltage direct current (HVDC) system;
A cancellation angle control unit for controlling the soot angle of the inverter;
A control mode selecting unit for selecting a control mode of the inverter based on the output of the constant current control unit and the output of the instantaneous whistle control unit and outputting the firing angle of the inverter according to the selected control mode; And
And a control unit for adjusting an SOHO angle command value applied to the subject's whistle control unit,
Wherein,
(a) determining whether the rectifier of the HVDC system is operating in a constant current control mode,
(b) determining whether the inverter operates in a constant current control mode when the rectifier operates in a constant current control mode; And
(c) In case that both of the rectifier and the inverter are operated in the constant current control mode, in order to allow the inverter to immediately operate in the canopy control mode out of the constant current control mode and then to recover the normal operating point, Side DC voltage is instantaneously lowered by instantaneously increasing the small-angle command value applied to the inverter-side DC current by a predetermined small-angle correction value, thereby performing an operation of preferentially recovering the inverter-side DC current,
The operation (a)
(a-1) obtaining a rectifier side firing angle and a rectifier side minimum firing angle from a rectifier control unit for controlling the operation of the rectifier; And
(a-2) comparing the rectifier-side firing angle and the rectifier-side minimum firing angle to determine that the rectifier operates in the constant current control mode when the rectifier-side firing angle is larger than the rectification-side minimum firing angle / RTI >
If the sum of the overlap angle and the soot angle output by the inverter-side constant current control in the operation (b) is greater than the sum of the overlap angle and the so-called angle output by the constant extinction angle control of the inverter, And determines that the inverter operates in the constant current control mode. delete delete The method of claim 5,
When the rectifier of the HVDC system does not operate in the constant current control mode or the rectifier does not operate in the constant current control mode in the operation (a), the control unit sets the small angle angle command value as the initial small angle angle command value To the inverter control unit of the HVDC system.
KR1020150167414A 2015-11-27 2015-11-27 A control method to improve transient performance of hvdc system and an inverter control apparatus of hvdc system KR101767451B1 (en)

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인천대학교 졸업논문 "HVDC 제어..."

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