KR101561386B1 - Hvdc cotroller for controlling firing pulse interpolation of hvdc system - Google Patents

Abstract

Provided is an HVDC controller for controlling the firing pulse interpolation of an HVDC system, which includes a firing pulse interpolation part which outputs a firing pulse, and performs firing pulse interpolation calculation to output a firing pulse interpolation time; and a count delay and input/output processing part which performs count delay by corresponding to a firing pulse interpolation time for the firing pulse received from the firing pulse interpolation part, and performs an input/output process for outputting a firing pulse to a thyristor.

Description

HVDC CONTROLLING FIRING PULSE INTERPOLATION OF HVDC SYSTEM BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

More particularly, the present invention relates to a HVDC control apparatus for predicting control pulse delay of an HVDC system, and more particularly, to a HVDC control apparatus for performing a predictive control so as to minimize a delay pulse, To an HVDC control apparatus for an assist pulse prediction control of an HVDC system.

There are two ways of linking the power system: one is to connect AC power system as it is, and the other is to convert AC power to DC power through power converter to connect system.

In recent years, there has been a growing interest in a method of converting AC power into DC power and linking the power system rather than directly linking the AC power system.

In Korea, a high voltage direct current (HVDC) system using a power converter is installed between Jeju and Haenam to link the power system of Jeju and Haenam.

High voltage direct current transmission (HVDC) system is a type of electric power transmission system that converts high-voltage alternating-current power generated by a power plant into direct-current power and transmits it again, and then re-converts it into alternating- .

There are several advantages of the DC transmission system.

First, the DC voltage is only about 70% of the maximum value of the AC voltage. Therefore, the UHV DC transmission system is easy to insulate and low in voltage, so the number of insulators installed in each device and the height of the pylon .

The most important advantage of the ultra high voltage DC transmission system is that the power transmission efficiency can be increased because the DC transmission system has less transmission loss than the AC system when the same power is transmitted. In an ultra high voltage direct current transmission system, the direct current can carry more than twice as much current as the alternating current.

An ultra high voltage DC transmission system can reduce the use of electric wires and reduce the area of the transmission line, which is effective and can improve the stability of the system by connecting between two AC systems of different voltage and frequency.

The high-voltage DC transmission system has no restriction on the transmission distance, and the DC transmission system is also inexpensive to construct the land power transmission over 450 Km or the power transmission through the sea floor over 40 Km.

Therefore, HVDC transmission system is used for power system connection of renewable energy, especially power transmission of large scale offshore wind farm.

In other countries, such as China and India, the distance between the power plant and the electric user is more than 1000 Km, so the distribution of the ultra high voltage DC transmission system is rapidly expanding.

This HVDC system is classified into a current type HVDC system using a thyristor valve and a voltage type HVDC system using an IGBT element.

In the HVDC system, the firing pulse is the most important factor controlling the operation of the thyristor to convert DC to AC.

The ignition pulse generated from the HVDC controller is transferred to the thyristor by optical or electric signal, and the thyristor operates according to this signal. However, in a digital HVDC control system, control operations are performed discreetly with a time interval of several tens to several hundreds of usec. Therefore, until the algorithmically generated increment pulse arrives at the thyristor, A delay of several tens to several hundreds [usec] is inevitable. The error due to the delayed pulse delay is 1 [deg] or more (46.3 [usec] is 1 [deg]). In the actual operation state of the HVDC, it is considered that the arc pulse is operated between 4 and 5 degrees Can be a very large error that can affect the performance of HVDC.

1 is a view for explaining a conventional HVDC control apparatus.

Referring to FIG. 1, a conventional HVDC system 1 includes an HVDC controller 10 and a thyristor 20.

The HVDC control apparatus 10 includes an increment pulse operation unit 11 for performing an increment pulse operation and an operation correction and input / output processing unit 12 for performing operation correction and input / output processing, .

The conventional HVDC control apparatus 10 is applied to a method of reducing the overall calculation pulse delay time by decreasing the control calculation time using the pulse pulse arithmetic operation unit 11 implemented through a high-speed DSP (Digital Signal Processor) A high-speed DSP that implements the pulse operation unit 11 is expensive and difficult to be applied to an industrial application.

The increment pulse operation section 11 includes a control algorithm for generating an increment pulse and performs an operation at a control operation cycle of several tens of usec according to the DSP performance of the increment pulse operation section 11. [

The computation correction and input / output processing unit 12 can be implemented in an FPGA and performs a processing speed within 1 usec according to the performance of the FPGA of the computation correction and input / output processing unit 12. [

And transmits the counting pulse generated by the counting pulse arithmetic operation unit 11 to the thyristor 20 through digital output.

At this time, the arithmetic correction and input / output processing unit 12 may apply additional logic to minimize the delay of the incremental pulse by the discrete operation.

Recently, high-speed DSPs have been widely developed, but HVDC systems tend to use DSPs whose stability has been sufficiently verified. Therefore, the HVDC system has a burden to use the latest high-speed DSP, so the speed of the DSP may be restricted. This is a factor directly affecting the pulse delay.

Also, in the conventional case, after the arc pulse generating operation is completed in the arc pulse operating section 11, it is transmitted to the thyristor 20, and therefore there is a structural delay. It is an important problem that it is possible to reduce this delay, and it is impossible to solve this problem by a calculation delay of the pulse pulse arithmetic operation unit 11 or a signal transmission delay.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an HVDC control apparatus for an assist pulse predictive control of an HVDC system that performs predictive control so as to minimize a delay pulse that can be generated when a digital type control is performed in an HVDC system .

According to an aspect of the present invention, there is provided an apparatus for generating a pulse signal, the pulse signal processor comprising: a pulse count predicting unit for outputting a pulse count and performing a pulse count prediction calculation to output a count pulse count; And a count delay and an input output processor for performing a count delay in accordance with the advance pulse predicted time with respect to the advance pulse received from the advance pulse predictor and outputting a count pulse to the thyristor, There is provided an HVDC control device for controlling pulse advance prediction of a system.

The guard pulse predictor may be implemented as a general-purpose DSP.

The general-purpose DSP can have an operation speed within 200 usec.

Wherein the control pulse predicting unit linearizes the first signal and the second signal for predicting the increment pulse during the control operation period to calculate the advance pulse prediction position where the first signal and the second signal meet before the next operation, It is possible to determine the time to the advance pulse prediction position as the advance pulse prediction time.

The count delay and the input / output processor may be implemented in an FPGA.

The FPGA may have a processing speed of less than 1 microseconds.

According to the present invention, by performing predictive control of the ignition pulse when performing digital control in the HVDC system, it is possible to minimize the ignition pulse delay using the general-purpose DSP and the FPGA.

1 is a view for explaining a conventional HVDC control apparatus.
2 is a view for explaining a HVDC control apparatus according to an embodiment of the present invention.
FIG. 3 is a graph for explaining the pulse pulse predicting control of the HVDC controller according to the embodiment of the present invention.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. It should be understood, however, that there is no intention to limit the scope of the present invention to the embodiment shown, and other embodiments which are degenerative by adding, changing or deleting other elements or other embodiments falling within the spirit of the present invention Can be proposed.

Although the term used in the present invention is a general term that is widely used at present, there are some terms selected arbitrarily by the applicant in a specific case. In this case, since the meaning is described in detail in the description of the corresponding invention, It is to be understood that the present invention should be grasped as a meaning of a non-term.

That is, in the following description, the word 'comprising' does not exclude the presence of other elements or steps than those listed.

2 is a view for explaining a HVDC control apparatus according to an embodiment of the present invention.

Referring to FIG. 2, the HVDC system 2 according to an embodiment of the present invention includes an HVDC controller 100 and a thyristor 200.

The HVDC controller 100 includes a counting delay unit 110 for counting the number of pulses in accordance with a predicted time of the counting pulse predictor 110, And an input output processing unit 120, and outputs an address pulse to the thyristor 200.

In detail, the agile pulse predicting unit 110 can predict one control operation cycle at the time of calculating the increment pulse. More specifically, advance pulse prediction is performed by the advance pulse predicting unit 110 before the general-purpose DSP (control unit) performs an arithmetic operation as an arithmetic unit, so that before the general-purpose DSP (control unit) The control operation cycle and the position of the ignition pulse can be predicted and reflected in the operation. However, for the sake of convenience of explanation, FIG. 2 also shows the increment pulse prediction unit of the present invention together with a general-purpose DSP.

The count delay and input / output processing unit 120 may be implemented in an FPGA and perform a processing speed within 1 usec according to the count delay and the performance of the FPGA of the input / output processing unit 120.

The count delay and input / output processing unit 120 performs a role of transmitting the increment pulse generated by the increment pulse predicting unit 110 to the thyristor 200 through digital output.

The count delay and the input / output processing unit 120 delay the time until the time predicted by the advance pulse predicting unit 110 (count delay), and then transmit the signal to the thyristor 200.

FIG. 3 is a graph for explaining the pulse pulse predicting control of the HVDC controller according to the embodiment of the present invention.

Referring to FIG. 3, the pulse pulse predicting unit 110 linearizes the signal 1 and the signal 2 during a control operation cycle of 200 usec, and predicts a point before the next operation. That is, the guard pulse predicting unit 110 predicts generation of the guard pulse before one control operation cycle through interpolation. In order to perform a control operation by a general-purpose DSP (control unit) having an operation speed within 200 usec, the advance pulse predicted position predicted by the advance pulse predictor 110 is reflected in the operation.

The time from the current computation position to the increment pulse prediction position is the increment pulse prediction time, which is the count delay and the count delay time in the input / output processing unit 120. [ The guard pulse predictor 110 transfers the guard pulse predicted time to the count delay and the input / output processor 120.

The count delay and input / output processing unit 120 receives the command pulse signal and the command pulse predicted time from the command pulse predicting unit 110, performs a count delay corresponding to the pulse predicted time, and outputs a command pulse to the thyristor 200 .

Since the time period of 200 usec, which is the control operation cycle of the increment pulse predicting unit 110, takes a very short time in consideration of the characteristics of the signals 1 and 2, a large error does not occur in the linearization. In addition, when a high-speed DSP is used in implementing the guard pulse predicting unit 110, the linearization time is reduced and the error can be further reduced.

While the invention has been shown and described with reference to certain preferred embodiments thereof, 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 invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims and the claims.

Claims (4)

A control device for generating and outputting an ignition pulse for controlling the operation of a thyristor for performing a DC to AC conversion in an HVDC (High Voltage Direct Current) system,
A control operation is periodically performed to calculate the time of the ignition pulse to be transmitted to the thyristor,
Means for predicting the advance pulse before the next cycle of the control operation,
An advance pulse predictor for predicting the generation of the advance pulse and outputting the predicted advance pulse predicted position and the advance pulse predicted time;
And a count delay and an input output processing unit for performing a count delay in accordance with the count value of the control pulse received from the pulse count predicting unit and outputting the count pulse to the thyristor, HVDC controller for predictive control. The method according to claim 1,
Wherein the control pulse predicting unit linearizes the first signal and the second signal during the current control operation period to predict the advance pulse and calculates the advance pulse predictive position where the first signal and the second signal meet before the next operation, A HVDC control apparatus for an ignition pulse predictive control of an HVDC system for determining a time from a current computation position to a predicted pulse position as a predicted pulse prediction time. The method according to claim 1,
Wherein the control pulse predicting unit is a HVDC controller for the pulse pulse predictive control of an HVDC system having an operating speed within 200 usec. The method according to claim 1,
Wherein the count delay and the input output processing unit have a processing speed of 1 microsecond or less.

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