KR102326348B1 - System for Controlling Output Voltage of Multi Phase Controlled Rectifier - Google Patents

Abstract

The output voltage control system of a multi-phase controlled rectifier according to an aspect of the present invention, which can individually control the output voltage of each phase controller by calculating the firing angle for each phase controlled rectifier, uses 3 phase controlled rectifiers a power converter for converting the AC voltage of the phase into a DC voltage on the load side and outputting it; n firing angle controllers for calculating a firing angle for each phase control rectifier based on the output voltage command value of each phase control rectifier and the three-phase AC voltage input to the corresponding phase control rectifier; and n driving units for generating a switching signal for controlling the switching operation of the corresponding phase-controlled rectifier based on the firing angle calculated for each phase-controlled rectifier.

Description

System for Controlling Output Voltage of Multi Phase Controlled Rectifier

The present invention relates to a phase rectification controller, and more particularly, to an output voltage control of a multi-phase rectification controller.

A phase controlled rectifier is used as a power converter that converts alternating current to direct current. In particular, recently, a method of using two or more phase-controlled rectifiers to construct a large-capacity power supply of several MW or more has been proposed. For example, a large-capacity power supply including two or more phase-controlled rectifiers is proposed for large-capacity loads that require large currents or high voltages, such as DC motors or induction furnaces in steel mills, superconducting magnets for nuclear fusion, plasma generators, or heating devices. has been

1 shows an example of a power supply including two phase-controlled rectifiers. The first transformer 110a converts the three-phase grid voltage supplied from the grid 150 into a three-phase AC voltage according to the Y-delta connection (Y//Δ) and supplies it to the first phase-controlled rectifier 120a. The second transformer 110b converts the three-phase grid voltage supplied from the grid 150 into a three-phase AC voltage according to the Y-Y connection (Y//Y) and supplies it to the second phase-controlled rectifier 120b.

The first phase-controlled rectifier 120a converts the three-phase AC voltage supplied from the first transformer 110a into a DC voltage. The second phase controlled rectifier 120b converts the three-phase AC voltage supplied from the second transformer 110b into a DC voltage. The controller 130 controls the firing angles ( α) is determined, and the first and second driving units 140a and 140b are first and second for driving the first and second phase controlled rectifiers 120a and 120b based on the determined firing angle α. The switching signals S1 to S6 are generated.

In the case of the power supply device according to the prior art described above, as shown in FIGS. 2A and 2B , each of the phase control rectifiers 120a and 120b generates an output voltage (V _Δd , V _Yd ) having the same magnitude although a phase difference exists. As shown in FIG. 2c , the ideal output voltage V _O can be output from the load L side.

However, as shown in FIGS. 3A and 3B , the magnitude of the secondary-side AC voltage of the first transformer 110a is normal due to an error in the turns ratio of the wye-delta-connected (Y//Δ) first transformer 110a. _{Even when it is lowered by Δd AC} than the state _{, the output voltage V Δd} of the first phase controlled rectifier 120a _{and the output voltage V Yd} of the second phase controlled rectifier 120b are controlled by the same firing angle, _{The output voltage V Δd} of the first phase-controlled rectifier 120a is inevitably _{lowered by Δd DC,} so that an output voltage imbalance is inevitable at the output terminals of the first and second phase-controlled rectifiers 120a and 120b.

Due to this, power loss due to electrical stress of the phase-controlled rectifier outputting a relatively high voltage increases, and as shown in FIG. 3c , a ripple (ΔV _DC ) is generated in _{the output voltage (VO ) of the load side, resulting in harmonics} There is a problem in that the generation of noise increases and the control performance is deteriorated.

The present invention is to solve the above-described problem, and by calculating the firing angle for each phase-controlled rectifier, it is to provide an output voltage control system of a multi-phase controlled rectifier that can individually control the output voltage of each phase controller. characterized.

According to an aspect of the present invention for achieving the above object, the output voltage control system of a multi-phase controlled rectifier includes: a power conversion device for converting a three-phase AC voltage into a load-side DC voltage and outputting it by using n phase-controlled rectifiers; n firing angle controllers for calculating a firing angle for each phase control rectifier based on the output voltage command value of each phase control rectifier and the three-phase AC voltage input to the corresponding phase control rectifier; and n driving units for generating a switching signal for controlling the switching operation of the corresponding phase-controlled rectifier based on the firing angle calculated for each phase-controlled rectifier.

As described above, according to the present invention, since the firing angle of each phase-controlled rectifier is calculated by reflecting the phase of the three-phase AC voltage input to each phase-controlled rectifier, the size and phase deviation of the input-side AC power source are unbalanced. Also, there is an effect that the output voltage and power of each phase-controlled rectifier can be uniformly controlled.

In addition, according to the present invention, it is possible to equalize the output voltage and power of each phase-controlled rectifier through individual control of the output voltage of the phase-controlled rectifier. There is an effect that it is possible to reduce electrical stress and heat generation problems.

In addition, according to the present invention, since the output voltage and power of each phase-controlled rectifier are equalized, ripple and harmonic noise of the load-side output voltage can be reduced, thereby improving control performance and efficiency.

1 is a view showing an example of a power supply device including two phase-controlled rectifiers.
FIG. 2 is a graph showing voltage waveforms for each part of the power supply device shown in FIG. 1 under the equilibrium condition of the AC voltage on the output side of the transformer.
FIG. 3 is a graph showing voltage waveforms for each part of the power supply device shown in FIG. 1 under an unbalanced condition of AC voltage on the output side of the transformer.
4 is a block diagram showing the configuration of an output voltage control system of a multi-phase controlled rectifier according to an embodiment of the present invention.
5 is a block diagram showing the configuration of an output voltage control system of a multi-phase controlled rectifier including two phase controlled rectifiers.
FIG. 6 is a graph showing voltage waveforms in the output voltage control system of the multi-phase controlled rectifier shown in FIG. 5 .

Like reference numerals refer to substantially identical elements throughout. In the following description, detailed descriptions of configurations and functions known in the art and cases not related to the core configuration of the present invention may be omitted. The meaning of the terms described herein should be understood as follows.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention belongs It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims.

The shapes, sizes, proportions, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of the present invention are illustrative and the present invention is not limited to the illustrated matters. Like reference numerals refer to like elements throughout. In addition, in describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

When 'including', 'having', 'consisting', etc. mentioned in this specification are used, other parts may be added unless 'only' is used. When a component is expressed in the singular, the case in which the plural is included is included unless otherwise explicitly stated.

In interpreting the components, it is interpreted as including an error range even if there is no separate explicit description.

In the case of a description of the positional relationship, for example, when the positional relationship of two parts is described as 'on', 'on', 'on', 'beside', etc., 'right' Alternatively, one or more other parts may be positioned between the two parts unless 'directly' is used.

In the case of a description of a temporal relationship, for example, 'immediately' or 'directly' when a temporal relationship is described with 'after', 'following', 'after', 'before', etc. It may include cases that are not continuous unless this is used.

Although the first, second, etc. are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from another. Accordingly, the first component mentioned below may be the second component within the spirit of the present invention.

The term “at least one” should be understood to include all possible combinations from one or more related items. For example, the meaning of "at least one of the first, second, and third items" means 2 of the first, second, and third items as well as each of the first, second, or third items. It may mean a combination of all items that can be presented from more than one.

Each feature of the various embodiments of the present invention may be partially or wholly combined or combined with each other, technically various interlocking and driving are possible, and each of the embodiments may be implemented independently of each other or may be implemented together in a related relationship. may be

Hereinafter, an embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

4 is a diagram schematically showing the configuration of an output voltage control system of a multi-phase controlled rectifier according to an embodiment of the present invention.

The output voltage control system (400, hereinafter, referred to as a 'control system') of the multi-phase control rectifier according to an embodiment of the present invention converts the grid voltage supplied from the grid 410 into a DC voltage to the load 420. It includes a driving device 427 for driving the power converter 425 and the power converter 425 to supply. The power conversion device 425 includes a transforming unit 430 and a rectifying unit 440 , and the driving device 427 includes a driving unit 450 and a controller 460 .

The transformer unit 430 converts the grid voltage supplied from the grid 410 into a three-phase AC voltage according to the delta connection or the wye connection and supplies it to the rectification unit 440 . In an embodiment, the transformer unit 430 may include the same number of transformers as the number of phase control rectifiers included in the rectification unit 440 .

For example, when the rectifying unit 440 includes n phase-controlled rectifiers 440a to 440n (n is an integer greater than or equal to 2) as shown in FIG. 4 , the transformation unit 430 includes n transformers 430a to 430n. ) may be included. According to this embodiment, the n number of transformers 430a to 430n may be 1:1 connected to the n phase controlled rectifiers 440a to 440n.

The rectifying unit 440 converts the three-phase AC voltage supplied from the transformer unit 430 into a DC voltage and supplies it to the load 420 . To this end, the rectification unit 440 may include n phase-controlled rectifiers 440a to 440n.

In an embodiment, the n phase-controlled rectifiers 440a to 440n may be connected in series with each other. In this case, the sum of the DC voltages V1, V2, ?? , and Vn output from each of the n phase control rectifiers 440a to 440n becomes the output voltage Vo of the rectifying unit 440, so A high voltage can be output.

In another embodiment, the n phase-controlled rectifiers 440a to 440n may be connected in parallel to each other. In this case, since the sum of the currents output by each of the n phase control rectifiers 440a to 440n becomes the output current of the rectifying unit 440 , a large current can be output to the load 420 .

The driving unit 450 calculates the firing angle of each phase controlled rectifier 440a to 440n for each phase controlled rectifier 440a to 440n included in the rectification unit 440, respectively, and each phase controlled rectifier ( A switching signal for driving each of the phase control rectifiers 440a to 440n is generated based on the firing angle calculated for each 440a to 440n. To this end, the driving unit 450 includes n driving units 450a to 450n. According to this embodiment, the n driving units 450a to 450n are 1:1 connected to the n phase controlled rectifiers 440a to 440n.

The reason why the driving unit 450 according to the present invention calculates the firing angle for each phase control rectifier 440a to 440n by using the n driving units 450a to 450n is, the transformers included in the transformation unit 430 are When unbalance occurs in the three-phase AC voltage output from (430a to 430n) and the firing angles of each of the phase controlled rectifiers 440a to 440n are all calculated to be the same, the output voltage of each of the phase controlled rectifiers 440a to 440n is This is because the voltage imbalance occurs, and the generation of ripple components and harmonic noise in the DC voltage at the load end of the power converter 400 increases.

As described above, in the present invention, since the respective driving units 450a to 450n can calculate the firing angles of the phase-controlled rectifiers 440a to 440n connected to the corresponding driving units 450a to 450n, respectively, from the transformers 430a to 430n. Even when unbalance occurs in the output three-phase AC voltage, the unbalance of the three-phase AC voltage based on the firing angle calculated for each phase-controlled rectifier 440a-440n and the output voltage of each phase-controlled rectifier 440a-440n inequality can be compensated for.

To this end, each of the driving units 450a to 450n is a preset load-side output voltage command value and a shared voltage command value (Vn*) of the phase control rectifiers 440a to 440n determined based on the number of the phase control rectifiers 440a to 440n. and calculates an output voltage command value for each phase controlled rectifier 440a to 440n based on the DC voltages V1, V2, ??, and Vn output from each of the phase controlled rectifiers 440a to 440n. In addition, each of the driving units 450a to 450n uses the output voltage command value calculated for each phase control rectifier 440a to 440n and the line voltage of the three-phase AC voltage input to each phase control rectifier 440a to 440n. A firing angle is calculated for each control rectifier 440a to 440n.

Each of the driving units 450a to 450n generates a plurality of switching signals for switching the thyrist stack included in each phase controlled rectifier 440a to 440n based on the firing angle calculated for each phase controlled rectifier 440a to 440n. do. Each of the driving units 450a to 450 controls the operation of each of the phase control rectifiers 440a to 440n according to the generated switching signal, so that each of the phase control rectifiers 440a to 440n outputs a DC voltage corresponding to the output voltage command value. make it possible

The controller 460 calculates the shared voltage command value (Vn*) of each phase control rectifier (440a to 440n) based on the load-side output voltage command value (Vo*) input from the outside, and calculates the shared voltage command value (Vn*) is transmitted to each of the driving units 450a to 450n.

In one embodiment, the controller 450 sets the load-side output voltage command value Vo* of the phase control rectifiers 440a to 440n so that all of the phase control rectifiers 440a to 440n can output the same DC voltage. The divided power command value (Vn*) of the phase control rectifiers 440a to 440n may be calculated by dividing the result value by the number n.

In the above-described embodiment, the controller 460 receives the load-side output voltage command value Vo* from the outside, but in a modified embodiment, the controller 460 receives the load-side output current command value Io* from the outside. is input, and the load-side output voltage command value (Vo*) may be calculated from the actual load-side output current (Io) and the load-side output current command value (Io*) flowing to the load side through PI control.

Hereinafter, with reference to FIG. 5, the configuration of the control system according to the present invention will be described in more detail by taking the case where the power conversion device includes two phase-controlled rectifiers.

5 is a block diagram showing the configuration of an output voltage control system of a multi-phase controlled rectifier including two phase controlled rectifiers.

5, the control system 500 includes a first transformer 530a, a second transformer 530b, a first phase controlled rectifier 540a, a second phase controlled rectifier 540b, a first driving unit ( 550a), a second driving unit 550b, and a controller 560 .

The first transformer 530a converts the three-phase grid voltage supplied from the grid (not shown) into a three-phase first AC voltage according to the Y-delta connection (Y//Δ) to the first phase-controlled rectifier 540a. supply

The second transformer 530b converts the three-phase grid voltage supplied from the grid into a three-phase second AC voltage according to the Y/Y connection (Y//Y) and supplies it to the second phase-controlled rectifier 540b.

According to this embodiment, the second AC voltage supplied from the second transformer 530b to the second phase controlled rectifier 540b and the first AC voltage supplied from the first transformer 530a to the first phase controlled rectifier 540a A phase difference of 30 degrees exists between voltages.

The first phase-controlled rectifier 540a converts the first three-phase AC voltage supplied from the first transformer 530a into DC, thereby outputting _{a first DC voltage V Δo.} Specifically, the first phase controlled rectifier 540a converts the first AC voltage into the first DC voltage using the thyristor SCR. In one embodiment, the first phase controlled rectifier (540a) may include a thyristor stack consisting of a plurality of thyristors to implement a multi-pulse output. For example, the first phase controlled rectifier 540a may implement 6 pulse output by including 6 thyristors.

The turn-on time of the first phase controlled rectifier 540a according to the present invention is adjusted according to the size of the first firing angle calculated by the first driving unit 550a.

The second phase-controlled rectifier 540b converts the three-phase second AC voltage supplied from the second transformer 540b into DC to output _{a second DC voltage V Yo .} Specifically, the second phase control rectifier 540b converts the second AC voltage into the second DC voltage using the thyristor SCR. In one embodiment, the second phase controlled rectifier (540b) may include a thyristor stack consisting of a plurality of thyristors to implement a multi-pulse output. For example, the second phase control rectifier 540b may implement 6 pulse output by including 6 thyristors.

The turn-on time of the second phase controlled rectifier 540b according to the present invention is adjusted according to the magnitude of the second firing angle calculated by the second driving unit 550b.

A first drive section (550a) is to drive the first firing angle (α _△), the first firing angle first phase-controlled rectifier (540a) on the basis of the (α _△), and calculates a first phase-controlled rectifier (540a) to generate a first switching signal for To this end, the first driving unit 550a includes a first output voltage command value calculating unit 552a, a first firing angle controller 554a, and a first gating driver 556a as shown in FIG. 5 .

The first output voltage command value calculation unit 552a includes the shared voltage command value Vn* of the first phase control rectifier 540a calculated based on the load-side DC voltage command value Vo* and the first phase control rectifier 540a. An output voltage command value (V1*) of the first phase control rectifier is calculated based on the first DC voltage (V _{Δo), which is an actual output voltage.}

To this end, the first output voltage command value calculator 552a includes a first PI controller 552a_1 and a first adder 552a_2 .

A first PI controller (552a_1) is a sharing voltage instruction value of the first phase controller rectifier (540a) the actual output voltage of the first DC voltage (V _{△ o)} a first phase-controlled rectifier (540a) of the through PI control (Vn * ), calculates the first compensation voltage (V _Δo *) required to follow. A first PI controller (552a_1) transmits the first compensating voltage (V _{△ o} *) calculated by the first adder (552a_2).

5, the first though the output voltage command value calculating section (552a) described that calculates a first compensating voltage (V _{△ o} *) by using only the first PI controller (552a_1), the first output voltage command value calculating section (552a ) it will be also further include a limiter (limiter) in addition to a first PI controller (552a_1) to produce a first compensating voltage (V _{△ o} *).

A first adder (552a_2) is a first phase by adding the first PI controller (552_1), a first compensating voltage (V _{△ o} *) and sharing voltage command value (Vn *) of the first phase-controlled rectifier (540a) that is output from the A first output voltage command value V1* of the control rectifier 540a is calculated.

In this manner, the first output voltage command value computing unit the actual output voltage of the first DC voltage (V _{△ o)} a first phase-controlled rectifier (540a) of the first phase-controlled rectifier (540a) through (552a) according to the invention the calculated first compensation voltage (V _{△ o} *) is required so as to follow the ideal direct voltage of sharing voltage command value (Vn *) to be outputted, and reflecting the first compensating voltage (V _{△ o} *) first Since the output voltage command value (V1*) and the first firing angle (α _Δ ) are determined, even in an environment where an AC voltage imbalance occurs, the voltage between the first phase controlled rectifier 540a and the second phase controlled rectifier 540b and Power imbalance can be reduced.

The first firing angle controller 554a is the first output voltage command value V1* of the first phase control rectifier 540a and the first line voltage of the first AC voltage input to the first phase control rectifier 540a. 1 The first firing angle α _Δ of the phase controlled rectifier 540a is calculated. To this end, the first firing angle controller 554a includes a first PLL 554a_1 and a first firing angle calculating unit 554a_2 .

The first PLL (Phase Lock Loop, 554a_1) is the line voltage (V) of the first AC voltage input to the first phase control rectifier 554a._△ab, V_△bc, V_△ca) based on the first phase (θ) of the first AC voltage_△) is detected. The first PLL 554a_1 is the detected first phase θ_△) to the first firing angle calculation unit 554a_2.

The first firing angle calculator 554a_2 calculates the first phase θ _△ input from the first PLL 554a_1 and the first output voltage command value V1* input from the first adder 552a_2 at a predetermined firing angle. _{The first firing angle α Δ} of the first phase controlled rectifier 540a is calculated by input to the calculation algorithm. As an example, the first firing angle calculator 554a_2 may calculate the first firing angle α _Δ using Equation 1 below.

In Equation 1, αΔ represents the first firing angle, V1* represents the first output voltage command value, k ₁ represents the maximum output voltage that the first phase control rectifier 540a can output, and k ₁ may be defined as in Equation 2 below.

In Equation 2, V _LL1 represents an effective value of the first AC voltage input to the first phase-controlled rectifier 540a.

As described above, according to the present invention, the first firing angle calculator 554a_2 reflects _{the first phase θ Δ} of the first AC voltage output from the first transformer 530a to which the first phase control rectifier 540a is connected. the first point because it calculates the firing angle (α _△), the AC voltage is unbalanced, even if generated by a turns ratio error of the first transformer (530a) as a result can be this unbalance compensation on a first firing angle (α _△) The output voltage of the first phase-controlled rectifier 540a can be equally controlled with the output voltage of the second phase-controlled rectifier 540b.

First gating driver (556a) includes a first firing angle a plurality of first switching signal for controlling switching operation of the first phase-controlled rectifier (540a) on the basis of the (α _△) of the first phase-controlled rectifier (540a) ( S1 to S6) are created.

The first gating driver 556a applies a plurality of switching signals generated according to the first firing angle α _Δ to the gate terminals of the thyristors included in the first phase control rectifier 540a, respectively. By driving the 540a, the first phase controlled rectifier 540a can output a DC voltage corresponding to the first output voltage command value V1*.

The second driving unit 550b calculates the second firing angle of the second phase controlled rectifier 540b, and a second switching for driving the second phase controlled rectifier 540b based on the second firing _{angle α Y} generate a signal To this end, the second driving unit 550b includes a second output voltage command value calculating unit 552b, a second firing angle controller 554b, and a second gating driver 556b as shown in FIG. 5 .

The second output voltage command value calculation unit 552b includes the shared voltage command value Vn* of the second phase control rectifier 540b calculated on the basis of the load-side DC voltage command value Vo* and the second phase control rectifier 540b. The output voltage command value V2* of the second phase control rectifier 540b is calculated based on _{the second DC voltage V YO} which is the actual output voltage.

To this end, the second output voltage command value calculator 552b includes a second PI controller 552b_1 and a second adder 552b_2.

_{The second PI controller 552b_1 has the second DC voltage (V YO} ), which is the actual output voltage of the second phase controller rectifier 540b, through the PI control, the shared voltage command value (Vn*) of the second phase control rectifier 540b. Calculate the second compensation voltage (V _YO *) required to follow . The second PI controller 552b_1 transmits the calculated second compensation voltage V _YO * to the second adder 552b_2 .

In FIG. 5 , it has been described that the second output voltage command value calculation unit 552b calculates _{the second compensation voltage V YO} * using only the second PI controller 552b_1 , but the second output voltage command value calculation unit 552b may further include a limiter in addition to the second PI controller 552b_1 to calculate the second compensation voltage (V _{YO *).}

The second adder 552b_2 adds the second compensation voltage V _YO * output from the second PI controller 552b_1 and the shared voltage command value Vn* of the second phase control rectifier 540b to control the second phase A second output voltage command value V2* of the rectifier 540b is calculated.

_{As described above, according to the present invention, the second DC voltage V YO} which is the actual output voltage of the second phase controlled rectifier 540b through the second output voltage command value calculating unit 552b is the second phase controlled rectifier 540b _{Calculate the second compensation voltage (V YO} *) required to follow the shared voltage command value (Vn*), which is the ideal DC voltage to be output, and reflect the second compensation voltage (V _YO *) to the second output voltage command value Since (V2*) and the second firing angle α _Y are determined, the voltage and power imbalance between the first phase controlled rectifier 540a and the second phase controlled rectifier 540b even in an environment where an AC voltage imbalance occurs. can be made to decrease.

The second firing angle controller 554b is the second output voltage command value V2* of the second phase control rectifier 540b and the second phase control rectifier 540b based on the line voltage of the second AC voltage input to the second phase control rectifier 540b. 2 Calculate the second firing angle of the phase controlled rectifier 540b. To this end, the second firing angle controller 554b includes a second PLL 554b_1 and a second firing angle calculating unit 554b_2 .

The second PLL (554b_1) is the line voltage of the second AC voltage input to the second phase control rectifier (554b) (V _Yab , V _Ybc , Based on V _Yca ), the second phase θ _Y of the second AC voltage is detected. The second PLL 554b_1 transmits the detected second phase θ _Y to the second firing angle calculator 554b_2 .

The second firing angle calculator 554b_2 calculates the second phase θ _Y input from the second PLL 554b_1 and the second output voltage command value V2* input from the second adder 552b_2 at a predetermined firing angle. _{The second firing angle α Y} of the second phase controlled rectifier 540b is calculated by input to the calculation algorithm. As an example, the second firing angle calculator 554b_2 may calculate the second firing angle α _Y using Equation 3 below.

In Equation 3, α _Y represents the second firing angle, V2* represents the second output voltage command value, k ₂ represents the maximum output voltage that the second phase control rectifier 540b can output, and k ₂ can be defined as in Equation 4 below.

In Equation 4, V _LL2 represents an effective value of the second AC voltage input to the second phase controlled rectifier 540b.

As described above, according to the present invention, the second firing angle calculator 554b_2 reflects _{the second phase θ Y} of the second AC voltage output from the second transformer 530b to which the second phase control rectifier 540b is connected. and second firing angle due to calculate the (α _Y), the second AC voltage is unbalanced, even if generated by a turns ratio error of the transformer (530b) the second firing angle as a result there is such imbalance can be compensated by the (α _Y) It is possible to control the output voltage of the second phase controlled rectifier 540b to be equal to the output voltage of the first phase controlled rectifier 540a.

Second gating driver (556b) of the second firing angle (α _Y) a plurality of second switching signal for controlling switching operation of the second phase-controlled rectifier (540b) on the basis of the second phase-controlled rectifier (540b) ( S1 to S6) are created.

The second gating driver 556b applies _{a plurality of second switching signals generated according to the second firing angle α Y} to the gate terminals of the thyristors included in the second phase control rectifier 540b, respectively, to obtain a second phase By driving the control rectifier 540b, the second phase control rectifier 540b can output a DC voltage corresponding to the second output voltage command value V2*.

The controller 560 calculates the above-described shared voltage command value Vn*, and supplies the calculated shared voltage command value Vn* to the first and second output voltage command value calculation units 552a and 552b. To this end, the controller 560 may include a voltage control unit 562 , a current control unit 564 , and a switching unit 566 as shown in FIG. 5 .

First, when the voltage control unit 562 receives the load-side DC voltage command value Vo* from the outside, the input load-side DC voltage command value Vo* is divided by the number of the phase control rectifiers 540a and 540b to divide the shared voltage command value ( Vn*) is calculated. In FIG. 5, since two phase-controlled rectifiers 540a and 540b are included, the voltage controller 562 divides the load-side DC voltage command value Vo* by 2 to calculate the shared voltage command value Vn*. In an embodiment, the voltage controller 562 may be implemented as a voltage divider.

When the load-side output current command value (Io*) is input from the outside, the current control unit 564 receives the load-side output current command value (Io*) and the actual load-side output current (Io) based on the load-side output current command value (Vo*) through the PI control. ) is calculated. To this end, the current controller 564 may acquire the load-side output current Io by sensing the current flowing through the load-side L. The current control unit 564 calculates the shared voltage command value Vn* by dividing the calculated load-side DC voltage command value Vo* by the number of phase control rectifiers 540a and 540b. To this end, the current controller 564 may be implemented as a PI controller 564a and a voltage divider 564b, as shown in FIG. 5 . Although not shown in Figure 5, the current control unit 564 may further include a limiter to calculate the load-side DC voltage command value (Vo*).

The switching unit 566 selects any one of the voltage control unit 562 and the current control unit 564 according to a value input from the outside. Specifically, the switching unit 566 selects the voltage control unit 562 when the output pressure command value Vo* is input from the outside, and selects the current control unit 564 when the load-side output current command value Io* is input from the outside. can

As described above, according to the present invention, the first and second driving units 550a and 550b calculate the first and second firing angles of the first and second phase controlled rectifiers 540a and 540b, respectively. Even when unbalance occurs in the three-phase AC voltage output from the second transformers 530a and 543b, the unbalance of the three-phase AC voltage and the output voltage unbalance of the first and second phase control rectifiers 540a and 540b can be compensated. Therefore, it is possible to remove ripple and harmonic noise components from the load-side output voltage.

6 shows a voltage waveform in the control system according to the present invention. _{As shown in FIG. 6A, even if the magnitude of the line voltage is lowered by Δd AC} compared to the normal state according to the error in the turns ratio of the first transformer 540a connected with the Y-delta (Y-Δ) connection, the first phase controlled rectifier The 540a is controlled by the first firing angle α _Δ calculated for the first phase controlled rectifier 540a. Accordingly, as compared with the voltage waveform shown in FIG. 3b , _{it can be seen that the voltage as much as Δd DC} generated in the output voltage of the first phase controlled rectifier 540a is compensated, and thereby the first phase controlled rectifier 540a It can be seen that the voltage peak value of the load-side output voltage Vo, which is defined as the sum of the output voltage of , and the output voltage of the second phase-controlled rectifier 540b, is also maintained constant.

Those skilled in the art to which the present invention pertains will understand that the above-described present invention may be embodied in other specific forms without changing the technical spirit or essential characteristics thereof.

Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the following claims rather than the above detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention. do.

400: control system 410: system
420: load 430: transformer unit
440: rectification unit 450: drive unit
460: controller

Claims (15)

a power converter for converting a 3-phase AC voltage into a load-side DC voltage and outputting it using n phase-controlled rectifiers;
n firing angle controllers for calculating a firing angle for each phase control rectifier based on the output voltage command value of each phase control rectifier and the three-phase AC voltage input to the corresponding phase control rectifier;
n gating drivers for generating a switching signal for controlling a switching operation of the corresponding phase-controlled rectifier based on the firing angle calculated for each of the phase-controlled rectifiers; and
A controller for calculating the shared voltage command value of each phase control rectifier based on at least one of a load-side DC voltage command value of the power conversion device and an output current command value of the power conversion device;
The controller is
a voltage control unit dividing the load-side DC voltage command value by the number of the phase control rectifiers to calculate a shared voltage command value of each phase control rectifier;
The load-side DC voltage command value is calculated based on the output current command value and the actual output current of the power conversion device through PI control, and the calculated load-side DC voltage command value is divided by the number of the phase control rectifiers to control each phase a current control unit for calculating a shared voltage command value of the rectifier; and
and a switching unit that selects the current control unit when the output current command value is input from the outside, and selects the voltage control unit when the load-side DC voltage command value is input from the outside. According to claim 1,
The n firing angle controllers are
The first output voltage command value calculated based on the first output voltage output from the first phase control rectifier and the first firing angle for calculating the first firing angle based on the first AC voltage of the three phases input to the first phase control rectifier firing angle controller; and
Based on a second output voltage command value output from the second phase-controlled rectifier and calculated based on a second output voltage of a voltage level different from the first output voltage, and a three-phase second AC voltage input to the second phase-controlled rectifier a second firing angle controller for calculating a second firing angle with
The n gating drivers are
a first gating driver for generating a first switching signal for controlling a switching operation of the first phase controlled rectifier based on the first firing angle; and
and a first gating driver generating a second switching signal for controlling a switching operation of the second phase-controlled rectifier based on the second firing angle. According to claim 1,
The n number of firing angle controllers include three or more firing angle controllers, and the three or more firing angle controllers calculate a firing angle having a different value for each phase control rectifier corresponding to the corresponding firing angle controller,
The n gating drivers include three or more gating drivers, and the three or more gating drivers generate a switching signal for controlling the switching operation of the phase-controlled rectifier to which the corresponding gating driver is connected based on the different firing angles, respectively. The output voltage control system of the multi-phase control rectifier, characterized in that. According to claim 1,
Based on the shared voltage command value of each phase-controlled rectifier calculated based on the load-side DC voltage command value of the power conversion device and the actual output voltage of each phase-controlled rectifier, the output voltage command value of each phase control rectifier is calculated based on n The output voltage control system of the multi-phase control rectifier, characterized in that it further comprises an output voltage command value calculation unit. 5. The method of claim 4,
The output voltage command value calculation unit,
a PI controller for calculating a compensation voltage necessary for the actual output voltage of each of the phase-controlled rectifiers to follow the shared voltage command value of each of the phase-controlled rectifiers for each of the phase-controlled rectifiers; and
and an adder for calculating the output voltage command value of each phase control rectifier by adding the compensation voltage of each phase control rectifier and the shared voltage command value of each phase control rectifier; . delete delete According to claim 1,
The firing angle controller is
A PLL (Phase Lock Loop) for detecting the phase of the three-phase AC voltage based on the line voltage of the three-phase AC voltage input to each of the phase-controlled rectifiers: And
A firing angle calculation unit for calculating the firing angle of each phase control rectifier by inputting the phase of the three-phase AC voltage of each phase control rectifier and the output voltage command value of each phase control rectifier to a predetermined firing angle calculation algorithm The output voltage control system of a multi-phase control rectifier, characterized in that it. According to claim 1,
The power converter is
a first transformer for converting the three-phase grid voltage into a three-phase first AC voltage according to the wye-delta connection;
a first phase controlled rectifier for converting the first AC voltage of the three phases into DC and outputting a first DC voltage;
a second transformer for converting the three-phase grid voltage into a three-phase second AC voltage according to the Y-Wye connection; and
and a second phase controlled rectifier that converts the three-phase second AC voltage into DC and outputs a second DC voltage. 10. The method of claim 9,
The first and second phase controlled rectifiers are connected in series to each other, and the sum of the first DC voltage and the second DC voltage is output as the load-side DC voltage. system. 10. The method of claim 9,
The firing angle controller is
A first PLL for detecting a first phase of the first AC voltage based on the line voltage of the first AC voltage; And
Comprising a first firing angle calculator for calculating the first firing angle of the first phase controlled rectifier by inputting the first phase and the first output voltage command value of the first phase controlled rectifier to a predetermined firing angle calculation algorithm The output voltage control system of a multi-phase control rectifier, characterized in that it. 12. The method of claim 11,
a controller for calculating a shared voltage command value of the first and second phase control rectifiers based on at least one of a load-side DC voltage command value of the power conversion device and an output current command value of the power conversion device;
a first PI controller for calculating a first compensation voltage required for the first output voltage of the first phase-controlled rectifier to follow the shared voltage command value; and
and a first adder for calculating the first output voltage command value by adding the first compensation voltage and the shared voltage command value, and inputting the first output voltage command value to the first firing angle calculation unit. Output voltage control system of multi-phase control rectifier. 10. The method of claim 9,
The firing angle controller is
a second PLL for detecting a second phase of the second AC voltage based on the line voltage of the second AC voltage; And
Comprising a second firing angle calculator for calculating the second firing angle of the second phase controlled rectifier by inputting the second phase and the second output voltage command values of the second phase controlled rectifier to a predetermined firing angle calculation algorithm The output voltage control system of a multi-phase control rectifier, characterized in that it. 14. The method of claim 13,
a controller for calculating a shared voltage command value of the first and second phase control rectifiers based on at least one of a load-side DC voltage command value of the power conversion device and an output current command value of the power conversion device;
a second PI controller for calculating a second compensation voltage required for the second output voltage of the second phase-controlled rectifier to follow the shared voltage command value; and
and a second adder for calculating the second output voltage command value by adding the second compensation voltage and the shared voltage command value, and inputting the second output voltage command value to the second firing angle calculator. Output voltage control system of multi-phase control rectifier. 10. The method of claim 9,
The gating driver is
a first gating driver for generating a plurality of first switching signals for controlling a switching operation of a first thyrist stack included in the first phase controlled rectifier based on a first firing angle of the first phase controlled rectifier; and
and a second gating driver for generating a plurality of second switching signals for controlling a switching operation of a second thyrist stack included in the second phase controlled rectifier based on a second firing angle of the second phase controlled rectifier The output voltage control system of the multi-phase control rectifier, characterized in that.

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