WO2019176008A1 - Rectifier - Google Patents

Abstract

An arm (11) of a thyristor rectifier includes: first and second conductors (21, 22); and first to eighth thyristors (Q1-Q8). The first to eighth thyristors (Q1-Q8) are sequentially arranged in the same direction as that for the first and second conductors (21, 22), have respective anode electrodes (31) connected to the first conductor (21), and have respective cathode electrodes (32) connected to the second conductor (22). A slit (21a) for increasing the impedance of a current path (P1) of the first thyristor (Q1) is formed in the first conductor (21) so as to reduce the variation in currents (Iq1-Iq8) of the first to eighth thyristors (Q1-Q8).

Description

rectifier

The present invention relates to a rectifier, and more particularly, to a rectifier including a plurality of rectifier elements connected in parallel.

For example, Japanese Patent Application Laid-Open No. 2008-92799 (Patent Document 1) discloses a plurality of thyristor rectifiers connected in parallel, a gate drive circuit that outputs a plurality of gate pulse signals for firing the plurality of thyristor rectifiers, and An excitation device is disclosed that includes a phase adjustment switch for reducing variation in current flowing through a plurality of thyristor rectifiers by manually adjusting the phase of each of a plurality of gate pulse signals.

JP 2008-92799 A

However, in Patent Document 1, it is necessary to provide a phase adjustment switch and manually adjust the phase of each of the plurality of gate pulse signals.

Therefore, a main object of the present invention is to provide a rectifier capable of reducing the cost of the apparatus.

The rectifier according to the present invention is arranged in the same direction as the first and second conductors extending in the same direction and the first and second conductors, and is connected in parallel between the first and second conductors. The first to Nth rectifying elements are provided. N is an integer of 2 or more. The first conductor is formed with a slit that increases at least the impedance of the current path of the first rectifying element.

In the rectifier according to the present invention, the first to Nth rectifier elements are sequentially arranged in the same direction as the first and second conductors and connected in parallel between the first and second conductors, and at least the first rectifier element A slit for increasing the impedance of the current path is formed in the first conductor. Accordingly, it is possible to reduce the variation in impedance of the current paths of the first to Nth rectifying elements, and to reduce the variation in current of the first to Nth rectifying elements. Therefore, since the necessity for manually adjusting the phase of each of the plurality of gate pulse signals is reduced, the cost of the apparatus can be reduced.

It is a block diagram which shows the structure of the power converter device by one Embodiment of this invention. It is a circuit diagram which shows the structure of the arm shown in FIG. It is a front view which shows the structure of the arm shown in FIG. It is a figure which shows the dispersion | variation in the electric current which flows into the several thyristor shown in FIG. It is a front view which shows the structure of the arm shown in FIG. It is a front view which shows the structure of the arm used as the comparative example of this Embodiment. It is a figure which shows the dispersion | variation in the electric current which flows into the some thyristor shown in FIG. It is a figure which shows the electric current path | route of the thyristor of both ends shown in FIG. It is a figure which shows the electric current path | route of the thyristor of both ends shown in FIG.

FIG. 1 is a block diagram showing a configuration of a power conversion apparatus according to an embodiment of the present invention. In FIG. 1, the power conversion device includes a thyristor rectifier 1 and a control device 2. The thyristor rectifier 1 is controlled by the control device 2, converts the three-phase AC voltages Va, Vb, and Vc supplied from the AC power supply 3 into three-phase full-wave rectification into a DC voltage VDC and supplies it to the load 4. The load 4 is driven by DC power supplied from the thyristor rectifier 1. The control device 2 operates in synchronization with the three-phase AC voltages Va, Vb, and Vc from the AC power supply 3, and controls the thyristor rectifier 1 so that the DC output voltage VDC becomes the target DC voltage VDCT.

More specifically, the thyristor rectifier 1 includes AC input terminals T1 to T3, DC output terminals T4 and T5, and arms 11 to 16. The AC input terminals T1 to T3 receive three-phase AC voltages Va, Vb, and Vc supplied from the AC power source 3, respectively. The DC output terminals T4 and T5 are connected to the positive electrode 4a and the negative electrode 4b of the load 4, respectively.

As shown in FIG. 2, the arm 11 includes an anode terminal 11a, a cathode terminal 11b, and N thyristors Q1 to QN (first to Nth rectifying elements). N is an integer of 2 or more. The anodes of the thyristors Q1 to QN are all connected to the anode terminal 11a, and the cathodes of the thyristors Q1 to QN are all connected to the cathode terminal 11b. The gates of thyristors Q1 to QN receive gate pulse signal G1 from control device 2.

The thyristors Q1 to QN are turned on in response to the gate pulse signal G1 when a forward bias voltage is applied between the anode terminal 11a and the cathode terminal 11b. The thyristors Q1 to QN are turned off when a reverse bias voltage is applied between the anode terminal 11a and the cathode terminal 11b.

The number N of thyristors is set according to the current Ia flowing through the arm A1. The number N of thyristors Q is set so that Ic × N> Ia, where Ia is the current flowing through the arm A1 and Ic is the rated current of one thyristor Q.

Each of the other arms 12 to 16 has the same configuration as the arm 11. Each of the arms 12 to 16 includes N thyristors Q1 to QN connected in parallel. The gates of thyristors Q1 to QN of arms 12 to 16 receive gate pulse signals G2 to G6 from control device 2, respectively.

Returning to FIG. 1, the anode terminals 11a to 13a of the arms 11 to 13 are connected to AC input terminals T1 to T3, respectively, and the cathode terminals 11b to 13b of the arms 11 to 13 are all connected to the positive DC output terminal T4. The The anode terminals 14a to 16a of the arms 14 to 16 are all connected to the negative DC output terminal T5, and the cathode terminals 14b to 16b of the arms 14 to 16 are connected to the AC input terminals T1 to T3, respectively.

The control device 2 operates in synchronization with the three-phase AC voltages Va, Vb, and Vc from the AC power supply 3, and generates gate pulse signals G1 to G6 so that the DC output voltage VDC becomes the target DC voltage VDCT. Give to arms 11-16.

Note that the phases of the AC voltages Va to Vc are shifted by 2π / 3. The gate pulse signal G1 is output after the elapse of the control angle α after the rising AC voltage Va coincides with the falling AC voltage Vc. The gate pulse signal G2 is output after the control angle α has elapsed since the rising AC voltage Vb coincides with the falling AC voltage Va. The gate pulse signal G3 is output after the control angle α has elapsed since the rising AC voltage Vc coincides with the falling AC voltage Vb.

The gate pulse signal G4 is output after the control angle α has elapsed after the falling AC voltage Va coincides with the rising AC voltage Vc. The gate pulse signal G5 is output after the control angle α has elapsed since the falling AC voltage Vb coincides with the rising AC voltage Va. The gate pulse signal G6 is output after the control angle α has elapsed after the falling AC voltage Vc coincides with the rising AC voltage Vb.

Therefore, the arms 11 to 13 are sequentially turned on by 2π / 3 (rad), and the arms 14 to 16 are sequentially turned on by 2π / 3 (rad) with a delay of π (rad) from the arms 11 to 13. The timing at which the arms 11 to 16 are turned on, that is, the timing at which the gate pulse signals G1 to G6 are output is adjusted by the control angle α. The control angle α is adjusted by the control device 2 so that the DC output voltage VDC of the thyristor rectifier 1 becomes the target DC voltage VDCT.

As described above, each of the arms 11 to 16 includes N thyristors Q1 to QN connected in parallel. When the current Ia flowing through each of the arms 11 to 16 is equally divided into N thyristors Q1 to QN, the current Iq flowing through each thyristor Q is Ia / N. In this case, a low-cost thyristor having a rated current Ic slightly larger than Ia / N can be used.

However, when the arm current Ia is not evenly divided into the N thyristors Q1 to QN and the variation in the current Iq flowing through the thyristors Q1 to QN is large, the maximum value IH of the current Iq is larger than the average value Ia / N. It gets quite big. In this case, it is necessary to use a high-priced thyristor Q whose rated current Ic is larger than the maximum value IH, which increases the cost. In the embodiment, this problem is solved.

FIG. 3 is a front view showing the configuration of the arm 11. FIG. 3 shows a case where N = 8. The arm 11 includes thyristors Q1 to Q8 and conductors 21 to 23. The conductor 21 (first conductor) is formed of a strip-shaped (or rectangular) metal plate (for example, a copper plate), and extends in the vertical direction in the figure. The conductor 22 (second conductor) is formed of a strip-shaped (or rectangular) metal plate (for example, a copper plate), and extends in the vertical direction in the figure. The upper end portion of the conductor 22 constitutes the cathode terminal 11b. The conductor 21 and the conductor 22 are arranged in parallel at a predetermined interval. The conductor 21 is disposed in the width direction of the conductor 22.

The conductor 23 is formed of a strip-shaped (or rectangular) metal plate (for example, a copper plate), and extends in the left-right direction in the drawing. The left end portion of the conductor 23 is connected to the lower right end portion of the conductor 21. The right end portion of the conductor 23 constitutes the anode terminal 11a.

A slit 21a having a predetermined dimension (predetermined width and predetermined length) is formed from the center of the short side of the upper end of the conductor 21 downward. The upper end portion of the conductor 21 is divided into a first portion 21b on the opposite side of the conductor 22 and a second portion 21c on the conductor 22 side by a slit 21a. Since the slit 21 a needs to be provided and connected to the conductor 23, the width of the conductor 21 is larger than the width of the conductor 22.

The main bodies of the thyristors Q1 to Q8 are arranged between the conductor 21 and the conductor 22, and are arranged in order from the upper side to the lower side in the figure. The anode electrode 31 (first electrode) of each of the thyristors Q1 to Q8 extends in the right direction in the drawing. The tip portions of the anode electrodes 31 of the thyristors Q1 to Q8 are distributed in the length direction of the conductor 21 and connected to the surface of the conductor 21.

In particular, the tip of the anode electrode 31 of the thyristor Q1 is connected to the surface of the first portion 21b of the conductor 21. The tip of the anode electrode 31 of the thyristor Q2 is connected to the surface of the second portion 21c of the conductor 21. The tips of the anode electrodes 31 of the thyristors Q2 to Q8 are connected to the end of the conductor 21 on the left side (conductor 22 side).

The cathode electrode 32 (second electrode) of each of the thyristors Q1 to Q8 extends in the left direction in the figure. Further, the tip portions of the cathode electrodes 32 of the thyristors Q1 to Q8 are distributed in the length direction of the conductor 22 and connected to the surface of the conductor 22.

The slit 21a is formed from the upper end of the conductor 21 to the vicinity of the tip of the anode electrode 31 of the thyristor Q3. The slit 21a is provided to increase the impedance of the current path of the thyristor Q1 and reduce variations in the currents Iq1 to Iq8 of the thyristors Q1 to Q8. A mechanism that can reduce variations in the currents Iq1 to Iq8 by the slit 21a will be described later. Each of the arms 12 and 13 has the same configuration as the arm 11.

FIG. 4 is a diagram showing variations in the currents Iq1 to Iq8 flowing through the thyristors Q1 to Q8 shown in FIG. In FIG. 4, a value Ia / 8 obtained by dividing the current Ia flowing through the arm 11 by the number of thyristors Q1 to Q8 is expressed as 100 (%). As can be seen from FIG. 4, the currents Iq1 to Iq8 flowing through the eight thyristors Q1 to Q8 are all approximately 100 (%), and the arm current Ia is almost equally divided into the eight thyristors Q1 to Q8. I understand that.

Therefore, in this arm 11, it is sufficient to use low-priced thyristors Q1 to Q8 having a rated current Ic of 120 (%) in FIG. 4, for example, and eight gate pulse signals are respectively applied to thyristors Q1 to Q8. Since the necessity of adjusting the phase of each gate pulse signal is reduced, the cost of the apparatus can be reduced.

FIG. 5 is a front view showing the configuration of the arm 14 shown in FIG. 1, and is a view compared with FIG. Referring to FIG. 5, arm 14 differs from arm 11 in that the directions of thyristors Q1 to Q8 are reversed, the upper end of conductor 22 constitutes anode terminal 14a, and the right end of conductor 23 is the cathode. This is the point constituting the terminal 14b.

The anode electrode 31 (second electrode) of each of the thyristors Q1 to Q8 extends in the left direction in the figure. The tip portions of the anode electrodes 31 of the thyristors Q1 to Q8 are distributed in the length direction of the conductor 22 and connected to the surface of the conductor 22.

The cathode electrode 32 (first electrode) of each of the thyristors Q1 to Q8 extends in the right direction in the drawing. The tip portions of the cathode electrodes 32 of the thyristors Q1 to Q8 are distributed in the length direction of the conductor 21 and connected to the surface of the conductor 21.

In particular, the tip of the cathode electrode 32 of the thyristor Q1 is connected to the surface of the first portion 21b of the conductor 21. The tip of the cathode electrode 32 of the thyristor Q2 is connected to the surface of the second portion 21c of the conductor 21. The tip portions of the cathode electrodes 32 of the thyristors Q2 to Q8 are connected to the left end portion of the conductor 21 (conductor 22 side). The configuration of each of the arms 15 and 16 is the same as that of the arm 14. Also in the arm 14, like the arm 11, the arm current Ia is almost equally divided into the eight thyristors Q1 to Q8.

FIG. 6 is a front view showing a configuration of an arm 11A which is a comparative example of the present embodiment, and is a diagram contrasted with FIG. Referring to FIG. 6, arm 11A is obtained by replacing conductor 21 of arm 11 of FIG. 3 with conductor 21A. The difference between the conductor 21A and the conductor 21 is that the slit 21a is not formed. The tip of the anode electrode 31 of the thyristor Q1 is connected to the left end of the conductor 21A, like the other thyristors Q2 to Q8.

FIG. 7 is a diagram showing variations in the currents Iq1 to Iq8 flowing through the thyristors Q1 to Q8 shown in FIG. 6, and is a diagram contrasted with FIG. In FIG. 7, similarly to FIG. 4, a value Ia / 8 obtained by dividing the current Ia flowing through the arm 11A by the number of thyristors Q1 to Q8 is expressed as 100 (%). As shown in FIG. 7, in this arm 11A, the current Iq1 of the first (topmost) thyristor Q1 has the maximum value (about 145%), and the current Iq2 of the second thyristor Q2 from the top has three stages. The current Iq3 of the fourth thyristor Q3 decreases in the order of the current Iq4 of the fourth-stage thyristor Q4, and the current Iq4 of the thyristor Q4 becomes the minimum value (80%).

The current Iq5 of the fifth stage thyristor Q5 is substantially the same as the current Iq4 of the thyristor Q4, the current Iq6 of the sixth stage thyristor Q6, the current Iq7 of the seventh stage thyristor Q7, and the eighth stage (bottom stage). The current Iq8 of the thyristor Q8 increases in the order. The current Iq1 (about 145%) of the first-stage thyristor Q1 is larger than the current Iq8 (about 105%) of the eighth-stage thyristor Q8.

Next, the mechanism by which the currents Iq1 to Iq8 of the thyristors Q1 to Q8 of the arm 11A vary as shown in FIG. When the current Iq in a certain current path changes, an electromotive force E is generated in another current path due to the mutual induction phenomenon. When the current Iq in a certain current path changes by ΔIq during the time Δt, the electromotive force E generated in the other current path is E = −M (ΔIq / Δt). The proportionality constant M is called mutual inductance.

In the arm 11A, there are eight current paths P1 to P8 including thyristors Q1 to Q8, respectively, and the currents Iq1 to Iq8 of the eight current paths P1 to P8 change simultaneously. When the currents Iq1 to Iq8 of the eight current paths P1 to P8 change, electromotive forces E1 to E8 are generated in the current paths P1 to P8, respectively. The electromotive force E of each current path P is caused by the current Iq of the other seven current paths P. The mutual inductance M between the two current paths P is larger as the distance between the two current paths P, that is, the distance between the two thyristors Q is smaller, and is smaller as the distance between the two thyristors Q is larger.

When the interval between two adjacent thyristors Q is d, the average distance D1 between the thyristor Q1 and the other seven thyristors Q2 to Q8 is D1 = (d + 2d + 3d + 4d + 5d + 6d + 7d) / 7 = 4d. The average distance D2 between the thyristor Q2 and the other seven thyristors Q1, Q3 to Q8 is D2 = (d + d + 2d + 3d + 4d + 5d + 6d) /7≈3.14d. The average distance D3 between the thyristor Q3 and the other seven thyristors Q1, Q2, Q4 to Q8 is D3 = (2d + d + d + 2d + 3d + 4d + 5d) /7≈2.57d. The average distance D4 between the thyristor Q4 and the other seven thyristors Q1 to Q3, Q5 to Q8 is D4 = (3d + 2d + d + d + 2d + 3d + 4d) /7≈2.29d.

The average distance D5 between the thyristor Q5 and the other seven thyristors Q1 to Q4 and Q6 to Q8 is D5 = D4≈2.29d. The average distance D6 between the thyristor Q6 and the other seven thyristors Q1 to Q5, Q7, Q8 is D6 = D3≈2.57d. The average distance D7 between the thyristor Q7 and the other seven thyristors Q1 to Q6, Q8 is D7 = D2≈3.14d. The average distance D8 between the thyristor Q8 and the other seven thyristors Q1 to Q7 is D8 = D1 = 4d.

In summary, D1 = D8 = 4d, D2 = D7≈3.14d, D3 = D6≈2.57d, and D4 = D5≈2.29d. Therefore, D1 = D8> D2 = D7> D3 = D6> D4 = D5. Assuming that the sum of the mutual inductances of each of the current paths P1 to P8 and the other seven current paths P is M1 to M8, the magnitude relationship of M1 to M8 is opposite to D1 to D8, and M1 = M8 <M2 = M7 <M3 = M6 <M4 = M5.

Since E = −M (ΔIq / Δt), the electromotive forces E1 to E8 generated in the current paths P1 to P8 when the currents Iq1 to Iq8 flowing in the current paths P1 to P8 change are respectively the current paths P1 to P8. Acts in the direction of decreasing the currents Iq1 to Iq8 flowing through the. Therefore, the magnitude relationship of the currents Iq1 to Iq8 of the current paths P1 to P8 is opposite to that of M1 to M8, and Iq1 = Iq8> Iq2 = Iq7> Iq3 = Iq6> Iq4 = Iq5. This magnitude relationship substantially coincides with the magnitude relationship of Iq1 to Iq8 shown in FIG.

FIG. 8 is a diagram showing a path P1 through which the current Iq1 of the uppermost thyristor Q1 flows and a path P8 through which the current Iq8 of the lowermost thyristor Q8 flows in the arm 11A of the comparative example. As shown in FIG. 8, the current Iq1 flows from the anode terminal 11a through the conductor 23, the conductor 21A, the thyristor Q1, and the upper end of the conductor 22 to the cathode terminal 11b. In contrast, the current Iq8 flows from the anode terminal 11a to the cathode terminal 11b through the conductor 23, the lower end of the conductor 21A, the thyristor Q8, and the entire conductor 22.

Therefore, the length of the current path P1 is shorter than the length of the current path P8. Further, the width of the conductor 21 through which the current Iq1 mainly flows is wider than the width of the conductor 22 through which the current q2 mainly flows. Therefore, the impedance Z1 of the current path P1 is smaller than the impedance Z2 of the current path P2. For this reason, the current Iq1 of the thyristor Q1 is larger than the current Iq8 of the thyristor Q8 (FIG. 7).

FIG. 9 is a diagram illustrating a path P1 through which the current Iq1 of the uppermost thyristor Q1 flows and a path P8 through which the current Iq8 of the lowermost thyristor Q8 flows in the arm 11 according to the embodiment. As shown in FIG. 9, the current Iq1 flows from the anode terminal 11a to the cathode terminal 11b through the conductor 23, the conductor 21, the first portion 21b, the thyristor Q1, and the upper end of the conductor 22. As shown in FIG. 8, the current Iq8 flows from the anode terminal 11a to the cathode terminal 11b through the conductor 23, the lower end of the conductor 21A, the thyristor Q8, and the entire conductor 21.

Therefore, compared to the comparative example, the current path P1 is longer and the width of the current path P1 is narrower. For this reason, the impedance Z1 of the current path P1 increases, the current Iq1 of the thyristor Q1 decreases, and the decrease is distributed to the other thyristors Q. In addition, the width of the current path P2 of the thyristor Q2 is narrowed by the slit 21a, and thus an increase in the current Iq2 of the thyristor Q2 is suppressed. As a result, as shown in FIG. 4, variations in the currents Iq1 to Iq8 of the eight thyristors Q1 to Q8 are reduced.

The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 Thyristor rectifier, 2 control device, 3 AC power supply, 4 load, 4a positive electrode, 4b negative electrode, T1-T3 AC input terminal, T4, T5 DC output terminal, 11-16, 11A arm, 11a-16a anode terminal, 11b- 16b cathode terminal, Q1-QN thyristor, 21-23, 21A conductor, 21a slit, 21b first part, 21c second part, 31 anode electrode, 32 cathode electrode.

Claims (11)

First and second conductors extending in the same direction;
1st to Nth rectifying elements sequentially arranged in the same direction as the first and second conductors and connected in parallel between the first and second conductors, wherein N is an integer of 2 or more Yes,
The rectifier, wherein the first conductor is formed with a slit that increases at least an impedance of a current path of the first rectifying element. The first electrodes of the first to Nth rectifying elements are dispersedly arranged in the length direction of the first conductor and connected to the first conductor,
2. The rectifier according to claim 1, wherein the second electrodes of the first to Nth rectifying elements are dispersedly arranged in the length direction of the second conductor and connected to the second conductor. The first and second electrodes of the first rectifying element are respectively connected to one ends of the first and second conductors,
The rectifier according to claim 2, wherein the slit is formed at one end of the first conductor. Each of the first and second conductors is formed in a strip shape,
The rectifier according to claim 3, wherein the slit is formed in a length direction of the first conductor from one end of the first conductor. The first and second conductors are arranged in parallel;
The first conductor is disposed in a width direction of the second conductor;
One end of the first conductor is divided by the slit into a first part on the opposite side of the second conductor and a second part on the second conductor side,
The rectifier according to claim 4, wherein the first electrode of the first rectifying element is connected to the first portion. The rectifier according to claim 5, wherein the first electrode of the second rectifying element is connected to the second portion. The rectifier according to claim 4, wherein the width of the first conductor is wider than the width of the second conductor. The rectifier rectifies an alternating voltage and supplies it to a load,
The alternating voltage is applied to the other end of the first conductor;
The rectifier according to claim 3, wherein the load is connected to one end of the second conductor. The rectifier rectifies an alternating voltage and supplies it to a load,
The alternating voltage is applied to the first conductor;
The rectifier of claim 1, wherein the load is connected to the second conductor. Each of the plurality of rectifying elements is a thyristor;
The rectifier according to claim 1, wherein the first and second electrodes of the plurality of rectifying elements are an anode and a cathode, respectively. Each of the plurality of rectifying elements is a thyristor;
The rectifier according to claim 1, wherein the first and second electrodes of the plurality of rectifying elements are a cathode and an anode, respectively.

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