JP2721915B2 - Rectifier circuit device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a rectifier circuit device in which a plurality of bridge rectifier circuits are connected in parallel.

[Conventional technology]

A conventional 12-phase thyristor rectifier circuit is configured as shown in FIG. In this rectifier circuit, first and second thyristor three-phase bridge rectifier circuits 5, 6 are connected to three-phase AC power supply terminals 1, 2, 3 via an insulating transformer 4, and these three-phase bridge rectifiers are connected. Circuits 5 and 6 are connected via an inter-phase reactor 7, one output terminal 8 is connected to the midpoint of the inter-phase reactor 7, and the other output terminal 9 is connected to the negative output line of each rectifier circuit 5 and 6. ing. Accordingly, the load 10 is supplied with electric power from both the first and second thyristor three-phase bridge rectifier circuits 5 and 6. The transformer 4 includes a star-connected primary winding 11, a star-connected first secondary winding 12, and a triangular-connected second secondary winding 13. First
The output voltage of the secondary winding 12 and the output voltage of the second secondary winding 13 have a phase difference of π / 6 from each other. Accordingly, a 12-phase rectified output is equivalently obtained from the two sets of three-phase bridge rectifier circuits 5 and 6, and the harmonic component of the input current can be reduced.
First and second thyristor three-phase bridge rectifier circuits 5, 6
Is connected to a current detector. These outputs are provided to a control circuit (not shown) which forms control pulses for the thyristors of the first and second thyristor three-phase bridge rectifier circuits 5,6. In this conventional circuit, the return current does not flow because the insulating transformer 4 is used. Therefore, the control based on the current detection is performed not for preventing the circulating current but for preventing the current from flowing to the first and second thyristor three-phase bridge rectifier circuits 5 and 6 in one direction.

[Problems to be solved by the invention]

The circuit of FIG. 8 comprises a pair of secondary windings 1 insulated from each other.
Since two sets of rectifier circuits 5 and 6 are connected to 2 and 13, there is a feature that no circulating current flows. However, insulated transformers are less efficient, larger, larger, heavier and more expensive than non-insulated transformers.

Therefore, an object of the present invention is to provide a rectifier circuit device that can reduce harmonic components of an AC input current and that can be reduced in size and cost.

[Means for Solving the Problems] The present invention for solving the above problems and achieving the above object can obtain an output voltage having a larger number of phases than the number of phases of the AC power supply. And at least two second output terminals for obtaining a second output voltage having a phase different from the phase of the first output voltage. A non-insulating transformer formed so as not to insulate between the first and second output terminals; a first bridge-type control rectifier circuit connected to the first output terminal of the non-insulating transformer; A second output terminal connected to the second output terminal of the non-isolated transformer;
A bridge-type control rectifier circuit, a first reactor connected between a positive output line of the first bridge-type control rectifier circuit and a positive output line of the second bridge-type control rectifier circuit, A second reactor connected between a negative output line of the first bridge-type control rectifier circuit and a negative output line of the second bridge-type control rectifier circuit;
A positive output terminal connected to an intermediate point of the first reactor, a negative output terminal connected to an intermediate point of the second reactor, and a positive output terminal of the first and second bridge control rectifier circuits. First and second positive-side current detectors for detecting the currents of the output lines of the first and second bridge-type control rectifier circuits, respectively. The first and second negative current detectors and the first and second positive current detectors are configured such that the currents of the positive output lines of the first and second bridge control rectifier circuits are balanced with each other. The first and second responsive to the output.
A positive-side control circuit for controlling at least one positive-side control element of the bridge-type control rectifier circuit;
In response to the outputs of the first and second negative current detectors so that the currents on the negative output lines of the bridge-type control rectifier circuit of the first and second bridge-type control rectifier circuits are balanced. And a negative control circuit for controlling at least one of the negative control elements.

It is preferable that the first bridge-type control rectifier circuit is fixedly controlled and the second bridge-type control rectifier circuit is controlled based on the current balance detection signal.

Further, the input current of the first and second bridge-type control rectifier circuits can be detected, and the output current can be obtained by calculation.

〔Example〕

Next, a thyristor rectifier circuit device according to an embodiment of the present invention will be described with reference to FIGS. However, in FIG. 1, substantially the same parts as those in FIG. 8 are denoted by the same reference numerals, and description thereof will be omitted.

In this embodiment, AC power supply terminals 1, 2, and 3 and first and second three-phase bridge rectifier circuits (hereinafter simply referred to as first and second
A non-insulating transformer 20 having an extended side triangular connection is connected between the bridge circuit 5 and 6. The non-insulating transformer 20 is a single-winding transformer and includes extension windings 21a, 21b, 22a, 2 in addition to the main windings 21, 22, 23 of the first, second and third phases.
2b, 23a and 23b. The windings 21, 21a, 21b are in phase, the windings 22, 22a, 22b are in phase, and the windings 23, 23a, 23b are in phase. The three-phase power terminals 1, 2, and 3 have the same number of turns.
Connected to the connection point of the triangular connection of the two main windings 21, 22, 23,
The first and second bridge circuits 5, 6 are connected to the respective extension windings 21a, 2a.
Output terminals U ₁ , U ₂ , V ₁ , V ₂ , 1b, 22a, 22b, 23a, 23b
Connected to W ₁ and W ₂ . Transformer output terminals U _1, V _1, W ₁
Has a difference of + π / 12 with respect to the phases of the input power supply terminals 1, 2, and 3, respectively, and the transformer output terminals U ₂ ,
The voltage phases of V ₂ and W ₂ have a difference of −π / 12 with respect to the phases of the input power supply terminals 1, 2 and 3.

The connection midpoint between the positive thyristors S ₁ , S ₂ , S _{3 of} the first bridge circuit 5 and the negative thyristors S ₄ , S ₅ , S ₆ is connected to the output terminals U ₁ , V ₁ , W ₁ of the transformer 20, respectively. Connected, the positive thyristors S ₇ , S ₈ , S _{9 of} the second bridge circuit 6 and the negative thyristor S
_10, S _11, connection point between S ₁₂ is the output terminal U ₂ of the transformer 20,
They are connected to V ₂ and W ₂ respectively. The positive output lines 5a and 6a of the first and second bridge circuits 5 and 6 are connected to a positive output terminal 8 via an inter-phase reactor 7, and the negative output lines 5b and 6b are also negatively output via an inter-phase reactor 24. Terminal 9
It is connected to the. The positive and negative output terminals 8 and 9 are connected to the center taps of the interphase reactors 7 and 24. The reactors 7 and 24 are connected to the first bridge circuit 5.
Side and the second bridge circuit 6 side can be divided into two reactors respectively. In this case, output terminals 8 and 9 are connected to a connection midpoint between the two reactors. Current detectors 14, 15, 25, 26 are connected to the output lines 5a, 5b, 6a, 6b of the first and second bridge circuits 5, 6, respectively.

The detection line of each current detector 14, 15, 25, 26 is a control circuit
Positive current balance detection circuit 28 for current balance compensation of 27
And the negative side current balance detection circuit 29.

The control circuit 27 includes a positive and negative current balance detection circuit 28,
In addition to 29, it has an output voltage command value input terminal 30, first, second, and third phase control circuits 31, 32, 33, adders 34, 35, and a reference clock circuit 36. Output voltage command value input terminal 30
And a first phase control circuit 31 a reference clock circuit 36 is connected, when the output voltage command is constant, a fixed positive side and negative side thyristors S ₁ to S ₆ of the first Buritsuji circuit 5 Drive in phase.

The first adder circuit 34 is connected to the positive current balance detection circuit 28 and the output voltage command value input terminal 30, and supplies the second phase control circuit 32 with the added value of the signals supplied from these.
The second adder circuit 35 is connected to the negative current balance detection circuit 29 and the output voltage command value input terminal 30, and supplies the third phase control circuit 33 with the added value of the signals supplied from these.

The second phase control circuit 32 generates a signal for controlling the positive thyristors S ₇ , S ₈ , S ₉ of the second bridge circuit 6,
The phase control circuit 33 generates a signal for controlling the negative thyristors S ₁₀ , S ₁₁ and S ₁₂ of the second bridge circuit 6. The second phase control circuit 32 includes first and second positive output lines 5a and 6a.
Thyristors S ₇ , S ₈ ,
Controls S _9, the third phase control circuit 33 controls the negative side thyristors S _10, S _11, S ₁₂ so that the first and second negative output lines 5b, 6b of the current balance.

The reference clock circuit 36 provides reference timing for the first, second, and third phase control circuits 31, 32, and 33.

FIG. 2 shows the first positive current balance detecting circuit 28 and the adding circuit 34 in detail. The first input terminal 41 is connected to the first positive-side current detector 14, and the second input terminal 42 is connected to the second positive-side current detector 15. Resistors 43 and 44 are connected between the pair of input terminals 41 and 42, and a connection midpoint between them is connected to one input terminal of an operational amplifier 46 via a resistor 45. An integrating capacitor 47 and a resistor 48 are connected between one input terminal and an output terminal of the operational amplifier 46, and the other input terminal is grounded. The first and second input terminals 41 and 42 are connected to the first and second positive current detectors 14 and 15 respectively.
Are connected in opposite polarities. Therefore, when the detection values of the first and second positive current detectors 14 and 15 are equal, the potential at the connection point 49 between the resistors 43 and 44 becomes zero, and when the current becomes unbalanced, the potential becomes positive or negative. Potential.

The adding circuit 34 includes resistors 50, 51, 52, 53 and an operational amplifier 54, and adds the output voltage of the balance detecting circuit 28 to the voltage supplied from the output voltage command value input terminal 30 and outputs the result.

The negative current balance detection circuit 29 and the addition circuit 35
The configuration is the same as that of the positive current balance detection circuit 28 and the addition circuit 34 shown in FIG.

FIG. 3 shows the first phase control circuit 31 of FIG. 1 in detail. The first phase control circuit 31, a sawtooth wave generating circuit for generating six sawtooth wave in response to the thyristor S ₁ to S ₆ of the first Buritsuji circuit 5 61 62 63 64 , 65, 66. The six sawtooth wave generating circuits 61 to 66 generate six sawtooth waves shown in FIGS. 5A to 5F based on the reference clock supplied from the reference clock circuit 36. Fifth
The sawtooth waves shown in FIGS. 6A to 6F correspond to the first bridge circuit 5.
Since it corresponds to the six thyristors S ₁ to S ₆ of
As shown in the drawing, they have a phase difference of 2π / 3 from each other. Note that the positive thyristors S ₁ , S ₂ , S ₃ and the negative thyristor S ₄ ,
S ₅ and S ₆ are in an anti-phase relationship and have a phase difference of π from each other.

One input terminal of each of the first to sixth comparators 67, 68, 69, 70, 71, 72 is connected to the output voltage command value input terminal 30, and the other input terminal is connected to the first to sixth sawtooth waves. It is connected to generating circuits 61-66. Therefore, the comparator 67
To 72, control pulses corresponding to the period in which the sawtooth wave crosses the output voltage command value are generated, and these control pulses are supplied to the thyristor S ₁ via the drive circuits 73, 74, 75, 76, 77, 78. It applied to the gate of the to S _6, thyristors S ₁ to S ₆ starts conduction in synchronization with the rising of the control pulses.

FIG. 4 shows the second and third phase control circuits 32 and 33.
The first phase control circuit 32 includes three sawtooth wave generating circuits 81, 8
2, 83, three comparators 84, 85, 86 and three drive circuits 87, 88, 89. Sawtooth wave generation circuit 81, 8
Sawtooth wave for the thyristor S _7, S _8, S ₉ shown in FIG. 5 (G) (H) (I ) generated from 2,83 comparator 8
4, 85, and 86, are compared with the first control signal supplied from the first adder circuit 34, and a control pulse is generated corresponding to a period in which the sawtooth wave crosses the first control signal. And
The signal is supplied to the positive thyristors S ₇ , S ₈ and S ₉ of the second bridge circuit 6.

A third phase control circuit 33 is thyristors _{S 10, S 11, S 12} 3 pieces of the sawtooth wave generating circuit 90, 91 and 92 corresponding to, and three comparators 93, 94 and 95, three drive Circuits 96, 97, 98
Consisting of The sawtooth waves shown in FIGS. 5 (J), (K) and (L) which are generated from the sawtooth wave generation circuits 90, 91 and 92 are input to the comparators 93, 94 and 95 and supplied from the second addition circuit 35. The second control signal is compared with the second control signal, and a control pulse is generated corresponding to the period when the sawtooth wave crosses the second control signal, and the negative side thyristors S ₁₀ , S ₁₁ , S ₁₂ of the second bridge circuit 6 are generated. Given to the gate.

Sawtooth wave of FIG. 5 which corresponds to the thyristor S ₇ to S ₁₂ of the second Buritsuji circuit 6 (G) ~ (L) Fifth diagram corresponding to the thyristor S ₁ to S ₆ of the first Buritsuji circuit 5 (A) ~
It advances by π / 6 from the sawtooth wave of (F).
Since the voltages applied to the _twelve thyristors S _{1 to} S ₁₂ of the first and second bridge circuits 5 and 6 from the side extension triangular connection transformer 20 are given with a phase difference of π / 6, 12 of the sawtooth wave shown in FIG. 5 (a) ~ (L) will be that corresponding to the phase difference between the voltage of the thyristors S ₁ to S _12.

Assuming that the voltage value of the output voltage command value input terminal 30 is fixed, the thyristor of the first bridge circuit 5
S _{1 to} S ₆ conduct at a fixed phase, but the second bridge circuit 6
Of thyristor S ₇ to S ₁₂ to not conduct a fixed phase, conducts in phase in response to changes in the level of the control signal supplied from the adder circuit 34 and 35 in Figure 4. That is, when there is an imbalance between the currents of the current of the first positive output line 5a and the second positive output line 6a is thyristors S ₇ as this is compensated, S _8, S ₉ And the conduction phase of the first
If there is an imbalance between the current of the negative output line 5b and the current of the second negative output line 6b, the conduction phases of the thyristors S ₁₀ , S ₁₁ , and S ₁₂ are adjusted so as to compensate for the imbalance. Change. Accordance connexion, the positive side thyristors S _1, S _2, S ₃ of the first Buritsuji circuit 5, and the load 10, a negative side thyristors S _10, S _11, S ₁₂ of the second Buritsuji circuit 6, a transformer 20 Circulating current in a closed circuit consisting of: If the transformer 20 is non-insulated and the current is unbalanced, a circulating current flows through the closed circuit, and the harmonic components of the current waveforms at the input power supply terminals 1, 2, and 3 increase.

If the voltage of the output voltage command value input terminal 30 changes, the phases of the _twelve thyristors S _{1 to} S ₁₂ change simultaneously,
Stabilization control or regulation of the output voltage is achieved.

(Modification)

The present invention is not limited to the above-described embodiment, and for example, the following modifications are possible.

(1) As shown in FIG. 6, current detectors 14a, 15a, 25a, 26a are added to the positive and negative output lines 5a, 5b, 6a, 6b of the first and second bridge circuits 5, 6, respectively. Then, current balance detection circuits 100 and 101 are also added, and also in the current balance detection circuits 100 and 101, the current balance is detected in the same manner as the current balance detection circuits 28 and 29, and this is added to the addition circuits 102 and 103.
May be added to the output voltage command value and input to the phase control circuits 31a and 31b. Phase control circuit 31a, 31b are those divided into groups of Figure 3 thyristors S ₁ phase control circuit 31 of, S _2, S ₃ and _{S 4, S 5, S 6} , the phase control circuit of FIG. 4 32,
It is formed similarly to 33. In FIG. 6 and FIGS. 9 to 11 described below, substantially the same parts as those in FIG. 1 are denoted by the same reference numerals.

As shown in FIG. 6, the first and second bridge circuits 5,
6, the same operation and effect as in the circuit of FIG. 1 can be obtained even when the current is balanced. The current detector 14
a, 15a, 25a, 26a are not provided independently, and the current detectors 14, 1
5, 25, and 26 may also be used.

(2) Instead of the side extension triangular connection transformer 20 in FIG.
Fork-connected non-insulating transformer 20a shown in FIG. 7 can be used. In FIG. 7, the windings a ₂ ,
The voltages of b ₂ and c ₂ have a phase difference of 120 degrees, and the windings a ₁ and c ₂
a ₂ , a ₃ , a ₄ are in phase, windings b ₁ , b ₂ , b ₃ , b ₄ are in phase, windings
c ₁ , c ₂ , c ₃ , c ₄ are in phase. In FIG. 7, the illustration of the current detection circuit and the control circuit is omitted.

(3) Instead of detecting the currents on the output lines 5a, 5b, 6a, 6b of the first and second bridge circuits 5, 6, the currents on the input side of the first and second bridge circuits 5, 6 are detected. A current detector may be provided for each input line, and a circuit for calculating the currents of the output lines 5a, 5b, 6a, and 6b of the bridge circuits 5, 6 based on the outputs of the current detectors may be provided.

(4) A fixed voltage can be applied to the input terminal 30.

(5) The reference clock is supplied to each of the sawtooth wave generating circuits 61 to 66, 81.
Instead supplied to ～83,90～92 may create sawtooth waves remaining thyristors S ₂ to S ₁₂ based on the sawtooth wave thyristor S _1.

(6) The number of output phases of the non-isolated transformer can be increased or decreased.

[Effects of the Invention] According to the invention of each claim, miniaturization and cost reduction are achieved by using a non-insulating transformer, and the first and second output voltages having a phase difference are reduced by the first and second output voltages. By notifying not only the harmonic component of the AC input current but also the first and the second by rectifying by the two bridge-type control rectifier circuits and supplying a DC voltage to the common positive and negative output terminals, By improving the balance of the output current of the bridge-type control rectifier circuit, the circulating current (circulating current) is suppressed, and harmonic components based on the circulating current are reduced.

According to the second aspect of the present invention, a plurality of control signals having different phases can be easily and accurately obtained by the plurality of sawtooth-wave generating circuits and the plurality of comparators.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a thyristor rectifier circuit device according to an embodiment of the present invention, FIG. 2 is a circuit diagram showing a current balance detection circuit and an addition circuit of FIG. 1, and FIG. 3 is a first circuit diagram of FIG. FIG. 4 is a block diagram showing the second and third phase control circuits of FIG. 1, and FIG. 5 is a block diagram showing the output of the sawtooth wave generating circuit of FIGS. 3 and 4. FIG. 6 is a circuit diagram showing a modified thyristor rectifier circuit device, FIG. 7 is a circuit diagram showing another modified thyristor rectifier circuit device, and FIG. 8 is a conventional thyristor rectifier circuit device. FIG. 1, 2, 3 ... power supply terminal, 5 ... first thyristor three-phase bridge rectifier circuit, 6 ... second thyristor three-phase bridge rectifier circuit, 7 ... inter-phase reactor, 14, 15 ... current detector , 20 ... non-insulating transformer, 24 ... interphase reactor,
25, 26 ... current detector, 28 ... positive side current balance detection circuit, 29 ... negative side current balance detection circuit, 30 ... output voltage command value input terminal, 31 ... first phase control circuit, 32 ... A second phase control circuit, 33... A third phase control circuit.

Claims (3)

(57) [Claims] An output voltage having more phases than the number of phases of an AC power supply can be obtained, and at least two first output voltage terminals for obtaining a first output voltage; and A second output terminal for obtaining a second output voltage having a phase different from the phase of the first output voltage, wherein the second output terminal is formed so as not to insulate between the first and second output terminals. An isolation transformer, a first bridge-type control rectifier circuit connected to the first output terminal of the non-isolation transformer, and a second bridge-type control rectifier circuit connected to the second output terminal of the non-isolation transformer A rectifier circuit; a first reactor connected between a positive output line of the first bridge-type control rectifier circuit and a positive output line of the second bridge-type control rectifier circuit; Negative output of bridge control rectifier A second reactor connected between a line and a negative output line of the second bridge-type control rectifier circuit; a positive output terminal connected to an intermediate point of the first reactor; A negative output terminal connected to the midpoint of the reactor of the first and second types, and first and second positive-side current detections for detecting currents of positive output lines of the first and second bridge-type control rectifier circuits, respectively. A first and a second negative current detector for detecting a current of a negative output line of each of the first and second bridge control rectifier circuits; and a first and a second bridge type. At least one of the first and second bridge-type control rectifier circuits in response to the outputs of the first and second positive current detectors such that the currents on the positive output lines of the control rectifier circuit balance each other. Control one positive control element Side control circuit; and the second control circuit in response to the output of the first and second negative side current detectors so that the currents of the negative output lines of the first and second bridge control rectifier circuits are balanced with each other. A negative control circuit for controlling at least one negative control element of the first and second bridge-type control rectifier circuits. 2. A first and a second saw-tooth voltage having a phase difference corresponding to a conduction phase difference between a positive control element and a negative control element for controlling the first bridge control rectifier circuit. First and second saw-tooth waveform generating circuits, and comparing the output voltage command value with the first and second saw-tooth waveform voltages to control the positive side of the first bridge-type control rectifier circuit. And first and second comparators for outputting first and second control signals for controlling the element and the negative-side control element, wherein the positive-side control circuit is provided with the second bridge type. A third sawtooth wave having the same phase difference as the first sawtooth voltage with respect to the first sawtooth voltage for controlling the positive control element of the control rectifier circuit; A third sawtooth wave generating circuit for generating a voltage, and the first and second positive current detectors A positive-side current balance detection circuit that outputs a signal indicating the difference between the outputs as a positive-side current balance detection signal; a first addition circuit that adds the positive-side current balance detection signal to the output voltage command value; Of the adder circuit of
A third comparator that outputs a third control signal for controlling a positive-side control element of the second bridge-type control rectifier circuit by comparing the sawtooth voltage with the negative-side control circuit. Has the same phase difference as the phase difference between the first and second output voltages with respect to the second sawtooth voltage in order to control the negative control element of the second bridge-type control rectifier circuit. A fourth sawtooth wave generating circuit for generating a fourth sawtooth wave voltage having the following, and a signal indicating the difference between the outputs of the first and second negative current detectors are output as a negative current balance detection signal. A negative current balance detection circuit, a second addition circuit for adding the negative current balance detection signal to the output voltage command value, an output of the second addition circuit and the fourth
And a fourth comparator that compares the sawtooth voltage of the second control signal and outputs a fourth control signal for controlling a negative control element of the second bridge-type control rectifier circuit. Item 8. The rectifier circuit device according to Item 1. 3. An output voltage having a greater number of phases than the number of phases of the AC power supply, wherein at least two first output voltage terminals for obtaining a first output voltage; and A second output terminal for obtaining a second output voltage having a phase different from the phase of the first output voltage, wherein the second output terminal is formed so as not to insulate between the first and second output terminals. An isolation transformer, a first bridge-type control rectifier circuit connected to the first output terminal of the non-isolation transformer, and a second bridge-type control rectifier circuit connected to the second output terminal of the non-isolation transformer A rectifier circuit; a first reactor connected between a positive output line of the first bridge-type control rectifier circuit and a positive output line of the second bridge-type control rectifier circuit; Negative output of bridge control rectifier A second reactor connected between a line and a negative output line of the second bridge-type control rectifier circuit; a positive output terminal connected to an intermediate point of the first reactor; A negative output terminal connected to an intermediate point of the reactor, current detection means for detecting input currents of the first and second bridge-type control rectifier circuits, respectively; and Current calculating means for calculating the currents of the positive and negative output lines of the first and second bridge-type control rectifier circuits, respectively; and the first and second bridge-type control rectifier circuits based on the positive current obtained by the current calculating means. A positive-side control circuit that controls at least one positive-side control element of the first and second bridge-type control rectifier circuits so that currents of the positive output lines of the control rectifier circuit balance each other; The first and second bridge-type control rectifier circuits such that the currents on the negative output lines of the first and second bridge-type control rectifier circuits are balanced with each other based on the negative current obtained by the means. And a negative control circuit for controlling at least one negative control element.