JPH11191962A - Insulating power converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the overall size and cost by eliminating the conventionally required additional arm and substituting or reducing the size of a reactor. SOLUTION: An insulating power converter comprises a DC power supply 100 including a single phase AC power supply 62 and a single phase full-bridge converter, a smoothing capacitor 67, a single phase voltage type inverter 55, and a transformer 301 having AC output side insulated from a load 401. An energy absorbing element, i.e., a capacitor 501, and a DC resonance circuit are connected between the intermediate tap 303 of the primary winding 302 of the insulating transformer 301 and one end of the DC input terminal of the inverter 55. Power ripple generated on the power supply side is absorbed by the capacitor 501 by operating the inverter 55 in zero voltage vector mode and controlling the voltage across the capacitor 501.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called insulated converter in which an input side and an output side (power supply side and load side) are insulated by using a transformer. The present invention relates to a technique for reducing the capacity of a smoothing capacitor on the DC side of an inverter or a converter when a difference occurs between the smoothing capacitors.

[0002]

2. Description of the Related Art FIG. 19 shows a first prior art,
The circuit configuration described in the paper "715 Capacitance reduction of single-phase PWM converter with DC active filter function" published in the proceedings of the Annual Meeting of the Institute of Electrical Engineers of Japan is applied to an insulated DC-AC converter that insulates a power supply from a load. It was done. In the figure, 51 is a DC power supply, 52 is a semiconductor switching element Tr in which diodes are connected in anti-parallel.
1, a two-source chopper consisting of Tr2, 53 is a reactor, 54 is a capacitor, 55 is a single-phase voltage source inverter having semiconductor switching elements Tr3 to Tr6 in which diodes are connected in antiparallel, 56 is a transformer, and 57 is a diode bridge. Is a single-phase full-wave rectifier circuit, 58 is a smoothing capacitor, 59 is a single-phase voltage source inverter having semiconductor switching elements Tr7 to Tr10 in which diodes are connected in anti-parallel, and 60 is a load. Although a detailed description of the operation of this circuit is omitted, the basic operation is as follows.
In order to absorb the power ripple having a frequency twice as high as the power supply frequency generated on the input side, the voltage of the capacitor 54 is controlled by the two-quadrant chopper 52 to transfer energy, thereby reducing the capacity of the smoothing capacitor 58. .

FIG. 20 shows a second prior art, which is published in 1993 by the Institute of Electrical Engineers of Japan, Vol. 113-D, No. 9, p.
106-p.1107) The circuit configuration described in the paper "Suppressing DC Voltage Ripple in Single-Phase PWM Converters"
-Applied to an AC converter. In the figure,
61 is an LC composed of a reactor 53 and a condenser 54
This is a filter, and the other configuration is the same as that of FIG. The basic operation of this circuit is to absorb the power ripple having a frequency twice the power supply frequency generated on the input side of the inverter 59 by the LC filter 61 having the same resonance frequency, thereby reducing the capacitance of the smoothing capacitor 58. I have.

FIG. 21 shows a third prior art, which is a circuit described in the paper "79 DC power pulsation reduction method of single-phase voltage-type PWM converter" published in the proceedings of the National Convention of the Institute of Electrical Engineers of Japan. The configuration is applied to an insulated AC-DC converter. In the figure, 62 is a single-phase AC power supply, 64 is a single-phase full-bridge converter having semiconductor switching elements Tr11 to Tr14 in which diodes are connected in anti-parallel, 65 is a reactor, 66 is a semiconductor switching element Tr15 in which diodes are connected in anti-parallel. ,
Upper and lower arms composed of Tr16, 67 is a smoothing capacitor,
Reference numeral 68 denotes a reactor, and reference numeral 69 denotes a smoothing capacitor. In other configurations, the same components as those in FIGS. 19 and 20 are denoted by the same reference numerals. The basic operation of this circuit is that the current flowing through the reactor 65 is controlled by the upper and lower arms 66, so that the power ripple having a frequency twice the power supply frequency generated on the input side of the inverter 55 is absorbed by the reactor 65. 67 to reduce the capacity.

FIG. 22 shows an insulated AC-DC converter according to a fourth prior art. In this prior art,
A single-phase full-bridge converter 64 is connected to a secondary side of the transformer 56 via a reactor 63, and a load 60 is connected to a DC output side of the transformer 56 via a smoothing capacitor 69. The operation of the single-phase full-bridge converter 64 is publicly known and will not be described in detail.
The input current waveform is controlled in a sine wave form by appropriately short-circuiting the semiconductor switching element via 3 to obtain a desired DC voltage. In this case, the power input from the single-phase AC power supply 62 to the converter 64 is accompanied by power ripple having a frequency twice that of the power supply. Therefore, when outputting a constant power, an energy absorbing element for smoothing, here a large smoothing element is used. A capacitor 69 is required.

[0006]

In the first to third prior arts described above, a reactor is used on the DC side of the inverter 55, which hinders miniaturization of the device. Also,
In the first and third prior arts, it is necessary to add a pair of upper and lower arms on the DC side of the inverter 55, which hinders cost reduction. Further, in the second prior art, the resonance capacitor 5
4 is twice as large as the DC link voltage, which increases the size. Similarly, the fourth prior art also increases the size of the capacitor 69. In either case, there is a problem that the size of the entire device is impaired. Therefore, the present invention is to solve the above-mentioned various problems, and to provide an insulated power conversion device capable of reducing the capacity of a smoothing capacitor and reducing the size of the device by an inexpensive and simple configuration. is there.

[0007]

According to a first aspect of the present invention, there is provided a DC voltage source, and DC power is converted to AC power by an operation of a semiconductor switching element connected to the DC voltage source. An insulated power converter, comprising: a voltage-source inverter to be converted; and a transformer having a primary side connected to an AC output terminal of the inverter to insulate the load from a secondary side. An energy absorbing element is connected between the connected tap and one end of a DC input terminal of the inverter, and the inverter is operated in a zero voltage vector mode to control a voltage across the energy absorbing element. The power ripple generated on the source side or the load side is absorbed by the energy absorbing element.

FIG. 1 is a conceptual diagram of the invention described in claim 1, wherein 100 is a DC voltage source, 200 is an inverter such as a single-phase voltage type inverter, 300 is a transformer, and 400 is a load such as an AC load. , 500 are energy absorbing elements. Here, the energy absorbing element 500 is
As described in the twelfth and thirteenth aspects, it is constituted by a single capacitor or a series resonance circuit of a capacitor and a reactor. In FIG. 1, an intermediate tap is provided on the primary side (power supply side) of a transformer 300, and the energy absorbing element 500 includes the intermediate tap and the inverter 20.
0 is connected to one end of the DC input terminal. DC voltage source 100 uses a DC power source alone, or
A single-phase or multi-phase AC power supply may be converted to a DC power supply by a single-phase or multi-phase converter. Inverter 20
0 may be a single-phase or multi-phase voltage source inverter, and the number of phases of the transformer 300 is determined according to the number of output phases.

According to a second aspect of the present invention, there is provided an AC voltage source, a transformer having a primary side connected to the AC voltage source to insulate the load from the load, and a transformer connected between the secondary side of the transformer and the load. And a converter for converting AC power to DC power by the operation of the semiconductor switching element, in the insulated power conversion device, wherein a tap provided on the winding of the transformer and one end of a DC output terminal of the converter. By connecting an energy absorbing element between the two, and controlling the voltage between both ends of the energy absorbing element by operating the converter in the zero voltage vector mode, the power ripple generated on the AC voltage source side or the load side can be absorbed by the energy absorbing element. It is absorbed by the element.

FIG. 3 is a conceptual diagram of the invention described in claim 2, and the same components as those in FIG. 1 are denoted by the same reference numerals. In addition, 150 is an AC voltage source, 450 is a load such as a DC load, and 600 is a converter such as a single-phase full bridge converter. In the present invention, an intermediate tap is provided on the secondary side (load side) of the transformer 300, and the energy absorbing element 500 includes the intermediate tap and the converter 600.
Is connected between one end of the DC output terminal. The AC voltage source 150 is a single-phase AC power supply, a polyphase AC power supply, or the like.
Is determined.

FIG. 2 and FIG. 4 are conceptual diagrams of the invention described in claim 13, and embody the energy absorbing element 500 in FIG. 1 and FIG. That is, the energy absorbing element 500 includes the capacitor 501 and the reactor 502
And a series resonance circuit. Here, the core of reactor 502 may be shared with the core of transformer 300. In addition, as described in claim 12, the energy absorbing element 500 may be constituted by a single capacitor.

Referring to FIG.
By selecting a switching mode in which all upper and lower switching elements of each phase upper and lower arm are turned on, the inverter 200 can output a zero voltage vector. In the zero voltage vector mode, when viewed from the AC output terminal of the inverter 200, the capacitor 501 or the reactor 50
The voltage of 2 becomes a zero-phase voltage. The converter 6 shown in FIG.
By operating 00 in the zero voltage vector mode,
As seen from the AC input terminal of converter 600, the voltage of capacitor 501 or reactor 502 is a zero-phase voltage.

Since the zero-phase voltage output from the inverter 200 shown in FIG. 2 does not appear in the output line voltage of the transformer 300, it does not affect the load 400 side. In other words, considering the positive phase component, it operates as a conventional voltage source inverter with respect to the voltage applied to the transformer 300.
On the other hand, considering the zero-phase component, when outputting the zero voltage vector, the plurality of upper and lower arms of the inverter 200 can be regarded as one upper and lower arm that switches at a ratio of the zero voltage vector. The same operation can be performed. Also, the transformer 300
Can be regarded as a reactor having a value of leakage inductance.

That is, the inverter 200 shown in FIG.
The operation equivalent to the upper and lower arms 52 and 66 in the prior art shown in FIGS. 19 and 21 can be performed by the operation of the converter 600 in the zero voltage vector mode (control operation of the zero phase voltage). The voltage control of the energy absorbing element 500 can be performed without the addition. Therefore,
The power ripple generated between the voltage source side and the load side can be transferred to the energy absorbing element 500 without adding upper and lower arms and the like.
This makes it possible to reduce the capacity of the smoothing capacitor, reduce the size and weight of the device, and reduce the cost.

[0015] The invention as set forth in claims 3 and 4 is based on the first and second claims.
According to the third and fourth aspects of the present invention, the power ripple generated on the voltage source side is absorbed by the energy absorbing element. Of these, in claim 3, an intermediate tap is provided in the winding on the voltage source side of the transformer, and in claim 4, an intermediate tap is provided in the winding on the load side of the transformer. Further, according to the fifth and sixth aspects of the present invention, the power ripple generated on the load side is absorbed by the energy absorbing element.
Of these, in claim 5, an intermediate tap is provided in the winding on the voltage source side of the transformer, and in claim 6, an intermediate tap is provided in the winding on the load side of the transformer.

According to a seventh aspect of the present invention, in the insulation type power converter according to the first aspect, the DC voltage source is constituted by a single-phase AC power supply and a single-phase converter connected to an output side thereof. An energy absorbing element is connected between the intermediate tap of the voltage source side winding of the transformer and one end of the DC input terminal of the single-phase voltage source inverter, and this energy absorbing element removes power ripple generated on the DC voltage source side. It absorbs.

According to an eighth aspect of the present invention, in the insulated power converter according to the second aspect, the AC voltage source is composed of only a single-phase AC power source, and the energy absorbing element is
The energy absorbing element is connected between the intermediate tap of the load winding of the transformer and one end of the DC output terminal of the single-phase converter, and absorbs power ripple generated on the AC voltage source side.

According to a ninth aspect of the present invention, in the insulated power converter according to the first aspect, the DC voltage source is constituted only by the DC power source, and the energy absorbing element is disposed between the voltage source side windings of the transformer. The energy absorbing element is connected between the tap and one end of the DC input terminal of the single-phase voltage source inverter, and absorbs power ripple generated on the load side.

According to a tenth aspect of the present invention, in the insulated power converter according to the second aspect, the AC voltage source is composed of only a single-phase AC power source, and the energy absorbing element is a load source side winding of a transformer. , And one end of the DC output terminal of the single-phase converter, and this energy absorbing element absorbs power ripple generated on the load side.

According to an eleventh aspect of the present invention, there is provided a single-phase AC power supply, a single-phase full-bridge converter connected to the AC power supply, a single-phase voltage source inverter connected to a DC output terminal of the converter, and the inverter. A transformer whose primary side is connected to the AC output terminal of the converter to insulate the load from the load, and a reactor is connected between a middle point of a pair of upper and lower arms of the converter and an intermediate tap of a primary winding of the transformer. The power ripple is absorbed by the reactor by controlling the current of the reactor by operating the inverter in a zero voltage vector mode.

According to a fourteenth aspect of the present invention, in the insulated power converter according to the tenth aspect, the energy absorbing element is configured by connecting two series resonant circuits each including a capacitor and a reactor in parallel. However, the power ripples generated on the AC voltage source side and the load side by the respective resonance circuits can be respectively absorbed. Further, in the invention in which the energy absorbing element includes the reactor (the invention of claim 11, 13 or 14), as described in claim 15, the core of the reactor and the core of the transformer are shared (the reactor is provided inside the transformer). By incorporating and sharing the iron core), the transformer and the reactor can be integrated to further reduce the size.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, FIG. 5 is a circuit diagram showing a first embodiment of the present invention, and corresponds to the seventh and twelfth embodiments of the present invention. In the drawing, a single-phase AC power supply 62 is connected to a single-phase full-bridge converter 64 via a reactor 101 at both ends, as described above. The converter 64 includes semiconductor switching elements Tr11 to Tr14 in which diodes are connected in anti-parallel.
These AC power supply 62, reactor 101, and converter 64 constitute DC voltage source 100 in FIGS.

A smoothing capacitor 67 and a single-phase voltage source inverter 55 are connected between the DC output terminals of the converter 64. The inverter 55 includes semiconductor switching elements Tr3 to Tr6 having diodes connected in anti-parallel.
It is composed of An AC output terminal of the inverter 55 is connected to both ends of a primary winding (power supply side winding) 302 of the transformer 301, and an intermediate tap 303 of the primary winding 302 and one end of a DC input terminal of the inverter 55 (in FIG. A capacitor 501 as an energy absorbing element is connected between the capacitor 501 and the side terminal. Also, the transformer 30
A single-phase full-wave rectifier circuit 57 composed of a diode bridge is connected to both ends of one secondary winding (load-side winding) 304,
A load 401 such as a DC load is connected to the output side via a smoothing reactor 68 and a smoothing capacitor 69. In the above configuration, the converter 64 operates to make the input current waveform a sine wave. Since this control operation is known, its description is omitted here.

In this embodiment, a single-phase voltage source inverter 55
In the zero voltage vector mode. That is, there are two types of switching patterns for outputting a zero voltage vector by the single-phase voltage source inverter 55, that is, the case where all two sets of upper arms are made conductive and the case where all two sets of lower arms are made conductive. The form uses this degree of freedom. When a three-phase voltage source inverter is used as the voltage source inverter, a zero voltage vector is output by turning on all three sets of upper arms or turning on all three sets of lower arms.

Since the zero-phase voltage output from the inverter 55 does not appear in the output voltage, it does not affect the output voltage on the secondary side of the transformer 301, and there is no problem in supplying power to the load 401. Accordingly, the equivalent circuit for the positive phase focusing on the inverter 55 is as shown in FIG. 6, and the inverter 55 operates in the same manner as in the related art to apply an AC voltage to the primary side of the transformer 301. On the other hand, when considering the zero-phase component, it is as shown in FIG. 7, and the two upper and lower arms of the inverter 55 in FIG. 5 perform switching operation as if at the ratio of the zero voltage vector.
It can be considered as two upper and lower arms 55 '. here,
Reference numeral 302 ′ in FIG. 7 denotes a reactor having a value of leakage inductance of the transformer 301, and corresponds to the reactors 53 and 65 in FIGS. 19 and 21.

That is, by turning on the switching elements Tr3 and Tr5 of the upper arm of the inverter 55 or the switching elements Tr4 and Tr6 of the lower arm and operating in the zero voltage vector mode, the circuit of FIG. 7 is equivalently constituted. You. The upper and lower arms 5 in FIG.
5 ′, the upper and lower arms 52 in FIGS.
By performing the same chopper operation as in 66, power ripple generated on the power supply side can be absorbed by the capacitor 501 as an energy absorbing element, and the capacity and withstand voltage of the smoothing capacitor 67 can be reduced.

The current ripple of the capacitor 501 accompanying the switching of the inverter 55 is smoothed by the reactor 302 'having the value of the leakage inductance. However, when the leakage inductance alone is not enough, the intermediate tap 303 of the transformer 301 and the capacitor are connected. Further, a reactor sharing the iron core with the transformer 301 is further connected to the reactor 501. In FIG. 5, the smoothing reactor 68 provided on the load 401 side can be substituted by the leakage inductance of the transformer 301.

FIG. 8 shows a control circuit of the inverter 55. The inverter 55 is PWM-controlled, and the PWM pulse is generated by, for example, the control circuit shown in FIG. The method of creating a current command flowing through the capacitor 501, i.e., a zero-phase current command value i ₀ ^* , in order to reduce power ripple generated from the power supply side is described in the above-mentioned paper "715 DC Active It is known from "Reduction of the capacitance of a single-phase PWM converter having a filter function".

In FIG. 8, the deviation between the zero-phase current command value i ₀ ^* and the actual zero-phase current detection value i ₀ is determined by a current controller (ACR).
702 to obtain a zero-phase voltage command value v ₀ ^* . This zero-phase voltage command value v ₀ ^* is converted to the output voltage command value v _inv ^* of the inverter ^.
And -v _inv ^* via the sign inverter 701, and the result of the addition is input to the comparators 703 and 704, respectively. In these comparators 703 and 704, each input is compared with a triangular wave, and the output is inverted by the upper and lower arms, so that the switching element Tr3
To obtain a PWM pattern for Tr6. That is, the inverter 55 performs an operation in which the single-phase voltage source inverter and the two-quadrant chopper are overlapped by the change of the switching pattern. The former controls the positive-phase current, and the latter controls the zero-phase current.

Next, FIG. 9 is a circuit diagram showing a second embodiment. This embodiment corresponds to the seventh and thirteenth embodiments of the present invention. In this embodiment, the reactor 50 is connected between the intermediate tap 303 of the primary winding 302 of the transformer 301 and one end (negative terminal) of the DC input terminal of the inverter 55.
2 and a capacitor 501 are connected in series, and the reactor 502 and the capacitor 501 constitute a series resonance circuit as an energy absorbing element. The resonance frequency of this resonance circuit is selected to be twice the power supply frequency. By sharing the iron core of the reactor 502 and the iron core of the transformer 301, it is possible to further reduce the size by integrating the transformer 301 and the reactor 502. Other configurations are the same as those in FIG. Also in this embodiment, the single-phase full-bridge converter 64 operates to make the input current waveform a sine wave.

FIG. 10 shows a control circuit of the inverter 55, which is a circuit for obtaining a PWM pulse for the inverter 55. The difference from FIG. 8 is that the zero-phase voltage command value v ₀ ^* is directly applied to keep the zero-phase voltage constant. In FIG. 10, reference numeral 705 denotes a voltage controller (AVR), and other configurations are the same as those in FIG. According to the present embodiment, the withstand voltage of the resonance capacitor which is conventionally required to be twice or more the DC link voltage is changed to a value which is twice or more the zero-phase voltage. For example, if the zero-phase voltage command value v ₀ ^* is set so that the zero-phase voltage is の of the DC link voltage, the capacitor 5
The withstand voltage of 01 is improved to about 1/2 of the conventional value. in this case,
Even when the capacitance of the smoothing capacitor 67 is reduced, the power ripple appearing in the output is described in the above-mentioned 1993 Industrial Application Division of IEEJ (vol.113-D, No.9, p.1106 to p.1107). As is known by the article "Suppressing DC Voltage Ripple of Single-Phase PWM Converter", it can be reduced by the resonance capacitor 501 and the resonance reactor 502.

FIG. 11 is a circuit diagram showing a third embodiment, which corresponds to the eighth and twelfth embodiments of the present invention.
In this embodiment, the primary winding 306 of the transformer 305 is directly connected to the single-phase AC power supply 62, and both ends of the secondary winding 308 are connected to the AC input terminal of the single-phase full-bridge converter 64 via the reactor 63. I have. A smoothing capacitor 69 and a load 401 are connected to both ends of the DC output terminal of the converter 64. Further, a capacitor 503 as an energy absorbing element is connected between the intermediate tap 307 of the secondary winding 308 and one end (the negative terminal in the figure) of the DC output terminal of the converter 64. Converter 6
4 is connected to the transformer 305
Can be substituted by the leakage inductance. In this embodiment, the zero-phase voltage is controlled by operating the converter 64 in the zero-voltage vector mode, and the energy stored in the capacitor 503 is controlled. As a result, the power ripple generated at the secondary side of the transformer 305 at twice the frequency of the power supply can be absorbed by the capacitor 503, and the duty of the smoothing capacitor 69 can be reduced.

FIG. 12 shows a control circuit of the converter 64, which is a circuit for obtaining a PWM pulse for the converter 64. Since the control method of the single-phase full-bridge converter is publicly known, the description is omitted. However, the characteristic part is that the deviation between the zero-phase current command value i ₀ ^* and the zero-phase voltage detection value i ₀ i _S is input to a current controller (ACR) 702, and the zero-phase voltage command value v ₀ ^* output from the current controller 702 is inverted with the value output from the current controller (ACR) 706 and its sign. This is the point that is added to the calculated values. 705 is the DC voltage command value V of the smoothing capacitor 69
voltage controller (A) to which the deviation between _dc ^* and the detected value _Vdc is input.
A VR), the power supply voltage in phase with the sine wave (sinω _s t)
Is multiplied by the output of the voltage controller 705 to obtain the power supply current command value i _S ^* . The deviation between the power supply current command value i _S ^* and the detection value i _S is input to the current controller 706. Here, the method of creating the zero-phase current command value i ₀ ^* is known as described above.

FIG. 13 is a circuit diagram showing a fourth embodiment, which corresponds to the eighth and thirteenth embodiments of the present invention.
The configuration of this embodiment is generally similar to that of FIG.
The difference is that the capacitor 503 and the reactor 5 are connected between the intermediate tap 307 of the secondary winding 308 of the transformer 305 and one end (negative terminal) of the DC output terminal of the converter 64.
This is a point that a series resonance circuit as an energy absorbing element made of the element 04 is connected. This resonance frequency is selected to be twice the power supply frequency. A characteristic part of this embodiment is that, in the control circuit, a zero-phase current command value i ₀ ^* is added in FIG. 12, but a control circuit (not shown) of the present embodiment has a zero-phase voltage command value i ₀ ^*. v ₀ ^{* is set} to the current controller 706 of FIG.
Are directly added to the value output from the data and the value whose sign is inverted.

In this embodiment, the zero-phase voltage is controlled by operating the converter 64 in the zero-voltage vector mode, and the energy stored in the capacitor 503 and the reactor 504 is controlled. As a result, the power ripple generated at the secondary side of the transformer 305 at twice the frequency of the power supply can be absorbed by the capacitor 503 and the reactor 504, and the capacitance and withstand voltage of the smoothing capacitor 69 can be prevented from increasing.

FIG. 14 is a circuit diagram showing a fifth embodiment, which corresponds to the ninth and twelfth embodiments of the present invention. In this embodiment, a DC power supply 51, a single-phase voltage source inverter 55 connected to both ends thereof, a transformer 301 having a primary winding 302 connected to an AC output terminal thereof, and an AC input to a secondary winding 304 thereof are provided. Single-phase full-wave rectifier circuit 5 with connected terminals
7, the smoothing capacitor 58, and the single-phase voltage source inverter 5
The capacitor 501 as an energy absorbing element is connected between the intermediate tap 303 of the primary winding 302 of the transformer 301 and one end of the DC input terminal of the inverter 55 (the negative terminal in the figure). Note that 402
Is a load such as an AC load.

The control circuit of the inverter 55 of this embodiment is the same as that of FIG. 8 except that the zero-phase current command value i ₀ ^*
2 is set to a value that can absorb the power ripple generated by. By operating the inverter 55 in the zero voltage vector mode, the voltage of the capacitor 501 is controlled, and the power ripple generated from the load 402 is absorbed by the capacitor 501. Thus, the capacitance and withstand voltage of the smoothing capacitor 58 can be reduced.

FIG. 15 is a circuit diagram showing a sixth embodiment, and corresponds to the ninth and thirteenth aspects of the present invention. This embodiment is different from that of FIG. 14 except that a series resonance circuit including a capacitor 501 and a reactor 502 is connected between an intermediate tap 303 of a primary winding 302 of a transformer 301 and one end of a DC input terminal of an inverter 55. The configuration is the same as the embodiment. The resonance frequency of the resonance circuit is selected to be twice the output frequency of the inverter 55. If the iron core of the reactor 502 and the iron core of the transformer 301 are shared, the size can be reduced by integrating the two.

FIG. 16 is a circuit diagram showing a seventh embodiment, and corresponds to the tenth and twelfth embodiments of the present invention. In this embodiment, a single-phase voltage source inverter 59 is connected between the smoothing capacitor 69 and the load 401 in the embodiment of FIG. Note that the smoothing capacitor 58 in FIG. 16 is substantially the same as the smoothing capacitor 69 in FIG. 11, and the load 402 in FIG. 16 and the load 401 in FIG. 11 are different in whether they are AC loads or DC loads. Only. The PWM pulse for the converter 64 in this embodiment is shown in FIG.
The power ripple generated by the load 402 is absorbed by controlling the voltage of the capacitor 503 by the operation of the converter 64 in the zero voltage vector mode. Although not shown, a reactor is inserted between the intermediate tap 307 and the capacitor 503 to form a series resonance circuit, and the voltage between both ends is controlled by the operation of the converter 64 in the zero voltage vector mode to absorb power ripple. May be.

FIG. 17 is a circuit diagram showing an eighth embodiment, which corresponds to the tenth and fourteenth aspects of the present invention. The main part of this embodiment is the same as that of the embodiment of FIG. 16 except that the capacitor 503 and the intermediate tap 307 of the transformer 305 and one end (negative terminal) of the DC output terminal of the converter 64 are connected. A series resonance circuit including a reactor 504, a capacitor 505, and a reactor 506.
Is connected in parallel with a series resonance circuit composed of
Each of these series resonance circuits constitutes an energy absorbing element, and its resonance frequency is selected to be twice the power supply frequency and twice the output frequency of the inverter 59, respectively. That is, in the present embodiment, the single-phase AC power supply 62
And the power ripple generated from the load 402 are absorbed by the two series-connected resonant circuits connected in parallel. The operation of the converter 64 in the zero-voltage vector mode causes the capacitors 503 and 505 to operate.
Or the voltage across the two series resonant circuits,
The power ripple generated in the power supply 62 or the load 402 is absorbed.

FIG. 18 is a circuit diagram showing a ninth embodiment, which corresponds to the eleventh embodiment of the present invention. In this embodiment, a reactor 507 as an energy absorbing element is connected between a midpoint 641 of a pair of upper and lower arms of a single-phase full-bridge converter 64 and an intermediate tap 303 of a transformer 301. 5 is the same as the one in which the capacitor 501 is removed.
The converter 64 operates so that the input current waveform becomes a sine wave, but this operation is well-known, and the description is omitted. The PWM pulse for the inverter 55 is shown in FIG.
Can be obtained by the control circuit. In this embodiment, by operating the inverter 55 in the zero voltage vector mode, the current flowing through the reactor 507 is controlled to absorb the power ripple, and the capacity of the smoothing capacitor 67 provided on the DC input side of the inverter 55 is reduced. Let me. The method of creating the zero-phase voltage command value is described in
The paper “7
9 DC power pulsation reduction system of single-phase voltage-type PWM converter ". Also in the present embodiment, if the core of the reactor 507 is shared with the transformer 301, the transformer 301 and the reactor 507 can be downsized by integration.

In each of the above embodiments, the energy absorbing element may be connected between the intermediate tap of the transformer and the other end of the DC input terminal of the inverter, or between the other end of the DC output terminal of the converter. .

[0043]

As described above, according to the present invention, the voltage type inverter or converter is operated in the zero voltage vector mode to control the voltage across the energy absorbing element composed of a single capacitor or a series resonance circuit. The power ripple on the power supply side or the load side can be absorbed by the energy absorbing element in place of the pair of upper and lower arms added, thereby reducing the capacity and withstand voltage of the smoothing capacitor. In this way, the duty of the smoothing capacitor is reduced, and the reactor is replaced with a transformer or its iron core is shared, so that the entire device can be reduced in size, weight, and cost.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of the invention described in claim 1;

FIG. 2 is a conceptual diagram of the invention described in claim 13;

FIG. 3 is a conceptual diagram of the invention described in claim 2;

FIG. 4 is a conceptual diagram of the invention described in claim 13;

FIG. 5 is a circuit diagram showing the first embodiment.

FIG. 6 is an equivalent circuit diagram of a positive phase component focusing on the voltage source inverter of FIG. 5;

FIG. 7 is an equivalent circuit diagram of a zero-phase component focusing on the voltage source inverter of FIG.

FIG. 8 is a control circuit diagram of the first embodiment.

FIG. 9 is a circuit diagram showing a second embodiment.

FIG. 10 is a control circuit diagram of a second embodiment.

FIG. 11 is a circuit diagram showing a third embodiment.

FIG. 12 is a control circuit diagram of a third embodiment.

FIG. 13 is a circuit diagram showing a fourth embodiment.

FIG. 14 is a circuit diagram showing a fifth embodiment.

FIG. 15 is a circuit diagram showing a sixth embodiment.

FIG. 16 is a circuit diagram showing a seventh embodiment.

FIG. 17 is a circuit diagram showing an eighth embodiment.

FIG. 18 is a circuit diagram showing a ninth embodiment.

FIG. 19 is a circuit diagram showing a first conventional technique.

FIG. 20 is a circuit diagram showing a second conventional technique.

FIG. 21 is a circuit diagram showing a third conventional technique.

FIG. 22 is a circuit diagram showing a fourth conventional technique.

[Explanation of symbols]

Reference Signs List 100 DC voltage source 150 AC voltage source 200 Inverter 300 Transformer 400, 450 Load 500 Energy absorbing element 501, 503, 505 Capacitor 502, 504, 506, 507 Reactor 600 Converter 51 DC power supply 55, 59 Single-phase voltage-type inverter 55 'Up and down Arm 57 Single-phase full-wave rectifier circuit 58, 67, 69 Smoothing capacitor 62 Single-phase AC power supply 63, 68, 101 Reactor 64 Single-phase full-bridge converter 301, 305 Transformer 302, 306 Primary winding 302 'Leakage inductance 303, 307 Intermediate Tap 304, 308 Secondary winding 401, 402 Load 701 Sign inverter 702, 706 Current controller 703, 704 Comparator 705 Voltage controller Tr3 to Tr6, Tr11 to Tr14 Switching element

Claims (15)

[Claims] 1. A DC voltage source, a voltage type inverter connected to the DC voltage source and converting DC power into AC power by the operation of a semiconductor switching element, and a secondary side having a primary side connected to an AC output terminal of the inverter. And a transformer that insulates between a tap on a winding of the transformer and one end of a DC input terminal of the inverter. By connecting and controlling the voltage across the energy absorbing element by operating the inverter in the zero voltage vector mode, power ripple generated on the DC voltage source side or the load side is absorbed by the energy absorbing element. Characterized insulated power converter. 2. An AC voltage source, a transformer having a primary side connected to the AC voltage source for insulation between a load, and an operation of a semiconductor switching element connected between a secondary side of the transformer and the load. And a converter that converts AC power to DC power by using a power converter. An energy absorbing element is connected between a tap provided on a winding of the transformer and one end of a DC output terminal of the converter. By operating the converter in the zero voltage vector mode to control the voltage across the energy absorbing element, power ripple generated on the AC voltage source side or the load side is absorbed by the energy absorbing element. Insulated power converter. 3. The insulated power converter according to claim 1, wherein the power ripple generated on the voltage source side is reduced by an energy absorbing element having one end connected to an intermediate tap of a voltage source side winding of the transformer. An insulated power converter characterized by absorption. 4. The insulated power converter according to claim 1, wherein the power ripple generated on the voltage source side is absorbed by an energy absorbing element having one end connected to an intermediate tap of a load side winding of the transformer. An insulated power converter. 5. The insulated power converter according to claim 1, wherein an energy absorbing element having one end connected to an intermediate tap of a voltage source side winding of the transformer absorbs power ripple generated on a load side. An insulated power converter. 6. The insulated power converter according to claim 1, wherein the energy ripple generated on the load side is absorbed by an energy absorbing element having one end connected to an intermediate tap of a load side winding of the transformer. An insulated power converter. 7. The insulated power conversion device according to claim 1, wherein the DC voltage source includes a single-phase AC power supply and a single-phase converter connected to an output side thereof, and the energy absorbing element includes Connected between the intermediate tap of the voltage source side winding of the transformer and one end of the DC input terminal of the single-phase voltage source inverter, and that this energy absorbing element absorbs power ripple generated on the DC voltage source side. Characterized insulated power converter. 8. The insulated power converter according to claim 2, wherein the AC voltage source is constituted by only a single-phase AC power source, and the energy absorbing element is connected to an intermediate tap of a load-side winding of a transformer. An insulated power converter, which is connected between one end of a DC output terminal of a phase converter and the energy absorbing element absorbing a power ripple generated on an AC voltage source side. 9. The insulated power converter according to claim 1, wherein the DC voltage source is composed of only a DC power source, and the energy absorbing element is a single-phase with a middle tap of a voltage source side winding of a transformer. It is connected between one end of the DC input terminal of the voltage source inverter and this energy absorbing element is
An insulated power converter that absorbs power ripple generated on the load side. 10. The insulated power converter according to claim 2, wherein the AC voltage source is constituted by only a single-phase AC power source, and the energy absorbing element is connected to an intermediate tap of a load-side winding of a transformer. An insulated power conversion device connected between one end of a DC output terminal of a phase converter and an energy absorbing element for absorbing power ripple generated on a load side. 11. A single-phase AC power supply, a single-phase full-bridge converter connected to the AC power supply, and a single-phase voltage source inverter connected to a DC output terminal of the converter.
A transformer whose primary side is connected to the AC output terminal of the inverter to insulate the load from the load; and a midpoint between a pair of upper and lower arms of the converter and an intermediate tap of a primary winding of the transformer. An insulated power converter, wherein a power ripple is absorbed by the reactor by connecting a reactor and controlling the current of the reactor by operating the inverter in a zero voltage vector mode. 12. The insulated power converter according to claim 1, wherein the energy absorbing element is a capacitor. 13. The insulated power conversion device according to claim 1, wherein the energy absorbing element is a series resonance circuit including a capacitor and a reactor. apparatus. 14. The insulated power converter according to claim 10, wherein the energy absorbing element is configured by connecting two series resonance circuits each including a capacitor and a reactor in parallel,
An insulated power converter, wherein each resonance circuit absorbs power ripples generated on an AC voltage source side and a load side. 15. The insulated power converter according to claim 11, wherein an iron core of a reactor and a core of a transformer that constitute the energy absorbing element are shared. Insulated power converter.