JP2006081259A - Rectifying circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rectifying circuit that can further reduce harmonics, can catch up a delay of a transient build-up current, and can obtain ideal DC power less in the distortion of an input current. <P>SOLUTION: The rectifying circuit comprises: a first three-phase full-wave rectifier 1 to which three-phase AC power is inputted; a transformer 3 to which the three-phase AC power is inputted and which transforms the three-phase AC power and outputs it; and a three-phase full-wave rectifier 2 to which an output of the transformer 3 is inputted. The rectifying circuit obtains DC power that is obtained by synthesizing outputs of the first three-phase full-wave rectifier 1 and the second three-phase full-wave rectifier 2. The transformer 3 is a non-insulated transformer. The rectifying circuit makes each phase of the three-phase AC power advance in a range of approximate 40° to approximate 80°, and outputs a phase voltage of the three-phase AC power in a range of approximate 85V to approximate 95V. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rectifier circuit that rectifies three-phase AC power to obtain DC power, and more particularly, to a rectifier circuit that reduces harmonics and is reduced in size and weight.

Conventionally, many rectifier circuits that convert three-phase AC power into DC power employ a three-phase full-wave rectifier having six rectifying elements in a bridge configuration.
In such a three-phase full-wave rectifier, the rectifying element that is energized sequentially is switched every 60 ° (one cycle of the AC power supply is 360 °), and a DC voltage is output. Since the voltage includes a voltage ripple with a large amplitude having a period 6f which is six times the power supply frequency f, this also becomes a harmonic on the AC power supply side and causes various troubles.
Therefore, various countermeasures for reducing this harmonic have been proposed.

As one of such countermeasures, for example, there is a technique for reducing harmonics by using two three-phase full-wave rectifiers and shifting the phase of the three-phase AC power input to each three-phase full-wave rectifier. .
For example, Japanese Patent Laid-Open No. 9-135570 (Patent Document 1) has a single primary winding of delta connection and two secondary windings of delta connection and star connection as shown in FIG. A multiple rectifier circuit including a three-phase transformer and two three-phase full-wave rectifier circuits is disclosed.
In this multiple rectifier circuit, the delta connection terminal of the primary winding of the transformer is connected to the three-phase AC power source, and the delta connection terminal and star connection of the secondary winding are connected to the AC side of the respective three-phase full-wave rectification terminals. Connect to the terminal. According to this circuit, the corresponding phases of the input voltage of the three-phase full-wave rectifier circuit have a phase difference of 30 ° from each other. Voltage ripples having a frequency six times the frequency f of the power supply, the same amplitude with each other, and a phase difference of 30 ° from each other are included.
As a result, when the outputs of the three-phase full-wave rectifier circuit are overlapped, the ripples of the DC output voltage of the rectifier circuit are superposed in opposite phases to cancel each other, resulting in a small vibration voltage ripple of 12 times the frequency 12f. It becomes possible to reduce harmonics.
Further, as shown in FIG. 13, the above-mentioned Patent Document 1 discloses a circuit that achieves the same effect while reducing the number of transformers in the above-described multiple rectifier circuit, while reducing the cost and size. Has been.

Japanese Patent Laid-Open No. 2002-10646 (Patent Document 2) discloses a technique for reducing harmonics with a small transformer capacity by using a non-insulated single-winding transformer instead of the insulating transformer. Yes.
JP-A-9-135570 (page 2-4, Fig. 1-4) JP 2002-10646 A (page 4-5, FIG. 10-14)

  However, in the rectifier circuits disclosed in Patent Document 1 and Patent Document 2 described above, the transformer input / output voltage ratio and the input / output voltage phase difference are set without considering the impedance of the system and the DC reactor of the converter. Therefore, there is a problem that a delay occurs in the rise of the current.

  The present invention has been made to solve the above-described problem, and further reduces harmonics and eliminates the delay in rising of the current, thereby obtaining ideal DC power with less distortion of the AC side input current. An object of the present invention is to provide a rectifier circuit that can be used.

In order to solve the above problems, the present invention employs the following means.
The present invention includes a first three-phase full-wave rectifier that receives three-phase AC power, a non-insulating transformer that receives the three-phase AC power, transforms and outputs the three-phase AC power, And a second three-phase full-wave rectifier to which the output of the isolation transformer is input, and rectification for obtaining DC power by combining the outputs of the first three-phase full-wave rectifier and the second three-phase full-wave rectifier The non-insulated transformer advances the phase of each phase of the three-phase AC power in a range of about 40 ° to about 80 °, and the phase voltage of the three-phase AC power is about 85V to about Provided is a rectifier circuit that outputs in the range of 95V.

According to the present invention, the three-phase AC power from the AC power source is directly input to the first three-phase full-wave rectifier and also input to the non-insulating converter. The first three-phase full-wave rectifier rectifies and outputs the input three-phase AC power. The non-insulating converter advances the phase of each phase of the input three-phase AC power in the range of about 40 ° to about 80 ° and transforms the phase voltage of the three-phase AC power to the range of about 85V to about 95V. And output. The three-phase AC power output from the non-insulating converter is rectified and output by the second three-phase full-wave rectifier.
In this case, the voltage ratio and the phase difference of the input / output voltage by the non-insulated converter are set in consideration of eliminating the delay in the rise of the current due to the leakage inductance in addition to the reduction of harmonics. Therefore, by combining the output power of the first and second three-phase full-wave rectifiers, it is possible to obtain direct-current power with less harmonic components in which ripples included in each other's output power are offset, and current It is possible to obtain ideal DC power with less distortion of the AC-side input current by eliminating the delay of the rise of.

The non-insulated converter advances the phase of each phase of the three-phase AC power in a range of about 52 ° to about 72 ° and transforms the phase voltage of the three-phase AC power to a range of about 85V to about 93V. Output is preferable.
In this way, by configuring the transformer, it is possible to further reduce the distortion of the AC side input current while avoiding an increase in size of the transformer.
The non-insulating converter advances the phase of each phase of the three-phase AC power in a range of about 59 ° to about 61 °, and transforms the phase voltage of the three-phase AC power to a range of about 88V to about 91V. Output is more preferable.
Thus, by configuring the transformer, it is possible to obtain ideal DC power in which distortion of the AC side input current is greatly reduced while avoiding an increase in size of the transformer.

  The present invention includes a first three-phase full-wave rectifier to which three-phase AC power is input, an insulation transformer that receives the three-phase AC power, transforms and outputs the three-phase AC power, and the insulation transformer And a second three-phase full-wave rectifier to which the output of the detector is input, and a rectifier circuit for obtaining DC power obtained by synthesizing the outputs of the first three-phase full-wave rectifier and the second three-phase full-wave rectifier The isolation transformer advances a phase of each phase of the three-phase AC power in a range of about 10 ° to about 50 °, and a phase voltage of the three-phase AC power in a range of about 115V to about 130V. A rectifier circuit that outputs the signal is provided.

According to the present invention, the three-phase AC power from the AC power source is directly input to the first three-phase full-wave rectifier and also input to the isolation converter. The first three-phase full-wave rectifier rectifies and outputs the input three-phase AC power. The isolation converter advances the phase of each phase of the input three-phase AC power in a range of about 10 ° to about 50 °, and transforms the phase voltage of the three-phase AC power to a range of about 115V to about 130V. Output. The three-phase AC power output from the isolation converter is rectified and output by the second three-phase full-wave rectifier.
In this case, the voltage ratio and the phase difference between the input and output voltages by the isolation converter are set in consideration of eliminating the delay in the rise of current due to leakage inductance in addition to the reduction of harmonics. Therefore, by combining the output power of the first and second three-phase full-wave rectifiers, it is possible to obtain direct-current power with less harmonic components in which ripples included in each other's output power are offset, and current It is possible to obtain an ideal DC power with less distortion of the input current by eliminating the delay of the rise of.

The isolation converter advances the phase of each phase of the three-phase AC power in a range of about 20 ° to about 40 °, and transforms the phase voltage of the three-phase AC power to a range of about 118V to about 128V. It is preferable to output.
Thus, by configuring the transformer, it is possible to further reduce harmonics while avoiding an increase in size of the transformer.
The isolation converter advances the phase of each phase of the three-phase AC power in a range of about 25 ° to about 35 °, and transforms the phase voltage of the three-phase AC power to a range of about 120V to about 126V. It is more preferable to output.
Thus, by configuring the transformer, it is possible to obtain ideal DC power in which distortion of the AC side input current is greatly reduced while avoiding an increase in size of the transformer.

  Further, the rectifier circuit of the present invention is suitable for an air conditioner or the like, and by adopting this rectifier circuit, it is possible to obtain high-quality DC power and to reduce the size of the entire apparatus. It becomes possible.

  According to the rectifier circuit of the present invention, it is possible to obtain an ideal DC power with less distortion of the input current, in which the harmonics are further reduced and the delay of the rise of the current is eliminated.

  Hereinafter, embodiments of a rectifier circuit of the present invention will be described in the order of [first embodiment] and [second embodiment] with reference to the drawings.

[First Embodiment]
FIG. 1 is a single-line diagram showing a configuration of a rectifier circuit according to the first embodiment of the present invention.
As shown in FIG. 1, the rectifier circuit according to the present embodiment is a 12-phase rectifier circuit including two three-phase full-wave rectifiers 1 and 2 and a converter 3.
One three-phase full-wave rectifier (hereinafter referred to as “first three-phase full-wave rectifier”) 1 is directly connected to an AC power source 4. Another three-phase full-wave rectifier (hereinafter referred to as “second three-phase full-wave rectifier”) 2 is connected to an AC power supply 4 via a converter 3. The outputs of the first and second three-phase full-wave rectifiers 1 and 2 are connected in parallel to the DC line.

In the 12-phase rectifier circuit having such a configuration, the three-phase AC power output from the AC power supply 4 is directly input to the first three-phase full-wave rectifier 1 and also input to the transformer 3. . The first three-phase full-wave rectifier 1 rectifies and outputs the input three-phase AC power. At this time, the output DC power includes a ripple having a frequency six times the frequency f of the three-phase AC power.
On the other hand, the converter 3 has a phase of input three-phase AC power (hereinafter referred to as “primary side power”) in the range of about 40 ° to about 80 °, preferably in the range of about 52 ° to about 72 °. More preferably, in the range of about 59 ° to about 61 ° and the voltage value is in the range of about 85V to about 95V, preferably in the range of about 85V to about 93V, more preferably from about 88V to about Step down to the range of 91V and output.
Three-phase AC power (hereinafter referred to as “secondary power”) output from the transformer 3 is input to the second three-phase full-wave rectifier 2. The three-phase full-wave rectifier 2 rectifies and outputs three-phase AC power. Here, the DC power output from the second three-phase full-wave rectifier 2 includes a ripple having the same frequency as the ripple included in the output of the first three-phase full-wave rectifier 1. Due to the action of the vessel 3, the amplitude and phase of the ripples are different.
Therefore, the DC power output from the first and second three-phase full-wave rectifiers 1 and 2 is combined to cancel the ripple, and the DC power with less harmonics (hereinafter referred to as the combined DC power). Is referred to as “combined DC power”) from the output terminal to another device (not shown). Also, harmonic distortion is reduced in the input current on the AC side.

  In the rectifier circuit as described above, in the present embodiment, attention is paid to the transformer 3, and the phase and voltage value of the secondary power output from the transformer 3 are reduced in harmonic inductance, leakage inductance, and the like. The transformer 3 is configured so as to have a value that eliminates the delay of the current rise caused by the current. As a result, it is possible to obtain combined DC power with a favorable current rise while maintaining the effect of reducing the harmonics of the input current.

Hereinafter, the transformer 3 according to the present embodiment will be described in detail with reference to the drawings.
FIG. 2 shows a converter vector diagram when the transformer 3 is constituted by a non-insulating converter, and FIG. 3 shows an example of a winding structure of the converter 3.
In FIG. 2, O is a neutral point, and vectors extending from the neutral point O to the respective vertices R1, S1, and T1 of the triangle are primary side phase voltages V _OR1 , V _OS1 , V _OT1 , that is, three-phase alternating current. The phase voltage of the three-phase alternating current power from the power supply 4 (refer FIG. 1) is shown.
In the converter 3, the phases of the primary side phase voltages V _OR1 , V _OS1 , V _OT1 are advanced by θ and the secondary side phase voltages V _OR2 , V _OS2 , V _OT2 are stepped down to a predetermined voltage value V _1. Is output.

For example, as shown in FIG. 3, the transformer 3 is constituted by a single-winding transformer with an auxiliary winding, and has a structure in which one set of auxiliary winding is provided corresponding to each main winding. The terminals R1, S1, and T1 of the main winding are respectively connected to the power supply lines R1, S1, and T1 shown in FIG.
In FIG. 3, R0 provided between R1 and S1 of the main winding is connected to R0 of the auxiliary winding. Similarly, S0 provided between S1 and T1 of the main winding and T0 provided between T1 and R1 are also connected to S0 and T0 of the corresponding auxiliary winding. Secondary windings R2, S2, and T2 are output terminals, which are connected to the input terminals of the second three-phase full-wave rectifier 2 shown in FIG.
In the main winding, the winding ratio between R1-S1 and R1-R0 is proportional to the voltage ratio between the line voltage V _LIN and the secondary voltage V ₂ shown in FIG. Further, the winding number of the auxiliary windings R2-R0 is proportional to the auxiliary winding voltage V ₃ shown in FIG.
Secondary phase voltage V _{OR @ 2} in the case of performing such a connection, V _OS2, V _OT2 and a phase difference θ between the primary-side phase voltage _{V OR1, V OS1, V OT1} , 2 -side phase voltage voltage the value _{V 1} was shown below (1) is expressed by equation (2).

As shown in the above equations (1) and (2), the secondary side phase voltages V _OR2 , V _OS2 and V _OT2 are determined by the secondary voltage V ₂ and the auxiliary winding voltage V ₃ shown in FIG. . The secondary voltage V ₂ and the auxiliary winding voltage V ₃ is because it is determined by transformer winding turns of the transformer 3, the secondary-side phase voltages V _OR2, V _OS2, V _OT2 is harmonic reduction and The transformer 3 is configured by adjusting the turns ratio of the main winding of the transformer of the transformer 3 and the number of turns of the auxiliary winding so as to take an optimum value in order to eliminate the delay in rising of the current. .
In the present embodiment, the transformer vector diagram of a transformer 3 as described above, the secondary-side phase voltages V _OR2, V _OS2, V _OT2 the primary side phase voltages V _OR1, V _OS1, the phase difference between V _OT1 theta is A value in the range of about 40 ° to about 80 °, preferably the phase difference θ is in the range of about 52 ° to about 72 °, more preferably the phase difference θ is in the range of about 59 ° to about 61 °, and voltage value _{V 1} is about 85V to about 95V, preferably from about 85V to a range of about 93V, more preferably, to take a value in the range of from about 88V to about 91V, transformer main winding and the auxiliary transformer 3 Configure the winding.
Further, in connection shown in FIG. 3, the secondary voltage _{V 2} is about 35V to the range of about 112V, preferably in the range of from about 70V to about 100 V, more preferably to take a value in the range of from about 80V to about 83V , and the scope of the auxiliary winding voltage V ₃ from about 31V to about 38V, more preferably to range from about 37V to about 38V, constituting the main winding and an auxiliary winding of the transformer 3 trans.

Next, an embodiment of the rectifier circuit shown in FIG. 1 will be described.
[Example 1]
In the present embodiment, the transformer 3 in a primary-side phase voltage V _OR1, V _OS1, V _OT1 and secondary phase voltage V _{OR @ 2,} V _OS2, the phase difference θ and the secondary-side phase voltages V and V _{OT2 OR2,} V _OS2, changing the voltage value V ₁ of the V _OT2, were checked for distortion rate included from the AC power source 4 to the input current to the rectifier circuit.
In this embodiment, in the rectifier circuit shown in FIG. 1, the phase voltage and frequency of the three-phase AC voltage of the AC power source 4 are 200 V and 60 Hz, the power source resistance and the inductance (phase) are 0.19 Ω and 0.23 mH, the transformer 3 The change of the distortion rate when the resistance and inductance of 0.33Ω, 0.19 mH, the DC smoothing inductance is 1.2 mH, the DC smoothing capacitor is 4.7 mF, and the load power is 10.7 kW is confirmed.

4, from the AC power source 4 with respect to a change in the phase difference θ between the primary-side phase voltage V _OR1, V _OS1, V _OT1 and secondary phase voltage V _OR2, V _OS2, V _OT2 to rectifier circuit It is a figure which shows the change of the distortion rate (%) of an input current (refer FIG. 1).
FIG. 5 shows voltage values V ₁ , secondary voltage V ₂ , and auxiliary winding voltage V _{3 of} secondary side phase voltages V _OR2 , V _OS2 , V _OT2 when the curve shown in FIG. 4 is obtained. 2 and FIG. 3).
4, the horizontal axis represents the phase difference theta (°) between the primary-side phase voltage V _OR1, V _OS1, V _OT1 and secondary phase voltage _{V OR2, V OS2, V OT2} , the vertical axis represents the distortion of the input current Rate (%). 5, the horizontal axis represents the phase difference between the primary-side phase voltage V _OR1, V _OS1, V _OT1 and secondary phase voltage _{V OR2, V OS2, V OT2} θ (°), the vertical axis represents voltage (V) It is.
As shown in FIG. 4 and FIG. 5, when the phase difference θ is in the range of about 40 ° to about 80 ° and the phase voltage V ₁ is in the range of about 85V to about 95V, the distortion rate is 10.7% or less, It was confirmed that the distortion rate can be improved as compared with the conventional model (minimum distortion rate 10.7%). Thereby, DC power with less harmonics of the input current can be obtained.
Furthermore, when the phase difference θ is in the range of about 52 ° to about 72 °, the distortion rate can be 9% or less, and when the phase difference θ is in the range of about 59 ° to about 61 °, the distortion rate can be reduced. It was confirmed that it was possible to reduce the level to nearly 8%.

Further, as can be seen from the above-described equations (1) and (2) and FIG. 2, the phase difference θ and the voltage value V ₁ are determined by the secondary voltage V ₂ and the auxiliary winding voltage V ₃ . In this embodiment, as shown in FIG. 5, from about 35V to the range of about 112V to _{V 2,} when the _{V 3} in the range of from about 31V to about 38V, the secondary-side phase voltages V _{OR @ 2,} V _OS2, V It was confirmed that _OT2 was within the above-mentioned preferable range.
In particular, the value of _{V 3} is, with respect to _{V 3} of the conventional model 1 (about 31V), it was confirmed that it is about 10V higher.
Thus, by increasing the V _3, it is possible to obtain the following effects.
(A) Voltage Compensation The current flowing through the transformer of the transformer 3 is determined by V _Tr shown in FIG.
Here, V _Tr is expressed by the following equation (3) using the secondary voltage V ₂ and the auxiliary winding voltage V ₃ .

Thus, V _Tr can be increased by increasing V ₃ . By increasing V _Tr , it is possible to compensate for the voltage drop due to the impedance of the transformer winding.

(B) Phase compensation In FIG. 2, when current I ₂ flows from R ₂ to T ₁ , R-phase, S-phase, and T-phase transformer currents I _R , I _S , and _IT are expressed by the following equation (4) It is expressed as follows.

As is apparent from the above equation (4), when V ₃ is increased, the S-phase phase current I _S increases more than the R-phase phase current I _R. When considering the entire three-phase AC power, it has advanced the S-phase current I _S to T-phase current I _T of the peak current. Here, the S-phase current I _S to be greater than the R-phase current I _R, it is possible to advance the phase of the current flowing in the transformer of the transformer 3. Thereby, the phase delay due to the impedance of the transformer winding can be compensated.

As described above, according to the rectifier circuit according to this embodiment, the transformer 3 has the phase θ of each phase voltage V _OR1 , V _OS1 , V _OT1 of the three-phase AC power in the range of about 40 ° to about 80 °. , Preferably in the range of about 52 ° to about 72 °, more preferably in the range of about 59 ° to about 61 °, and the phase voltage of the three-phase AC power is in the range of about 85V to about 95V, preferably about Since the voltage is output after being transformed into the range of 85V to about 93V, and more preferably within the range of about 88V to about 91V, the voltage drop due to the impedance of the transformer winding can be compensated and the phase of the current flowing through the transformer can be Can proceed.
This makes it possible to eliminate the delay in the rise of the current due to leakage inductance while maintaining the harmonic reduction effect, so ideal DC power with greatly reduced distortion on the AC side input current. Can be obtained.

When priority was given to the purpose of reducing the capacity of the transformer over the purpose of reducing the distortion rate, the characteristics shown in FIG. 6 could be confirmed.
6, the transformer capacity of the transformer 3 with respect to a change in the phase difference θ between the primary-side phase voltage V _OR1, V _OS1, V _OT1 and secondary phase voltage V _OR2, V _OS2, V _OT2 FIG. In this characteristic diagram, the distortion rate (%) is shown in parentheses. In this figure, the horizontal axis represents the phase difference theta (°) between the primary-side phase voltage V _OR1, V _OS1, V _OT1 and secondary phase voltage _{V OR2, V OS2, V OT2} , the ordinate transformer for power supply power It is a ratio (%) of the electric power capacity.
From FIG. 6, the phase difference θ is in the range of about 20 ° to about 80 ° and the secondary side phase voltage value is in the range of 80V to about 100V, while maintaining the distortion rate at about 16%, It was confirmed that the content could be reduced to 40% or less. In particular, when the phase difference θ takes a value of about 20 °, it was confirmed that the transformer has the minimum capacity while maintaining a low distortion rate of 16.8%. The phase voltage at this time was about 95V to about 100V.

[Second Embodiment]
Next, a rectifier circuit according to a second embodiment of the present invention will be described.
In the rectifier circuit of the present embodiment, the transformer 3 shown in FIG. 1 is constituted by an insulating converter, not a non-insulating converter.
In this case, the transformer 3 causes the phase of the input primary power to range from about 10 ° to about 50 °, preferably from about 20 ° to about 40 °, more preferably from about 25 ° to about 50 °. While proceeding in the range of 35 °, the voltage value is stepped down to the range of about 115V to about 130V, preferably about 118V to about 128V, more preferably about 120V to about 126V, and output.
By configuring the winding of the isolation transformer so that the secondary power is output in the above range, it is possible to compensate for the voltage drop due to the impedance of the transformer winding, and to reduce the current flowing through the transformer. The phase can be advanced.
As a result, as in the case of the above-described non-insulated transformer, it is possible to eliminate the delay in the rise of current due to leakage inductance while maintaining the harmonic reduction effect, and the AC side input current can be reduced. It is possible to obtain ideal DC power with reduced distortion.

Next, examples of the rectifier circuit according to the present embodiment will be described.
[Example 2]
In this embodiment, the phase difference θ between the primary side phase voltage and the secondary side phase voltage in the transformer 3 and the voltage value of the secondary side phase voltage are changed, and the input current from the AC power source to the rectifier circuit is changed. The included distortion rate was confirmed.
In this embodiment, in the rectifier circuit shown in FIG. 1, the phase voltage and frequency of the three-phase AC voltage of the AC power source 4 are 200 V and 60 Hz, the power source resistance and the inductance (phase) are 0.19 Ω and 0.23 mH, the transformer 3 The change of the distortion rate when the resistance and inductance of 0.33Ω, 0.19 mH, the DC smoothing inductance is 1.2 mH, the DC smoothing capacitor is 4.7 mF, and the load power is 10.7 kW is confirmed.

FIG. 7 shows the change in distortion rate (%) of the input current (see FIG. 1) from the AC power supply 4 to the rectifier circuit when the phase difference θ between the primary side phase voltage and the secondary side phase voltage is changed. FIG.
FIG. 8 is a diagram showing the voltage value of the secondary side phase voltage when the curve shown in FIG. 7 is obtained. FIG. 9 is a diagram showing the relationship between the phase difference θ and the secondary side phase voltage when the distortion rate is suppressed to about 14% or less while maintaining the transformer capacity of the transformer 3 at about 43% or less.
In FIG. 7, the horizontal axis represents the phase difference θ (°) between the primary side phase voltage and the secondary side phase voltage, and the vertical axis represents the distortion rate (%) of the input current. 8 and 9, the horizontal axis represents the phase difference θ (°) between the primary side phase voltage and the secondary side phase voltage, and the vertical axis represents the voltage (V).

As shown in FIGS. 7 and 8, when the phase difference θ is in the range of about 20 ° to about 35 ° and the secondary side phase voltage is in the range of about 120 to about 124 V, the distortion rate is 8% or less. Further, it was confirmed that when the phase difference θ is in the range of about 25 ° to about 35 ° and the secondary side phase voltage is about 122 V, the distortion rate is reduced to about 6%. . In particular, it was confirmed that a minimum distortion rate of 6.48% was obtained when the phase difference θ was about 30 ° and the secondary side phase voltage was about 122V. It can be seen that this distortion rate is extremely smaller than the minimum distortion rate of 13.8% of the conventional model (conventional example 2).
Further, as shown in FIG. 9, the distortion ratio is maintained at about 14% or less in the range where the phase difference θ is about 10 ° to about 50 ° and the secondary side phase voltage is about 115V to about 130V. However, it was confirmed that the capacity of the transformer could be reduced to less than 43%.

In addition, when priority was given to the objective of reducing the capacity | capacitance of a transformer rather than the objective of reducing a distortion rate, the characteristic as shown in FIG.10 and FIG.11 has been confirmed.
FIG. 10 is a diagram illustrating a change in the power capacity of the transformer of the transformer 3 when the phase difference θ between the primary side phase voltage and the secondary side phase voltage is changed. In this characteristic diagram, the distortion rate (%) is shown in parentheses. FIG. 11 is a diagram showing the voltage value of the secondary side phase voltage when the curve shown in FIG. 10 is obtained.
In FIG. 10, the horizontal axis represents the phase difference θ (°) between the primary side phase voltage and the secondary side phase voltage, and the vertical axis represents the ratio (%) of the power capacity of the transformer to the power source power. In FIG. 11, the horizontal axis represents the phase difference θ (°) between the primary side phase voltage and the secondary side phase voltage, and the vertical axis represents the voltage (V).
As shown in FIG. 10, the phase difference θ is in the range of about 10 ° to about 50 °, the secondary side phase voltage is about 114V to about 120V, and the capacitance is kept at 38% while maintaining the distortion rate at about 15%. % Can be confirmed. In particular, when the phase difference θ is about 50 ° and the secondary side phase voltage is about 117 V, it has been confirmed that the capacity can be reduced to nearly 33% while suppressing the distortion rate to about 16%.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the specific structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
First, in the above-described first and second embodiments, a rectifier circuit is configured by one transformer 3 and two three-phase full-wave rectifiers. However, the configuration is not limited to this configuration example. A configuration comprising a first three-phase full-wave rectifier directly connected, N (N is an integer of 1 or more) transformers, and N second full-wave rectifiers connected to the converter It is also good.
Secondly, the method of connecting the transformers constituting the converter 3 is not limited to the example shown in FIG. 3, and in FIG. 2, the positional relationship of O, R1, S1, T1, and R2, S2, T2 is If maintained, other winding structures can be taken by changing the position of R0, S0, T0.

It is a single wire connection diagram of the rectifier circuit which concerns on the 1st Embodiment of this invention. It is a converter vector diagram when the transformer which concerns on the 1st Embodiment of this invention is comprised by the non-insulating converter. It is the figure which simplified and represented the actual winding structure of the transformer represented by the converter vector diagram of FIG. In the rectifier circuit which concerns on the 1st Embodiment of this invention, it is a figure which shows the change of the distortion factor of an input current when changing the phase difference of a primary side phase voltage and a secondary side phase voltage. It is a figure which shows the voltage value of the secondary side phase voltage, secondary voltage, and auxiliary winding voltage when the curve shown in FIG. 4 is obtained. It is a figure which shows the capacity | capacitance of the transformer of a transformer when changing the phase difference (theta) of a primary side phase voltage and a secondary side phase voltage in the rectifier circuit which concerns on the 1st Embodiment of this invention. In the rectifier circuit according to the second embodiment of the present invention, the distortion rate (%) of the input current from the AC power source to the rectifier circuit when the phase difference θ between the primary side phase voltage and the secondary side phase voltage is changed. It is a figure which shows the change of (). It is a figure which shows the voltage value of the secondary side phase voltage when the curve shown in FIG. 7 is obtained. In the rectifier circuit according to the second embodiment of the present invention, the phase difference and the secondary side phase voltage when the distortion rate is suppressed to about 14% or less while maintaining the capacity of the transformer of the transformer at about 43% or less. It is a figure which shows the relationship. In the rectifier circuit which concerns on the 2nd Embodiment of this invention, it is a figure which shows the change of the power capacity of the transformer of a transformer when the phase difference (theta) of a primary side phase voltage and a secondary side phase voltage is changed. . It is a figure which shows the voltage value of the secondary side phase voltage when the curve shown in FIG. 10 is obtained. It is a figure which shows an example of a structure of the conventional rectifier circuit. It is a figure which shows an example of a structure of the conventional rectifier circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st 3 phase full wave rectifier 2 2nd 3 phase full wave rectifier 3 Converter 4 AC power supply

Claims (3)

A first three-phase full-wave rectifier to which three-phase AC power is input; a non-insulated transformer that receives the three-phase AC power and transforms and outputs the three-phase AC power; and And a second three-phase full-wave rectifier to which an output is input, and a rectifier circuit that obtains DC power obtained by combining the outputs of the first three-phase full-wave rectifier and the second three-phase full-wave rectifier. ,
The non-insulating transformer advances the phase of each phase of the three-phase AC power in the range of about 40 ° to about 80 °, and outputs the phase voltage of the three-phase AC power in the range of about 85V to about 95V. A rectifier circuit. A first three-phase full-wave rectifier to which three-phase AC power is input; an insulation transformer that receives the three-phase AC power and transforms and outputs the three-phase AC power; and an output of the insulation transformer. A rectifier circuit for obtaining DC power obtained by synthesizing outputs of the first three-phase full-wave rectifier and the second three-phase full-wave rectifier.
The isolation transformer advances the phase of each phase of the three-phase AC power in a range of about 10 ° to about 50 °, and outputs a phase voltage of the three-phase AC power in a range of about 115V to about 130V. Rectifier circuit.   An air conditioner comprising the rectifier circuit according to claim 1 or 2.

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