JP3256589B2 - Rectifier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rectifier for converting an alternating current into a direct current, reducing a harmonic component of an input current, and improving a power factor.

[0002]

FIG. 13 shows, for example, Japanese Patent Publication No. Sho 62-45794.
FIG. 1 is a circuit showing a conventional rectifier shown in Japanese Patent Application Laid-Open Publication No. H10-209, in which 1 is a rectifier diode, 2 is a smoothing capacitor,
Reference numeral 3 denotes a smoothing reactor as an inductive element, and these constitute a voltage doubler rectifier circuit.

Further, 4 is a load, 5 is a single-phase AC power supply, 6 is a diode for preventing discharge of the smoothing capacitor 2, 7 is a transistor, 8 is a current detector as current detecting means for detecting an input current, and 9 is hysteresis. Reference numeral 10 denotes a comparison circuit serving as comparison means, and reference numeral 10 denotes a driving circuit serving as driving means for the transistor 7.

FIG. 14 is a timing chart showing the relationship between the input power supply voltage and the input current of the rectifier shown in FIG. a is a sinusoidal reference voltage upper limit voltage (reference voltage + hysteresis voltage), b is a sinusoidal reference voltage lower limit voltage (reference voltage-hysteresis voltage), c is an input current, d is a power supply voltage, and e is driving of the transistor 7. Signal.

Next, the operation will be described. In the half-wave period of the single-phase AC power supply 5, one smoothing capacitor 2 is charged via the smoothing reactor 3 by the operation of the one rectifying diode 1, and the other rectifying diode 1 is charged in the next half-wave period.
, The other smoothing capacitor 2 is charged via the smoothing reactor 3.

Since the two smoothing capacitors 2 are connected in series with each other, a DC voltage twice the peak of the power supply voltage charged in one smoothing capacitor 2 is applied to the load 4. Become.

In this circuit, since the smoothing capacitor 2 is not completely discharged, a DC voltage, that is, a residual voltage remains, and a charging current flows only during a period when the power supply voltage is higher than the residual voltage, that is, a period near a peak portion of the power supply voltage. .

Therefore, during a period during which the charging current of the smoothing capacitor 2 does not flow, in other words, during a period when the power supply voltage becomes low, a current is caused to flow by short-circuiting the power supply via the smoothing reactor 3 to reduce a harmonic component of the input current. Reduce and improve power factor.

This power supply short circuit includes a smoothing reactor 3,
It comprises a rectifier diode 1, a transistor 7, and a current detector 8. The transistor 7, the smoothing reactor 3, the rectifying diode 1, the discharge preventing diode 6, and the smoothing capacitor 2 are each provided two by two. Hereinafter, the one located on the upper side of the circuit diagram is referred to as the + side, and the one located on the lower side. On the negative side.

In FIG. 14, a short circuit on the + side works during the period of electrical angle 0 to π, and a short circuit on the − side works between electrical angles π to 2π. The drive signal e is a drive signal for the transistor 7, but since the drive circuit for the transistor 7 on the positive side and the drive circuit for the transistor 7 on the negative side are configured relatively to each other, the two transistors 7 are controlled by a single signal. Controlling.

That is, the period during which the drive signal e is on the + side is a signal for turning on the transistor 7 on the + side, and the period on the-side is a signal for turning on the transistor 7 on the-side. This signal is exactly the same as the output signal of the comparison circuit 9.

In the period of 0 to π, the forward voltage is applied to the transistor 7 on the positive side, so that the electrical angle is 0 °.
The more positive side transistor 7 is turned on. Then, when the input current c reaches the reference voltage upper limit a, the output of the comparison circuit 9 drops to −V _ss , and the transistor 7 on the + side turns off. When the input current c attenuates to the reference voltage lower limit voltage b, the transistor 7 on the plus side turns on again.

In this manner, the on / off operation is repeated. When the voltage approaches the vicinity of π / 2, the charging current of the + side capacitor 2 rapidly increases. It grows significantly. Beyond the point of π / 2,
The charging current of the + side capacitor 2 is attenuated, and the + side transistor 7 starts ON / OFF oscillation again.

During the period of 0 to π, an on signal of the negative transistor 7 is also supplied. At this time, since no forward voltage is applied to the negative transistor 7, it cannot be turned on. Absent. In exactly the same manner as described above, the negative side transistor 7 operates during the period of the electrical angle π to 2π. The conduction current approaches a sine wave like the waveform of the input current c, and the power factor with the waveform of the power supply voltage d is significantly improved.

[0015]

Since the conventional rectifier is constructed as described above, when the power supply voltage is around 0 V, it is composed of the smoothing reactor 3, the rectifier diode 1, the transistor 7, and the current detector 8. The current hardly flows in the power supply short circuit, so that the input current c is distorted around the power supply voltage of 0 V, which limits the effect of reducing the harmonic component of the input current c, and the input power factor also has a limit. There was a point.

The first aspect of the present invention has been made in order to solve the above-mentioned problems. The input current approaches a sine wave near the power supply voltage of 0 V, thereby reducing a harmonic component of the input current. It is an object of the present invention to provide a rectifier capable of improving a power factor, further preventing deterioration of a power use environment, and preventing a harmonic failure.

Another object of the present invention is to provide a rectifier capable of reducing a harmonic component of an input current in accordance with the magnitude of a load and improving a power factor.

A third object of the present invention is to provide a rectifier capable of improving power conversion efficiency by using an integrated reverse PN junction rectifier as a synchronous rectifier by using an insulated gate field effect transistor.

A fourth object of the present invention is to provide a rectifier capable of functioning as a synchronous rectifier during all periods in which an integrated reverse PN junction rectifier of an insulated gate field effect transistor conducts.

[0020]

The rectifier according to the present invention is connected to a single-phase AC power supply via an inductive element.
And one end is connected to the opposite polarity, and the other end is connected in series.
Connected to a pair of smoothing capacitors
Rectifier diode and the rectifier diode connected in parallel.
Switch means and the input current from the single-phase AC power supply.
Output current detecting means and the current detected by the current detecting means.
Compare the input current with the sinusoidal reference voltage to
Comparator that outputs the on / off timing signal of the switch
Stage and voltage polarity discrimination to determine the voltage polarity of the single-phase AC power supply
Means, and the voltage polarity determined by the pressure polarity determining means.
The above switch based on the timing signal from the comparing means
Driving means for driving the means on and off .

According to a second aspect of the present invention, there is provided a rectifier, comprising:
Power supply via an inductive element and one end
And a pair of smoothing capacitors in series between the other end.
A rectifier diode that forms a voltage doubler rectifier circuit by connecting capacitors
Over de and, parallel to the rectifier diode connected switch means
And a current detection for detecting an input current from the single-phase AC power supply.
Output means and a positive voltage according to the magnitude of the load of the voltage doubler rectifier.
Reference voltage adjusting means for adjusting the level of a sinusoidal reference voltage
And the input current detected by the current detecting means and the sine
The switch means is turned on,
Comparison means for outputting an OFF timing signal and single-phase AC
Voltage polarity determining means for determining the voltage polarity of the power supply;
From the voltage polarity determined by the gender determination means and the comparison means
The above switch means is turned on based on the timing signal of
And a driving means for driving off .

In a rectifier according to a third aspect of the present invention, the switch means is an insulated gate field effect transistor having a first electrode, a second electrode and a gate electrode, and a rectifier diode is provided between the first electrode and the second electrode. As a reverse PN junction rectifier connected in a desired rectification direction, the voltage of the single-phase AC power supply is higher than the voltage of the smoothing capacitor connected to the switch means provided in the voltage doubler rectifier circuit. During the period, the driving means drives the gate signal of the gate electrode so as to keep the gate signal on.

In a rectifier according to a fourth aspect of the present invention, the two switch means are insulated gate field effect transistors having a first electrode, a second electrode and a gate electrode, respectively, and two rectifier diodes are provided for each of the switch means. First
As an integrated reverse PN junction rectifying element parasitic between the electrodes and the second electrode and connected in a desired rectifying direction, the driving means turns on and off the gate signals of the two switch means so as to reverse each other. It is something to do.

[0024]

The rectifier according to the first aspect of the present invention is a conventional rectifier in a power supply short circuit constituted by a smoothing reactor, a rectifier diode, a transistor, and a current detector. ,
By forming a closed circuit of an inductive element and a single-phase AC power supply and a smoothing capacitor provided in the voltage doubler rectifier circuit by switch means provided in parallel with the rectifier diode,
Due to the charging voltage of the smoothing capacitor, the input current can flow even when the power supply voltage is near 0 V, and the power supply voltage becomes zero.
The input current is approximated to a sine wave near V to reduce a harmonic component of the input current and improve the power factor.

In the rectifier according to the second aspect of the invention, the reference voltage adjusting means adjusts the level of the sinusoidal reference voltage in accordance with the magnitude of the load, thereby optimally adjusting the input current in accordance with the change in the load. Reduces wave components and improves power factor.

According to a third aspect of the present invention, there is provided a rectifier, comprising a parasitic diode of an insulated gate field effect transistor, that is, an integrated reverse PN parasitic between a first electrode and a second electrode.
By operating the junction rectifier as a synchronous rectifier, power conversion efficiency is improved.

The rectifier according to the fourth aspect of the present invention turns on and off the gate signals of the two switch means so as to invert each other, so that the integrated reverse PN junction rectifier is turned on and off as a synchronous rectifier in all periods. Let it work.

[0028]

[Embodiment 1] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In FIG. 1, reference numerals 1 to 5 and 8 to 10 are the same as or correspond to the components of the conventional rectifying device shown in FIG. Reference numeral 11 denotes a transistor (switch means) such as an insulated gate bipolar transistor or a junction type transistor as switch means connected in parallel with each rectifier diode 1;
Is a smoothing capacitor placed in parallel with the load 4, and 13 is a voltage polarity determination circuit of the power supply voltage.

FIG. 2 shows the relationship between the input power supply voltage and the input current of the rectifier of FIG. a is a sinusoidal reference voltage upper limit voltage (reference voltage + hysteresis voltage),
b is a sinusoidal reference voltage lower limit voltage (reference voltage-hysteresis voltage), c is input current, d is power supply voltage, e and f
Is a drive signal for each transistor 11.

Next, the operation will be described. The rectification method is exactly the same as that of the above-mentioned conventional rectification device, and will not be described. First, a comparison value (comparison means) 9 compares a detection value of the input current of the current detector (current detection means) 8 with a sine wave reference voltage.

The comparison circuit 9 has a hysteresis, and has a sine wave reference voltage upper limit voltage (reference voltage + hysteresis voltage) and a sine wave reference voltage lower limit voltage (reference voltage−
(Hysteresis voltage).

During the period of the electrical angle 0 to π, the closed circuit (short circuit) on the negative side operates, and during the period of the electrical angle π to 2π, the closed circuit (short circuit) on the positive side operates. These are selected by the voltage polarity determination circuit 13. Electric angle 0 ° in the period of electric angle 0 to π
The more negative transistor 11 turns on.

When the input current c reaches the reference voltage upper limit value a, the output of the comparison circuit 9 drops to -V _ss , as in FIG. 14 of the conventional example, and the output of the comparison circuit 9 changes to the drive circuit 1 of the transistor 11.
0 is input to turn off the negative side transistor 11. When the input current c attenuates to the reference voltage lower limit voltage b, the negative transistor turns on again.

In this manner, on and off are repeated, but when approaching the vicinity of π / 2, the rectifying diode 1 on the + side
Is conducted, and the charging current of the + side capacitor 2 rapidly increases, so that the off period of the − side transistor 11 is greatly extended.

When the value exceeds π / 2, the charging current of the + side capacitor 2 is attenuated, and the − side transistor 11 starts ON / OFF oscillation again. In exactly the same manner as described above, the + -side transistor operates during the period of the electrical angle π to 2π.

As described above, during the period when the charging current of each smoothing capacitor 2 does not flow, in other words, during the period when the power supply voltage is low, the smoothing capacitor 2, the smoothing reactor 3, the AC power supply 5, the current detector 8, and the transistor 11 Is formed.

This closed circuit is a period in which the charging current of the smoothing capacitor 2 does not flow, similarly to the power supply short circuit constituted by the smoothing reactor 3, the rectifying diode 1, the transistor 7, and the current detector 8 of the conventional rectifier. In addition, it functions to flow an input current from a power supply.

That is, in the conventional rectifier, the input current i _in from the power supply voltage of 0 V is i _in = (V _in / ωL)
It changes as given by (1-cosωt). However, V _in the peak voltage of the single-phase AC power source 5, ω is the angular frequency, L is the reactance of the power supply short-circuit. But,
In the closed circuit of this embodiment, the input current i _in from the power supply voltage of 0 V is i _in = (V _in / ωL _c ) (1−cosωt)
+ ( _Vc / _Lc ) t. However, V _c is the charging voltage of the smoothing capacitor 2, L _c is the reactance value of the smoothing reactor, t is the time.

FIG. 3 shows an example of the waveform of the input current i _{in when} the power supply voltage is around 0 V, that is, when the electrical angle is 0 to π / 10. Similarly, a and b in the figure denote a sinusoidal reference voltage upper limit voltage (reference voltage + hysteresis voltage) and a sinusoidal reference voltage lower limit voltage (reference voltage-hysteresis voltage), respectively.

Further, c is the input current of the conventional example, c ₁ is the input current waveform of this embodiment, g is the drive signal of the transistor 11 of this embodiment, and h is the drive signal of the transistor 7 of the conventional example.

The input current of the prior art is short-circuited through the single-phase AC power supply 5 via each smoothing reactor 3, and the current flows. Therefore, it is difficult for the power supply voltage to flow in the vicinity of 0V, and the input current depends on the sinusoidal reference voltage. Cannot be approximated to a sine wave.

On the other hand, since the input current of this embodiment flows by short-circuiting the sum of the single-phase AC power supply 5 and the charging voltage of the smoothing capacitor 2 via the smoothing reactor 3, the power supply voltage is close to 0V. But, current proportional to the on time of the charging voltage and the transistor 11 of the smoothing capacitor 2 min V _c t / L
However, since more current can flow than in the conventional example, the input current can be approximated to a sine wave in accordance with the sine wave reference voltage as shown in the input voltage waveform of FIG.

Although FIG. 2 shows a case where the transistor 11 on one side operates during the period of electrical angle 0 to π and the transistor 11 on the plus side operates during the period of electrical angle π to 2π,
As shown in FIG. 4, the drive signals i and j may be alternately turned on and off.

Although FIGS. 2, 3 and 4 show the case where the hysteresis voltage changes, as shown in FIG.
The hysteresis voltage may be fixed. In FIG. 5, a is a sine wave reference voltage upper limit voltage (reference voltage + hysteresis voltage), b is a sine wave reference voltage lower limit voltage (reference voltage−hysteresis voltage), c is a conventional input current waveform, and c ₂ is In the input current waveform of the embodiment, k is a drive signal of the transistor 11 of this embodiment, l is a drive signal of the transistor 7 of the conventional example, and m is a power supply voltage.

Embodiment 2 FIG. In the above embodiment, the reference voltage is fixed. However, the reference voltage may be adjusted according to the magnitude of the load. The components can be reduced and the power factor can be improved.

FIG. 6 is a circuit diagram showing this embodiment.
And 8 to 13 are the same as or correspond to the components of the rectifying device in the embodiment of FIG. 1, and the duplicate description thereof will be omitted here. Reference numeral 14 denotes a reference voltage adjustment circuit (reference voltage adjustment means) that adjusts a reference voltage according to the size of the load. Reference numeral 15 denotes a reference voltage source. Reference numeral 16 denotes a resistor for detecting a voltage applied to the load.

An error amplifier 17 detects an error between the reference voltage source 15 and the voltage applied to the load, and a multiplier 18 outputs a reference voltage from the output of the error amplifier 17 and the power supply voltage waveform.

The operation of this embodiment is almost the same as the operation of the embodiment shown in FIG. 2 or FIG. 4, and a duplicate description of the same operation will be omitted. A reference voltage adjusting circuit 14 for adjusting the reference voltage according to the magnitude of the load compares the voltage of a preset reference voltage source 15 with the output voltage divided by the two resistors 16 and compares the error with an error amplifier. Amplify at 17.

As the load increases, the output voltage decreases, so that the output of the error amplifier 17 increases.
When the load is small, the output of the error amplifier 17 is also small. The output of the error amplifier 17 is multiplied by the power supply voltage waveform by the multiplier 18 to produce a reference voltage according to the magnitude of the load.

As described above, since the sinusoidal reference voltage is changed according to the magnitude of the load, the harmonic component of the input current can be optimally reduced according to the load fluctuation, and the power factor can be improved.

Embodiment 3 FIG. In the embodiment of FIG. 6, the magnitude of the load is determined by the voltage applied to the load,
That is, although the case where the reference voltage is adjusted by detecting the output voltage has been described, the reference voltage may be adjusted by detecting the magnitude of the load by the load current.

FIG. 7 is a circuit diagram showing an embodiment in this case.
1 to 5, 8 to 14 and 17, 18 are the same as or correspond to the components of the embodiment of FIG. 6, and the duplicated description is omitted here. Reference numeral 19 denotes a current detector for detecting a load current. The reference voltage adjustment circuit 14 that adjusts the reference voltage according to the magnitude of the load amplifies the detection value of the current detector 19 that detects the load current by the error amplifier 17.

Here, when the load increases, the load current increases, so that the output of the error amplifier 17 increases. Conversely, when the load is small, the output of the error amplifier 17 decreases because the load current is small. The output of the error amplifier 17 is multiplied by the power supply voltage waveform by the multiplier 18 to generate a reference voltage according to the magnitude of the load, and input to the comparison circuit 9.

Embodiment 4 FIG. In each of the embodiments shown in FIGS. 1, 6 and 7, a sine-wave reference voltage upper limit voltage (reference voltage + hysteresis voltage) and a sine-wave reference voltage lower limit voltage (reference voltage) using a comparison circuit 9 with hysteresis. (Hysteresis voltage), but two sinusoidal reference voltages may be separately generated.

FIG. 8 is a circuit diagram showing an embodiment in this case.
Reference numerals 1 to 5, 8 to 10 and 13 are the same as or correspond to the components of the above-described embodiments, and the description thereof will not be repeated. 20a and 20b are comparison circuits,
1 is an amplifier.

According to this, the detected value of the input current by the current detector 8 and the sine-wave reference voltage lower limit voltage are compared with the comparison circuit 20a.
To generate the off signal of the transistor 11, and to compare the detected value of the input current with the current detector 8 and the sine-wave reference voltage upper limit voltage obtained by amplifying the power supply voltage with the amplifier 21.
Compared with 0b, an ON signal of the transistor 11 is generated.
Other operations are the same as those in the embodiment of FIG.

Embodiment 5 FIG. Further, in each of the embodiments shown in FIGS. 1, 6, 7 and 8, the junction type transistor or the insulated gate bipolar transistor is used as the transistor 11 as the switch means. A transistor (switch means) may be used. Further, a parasitic diode of an insulated gate field effect transistor, that is, an integrated reverse PN junction rectifier may be used as the rectifier diode 1.

FIG. 9 shows an embodiment in this case, and the same or corresponding parts as those shown in FIG. 6 are denoted by the same reference numerals, and redundant description thereof will be omitted. Reference numeral 22 denotes an insulated gate field effect transistor as a switching means having a first electrode 23, a second electrode 24, and a gate electrode 25, which is integrated as a rectifying diode parasitic between the first electrode 23 and the second electrode 24. The reverse PN junction rectifier 1 is connected in a desired rectification direction.

Reference numeral 26 denotes a diode bridge for full-wave rectification of the power supply voltage, and 27 denotes a positive-side smoothing capacitor 2.
, A comparator for comparing the voltage of the + smoothing capacitor 2 with the power supply voltage, 29 a resistor for detecting the voltage of the − smoothing capacitor 2, A comparator 30 compares the voltage of the negative smoothing capacitor 2 with the power supply voltage.

Next, the operation will be described. FIG. 10 is a characteristic diagram showing characteristics of the integrated reverse PN junction rectifier 1 parasitic on the insulated gate field effect transistor 22. The horizontal axis shows the forward voltage, and the vertical axis shows the current flowing through the rectifier,
n indicates the characteristics of the conventional rectifying diode, and o indicates the characteristics of the integrated reverse PN junction rectifying element parasitic on the insulated gate field effect transistor 22.

When the gate electrode 25 is turned on while a current is flowing through the integrated reverse PN junction rectifying element, the gate electrode 25 functions as a synchronous rectifier. When the same current flows, the forward voltage is reduced, so that the loss is reduced. In particular, as shown in FIG. 11, during the period when the power supply voltage d is higher than the capacitor voltage detected by the resistor 27 or 29, the integration reverse PN
It works effectively because a large current flows through the junction rectifier.

FIG. 11 shows the same or corresponding waveforms as those in FIG. 2 showing the relationship between the input power supply voltage and the input current of the rectifier of the embodiment of FIG. Voltage.

When the power supply voltage d becomes higher than the capacitor voltage p on the positive side, the gate electrode 25 of the insulated gate field effect transistor 22 is turned on as shown in FIG. 11B to operate as a synchronous rectifier.

Similarly, when the absolute value of the power supply voltage becomes higher in the negative direction than the output voltage of the diode bridge 26, the insulated gate electric field The gate electrode 25 of the effect transistor 22 is turned on as shown in FIG. 11C to function as a synchronous rectifier. Other operations are the same as in the first embodiment.

Embodiment 6 FIG. Further, in the embodiment of FIG. 9, the case where the gate electrode 25 of the insulated gate field effect transistor 22 is turned on by operating as a synchronous rectifier only when the power supply voltage becomes higher than the capacitor voltage is shown. The means may be driven so that the gate signal is turned on and off in a reverse manner, so that the gate signal functions as a synchronous rectifier during all periods in which the integrated reverse PN junction rectifying element of the insulated gate field effect transistor conducts.

FIG. 12 shows an embodiment in this case. In the embodiment of FIG. 6, the transistor 11 and the rectifier diode 1 as the switch means are formed by an insulated gate type having a first electrode 23, a second electrode 24 and a gate electrode 25. It is replaced with a field effect transistor 22.

According to this, each of the insulated gate field effect transistors 22 is driven such that the on / off of the gate signal is inverted with respect to each other as shown in FIGS.
In all the periods when the integrated reverse PN junction rectifying device 1 of the insulated gate field effect transistor 22 conducts,
The power conversion loss can be reduced by operating as a synchronous rectifier having the current-voltage characteristics shown in FIG.

[0068]

As described above, according to the first aspect of the present invention, the switch means connected in parallel to the rectifier diode constituting the voltage doubler rectifier circuit, and the current detection for detecting the input current from the single-phase AC power supply. Comparing means for comparing the input current detected by the means with the sine-wave reference voltage of the single-phase AC power supply to output a timing signal for turning on and off the switch means; and determining the voltage polarity of the single-phase AC power supply Voltage pole
Gender discriminating means, and the driving means includes a voltage polarity discriminating means.
The switching means is turned on and off based on the voltage polarity determined in the above and the timing signal from the comparing means. Therefore, the sum of the AC power supply and the charging voltage of the smoothing capacitor is supplied to the switching means via the smoothing reactor. A current can flow by short-circuiting, so that the power supply voltage becomes 0 V
In the vicinity, the input current according to the sine-wave reference voltage can flow, and the input power factor can be improved, and the harmonic component of the input current can be reduced to prevent the power usage environment from deteriorating and prevent harmonic interference. There is an effect that something can be obtained.

According to the invention of claim 2, switch means connected in parallel to the rectifier diode constituting the voltage doubler rectifier circuit, current detection means for detecting an input current from the single-phase AC power supply, and the voltage doubler rectifier Reference voltage adjusting means for adjusting the level of the sinusoidal reference voltage of the single-phase AC power supply according to the magnitude of the circuit load, and determining the voltage polarity of the single-phase AC power supply.
Voltage polarity determining means, and
Separate voltage polarity and timing signal from comparison means
Drive means for driving the switch means on and off , and causing the comparison means to compare the input current detected by the current detection means with the sine-wave reference voltage. Since the on / off timing signal is configured to be output, the input power factor can be optimally improved by the reference voltage adjusting means even when the load changes.
There is an effect that a harmonic component of the input current can be optimally reduced and a DC output voltage can be maintained substantially constant.

According to the third aspect of the present invention, the switch means is an insulated gate field effect transistor having a first electrode, a second electrode and a gate electrode, and a rectifier diode is provided between the first electrode and the second electrode. Then, as an integrated reverse PN junction rectifier connected in a desired rectification direction, during a period in which the voltage of the single-phase AC power supply is higher than the voltage of the smoothing capacitor connected to the switch means provided in the voltage doubler rectifier circuit. Since the driving means drives the gate signal of the gate electrode so as to keep the gate signal in the ON state, the power conversion efficiency can be improved by using the integrated reverse PN junction rectifier as a synchronous rectifier. Has the effect.

According to the fourth aspect of the present invention, the two switch means are insulated gate field effect transistors each having a first electrode, a second electrode, and a gate electrode, and two rectifier diodes are the first of the switch means. Electrode and second
As an integrated reverse PN junction rectifying element which is parasitic between the electrodes and connected in a desired rectifying direction, the two switching means are driven so that the gate signals of the two switching means are turned on and off by the driving means so as to be mutually inverted. So, the accumulation reverse direction P
There is an effect that a synchronous rectification operation can be performed during all periods in which the N-junction rectifying element is conducted, so that a power conversion loss can be reduced.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a rectifier according to an embodiment of the present invention.

FIG. 2 is a timing chart showing signals of respective parts of the circuit of FIG.

FIG. 3 is a timing chart showing an enlarged signal waveform of the signal shown in FIG. 2 near a power supply voltage of zero.

FIG. 4 is a timing chart showing signals of respective parts of a circuit according to another embodiment of the present invention.

FIG. 5 is a timing chart showing an enlarged signal waveform of each section of a circuit according to another embodiment of the present invention.

FIG. 6 is a circuit diagram showing a rectifier according to an embodiment of the present invention.

FIG. 7 is a circuit diagram showing a rectifier according to another embodiment of the present invention.

FIG. 8 is a circuit diagram showing a rectifier according to another embodiment of the present invention.

FIG. 9 is a circuit diagram showing a rectifier according to an embodiment of the present invention.

10 is a voltage-current characteristic diagram showing a current characteristic with respect to a forward voltage of an integrated reverse PN junction rectifier of the insulated gate field effect transistor in FIG.

FIG. 11 is a timing chart showing signals of respective parts of the circuit of FIG. 9;

FIG. 12 is a circuit diagram showing a rectifier according to an embodiment of the present invention.

FIG. 13 is a circuit diagram showing a conventional rectifier.

FIG. 14 is a timing chart showing signals of respective parts of the circuit of FIG. 13;

[Explanation of symbols]

REFERENCE SIGNS LIST 1 rectifier diode 2 smoothing capacitor 3 smoothing reactor (inductive element) 4 load 5 single-phase AC power supply 8 current detector (current detecting means) 9 comparison circuit (comparing means) 10 driving circuit (driving means) 11 transistor (switching means) 14 Reference Voltage Adjustment Circuit (Reference Voltage Adjusting Means) 22 Insulated Gate Field Effect Transistor (Switching Means) 23 First Electrode 24 Second Electrode 25 Gate Electrode

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-138063 (JP, A) JP-A-63-253873 (JP, A) JP-A-4-26379 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H02M 7/10 H02M 1/12 H02M 7/21

Claims (4)

(57) [Claims] 1. A voltage doubler rectifier circuit comprising a single-phase AC power supply connected via an inductive element, one end of which is connected to the opposite polarity, and a pair of smoothing capacitors connected in series between the other ends. rectifier diode and a switch means connected in parallel to the rectifier diode, a current detecting means for detecting an input current from the single-phase AC power source, input current detected by said current detecting means and the sinusoidal reference voltage Comparing means for outputting a timing signal for turning on and off the switch means, and determining the voltage polarity of the single-phase AC power supply
Voltage polarity determining means, and
A rectifier comprising: driving means for turning on and off the switch means based on the determined voltage polarity and a timing signal from the comparison means. 2. A voltage doubler rectifier circuit is connected to a single-phase AC power supply via an inductive element, one end of which is connected to the opposite polarity, and a pair of smoothing capacitors connected in series between the other ends. Rectifier diode, switch means connected in parallel with the rectifier diode, current detection means for detecting an input current from the single-phase AC power supply, and a sine wave-like reference according to the magnitude of the load of the voltage doubler rectifier circuit. Reference voltage adjusting means for adjusting a voltage level; comparing means for comparing the input current detected by the current detecting means with the sine-wave reference voltage to output an on / off timing signal for the switch means; , Determine the voltage polarity of the single-phase AC power supply
Voltage polarity determining means, and
A rectifier comprising: a drive unit for turning on and off the switch unit based on the determined voltage polarity and a timing signal from the comparison unit. 3. The switch means comprises an insulated gate field effect transistor having a first electrode, a second electrode, and a gate electrode, and a rectifier diode is parasitic between the first electrode and the second electrode to provide a desired rectifier. The driving means is constituted by an integrated reverse PN junction rectifying element connected in one direction, wherein the voltage of the single-phase AC power supply is higher than the voltage of the smoothing capacitor connected to the switch means provided in the voltage doubler rectifier circuit. The rectifier according to claim 1 or 2, wherein the rectifier is driven so as to keep a gate signal of the gate electrode in an on state. 4. The switch means comprises an insulated gate field effect transistor having a first electrode, a second electrode and a gate electrode, respectively, and two rectifier diodes comprise a first electrode and a second electrode of each switch means. And a driving circuit that turns on and off the gate signals of the two switch means by driving means so as to be mutually inverted. The rectifier according to claim 1 or 2.