JP3339558B2 - Power converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a power converter for converting an AC voltage generated from an AC power supply into a desired voltage.

[0002]

2. Description of the Related Art A power converter converts an AC voltage generated from an AC power supply into a DC voltage by a rectifier circuit and a smoothing circuit, and converts the DC voltage into a desired AC voltage or DC voltage by a power converter circuit. The obtained AC voltage or DC voltage is applied to a load.

[0003] Among them, a power conversion circuit that converts a DC voltage converted by a rectifier circuit and a smoothing circuit into a desired DC voltage is known as a switching regulator. A conventional power conversion device using a switching regulator is shown in FIG. As shown in FIG. 4, in a conventional power converter using a switching regulator, a rectifier circuit 110 and a smoothing capacitor C11 are provided in a stage preceding the switching regulator 130.

The rectifier circuit 110 has four diodes D11 to D14 constituting the rectifier circuit connected in a bridge, and functions to rectify the AC voltage applied from the AC power supply 140 via the AC input terminals 11a and 11b. I have. This rectifier circuit 110 includes a smoothing capacitor C11.
The smoothing capacitor C11 smoothes the voltage rectified by the rectifier circuit 110.

A switching regulator 130 is connected to both ends of the smoothing capacitor C11. In the switching regulator 130, the voltage smoothed by the smoothing capacitor C11 is converted into a desired DC voltage. Further, the switching regulator 130
Are connected to the load via DC output terminals 13c and 13d, and a desired DC voltage is applied to the load by the switching regulator 130.

The rectifier circuit 110, the smoothing capacitor C11, and the switching regulator 130 are all grounded at one end. In the conventional power converter configured as described above, a sine-wave AC voltage (for example, commercial 60 Hz, 100 V) output from the AC power supply 140 is applied between the AC input terminals 11 a and 11 b of the rectifier circuit 110. .
The rectifier circuit 110 rectifies the applied sine wave AC voltage to form a rectified voltage V having a full-wave rectified waveform as shown in FIG.
in is applied to both ends of the smoothing capacitor C11. Therefore, the smoothing capacitor C11 is charged according to the rectified voltage Vin.

The charge charged in the smoothing capacitor C11 is consumed according to the voltage conversion operation of the switching regulator 130. Therefore, although the voltage across the smoothing capacitor C11 fluctuates, the charge is newly supplied due to the magnitude relationship between the voltage across the smoothing capacitor C11 and the rectified voltage Vin, so that the fluctuation is kept small. Can be

Specifically, the smoothing capacitor C11
Is smaller than the rectified voltage Vin,
A current (charging current) flows from the rectifier circuit 110 to the smoothing capacitor C11, and the smoothing capacitor C11 is charged. At this time, the voltage across the smoothing capacitor C11 increases in accordance with the charging current. Conversely, when the voltage across the smoothing capacitor C11 is higher than the rectified voltage Vin, charging is not performed. At this time, the voltage across the smoothing capacitor C11 decreases according to the voltage conversion operation of the switching regulator 130. as a result,
The smoothing capacitor C11 is constantly maintained in a state of storing a substantially constant charge, and a substantially constant voltage (smoothed voltage Vs) is generated at both ends.

The smoothing voltage V of the smoothing capacitor C11
s is once converted into a high-frequency AC voltage in the switching regulator 130 by the action of the switching regulator 130 and then rectified and smoothed again.
It is converted to a DC voltage having a desired voltage value, and the DC output terminal 1
Output to 3a and 13b. This DC voltage is applied to a load as an output voltage.

[0010]

In the above-described conventional power converter, the smoothing capacitor C1 is supplied from the rectifier circuit 110.
As described above, the inflow of the charging current (input current Iin) into 1 is limited only when the smoothed voltage Vs generated across the smoothing capacitor C11 is smaller than the rectified voltage Vin.

That is, the input current Iin to the smoothing capacitor C11 is generated only in a short time only in the vicinity where the rectified voltage Vin has the maximum value. Therefore, the waveform of the input current Iin has a narrow pulse-like flow angle as shown in FIG. FIG. 6 shows a waveform showing a result (spectral characteristic) of performing a spectrum analysis on the waveform of the input current Iin by using a fast Fourier transform (FFT).

As shown in FIG. 6, it can be seen that the input current Iin contains many high-frequency distortion components other than the component of the fundamental frequency fo of the rectified voltage Vin. As described above, in the conventional power converter, the input current Iin has a waveform including a large amount of high-frequency distortion components with respect to the waveform of the rectified voltage Vin. Therefore, in the conventional power converter, the input power factor decreases, the apparent power increases, the power transmission efficiency decreases, and there is a possibility that other devices connected to the power converter may malfunction. Occurs.

In order to deal with these problems, in a conventional power converter, for example, a switching regulator 1
By using a system in which a step-up converter is provided before the stage 30, the high frequency distortion component is suppressed and the power factor is improved. In this method, the power factor can be made close to 1 and ideally. However, since two converters are provided for the boost converter and the switching regulator, the circuit configuration is complicated, and the price is low. Disadvantageous,
Further, on the switching regulator 130 side, a new problem of lowering the conversion efficiency arises.

An object of the present invention is to provide a power conversion device whose power factor is improved satisfactorily and whose circuit configuration is simple.

[0015]

According to a first aspect of the present invention, there is provided a smoothing capacitor for storing power supplied as pulsating current from a rectifier circuit to a power converter, and a smoothing capacitor.
Of the primary winding and the smoothing capacitor
A current transformer consisting of a secondary winding
Including a primary winding and a switching element,
For smoothing by switching using switching elements
A voltage converter for taking in the electric power stored in the capacitor and converting the electric power to a desired voltage. Soshi
Therefore, the above current transformer converts the power taken into the voltage converter
Accordingly, at the timing when current flows in the discharge path,
Due to the electromagnetic coupling between the primary and secondary windings,
Is configured to be injected.

[0016]

(Operation) According to the first aspect of the present invention, the voltage conversion unit is used for smoothing.
By taking in the power stored in the capacitor and converting it to power of a desired voltage, the power stored in the smoothing capacitor decreases. And by the decrease
When the potential of the smoothing capacitor is smaller than the instantaneous value of the voltage of the pulsating flow from the rectifier circuit, the charging path of the smoothing capacitor pulsating current flows from the rectifier circuit, the power is newly smooth
Will be stored in the capacitor . That is, rectification
Operation power supplied as a pulsating flow from the circuit is stored in the smoothing capacitor <br/> is asynchronous to the operation of converting the power of a desired voltage captures the power voltage conversion unit stored in the smoothing capacitor Done in

On the other hand, when the voltage converter performs an operation of taking in the power stored in the smoothing capacitor and converting the power to a desired voltage, the timing at which the current flows by discharging the smoothing capacitor to the voltage converter is performed. And
Current charging path of the smoothing capacitor by the action of the current transformer
Is injected, and the injected current is supplied to the smoothing capacitor . That is, the power of the current injected into the charging path of the smoothing capacitor by the action of the current transformer is
Operation to be replenished in the smoothing capacitor, the voltage conversion unit Rights
The operation is performed in synchronization with the operation of taking in the electric power stored in the sliding capacitor and converting it to electric power of a desired voltage.

Therefore, the smoothing capacitor is asynchronous with the operation of accumulating the electric power given as the pulsating flow,
The current injected into the charging path is supplemented by the action of the current transformer. Furthermore , since the voltage converter performs voltage conversion by switching, the primary winding of the current transformer is arranged.
In the discharge path of the smoothing capacitor , current flows intermittently from the smoothing capacitor toward the voltage converter. Therefore, the primary winding and the secondary winding of the current transformer are electromagnetically coupled, and on the secondary side of the current transformer, a current corresponding to the current intermittently flowing through the discharge path in which the primary winding is arranged is: The secondary winding is intermittently injected into the charging path in which the secondary winding is arranged, and the injected current is supplied to the smoothing capacitor .

Further, when a current flows intermittently in the discharge path in which the primary winding of the current transformer is arranged by switching of the voltage conversion unit, and the primary winding and the secondary winding of the current transformer are electromagnetically coupled, The input end of the voltage converter for performing voltage conversion is equivalently connected in parallel to the secondary winding of the current transformer. Then, the input impedance of the voltage conversion unit becomes low when the switching element that performs the switching is turned on. That is, Con smoothing the power supplied as a pulsating flow
The apparent impedance seen by the source supplying the capacitor will be reduced. Therefore, the amount of current intermittently injected from the above-mentioned supply source into the charging path in which the secondary winding is arranged increases, so that the power supplied to the smoothing capacitor also increases.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating a circuit configuration of a power conversion device according to the present embodiment. In this embodiment, the request
This corresponds to the invention described in Item 1 . The power converter according to the present embodiment includes a switching regulator 30 shown in FIG.
(Voltage converter) converts the DC voltage smoothed by the smoothing circuit 20 into a DC voltage having a desired voltage value, outputs the DC voltage to the DC output terminals 3c and 3d as an output voltage, and applies the output voltage to a load provided at a subsequent stage. Is what you do.

This power converter is characterized in that a current transformer 20A (current transformer) is provided in a smoothing circuit 20 provided before the switching regulator 30, as compared with the conventional power converter. The current transformer 20A performs an operation of replenishing charges to the smoothing capacitor C1 (power storage unit). That is, as shown in FIG. 1, a commercial AC power supply 40, a rectifier circuit 10, and a smoothing circuit 20 including a current transformer 20A are provided at a stage preceding the switching regulator 30.

The rectifier circuit 10 has four diodes D1 to D4 constituting the rectifier circuit connected in a bridge, and functions to rectify an AC voltage applied from the AC power supply 40 through the AC input terminals 1a and 1b. I have. The rectifying operation of the rectifying circuit 10 is shown in FIG.

The rectifier circuit 10 has connection points 1c, 1d
Is connected to the rectifying circuit 10 by the smoothing capacitor C1 constituting the smoothing circuit 20.
The DC voltage after the rectification is smoothed. A secondary coil L22 (secondary winding) constituting one of the current transformers 20A is provided between one connection point 1c connecting the rectifier circuit 10 and the smoothing circuit 20 and one end of the smoothing capacitor C1. Line) is provided. In this case, the secondary coil L22 and the smoothing capacitor C1 are connected in series to form a charging path.

Further, between the one end of the smoothing capacitor C1 and one connection point 3a connecting the smoothing circuit 20 and the switching regulator 30, a primary coil L21 (primary winding) constituting the other side of the current transformer 20A is provided. Line) is provided. The other connection point 1c connecting the rectifier circuit 10 and the smoothing circuit 20, the other end of the smoothing capacitor C1, and the other connection point 3b connecting the smoothing circuit 20 and the switching regulator 30 are all grounded. .

Here, a specific configuration of the switching regulator 30 which has a main function of converting a smoothed DC voltage into a DC voltage having a desired voltage value in the power converter will be described. Note that the switching regulator 30 of this embodiment is configured by a well-known one-stone forward type converter. The switching regulator 30 includes a transformer 31 as a main part thereof, a switch SW provided on a primary side of the transformer 31, a control circuit 32, an absorber 33, and a rectifier circuit 34 and a smoothing circuit 35 provided on a secondary side. It is constituted by.

The transformer 31 includes a primary coil L31, a secondary coil L32, and a reset coil L33. One end of the primary coil L31 is connected to the connection point 3a, and the other end is connected to the connection point 3 via the switch SW.
b.

The reset coil L33 has one end connected to the connection point 3a and the other end connected to the connection point 3b via the diode D5. At this time, the diode D5 is connected in a direction conducting from the connection point 3b to the connection point 3a. Note that a control circuit 32 that switches the on / off state of the switch SW at high speed is connected to the switch SW described above.

Further, a resistor R2 and a capacitor C2 constituting the absorber 33 are connected in series to both ends of the switch SW. The absorber 33 absorbs a surge generated when the on / off state of the switch SW is switched. On the other hand, the rectifier circuit 34 provided on the secondary side of the transformer 31 includes diodes D6 and D7. The smoothing circuit 35 includes a choke coil L
6, a capacitor C3.

The secondary coil L32 of the transformer 31 has one end connected to the DC output terminal 3c via the diode D6 and the choke coil L6. At this time, the diode D6 is connected in a direction that conducts from one end of the secondary coil L32 of the transformer 31 to the DC output terminal 3c. The other end of the secondary coil L32 of the transformer 31 is connected to the DC output terminal 3d, is connected to the DC output terminal 3c via the diode D7 and the choke coil L6, and is further connected via the capacitor C3. It is connected to the DC output terminal 3c. At this time, the diode D7 is connected in a direction that conducts toward the choke coil L6.

Further, both ends of the capacitor C3 are connected to the aforementioned DC output terminals 3c and 3d. A load to which a desired DC voltage converted by the switching regulator 30 is applied is connected to the DC output terminals 3c and 3d. Next, an operation of outputting a DC voltage to the DC output terminals 3c and 3d by the power converter of the present embodiment having the above configuration will be described.

In the preceding stage of the switching regulator 30, a sine-wave AC voltage (commercial 60 Hz, 100V) generated by the AC power supply 40 is supplied to the rectifier circuit 10 as described above.
Is applied between the AC input terminals 1a and 1b. Rectifier circuit 1
0 rectifies the applied sine-wave AC voltage, and as shown in FIG. 2, converts the rectified voltage Vin having a full-wave rectified waveform to the charging path (the secondary coil L2 of the current transformer 20A).
2. Applied to both ends of the smoothing capacitor C1).

In this charging path, a current flows according to the rectified voltage Vin, and the smoothing capacitor C1 is charged. Also,
The charge charged in the smoothing capacitor C1 is consumed according to a voltage conversion operation of the switching regulator 30 described later. Therefore, although the voltage across the smoothing capacitor C1 fluctuates, the voltage is newly charged according to the magnitude relationship between the voltage across the smoothing capacitor C1 and the rectified voltage Vin, so that the fluctuation is suppressed to a small value.

Specifically, when the voltage across the smoothing capacitor C1 becomes smaller than the rectified voltage Vin, a current (charging current) flows through the charging path and the smoothing capacitor C1
Charged. At this time, the voltage across the smoothing capacitor C1 increases according to the charging current. Conversely, when the voltage across the smoothing capacitor C1 is higher than the rectified voltage Vin, no charging current flows through the charging path. At this time, the voltage across the smoothing capacitor C1 decreases in accordance with the voltage conversion operation of the switching regulator 30.
As a result, the smoothing capacitor C1 is constantly maintained in a state where substantially constant power is stored, and a substantially constant voltage (smoothed voltage Vs) is generated at both ends.

The smoothing voltage Vs generated at both ends of the smoothing capacitor C1 is supplied to the switch SW of the switching regulator 30, the transformer 31, the rectifier circuit 34, and the smoothing circuit 35.
After being converted into a high-frequency AC voltage once by such an action, it is rectified and smoothed again and converted into a DC voltage of a desired voltage.

Hereinafter, the voltage conversion operation of the switching regulator 30 will be described. As described above, the primary coil L3 of the transformer 31 is provided between the connection points 3a and 3b connecting the switching regulator 30 and the smoothing circuit 20.
1 and the switch SW are connected in series. And
The switch SW is turned on / off by the control of the control circuit 32.
The off state can be switched at high speed (about several tens of kHz) (high-frequency switching operation).

Therefore, the primary coil L of the transformer 31
31, a smoothing voltage Vs of the smoothing capacitor C1
Is applied intermittently (on / off) in accordance with the high-frequency switching operation described above. As a result, the transformer 31
On the secondary side, an electromotive force (high-frequency AC voltage) whose direction is switched according to the high-frequency switching operation of the primary-side switch SW is generated at both ends of the secondary coil L32.

When the electromotive force generated at both ends of the secondary coil L32 is turned to the direction in which the diode D6 becomes conductive, the current induced in the secondary coil L32 passes through the choke coil L6 to the capacitor C3. Flow into Therefore, the capacitor C3 is charged. Further, when the electromotive force generated at both ends of the secondary coil L32 becomes a direction in which the diode D6 becomes non-conductive, the choke coil L6, the diode D7, and the capacitor are determined based on the energy stored in the choke coil L6. A current flows through a closed circuit in which C3 is connected in series, and charges the capacitor C3.

In this manner, the capacitor C3 is constantly maintained in a state where it is charged with a substantially constant charge, and a substantially constant voltage is generated at both ends. This voltage is output as an output voltage to the DC output terminals 3c and 3d, and is applied to a load connected to the DC output terminals 3c and 3d. The switching regulator 3 of this embodiment
At 0, the absorber 33 can absorb a surge generated when the switch SW is turned on and off.

In the switching regulator 30 of this embodiment, the diode D formed on the primary side
5, reset coil L33 of transformer 31, primary coil L21 of current transformer 22, smoothing capacitor C1
, The electromotive force of the reset coil L33 of the transformer 31 generated when the switch SW is switched to the off state can be prevented from becoming larger than the smoothing voltage Vs of the smoothing capacitor C1 (overvoltage generation). .

Incidentally, the switching regulator 30
Is provided with the above-described current transformer 20A. The charge replenishment operation of the smoothing capacitor C1 by the current transformer 20A intermittently causes a current to flow through the primary coil L21, thereby inducing a current in the secondary coil L22 and reducing the apparent impedance of the charging path. It is a combination of functions. Then, these two functions are combined to improve the transmission efficiency.

Specifically, the operation of replenishing charges to the smoothing capacitor C1 by the current transformer 20A is performed in synchronization with the voltage conversion operation (high-frequency switching operation of the switch SW) by the switching regulator 30 described above. In the voltage conversion operation by the switching regulator 30, when the smoothed voltage Vs is intermittently applied to the primary coil L31 of the transformer 31, the current transformer 2
0A primary coil L21, transformer 31 primary coil L
The discharge current from the smoothing capacitor C1 flows intermittently in a series circuit (discharge path) formed by the switch 31 and the switch SW.

As a result, the primary coil L21 and the secondary coil L22 of the current transformer 20A are electromagnetically coupled, and on the secondary side of the current transformer 20A, the current in the direction in which the diodes D1 to D4 constituting the rectifier circuit 10 become conductive. But,
In response to the intermittent discharge current flowing through the primary coil L21 due to the high-frequency switching operation of the switch SW,
It is intermittently induced in the secondary coil L22 (induced current).

When the primary coil L21 and the secondary coil L22 of the current transformer 20A are electromagnetically coupled, the switching regulator 30 is connected to the secondary coil L22.
When the switch SW is in the ON state, the impedance of the switching regulator 30 decreases. That is, the apparent impedance seen from the AC power supply 40 side decreases. Therefore, the primary coil L21 of the current transformer 20A
In response to the discharge current intermittently flowing through the secondary coil L22
The induced current flowing through the power supply is increased.

Since the secondary coil L22 forms a charging path together with the smoothing capacitor C1 as described above, a large amount of induced current induced in the secondary coil L22 flows into the smoothing capacitor C1. become. As described above, in the smoothing circuit 20, when the discharge current from the smoothing capacitor C1 flows through the primary coil L21 of the current transformer 20A in response to the high-frequency switching operation of the switch SW, the smoothing capacitor C1 is synchronized with this. Is replenished with a lot of electric charges according to the induced current induced in the secondary coil.

That is, the replenishment of the electric charge according to the induced current to the smoothing capacitor C1 is performed irrespective of whether the smoothed voltage Vs generated at both ends of the smoothing capacitor C1 is smaller than the rectified voltage Vin. As a result, the smoothing capacitor C
1 is smaller than the rectified voltage Vin, and the original charging current (corresponding to the conventional input current Iin).
During the period when flows through the charging path, a large amount of induced current induced in the charging path is superimposed on the charging current and flows into the smoothing capacitor C1. In this case, the sum of the induction current and the charging current becomes the input current Iin.

On the other hand, during the period when the smoothing voltage Vs generated at both ends of the smoothing capacitor C1 is larger than the rectified voltage Vin and the original charging current does not flow through the charging path, there are many inductions induced on the charging path. When the current is equal to the smoothing capacitor C1
Will flow into. In this case, the induced current becomes the input current Iin. When the charge replenishment operation by the current transformer 20A was actually examined, a waveform as shown in FIG. 2 was obtained as the input current Iin of the smoothing capacitor C1.

As shown in FIG. 2, the input current Iin is
It was confirmed that the rectified voltage Vin did not flow into the smoothing capacitor C1 only near the maximum value, but also flowed at other timings. That is, the input current Iin is different from the conventional input current shown in FIG. 5 (corresponding to the input current Iin in FIG. 5) in that the rectified voltage Vin is
Has a widened distribution angle with respect to.

FIG. 3 shows a waveform showing a result (spectral characteristic) of performing a spectrum analysis on the waveform of the input current Iin by using fast Fourier transform (FFT). As shown in FIG. 3, the input current Iin includes the fundamental frequency fo of the rectified voltage Vin.
It can be seen that almost no high frequency components other than the above components are included. That is, this spectral characteristic has a high power factor in which high frequency components are suppressed.

As described above, in the power converter of the present embodiment, the input is promoted by the action of the current transformer 22 while discharging from the smoothing capacitor C1 in accordance with the high-frequency switching operation of the switching regulator 30. It is possible to easily configure a power converter in which the power factor is improved, the apparent power is reduced, and the power transmission efficiency to the power supply is improved.

In the power converter of this embodiment, the magnitude of the induced current induced on the secondary side of the current transformer 20A is determined by the ratio of the number of turns N21 of the primary coil L21 to the number of turns N22 of the secondary coil L22 ( Transformation ratio: N21 / N22)
And is proportional to the magnitude of the discharge current flowing through the primary coil L21. The discharge current flowing through the primary coil L21 depends on the power consumed by the loads connected to the DC output terminals 3c and 3d. The current transformer ratio of the current transformer 22 may be determined according to the resistance value of the load.

In the power converter of this embodiment, a circuit for stabilizing a DC voltage output between the DC output terminals 3c and 3b is not shown or described.
Such an output stabilizing circuit includes, for example, a capacitor C3
Constantly monitors the voltage at both ends of the
This can be realized by a feedback circuit that controls the pulse width (the ratio between the ON period and the OFF period) of the switch SW.

Further, in the power converter of the present embodiment,
The primary coil L21 of the current transformer 20A is provided between one end of the smoothing capacitor C1 and one connection point 3a connecting the smoothing circuit 20 and the switching regulator 30, but the smoothing capacitor C1, the switch SW, the transformer 31 may be provided at any position on the closed circuit formed by the primary coil L31.

In the power converter according to the present embodiment, the current transformer 20A is provided in the smoothing circuit 20 to perform the charge replenishment operation to the smoothing capacitor C1, but the same operation is performed by a current transformer using a Hall element. Can be performed. Furthermore, in the power converter of the present embodiment, the switching regulator 30 is configured by a single-forward converter. However, if a high-frequency suppression (power factor improvement) circuit by the current transformer 20A can be applied, the switching regulator of any configuration. It is also applicable to:

The present invention can also be applied to an inverter that converts a DC voltage to a desired AC voltage by using the high-frequency switching operation of the switch SW.

[0056]

As described above, according to the first aspect of the present invention, when pulsating power is supplied from the rectifier circuit to the smoothing capacitor , the current transformer injects current into the charging path. Since a current corresponding to the power taken into the voltage conversion unit is injected, a power conversion device is provided in which the power factor is satisfactorily improved, the apparent power is reduced, and the power transmission efficiency is improved.

[0057] In addition, current transformer is composed of a primary winding and a secondary winding, furthermore, according to the current flowing through the primary winding when the voltage converting unit performing voltage conversion by switching the secondary windings A lot of current is injected into the charging path where
A power converter capable of efficiently improving the power factor can be simply configured.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a circuit configuration of a power converter.

FIG. 2 is a diagram showing a time waveform of a rectified voltage Vin and an input current Iin.

FIG. 3 is a diagram showing a spectrum waveform of an input current Iin.

FIG. 4 is a diagram showing a circuit configuration of a conventional power converter.

FIG. 5 is a diagram showing a time waveform of a rectified voltage Vin and an input current Iin.

FIG. 6 is a diagram showing a spectrum waveform of an input current Iin.

[Explanation of symbols]

10, 34, 110 Rectifier circuit 20, 35 Smoothing circuit 30, 130 Switching regulator (voltage conversion unit) 40, 140 AC power supply C1, C11 Smoothing capacitor (power storage unit) SW switch 20A Current transformer (current transformer) 31 Transformer 32 Control circuit 33 Absorber

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-292356 (JP, A) JP-A-5-3444731 (JP, A) JP-A-7-15967 (JP, A) (58) Survey Field (Int.Cl. ⁷ , DB name) H02M 3/28 H02M 7/21 H02M 7/48

Claims (1)

(57) [Claims] 1. A smoothing capacitor for accumulating electric power given as a pulsating current from a rectifier circuit, and a primary winding disposed in a discharge path of the smoothing capacitor.
From the secondary winding arranged in the charging path of the smoothing capacitor.
And a primary winding and a switching element arranged in the discharge path.
In addition, switching using the switching element
More captures the power accumulated in the smoothing capacitor, and a voltage converter for converting the power of a desired voltage, the current transformer respond to the power to be taken to the voltage conversion unit
At the same time as the current flows through the discharge path.
The electromagnetic coupling between the primary and secondary windings of the
A power converter characterized by injecting a current into an electric circuit .