JPH06165497A - Power supply device - Google Patents

Abstract

PURPOSE:To improve follow-up to a sine wave of an input current waveform regarding a section, in which the input current waveform cannot follow up the sine wave remarkably, in a power supply device using a chopper circuit. CONSTITUTION:In a power supply device, in which an AC power supply AC is rectified by a full-wave rectifier DB and smoothed by a chopper circuit with an inductor L1, a switching element Q1 and a diode D1, the on section of the switching element Q1 is lengthened in a section, in which an input current waveform cannot follow up a sine wave remarkably. Or the value of the inductor L1 is lowered. Accordingly, the quantity of currents in the forward direction is made larger than that in the negative direction of the switching element Q1 generated by the delay time of the control circuit of the switching element Q1, thus improving follow-up to the sine wave of the input current waveform, then reducing the higher harmonic component of input currents.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device using a chopper circuit, which is used for obtaining a direct current output while making an input current from a commercial power supply have a waveform close to a sine wave with few rest periods. It is what is done.

[0002]

2. Description of the Related Art Conventionally, a DC voltage obtained by rectifying and smoothing an AC voltage of a commercial power source is converted into a high frequency by an inverter or the like,
Devices for supplying electric power to a load (for example, a discharge lamp) are widely used. In this type of device, smoothing the rectified output of the commercial AC voltage is necessary in the case of a discharge lamp load.
By preventing the envelope of the supplied high-frequency current from fluctuating in the commercial AC cycle, the re-ignition phenomenon of the discharge lamp is substantially eliminated, the luminous efficiency of the discharge lamp is improved, and the power consumption of the device is reduced. , To improve the performance by eliminating the flicker of light. However, when the commercial AC voltage is rectified and smoothed, the current flowing from the commercial power source to the smoothing capacitor flows only near the peak value of the commercial AC voltage, and the peak value having a pause period is high every half cycle of the commercial AC voltage. Since it is a current, the input power factor is poor, and it also contains many high-order harmonic current components with respect to the AC fundamental wave, so that harmonic noise is mixed into other equipment that is connected to the same AC distribution system. There was a bad effect of. Therefore, in order to increase the power factor of the input current, reduce the harmonic component, and supply a DC smoothing voltage that is as flat as possible, the following measures have been taken.

FIG. 23 is a circuit diagram of a conventional example. Below,
The circuit configuration of will be described. AC power supply AC is full-wave rectification
It is connected to the AC input terminal of the container DB. Full wave rectifier D
The DC output terminal of B is composed of a power MOSFET.
Itching element Q₁Through inductor L₁Is connected
ing. Switching element Q₁For backflow prevention at both ends of
Diode D₁Capacitor C for smoothing via₁Contact
Has been continued. Smoothing capacitor C₁Negative at both ends of
The load Z is connected. Inductor L₁And switching
Element Q₁And diode D₁Is a step-up chopper circuit
It constitutes the CHP. Full-wave rectification with one end of AC power supply AC
Between the grounded output terminals of the device DB, a half-wave rectifier is connected.
Iodo D₂And resistance R for current limiting₂For smoothing through
Densa C ₂And Zener diode ZD for voltage regulation₁But
It is connected. Capacitor C₂DC voltage obtained in
Is a timer circuit IC₁Power terminal (pin 8) and ground
It is applied between terminals (Pin 1). Timer circuit
IC₁Is a general-purpose timer IC (for example, NEC Corporation)
Trigger terminal consisting of μPC1555) manufactured by the company
(Pin 2) and threshold terminal (Pin 6) and release
A resistor R is attached to the electric terminal (7th pin)._Four, R_FiveAnd capacitor
C_FourA time constant circuit consisting of
It is used as an astable multivibrator.
Capacitor C₂At both ends of the resistor R₃And capacitor C₃
A delay circuit consisting of a series circuit of
Sensor C₃Is input to the frequency control terminal (Pin 5).
Has been. High frequency quadrature obtained at the output terminal (Pin 3)
The square wave signal is a buffer circuit IC₂(For example, NEC Corporation
Switching element via μPD4050)
Child Q₁Is input to the control electrode of. Switching element
Q₁Turns on, inductor L₁Energy stored in
The switching element Q₁When is turned off,
L₁Self-induced electromotive force is generated in the commercial power AC
Capacitor C for superimposing on the full-wave rectified output voltage of
₁It will be charged to.

In the conventional example of FIG. 23, the inductor L₁
Current flowing through the switching element Q ₁Voltage applied to
The waveform of is shown in FIG. Time t₁And switching element Q
₁Turns on, inductor L₁Current gradually increases
Go, time t₂And switching element Q₁Turns off
Then, after that, inductor L₁The energy stored in
It discharges and the electric current decreases gradually. And time
Tick t₃Inductor L ₁When the current of becomes 0,
As shown by the broken line, the switching element Q₁And diode
D₁Stray capacitance C₆, C₇The electric charge stored in
Inductor L₁Current flows in the opposite direction to the full-wave rectifier DB
Stray capacitance C_FiveLC resonance occurs through. For this reason,
Time t₃~ T_FourSwitching element Q₁Is a resonant electric
Pressure is applied, switching element Q₁And full wave rectifier DB
There was a problem that the stress on the. Also,
Time t₃~ T_FourLong current pauses, such as
The input current has many components. That is, the input voltage is a sine wave
In the case of, at time t near the peak value of the input voltage₃~ T_Fourof
The current quiescent period becomes shorter and conversely the input voltage is lower.
Since the current pause period becomes longer in the section, as shown in FIG.
As the input current near the peak value of the input voltage is large,
The problem that the input current decreases in the low voltage range
However, some kind of waveform correction circuit was necessary.

Therefore, as shown in FIG.
Completely eliminate the gap, inductor L ₁The energy of
Before being fully discharged, the switching element Q₁Turn on
Inductor L₁It is possible to apply a current to the
In case of, diode D₁Current is flowing to the
Densa C₁Since a reverse voltage of ₁
Recovery current Ir flows to diode D₁Streak
The size also increases. Also, inductor L₁Current i flows to
Inductor L as we continue₁Stored energy (L₁×
i² / 2) increases and inductor L₁Is saturated, etc.
I have a problem. Therefore, as shown in the circuit of FIG.
And inductor L₁Completely release the energy of
One control is required to eliminate the rest period.

The circuit configuration of FIG. 28 will be described below. The AC power supply AC is connected to the AC input terminal of the full-wave rectifier DB. A small capacity capacitor C ₈ is connected to the DC output terminal of the full-wave rectifier DB. Capacitor C
_An inductor L ₁ is connected to both ends of ₈ via a switching element Q ₁ composed of a power MOSFET.
Ds is a reverse parasitic diode of the switching element Q ₁ . A smoothing capacitor C ₁ is connected to both ends of the switching element Q ₁ via a diode D ₁ for blocking backflow. A load Z is connected to both ends of the smoothing capacitor C ₁ . A resistor R for voltage detection is provided across the load Z.
A series circuit of ₆ and R ₇ is connected. Resistors R ₆ and R ₇
The potential at the connection point is input to the differential amplifier IC ₃ , the voltage corresponding to the difference from the reference potential Vref is amplified, and the voltage is connected to the negative input terminal of the voltage comparator IC ₄ . Differential amplifier IC
_A capacitor C ₁₀ is connected to ₃ as a feedback impedance. The capacitor C ₉ is connected to the positive input terminal of the voltage comparator IC ₄ . A transistor Q ₂ is connected in parallel to both ends of the capacitor C ₉ . The inverting output terminal Q ′ of the flip-flop FF is connected to the base of the transistor Q ₂ . Flip flop F
The output terminal Q of F is connected to the control electrode of the switching element Q ₁ via the resistor R ₁ . Flip flop F
The reset terminal R of F is connected to the output terminal of the voltage comparator IC ₄ , and the set terminal S is connected to the output terminal of the detector IC ₅ . The current flowing through the switching element Q ₁ is converted into a voltage by the resistor R ₈ and input to the detector IC ₅ . A constant current flows through the transistor Q ₃ through the resistor R ₉ , and the same current flows as the transistor Q 3.
Flows to capacitor C ₉ via ₄ .

FIG. 29 shows a time chart of this circuit.
You First, time t₁Then, the detector IC _Five Is the inductor L
₁And switching element Q₁Or diode D₁And flat
Sliding capacitor C₁Through resistance R₈ Current flowing in
Is detected and a high level signal is output.
It As a result, the set terminal S of the flip-flop FF
Signal from the output terminal Q of the high level
The signal also goes low from the inverting output terminal Q '.
Signal is output and switching element Q₁Turn on the transistor
Q₂Turn off. Next, time t₁~ T₂In the period of
Langista Q₂Is turned off and transistor Q₃，
Q_FourWith the current mirror circuit by the control power supply voltage Vcc
Resistance R₉The current determined by the capacitor C₉Charge the
And capacitor C₉The voltage across the
Ku. Resistance R₆ , R₇ The divided potential due to is the reference potential Vre
differential amplifier IC with f₃Is input to the differential amplifier I
C₃Output is constant at a certain level. Its voltage
Capacitor C to level₉When the voltage across both ends of
₂With voltage comparator IC_FourOutputs a high level signal from
And is input to the reset terminal R. Because of this,
Low level signal from the output terminal Q of the flip-flop FF
However, a high level signal is output from the inverting output terminal Q '.
Signal is output and the switching element Q₁Off, tran
Dista Q₂Turns on. Furthermore, time t₂~ T₃Period of
In between, switching element Q₁While the is on
Ducta L₁, Switching element Q₁, Resistance R₈Through
Inductor L due to the flowing current₁Energy stored in
Rugie is the switching element Q₁Emitted when is off
The inductor L₁To diode D₁, Capacitors
C₁, Resistance R₈Current flows to the capacitor C₁Is full
Be charged. In addition, as described above, the capacitor C₁Is charged
Transistor Q while₂Is turned on,
Densa C₉The potential of does not rise. And inductor L
₁When the current due to the energy of
₃(Or t₁), The resistance R₈The current flowing through is zero
After that, the same operation is repeated. Thus, at time t₁
~ T₂Inductor L₁Electricity flowing through
When the flow becomes zero, the switching element Q₁
By controlling the timing when the ON signal of
Inductor L₁It is possible to eliminate the pause section of the current flowing through
Wear. Therefore, the input current wave with relatively few harmonic components
Be in shape.

[0008]

However, according to FIG.
Also in the conventional example, the voltage of the pulsating current waveform obtained by full-wave rectifying the input voltage
As shown in Fig. 30, in the low part (valley part) of
In the section T where the input current waveform cannot noticeably follow the sine wave
x (non-followable section) occurs. That is, the control motion described above
Resistance R₈Detected that the current flowing through the
Then switching element Q₁Until the ON signal is output to
In the meanwhile, a delay time ts actually occurs due to the circuit operation.
U Therefore, as shown in FIG. 31 and FIG.
Kuta L₁Delay time t after the current flowing through
Stray capacitance and inductor as described in Fig. 25 only during s
L₁Resonance current of the switching element Q₁
Switching element Q₁The current of the negative direction
Will flow out. By the way, inductor L₁Charge of
The degree of increase (slope) of the discharge current is Vin during charging.
/ L₁And becomes (Vout-Vin) / L during discharge₁
Becomes Where Vin is the input voltage of the chopper, Vo
ut is the output voltage of the chopper. Output voltage Vout
Is substantially constant, the switching element Q₁Switch
Depending on the value of the input voltage Vin at the time of charging,
Inductor L₁The slope of the current flowing through the
When in is large (the peak of the pulsating current), charge
The slope of time is large and the slope of discharge is small. Also type
When the voltage Vin is small (at the valley of the pulsating flow)
Has a small slope during charging and a large slope during discharging. Shi
Therefore, the delay time ts of the control circuit is generated as described above.
3 and FIG. 3 even if the delay time ts is the same.
As shown in 2, the switching element Q₁Of the current flowing through
Negative current amount J₁Will be different. Figure 31 shows the input power
Inductor L when pressure Vin is small₁Current wave flowing through
Figure 32 shows the inductor when the input voltage Vin is large.
L₁It is a current waveform flowing through. Therefore, switchon
Element Q₁ON section T₁(= T₂-T₁) Is constant
Even if it is controlled so that the actual ON section T ₂Is the input voltage V
It differs when in is small and when it is large. here
Then, as shown in FIG. 31, the switching element Q₁When on
The amount of negative current flowing through (the shaded area J₁) And positive current
Quantity (horizontal line part J₂) Is J₁> J₂When
The input current waveform cannot track the sine wave
The feasible section Tx remarkably occurs. For this reason the input waveform
Will generate harmonic components. As mentioned above, Cho
Constant control of ON section of switching element of upper circuit
With this method, the input current waveform can follow the sine wave remarkably.
There is a missing part. This allows the input current waveform to
Ingredients are generated.

The present invention has been made in view of the above points, and in a power supply device using a chopper circuit,
It is an object of the present invention to improve tracking of an input current waveform to a sine wave at least in a section where the input current waveform cannot significantly follow the sine wave.

[0010]

In order to solve the above-mentioned problems, in the power supply device of the present invention, an AC power supply AC,
Full-wave rectifier DB for full-wave rectifying AC voltage of AC power supply AC
And the rectified output of the full-wave rectifier DB to the switching element Q ₁
Energy is intermittently stored in the inductor L ₁ by intermittently connecting the inductor L _{1 and} the stored energy in the inductor L ₁ is released through the diode D ₁ for blocking the reverse current; and the inductor L ₁
In a power supply device having a control circuit for controlling the switching element Q ₁ to be turned on for a certain period after detecting that the current flowing through is zero, at least based on the pulsating current waveform after full-wave rectification. and characterized in that the addition circuit current amount in the positive direction to control the switching element to Q ₁ oN zone to be larger than the negative direction of the current amount flowing between said switching element Q ₁ is turned on To do. The ON period of the switching element Q ₁ may be controlled stepwise or continuously. Further, the value of the inductor L ₁ may be changed instead of controlling the ON section.

[0011]

As described above, the section in which the input waveform cannot remarkably follow the sine wave is switched from the inductor L ₁ when the switching element Q ₁ controlled so that the ON section of the chopper circuit is constant. In the current flowing to the element Q ₁ , the negative direction current generated by the delay time of the operation of the control circuit becomes larger than the positive direction current, that is, as shown in FIG. 31. I will end up. The operation of the present invention for improving it is shown in FIG.
3 shows.

In FIG. 33, the amount of current in the positive direction (horizontal line portion J ₂ ) is larger than the amount of current in the negative direction (hatched portion J ₁ ) in the ON section (t ₁ -t ₂ ) of the switching element Q ₁ which is constant in the past. At least J ₁ when the number is small (when J ₁ > J ₂ )
<J ₂ + J ₂ 'become as t ₂ ON interval from t _2'
It is improved so that it does not look like FIG. 31. At least in the section where the input current waveform does not follow the sine wave remarkably, if the ON section is expanded as described above, the harmonic component of the input current waveform is reduced.

The same condition can be satisfied by changing the value of the inductor L ₁ instead of extending the ON section of the switching element Q ₁ .

[0014]

1 is a circuit diagram of a first embodiment of the present invention.
In this embodiment, in the conventional example of FIG. 28, a full-wave rectifier D
The positive output terminal of B is connected to the positive electrode of a capacitor C ₉ via a resistor R ₁₀ and a diode D ₃ . Therefore, according to the pulsating flow waveform output from the full-wave rectifier DB,
The charging speed of the capacitor C ₉ changes. Other configurations are similar to those of the conventional example of FIG. In the conventional example of FIG. 28, according to the capacity of the current and the capacitor C ₉ which is determined by the resistor R _9, the slope of the increase in potential across the capacitor C ₉ becomes constant, also becomes constant on the interval switching element Q ₁ Was controlled as. On the other hand, in this embodiment, by connecting the series circuit of the resistor R ₁₀ and the diode D ₃ between the full-wave rectified output and the capacitor C ₉ , as shown in FIG. 1, the charging speed of the capacitor C ₉ can be increased. Is changed based on the pulsating flow waveform after full-wave rectification. That is, as shown in FIG. 2, the current flowing through the capacitor C ₉ changes to the constant current Ia determined by the conventional resistor R ₉ and the pulsating current Ib.
Will be superimposed, and in the portion where the input voltage is close to zero (valley portion of the pulsating flow waveform), the potential across the capacitor C ₉ will be higher than that in the portion where the input voltage is near peak (the pulsating current peak portion). The slope of the increase becomes small, and the ON section of the switching element Q ₁ becomes relatively wide. Where resistance R
By changing the value of _{9 and} the value of the resistor R ₁₀ and changing the ratio of the currents Ia and Ib, switching as shown in FIG. 33 is performed in the section where the input current waveform does not noticeably follow the sine wave. Can be made to follow the sine wave as much as possible to reduce the harmonic components of the input current.

FIG. 3 is a circuit diagram of the second embodiment of the present invention.
It In the conventional example of FIG. 28 described above, the voltage comparator IC_FourNegative of
The reference voltage applied to the input terminal is the output of the chopper circuit.
Force voltage to resistance R₆, R₇Differential amplifier IC
₃Kept constant by giving feedback in
I was there. The output voltage of the chopper is constant and the
Densa C₉Capacity and capacitor C₉Constant current flowing into
Flow-determined capacitor C ₉The slope of the increase in the potential across
Since it is constant, the switching element Q₁On time is
It was constant. In this embodiment, as shown in FIG.
At least J₁> J ₂Then, as shown in FIG. 33,
J₁<J₂+ J₂Switching element Q
₁To extend the ON section of the resistor R₁₁, R₁₂, Tran
Dista Q_Five, Q₆The current mirror circuit and
Anti-R₁₃Are added as shown in FIG. This makes the current
Current Ic flowing through the mirror circuit is full-wave rectified waveform of input voltage
Flows with the same pulsating waveform as the voltage comparator IC_FourNegative input terminal
The reference potential of the differential amplifier IC ₃From the output potential of Ic ×
R₁₃The waveform has a voltage drop corresponding to the voltage drop of. Waveform of each part
Is as shown in Fig. 4, and it is
Switching element Q₁The on-time of the
It will be longer than a minute. Resistance R₇Value, current Ic, resistance R
₁₃Of the differential amplifier IC by changing the value of₃Output potential and Ic
× R₁₃By changing the ratio of the potential dropped by
At least J as shown in Fig. 31₁> J₂Where
As shown in Figure 33, J₁<J₂+ J₂’
The input current waveform cannot follow the sine wave remarkably.
To improve the waveform between and reduce the harmonic components of the input current
You can

FIG. 5 is a circuit diagram of the third embodiment of the present invention. In this embodiment, the rectified output terminals of the full-wave rectifier DB, a series circuit of resistors R _14, R ₁₅ are connected. Resistance R ₁₄ ,
The potential at the connection point of R ₁₅ is input to the detector IC ₆ .
The output of detector IC ₆ is connected to the base of transistor Q ₇ . The transistor Q ₇ is connected in series with the resistor R ₁₇ and is connected in parallel with both ends of the resistor R ₉ . Other configurations are similar to those of the conventional example of FIG.

The operation of this embodiment will be described below.
The pulsating flow waveform output from the full-wave rectifier DB is the resistance R₁₄, R
₁₅Is divided by the detector IC₆Entered in. Detector
IC ₆Then, compare the input voltage with the reference potential, and
In the section higher than the quasi-potential, the transistor Q₇ON to
Give the issue. The reference potential is the potential at which the non-followable section Tx starts
Is set to. Transistor Q at the peak of pulsating flow waveform
₇When an ON signal is input to the resistor R₉ And R₁₇Are connected in parallel
Therefore, the transistor Q₃ , Q_Four Current flowing through
Get Therefore, the capacitor C₉ Charging speed is faster
Transistor Q₇When OFF (at the valley of the pulsating flow)
In comparison, switching element Q₁ ON time becomes short.
Therefore, as shown in FIG.₁ ON
The time is decided. Detector IC₆Fig.
As shown in 31,₁≧ J₂In the area
Dista Q₇OFF, switching element Q₁ When ON
Open the gap and, conversely, as shown in FIG.₁<J₂of
In the area, the transistor Q₇To turn on the switching element
Child Q₁ A tracking effect is produced by shortening the ON time of
You Transistor Q₃ Side resistance R₉ And R₁₇All values of
J in the section₁<J₂Is set so that

FIG. 7 is a circuit diagram of the fourth embodiment of the present invention.
It In this embodiment, in the third embodiment shown in FIG.
Detector IC₆The number of detection levels in
It As the potential of the pulsating current waveform rises, the transistor Q
₇ , Q₈, Q₉,,, Qn are turned on in order, and the resistance R
₁₇, R₁₈, R₁₉,,, Rn in order of resistance R₉Parallel to
Get connected. Conversely, the potential of the pulsating flow waveform decreases
Kuto transistor Qn-Q ₇ On the contrary, it turns off.
As a result, the switching element Q₁ ON time is pulsating waveform
To gradually spread from the mountain part to the valley part
Therefore, the effect of tracking the input current to the input voltage is the same as in the third embodiment.
It can be controlled more finely.

FIG. 8 is a circuit diagram of the fifth embodiment of the present invention.
It Also in this embodiment, it is similar to the third embodiment shown in FIG.
And the resistance R₁₄, R₁₅To detect the pulsating flow waveform by the detector I
C₆Transistor Q₇ ON / O
The signal for FF is output. Tigers at the valley of the pulsating waveform
Register Q₇ When an ON signal is input to the resistor R₇ , R₁₇Is average
The column connection is established, and the potential at point A drops. The potential at point A is
When lowered, the differential amplifier IC as shown in FIG.₃ Output increases
And voltage comparator IC_Four The level of the negative input terminal of
And as a result, the capacitor C₉ Long charging time
And the switching element Q₁ ON time is a transistor
Q₇ It becomes longer than when it is OFF (the peak of the pulsating current).
Detector IC₆J detection output₁≧ J₂Section
And J₁<J ₂Divided into at least 2 sections
J₁≧ J₂Transistor Q in the section₇ Turn on
Switching element Q₁ Lengthening the ON time of₁<
J₂Transistor Q in the section₇ Turn off the switch
Holding element Q₁ Follows by shortening the ON time of
Produce an effect. Resistance R₇ , R₁₇The value of is the third actual value shown in FIG.
Set under the same conditions as in the example.

FIG. 10 is a circuit diagram of a sixth embodiment of the present invention. Also in this embodiment, as in the fifth embodiment, the potential at the point A is changed using the resistors R ₁₇ , R ₁₈ , ..., Rn and the transistors Q ₇ , Q ₈ ,. By doing so, the output of the differential amplifier IC ₃ , that is, the level of the negative input terminal of the voltage comparator IC ₄ is changed, and the ON time of the switching element Q ₁ is changed.
Similar to the fourth embodiment of FIG. 7, increasing the number of detection level of the pulsating waveform, as the potential of the pulsating waveform is reduced, in turn continue to turn ON the transistor Q ₇ Qn, resistor R ₁₇ ~Rn
And the resistor R ₇ are connected in parallel in this order. On the contrary, when the detected potential increases, the transistors Qn to Q ₅ are turned off. As a result, similar to the fourth embodiment shown in FIG. 7, a fine tracking effect can be obtained.

FIG. 11 is a circuit diagram of the seventh embodiment of the present invention. In the present embodiment, at least when the negative direction current amount J ₁ and the positive direction current amount J _{2 of the} switching element Q ₁ are J ₁ > J _{2 as} shown in FIG. 31, as shown in FIG. By increasing the gradient of the flowing current even during the on-time, the control is performed so that the negative current amount J ₁ 'and the positive negative current amount J ₂ ' will be J ₁ '<J ₂ '. It is a thing. As a result, it is possible to improve a section in which the input current waveform cannot follow the sine wave (non-trackable section) and reduce the harmonic component from the input current. In order to perform this control, a series circuit of inductors L ₁ and L ₂ is used in this embodiment, and a switching element Q is provided at both ends of the inductor L _1.
10 are connected in parallel. The switching element Q ₁₀ has
A drive signal is input from the control unit 2. A voltage obtained by dividing the output voltage of the full-wave rectifier DB by the resistors R ₁₄ and R ₁₅ is input to the control unit 2.

The operation of this embodiment will be described below.
Switching element Q₁ Is the inductor of the chopper circuit
L₁ , L₂ When the current flowing in the
Given an ON signal, it operates with a certain ON time
Controlled by. However, inductor L₁ , L₂ Flow
Switching element Q₁ Is o
There is a delay time in the operation of the control unit 1 before turning on.
Due to this delay time, there is a section where the input current waveform cannot be tracked.
It is the same. In order to improve this, as shown in Fig. 32,
Switching element Q from the inductor₁ Negative of current flowing to
Directional current amount J₁Is the current amount J in the positive direction₂ Compared to J₁ <J₂
 Switching element Q_TenLet's turn off
The inductor value to L₁ + L₂ And at least Figure 3
J like 1₁ > J₂ Switching element Q
_TenTo turn on the inductor value to L ₁ + L₂ To L₂ only
Switching element Q₁ Increase in current flowing through
I will increase the inclination. This gives the result shown in Figure 34.
Sea urchin, J₁ 《＜ J₂ ‘
It is possible to improve the interval and reduce the harmonic components.

FIG. 12 is a circuit diagram of an eighth embodiment of the present invention.
It In this embodiment, the switch SW is controlled by the output of the control unit 2.
₁And the switching element is switched by the output of the control unit 1.
Child Q ₁Or Q_TenTo turn on / off one of the
It was done. Even when such a configuration is used,
The value of the inductor can be switched, and
The same effect as the embodiment can be obtained.

FIG. 13 is a circuit diagram of the ninth embodiment of the present invention, and FIG. 14 is a circuit diagram of the tenth embodiment of the present invention. These embodiments embody the configuration of the control unit 2 in the embodiments of FIGS. 11 and 12, respectively.
As shown in the operation waveform diagram of FIG. 15, the pulsating current waveform is detected by the resistors R ₁₄ and R ₁₅ , the detector IC ₆ compares it with the reference potential V _6, and the driving unit K ₆ switches the switching element Q ₁₀ or the switch SW. It is configured to drive ₁ .

As in the embodiment of FIG. 11 or 12, switching of the inductance value of at least one stage of the inductors L ₁ + L ₂ and L ₁ and L ₂ is performed in the non-followable section, so that the input current waveform becomes a sine wave. Of the input current can be improved and the harmonic component of the input current can be reduced. However, in order to further improve the sine wave followability of the input current waveform and the harmonic component, it is effective to switch the inductance value in multiple stages as shown in FIG. In the embodiment of FIG. 16, the levels of V ₆ , V ₇ , V ₈ , ..., Vn are changed stepwise, so that the switching elements Q ₂ ′, Q ₃ ′, Q ₄ ′, ..., Depending on the level of the input voltage. It can be turned on in sequence with Qn '. As a result, the inductance value of the chopper circuit can be changed to more finely correct the portion where the input current waveform cannot follow the sine wave. Therefore, the input current becomes closer to a sine wave, and the harmonic component can be reduced. Further, like the embodiment of FIG. 17, the same effect can be obtained by adding the same control as that of the above-described plural stages to the circuit of FIG.

Next, using a saturable inductor, as shown in FIG.
As shown in FIG. 8, if a direct current I is applied to the secondary side, as shown in FIG.
It is generally well known that the inductance L ₁ on the primary side changes as shown in FIG. That is, the variable resistance VR ₁
The inductance value L ₁ can be changed by changing the direct current I by the above method. Therefore, FIG.
In the circuit, such as 0, it is possible to change the inductance value of the chopper circuit by performing using transistors Q ₁₀ controlled as in the embodiment of FIG. 11, following capability and harmonic to a sinusoidal input current The ingredients can be improved. In addition, the control winding of the saturable inductor should be
The input current can be further improved by winding up to the next, ..., Nth order and adding control in multiple stages.

Further, in the characteristic of FIG. 19, the current I is continuously changed between I ₁ and I ₂ at which the inductance value linearly changes with respect to the secondary side current I, and the saturable inductor L ₁ The input current can be further improved by continuously changing the inductance value. For example,
In the circuit shown in FIG. 21, the current I flowing through the secondary side of the saturable inductor L ₁ is made variable by the transistor Q _11, and as shown in FIG. 22, the emitter potential of the transistor Q ₁₁ is a full-wave rectified waveform of the input voltage. (Pulse flow), the base current of the transistor Q ₁₁ has a waveform obtained by subtracting the pulsating current component from the direct current. Therefore, saturable inductor L
Inductance value of ₁ on the primary side varies continuously in accordance with the secondary current I. As a result, the current flowing through the switching element Q ₁ is J ₁ '<as shown by the solid line in FIG.
It can be continuously changed to J ₂ 'and the input current waveform can be further improved.

[0028]

According to the present invention, in the chopper circuit for controlling the ON time of the switching element to be constant after the current of the inductor becomes zero, the control is performed in the section where the input current waveform cannot remarkably follow the sine wave. The input current waveform is improved to follow the sine wave as much as possible by increasing the amount of current in the positive direction of the switching element caused by the delay time of the circuit, and the harmonic component of the input current is reduced. be able to. In addition, by controlling the ON period of the switching element and the value of the inductance continuously or stepwise by using the full-wave rectified waveform, control to increase the positive direction current amount more than the negative direction current amount of the switching element. Can be realized with a simple circuit configuration.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a first embodiment of the present invention.

FIG. 2 is an operation waveform diagram of the first embodiment of the present invention.

FIG. 3 is a circuit diagram of a second embodiment of the present invention.

FIG. 4 is an operation waveform diagram of the second embodiment of the present invention.

FIG. 5 is a circuit diagram of a third embodiment of the present invention.

FIG. 6 is an operation waveform diagram of the third embodiment of the present invention.

FIG. 7 is a circuit diagram of a fourth embodiment of the present invention.

FIG. 8 is a circuit diagram of a fifth embodiment of the present invention.

FIG. 9 is an operation waveform diagram of the fifth embodiment of the present invention.

FIG. 10 is a circuit diagram of a sixth embodiment of the present invention.

FIG. 11 is a circuit diagram of a seventh embodiment of the present invention.

FIG. 12 is a circuit diagram of an eighth embodiment of the present invention.

FIG. 13 is a circuit diagram of a ninth embodiment of the present invention.

FIG. 14 is a circuit diagram of a tenth embodiment of the present invention.

FIG. 15 is an operation waveform diagram of the tenth embodiment of the present invention.

FIG. 16 is a circuit diagram of an eleventh embodiment of the present invention.

FIG. 17 is a circuit diagram of a twelfth embodiment of the present invention.

FIG. 18 is a circuit diagram of a saturable inductor used in the present invention.

FIG. 19 is a characteristic diagram of a saturable inductor used in the present invention.

FIG. 20 is a circuit diagram of a thirteenth embodiment of the present invention.

FIG. 21 is a circuit diagram of a fourteenth embodiment of the present invention.

FIG. 22 is an operation waveform chart of the fourteenth embodiment of the present invention.

FIG. 23 is a circuit diagram of a first conventional example.

FIG. 24 is a high-frequency operation waveform diagram of the first conventional example.

FIG. 25 is a circuit diagram for explaining the operation of the first conventional example.

FIG. 26 is a low-frequency operation waveform diagram of the first conventional example.

FIG. 27 is a high-frequency operation waveform diagram of the second conventional example.

FIG. 28 is a circuit diagram of a third conventional example.

FIG. 29 is a high-frequency operation waveform diagram of the third conventional example.

FIG. 30 is a low-frequency operation waveform diagram of the third conventional example.

FIG. 31 is a high-frequency operation waveform diagram in the valley portion of the pulsating flow waveform of the third conventional example.

FIG. 32 is a high-frequency operation waveform chart in the peak portion of the pulsating flow waveform of the third conventional example.

FIG. 33 is a high-frequency operation waveform chart of the invention of claim 1 or 2;

FIG. 34 is a high frequency operation waveform chart of the invention of claim 3;

[Explanation of symbols]

AC AC power supply DB Full-wave rectifier D ₁ diode L ₁ inductor Q ₁ switching element

Claims (3)

[Claims] 1. An AC power supply, a full-wave rectifier for full-wave rectifying an AC voltage of the AC power supply, and a rectifying output of the full-wave rectifier, which is intermittently accumulated by a switching element to accumulate energy intermittently in the inductor. And a chopper circuit configured to discharge the stored energy of the inductor through a diode for blocking a reverse current, and to turn on the switching element for a certain period after detecting that the current flowing in the inductor has become zero. In a power supply device having a control circuit for controlling, based on the pulsating current waveform after full-wave rectification, the amount of current in the positive direction flowing at least while the switching element is on becomes larger than the amount of current in the negative direction. A power supply device characterized in that a circuit for controlling the ON section of the switching element is added. 2. An AC power supply, a full-wave rectifier for full-wave rectifying the AC voltage of the AC power supply, and a rectified output of the full-wave rectifier which is intermittently accumulated by a switching element to accumulate energy intermittently in the inductor. And a chopper circuit configured to discharge the stored energy of the inductor through a diode for blocking a reverse current, and to turn on the switching element for a certain period after detecting that the current flowing in the inductor has become zero. In a power supply device having a control circuit for controlling, based on the pulsating current waveform after full-wave rectification, the amount of current in the positive direction flowing at least while the switching element is on becomes larger than the amount of current in the negative direction. As described above, the power supply device is characterized in that a circuit for performing control for expanding the ON period of the switching element by one step or more is added. 3. An AC power supply, a full-wave rectifier for full-wave rectifying the AC voltage of the AC power supply, and a switching element for connecting and disconnecting the rectified output of the full-wave rectifier to intermittently accumulate energy in the inductor. And a chopper circuit configured to discharge the stored energy of the inductor through a diode for blocking a reverse current, and to turn on the switching element for a certain period after detecting that the current flowing in the inductor has become zero. In a power supply device having a control circuit for controlling, based on the pulsating current waveform after full-wave rectification, the amount of current in the positive direction flowing at least while the switching element is on becomes larger than the amount of current in the negative direction. A power supply device characterized in that a circuit for performing control so as to change the value of the inductor is added.