JP3265671B2 - Inverter device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching type inverter device having an AC power supply as an input.
More specifically, the present invention relates to prevention of inrush current at power-on, improvement of input power factor, and measures against harmonic distortion of input current.

[0002]

2. Description of the Related Art FIG. 19 is a circuit diagram of a power supply device proposed as Japanese Patent Application No. 4-38212. Hereinafter, the circuit configuration will be described. AC power supply Vs is power switch SW
Is connected to the AC input terminal of the full-wave rectifier circuit DB via A small-capacity filter capacitor Cf is connected in parallel to the AC input terminal of the full-wave rectifier circuit DB. An inductor L1 is connected to a DC output terminal of the full-wave rectifier circuit DB via a switching element Q1. A smoothing capacitor C1 is connected to both ends of the inductor L1 via a backflow preventing diode D2. The primary winding N1 of the high-frequency transformer T is connected to both ends of the capacitor C1 via the diode D3 and the switching element Q1. A parallel circuit of a capacitor C5 and a load Z is connected to a secondary winding N2 of the high-frequency transformer T via a series circuit of a diode D0 and an inductor L0. A diode D1 is connected to the series circuit of the inductor L0 and the capacitor C5 with the illustrated polarity. Although not shown, a snubber circuit is connected to both ends of the switching element Q1.

FIG. 20 shows operation waveforms of the circuit shown in FIG. In the figure, I1 is a current waveform flowing through the switching element Q1, and I2 is a current waveform flowing through the diode D2. When the switching element Q1 is turned on, the rectified output voltage of the full-wave rectifier circuit DB is applied to the inductor L1. The inductance value of the inductor L1 is L, and the full-wave rectifier circuit DB
Assuming that the rectified output voltage is Vd and the ON voltage of the switching element Q1 is Vs, the current I1 flowing through the inductor L1
Increases linearly with a slope of di / dt = (Vd−Vs) / L.

Next, when the switching element Q1 is turned off, the electromagnetic energy stored in the inductor L1 is released to the capacitor C1 via the diode D2, and the capacitor C1 is charged. The voltage charged in the capacitor C1 can be increased or decreased by controlling the ON time of the switching element Q1.

Next, when the switching element Q1 is turned on while the capacitor C1 is charged, the primary winding N1 of the high frequency transformer T, the diode D3,
A current flows through the switching element Q1. At this time, the diode D is connected to the secondary winding N2 of the high-frequency transformer T.
A voltage having a polarity for forward-biasing 0 is generated. For this reason,
The diode D0 conducts, and a current flows through the parallel circuit of the capacitor C5 and the load Z via the inductor L0.

Next, when the switching element Q1 is turned off, a back electromotive force is generated in the primary winding N1 of the high frequency transformer T. At this time, a voltage having a polarity for reversely biasing the diode D0 is generated in the secondary winding N2 of the high frequency transformer T. As a result, the diode D0 is turned off, and the energy stored in the inductor L0 is changed to the diode D1.
To the parallel circuit of the capacitor C5 and the load Z. Therefore, the ripple of the voltage across the load Z is reduced. The voltage charged in the capacitor C5 can be increased or decreased by controlling the ON time of the switching element Q1.

In this conventional example, the input power factor is high due to the presence of the chopper circuit, and a low-pass filter such as a capacitor Cf is employed on the input side, so that the harmonics of the input current are high. Low wave components. Further, since the diode D3 is inserted, there is an advantage that an inrush current (inrush current) does not flow from the commercial AC power supply Vs to the capacitor C1 via the inductor L1 when the power is turned on. However, in this conventional example, it is not a resonance inverter, and the voltage waveform and the current waveform of the switching element are enlarged as shown in FIG. There is a delay in the waveform change due to the rising and falling characteristics of the switching element Q1, and when the switching element Q1 is off and on, there is a portion where the voltage waveform and the current waveform overlap as shown by oblique lines. This overlapped portion is a power loss at the time of switching, the loss is large, the circuit efficiency is deteriorated, the amount of generated heat is increased, and a heat radiation measure is required. For this reason, it is necessary to devise a structure such as providing a heat radiating plate for the switching element, and there is a disadvantage that the size is increased and the cost is increased. In addition, there is a disadvantage that electric noise of a high-frequency component is generated due to a steep rise / fall of a voltage generated when the switching element Q1 is turned on / off. In particular, when the discharge lamp load is lit with a rectangular wave, the wiring to the lamp and the lamp itself become an antenna and emit high-frequency noise. In order to prevent this, it is conceivable to electromagnetically shield a lamp or the like, but this is not preferable in view of an increase in cost and a decrease in brightness.

Next, according to the inverter device described in Japanese Patent Application Laid-Open No. 1-160367, an inrush current at the time of power-on is prevented, and a single-input resonance inverter with a high input power factor is provided. Since the supply voltage to the load has a ripple component synchronized with the input frequency of the AC power supply,
There is a problem that the light output does not flicker when the discharge lamp is a load because the voltage is not completely stable without a flat ripple. Also, JP-A-4-127875
The inverter device described in the above publication is not a resonance inverter.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to prevent an inrush current from flowing at the time of turning on a power supply, to provide a high input power factor, By inserting a low-pass filter on the input side, harmonic current can be suppressed, the number of switching elements is small,
An object of the present invention is to provide an inverter device which is small, lightweight, inexpensive, generates little electric noise, and has high circuit efficiency.

[0010]

In order to solve the above-mentioned problems, in the inverter device of the present invention, as shown in FIG. 1, a full-wave rectifier circuit DB for full-wave rectifying an AC power supply Vs is provided.
And one end is connected to one end of the DC output of the full-wave rectifier circuit DB.
The DC output of the full-wave rectifier circuit DB is interrupted at high frequency
A first switching means S1 for causing
The other end of the DC output of the rectifier circuit DB is connected to the first end.
Connected to the other end of the first switching means S1.
DC output of full-wave rectifier circuit DB via switching means S1
A first inductor to which a voltage with a high frequency intermittently applied is applied.
And the other end of the first inductor L1 and the first inductor L1.
One end is connected to the connection point of the switching means S1 with the other end.
A first capacitor C1 for smoothing and a full-wave rectifier circuit
One end is connected to the other end of the DC output of the
A first switch connected to the other end of the first capacitor C1
Second switching which is turned on and off alternately with the switching means S1
One end before the DC output of the full-wave rectifier circuit DB.
A third switching means S3 connected to the one end;
3 switching means S3 and the first capacitor C
A second inductor L2 connected to the other end of the first inductor L2
, A second capacitor C0 connected to resonate with the second inductor L2, and a load circuit Z driven by receiving the resonance voltage of the second capacitor C0. It is characterized in that it is configured to block a current flowing from the full-wave rectifier circuit DB to the first capacitor C1 for smoothing.

[0011]

In the present invention, the AC voltage of the AC power supply Vs is subjected to full-wave rectification by the full-wave rectifier circuit DB, and the output voltage is intermittently applied at high frequency by the switching means S1 and applied to the first inductor L1. Accumulate energy,
Since this electromagnetic energy is discharged to the smoothing first capacitor C1 via the second switching means S2, the period during which the input current from the AC power supply Vs flows can be lengthened, and the input current distortion can be reduced. And the input power factor can be increased. The path through which current flows directly from the DC output terminal of the full-wave rectifier circuit DB to the smoothing capacitor C1 is the third switching means S3.
Therefore, no rush current flows when the power switch SW is turned on. Further, since the load current becomes a resonance current by the second inductor L2 and the second capacitor C0, high-frequency noise is reduced, switching loss is reduced, circuit efficiency is increased, and a heat sink or the like is not required. This makes it possible to reduce the size and cost.

[0012]

FIG. 1 is a circuit diagram of a first embodiment of the present invention.
Hereinafter, the circuit configuration will be described. The AC power supply Vs is connected to an AC input terminal of the full-wave rectifier circuit DB via a power switch SW. A small-capacity filter capacitor Cf is connected in parallel to the AC input terminal of the full-wave rectifier circuit DB. The DC output terminal of the full-wave rectifier circuit DB
The inductor L1 is connected via the switching means S1. A smoothing capacitor C1 is connected to both ends of the inductor L1 via switching means Q2. The inductor L2 is connected to both ends of the capacitor C1 via switching means S3 and S1. The series circuit of the switching means S3 and S1 has a capacitor C0
And a parallel circuit of the load Z are connected. Inductor L2
And the capacitor C0 are connected to the switching means S1, S2, S3
The constant is set so as to resonate at the operating frequency of
Are connected so that power is supplied from both ends of the capacitor C0. The load Z is set to an impedance value that does not significantly impair the resonance between the inductor L2 and the capacitor C0. When freewheel current flows,
Since the internal impedance of the electrolytic capacitor C1 at high frequencies is high, a high-frequency bypass capacitor Ch may be connected in parallel to both ends of the smoothing capacitor C1.

FIG. 2 shows operation waveforms of the circuit shown in FIG. In the figure, (a) is a waveform of a control signal of the switching means S1,
(B) is a waveform of a control signal of the switching means S2,
(C) and (d) are waveforms of the control signal of the switching means S3. As shown in FIGS. 2A and 2B, the switching means S1 and S2 are alternately turned on / off.
First, when the switching means S1 is on and the switching means S2 is off, the rectified output voltage of the full-wave rectifier circuit DB is applied to the inductor L1, and electromagnetic energy is accumulated in the inductor L1. Next, switching means S
When 1 is off and the switching means S2 is on, the electromagnetic energy stored in the inductor L1 is discharged to the capacitor C1 via the switching means S2, and the capacitor C1 is charged. The voltage charged in the capacitor C1 can be increased or decreased by controlling the ON time of the switching means S1.

Next, when the switching means S1 is turned on while the capacitor C1 is charged, if the switching means S3 is turned on, the voltage of the capacitor C1 is applied to the inductor L2. When the switching means S1 is turned off, a resonance current flows through a resonance circuit including the inductor L2 and the capacitor C0. Thus, the switching means S
1 is used as a switching means of a single-pole resonant inverter circuit including an inductor L2, a capacitor C0, and a load Z, and includes an AC power supply Vs, a full-wave rectifier circuit D
B, the inductor L1, the switching means S2, and the capacitor C1 are commonly used as switching means of a chopper circuit.

Next, regarding the switching means S3,
As shown in FIG. 2 (c) or (d), two control methods
There is. As shown in FIG. 2C, the switching means S3 is
When the on / off operation is performed in synchronization with the switching means S1
In case, inrush to capacitor C1 at power-on
Current can be prevented. That is, the switching means
When S3 is turned on, the switching means S1 is turned off.
Switching means S3 and inductor
Inrush current flows to capacitor C1 via L2
Never. Further, the switching means S1 is turned off.
Sometimes, the switching means S3 is also off.
And the switching means S3 and inductor L2
No inrush current flows through the capacitor C1.
In addition, as shown in FIG.
Switching means S1, inductor L1, switching means S2
When it takes time to be fully charged by chopper operation
Interval t ₀ The switching means S3 is turned on after elapse of
Since the capacitor C1 has been charged beforehand,
From power supply Vs to full-wave rectifier circuit DB, switching means S
3, inductor L2, capacitor C1, inductor L
1. The current flowing through the path of the full-wave rectifier circuit DB is suppressed,
Inrush current can be prevented.

FIG. 3 is a circuit diagram of a second embodiment of the present invention. This embodiment embodies the embodiment of FIG. In the figure, Q1 is a switching element, a power bipolar transistor or a power MOSFET, an IGBT.
Etc. D2 and D3 are diodes which are used as switching means S2 and S3, respectively. It is preferable that the diode D4 be connected in anti-parallel to the series circuit of the diode D3 and the switching element Q1. This diode D4 has a function of preventing application of a reverse bias voltage to the switching element Q1.
The switching element Q1 may be inserted to prevent deterioration of the switching element Q1 or to increase the degree of freedom in designing the inverter.

The operation of the circuit will be described below. When the power switch SW is turned on, the input inrush current includes a full-wave rectifier circuit DB, a diode D3, and an inductor L.
2. An attempt is made to flow through the path of the capacitor C1 and the inductor L1, but since it is blocked by the diode D3, no inrush current flows through this path. Further, since the chopper circuit is constituted by the full-wave rectifier circuit DB, the switching element Q1, the inductor L1, the diode D2, and the smoothing capacitor C1, a high input power factor can be secured, and the capacitor Cf is connected to the power input terminal side. By inserting such a low-pass filter, the input current is smoothed into a sine wave, and the harmonic current is reduced.

FIGS. 4 and 5 show operation waveform diagrams of the circuit of FIG. Drawing, v ₀ is the voltage across the discharge lamp FL, i ₀ is the forward direction of the forward current, i ₂ is a diode D2 in the reverse current, i ₃ is the diode D3 of the current flowing through the capacitor C0, i ₄ diodes D4 Current, i ₁ is full-wave rectifier circuit DB
Output current. (A) is a voltage v ₀ across the discharge lamp FL, (b) is a current waveform of each part of the inverter section,
(C) is a current waveform of each part of the chopper. Load Z
Impedance value, since as the value of a degree that does not impair the condition of the resonance system, the current flowing through the load Z is a waveform similar to the current i ₀ which flows substantially in the capacitor C0. A current having a pause section flows through the load Z, and a high-frequency half-wave current is supplied. FIG. 4 is an operation waveform diagram in the case where there is a diode D4 for flowing a free wheel current. Voltage v ₀ across the series connection circuit of switching element Q1 and diode D3
Is given by the resonance between the inductor L2 and the capacitor C0.
It becomes a sine wave half wave. Current flowing through the switching element Q1 is obtained by adding the waveform of i ₁ and i _3, the current (i ₁ +
The degree of overlap between i ₃ ) and the voltage v ₀ is small, and the loss of switching Q1 is significantly smaller than in the case of rectangular wave lighting. Further, since the rise and fall of the voltage v ₀ are not steep, it can be seen that the occurrence of high-frequency noise is suppressed.

FIG. 5 is an operation waveform diagram when there is no diode D4 for flowing a free wheel current. In this case, partial voltage across v ₀ of the series connection circuit of the switching element Q1 and the diode D3 becomes a negative voltage, that is, it can be seen that there is a period for applying a reverse voltage to the switching element Q1. If attention is paid to the application of the reverse bias voltage to the switching element Q1, the diode D4 can be omitted, so that the number of components can be reduced and the cost is also advantageous.

FIG. 6 is a circuit diagram of a third embodiment of the present invention. This embodiment is different from the second embodiment in that the capacitor C
A terminal on the power supply side of the filament of the discharge lamp FL is connected to both ends of 0 through a series circuit of a capacitor C3 and an inductor L3. The capacitor C2 is connected to the non-power supply side terminal of the filament of the discharge lamp FL. The capacitor C3 is for cutting a DC component, and the capacitors C0,
It has a larger capacity than C2 and does not contribute to resonance. The capacitor C2 is a capacitor for resonance, and has a function of supplying a preheating current to the filament of the discharge lamp FL.
The inductor L3 is for resonance and serves as a current limiting element (ballast) for the lamp current of the discharge lamp FL. The inductor L2 has a larger inductance value than the inductor L3. In the present embodiment, the inductor L2 exhibits a constant current action, and provides stable electric power to a tank circuit configured by a resonance circuit including the inductor L3 and the capacitors C0 and C2. It has the function of supplying.

FIG. 7 shows operation waveforms of the embodiment of FIG.
The load circuit including the discharge lamp FL generates an inductive load as a whole.
Make up. When the discharge lamp FL is preheated, switching
The frequency is set sufficiently higher than the resonance frequency,
The resonance effect weakens. At this time, the inductor L2 and the capacitor
Filament of denser C3, inductor L3, discharge lamp FL
Pass through the filament of the discharge lamp FL
A preheating current flows in the path. After a certain time, the switching element
Lower the switching frequency of the child Q1 to approach the resonance frequency.
To strengthen the resonance action, and to both ends of the discharge lamp FL
To apply a high voltage to the lighting of the discharge lamp FL. Release
In order to maintain lighting of the electric lamp FL, the inductor L3 acts as a ballast.
To light stably. Obtained at both ends of the capacitor C0
Voltage v ₀ Is discontinuous, but the coupling capacitor C3
To cut the DC component, and the resonance inductor L3
By utilizing the resonance action of the capacitor C2, discharge
A current (electric power) is continuously supplied to the lamp FL. When lit
, The voltage v across the discharge lamp FL_Two Is the inductor L3
Of the capacitor C3 and the inductor L3
Connection point voltage v_Three Compared to
It is close to a sinusoidal voltage. For discharge lamp FL
The flowing current i is also substantially sinusoidal. This allows
Radiation noise from the wiring to the electric lamp FL and the discharge lamp FL itself
Can be reduced compared to when a square wave is
It can be seen that the components can be reduced. The power of the capacitor C1
Pressure is pure DC with no ripple component due to chopper action
Power supply, the discharge lamp FL is turned on
It can emit flat and stable light.

FIG. 8 is a circuit diagram of a fourth embodiment of the present invention, and FIG. 9 is a circuit diagram of a fifth embodiment. In the embodiment of FIG. 8, a load circuit connected in parallel to both ends of a capacitor C0 in the embodiment of FIG. 6 is connected in parallel to both ends of an inductor L2. In the embodiment of FIG. 9, the capacitor C0 is also connected in parallel to both ends of the inductor L2. In the latter embodiment, a low-pass filter including a capacitor Cf and an inductor Lf is inserted on the AC input side of the full-wave rectifier circuit DB, so that the input current is has a smooth waveform with little distortion, and harmonic components are reduced. Things.

FIG. 10 is a circuit diagram of a sixth embodiment of the present invention. In the present embodiment, the inductor L4 is connected in parallel with the capacitor C2 connected in parallel to the non-power supply side terminal of the filament of the discharge lamp FL. This inductor L4 is also used as a bypass inductor for preventing a DC component from flowing to the discharge lamp FL. The capacitors C0 and C2 and the inductor L3 form a tank circuit and act as a resonance circuit of the inverter. An advantage of this embodiment is that a large-capacity capacitor C3 for cutting DC current can be omitted. Naturally, the inductor L3 also acts as a ballast. Further, the insertion of the inductor L3 at the illustrated location has an effect of preventing high-frequency pulse noise at the time of switching of the switching element Q1 and the diode D3 from returning to the discharge lamp FL.

FIG. 11 is a circuit diagram of a seventh embodiment of the present invention. In this embodiment, the switching element Q1 is used as a switching means for the chopper circuit and the inverter circuit when the load is light such as during preheating. On the other hand, at the time of heavy load such as lighting, a load is applied to the switching element Q1, and in practice, there are few power transistors that can be employed.
Alternatively, it is conceivable that there is almost no case. As a solution, another switching element Q2 is newly added to the diode D.
3 and one connected to both ends of the switching element Q1. When the diode D4 is connected in anti-parallel with the switching element Q2, the switching element Q2 can be constituted by one element by using a power MOSFET as the switching element Q2. This is because a reverse diode parasitic between the drain and source of the power MOSFET can be used as the diode D4.

FIG. 12 shows operation waveforms of the circuit of FIG. Since the load is light during the preheating period, the switching element Q1
Are shared as switching means of the chopper circuit and the inverter circuit, and the switching element Q2 is turned off.
Further, during the lighting period of the discharge lamp, the switching element Q2 is operated exclusively for the inverter and the switching element Q1 is operated exclusively for the chopper because of heavy load during the lighting period of the discharge lamp. The switch S4 is a switch for controlling the preheating current,
It turns on during the preheating period and turns off during the lighting period.

The advantages of this embodiment are that the circuit efficiency is increased and the degree of freedom in design is improved. When the switching element Q1 is shared as the switching means of the chopper circuit and the inverter circuit, there is a power loss due to the forward voltage drop of the diode D3. However, by flowing the current flowing through the inverter circuit to the switching element Q2, The power loss in D3 is reduced.
Further, since the current capacity of the switching element Q1 may be small, the selection range is widened, and the cost is lower than the configuration in which the switching element Q1 is shared, even if the two switching elements Q1 and Q2 are combined. May be.

FIG. 13 is a circuit diagram of an eighth embodiment of the present invention. In this embodiment, a preheating current is supplied via an impedance element Z0 using a secondary winding of an inductor L1 as a preheating power source for a filament of the discharge lamp FL.

FIGS. 14 to 16 are circuit diagrams of ninth to eleventh embodiments of the present invention. In these embodiments, the insulating transformer T is used, and the connection position of the resonance capacitor C0 is different. In the embodiment shown in FIG. 14, a resonance capacitor C0 is connected in parallel with the primary winding N1 of the transformer T.
In the embodiment shown in FIG. 15, a resonance capacitor C0 is connected in series with the primary winding N1 of the transformer T. In the embodiment of FIG. 16, a capacitor C0 for resonance is connected in parallel with the load Z. In these embodiments, the size is increased by use of the insulating transformer T, but it is safe because an electric shock accident at the load Z can be prevented. In particular, when a discharge lamp such as a fluorescent lamp is used as the load Z, an electric shock accident at the time of lamp replacement can be prevented.

FIG. 17 is a circuit diagram of a twelfth embodiment of the present invention. In this embodiment, a large-capacity capacitor C4 is connected in parallel to the diode D3, and a small-capacity capacitor C0 is connected in parallel to the switching element Q1, so that the capacitor C4 has a function of turning off the diode D3. Thereby, the recovery loss due to the reverse recovery current of the diode D3 is eliminated, and an inexpensive diode D3 for low frequency can be used.

FIG. 18 is a circuit diagram of a thirteenth embodiment of the present invention. In this embodiment, a resonance capacitor C0 is connected between the negative electrode of the full-wave rectifier circuit DB and the anode of the diode D3, and a resonance circuit is formed by the inductors L3 and L1 and the capacitor C0. in this way,
By also using the inductor L1 for the chopper as a resonance inductance component of the inverter circuit,
The size of the inductor L3 can be reduced.

[0031]

According to the present invention, an AC power supply is rectified by a full-wave rectifier circuit, and the rectified output is intermittently switched at a high frequency by a first switching means to store electromagnetic energy in a first inductor. Since the electromagnetic energy is entirely injected into the smoothing capacitor via the second switching means, the input current waveform can be made sinusoidal, and the input power factor is increased. . Further, since the third switching means for preventing the output current of the full-wave rectifier circuit from directly flowing into the smoothing capacitor is provided, there is an effect that the rush power does not flow when the power is turned on. Furthermore, since the load current is set to the resonance current by the second inductor and the second capacitor, the radiation of noise is reduced, the switching loss is reduced, and the heat radiation structure can be simplified. There is an effect that can be realized.

When a discharge lamp is used as a load, a stable output voltage without any magnitude of ripple can be supplied to the load by controlling the ON time of the first switching means. There is an effect that an optical output can be obtained.

[Brief description of the 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 a first operation waveform diagram of the second embodiment of the present invention.

FIG. 5 is a second operation waveform diagram of the second embodiment of the present invention.

FIG. 6 is a circuit diagram of a third embodiment of the present invention.

FIG. 7 is an operation waveform diagram of the third embodiment of the present invention.

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

FIG. 9 is a circuit diagram of a 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 an operation waveform diagram of a seventh embodiment of the present invention.

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

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

FIG. 15 is a circuit diagram of a 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 thirteenth embodiment of the present invention.

FIG. 19 is a circuit diagram of a conventional example.

FIG. 20 is an operation waveform diagram of a conventional example.

FIG. 21 is an operation waveform diagram at the time of switching in a conventional example.

[Explanation of symbols]

 S1 First switching means S2 Second switching means S3 Third switching means DB Full-wave rectifier circuit Vs AC power supply L1 First inductor L2 Second inductor C1 First capacitor C0 Second capacitor Z Load

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-359683 (JP, A) JP-A-3-74091 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02M 7/48 H05B 41/24 H05B 41/282

Claims (11)

(57) [Claims] 1. A full-wave rectifier circuit for full-wave rectification of an AC power supply.
When,One end is connected to one end of the DC output of the full-wave rectifier circuit.
The first to interrupt the DC output of a full-wave rectifier circuit at high frequencies
Switching means; One end is connected to the other end of the DC output of the full-wave rectifier circuit,
The other end is connected to the other end of the first switching means,
DC output of the full-wave rectifier circuit through the switching means
A first inductor to which a high-frequency intermittent voltage is applied
And The other end of the first inductor and first switching means
The first for smoothing, one end of which is connected to the connection point with the other end of
And the capacitor One end is connected to the other end of the DC output of the full-wave rectifier circuit.
A first switch having one end connected to the other end of the first capacitor;
Switching turned on and off alternately with the switching means
Means, One end is connected to the one end of the DC output of the full-wave rectifier circuit
Third switching means; Before the other end of the third switching means and the first capacitor
Between the other end A second inductor connected to  A second capacitor connected to resonate with the second inductor
And  A load circuit driven by receiving the resonance voltage of the second capacitor
From the road,  The third switching means is provided for smoothing from the full-wave rectifier circuit.
And configured to block the current flowing through the first capacitor.
An inverter device characterized in that: 2. A full-wave rectifier circuit for full-wave rectifying an AC power supply, and one end connected to one end of a DC output of the full-wave rectifier circuit.
A switch that interrupts the DC output of the full-wave rectifier circuit at high frequencies.
A switching element, one end of which is connected to the other end of the DC output of the full-wave rectifier circuit,
The other end is connected to the other end of the switching element to
High frequency DC output of full-wave rectifier circuit via switching element
A first inductor to which a wave-interrupted voltage is applied
And the other end of the first inductor and the switching element.
A first smoothing terminal having one end connected to a connection point with the other end;
The capacitor and the output of the full-wave rectifier circuit are connected to the other end of the DC output of the full-wave rectifier circuit.
One end is connected so that the polarity is opposite to the force, and the other end is the first connector.
A first diode connected to the other end of the capacitor, and an output of the full-wave rectifier circuit to the one end of the DC output of the full-wave rectifier circuit.
A second diode having one end connected to have the opposite polarity to the force
And over de, the other ends of the first capacitor of the second diode
And a second inductor connected to resonate with the second inductor.
And a load circuit driven by the resonance voltage of the second capacitor.
Inverter apparatus characterized by consisting of a road. 3. A full-wave rectifier circuit for full-wave rectifying an AC power supply, and one end connected to one end of a DC output of the full-wave rectifier circuit.
A switch that interrupts the DC output of the full-wave rectifier circuit at high frequencies.
A switching element, one end of which is connected to the other end of the DC output of the full-wave rectifier circuit,
The other end is connected to the other end of the switching element to
High frequency DC output of full-wave rectifier circuit via switching element
A first inductor to which a wave-interrupted voltage is applied
And the other end of the first inductor and the switching element.
A first smoothing terminal having one end connected to a connection point with the other end;
The capacitor and the output of the full-wave rectifier circuit are connected to the other end of the DC output of the full-wave rectifier circuit.
One end is connected so that the polarity is opposite to the force, and the other end is the first connector.
A first diode connected to the other end of the capacitor, and an output of the full-wave rectifier circuit to the one end of the DC output of the full-wave rectifier circuit.
A second diode having one end connected to have the opposite polarity to the force
And over de, the other ends of the first capacitor of the second diode
, A high-frequency transformer having a primary winding connected thereto, a load circuit connected to a secondary winding of the high-frequency transformer, and a
And a second inductor connected to resonate with the second inductor.
Inverter apparatus characterized by consisting of a capacitor. 4. The inverter device according to claim 2, wherein a third diode is connected in anti-parallel to both ends of the series connection of the second diode and the switching element. 5. The load circuit includes a series circuit of a DC cut capacitor, a ballast inductor, and a discharge lamp, and a preheating current supply capacitor is connected in parallel to a non-power supply side of a filament of the discharge lamp. The inverter device according to claim 2, wherein the ballast inductor and the preheating current conducting capacitor form a resonance circuit. 6. The load circuit includes a series circuit of a ballast inductor and a discharge lamp, and a preheating current supply capacitor and a DC bypass inductor are connected in parallel to a non-power supply side of a filament of the discharge lamp. 3. The inverter device according to claim 2, wherein the inductor for ballast and the capacitor for supplying a preheating current form a resonance circuit. 7. The load circuit according to claim 2, wherein the load circuit includes a series circuit of a third inductor and a discharge lamp, wherein the third inductor is interposed between the second diode and the discharge lamp. The inverter device as described. 8. The switching element according to claim 2, wherein a third diode is connected in anti-parallel to the switching element, and a capacitor for reverse recovery is connected in parallel to the second diode. 3. The inverter device according to claim 1. 9. A second switching element, which operates in synchronization with the first switching element when a load current is large, is connected in parallel to both ends of a series circuit of the second diode and the switching element. Item 9. The inverter device according to any one of Items 2 to 8. 10. The inverter device according to claim 2, wherein a preheating winding for supplying a preheating current to a filament of the discharge lamp is provided in the first inductor. 11. A second capacitor for resonance is connected in parallel with a series circuit of a second diode, a switching element, and a first inductor.
0. The inverter device according to any one of 0.