JP3259391B2 - 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 an inverter device for converting a DC input power into an arbitrary low frequency voltage to drive a load circuit.

[0002]

2. Description of the Related Art FIG. 11 is a circuit diagram of a conventional inverter device.
It is. V₁ Is a DC power supply, for example, 12V for vehicle
Battery. CHP is a boost chopper,
Inductor L for boost₀ , L₁ And switching element Q
₀ , Backflow preventing diode D₀And smoothing condensate
Sa C₀ And a low-voltage DC power supply V₁ And boost,
For example, a voltage Vc of about 300 V is created. Switchon
Element Q₀ Is on, the inductor L₀ Energy
The switching element Q₀ Is off,
Energy from DC power supply V₁ Superimposed on the
Voltage Vc to capacitor C₀ To supply. INV is a step-down cho
A rectangular wave inverter that also serves as
Child Q₁ , Q_Two , Q_Three , Q_Four And the diode D₁ , D_Two ,
D_Three , D_Four , Current limiting inductor L_Two , From the load circuit Z
Switching element Q₁ , Q_Two , Q _Three, Q_Four The switch
By controlling the switching frequency and duty,
The power supply to the load circuit Z is controlled. The load circuit Z is
Discharge lamp LP and inductor L for low-pass filter_Three Passing
And capacitor C₁ And load from inverter INV
The current flowing to the circuit Z has a substantially triangular-wave-like high-frequency ripple.
Therefore, this high-frequency ripple is_Three And con
Densa C₁ Reduced by a low-pass filter consisting of
Thus, rectangular wave power is supplied to the discharge lamp LP.
The discharge lamp LP is composed of a high-pressure discharge lamp, for example, a headlight of an automobile.
It is used for lamps.

FIG. 12 is an operation waveform diagram of the inverter INV. The switching elements Q ₁ and Q ₃ operate at high frequency (Equation 1).
0 Number of 100 KHz), the switching element Q _2, Q ₄ performs low-frequency operation (several tens to several hundreds of 100 Hz). When the switching elements Q ₁ and Q ₄ are simultaneously turned on, the capacitor C
_{From 0} , a current flows through the path of the switching element Q ₁ , the inductor L ₂ , the load circuit Z, the switching element Q ₄ , and the capacitor C ₀ , and supplies power to the load circuit Z. At this time,
Energy is stored in the inductor L _2. Next, when the switching element Q ₁ is off, the switching element Q ₄ is ON, the energy of the inductor L ₂ becomes commutated to power, the inductor L _2, the load circuit Z, the switching element Q _4, a diode D _2, inductor It is released in the path of L _2. Supplying power to the load circuit Z is controlled by the switching frequency and duty of the switching elements Q ₁ and variable. Next, when performing polarity inversion,
As shown in FIG. 12, first, the switching elements Q ₂ , Q
₃ co turned on, then off only switching element Q _3, by turning on the diode D _1, it causes the step-down chopper operation.

[0004]

In the above-mentioned conventional example, since the circuit structure is complicated and the number of parts is large, the overall shape of the inverter device tends to be large, and applications where mounting space is limited (for example, Mobile bodies such as automobiles and airplanes) have drawbacks such as difficulty in securing an installation location.

[0005] Therefore, as shown in FIG. 13, the switching elements Q ₁ ,
A method in which Q ₂ , Q ₃ , and Q ₄ are shared (Japanese Patent Application No. 3-343)
224) has been proposed. FIGS. 14A and 14B are operation waveform diagrams, wherein FIG. 14A shows the switching element Q ₁ , FIG. 14B shows the switching element Q ₃ , FIG. 14C shows the switching element Q ₂ ,
(D) shows the operation of the switching element Q _4. In this method, there is a case where sufficient power control is not effective with respect to load impedance fluctuation. As a specific example, in FIG. 13, the impedance of the load Z is low,
When the voltage across the load Z is lower than the voltage of the DC power source V ₁ was, the current flowing through the inductor L ₂ is not zero. Thus, for example, as in the case of the output line to the load Z is short-circuited to the ground line GND, when the load Z abnormality, stops the power supply from the DC power source V _1. Therefore, turning off the switching element Q ₁ to Q _4, for energy stored in the inductor L _2, both ends abnormally high voltage of the inductor L ₂ is generated, the damage to the switching element Q ₁ to Q ₄ give. Therefore, a method of adding a snubber circuit or the like to both ends of the switching elements Q _{1 to} Q ₄ can be considered. However, when it is necessary to supply a large amount of power when the load Z has a low impedance, the snubber circuit or the like can be used. There is a drawback that the shape of the protection circuit becomes large and the inverter device itself becomes large.

The present invention has been made in view of such a point, and an object of the present invention is to make an output voltage to a load circuit compare with a power supply voltage of a DC power supply, for example, when a load is short-circuited. An object of the present invention is to provide a power supply device that can easily perform power control even in a small size with a simple circuit configuration and small size.

[0007]

FIG. 1 shows a basic configuration of a power supply unit according to the present invention. The configuration of the load circuit Z is shown in FIG.
In a similar to that in the conventional example shown, in which a capacitor C ₁ connected in parallel to a series circuit of the discharge lamp LP and the inductor L _3. One end of the load circuit Z is connected to the positive pole of the DC power supply V ₁ through the inductor L ₁ and the switching element Q _1, is connected to the negative electrode of the DC power source V ₁ through the switching element Q _2. The other end of the load circuit Z is connected to the positive pole of the DC power supply V ₁ through the inductor L ₂ and the switching element Q _3, a switching element Q ₄
It is connected to the negative electrode of the DC power source V ₁ via. Diodes D ₁ and D ₃ are connected in anti-parallel to the switching elements Q ₁ and Q ₃ , respectively. Inductor L ₁ and L ₂ are magnetically coupled to constitute a step-up transformer. Further, the polarity is set in the illustrated direction.

[0008]

FIG. 2 is an operation waveform diagram of the present invention. Switchon
Element Q₁ , Q_Three Alternates at low frequency (several Hz to several hundred Hz)
On and off. Switching element Q_Two Is switchon
Element Q₁ The switching element Q
_Four Is the switching element Q _Three Is in the section where
ON / OFF at high frequency (several kHz to several hundred kHz)
You. This switching element Q_Two , Q_Four Up and down by the action of
Operate the pressure chopper. Also, the switching element Q
₁ , Q_Two And switching element Q_Three , Q_Four The switchon
Of the voltage supplied to the load circuit Z by switching the
Switch polarity.

For example, in a section between t ₁ and t ₂ , when the switching elements Q ₁ and Q ₂ are on, the DC power supply V ₁ switches the switching element Q ₁ , the inductor L ₁ , the switching element Q ₂ , and the DC power supply V ₁ current flows through a path, energy switching element Q ₂ is corresponding to the peak current value immediately before oFF is stored in the inductor L _1. Next, when the switching element Q ₂ is turned off, the energy stored in the inductor L ₁ is an inductor L _1, it is released as a current from the inductor L ₂ which are magnetically coupled. This current flows from the inductor L ₁ to the load circuit Z, inductor L ₂ , diode D ₃ , switching element Q ₁
Through, through a path back to the inductor L _1. At this time, the capacitor C ₁ has the polarity as shown in FIG.
c ₁ is charged.

Subsequently, in a section from t ₂ to t ₃ , both the switching elements Q ₁ and Q ₂ are turned off, the switching element Q ₃ is turned on, and the switching element Q ₄ is turned on / off at a high frequency. reversing the polarity of the capacitor C _1. When the switching elements Q ₃ and Q ₄ are on,
Energy is accumulated in the inductor L _2. Next, the switching element Q ₃ is turned on, when the switching element Q ₄ is off, releasing the energy from the inductor L _1, L ₂ to the load circuit Z.

With the above operation, the capacitor C ₁
The current Iz flowing through the voltage across Vc ₁ and the discharge lamp LP,
As shown in FIG. 2, a low-frequency rectangular wave is obtained. In the figure, f ₁
Is the frequency at which the switching elements Q ₂ and Q ₄ switch at a high frequency, and f ₂ is the frequency at which the current Iz flowing through the load alternates at a low frequency. In this circuit, the load circuit Z
Is short-circuited or the like, when supplying power to the load circuit Z, if all the energy stored in the inductors L ₁ and L ₂ is released because the DC power supply V ₁ is disconnected, the switching is performed. It is no problem to turn off all the elements Q ₁ , Q ₂ , Q ₃ , Q ₄ . Therefore, the voltage Vc ₁ across the load circuit Z may be lower than the voltage of the DC power supply V ₁ , and the controllability is improved as compared with the conventional example of FIG. Further, as compared with the conventional example of FIG. 11, the circuit configuration is simplified, and the inverter device itself is downsized.

[0012]

FIG. 3 is a circuit diagram of a first embodiment of the present invention.
FIG. 4 is an operation waveform diagram of the present embodiment. In this embodiment, bipolar transistors are used as the switching elements Q ₁ , Q ₂ , Q ₃ , and Q ₄ . The switching elements Q ₂ and Q ₄ have diodes D ₂ and D ₄ respectively.
Are connected in anti-parallel, and diodes D ₅ and D ₆ are connected in series. These diodes D ₂ , D ₄ , D ₅ ,
D _6, a voltage is added to prevent from being applied in the opposite direction to the switching element Q _2, Q _4. Other configurations are the same as the basic configuration shown in FIG. Note that in the load circuit Z, if you are ready high-frequency component flows to the load LP, inductor L ₃ and capacitor C ₁ of the low-pass filter is not required.

Hereinafter, the operation of this embodiment will be described.
The basic operation is the same as the basic configuration shown in FIGS.
However, control at the time of polarity reversal for the load circuit Z
In order to facilitate the switching element Q₁ , Q_Three Behavior
Timing is slightly different. First, t in FIG.₁ ~ T_Two Between
Is the switching element Q₁ , Q_Two Is on,
Power supply V₁ , Switching element Q₁ , Inductor L₁ ,
Diode D_Five , Switching element Q_Two , DC power supply V₁ 
The current flows through. Also, the switching element Q₁ But
ON, switching element Q_Two Is turned off,
L₁ , Load circuit Z, inductor L_Two , Diode D
_Three , Switching element Q₁ , Inductor L ₁ Through
The current flows. Also, t in FIG._Two Nearby, Conden
Sa C₁ Voltage Vc₁ When the polarity of the
Ching element Q₁ , Q_Three Switch on and off instantly
Is difficult in practice, the switching element Q
₁ , Q_Three Are turned on at the same time and then turned off.
U. Next, t in FIG._Two ~ T_Three Between the switching elements
Q_Three , Q_Four Is on, the DC power supply V₁ ,switch
Element Q_Three , Inductor L_Two , Diode D₆ , Sui
Switching element Q_Four , DC power supply V₁ Current flows through
You. Also, the switching element Q_Three Is on, switching
Element Q_Four Turns off, the inductor L_Two , Load circuit
Z, inductor L₁ , Diode D₁ , Switching element
Child Q_Three , Inductor L_Two The current flows through. More than
Due to the operation, the load current Iz becomes as shown in FIG.
A low-frequency rectangular wave current flows. The effect of this embodiment is the basic structure.
This is the same as when the load is low, such as when a short circuit occurs.
Invar with low impedance and easy to control
Data device.

FIG. 5 is a circuit diagram of a second embodiment of the present invention, and FIG. 6 is an operation waveform diagram of the second embodiment. In this embodiment, power MOSFs are used as the switching elements Q ₂ and Q _4.
If you are using ET, also arranged on the higher potential side of the DC power source V _1. Illustrating the configuration of a drive circuit of the switching element Q ₂ in FIG. The high-frequency signal is output from the inverter N ₁
And input to the bases of the transistors Tr ₁ and Tr ₂ . The collector of the NPN transistor Tr ₁ is connected to the power supply Vcc, and the collector of the PNP transistor Tr ₂ is connected to the ground. Each transistor Tr
The emitters of ₁ and Tr ₂ are DC cut capacitors C
₂ is connected to the primary winding of the pulse transformer PT. The high-frequency voltage obtained in the secondary winding of the pulse transformer PT is applied to the switching element Q via the resistors R ₁ and R _2.
Input to the gate of ₂ . Further, although the switching elements Q ₁ and Q ₃ on the low potential side are driven at a low frequency, they can be driven without using a pulse transformer, so that the drive circuit for the switching elements can be downsized. Therefore, the inverter device can be downsized.

FIG. 8 is a circuit diagram of a third embodiment of the present invention. In this embodiment, in the embodiment of FIG. 3, the configuration step-up transformer, the two divided inductors L _1, L _2, by the four-divided inductors _{L 1, L 11, L 2} , L 21, DC it is facilitated from the power supply V ₁ increases the step-up ratio of the voltage Vc ₁ of the capacitor C _1.

FIG. 9 is a circuit diagram of a fourth embodiment of the present invention.
FIG. 10 is an operation waveform diagram thereof. This embodiment is a
It is turned on and off at a high frequency in the first period and is turned on in the second period.
The first switching element Q₁ And in the second period
The second is turned on / off at a high frequency and turned off in the first period
2 switching element Q_Two And first and second switches
Element Q₁ , Q_Two DC power supply V to which the series circuit of
₁ And the first and second switching elements Q₁ , Q_Two Contact
A first inductor L having one end connected to the connection point₁And the first
Inductor L₁ Through the first switching element Q₁ 
Connected in parallel to the second switching element Q_Two Synchronized with
Switching element that is turned on and on in a high-frequency manner
Q_Three And a first inductor L₁ Through a second switch
Element Q_Two Connected in parallel to the first switching element
Q₁ A fourth switch which is turned on and on at a high frequency in synchronization with
Switching element Q_Four And third and fourth switching elements
Q _Three , Q_Four The load circuit Z connected to the connection point
Nacta L_Two And a third circuit via the series circuit.
Switching element Q_Three Connected in parallel during the first period
Fifth switching turned off and turned on in second period
Element Q_Five And a fourth switching through the series circuit.
Element Q_Four Connected in parallel during the first period and
Switching element Q that is turned off during the period₆ And from
It consists of First inductor L₁ And the second indah
Kuta L_Two Are magnetically coupled to form a step-up transformer
I have. The polarity is in the direction shown.

The operating principle of this embodiment is the same as the above-described embodiments, firstly, to accumulate energy in the inductor L _1, then the energy to the load circuit Z from the inductor L _1, L ₂ The operation of the step-up / step-down chopper that discharges air is performed. Polarity inversion of the load circuit Z is carried out by changing the direction of current when storing energy in the inductor L _1. The advantage of this circuit is that the withstand voltage of the switching elements Q ₁ , Q ₂ , Q ₃ , Q ₄ can be reduced by increasing the turns ratio N ₂ / N ₁ of the inductors L ₁ , L ₂ ,
Further, the number of windings of the step-up transformer can be easily reduced as a whole as compared with the embodiment of FIG. 8, and the size of the step-up transformer can be reduced, and the withstand voltage of the switching element can be reduced.
In particular, when the switching element is a semiconductor such as a MOSFET, the reduction of the withstand voltage facilitates the reduction of the on-resistance at the time of conduction. Therefore, the loss of the switching element is reduced, the heat radiation design and the like are facilitated, and the size is reduced. Will be possible.

FIG. 10 is an operation waveform diagram of the present embodiment. Figure
10 t₁ ~ T_Two , The switching element Q₆ But
The switching element Q₁ , Q_Four But
When on, DC power supply V₁ , Switching element Q₁ ,I
Nacta L₁ , Diode D _Four , Switching element Q
_Four , DC power supply V₁ A current flows in a path passing through. Also,
Switching element Q₁ , Q_Four Is off, the inductor
L₁ , Load circuit Z, inductor L_Two , Diode D₆ ,
Switching element Q₆ , Diode D_Two , Inductor L
₁ A current flows in a path passing through. Also, t_Two ~ T_Three Section of
And the switching element Q_Five Is on,
Switching element Q_Three , Q_Two Is on, the DC power supply V
₁ , Switching element Q_Three , Diode D_Three , Indac
L₁ , Switching element Q_Two , DC power supply V₁ Passing through
Current flows in the road. Also, the switching element Q_Three , Q_Two 
Is off, the inductor L₁ , Diode D₁ ,
Switching element Q_Five , Diode D_Five , Inductor L
_Two , Load circuit Z, inductor L ₁ Current flows through the path
It is. By these operations, the load current Iz is
A low-frequency (several tens to several hundreds Hz) rectangle as shown in FIG.
Wave current flows.

[0019]

According to the present invention, even if the load has a relatively low impedance with respect to the power supply voltage, the DC power supply is not short-circuited via the switching element and the load, so that power control can be easily performed. There is an effect that it is possible to provide an inverter device that can perform the operation.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a basic configuration of the present invention.

FIG. 2 is an operation waveform diagram of the basic configuration of the present invention.

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

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

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

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

FIG. 7 is a circuit diagram of a drive circuit used in a second embodiment of the present invention.

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

FIG. 9 is a circuit diagram of a fourth embodiment of the present invention.

FIG. 10 is an operation waveform diagram of the fourth embodiment of the present invention.

FIG. 11 is a circuit diagram of a first conventional example.

FIG. 12 is an operation waveform diagram of the first conventional example.

FIG. 13 is a circuit diagram of a second conventional example.

FIG. 14 is an operation waveform diagram of the second conventional example.

[Explanation of symbols]

V ₁ DC power source LP discharge lamp Q ₁ switching element Q ₂ switching element Q ₃ switching element Q ₄ switching elements L ₁ inductor L ₂ inductor L ₃ Inductor C ₁ capacitor D ₁ diode D ₃ diode

──────────────────────────────────────────────────続 き Continuation of the front page (72) Takashi Kamihara, Inventor 1048, Oaza Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works, Ltd. (56) References JP-A-4-359895 (JP, A) Jpn. (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) H02M 7/48 H02M 7/5387 H05B 41/24 H05B 41/282

Claims (4)

(57) [Claims] A first switching element that is turned on and off at a low frequency; and a first switch that is turned on and off at a high frequency while the first switching element is on .
A second switching element that will be turned off during switching element is off, the other end of the DC power source via the second switching element is connected to one end of the DC power source through a first switching element a first inductor connected, the first switching element and the third switching element that is turned in the off, the third on-off switching element is in a high frequency in the period is on, the third
The on period switching device is turned off Ru is off 4
A switching element, a second inductor connected to one end of the DC power supply via a third switching element, and connected to the other end of the DC power supply via a fourth switching element, and a first inductor. A load circuit having one end connected to the connection point of the second switching element and the other end connected to the connection point of the second inductor and the fourth switching element; and antiparallel to the first and third switching elements, respectively.
Inverter device comprising a diode connected to the inverter. 2. The inverter device according to claim 1, wherein the first inductor and the second inductor are magnetically coupled. 3. The inverter device according to claim 1, wherein the load circuit is configured by connecting a capacitor in parallel to a series circuit of the discharge lamp and the third inductor. 4. A first switching element which is turned on and off at a high frequency in a first period and is turned off during a second period, and a first period which is turned on and off at a high frequency in a second period A second switching element that is turned off in step 1, a DC power supply to which a series circuit of the first and second switching elements is connected, and a first power supply having one end connected to a connection point between the first and second switching elements. An inductor, a third switching element connected in parallel to the first switching element via the first inductor, and turned on and on at a high frequency in synchronization with the second switching element; The fourth switching element is connected in parallel to the second switching element and turned on and on at a high frequency in synchronization with the first switching element.
, A series circuit of a load circuit and a second inductor connected to a connection point of the third and fourth switching elements, and a first circuit connected in parallel to the third switching element via the series circuit. A fifth switching element that is turned off during the period and turned on during the second period; and a fifth switching element that is connected in parallel to the fourth switching element via the series circuit and is turned on during the first period and during the second period. And a sixth switching element to be turned off.