JPH07255180A - Inverter device - Google Patents

Abstract

PURPOSE:To provide an inverter device where enough protection of a circuit can be made even at abnormal temperature rise. CONSTITUTION:A thermal protector TP is stuck fast to the transistor Q2 being a switching element for chopper of the chopper part of an inverter device, and it is fixed and retained there by a fixing spring 4. The transistor Q2 doubles as a switching element for one inverter of an inverter part. Therefore, since the thermal protector TP is thermally coupled with the transistor Q2 where a load current and a current of a chopper part flow at the same time, the circuit can be protected surely by detecting the abnormal temperature rise caused by the overcurrent at load abnormality quickly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter device having a chopper section and an inverter section, wherein the switching element of the chopper section also serves as one switching element of the inverter section and the circuit is protected when an abnormal temperature rises. It is a thing.

[0002]

2. Description of the Related Art FIG. 12 shows a conventional inverter device with a part thereof omitted. The output is obtained by rectifying the power supply voltage of an AC power supply AC by a diode bridge DB and smoothing it by a smoothing capacitor C ₀ . Is switched by a transistor Q ₀ , which is a switching element, and the output thereof is supplied to a resonance circuit composed of a capacitor C ₅ and an oscillating choke coil L ₅ to light a discharge lamp La, which is a load. It is a lighting device.

In this inverter lighting device, a thermal protector TP is provided on the collector side of the transistor Q _0.
Has been inserted. Here, the discharge lamp La which is a load
Becomes a so-called emilys state in which the emitter, which is the thermoelectron emitting substance of one filament, is consumed at the end of its life. In this emilys state, the discharge lamp La is lit for half a wave, and a direct current flows in the circuit. Therefore, there is a problem in that the transistor Q ₀ and the choke coil L ₅ for oscillation generate heat due to overcurrent, and the inverter lighting device malfunctions. To prevent such malfunction, a thermal protector TP is provided. ,
The circuit is protected.

By the way, in the above-mentioned conventional example, as shown in FIG. 13, the thermal protector TP is attached to the choke coil L ₅ in close contact with the heat-shrinkable tube 16 or tape.

[0005]

On the other hand, in recent years, there has been a demand for effective use of the power distribution system against harmonic distortion, and various active filter circuits based on chopper smoothing have been proposed for that purpose. Further, for the purpose of cost reduction, an inverter device in which a switching element for a chopper and a switching element for an inverter are also used has been proposed (Japanese Patent Laid-Open No. 4-58768).
See Japanese Patent Laid-Open No. 4-33576).

However, in the above-described inverter device which also serves as a switching element, the input current from the AC power supply AC and the load current flowing through the load simultaneously flow through the switching element which also serves as the switching element. When an abnormality occurs in the load and an overcurrent flows in the circuit, such as in the emilys state of the discharge lamp La, the switching element that is also used is compared to other switching elements and choke coil L ₅ that are not also used. And a large current flows. Therefore, the switching element that is also used has the largest load, the heat generation amount is larger than that of the other switching elements, and the failure occurs earlier. Therefore, the thermal protector TP attached to the choke coil L ₅ provides sufficient circuit protection. There is a problem that it cannot be achieved. Also, by using a means for detecting the lamp current or the lamp voltage,
An inverter device that detects half-wave lighting of a discharge lamp and stops the inverter part has also been proposed. However, with such a configuration, the number of parts increases because the detection means is provided, and the inverter device There is a problem that the manufacturing cost increases.

The present invention is intended to solve the above problems, and an object thereof is to provide an inverter device having a simple structure and capable of sufficiently protecting a circuit even when an abnormal temperature rises.

[0008]

In order to achieve the above object, the invention of claim 1 includes a chopper portion provided with a chopper switching element for connecting and disconnecting an input power source obtained by rectifying an AC power source, and a plurality of chopper portions. The inverter includes a switching element for an inverter, and the switching element for the chopper section is alternately turned on and off to convert the output voltage of the chopper section to alternating power and output the alternating voltage. In an inverter device which is also used as a switching element for one of the inverters, a thermal protector for protecting the circuit when the temperature rises abnormally is thermally coupled to the switching element for the chopper.

According to a second aspect of the invention, in the first aspect of the invention, there is provided a holding means for holding the thermal protector and the chopper switching element in close contact with each other. According to a third aspect of the present invention, in the second aspect of the present invention, the holding means is formed in a substantially U shape and holds the thermal protector and the switching element for the chopper by elastic force, and the holding piece is formed substantially in the holding direction. The thermal protector and the chopper switching element in the vertical direction are formed of a restriction piece that restricts movement of at least one of the switching element and the chopper switching element.

The invention of claim 4 is the first to third aspects of the invention.
In the invention described above, the thermal protector is electrically connected to the line where the output of the inverter section is stopped by the interruption and the chopper switching element is not turned on.

[0011]

In the structure of the invention of claim 1, since the thermal protector for protecting the circuit at the time of abnormal temperature rise is thermally coupled to the switching element for the chopper, the switching element for the chopper also serves as the switching element for one inverter. In an inverter device that operates, abnormal temperature rise occurs earlier than other switching elements The abnormal temperature rise of the switching element for the dual-purpose chopper is detected by the thermal protector as soon as possible, and the circuit is reliably protected before it affects other circuit elements. Is what you can do.

According to the second aspect of the present invention, since the holding means for holding the thermal protector and the chopper switching element in close contact with each other is provided, the temperature increase due to the heat generation of the chopper switching element can be reliably detected by the thermal protector. Is what you can do. According to the third aspect of the invention, the holding means is formed in a substantially U-shape, and holds the thermal protector and the switching element for the chopper by elastic force, and a thermal element in a direction substantially perpendicular to the holding direction of the main piece. Since the protector and the switching element for the chopper are formed of a restriction piece that restricts the movement of at least one of the switching elements, the restriction piece prevents the thermal protector and the switching element for the chopper from being misaligned, and prevents the switching element for the chopper from changing. Therefore, it is possible to suppress variations in heat conduction from the thermal protector to the thermal protector, and to easily attach the thermal protector and the chopper switching element to the holding means.

According to the fourth aspect of the invention, the thermal protector operates because the output of the inverter section is stopped due to the interruption and the thermal protector is electrically connected to the line where the chopper switching element is not turned on. As a result, the operations of the chopper section and the inverter section can be stopped at the same time, and the circuit protection of the inverter device can be surely performed.

[0014]

Embodiments In the following embodiments, an inverter device using a discharge lamp La as a load will be described as an example, but the present invention is not limited to this, and an inverter device using another electric device as a load is not limited thereto. It goes without saying that it is okay. First, before specifically describing each embodiment, an example of a circuit of an inverter device A common to the following embodiments is shown in FIG. 7 and will be described. In the inverter device A according to the present embodiment, the power supply voltage of an AC power supply AC such as a commercial power supply is rectified and supplied by a diode bridge DB, and a preheating type discharge lamp La is connected to the output side thereof. , A so-called inverter lighting device, in which the rectified voltage of the diode bridge DB is input to the chopper unit 1 to remove harmonic distortion,
The DC voltage output from the chopper unit 1 is converted into high frequency power by the half-bridge type inverter unit 2, and the high frequency power output from the inverter unit 2 is supplied to the discharge lamp La, which is a load, to light the discharge lamp La. In addition, the starting unit 3 for starting the inverter device A itself is provided.

In the chopper section 1, a series circuit including a choke coil L ₁ and a collector-emitter of a transistor Q ₂ which is a switching element for a chopper is connected between output terminals of a diode bridge DB, and a collector-emitter of the transistor Q _2. A series circuit of a diode D ₁ and a capacitor C ₁ is connected in parallel between them. In the inverter unit 2, the emitter-collector of an inverter switching element composed of transistors Q ₁ and Q ₂ is connected in series, and this series circuit is connected between both ends of a capacitor C ₁ which is an output end of the chopper unit 1. A series circuit of a capacitor C ₂ , a discharge lamp La, an inductor L ₂ , and a primary winding of a current transformer CT is connected in parallel between the collector and the emitter of the transistor Q ₁ , and a transistor Q that is a switching element for a chopper. ₂ is also used as one inverter switching element. The induced voltages of the two secondary windings of the current transformer CT are applied between the base and emitter of the transistors Q ₁ and Q ₂ via resistors to turn on / off the transistors Q ₁ and Q ₂ , respectively. There is. In addition, the current transformer CT has two transistors so that both transistors Q ₁ and Q ₂ are alternately turned on and off.
The secondary windings are connected in opposite polarities.

In order to start this inverter device A,
Capacitor C of chopper unit 1₁2 connected between both ends of
Resistance R₁, R₂And capacitor C₃And a series circuit with
Resistance R₂And capacitor C₃Connection point with transistor Q
₂Trigger element Q inserted between the base and₃With and
The starting unit 3 is provided. This starting unit 3 is
Connection of source AC to capacitor C₁Voltage across
Then the resistance R₁, R ₂Through the capacitor C₃Charge the
And capacitor C₃The terminal voltage of the trigger element Q ₃Blur
When the breakdown voltage is reached, the transistor Q₂On the base of
Apply a starting voltage to the chopper 1 and inverter 2
to start.

By [0017] activating section 3, the transistor Q ₂ is turned on, the charges of the capacitor C _1, the capacitor C ₁ - the capacitor C ₂ - 1 winding of the discharge lamp La- current transformer CT - lamp through the transistor Q ₂ As the current flows, the choke coil L ₁ -diode D ₃ -is connected between the output ends of the diode bridge DB.
A current flows through the transistor Q _2, and an induced voltage for controlling the transistor Q ₁ in the ON direction is generated in the secondary winding of the current transformer CT. After that, the capacitor C ₂ ,
Discharge lamp La, inductor L ₂ , current transformer C
An alternating current flows in the primary winding of the current transformer CT due to the resonance current flowing in the resonance circuit composed of the primary winding of T, and both transistors Q ₁ and Q ₂ are turned on / off alternately.

When the emitter of one of the filaments of the discharge lamp La has been consumed and has disappeared (the emily state), the discharge lamp La is lit for half a wave, and the inverter section 2 is operated for each half wave. Since a large direct current flows, heat is generated in the transistors Q ₁ and Q ₂ or the primary winding of the current transformer CT, which eventually leads to failure. To prevent this, the transistor Q ₁ and
A thermal protector TP is inserted between the emitter-collector connection point of Q ₂ and the primary winding of the current transformer CT. In the conventional example, this thermal protector TP is attached to the current transformer CT and thermally protected. Was bound to.

However, in the inverter device in which one switching element for the inverter also serves as the switching element for the chopper Q ₂ as described above, when half-wave lighting of the discharge lamp La occurs, the transistor Q ₂ does not. Since both the lamp current and the direct current flowing through the chopper unit 1 flow, the amount of current flowing is larger than that of the transistor Q ₁ which is a switching element for the inverter and the current transformer CT, and the amount of heat generated is also increased, which is caused by heat. The damage is larger than other devices.

Therefore, in the present invention, a thermal protector TP is attached to the transistor Q ₂ which is a dual-purpose switching element and thermally coupled to detect the temperature rise due to load abnormality such as half-wave lighting of the discharge lamp La. The overcurrent that flows through the circuit is cut off to ensure circuit protection from abnormal temperature rises. Next, individual embodiments of the present invention will be specifically described with reference to the drawings.

(Embodiment 1) This embodiment will be described with reference to FIGS. As shown in FIG. 1, the outer peripheral surface of the thermal protector TP is provided on the outer peripheral surface of the transistor Q ₂ which also serves as the chopper switching element of the chopper section 1 and the single inverter switching element of the inverter section 2 in the inverter device A. Are brought into close contact with each other and fixedly held by a fixed spring 4 as a holding means, so that the transistor Q ₂ and the thermal protector TP are thermally coupled.

The thermal protector TP is covered with a package made of synthetic resin, and a contact point T ₁ that conducts with a pair of terminal pins 8 planted in the package due to a temperature rise due to heat transferred inside through the package. , T ₂ are separated. Here, the contacts T ₁ and T ₂ are respectively connected to the connection point of the emitter-collector series connection between the transistor Q ₁ and the transistor Q ₂ and the primary winding of the current transformer CT, and normally the contacts are connected. T ₁ , T ₂
Is closed (see FIG. 7).

On the other hand, the fixed spring 4, which is the holding means, is formed by bending a leaf spring into a substantially U shape, and one end piece thereof is divided into three. The divided main piece 4a in the middle is
It extends outside the side pieces 4b on both sides. The width of the main piece 4a is formed to be substantially equal to the width of the thermal protector TP. Further, the tips of the main piece 4a and the side piece 4b are curved outward so that the transistor Q ₂ and the thermal protector TP can be easily inserted. Then, the transistor Q ₂ is inserted between the side piece 4b and the end piece 4c facing the side piece 4b, and further, the thermal protector TP is inserted between the transistor Q ₂ and the main piece 4a so that the transistor Q ₂ and the thermal protector are inserted. The TP and the TP can be held in close contact with each other by the fixed spring 4 and thermally coupled.

According to the above construction, the discharge lamp La is half-wave
When the light turns on and a direct current flows through the inverter unit 2,
Pump current that flows in both the pump current and the current in the chopper unit 1.
Dista Q₂The heat generated at the
Langista Q₂It is fixedly held in close contact with and thermally coupled.
The thermal protector TP is transferred to the
The internal temperature of the le protector TP is
Ascends and eventually contacts T ₁, T₂To open. as a result,
Transistor Q₂The abnormal temperature rise of the
The circuit of the inverter unit A is cut off by cutting off the circuit of the inverter unit 2.
It is possible to protect it. In addition, in this embodiment
Then, the thermal protector TP operates and the contact T₁，
T₂Is separated, the primary winding of the current transformer CT
No current flows through the two transistors Q₁，
Q₂Both remain off and one thermal
Both the chopper section 1 and the inverter section 2 are formed by the tector TP.
One can be stopped at the same time, and the inverter device A
It can be more surely protected.

By the way, as a holding means for holding the transistor Q ₂ and the thermal protector TP in close contact with each other, as shown in FIG. 3, a fixed spring 5 formed by bending a leaf spring into a substantially U-shape may be used. Good. This fixed spring 5
The transistor Q ₂ and the thermal protector TP are inserted between the opposed end pieces 5a and 5b with their outer peripheral surfaces in close contact with each other, and the elastic force of the fixed spring 5 causes the transistor Q ₂
The thermal protector TP and the thermal protector TP are sandwiched together and thermally coupled. The tip of one end piece 5a is curved outward so that the transistor Q ₂ and the thermal protector TP can be easily inserted. However, in the fixed spring 5, the positional relationship between the transistor Q ₂ and the thermal protector TP may be displaced as shown in FIG. 4, and the heat conduction may be varied.

On the other hand, in the fixed spring 4 of this embodiment, the end piece of the side piece 4b is brought into contact with the side surface of the thermal protector TP to prevent the side piece 4b from shifting the thermal protector TP. That is, the main piece 4
The side pieces 4b located on both sides of a are used as the restriction pieces, and the side pieces 4b hold the transistor Q ₂ and the thermal protector T.
The deviation of P can be prevented at the same time, and the thermal coupling between the transistor Q ₂ and the thermal protector TP can be ensured and the variation in heat conduction can be suppressed. Further, there is an advantage that the fixed spring 4 functions as a heat radiating plate to promote heat radiation of the transistor Q ₂ and suppress abnormal temperature rise.

Further, instead of the fixed spring 4, shown in FIG.
Using heat shrink tube 6₂And
-It can also be fixed by closely attaching it to the Mal protector TP.
It is possible. However, according to the fixed spring 4 of this embodiment,
Transistor Q on fixed spring 4 ₂And thermal protector T
Keeping them in close contact with each other by a simple operation of inserting P and
Can be held and fixed using heat shrink tube 6
It has the advantage of being easier to work with than
It

(Embodiment 2) In this embodiment, the shape of the fixed spring 4 in Embodiment 1 is different. As shown in FIG. 6, the fixed spring 7 according to the present embodiment is such that the side pieces 4b are removed from the fixed spring 4 according to the first embodiment, and instead the side wall 7b extends from both side surfaces of the main piece 7a toward the other end piece 7c. Is extended. Then, the transistor Q ₂ is inserted and fixed between the end piece 7c and the end face of the side wall 7b, and a thermal protector TP is further inserted between both side walls 7b to bring the transistor Q ₂ and the thermal protector TP into close contact with each other. It is held by a fixed spring 7.

According to the above construction, the width between both side walls 7b is formed to be substantially equal to the width of the thermal protector TP, so that these side walls 7b serve as restriction pieces to prevent the thermal protector TP from shifting. You can do it. (Embodiment 3) As shown in FIG. 8, an inverter device A according to the present embodiment is a circuit board on which circuit components such as transistors Q ₁ and Q ₂ and resistors R ₁ and R ₂ forming the inverter device A are mounted. 11 is a metal case such as aluminum 10
It is stored in.

The case 10 is made of metal such as aluminum in a box shape.
The circuit component 12 is actually mounted on the bottom of the
The mounted circuit board 11 is housed and fixed. This
Here, transistor Q₁, Q₂Is the center of the circuit board 11.
Mounted facing each other at both ends, thermal conductivity
Of the case 10 with the spacer 13 made of a good member interposed therebetween.
It is fixed to the side wall 10a with a screw 14. But
So transistor Q ₁, Q₂The heat generated in
Conducted to the case 10 via the pacer 13,
The heat is dissipated via. In addition, the spacer 13
Transistor Q without pinching₁, Q₂Directly into case 10
You may attach it.

In the above structure, the transistor Q₁, Q
₂Make sure that the thermal protector TP is closely attached to and fixed to the
Is not easy. Therefore, as shown in FIG.
Using the fixed spring 4 in₁, Q₂
With the side wall 10a of the case 10 in close contact with the side wall 1
0a and transistor Q₁, Q₂And thermal protector T
If P and P are fixedly sandwiched and fixed by the fixed spring 4,
Transistor Q₁, Q ₂And the thermal protector TP
Fixing and holding, transistor Q₁, Q₂Case sidewall
It can be fixed to 10a at the same time. Therefore, tran
Dista Q₁, Q ₂To fix the case to the case side wall 10a
Work that is easy because the screw 14 is not required
Is.

In the present embodiment, the case where the two transistors Q ₁ and Q ₂ are arranged facing each other has been described. However, for example, the two transistors Q ₁ and Q ₂ may be arranged in parallel in the longitudinal direction. It goes without saying that it may have any other configuration. (Embodiment 4) In this embodiment, as shown in FIG. 10, instead of fixing the transistors Q ₁ and Q ₂ and the thermal protector TP to the side wall 10a of the case 10 using the fixed spring 4 of the embodiment 1, The two ends of the thermal protector TP mounted on the circuit board 11 in the longitudinal direction are connected to the transistors Q ₁ and Q.
_By pressing each of the _two to the transistor Q ₁ ,
Each Q ₂ is closely fixed to the side wall 10a of the case 10 to be fixed.

According to the above configuration, the screw 14 and the fixed spring 6
Transistor Q without using₁, Q ₂And thermal protection
Fixed and thermal coupling with the transistor TP and the transistor Q₁，
Q₂Can be fixed to the side wall 10a at the same time, and the assembly work
It will be easier. In addition, thermal protector
Instead of TP, the starting unit 3 and the transistor Q₁, Q₂
The hybrid IC element 15 that integrates the base circuit of
Using the transistor Q as shown in FIG.₁, Q₂To
The side wall 10a of the case 10 is closely attached and fixed.
It is also possible.

[0034]

According to the first aspect of the present invention, a chopper portion having a switching element for a chopper for connecting and disconnecting an input power source obtained by rectifying an AC power source, and a switching element for a plurality of inverters are provided. And an inverter section that alternately turns on and off the chopper section to convert the output voltage of the chopper section into alternating electric power and outputs the alternating power. The chopper switching element of the chopper section is provided in the inverter section.
In an inverter device that also serves as one inverter switching element, the thermal protector that protects the circuit when an abnormal temperature rise is thermally coupled to the chopper switching element, so that the chopper switching element and one inverter switching element are combined. In an inverter device that also serves as an inverter, an abnormal temperature rise occurs faster than other switching elements.The abnormal temperature rise of the dual-purpose chopper switching element is detected by a thermal protector as quickly as possible before the influence on other circuit elements. There is an effect that circuit protection can be performed.

According to the second aspect of the present invention, since the holding means for holding the thermal protector and the chopper switching element in close contact with each other is provided, it is possible to reliably detect the temperature rise due to the heat generation of the chopper switching element by the thermal protector. There is an effect that can be. Claim 3
In the invention of claim 1, the holding means is formed in a substantially U shape to sandwich the thermal protector and the chopper switching element by elastic force, and the thermal protector and the chopper switching in a direction substantially perpendicular to the sandwiching direction of the main piece. Since it is formed of a restriction piece that restricts movement of at least one of the element and the element, it prevents the positional relationship between the thermal protector and the switching element for the chopper from being displaced by the restriction piece, and prevents the switching element for the chopper from moving to the thermal protector. It is possible to suppress variations in heat conduction, and further, it is possible to easily attach the thermal protector and the chopper switching element to the holding means.

According to the invention of claim 4, since the output of the inverter section is stopped due to the interruption, and the thermal protector is electrically connected to the line where the chopper switching element is not turned on, the thermal protector operates. The operations of the chopper section and the inverter section can be stopped at the same time, and the circuit of the inverter device can be reliably protected.

[Brief description of drawings]

FIG. 1 is a diagram showing a state in which a chopper switching element and a thermal protector are inserted and sandwiched in a fixed spring in Embodiment 1, (a) is a side view, and (b) is a bottom view.

FIG. 2 is a perspective view of a fixed spring of the above.

FIG. 3 is an explanatory diagram for explaining an action of the above-mentioned fixed spring.

FIG. 4 is an explanatory diagram for explaining an action of the above-mentioned fixed spring.

5 (a) to 5 (c) are explanatory views for explaining the action of the above-mentioned fixed spring.

FIG. 6 is a perspective view showing a state in which a chopper switching element and a thermal protector are inserted and sandwiched in a fixed spring according to a second embodiment.

FIG. 7 is a circuit configuration diagram of the inverter device according to the first and second embodiments.

8A and 8B show a state in which switching elements for a chopper and an inverter are fixed to a case in Embodiment 3, where FIG. 8A is a plan view and FIG.

9 is a view showing the same as above, showing a state in which a switching element for a chopper and an inverter and a thermal protector are fixed to a case, (a) is a plan view, FIG.
(B) is a sectional view taken along line XX of (a).

10A and 10B show a fourth embodiment, showing a state in which switching elements for choppers and inverters and a thermal protector are fixed to a case, (a) is a plan view, and (b) is (a). 3 is a sectional view taken along line YY of FIG.

11A and 11B show a state in which switching elements for choppers and inverters are fixed to the case of the same by another method, FIG. 11A is a plan view, and FIG. 11B is a side sectional view.

FIG. 12 is a circuit configuration diagram of a conventional inverter device.

13A and 13B show a state in which a choke coil and a thermal protector are in close contact with each other, wherein FIG. 13A is a perspective view and FIG. 13B is a top view.

[Explanation of symbols]

Q ₂ transistor TP Thermal protector 4 Fixed spring 4a Main piece 4b Side piece 4c End piece

Claims (4)

[Claims] 1. A chopper section having a chopper switching element for connecting and disconnecting an input power source obtained by rectifying an AC power source, and a plurality of inverter switching elements for alternately turning on and off these inverter switching elements. An inverter unit configured to convert the output voltage of the chopper unit to alternating electric power and output the alternating voltage, and the switching device for the chopper of the chopper unit also serves as the switching device for one inverter of the inverter unit. An inverter device comprising a thermal protector for thermally protecting a circuit when rising, which is thermally coupled to a chopper switching element. 2. The inverter device according to claim 1, further comprising holding means for holding the thermal protector and the chopper switching element in close contact with each other. 3. The holding means is formed in a substantially U shape and holds a thermal protector and a switching element for a chopper by elastic force, and a thermal protector and a chopper for a chopper in a direction substantially perpendicular to the holding direction of the main piece. The inverter device according to claim 2, wherein the inverter device is formed of a restriction piece that restricts movement of at least one of the switching element and the switching element. 4. The thermal protector is electrically connected to a line in which the output of the inverter section is stopped due to the interruption and the chopper switching element is not turned on. Inverter device.