JPS63265570A - Transistor inverter device - Google Patents

Abstract

PURPOSE:To reduce the power loss and improve the efficiency of the title device, by a method wherein each of a pair of oscillating transistors is provided with a circuit including an oscillating capacitor. CONSTITUTION:A transistor inverter device is constituted of a DC power source 1, an inductance element 2, an oscillating transformer 3, transistors 4, 5 to supply electricity to a load or a discharging lamp 13. In this case, two sets of oscillating capacitors are employed and are connected in parallel between the collecters and emitters of a pair of oscillating transistors 4, 5. According to this method, a voltage, generated in respective windings of the oscillating transformer 3, is oscillated by the leakage inductance of the oscillating transformer 3 and an oscillating capacitor 6b. When a predetermined time has elapsed, the transistor 5 is turned ON. Then, oscillation is generated by the oscillating capacitor 6a in this time and the transistor 5 is turned OFF while the transistor 4 is turned ON. The transistors 4, 5 are turned ON alternately in such a manner whereby an electric power may be supplied from a secondary winding NS to the discharging lamp 13.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a transistor inverter device that converts direct current to alternating current.

[Conventional technology]

FIG. 5 is a circuit diagram of a conventional transistor impark device. In Fig. 5, l is a DC power supply, 2 is an inductance element, 3 is an oscillation transformer, 4 and 5 are transistors,
6 is a resonant capacitor, 7, 8, 9, 12 are resistors, 10 is a diode, 11 is a capacitor, N P l' N P
z is the primary winding, NS is the secondary @ line, NFS is the first feedback winding, and NP is the second feedback winding. Note that 13 is a discharge lamp as a load.

Next, the operation of the transistor impark device configured as described above will be explained with reference to FIG. 6 as well. When a DC voltage is supplied, current first flows through the resistors 7, 8, and 9 to the bases of the transistors 4 and 5. At this time, due to the difference in the amplification factors of the transistors,
For example, if transistor 4 turns on first, a current flows through tlANP, which generates a voltage in the feedback winding NP that increases the base current of transistor 4, and transistor 4 turns on. maintain. On the other hand, since no current flows through the base of transistor 5, it is in an OFF state. In addition, the oscillation transformer 3
The voltage generated in each winding is oscillated by the inductance of the oscillation transformer 3 and the oscillation capacitor 6. Therefore, after a certain period of time has elapsed, the polarity of the first feedback @&INPs is reversed, current flows to the base of the transistor 5, the transistor 5 is turned on, and the disk 4 is turned off.

In this way, when oscillation starts, the voltage generated in the second feedback winding N P 4 is rectified by the rectifier circuit formed by the diode 10 and the capacitor 11, and a DC voltage is generated in the capacitor. This DC voltage is resistor 12,
A drive current is supplied to the base of the transistor 5 via a resistor 8 and a resistor 9.

This drive current is for completely saturating one of the transistors which is in the ON state and causing that transistor to perform a switching operation. In this way, the transistors 4 and 5 are alternately in the ON state and in the OFF state.
The FF state is repeated, and a current made constant by the inductance 2 flows through the transistor which is in the ON state, thereby supplying alternating current to the discharge lamp 13 connected to the secondary @&aNS.

[Problem that the invention seeks to solve]

However, conventional transistor inverter devices have the following drawbacks.

FIG. 6 is a diagram showing the waveforms of the collector current and collector voltage of a transistor in a conventional transistor impark device, and the power loss due to the product of the two. As shown in FIG. 6, the conventional transistor inverter device is a class B switching circuit, and the collector voltage waveform has a shape close to a sine wave, but the current waveform flowing through the transistor has a shape close to a square wave. For this reason, the transistor changes from ON to OFF.
When transitioning from the FF state or OFF state to the ON state, a collector voltage is applied to the transistor even though the collector current is flowing, so the intersection between the collector voltage and the collector current becomes a power loss in the transistor. This was reducing the efficiency of the equipment.

The present invention has been made based on the above circumstances, and an object of the present invention is to provide a transistor inverter device that can reduce the power loss of the transistor and improve the efficiency of the device. [Means for achieving the above object] The present invention includes an oscillation transformer having a plurality of windings, a resonant capacitor that generates an oscillating voltage by resonating with the inductance of the oscillating transformer, and the oscillation e1. In a transistor impark device for converting direct current power into alternating current power, the device includes a pair of oscillating transistors that are alternately rendered conductive by pressure, and one end of the oscillating transistor is connected to each of the pair of oscillating transistors. A circuit is provided that includes the resonance capacitor whose collector and other end are connected to the emitter of the oscillation transistor.

[Effect]

According to the present invention, the waveform of the current flowing through the collector of the oscillation transistor can be improved and made into a sine wave by the means described above, so that the switching tn loss of the oscillation transistor can be reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. FIG. 1 is a circuit diagram of a transistor inverter device according to a first embodiment of the present invention. In FIG. 1, components having the same functions as those of the conventional device shown in FIG. 5 are given the same reference numerals, and detailed explanation thereof will be omitted.

The transistor inverter device shown in FIG. 1 is different from the one shown in FIG. This is the point connected in parallel between .

Next, the operation of the transistor inverter device configured as described above will be explained. When DC voltage is supplied,
First, transistor 4 is connected through resistor 7, resistor 8, and resistor 9.
A base current flows through transistor 5 and transistor 5, and due to the difference in amplification factors of the transistors, for example, transistor 4 is first
Suppose that the state is N. Then, a current flows through the primary winding NPI, and as a result, a voltage is generated in the first feedback '@'h%NPs in a direction that amplifies the base current of the transistor 4, and the transistor 4 maintains an ON state. On the other hand, since no current flows through the base of transistor 5, transistor 5 becomes O
In the zero-order FF state, the voltage generated in each winding of the oscillation transformer 3 oscillates due to the leakage inductance of the oscillation transformer 3 and the oscillation capacitor 6b. Therefore, after a certain period of time has passed, the polarity of the voltage generated in the first feedback winding NPa is reversed, and at the same time, transistor 4 becomes OFF, current flows to the base of transistor 5, and transistor 5 becomes ON. becomes.

As a result, a voltage is generated in the first feedback winding NPI in a direction that amplifies the base current of the transistor 5, and the transistor 5 is maintained in an ON state. Then, vibration is generated by the leakage inductance of the oscillation transformer 3 and the oscillation capacitor 6a, and as a result, after a certain period of time, the polarity of the voltage generated at the first feedback @"kJANP is reversed, and the transistor 5 is turned off. At the same time, the transistor 4 turns on.In this way, when the vibration starts, the voltage generated in the other feedback @ line NP4 is rectified by the rectifier circuit composed of the diode 10 and the capacitor 11, A DC voltage is generated.This DC voltage is used to completely saturate the transistor 4 or transistor 5 which is in the ON state through the resistor 12, resistor 8, and resistor 9, and to cause the transistor to perform a switching operation. Thereafter, the transistors 4 and 5 are alternately turned on to supply alternating current to the discharge lamp 13 connected to the secondary winding NS.

FIG. 2 is a diagram showing waveforms of various parts of the transistor inverter device according to the first embodiment. The collector voltage waveform is approximately a sine wave, and when this collector voltage becomes zero, a base current is supplied to the transistor, so that a collector current flows. Here, the collector current is delayed by a certain phase angle, and a sinusoidal current flows from the collector to the emitter. 1st
Since the voltage generated in the feedback winding NP and the second feedback S line NP is approximately in phase with the voltage generated in the primary winding NPI - NPt, it becomes an oscillating voltage, and the voltage generated in the primary winding NP1 - NPt becomes an oscillating voltage.
When the voltage generated across NPx becomes zero, it becomes zero. When the voltage generated in the first feedback winding N P s becomes zero, the base current is cut off, and the next moment the transistor is reverse biased, so the collector current is suddenly cut off. For example, when transistor 4 is in the ON state, At the same time, capacitor 6
A current flows through a. At this time, since the collector voltage is approximately zero, a transition 1j! occurs when the transistor transitions from the ON state to the OFF state. (switching loss) is small.

Furthermore, when the transistor transitions from the ON state to the OFF state, as shown in FIG. 2, the collector current begins to flow after the transistor becomes the ON state, so the transition loss at this time is almost eliminated.

In this way, according to the first embodiment, the waveform of the collector current is improved to a sine wave, and when the transistor transitions from the ON state to the OFF state, the current flowing through the collector is now flowing into the capacitor. Conversely, when the transistor transitions from the OFF state to the ON state, the collector current lags slightly behind the zero-crossing point of the collector voltage, so the collector current that flows when the collector voltage is applied to the transistor decreases. Thereby, switching loss in the transistor can be reduced.

In the above embodiment, a battery was used as the DC power source, but this may be a rectified commercial power source or a smoothed commercial power source as shown in FIG.

Further, the discharge lamp 13 may be not only a resistive load such as a halogen lamp but also a discharge lamp such as a fluorescent lamp or an inductive load.

FIG. 4 is a circuit diagram of a transistor inverter device according to a second embodiment of the present invention. In FIG. 4, parts having the same functions as those shown in FIG. 1 are designated by the same reference numerals, and detailed explanation thereof will be omitted. The second embodiment shown in FIG. 4 differs from the first embodiment shown in FIG.
A diode 14a having a cathode connected to the collector of the transistor 4 and an anode connected to the emitter of the transistor 4, and a diode 14b having a cathode connected to the collector of the transistor 5 and an anode to the emitter of the transistor 5 are provided. By providing the diodes 14m and 14b, reverse current flowing through the transistors 4 and 5 can be prevented, and switching loss of the transistors can be reduced. Other functions and effects are the same as in the fit embodiment.

Using the second example, AClooV commercial AC was full-wave rectified and supplied to the inverter, and a 12V, 75W halogen lamp was used as the load, and the measurement was performed by lighting at the rated value.
A high conversion efficiency of 95% was obtained.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to improve the collector current waveform of the oscillation transistor and make the waveform a sine wave, thereby reducing the power loss of the transistor and improving the efficiency of the device. It is possible to provide a transistor inverter device that can perform the following steps.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a transistor inverter device according to a first embodiment of the present invention, FIG. 2 is a diagram showing waveforms of each part of the transistor inverter device according to a first embodiment, and FIG. 3 is a diagram of a DC power supply. A circuit diagram showing a modified example, FIG. 4 is a circuit diagram of a transistor inverter device according to a second embodiment of the present invention, FIG. 5 is a circuit diagram of a conventional transistor inverter device, and FIG. 6 is a circuit diagram of a conventional transistor inverter device. Figure 1 shows the waveforms of the collector current and collector voltage of the transistor and the power loss due to the product of the two in DC power supply, 2
...Inductance element, 3...Oscillation transformer, 4
・5... Transistor, 6a, 6b... Resonance capacitor, 7, 8, 9, 12... Resistor, 13... Discharge lamp, 14a14ab... Diode. Applicant: Iwasaki Electric Co., Ltd. Procedural Amendment June 1988//Date Director General of the Patent Office Kunio Ogawa 1, Indication of the case: Patent Application No. 97470 of 1988 2, Name of the invention: Transistor inverter device 3, Relationship with the case of the person making the amendment Patent applicant address: 3-12-4 Shiba, Minato-ku, Tokyo (voluntary) (1) “Discharge lamp as a load” on page 2, line 18 of the specification
It says "Light loads such as halogen bulbs and discharge lamps"
I am corrected. (2) Page 4, line 12 of the specification, page 9, line 2, and line 1 of the specification
In the third line of page 1, the words "discharge lamp 13" are corrected to "electric lamp load 13." (3) In the first line of page 5 of the specification, the text ``18th grade'' is corrected to ``10th grade''. (4) In the 3rd line of page 11 of the specification tube and the 4th line of page 12 of the same,
"Halogen lamp" should be corrected to "Halogen light bulb." (5) On page 11, line 14 of the specification, "r cathode" is corrected to "cathode." (6) On page 13, line 8 of the specification, the word “discharge lamp” should be replaced with “
"Lighting load" is corrected. (7) Figure 6 is corrected as shown in the attached sheet.

Claims (3)

[Claims] (1) An oscillation transformer having a plurality of windings, a resonant capacitor that generates an oscillating voltage by resonating with the inductance of the oscillating transformer, and a pair of oscillating transistors that are alternately rendered conductive by the oscillating voltage. In a transistor inverter device for converting DC power into AC power, each of the pair of oscillation transistors is connected such that one end is connected to the collector of the oscillation transistor and the other end is connected to the emitter of the oscillation transistor. A transistor inverter device comprising a circuit including the resonance capacitor. (2) The transistor inverter device according to claim 1, wherein the circuit including the resonance capacitor is composed only of the resonance capacitor. (3) The circuit including the resonance capacitor is composed of the resonance capacitor and a diode whose cathode is connected to the collector of the oscillation transistor and whose anode is connected to the emitter of the oscillation transistor. The transistor inverter device according to item 1.