JPS6238953B2 - - Google Patents

Description

[Detailed description of the invention]

[Object of the Invention] The present invention relates to a push-pull type transistor inverter device that generates a high-frequency voltage. [Prior Art] Generally, a push-pull type transistor inverter is used as an inverter to obtain alternating current from a direct current power supply, but the switching loss of the transistor that performs the switching operation is large, and the conversion efficiency of the inverter is not very high. I can't. In order to greatly reduce this switching loss, a transistor inverter device is known which is provided with a resonant circuit and an inductance device inside. Fig. 1 shows a conventional transistor inverter device, in which 1 is a DC power supply, 2 is a nozzle filter, 3 and 5 are capacitors of the nozzle filter, 4 is a choke coil used for the nozzle filter, and 14 is a push-pull type. A transistor inverter, 6 has a winding wound N turns around a magnetic core, an inductance device of L (mH), 7 a transformer, 8 and 9 transistors for switching operation, 10 a resonant circuit comprising a chiyoke coil 11 and a capacitor. It is composed of 12. Further, 13 is a load. In the device configured as described above, when transistors 8 and 9 alternately open and close at a frequency close to the resonant frequency of resonant circuit 10, since resonant circuit 10 is present, transformer 7 will generate a sinusoidal waveform. It is possible to generate an alternating current voltage and supply power to the load 13. FIG. 2 shows this operation in an easy-to-understand manner. In other words, if the DC power supply has a voltage E as shown in E, it includes the resonant circuit 10, so
Midpoint N of the primary winding of transformer 7 and transistor 8
The voltage between the emitters 9 and 9 has a waveform obtained by full-wave rectification of the sine wave voltage, as shown in d. At this time, since the voltage of the DC power supply 1 is a direct current as shown in E, the terminal voltage of the inductance device 6 has a waveform as shown in C. Also, the currents of transistors 8 and 9 are
If the impedance of the inductance device 6 is sufficiently large, a waveform with a small peak value as shown in (b) will be obtained. Furthermore, since the voltage between the collector and emitter of the same transistor becomes as shown in A, switching loss during the opening/closing operation of the transistor can be reduced, and the conversion efficiency of the inverter is increased. By the way, in the inverter 14, its transistors 8 and 9 perform a switching operation at a high frequency.
Naturally, noise (high frequency noise voltage) is generated. Further, a line filter disposed on two lines of an AC power source as disclosed in Japanese Utility Model Application Publication No. 146313/1980 has two windings provided in a common magnetic circuit. but. This prevents noise by causing the magnetic fluxes generated by the two windings to cancel each other out due to the load current. In contrast, the present invention uses an inductance device 6 arranged so as to generate magnetic flux in the same direction when the inverter operates. In the device disclosed in Japanese Patent Publication No. 46-22612, coil 3
A reactor 31 consisting of 2 and 33 coils is "wound in the same direction around the central leg of the iron core, and currents flow in opposite directions. Therefore, under normal conditions, the magnetic fluxes of the two coils cancel each other out." In contrast, in the invention of this application, the inductance device 6 generates magnetic flux in the same direction when the inverter operates, and unless it does so, it cannot function as a harmonic choke. [Problems with the prior art] The conventional example shown in FIG. 1 includes a noise filter 2 to suppress the noise (high frequency noise voltage). Although there are various configurations of the noise filter, it is difficult to sufficiently suppress the noise. In order to make it smaller, the noise filter section, such as the chiyoke coil 4, tends to be made larger, resulting in a drawback that the filter 2 becomes larger. Note that in this type of inverter device, the roles of an inductance device such as a chiyoke coil included in the noise filter 2 and an inductance device 6 included in the inverter 14 are different, and the inductance device 6 converts the input current from the DC power supply 1 into a constant current. It has the function of a harmonic wave filter. Like the device of the above-mentioned Japanese Patent Publication No. 46-22612,
If the magnetic fluxes of the two coils of the inductance device cancel each other out, it cannot function as a harmonic choke. In the speed control of an induction motor using a thyristor inverter as disclosed in Japanese Patent Publication No. 46-22612, the inverter generates a frequency on the order of 100Hz at most, but the inverter of this application generates a frequency on the order of 10KHz, for example, when a fluorescent lamp is used as the load. Because they generate such high-frequency voltages, they have little effect on the medium-wave and short-wave bands of broadcast waves, and reducing this noise has become a major issue. [Object of the Invention] An object of the present invention is to miniaturize an inductance device by arranging windings in a common magnetic circuit without increasing the number of magnetic material components, and
In addition to fulfilling its function as a harmonic chiyoke,
An object of the present invention is to provide a transistor inverter device that can reduce noise generated at high frequencies. [Embodiment of the Invention] As shown in FIG. 1. The second windings 16a and 16b are made to generate magnetic flux in the same direction when the inverter 14 operates. In this case as well, it is effective to provide a gap in this transformer as necessary. FIG. 4 shows a transistor inverter device of another configuration using the present invention, in which an AC power source 18 is rectified by a full-wave rectifier 19 via a filter 2 to obtain a DC power source. Note that capacitor 2
The 0 terminal is. It is clear that it corresponds to a DC power supply. Further, the capacitor 20 may be a large-capacity smoothing capacitor, a small-capacity noise filter capacitor, or a capacitor for lowering high frequency impedance on the AC power source side. In the inductance device of this invention, when using the same magnetic core as the conventional device shown in FIG. 1 and performing the same operation, the first winding 16a is N/2
By winding the second winding 16b in N/2 turns, the inductance of the entire inductance device (the inductance measured from the two ends of the inductance device 6 in Example FIG. 4 on the input side, that is, on the noise filter side. , at this time, the two ends on the output side are short-circuited and measured.) can obtain approximately the same size as the conventional inductance device. At this time, the total number of turns of the first and second windings 16a and 16b is equal to that of the conventional device, and the amount of magnetic material is not increased. In addition, the point required for insulation between the windings is that the input DC power supply of the inverter device
If the voltage of DC voltage or less), it is sufficient to insert an insulating tape between the first and second windings 16a and 16b, and the inductance device 6 as a whole does not become larger, and at least the magnetic core of the same size as the magnetic material can be used. Further, the actual measurement results of the difference in noise terminal voltage between the embodiment of the present invention shown in FIG. 3 and the conventional inductance device shown in FIG. 1 are as shown in Table 1 below. In this case, the load is 40W fluorescent lamp 1
Lights, lighting fixtures, and fixtures should be grounded, and DC power supplies should be grounded.
The DC voltage obtained by full-wave rectification of AC100V and the total inductance are 6mH in both Figures 1 and 3.

〔Effect of the invention〕

As described above, according to the present invention, by arranging the windings in a common magnetic circuit as the inductance device 6, noise can be reduced without increasing the number of magnetic material components required to function as a harmonic choke. It also has the advantage that components such as a chiyoke coil used in the noise filter can be made smaller or have a simpler structure. In addition, the inverter of this application generates a high frequency voltage of 10 KHz or more when a fluorescent lamp is used as the load, so the influence on the medium wave band and short wave band of broadcast waves is large, and such high frequency Being able to reduce noise is a major advantage. Although not shown in the explanation of the drawings above, windings 16a and 16b forming the inductance device
Of course, it is also effective to simultaneously ground the core provided with an appropriate reference potential, such as the earth.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a conventional device, FIG. 2 is a diagram for explaining the operation of the conventional device, FIG. 3 is a main part circuit diagram of a device according to an embodiment of the present invention, and FIGS. The figures are circuit diagrams showing devices of other configurations using the present invention. In addition, the same symbols in the figures indicate the same or equivalent parts,
1 is a DC power supply, 6 is an inductance device, 10 is a resonant circuit, 13 is a load, 14 is a push-pull type transistor inverter, and 16a, 16b are windings of a transformer of the inductance device.

Claims (1)

[Claims] 1. A device including a noise filter including a capacitor and a choke coil connected to a DC power source, and a push-pull type transistor inverter having an inductance device and a resonant circuit connected in series with the noise filter, wherein the inductance device is connected to the DC power source. A high-frequency transistor inverter characterized by having windings that are inserted separately into a high-potential side and a low-potential side and generate magnetic flux in the same direction when the inverter operates, and also have a common magnetic circuit. Device.