JPS5883585A - Power source device - Google Patents

Abstract

PURPOSE:To obtain a high frequency power having constant amplitude as an output and improve the line current distortion of a 3-phase power source by converting powers of polyphases into high frequency powers and superposing them in series with each other. CONSTITUTION:Inverters 4, 4', 4'' have the same oscillating frequency of the inverter, and are allowed to cross at zero at the same timing by operating the inverter 4 as a controller and obtaining the all switching signals from the inverter 4. The secondary side of the transformer T is connected so that the generated high frequency becomes the same phase, thereby synthesizing the high frequency power. In this manner, powers of polyphases are converted to high frequency power, are superposed in series, thereby largely improving the line current distortion of the 3-phase power source.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power supply device using a three-phase power supply, and is an improved version of the line current type three-phase power supply.

FIG. 1 shows an example of a circuit of a conventional power supply device, and FIG. 2 shows waveforms of various parts. In Fig. 1, diodes D1 to D and a full-wave rectifier bridge are connected to the three-phase 'Rt source l, which is converted into a DC voltage v'oc, and this DC voltage is input to the inverter 2. It is configured to convert the signal into a high frequency signal and apply it to the load 3. FIG. 3 shows a specific circuit example of the inverter 2, in which transistors Qx-Q2 and a transformer T constitute an oscillation circuit. The load 3 may be anything that uses alternating current power, such as an electric motor, and there is an example in which the inverter 2 controls speed-up and counterfeiting. Further, if DC power is used, the inverter 2 may be omitted. By the way, in this type of power supply device, the input three-phase alternating current is full-wave rectified by the rectifier diodes D and %D, so the input voltages of each phase are compared. In other words, if we consider the cow cycle of one phase voltage, the other two
Power is supplied to the 2/37c section where the voltage is higher than that of the phase, and to the load. Therefore, the line current waveform from the 3-phase "#It source is paused by 1/3π radian during a half cycle, as shown in Figure 2. It has a form that is exclusively 2/3π radian.When the strain rate of this current-resistant wire is actually measured, it is -27 according to an example.
He showed great value as a person. A large distortion factor means a large Fj6 harmonic component, which naturally increases loss in the power transformer. Furthermore, in a three-phase power supply, since the secondary output is connected in delta, a short km current due to the 3rd harmonic flows, further increasing the loss. As a result, the efficiency of the power transformer decreases, and it is possible to draw less power than originally designed.Conversely, if this point is taken into account in the design, the equipment becomes larger than necessary, which is uneconomical. Furthermore, most of the loss generated within the transformer turns into heat, which shortens the life of the transformer, and conversely, increasing the heat-resistant design results in increased costs. As the number of power conversion devices increases due to the development of electronic technology, it is expected that the above-mentioned drawbacks caused by linear flow will become more of a problem.

The present invention was proposed in view of the above points, and involves converting the power of multiple phases into high-frequency power and connecting each phase in series to obtain cylindrical frequency power with a substantially constant amplitude as an output. It is also an object of the present invention to provide a power supply device that can greatly improve the linear flow of three-phase power, thereby reducing loss in a power transformer, and making the entire device more compact and highly efficient.

The invention will now be described in detail with reference to the drawings, which illustrate the principle of operation and embodiments.

FIG. 4 shows the basic operating principle of the present invention.

The dotted lines of v12 # v31 e ■ are each 3
This is the voltage of the phase power supply and is a sine wave with a phase difference of 9120 degrees (2/ax radian). A feature of three-phase alternating current is that the sum of the instantaneous power of each phase is always constant and independent of time. In other words, constant power can be supplied to the load while maintaining the AC input current of the three-phase power supply in a sine wave shape. In a single-phase power supply, the original power varies sinusoidally, and it is not possible to provide constant power to the load while reducing AC input current distortion. The three-phase full-wave rectification system shown as a conventional example in Figure 1 also takes advantage of this feature.
At first, I increased the AC input current.

In order to take advantage of the characteristics of a three-phase power supply, it is necessary to make it possible to superimpose each three-phase AC power, but if the three-phase AC power is superimposed, the total voltage will be 0, so it will be difficult to supply power to the load. Can not. Therefore, in the present invention, it is possible to superimpose each power by converting each of the three-phase alternating current into a high frequency. As shown in FIG. 4, when each of the three-phase alternating currents is converted to a high frequency wave that crosses zero at the same frequency and at the same timing, the voltage in this example is V. The high frequencies corresponding to ■ and I are in phase, and the voltage vl! It can be seen that the high frequency corresponding to the former has a phase difference of 180 degrees from the former. In other words, when looking at a certain time t0, there are only two types of voltage: positive direction voltage and negative direction voltage. It is easy to superimpose two alternating currents with a phase difference of 180 degrees into the same phase. For example, if a transformer is used, the connection on the secondary side may be changed. Therefore, each power of the three-phase alternating current can be reduced to 1 tatami, and by superimposing them in series, it is possible to obtain still frequency power whose amplitude is constant regardless of time. The fact that the amplitude is constant is the result of the power of each of the three phases being superimposed and converted to a high frequency, so there is no need to worry about obtaining constant power.

FIG. 5 shows the above-mentioned operating principle in a concrete circuit configuration, where l is a three-phase X source, 4.4'.

4 is an inverter, and 3 is a load. Further, its operating waveforms are shown in FIG. However, inverters 4 and 4'.

In order to make the oscillation frequency of each inverter the same and to cause the inverters to cross zero at the same timing, the inverter 4 also serves as a control section, and 3-, all switching signals are obtained from the inverter 4. Then, the secondary side of the transformer T is connected so that the high frequencies generated are in the same phase.
Synthesizing high frequency power.

Although the above circuit alone can provide sufficient effects, the present invention has been further improved to make it possible to reduce the number of inverters.

Another possible method for reducing the distortion of the AC human power *'g flow of a three-phase power supply is the one shown in Figure 8. FIG. 7 is an explanatory circuit, in which a current similar to that at a certain line point is applied to the inverter 5. This is indicated by current line 2, and similar current line 21.5 is applied to other inverters 5.5.
Give the engineering, . In this case, linear flow work is electric current work 12 @
``It is expressed as the sum of ``Im'' and becomes a continuous waveform as shown in Figure 8. Other line currents l8. When considering a certain time t, only the electric currents 8 and Xu are flowing at this time.In other words, only two inverters 5 and 5 are operating.For another time t2, This is the same, and only inverters 5 and 5 are operating.In other words, by providing a rest angle to the input current to the inverters, the two inverters are operated in 1 m order, and the distortion of the AC input line current is reduced. - According to the example, the 10th
Using the resonant push-pull inverter shown in the figure, the fourth
By arranging the same oscillation operation as shown in the figure, it works to supply a constant power from the part between the two lines, so the inverter input current waveform is triangular and the line current shape is cedar-shaped9.
A linear ft and a strain rate of 5% were obtained. This is less than 115 in the conventional example shown in FIG. The frequency and amplitude of the output are substantially constant.

FIG. 9 shows a first embodiment of the present invention, which has a more specific configuration based on the principle of FIG. 8. 3 phase power line P
, and P, are directly connected to one input terminal of the inverter 6.6', and apart from that, the line P1 is connected to the other input terminal of the inverter 6 through the switch 8W4, and the line P, is connected to the other input terminal of the inverter 6 through the switch 8W. Connected to another input terminal. The line 2 connects the switch 6 and the switch SW via the switches sw, , sw,
It is connected to the connection point between the inverter 6' and the switch SW4. FIG. 11 shows an example of the operation algorithm of each switch, and the shaded area means on. In this example 1
/3π radians bKk number of switches are turned on and off,
The connection part of the computer can be changed. Looking at this algorithm, switch SW, SW,
, SW, and SW4 are in opposite phases to each other, and it can be seen that the phases of switches 8W and 8W are shifted by 1/3π radian. In other words, by creating an on-off pattern for switches SW2 and 8W, and completely reversing switches SW1 and 8W, all on-off patterns (turns) can be created. Figure 12 shows the timing chart, and The figure shows a specific example of the circuit. In the timing chart of FIG. 12, l is the switch sw,
, Q,' corresponds to the on/off pattern of switch 8W2, so is it a flip-flop? .

The inverted output ζ of switch 8W4, flip-flop? ,
The inverted output ζ may be used to turn on and off the switch SW1. The operation can be easily understood since, for example, time t1 in FIG. 8 corresponds to T1 in FIG. 11, and time t2 corresponds to T2. The sweet SW, ~SW, can be anything that can force AC or VR, and here it is a diode bridge DB! '~DB4' and transistor, I~Q4
′ combination was used. Note that pa is a clock pulse generator.

FIG. 14 shows a second embodiment of the present invention, in which the output of FIG. 9 is rectified and purified by a diode bridge DB and a capacitor CJ, and then a switch Ql'l QC and a capacitor CI.
IC! , diodes D, , D are used to convert the alternating current into rectangular alternating current and supply it to the load. For example, when applying direct current to a load, transmitting power as a high frequency and rectifying it will have a large effect on attenuation and noise on other equipment, and it can be used in cases where direct current may cause galvanic corrosion of the contacts. It has the advantage that direct current can be easily obtained by simply rectifying it on the side. Moreover, it goes without saying that the input current distortion of the three-phase power supply can be reduced.

The M2S diagram shows the application of the present invention to a discharge lamp lighting device [7
The high frequency power obtained by reducing the output of the inverter 6,6' is directly supplied to the discharge lamp LA. By the way, in a discharge lamp lighting device using an inverter in a single-phase TM, when the AC input current distortion was measured, it was a storm of about 30 degrees, as an example, and the distortion caused by 8 effects was large. In order to increase the luminous efficiency of a multi-hole lamp and save power, it is desirable to keep the high frequency amplitude constant by using a DC power supply, but if you try to obtain DC from a single-phase power supply, the distortion will further increase. result. That is, it has not been possible to reduce the distortion of AC input current and increase the luminous efficiency of the discharge lamp with single-phase tV. According to this example, a high frequency wave with a constant amplitude can be obtained while reducing AC input current distortion, so that the luminous efficiency of the discharge lamp increases and power saving can be achieved.

As described above, the power supply device of the present invention includes a group of switches that appropriately switches the three-phase power and distributes it to the two-system guns, and at least two inverters that generate high-frequency power and receive the power supply through the group of switches. and a control part a that synchronizes the oscillation period of the inverter, and synchronizes each inverter's oscillation power so that it crosses 0 at the same timing, so that each phase or each linear force has a phase difference of 0 or 180 degrees. Since it is converted into high frequency power and each high frequency power is connected in series with the same phase, AC input current distortion can be made extremely small, and a constant power can be obtained as an output. It is possible to achieve higher efficiency, smaller size, and lower cost. In addition, it has the effect of greatly reducing noise generated on the power line and eliminating interference with other equipment.

Although the above description has focused on a three-phase electrical helix, it goes without saying that the present invention can also be applied to a -film length phase alternating current.

[Brief explanation of the drawing]

Fig. 1 is an example of a circuit of a conventional power supply device, Figs. 2 and 3 are explanatory diagrams thereof, Fig. 4 is a diagram of the basic operating principle of the present invention, Fig. 5 is an example of a circuit embodying the principle, and Fig. Figure 6 is an explanatory diagram of its operation.
Fig. 7 is a diagram of the principle of the present invention, Fig. 8 is an explanatory diagram of its operation,
9 is a circuit diagram showing the first embodiment of the present invention, FIG. 10 and FIG. 13 are diagrams showing partial details thereof, FIG.
2 is an explanatory diagram of the operation, FIG. 14 is a circuit diagram showing a second embodiment, and FIG. 15 is an example in which the present invention is applied to a discharge lamp lighting device. 1...3-phase power supply, sw, , gw, , sw,
, gw4...Switch, 6.6...Inverter, 3
...Load, DB, DB1'. DB; , DB; , DB: 3 DB'...Diode bridge (flow diverter), GLl r C4, C1
' + Q'z' @ C3' + C4', Q+'
# C2'...Switching element (transistor)
, DI, D2...diode, C1* Cz + CG
ICO"" capacitor, Fl, F2-7 lip-flop, G...gate, PG...clock pulse generator, "0...inductance, EB...m current 'R7
Source patent applicant-397-= Figure 6

Claims (1)

[Claims] (1) A group of switches that appropriately switches the three-phase power and distributes it to two systems, and two inverters that receive the power supply through the switch group and generate high-frequency power, and the oscillation period of the inverter. The oscillation waveforms of each inverter are synchronized so that they cross zero at the same timing, and each phase or each linear force is converted into high-frequency power with a phase difference of 0 or 180 degrees. A power supply device characterized by obtaining high-frequency power with a substantially constant amplitude by superimposing high-frequency power in series in the same phase. The inverter receiving power supply through the inverter is equipped with two inverters that generate high-frequency power and a control unit that synchronizes the oscillation cycles of the inverters, so that the oscillation power of each inverter becomes zero at the same timing, Synchronize each phase or each linear force so that each phase difference is 0 or 18
By converting to high frequency power at 0 degrees, and connecting each high frequency power in series with the same phase, high frequency power with approximately constant amplitude is synthesized, and connected to the output terminal, 9" rectification and smoothing is performed. A power supply device characterized in that a circuit rectifies and smoothes frequency power, converts it into DC power, and obtains rectangular pulses using a series inverter.