JPS6016192B2 - Load power supply device with negative resistance characteristics - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power supply device for a load having negative resistance characteristics, which supplies power to a load having negative resistance characteristics, such as a discharge lamp or a welding machine.

Traditionally, transformers have been used to step up and step down the voltage of power supplies, but such transformers have large cores and conductors made of magnetic material, and their weight also increases, and iron loss in the magnetic material increases. However, the steel loss in the conductor is also large and has the disadvantage of reducing the efficiency of the transformer.

Furthermore, in transformers that supply power to loads with negative resistance characteristics such as discharge lamps and welding machines, the output voltage of the transformer must have a drooping characteristic with respect to the load current, so there is insufficient energy to generate leakage magnetic flux. As a result, the power factor of the transformer decreases significantly, and in order to improve this, it is necessary to add a capacitive element.

In addition, even if buck-boosting is not required, if the discharge phenomenon has negative resistance characteristics, it is necessary to insert an inductance, a resistor, etc. in series as a current limiter to stabilize the operation. In such cases, an inductance is inserted as a stabilizer.

In this case as well, in addition to the inductance element, a power factor improving capacitance element is also required. The present invention eliminates such conventional drawbacks, and the present invention will be explained below with reference to Examples. Embodiment 1 First, FIG. 1 shows a first embodiment of the power supply device of the present invention, which uses a discharge lamp as a load.

In the figure, 1 is a power supply device, to which a discharge lamp 2 is connected as a load. The power supply device 1 consists of a DC power supply 3 (an AC power supply may be used), charging diodes 4, 5, charging thyristors 6, 7, capacitors 8, 9, 10, and discharging thyristors 11, 12. An output voltage three times the output voltage E of the power source 3 can be obtained. Thyristor 6 for charging now
, 7 are closed and the discharging thyristors 1, 12 are open, each capacitor 8, 9, 10G or E is charged in a very short time. After that, the charging thyristor 6,
7 becomes open due to natural commutation when the charging current falls below a certain value, and then a voltage of 3E is applied to the discharge lamp 2 by closing the discharge thyristors 11 and 12, and the discharge lamp 2
When the discharge starting voltage Ed becomes higher than the discharge starting voltage Ed, discharge occurs and the discharge lamp 2
The discharge stops when the discharge stop voltage Ef becomes lower than the discharge stop voltage Ef.
Then, capacitors 8, 9, and 10 are charged again,
Thereafter, charging and discharging are repeated as described above. Although FIG. 1 shows the case of three stages, it goes without saying that in the case of n stages (n≧1), an output voltage of nE can be obtained. The discharge energy E per one cycle of charging and discharging is given by C (F) and the capacitance of the capacitor, and in the case of n stages, E
-(home)2]X10-6 joules, and assuming that the charging/discharging cycle per second is f, the discharge lamp 2 can be supplied with energy of E,×f (watts). Note that depending on the voltage-current characteristics of the load 2, it is also effective to replace the diode 5 or 4, 5 with a thyristor or the like to perform opening/closing control. Embodiment 2 Next, a second embodiment of the present invention will be described with reference to FIG.

In this embodiment, the power supply voltage is stepped down and supplied to a load, and the load includes, for example, a welding arc. After the capacitors 17, 18, 19 connected in series via the charging thyristors 14, 15, 16 are charged by the power supply voltage E from the power supply 13 (or DC power supply) that rectifies the AC power, the charging thyristors 14, 15 , 16 are opened, the discharge thyristors 20, 21, and 22 are closed, and the respective capacitors 17, 18, and 19 are connected in parallel to the load 23 to perform discharge.

In this embodiment, the case where the capacitors 17, 18, and 19 are arranged in three stages is shown, but it can be set to n stages (however, n≧1) depending on the required step-down ratio. The diodes 24 and 25 are discharge diodes for configuring a discharge circuit.
The diode 24 may be inserted as a diode 24' into a line connecting the connection point between the thyristor 16 and the capacitor 8 and the connection point between the diodes 24 and 25 in FIG. In this embodiment, a thyristor is used as a control element and control is performed by natural commutation, but control using a forced commutation element (gate turn-off element) or instead of charging thyristors 15 and 16 is also possible A switching element (diode thyristor) using a negative resistance element or the like may be used.

The repetition frequency of charging and discharging is set so that charging and discharging can be repeated one or more times for each pulsating flow of the power source 13. Embodiment 3 Next, FIG. 3 shows a third embodiment of the present invention, in which a system for continuously adjusting load power, such as a dimming device for a discharge lamp, will be explained using a circuit configuration that does not step up or down the power supply voltage.

Charging thyristor 27 from power supply 26 (or DC power supply)
The capacitor 28 is charged through the capacitor 28, and when charging is completed, the thyristor 27 is opened by natural commutation. Then, the discharge thyristor 29 is closed and the energy stored in the capacitor 28 is supplied to the discharge lamp 30. When discharging is completed, the discharging thyristor 29 is opened by natural commutation, and then the next cycle of charging can be started. At this time, by continuously changing the charge/discharge cycle, the energy supplied to the discharge lamp 30 can be changed continuously, and when the load is a discharge lamp, it can be operated as a dimming device.

Embodiment 4 FIG. 4 shows a fourth embodiment of the present invention in which alternating current is applied to the load.

Although this figure shows the case where the power supply voltage is not increased or decreased, this embodiment can also be applied to the case where the power supply voltage is increased or decreased in the same manner as in the first and second embodiments. Capacitors 34 and 35 are connected in parallel to the output end of a power source 31 that obtains a pulsating current from alternating current via two charging thyristors 32 and 33, and the capacitors 34 and 35 are connected to both ends of a discharge lamp load 36, respectively. Both ends of the load 36 are connected to polarity switching thyristors 37, 3.
It returns to the power supply 31 via 8. When capacitor 34 is discharged, thyristors 39 and 38 are closed, and capacitor 35 is charged, but when thyristors 32 and 3
7,40 is open. When capacitor 35 then discharges, the polarity of the current flowing through load 36 is reversed, thyristors 40, 37 are closed and capacitor 34 is charged, but thyristors 39, 33, 38 are open. Embodiment 5 A fifth embodiment of the present invention will be described with reference to FIG. 5, in which alternating current is supplied to a load in the same way as in embodiment 4.

Reference numeral 41 is a power source, which may of course be a DC power source.

A charging thyristor 42 charges the capacitor 43.

After the thyristor 42 undergoes natural commutation, the discharge thyristor 4
A pair of thyristors, either 4 and 45 or 46 and 47, are closed and supply energy to load 48. On the next discharge cycle, another pair of thyristors close to reverse the polarity of the load current. Embodiment 6 Finally, a sixth embodiment of the present invention will be described with reference to FIG.

During a half cycle in which the AC power supply 49 is positive with respect to the ground potential, the capacitor 52 is charged through the diode 51 from the thyristor 5, and then after the thyristor 50 is opened, the thyristor 53 is closed and a discharge current flows to the load 54. flows.

This charging and discharging is repeated during the positive half cycle of the AC power supply 49, and stops during the negative half cycle, but at this time, the capacitor 57 is charged by the thyristor 55 through the diode 56, and then the thyristor 55 is opened. After that, the thyristor 58 closes, and a current of opposite polarity flows through the load 54. As described above, this embodiment is characterized in that positive or negative discharge currents repeatedly flow during each positive and negative period of the AC power source. In addition,
In cases where the load has negative resistance (such as a discharge lamp), the capacity of the capacitor becomes an important factor in controlling the energy delivered to the load, and the electric power of the discharge lamp and the repeated charging/discharging cycles. It can be determined appropriately depending on the number, etc. Therefore, according to the present invention, the drooping characteristic of the power supply, which is essential when supplying power to a load having negative I resistance characteristics, and the series impedance element, which is essential to the load circuit, are no longer necessary, and furthermore, the charging and discharging of the capacitor is unnecessary. By controlling the cycle, it becomes possible to control the power supplied to the load, and the dimming of discharge lamps, etc., which conventionally required a large reactor device, can be done very easily. In addition, it is of course possible to use thyristors, transistors, forced commutation switching elements (e.g., gate turn-off thyristors), etc. as switching elements, as well as multi-pipetrators, which are conventionally known as gate control signals or base signals. You can also use the output of

According to the power supply device of the present invention as described above, the following effects can be achieved.

01 It is possible to step up and down the voltage without using a transformer, and as a result, it is possible to improve the efficiency of the power supply device.

'2' It is possible to increase the energy density,
It is easy to make the device smaller and lighter.

'3' Energy control can be easily performed by changing the charge/discharge repetition cycle.

[Brief explanation of drawings]

1 to 6 are circuit diagrams of each embodiment of the power supply device according to the present invention. 2, 23, 30, 36, 48, 54...Load,
6, 7, 14, 15, 16, 27, 32, 33, 42,
50, 55... Charging control element, 11, 12,
20, 21, 22, 29, 37, 38, 39, 40, 4
4, 45, 46, 47, 53, 58...discharge control element, 8, 9, 10, 17, 18, 19, 28, 3
4, 35, 43, 52, 57"""Capacitor. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1. Charging a capacitor via a charging control element,
Next, by opening the charging control element and closing the discharging control element, the energy stored in the capacitor is supplied to a load having negative resistance characteristics, and then the discharging control element is opened and the discharge control element is closed again. 1. A power supply device for a load having a negative resistance characteristic, characterized in that the electric power supplied is controlled by repeating charging and discharging and controlling the cycle of this repetition. 2 Charge the capacitor via the charging control element,
Next, by opening the charging control element and closing the discharging control element, the energy stored in the capacitor is supplied to a load having negative resistance characteristics, and then the discharging control element is opened and the discharge control element is closed again. For a load having a negative resistance characteristic, the load is configured to repeatedly charge and discharge, and the polarity of the current flowing through the load is periodically reversed, and the power supplied is controlled by controlling this cycle. power supply.