JP2592675Y2 - Inverter power supply controller for laser oscillator - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser oscillator inverter power supply control device having an improved method for cooling a switching element provided in the laser oscillator inverter power supply control device.

[0002]

2. Description of the Related Art Conventionally, as a method for cooling the heat generated by a switching element provided in an inverter power supply control device for a laser oscillator, heat generated from the switching element is led to radiation fins that come into contact with the switching element, and then radiated by a fan. Cooling the fins, the so-called air cooling method,
A so-called medium cooling method has been adopted in which heat generated from the switching element is guided to a cooling plate in contact with the switching element, and a cooling medium is caused to flow directly inside the cooling plate for cooling.

[Description of FIGS. 1 to 3] FIG. 1 is a diagram showing a conventional inverter power supply control device for a laser oscillator. In the figure, AC is a commercial power supply, and D1 is a low-voltage rectifier having a rectifier diode in a bridge configuration, which performs full-wave rectification of an AC voltage supplied from the commercial power supply AC. C is a smoothing capacitor for smoothing the rectified DC voltage. SW is a switching element, which is a transistor, FET or IGBT (Insul
addedGate Bipolar Transist
or abbreviation) and connect to the full bridge method
The smoothed DC voltage is converted to an AC voltage. T is a step-up transformer, and D2 is a high-side rectifier, which converts the AC voltage boosted by the step-up transformer T into a DC voltage again and supplies the DC voltage to the discharge tube DT. ST is a start-up circuit that outputs a start-up signal St for starting up the laser oscillator to the switching control circuit SC, and the switching control circuit SC outputs a switching control signal Sc for controlling ON-OFF of the switching element SW. Output to SW.

In recent years, the demand for higher output in laser oscillators has been increasing. In order to cope with this higher output, it is necessary to increase the power supplied to the discharge tube DT shown in FIG. . Therefore, the loss of the switching element SW provided on the primary side of the step-up transformer T increases. There is also a demand for cost reduction and downsizing along with higher output, and as a cooling method for the switching element SW, a medium cooling method that satisfies the conditions of low cost and downsizing is becoming the mainstream technology.

FIG. 2 is a diagram showing a conventional medium cooling method for the switching element SW. In the figure, a compound having extremely high thermal conductivity is applied to a contact surface between the switching element SW and the cooling plate CP, and conducts heat due to the loss of the switching element SW to the cooling plate CP. C
L denotes a cooling medium pipe, which removes heat of the cooling plate CP by flowing a cooling medium such as water from a cooling plate medium inlet CLI, and transfers the absorbed cooling medium to the cooling plate medium outlet CLO.
Is flowing out of.

FIG. 3 is a diagram showing a conventional laser oscillator and a medium cooling method for a switching element. In the figure, CCL is a cooling medium circulating device, and it is more economical to use the cooling medium for cooling the laser oscillator LSR to cool the switching element SW than to use a completely independent cooling medium. Normally, as shown by the arrow, the same cooling medium as the cooling medium flowing into the laser oscillator LSR is caused to flow in parallel to the cooling plate medium inlet CLI, and the cooling plate CP which is in contact with the switching element SW.
Is cooled and returned to the cooling medium circulation device CCL again through the cooling plate medium outlet CLO. The laser oscillator LSR is provided with a discharge tube DT shown in FIG. 1, and PC is an inverter power supply control device for the laser oscillator, and includes a switching element SW, a cooling plate CP, a cooling plate medium pipe CL shown in FIG. Cooling plate medium inlet CLI and cooling plate medium outlet CL
O, and a commercial power supply A shown in FIG.
C, a low-side rectifier D1, a smoothing capacitor C, a step-up transformer T, a high-side rectifier D2, a switching control circuit SC, and a start-up circuit ST.

[0020]

The temperature of the cooling medium flowing out of the cooling medium circulating device CCL shown in FIG. 3 is maintained at a constant temperature (for example, 15 degrees Celsius) in order to maintain the characteristics of the laser oscillator LSR. Is controlled. Laser oscillator L
When the SR is in the operating state, the cooling medium circulating device CCL operates and the cooling medium flows into the laser oscillator LSR.
A cooling medium having a constant temperature flows into the cooling plate CP irrespective of the operation of the switching element SW provided therein. Therefore, when the switching element SW is not operating, no heat is generated due to the loss of the switching element SW, so that when the switching element is cooled such as when the ambient temperature is higher than the cooling medium, excessive cooling may occur. . In this case, dew condensation occurs on the surface of the switching element SW, resulting in insulation failure. When the switching element SW is operated and energized, the switching element SW is damaged.

The present invention has been made in order to solve the above-mentioned drawbacks of the prior art. When the switching element SW is not operated, the cooling medium is supplied to the cooling plate C.
An object of the present invention is to provide a highly reliable inverter power supply control device for a laser oscillator that flows into P and prevents dew condensation occurring during excessive cooling, thereby preventing the switching element SW from being damaged.

[0030]

SUMMARY OF THE INVENTION The present invention relates to a laser oscillator inverter power supply control device PC for controlling the output by an inverter circuit using a switching element SW.
A cooling plate CP to which the switching element SW is attached, a cooling plate temperature detection sensor TP that detects the temperature of the cooling plate CP and outputs a cooling plate temperature detection signal Tp, and a temperature around the cooling plate by detecting the temperature around the cooling plate CP A cooling plate peripheral temperature detection sensor TA that outputs a temperature detection signal Ta, and a cooling plate temperature detection signal Tp
A comparison circuit CM that compares the control signal Cm with the cooling plate peripheral temperature detection signal Ta to output an electromagnetic valve control signal Cm, a cooling medium pipe CL for flowing a cooling medium through the cooling plate CP, and an electromagnetic valve control signal Cm connected to the cooling medium pipe CL. This is an inverter power supply control device for a laser oscillator provided with a solenoid valve MV that opens and closes.

[0040]

[Description of FIG. 4] FIG. 4 is a diagram showing an embodiment of a medium cooling method for the laser oscillator LSR and the switching element SW of the present invention. In this figure, the same reference numerals as those in FIG. 3 are the same as those in FIG. In FIG. 4, TP is a cooling plate temperature detection sensor that detects the temperature of the cooling plate CP and outputs a cooling plate temperature detection signal Tp.
TA is a cooling plate peripheral temperature detection sensor that detects the peripheral temperature of the cooling plate CP and outputs a cooling plate peripheral temperature detection signal Ta. CM is a temperature detection signal comparison circuit that compares the cooling plate temperature detection signal Tp with the cooling plate peripheral temperature detection signal Ta and outputs an electromagnetic valve control signal Cm. MV is an electromagnetic valve provided in the laser oscillator inverter power supply control device PC, and controls the flow of the cooling medium flowing from the cooling medium circulation device CCL to the cooling plate medium inlet CLI by the electromagnetic valve control signal Cm.

In FIG. 4, when the laser oscillator LSR is in the operating state, the cooling medium circulating device CCL causes the cooling medium to flow into the laser oscillator LSR and the laser oscillator power supply controller PC, respectively. The cooling medium that has flowed into the laser oscillator LSR returns to the cooling medium circulating device CCL after cooling the laser oscillator LSR. On the other hand, as for the cooling medium flowing from the cooling medium circulating device CCL into the laser oscillator inverter power supply control device PC, when the switching element SW is operating, the switching element SW generates heat due to loss, and the switching element SW is attached. When the temperature of the cooling plate CP exceeds the peripheral temperature of the cooling plate CP, and the cooling plate temperature detection signal Tp exceeds the cooling plate peripheral temperature detection signal Ta, the solenoid valve control signal output from the temperature detection signal comparison circuit CM. Cm becomes an ON signal, and the solenoid valve MV is opened. As a result, the cooling medium flows into the cooling plate CP, cools the heat generated by the switching element SW guided to the cooling plate CP, and then cools the cooling medium circulating device C again.
Return to CL.

Next, when the switching element SW is not operated, the temperature of the cooling plate CP is reduced by the cooling medium flowing into the cooling plate CP because no heat is generated due to the loss of the switching element SW. When the ambient temperature is reached, the cooling plate temperature detection signal Tp becomes equal to the cooling plate peripheral temperature detection signal Ta, the solenoid valve control signal Cm output from the temperature detection signal comparison circuit CM becomes an OFF signal, and the solenoid valve MV is turned off. The circuit is closed, and the cooling medium stops flowing into the cooling plate CP.

When the switching element SW is not operated,
Although there is no heat generation due to the loss of the switching element SW, since the cooling medium pipe CL of the laser oscillator LSR and the cooling medium pipe CL of the laser oscillator inverter power supply control device PC are connected in parallel, the heat of the laser oscillator LSR is reduced. Heat may be transmitted to the cooling plate CP through the cooling medium pipe CL. Also in this case, when the temperature of the cooling plate CP rises and exceeds the ambient temperature, as described above, the solenoid valve MV is opened, and the cooling medium flows into the cooling plate CP to cool the cooling plate CP. , And returns to the cooling medium circulation device CCL again.

Therefore, in order to control the temperature of the cooling plate CP to which the switching element SW is attached by the surrounding temperature of the cooling plate CP, the switching element SW is also controlled by the surrounding temperature similarly to the cooling plate CP. In addition, the condensation of the switching element SW caused by excessive cooling is prevented.

In FIG. 4 showing the embodiment of the medium cooling system of the laser oscillator LSR and the switching element SW of the present invention, the cooling plate temperature detecting sensor is directly attached to the switching element SW instead of being attached to the cooling plate CP. Similarly, the switching element SW is controlled by the ambient temperature, and it is possible to prevent the dew condensation generated due to the excessive cooling of the switching element SW as in the related art.

[0060]

[Effects of the Invention] The present invention relates to the temperature of the cooling plate CP and the cooling plate C.
In order to control the cooling medium flowing into the cooling plate CP to which the switching element SW is attached by the solenoid valve MV that opens and closes based on the solenoid valve control signal Cm output from the temperature detection signal comparison circuit CM that compares the temperature with the surrounding temperature of P. When the peripheral temperature of the cooling plate CP changes, the temperature of the switching element SW changes following the peripheral temperature, and is constantly controlled near the peripheral temperature of the cooling plate CP. Therefore, when the switching element SW is not operating, which is a problem in the related art, the switching element SW is not excessively cooled, and dielectric breakdown caused by dew condensation on the surface of the switching element SW does not occur. Therefore, stable power can be supplied to the laser oscillator LSR because an abnormal situation in which the switching element is damaged does not occur.

[Brief description of the drawings]

FIG. 1 is a diagram showing a conventional inverter power supply control device for a laser oscillator.

FIG. 2 is a diagram showing a conventional medium cooling method for a switching element.

FIG. 3 is a diagram showing a conventional laser oscillator and a medium cooling method for a switching element.

FIG. 4 is a view showing an embodiment of a laser oscillator and a medium cooling method of a switching element according to the present invention;

[Description of Signs] AC commercial power supply D1 Low voltage side rectifier D2 High voltage side rectifier C Smoothing capacitor SW Switching element T Boost transformer DT Discharge tube LSR Laser oscillator MV Solenoid valve CP Cooling plate CL Cooling medium piping CLI Cooling plate medium inlet CLO Cooling plate medium Exit SC Switching control circuit ST Start circuit TP Cooling plate temperature detecting sensor TA Cooling plate peripheral temperature detecting sensor CM Temperature detecting signal comparing circuit CCL Cooling medium circulating device PC Inverter power control device for laser oscillator Sc Switching control signal St Starting signal Tp Cooling plate Temperature detection signal Ta Cooling plate peripheral temperature detection signal Cm Solenoid valve control signal

Claims (1)

(57) [Scope of request for utility model registration] 1. A constant flow discharged from a cooling medium circulation device.
The cooling water controlled to temperature is passed through a laser oscillator to
While maintaining the characteristics of the laser oscillator, the laser oscillation
The inverter circuit that controls the power supplied to the heater
Te laser oscillator inverter power supply controller odor passed through the cooling plate fitted with switching elements, a cooling plate temperature detection sensor outputs the detected cooling plate temperature detection signal the temperature of the cooling plate, the periphery of the cooling plate A cooling plate peripheral temperature detection sensor that detects a temperature and outputs a cooling plate peripheral temperature detection signal; and a comparison circuit that compares the cooling plate temperature detection signal and the cooling plate peripheral temperature detection signal to output an electromagnetic valve control signal. When a cooling medium pipe for flowing a cooling medium to the cooling plate, an electromagnetic valve for opening and closing by the electromagnetic valve control signal to the cooling medium pipe provided, the solenoid valve control signal, the switching
When the element is energized, the temperature of the cooling plate
When the temperature rises above the surrounding temperature of the plate,
Controlling the opening and closing of the solenoid valve so as to cool the
If the switching element is not energized, the temperature of the cooling plate
When the temperature drops to the temperature around the cooling plate,
To prevent excessive cooling,
Is higher than the ambient temperature of the cooling plate,
Control the opening and closing of the solenoid valve so as to cool the cooling plate
Laser oscillator inverter power supply control device for.