JPS6290899A - Electric source for microwave discharge light source - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application J] This invention relates to a microwave discharge light source device for lighting an electrodeless discharge lamp with microwaves [7. In particular, it relates to the improvement of a companion power supply device that fully drives the magnetron that generates the microwaves.

[Conventional technology]

The fourth factor is, for example, the circuit diagram of a power supply device for a conventional microwave discharge light source device shown in Japanese Patent Application Laid-Open No. 57-55091. E is an AC power supply and is the primary winding 1 of transformer T.
AC'1 pressure is applied to fg I P.

The transformer T connects the two secondary windings to IS. It has 2S. A series circuit of the first capacitor C1 and the first diode D1 of the secondary winding 1S, and the second capacitor C2
A series circuit of the first diode and the second diode D2 having the forward current direction opposite to that of the first diode are connected in parallel to form a 0x voltage rectifier circuit, the output voltage of which is applied to the anode and cathode of the magnetron. Also, transformer T 2
The next winding 2S is connected to the cathode (filament) of the magnetron +11. A leaky transformer is used as the transformer T.

The operation of the conventional power supply device as described above is as follows. First, when AC power supply voltage E of commercial frequency (50H2 or 60H1) is applied to transformer T.

The filament of the magnetron (1) is heated by the secondary winding 2S in the transformer, and also by the full wave doubler'4 voltage circuit connected to the secondary winding IS of the transformer T.

A wide pressure is applied to the magnetron, and the magnetron fil
Electric current flows through it and generates microwaves. This microwave energy causes the electrodeless rung to discharge and emit light.

As shown in Figure 5, the microwave output at this time has a rest period in which no microwave is generated.

It becomes a trapezoid shape that lasts about 1 millisecond. This microwave output corresponds to the magnetron current, and the magnetron current also has a trapezoidal shape. This pause period is about 1 millisecond, and the gas being discharged from the electrodeless discharge lamp does not completely return to neutral gas within this pause period, so that the discharge continues.

In addition, as shown in Figure 6, the current voltage characteristic of a magnetron is such that the current changes greatly with respect to changes in voltage. It uses constant current characteristics.

In addition, in this conventional power supply device, the first and second
By changing the capacitance of capacitor C1 and C2, the magnetron output can be changed.

[Problem that the invention seeks to solve]

As mentioned above, in the power supply device of the conventional microwave discharge light source device, in order to change the light intensity of the electrodeless discharge lamp, that is, to perform dimming, the capacitances of capacitors C1 and C2 of the full-wave voltage doubler rectifier circuit must be adjusted. Changing k: This is done by switching several capacitors to change their capacitances, so dimming is done in one step, and continuous dimming is not possible. In addition, because the microwave output pause time occurs every half cycle of the commercial frequency, there is a problem that there is flicker of 100H26 or 120I (Z), which is unpleasant to the eyes.Also, if the transformer T is of the commercial frequency Therefore, there were problems in that it was heavy, inconvenient to handle, and inconvenient to use.

This invention was made to solve this problem, and provides a high-frequency inverter-type power supply device that can continuously control light, has no visible flicker, and is lightweight and drives a magnetron for a microwave discharge light source device. The purpose is to

[Means to solve the problem]

The power supply device according to the present invention converts a commercial frequency power source into a rectifying and smoothing means, a means for high-frequency switching of the rectified and smoothed direct current, a high-frequency leakage transformer, a high-frequency rectifying means, and a microwave-compatible device so that a microwave output can be arbitrarily set. This is a high frequency inverter type power supply device that is equipped with a control means that determines the high frequency switching time based on a control signal. [Function] In this invention, the magnetron current is By using in combination a high frequency leakage transformer that self-suppresses the microwave output and a control means that controls the switching time of the high frequency switching means based on a signal corresponding to the instantaneous value of the microwave output to achieve a preset microwave output. The magnetron current can be made constant due to power supply voltage fluctuations and voltage ripples of the smoothed DC voltage, and an inverter-type power supply device for driving the magnetron can be obtained.

[Embodiment J] FIG. 1 is a circuit diagram of a power supply device for driving a magnetron for a microwave discharge light source device, showing one embodiment of the present invention. In Figure 1, (1) is a magnetron, E is a commercial frequency power supply, (2) is a diode brittle rectifier for rectifying the commercial AC power supply, and Co is a rectifier n7' (a capacitor for smoothing pulsating current). and (4)
is the switching means, and in this actual M example, it is 1M08FET (
Metal oxide field effect transistor Q1 Freewheeling diodes D1 and D2 are connected between the metal oxide field effect transistor Q1 and its source and drain. T is a high frequency leakage transformer and is the IP where the primary winding center tap O comes out.
, has a 2P winding, and one end of the winding MAP is P1.
One end P2 of 2P is the switching transistor Q1
and t'L connected to the drain of Ql,
The center tap of the primary windings IP and 2P is also at the terminal of the smoothing capacitor Co. The sources of switching transistors Q1 and Ql are connected in eight parts and connected to one end of a smoothing capacitor Co. Further, one end S1 of the secondary winding (1S) of the high frequency leakage transformer is also connected to one end S2 through a capacitor C and a diode D.

The capacitor C and the diode D constitute a high frequency, high voltage rectifying means. In this embodiment, a half-wave doubler direct voltage rectifier circuit is constructed, and since (g) is generated at the d terminal and the H6f terminal, the cathode KICf of the magnetron (1) is connected to the anode A at d. To heat the magnetron's filament, current is applied to the left end filament from a commercial AC power source via an isolation transformer (not shown).

Further, 6 is a control means for controlling the switching time of the switching means, and in this embodiment, the switching time is controlled so that the microwave output is set in advance based on the voltage between the DC voltage eo after rectification and smoothing. This is how it was done.

This embodiment belongs to a high-frequency inverter power supply system called a center-wrap system, and uses a switching transistor (h).

By turning Ql ON-OFF alternately.

This is to obtain a high frequency voltage on the secondary side of the transformer T.

The operation of the power supply device configured as described above for driving the magnetron of the microwave discharge light source device according to the present invention is as follows. First, when the power source E is applied, the rectifier and smoothing capacitor Co is charged by the diode bridge DOK. The DC voltage is applied to the primary winding 1 of the high frequency leakage transformer T.
Switching transistor Q1 via P-work 2P
By applying the gate signal voltages rt, Qi and Ql to gl and g2 by the control circuit (6), Ql and Ql are turned ON and OF.
At Fl, a substantially rectangular voltage is induced in the secondary winding 1S of the high frequency leakage transformer T. When the winding direction of the primary and secondary windings of the transformer T is indicated by the mark, when the switching transistor Q1 is ON, the 81 end is (T).
, a voltage is induced so that the S2 terminal becomes (c), a current flows through S through capacitor C and diode D, capacitor C is charged, and Ql becomes QF'F' Ls Q
When l is turned on, voltages of H and S2 are induced in Sl and S2, respectively.

The diode D has a current in the opposite direction, and the magnetron fi
The voltage of capacitor C and the voltage induced in secondary winding IS of transformer T are added between lO cathode and anode.
A voltage is applied to the magnetron, which exceeds the magnetron's operating voltage, causing current to flow through the magnetron and oscillating microwaves. When current flows through the magnetron, the voltage across capacitor C drops.

When the anode-cathode voltage drops below the operating voltage, the magnetron current becomes zero. Next, turn off Ql
When Ql is turned on, capacitor C is charged again.
When Ql is turned ON again, the magnetron (1) current flows and oscillates microwaves. In this way, Ql is turned ON and OFF alternately at high frequency.
The purpose of controlling the FF is high frequency.

The magnetron can be made to oscillate. Shikashi 1
．． The current flowing through the magnetron changes as the applied voltage changes [7
Because of the sudden change, the magnetron power, that is, the microwave output, changes suddenly. Therefore, it is necessary to control the microwave output both instantaneously and on average so that it remains approximately constant at the set value. In this invention, firstly, the high frequency transformer is a leakage transformer, and the voltage n applied to the primary side of the transformer T is
The secondary current of the transformer T is self-suppressed in response to voltage fluctuations, and the voltage applied to the primary side of the transformer, that is, the DC voltage of the rectifier and smoother, is detected, and in response to the instantaneous value of this DC voltage, Switching transistor Q1. Q2's 0N-O
The FF time was controlled to achieve the set microwave output. How to control it will be explained with reference to the drawings. First, if the leakage inductance of the high-frequency leakage transformer T and the capacitance of the capacitor C are set so that the charging and discharging of the capacitor C (current flowing to the magnetron) is completed within the ON time of the switching transistor Q1 and Q2, the second It will look like the figure. The second prisoner takes time on the horizontal axis and the switching transistor Q1
t1 in the figure shows the ON and OFF cycles of Q2 and the charging/discharging current flowing through capacitor C.
And t2 is 08 hours and OFF time of the transistor in the switch, and t5 is when both Q1 and Q2 are OFF. When the switching transistor is turned ON and OFF in this manner, the current charging the capacitor C and the discharge current become as shown in the figure, and charging and discharging are completed within the ON period of the switching transistor. Furthermore, when the DC voltage applied to the high-frequency leakage transformer changes, the charging current and discharging current will be low as shown by the dotted line when the applied voltage is low, and high as shown by the dashed-dotted line when the applied voltage is high. Become. Here, the applied voltage is detected, and based on this, when the applied voltage is high, the switching period to is lengthened, and when the applied voltage is low, the switching period is shortened. V can be controlled so that it remains constant at the set value. In other words, the switching frequency is controlled to be constant for 08 hours of switching.

Furthermore, when the leakage inductance of the high frequency leakage transformer T and the capacitance of the capacitor C are selected so that the switch 7708 time tQ also has a long charging and discharging time, they are controlled as shown in FIG. That is, when the applied voltage is low, the charging and discharging current of the capacitor C is low, and when the applied voltage is high, the charging and discharging current is high. The switching period tp '4 is constant, and if the applied voltage is high, the switch 7708 time tl
i Shorten the switch 770 when the applied voltage is low.
The applied voltage is detected so as to lengthen the time t1 by 8, and based on this, the control circuit (6) controls the switch 7708 time t1 so that the microwave output is set.

Further, in this case, the set microwave output can be obtained even if the switching OFF time t3k is controlled so that it becomes longer when the applied voltage is high and becomes shorter when the applied voltage is low. These controls are performed by comparing the voltage applied within the control circuit with, for example, a reference voltage corresponding to the microwave output, and the reference voltage corresponding to the microwave output is continuously controlled by a potentiometer, etc. Since the light intensity of the electrodeless discharge lamp can be changed, the light intensity of the electrodeless discharge lamp can be continuously adjusted. In addition, the switching frequency can be selected to around 30 KHz, and the microwave output is controlled according to the instantaneous value of the applied voltage, eliminating flickering in the amount of light due to ripples in the applied voltage at twice the commercial frequency. Furthermore, since the switching frequency can be selected to be a high frequency of about 30KH2, the high frequency leakage transformer can use ferrite for the iron core, and the iron core can be made small in size and shape as taught by electromagnetism.

In this example, if a commercial power supply of 200V-501 (Z) is used, the switching frequency is 30KH2, and the input power is 1.5KW, the power supply for the microwave discharge light source device is used. The transformer has an iron core E type (ferrite core) and weighs approximately 0.9 kg, and in terms of electrical characteristics, when the power supply voltage fluctuates by ±10% of the rated voltage, the input power fluctuation is suppressed to approximately -9 yen and +11%. , dimming is possible from 30 to 100 inches depending on the input power.
A leaky transformer uses a bus core between the primary winding and the secondary winding, similar to those used in leaky transformers for commercial frequencies.
Even if the primary winding and the secondary winding are not wound over each other, they can be wound separately and inserted into the iron core (ferrite core) side by side to reduce the closeness of the primary and secondary windings. It was possible to adjust the ELI high frequency leakage transformer. This is easy to manufacture because the ferrite core does not have to have a structure unique to leaky transformers.

As described above, in this embodiment, a center tap type inverter is used, but the present invention is also applicable to other inverter types such as a full glitch type and a No. 7 bridge type. Also.

The switching time was controlled by feedback control by detecting the voltage applied to the primary side of the leakage transformer, but it is also possible to use feedback control by detecting the amount of light, magnetron current, etc. 7-order feedback control may be closed simultaneously.

〔Effect of the invention〕

As explained above, the present invention includes a high frequency leakage transformer and a control means for controlling the switching time of the switching means so that the microwave output becomes a preset microwave output by a signal corresponding to the microwave output generated from the magnetron. When used together, a power supply device for driving a magnetron for a high-frequency inverter-type microwave discharge light source device can be obtained, the high-frequency leakage transformer becomes lightweight, and by using a high frequency, it is possible to eliminate flicker that can be felt by the eyes. Furthermore, since the value of the reference signal corresponding to the microwave output applied to the control means for controlling the switching time can be changed continuously, there is an advantage that continuous dimming can be performed.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of an embodiment of a power supply device for driving a magnetron of a microphone R:1V discharge light source device according to the present invention. Figure 2 is a flowchart of switching ON and OFF' when detecting the rectified DC voltage and controlling the switching frequency of the microwave output in Figure 1, and a diagram showing the charging and discharging current waveforms of capacitor C. Figure 3 shows how to detect the DC voltage after rectification and switch the microwave output.Switching frequency control ON/OFF 7
A diagram showing charge/discharge waveforms of capacitor C and capacitor C. FIG. 4 is a circuit diagram of a power supply device of a microwave discharge light source device using a conventional commercial frequency power supply, and FIG. 5 is a diagram showing a microwave output waveform of the power supply device shown in FIG. 4. FIG. 6 is a diagram showing the voltage-current characteristics of the minetron. In the figure, (l) is a magnetron, and (2) is a rectifier. (3) is a smoothing means, (4) is a switching means, T is a high frequency leakage transformer, (5) is a rectifying means, and (6) is a switching time control means. The same reference numerals in the drawings indicate the same or corresponding parts. Figure 2: Kanoma, Figure 3: Time opening, Figure 4: 2 rods, 5 A Figure 6

Claims (3)

[Claims] (1) In a power supply device for driving a magnetron of a microwave discharge light source device for lighting an electrodeless discharge lamp using microwaves, the power supply device includes a means for rectifying a commercial frequency power source, a means for smoothing the rectified voltage, and the smoothing means. means for switching smoothed direct current at high frequency; a high frequency leakage transformer for obtaining a high frequency by connecting a primary winding to the switching means; a high frequency rectifier circuit connected to the secondary winding of the high frequency leakage transformer; A power supply device for a microwave discharge light source device, comprising: a control means for controlling a switching time of the switching means based on a signal corresponding to the microwave output so as to provide a microwave output. (2) The control means detects the smoothed DC voltage and controls the switching frequency so that the microwave output becomes a preset electric power based on the detected DC voltage. power supply. (3) The control means detects the smoothed DC voltage, and based on the detected DC voltage, controls the switching ON time of the switching means so that the microwave output becomes a preset electric power. power supply.