JPS6115557B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention provides a series lighting circuit in which a plurality of lamps are lit from a constant current type AC power source such as a constant current regulator (hereinafter referred to as CCR) through an isolation transformer. Since the voltage and current resurge waveforms are deformed due to the delay in the rise of the CCR output current due to the magnetic saturation of the connected isolation transformer, a series lighting circuit that detects the number of broken lamps from the area of the resurge waveform is developed. This invention relates to a core breakage detection device.

Conventionally, LC resonant circuits as shown in Figure 1 have been applied as power sources for airport runway lighting, and CR-type CCR
11 is used.

In Figure 1, 1 is a sine wave AC power supply 111 is an input transformer, 112 is a brightness selector, 113 is a resonant circuit composed of LC, 114 is an output transformer, and 12 is the primary side of an isolation transformer 121 connected in series. This is a series lighting circuit in which a lamp 122 is connected to each secondary side.

The CR type CCR takes advantage of the fact that the current flowing through the load remains constant regardless of the load amount by selecting L and C.Since the circuit is relatively simple and the price is low, it is currently widely used as a power supply for series lighting circuits. used at airports.

The CR type CCR has a simple circuit configuration and is manufactured at low cost, and usually does not have a lamp breakage detection device or a breakage monitoring device. For this reason, the current situation is that specialized maintenance personnel go around checking for broken lamps, or replace broken lamps as pointed out by pilots, which poses maintenance problems.

The present invention has been made to solve the above problems, and provides a simple and reliable series lighting circuit breakage detection device that detects the amount of lamp breakage from the area of the resurge waveform. .

FIG. 2 is a block diagram of a core breakage detection device according to an embodiment of the present invention. In Figure 2, 21 is the first
Series lighting circuit 12 using the transformer PT shown in the figure
A voltage detector 22 detects the voltage at the input terminal of and outputs a voltage signal v, and a voltage detector 22 detects the circuit current of the series lighting circuit 12 using a current transformer CT shown in FIG. 1 and outputs a current signal i. 2 is a microprocessor consisting of an input/output interface 23, an arithmetic unit 24, a storage unit 26, and an oscillator 25;
23 is an input/output interface having analog-to-digital converters 231 and 232; 27 is a digital display that uses an LED _or the like to display a display signal Ao from the microprocessor 2; and 28 is an alarm signal from the microprocessor 2. This is an alarm device that uses A _S to activate a buzzer and lamp to issue an alarm.

FIG. 4 shows an example of a resurge waveform displayed on a cathode ray tube using a voltage signal υ and a current signal i in the configuration as described above.

If there is no broken lamp, please use the method shown in Figure 4a.
The voltage signal υ and current signal i from the CCR become a sine wave with a constant value selected by the brightness selector 112,
The phase angle α _a of the current signal i with respect to the voltage signal υ shows a slight delay due to the impedance of the series lighting circuit 12 . As a result, the resurge waveform R _a is the fourth
As shown in Figure b, it becomes almost a straight line.

When some of the lamps are broken, the isolation transformer connected to the broken lamp will undergo magnetic saturation, and the rise of the current signal i will be slow until the isolation transformer reaches magnetic saturation, as shown in Figure 4c. The current waveform i′ is distorted from the sine wave as shown in . The distortion at this time, that is, the phase shift angle α at which the current rises steeply
_b is significantly delayed compared to the case without a core break lamp. The phase angle α _b of this delay changes with the number of isolation transformers 121 that are magnetically saturated. As a result,
The resurge waveform R _b is deformed as shown in FIG. 4d.

The area formed by the resurge waveform increases approximately in proportion to the number of core-broken lamps. If the area of this resurge waveform is determined by the microprocessor 2 configured as shown in FIG. 2, the alarm signal A _S can be easily output.

The operation will be explained below using the waveform diagram in FIG. 3 and the flowchart in FIG. 5. The clock pulse C _P of the oscillator 25 is frequency-divided in the arithmetic unit 24 and the frequency (1.8 kHz) is 360 times that of the voltage signal υ (50 Hz).
Create a sampling palace _SP . voltage signal υ
and the current signal i are input to the analog-to-digital converter 23
1,232, the digital voltage signals υ ₀ , υ ₁ , . . . are A/D converted in synchronization with the sampling pulse S _P during the sampling time, respectively.
...υ ₃₅₉ and digital current signals i ₀ , i ₁ , ...i ₃₅₉ .

In the calculation unit 24, the digital voltage signal υ
₀ , υ ₁ , ...υ ₃₅₉ , the zero voltage value is detected and used as a start signal, and the sampling pulse S _P
The digital voltage signal υ _o and the digital current signal i _o are read in synchronization with and stored in the respective memories of the storage unit 26 . In this way, one cycle of the voltage signal υ is read, that is, 360 times, and each
After storing 360 pieces in memory, finish reading and set the center point 0 of the Lissage waveform in Figure 3b and τ
_o (found from υ _o and i _o ) and τ _o+1 (υ _o+1 and i _o+1
Find the area of the triangle formed by

a _o = 1/2 (υ _o i _o+1 −υ _o+1 i _o ) ...... (1) This calculation is performed in the calculation unit 24 from n=1 to n
= 360 times using the digital voltage signal υ _o and digital current signal _{i o} stored in each memory of the storage unit 26, and then the area a _o of these triangles is calculated from n = 1 to n = 360. The total area A is determined by summing up to . Since this area A is approximate to the area of the lizard waveform,
Compare the area A ₀ of the resurge waveform R ₀ corresponding to _the allowable number of broken cores shown in FIG. An alarm signal A _S is output to 28. When area A is smaller than A ₀ ,
Returning to the beginning of the program, each memory in the storage unit 26 is cleared, zero voltage of the voltage signal υ _o is detected, and the calculation is repeated again.

In addition _, the calculated area A is compared with the areas A ₁ , A _{2 ,} . A ₂ , . . . , _Ao , the most approximate value is found, and a digital display signal _Ao corresponding to the number of broken lamps is output to the digital display 27 via the interface 23, and the current broken lamp is output. It is also possible to display the number of tube lamps.

By using the microprocessor 2, the area of the resurge waveform can be easily calculated, and the amount of core breakage of the lamp can be quickly detected.

Further, the digital voltage signal υ _o and the digital current signal i _o read into each memory of the storage unit 26 are sent via the digital-to-analog converter of the input/output interface 23 in synchronization with the sampling pulse _SP as necessary. It is also possible to draw the stored resurge waveform on the cathode ray tube by inputting it to the horizontal axis input terminal and vertical axis input terminal of the synchroscope.

Further, in the above embodiment, the area of the triangle is calculated by dividing one cycle into 360 equal parts, but the accuracy of calculating the area can be further improved by shortening the sampling period.

Furthermore, although calculations in the microprocessor 2 are performed after taking in one cycle of data, the area of the triangle can be calculated and integrated during the sampling time, thereby increasing the detection speed. can.

Further, although the above embodiments have been described in the case of a CR type CLR, it is also applicable to a thyristor type CCR.

As described above, when a part of the lamp in a series lighting circuit is broken, the current waveform is greatly distorted due to the magnetic saturation of the isolation transformer connected to the broken lamp, and the load voltage and load current are Focusing on the fact that the resurge waveform formed by the resurge waveform is deformed and the area of the resurge waveform also increases, the area of the resurge waveform is calculated with a microprocessor to detect the number of broken lamps, and the detected value is not affected by load voltage waveforms, power supply voltage fluctuations, or CCR current settings, making it possible to detect core breaks with high sensitivity. In addition, the circuit configuration is simple, does not require adjustments specific to analog circuits, and can be manufactured at low cost.

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing an example of a series lighting circuit using a general CR type CCR, Fig. 2 is a block diagram showing an embodiment of the present invention, and Figs. 3 and 4 are the same as those shown in Fig. 2. FIG. 5 is a waveform diagram illustrating the operation, and FIG. 5 is a flowchart showing the operation of FIG. 2. DESCRIPTION OF SYMBOLS 1... AC power supply, 11... CR type CCR, 12... series lighting circuit, 121... isolation transformer, 122... lamp, 2... microprocessor, 21... voltage detector, 22... current detector, 23... input/output interface Ace, 231, 232... Analog-to-digital converter, 24... Arithmetic unit, 25... Oscillator, 26... Storage unit, 27... Digital display, 28... Alarm device.

Claims (1)

[Claims] 1 In a series lighting circuit that lights a plurality of lamps from a constant current type AC power source through an isolation transformer, a circuit is provided that calculates the area of the resurge waveform of the voltage waveform and current waveform, and the area of the resurge waveform is used to calculate the A breakage detection device for a series lighting circuit, which is characterized by detecting the number of lamps.