KR100535960B1 - Power supply for traffic signal lamp - Google Patents

Abstract

The present invention relates to a power supply device for a traffic light, and minimizes an error range of a compensation method using an NTC thermistor which is used to maintain a constant amount of light according to a change in ambient temperature in a light emitting diode type traffic light employing a light emitting diode. In addition, it is possible to adjust the illuminance of the light-emitting diode type traffic light by using the incandescent light type traffic light intensity control signal of the traffic light control device to maximize the driver's safety and without the need for mechanical installation such as an optical sensor for illumination control. By using the existing traffic light control device as it is, it is possible to reduce the additional installation cost by performing the illumination control only by changing the software.

Description

POWER SUPPLY FOR TRAFFIC SIGNAL LAMP}

The present invention relates to a power supply device for a traffic light, and more particularly to a compensation method using an NTC thermistor which is used to maintain a constant amount of light that varies with atmospheric temperature change in a light emitting diode type traffic light employing a light emitting diode. The present invention relates to a power supply device for a traffic light that not only minimizes an error range but also adjusts the illuminance of a light emitting diode type traffic light by using an incandescent lamp type traffic light intensity control signal of a traffic light control device.

Incandescent bulb-type traffic lights used in the prior art not only has a significantly lower brightness than power consumption, but also has a high absolute power consumption and a short lifespan of an incandescent bulb, which adds a lot of cost to maintenance.

Therefore, recently, the power consumption is about 90% lower than the incandescent bulb, the lifespan is more than six times, and the light-emitting diode type traffic lights with greatly improved visibility have been used.

In order to drive such light emitting diode traffic lights, a power supply suitable for the light emitting diode traffic lights must be used.

These power supplies can be largely divided into linear and switching modes, but most of them use switching modes that are advanced in terms of electrical efficiency at home and abroad.

By the way, the light emitting diode traffic light has an advantage in terms of power consumption, lifespan, and visibility as described above, but has a disadvantage in that the change in brightness with temperature is very large. The temperature characteristics of the light emitting diodes vary greatly depending on the materials used. The high temperature temperature characteristics of the yellow, red, and green light emitting diodes used in traffic lights decrease the brightness by 50 to 80% at around 70 ℃. Red has a better brightness of about 30-40%, and green has a decrease in light intensity of about 20%. On the contrary, it is difficult to obtain light with uniform illumination because the amount of light is greatly increased at low temperatures.

Therefore, in order to compensate the optical characteristics of the light emitting diode sensitive to such a temperature change, a circuit compensation is required. Compensation method using NTC (Negative Temperature Coefficient of Resistor) thermistor, which is currently used, is difficult to control the intensity of light within the range of ± 20% due to the large device error range of NTC thermistor. There is a problem of poor productivity.

On the other hand, high visibility, which is one of the advantages of the LED traffic light, has a problem that may cause glare of the driver at night. Therefore, it is possible to maintain high visibility without disturbing driving by changing daytime and nighttime illumination. It is necessary to adjust the illumination.

Several methods are available for the illumination control, but the method controlled by the voltage signal of the controller is complicated because the modification of traffic light control device is inevitable and a regulator function must be added. There is a disadvantage in that the method using the optical sensor also has a problem in that the mechanical position to change the position of the optical sensor because the position of the illumination control may appear different depending on where the sensor is located.

The present invention was created to solve the above problems, and an object of the present invention is to use an NTC thermistor that is used to maintain a constant amount of light that changes according to the change in ambient temperature in a light emitting diode type traffic signal employing a light emitting diode. In addition to minimizing the error range of the compensation method, it provides a power supply device for a traffic light that can adjust the illuminance of the light emitting diode traffic light by using the incandescent lamp-type traffic light control signal of the traffic light control device.

The present invention for realizing the above object is a traffic light control device for controlling the lighting state of the traffic light and output an AC power signal having an illuminance control function, and receives an AC power signal output from the traffic light control device inside Input section for protecting circuit, full wave rectifier for full-wave rectifying AC power signal inputted through the input section, power factor compensation for the signal rectified in full-wave rectifying section and feedback output signal to adjust the oscillation frequency to adjust the output value The power factor correction unit and the voltage drop unit for dropping the power signal compensated by the power factor correction unit to the driving voltage of the LED module and the output signal dropped in the voltage drop unit are rectified and the switching frequency of the power factor correction unit is removed. By removing the ripple frequency so that it cannot be removed below the rectified frequency rectified by the full-wave rectifier A feedback unit for outputting a temperature compensation value for adjusting the oscillation frequency of the power factor correction unit according to the NTC thermistor compensation method for the rectification and ripple cancellation unit output to the LED module and the signal output from the rectification and ripple removal unit, and the temperature It is characterized by consisting of a feedback control unit for finely adjusting the temperature compensation value output from the feedback by detecting the change.

In the present invention, the noise removing unit for controlling the noise generated in the voltage drop unit is characterized in that it further comprises.

In the present invention, the AC power signal having the illuminance adjustment function of the traffic light control device is characterized in that the radio wave signal, half-wave signal or AC power signal by the phase control method.

In the present invention, the rectified frequency rectified by the full-wave rectifying unit is characterized in that less than 120Hz.

In the present invention, by adjusting the ripple removal frequency of the rectifying and the ripple removing unit is characterized in that the adjustment of the illumination range.

In the present invention, the feedback controller is characterized in that the adjustment by the PWM control or linear (linear) control by the temperature change.

According to the present invention, the feedback unit detects the temperature change in addition to the temperature compensation value compensated by the NTC thermistor, and finely adjusts the temperature compensation value through PWM control or linear control to compensate the temperature according to the temperature change. In addition to minimizing the error range of the value, the driving voltage of the LED module, which is a light emitting diode type traffic signal, is transmitted to the radio wave signal, half wave signal, or phase control signal output for the illumination control function of the incandescent lamp type traffic signal from the traffic light control device. When converting the signal to the rectifier and ripple elimination unit, only the switching frequency components above the rectified frequency are removed, and the full-wave rectified signal, half-wave rectified signal or phase controlled rectified signal is used as it is. Light-emitting die using output dimming signal It is possible to adjust the illuminance of the audible traffic lights.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the present embodiment is not intended to limit the scope of the present invention, but is presented by way of example only and the same parts as in the conventional configuration using the same reference numerals and names.

1 is a block diagram showing a power supply for traffic lights according to the present invention, Figure 2 is a circuit diagram showing a power supply device for traffic lights according to the present invention in detail.

As shown here, the traffic light control device 5 controls the lighting state of the traffic light and outputs an AC power signal for adjusting the illumination of the incandescent light by a radio wave signal, a half wave signal, or a phase control method. , An input unit 10 for receiving an AC power signal output from the traffic light control device 5 and protecting an internal circuit, and a full-wave rectifying unit 20 for full-wave rectifying the AC power signal input through the input unit 10. The power factor correction unit 30 compensates the power factor for the signal rectified by the full-wave rectifier 20 and adjusts the output value by adjusting the oscillation frequency by receiving an output signal, and the output power factor compensated by the power factor compensator 30. The voltage drop unit T1 for dropping the signal to the driving voltage of the LED module 80 and the output signal dropped from the voltage drop unit T1 are rectified and the switching frequency of the power factor correction unit 30 is removed but propagates. tablet Rectification and ripple removing unit 60 to remove the ripple frequency so as not to be removed below the rectified frequency rectified in the rectifying unit 20 and output to the LED module 80, and the signal output from the rectifying and ripple removing unit 60 The feedback unit 50 for outputting a temperature compensation value for adjusting the oscillation frequency of the power factor correction unit 30 according to the NTC thermistor compensation method, and sensing the temperature change by PWM control or linear control. It consists of a feedback control unit 70 for finely adjusting the temperature compensation value output from the feedback unit 50.

At this time, the noise removing unit 40 for controlling the noise generated in the voltage drop unit (T1) is included, the traffic light control device 5 is set to output a radio wave signal during the day and a half-wave signal at night. .

The rectified frequency rectified by the full-wave rectifying unit 20 not to be removed by the rectifying and ripple removing unit 60 is set to 120 Hz or less.

This will be described below with reference to the circuit diagram of FIG. 2.

That is, the input unit 10 receiving the AC220V power signal output from the traffic light control device 5 is an overcurrent protection device related to safety is composed of a varistor (MOV) and a fuse (F1), the external surge blocking circuit and the internal It consists of line filter (LF) and capacitors for EMI elimination and noise elimination.

Therefore, if an abnormality occurs in the internal circuit and an overcurrent flows, the fuse F1 is blown. If the input voltage rises due to any cause and becomes an overvoltage state, the impedance of the surge varistor MOV becomes low at this moment. Also, the fuse F1 is blown to protect the semiconductor circuit used after the input unit 10.

The full-wave rectifier 20 is a circuit for converting an AC voltage into a DC voltage, and full-wave rectifies the voltage input from the input unit 10 by the bridge diode D1. Therefore, when the frequency of the input voltage is a radio signal of 60 Hz, it is rectified to a frequency of 120 Hz.

In addition, the power factor correction unit 30 has a power conversion function for releasing the rectified voltage input through the full-wave rectifying unit 20 from the primary side to the secondary side of the voltage drop unit T1, and a power factor adjustment function for configuring a high power factor circuit. Do this.

That is, the operation principle of the power factor collection (PFC) circuit of the power factor correction unit 30 is the IC (U1) when the power supply (Vcc1) rectified at the Vcc (pin 8) terminal of the IC (U1) is applied through the resistors R4 and R5. MOS-FET operates by controlling the gate of MOS-FET Q1 through resistor R9 at the drive output (pin 7).

At this time, the operation state of the MOS-FET and the waveform of the output current are shown in FIG.

That is, when a current corresponding to the peak value flows, a current detection signal is supplied to the sense input (pin 4), and the MOS-FET Q1 is cut off by the internal circuit of the IC U1. In this way, when the MOS-FET is cut off, a voltage is induced to the voltage drop T1, and this power is simultaneously supplied to the Zero Current Detect Input (pin 5) and Vcc (pin 8) of the IC U1. Vcc (No.8 pin) power is continuously supplied with voltage induced from voltage drop (T1) according to ON / OFF operation of MOS-FET, and zero current is detected at Zero Current Detect Input (No.5 pin) supplied through resistor R6. Turn MOS-FET Q1 back on.

On the other hand, when the emitter output voltage of the phototransistor Q2 of the feedback unit 50 is supplied through the resistor R12 to the Voltage Feedback Input (No. 1 pin) terminal of the IC U1, the Error-Amp inside the IC U1 operates. When the output voltage is high, the switching of the MOS-FET Q1 is slowed down, that is, the frequency is lowered, and when the output voltage is low, the switching of the MOS-FET Q1 is fastened to become a constant voltage.

In order to make the voltage compared to the Sense Input (pin 4) terminal voltage on the Multiplier Input (pin 3) terminal of the IC (U1), supply power by dividing the resistors R1, R2 and R3 to the internal circuit of the IC (U1). The peak current value of the inductor is sensed to turn off the MOS-FET Q1.

As this phenomenon is repeated, an input waveform as shown in FIG. 3 is formed and an output is controlled.

That is, the pulsation waveform rectified by the full-wave rectifying unit 20 detects the inductor current over the entire period at a frequency of several tens of kHz or more as shown in FIG. 3, and turns on the MOS-FET Q1 at the point where it becomes zero current, and the current is applied to the input voltage. By switching off when the proportional maximum value is reached, the input current waveform becomes a pure sine wave and becomes in phase with the voltage, thus improving the power factor.

On the other hand, the feedback unit 50 is provided with an overcurrent prevention circuit and an output short circuit prevention circuit from above to breakdown from the cathode to the anode when the gate of the shunt regulator U2 exceeds 2.5V. ) And below 2.5V, which is cut off by the resistors R19, R20 and thermistors NTC1 and NTC2.

As described above, temperature compensation is primarily performed through the feedback unit 50 by the NTC thermistor method, and precise control of the region by the device error range of the NTC thermistor in the feedback unit 50 through the feedback control unit 70 is performed. By controlling the resistance value biasing the error range of the NTC thermistor according to the temperature change by using the OP amplifier to precisely control the output value output to the LED module 80 by precisely controlling in a wide range by PWM control or linear control. Precise and easy adjustment

Therefore, it is possible to precisely adjust the output value to obtain a constant amount of light in the LED module 80 that the brightness changes even ± 50% or more according to the temperature change.

In addition, the power factor correction unit 30 uses the power of mixed 120Hz ripple rectified 60Hz in the full-wave rectifying unit 20 as it is and outputs the output by switching. Therefore, the signal dropped and output from the voltage drop unit T1 is rectified through the diode D16 of the rectifying and ripple removing unit 60 to remove the ripple voltage by the capacitor C13.

At this time, the capacitance of the capacitor (C13) is determined by the capacity to remove only the switching frequency by determining its capacity around 120Hz. So, if you use a capacity that can hardly remove 120Hz, the output is like a low voltage 120Hz waveform rectified to 60Hz.

In this way, by installing an optical sensor to adjust the illuminance on the outside, the capacity of the capacitor (C13) for removing the ripple is insufficient without using a method that must inevitably accompany the structural change of the traffic signal, thereby preventing the ripple from being removed. Even if the illuminance is adjusted, the entire circuit operates stably, so that it is possible to have an illuminance control function by simply using an AC power signal for illuminance control of an incandescent light signal output from a traffic light control device.

The above operation will be described with reference to a waveform diagram illustrating a process of converting an input signal shown in FIGS. 4 and 5 into an output signal.

First, FIG. 4 is a view showing waveforms when a radio wave signal is output from the traffic light control device, and FIG. 5 is a view showing waveforms when a half wave signal is output from the traffic light control device.

In the case of using the insufficient capacity of the capacitor C13, when the half wave signal is input when the final output current of FIGS. 4 and 5 is viewed, only half of the first set current is output as compared with the case where the radio wave signal is input, By outputting only half, the dimming effect can be obtained.

In addition, by adjusting the capacitance of the capacitor C13 of the rectifying and ripple removing unit 60, the ripple voltage may be slightly reduced to adjust the setting of low illuminance at a value between 50% and 100%.

On the other hand, even when the AC power signal by the phase control method is output from the traffic light control device as shown in Figure 6 is output through the process as shown in Figures 4 to 5, when the illumination control by the phase control method is wider Illumination control of the range is possible.

As such, the dimming control is possible in a wide range by using the dimming control signal used to apply the incandescent lamp type traffic signal in the currently used traffic light control device 5 as it is to the LED traffic light. Noise, such as EMI, that may be generated by adjusting the median value of the noise is blocked by a line filter of the input unit 10.

Experimental Example

The results of testing the temperature compensation and illuminance control characteristics of six traffic and pedestrian traffic lights using the power supply device for traffic lights according to the present invention are shown in Table 1.

Vf of the light emitting diode substrate used was between 15 and 25V, and If of the light emitting diode used was 30mA (Vf = 2.0V (red / yellow), Vf = 3.5V (blue)). The maximum current flowing through each LED during temperature compensation was set to a maximum at less than 85% of the If value, and the temperature characteristic test was performed at a rate of about 0.5 ° C / min over about 8 hours from -30 ° C to 70 ° C. The temperature is raised and measured at six or more points.

The reference light quantity was measured at room temperature (25 ° C) and was measured after 20 minutes of retention time at each measurement point. The dimming test was attempted using the same half-wave signal for dimming of a general incandescent bulb type traffic light in a traffic light control device. At this time, the pedestrian traffic light did not need illumination control, so the illumination control experiment was conducted only for the traffic light.

division yellow Red green Green arrow Red pedestrian Green pedestrian Brightness 500cd 450cd 450cd 6,000cd / m2 3,500 cd / m2 2,500 cd / m2 Output current (mA) 220 190 290 125 65 195 Light change amount (%) maximum +6 +3 +1 0 +1 +1 at least -8 -4 -5 -4 -6 -5 Dimming Level (%) 55 55 55 55 - -

As can be seen in Table 1, it can be seen that according to the power supply device for traffic lights according to the present invention can obtain a constant light output for a wide temperature range. In addition, in the illumination control function, the output signal from the traffic light control device shows that the light quantity can be stably reduced to about 55% of the weekly maximum value.

As such, the light quantity of the light emitting diode can be adjusted within 10% according to the temperature change, and the illumination at night can be reduced to 50 ~ 60% to maximize the driver's safety.

As described above, the present invention not only minimizes the error range of the compensation method using the NTC thermistor which is used to maintain a constant amount of light that changes according to atmospheric temperature in the light emitting diode type traffic signal employing the light emitting diode, and also controls the traffic light. By using the incandescent lamp-type traffic light dimming control signal of the device can adjust the illuminance of the LED-type traffic light has the advantage that can maximize the driver's safety.

In addition, by using the existing traffic light control device as it is without the mechanical installation of the light sensor for the illumination control, there is an advantage to reduce the additional installation cost by performing the illumination control only by changing the software.

1 is a block diagram schematically showing a power supply device for a traffic light according to the present invention.

2 is a circuit diagram illustrating in detail a power supply device for a traffic light according to the present invention.

3 is a view showing the output waveform of the power factor correction unit of the power supply device for traffic lights according to the present invention.

4 and 5 are views illustrating waveforms in a process of converting an input signal into an output signal in a traffic light power supply device according to the present invention.

6 is a view showing an illumination control signal according to the phase control method in the power supply for traffic lights according to the present invention.

   -Explanation of symbols for the main parts of the drawings-

5: traffic light control device 10: input unit

20: full wave rectifier 30: power factor correction unit

40: noise removing unit 50: feedback unit

60: rectification and ripple removing unit 70: feedback control unit

80: LED module T1: voltage drop

Claims (6)

A traffic light control device for controlling the lighting state of the traffic light and outputting an AC power signal having an illuminance control function; An input unit for receiving an AC power signal output from the traffic light control device and protecting an internal circuit; A full-wave rectifying unit for full-wave rectifying the AC power signal inputted through the input unit; A power factor correction unit for compensating a power factor for the signal rectified by the full wave rectifier and adjusting an output value by receiving an output signal and adjusting an oscillation frequency; A voltage drop unit for dropping the power signal compensated by the power factor correction unit to a driving voltage of the LED module; Rectification and ripple agent for rectifying the output signal dropped from the voltage drop and removing the switching frequency of the power factor correction unit to remove the ripple frequency so as not to be removed below the rectified frequency rectified in the full-wave rectifier. With rejection, A feedback unit for outputting a temperature compensation value for adjusting the oscillation frequency of the power factor correction unit according to an NTC thermistor compensation scheme for the signal output from the rectification and ripple cancellation unit; Feedback control unit for finely adjusting the temperature compensation value output from the feedback by detecting the temperature change Power supply for traffic lights, characterized in that consisting of. The power supply device for a traffic light of claim 1, further comprising a noise removing unit for controlling noise generated by the voltage drop unit. The power supply device for a traffic light according to claim 1, wherein the AC power signal having the illuminance control function of the traffic light control device is an AC power signal based on a radio wave signal, a half wave signal, or a phase control method. The power supply device for a traffic light of claim 1, wherein the rectified frequency rectified by the full wave rectifying unit is 120 Hz or less. The power supply device for a traffic light according to claim 1, wherein the illuminance control range can be adjusted by adjusting the ripple removing frequency of the rectifying and ripple removing unit. The power supply device for a traffic light of claim 1, wherein the feedback control unit is controlled by PWM control or linear control due to temperature change.