RU2378706C1 - Device for controlling ultra-bright light-emitting diodes in active light signal heads - Google Patents

Abstract

FIELD: physics; control.

SUBSTANCE: invention relates to the technology of controlling traffic lights. The control device has a dc power supply unit, connected through a controller to a block of light sources consisting of series-parallel-connected ultra-bright light-emitting diodes, and a control unit. The controller is made in form of a unit of a double-channel microprocessor controller and includes two independent sets of microcontrollers with a function for mutual testing and comparing received data, as well as separate sets of crystal oscillators for each microcontroller. The block of light sources includes a circuit for separate blocking broken light-emitting diodes and a double-channel circuit for controlling faulty light-emitting diodes through optocouplers which is connected to two galvanically isolated channels of the microprocessor controller. The control unit is made in form of a unit for safe control and switching and includes a physical line breaking circuit, a circuit for controlling diode bridges with an analogue-to-digital converter and a double-cascade input signal analysis circuit. The power supply unit includes an overvoltage protection device, two rectifiers, a filter, a device for switching modes of the traffic light signal ("day", "night", "double voltage reduction") with stabilised supply current for light-emitting diodes, two power supplies which provide stabilised power for two microprocessor channels of the unit of the microprocessor controller and the current stabiliser.

EFFECT: device is characterised by highly reliable operation, technological effectiveness and safe use.

1 dwg

Description

Controller device for controlling superbright LEDs in active traffic light heads.

The claimed technical solution relates to the field of microelectronics and can be used in traffic light heads of traffic control systems.

Known technical solution for the patent No. 2248107 from 2000.11.03, HB 37/02, JP,

LED tube system has:

a unit for connecting to an AC power source, a converter for forming a DC power source, and an LED group consisting of a plurality of LEDs.

The LED group is equipped with a service life pre-notification unit, including counting means for measuring the power supply period based on the frequency of the AC power source, integrating means for supplying power measured by the counting means, and storing the integrated value in a non-volatile memory and means for supply mode control power supplies to control the LEDs in various modes, including normal lighting.

The preliminary message block is designed to integrate the period of power supply for issuing a preliminary message indicating the approaching end of the service life.

The advantage is the presence of a preliminary service life block indicating the approaching end of the service life.

However, the system does not provide control over the health of circuit elements during device operation and the system locks in case of violations of the power supply mode, which excludes its use in traffic control devices.

The closest analogue is the technical solution according to patent EP 1777533 from 10.21.2005, G01R 31/26, HB05/08, DE.

A control device for a group of electrical units, preferably a group of high-brightness light emitting diodes (LEDs), connected in series and controlled by direct current,

including:

locking means, evaluation unit,

signaling device

including:

a group of lighting devices, in particular light emitting diodes (LEDs) of high brightness, connected in series; DC source, control device, control unit, specific mirror / lens system, signal device is used as a railway signal lamp.

The advantage is the presence of an individual lockout of burnt out LEDs, which allows using the device in traffic control systems in vehicles.

However, the device does not provide dynamic control of the blocking circuit elements and assumes the accumulation and masking of failures, reducing the time between failures in critical traffic control devices.

The purpose of the development of the proposed technical solution is to increase the reliability of devices to a failure rate of 10 ^-10 hour ^-1 , the safety of their use, the adaptability of use in relay or microprocessor-based traffic control systems.

The goal is achieved as follows.

A controller device for controlling superbright LEDs in active traffic light heads contains a blocking means, an evaluation unit, a signal device including high-brightness light emitting diodes (LEDs) connected in series in DC controlled electric currents, and the device is made of functional blocks:

- a block of light sources (LSI), containing:

- superbright LEDs connected in series-parallel,

- scheme for individual blocking of dangling LEDs,

- a two-channel control circuit of failed LEDs through optocouplers connected to two BMK galvanically isolated channels,

- block two-channel microprocessor controller (BMK), containing:

- two independent sets of microcontrollers with the function of mutual testing and comparison of the received data,

- individual sets of crystal oscillators for each microcontroller,

- safe control and shutdown unit (BBCO), containing:

- a circuit for the physical opening of the line,

consisting of four independent sets, two for each power line for each microcontroller,

- a control circuit of diode bridges containing;

- analog-to-digital converter,

- an input signal analysis circuit consisting of two stages:

- triggering, generating a signal of the "saw" type with stable time and amplitude characteristics;

- adder, carrying out the addition of signals from the starting stage and the rectified input voltage,

- power supply unit (PSU) containing:

- surge protection device,

- two rectifiers, filter,

- a device for switching on traffic light signal modes (“day”, “night”, “SDS”) with a stabilized LED power supply current,

- two power sources, providing a stabilized power supply of two microprocessor channels BMK,

- current stabilizers connected in series-parallel, which are controlled by a microprocessor controller.

In the presented drawing:

Figure 1 is a block diagram of a device where

1 - control device

2 - Power supply unit (PSU),

3 - Block two-channel microprocessor controller (BMK),

4 - Block light sources (LSI),

5 - Block of safe control and shutdown (BBKO).

Description of the circuit diagrams and the principle of operation of the blocks.

Block of light sources (LSI).

The light source unit consists of 12 LEDs, divided into four groups. Each group consists of 3 LEDs connected in series. The anodes of each group of LEDs are connected to separate zener diodes, and the cathodes are connected to a common PSU bus. Depending on the required mode of switching on the traffic light signal (“day”, “night”, “SDS”), the BMK connects the current-stabilized voltage to the required number of LEDs in each group. Each LED included in the Light Source Block is connected via optocouplers to two BMK galvanically isolated channels to control the number of failed LEDs, as well as to an individual blocking circuit for dangling LEDs. The luminosity of each LED and their number, included in each mode ("day", "night", "SDS"), are selected in such a way that the output light flux of the traffic light signal meets the requirements of the technical specifications for each mode of operation of the traffic light signal. Technologically, the LSI is made on a separate printed circuit board, on which there are 12 LEDs and a connector for connecting to the BMK board. The principle of operation of the block of light sources.

When the traffic light signal is turned on by the control unit, one of the 6V, 9V, or 12V voltage is supplied to the PSU input, depending on the mode of switching on the traffic light signal (“day”, “night”, “SDS”), according to which the BMK determines in which mode (“ day "," night "," SDS ") should work LED. Consider turning on the LED in day mode. If the BMK has determined that at the given moment the traffic signal should work in the “day” mode (12 V is supplied to the power supply input), it connects the corresponding four current stabilizers through which the supply voltage (current stabilized) is supplied to the four groups of LEDs, where each the group consists of three LEDs, that is, 12 LEDs are simultaneously turned on, which ensures radiation of the light flux corresponding to the “day” mode. The number of simultaneously turned on LEDs and the current flowing through them are selected with the condition that the output light output of the traffic light signal should exceed approximately twice the minimum normalized value of the output light output defined in the TOR for the “day” mode. Consider turning on the LED in night mode. If the BMK determines that at a given moment the traffic signal should work in the night mode (9V is supplied to the PSU input), it connects the corresponding four current stabilizers through which the supply voltage (current stabilized) is supplied to the four groups of LEDs, where each the group consists of two LEDs, that is, 8 LEDs are simultaneously turned on, which provides radiation of the light flux corresponding to the "night" mode. The number of simultaneously turned on LEDs and the current flowing through them are selected under the condition that the output light flux of the traffic light signal should be approximately two times the minimum normalized value of the output light flux defined in the TOR for the night mode. Consider the inclusion of LEDs in the "SDS" mode. If the BMK determines that at a given moment the traffic signal should work in the “SDS” mode (6V is supplied to the power supply input), it connects the corresponding three current stabilizers through which the supply voltage (current stabilized) is supplied to the three groups of LEDs, where each the group consists of one LED, that is, 3 LEDs are simultaneously turned on, which ensures radiation of the light flux corresponding to the "SDS" mode. The number of simultaneously turned on LEDs and the current flowing through them are selected with the condition that the output light flux of the traffic light signal should be at the level of the upper value, that is, 8% of the minimum normalized value of the output light flux defined in the statement of work for the "SDS" mode. If the control unit turns on the night mode during the operation of the traffic signal in the day mode (9V is supplied to the PSU input), the BMC will turn off 12 LEDs operating in the day mode and turn on 8 LEDs operating in the night mode. If the control unit switches on the "SDS" mode during the period of the traffic signal in the "night" mode (6V is input to the power supply unit), the BMC will turn off 8 LEDs operating in the "night" mode and turn on 3 LEDs operating in the "SDS" mode. Switching of the LED operating modes can be carried out at any time based on the supply voltage coming from the control devices. To monitor the health of the LEDs are used:

- two optocouplers connected in parallel with the LED (during the breakdown of the LED, its resistance tends to zero, therefore, the electric current goes through the circuit with a lower resistance, the optocouplers are closed);

- two optocouplers connected in series with the LED (when the LED breaks, its resistance tends to infinity, therefore, the electric current goes through the circuit with a lower resistance - the zener diode opens, the optocouplers close).

Due to the fact that in operating conditions the signal may be in the on state for a long time, it becomes necessary to monitor the health of circuit elements. Control is carried out by the method of short-term removal of the supply voltage (millisecond) with an interval of one minute. When removing power, all elements of the circuit must change their state to the opposite, otherwise a conclusion is made about the malfunction. In case of a malfunction of the LED or its control elements, it is marked as malfunctioning.

Block microprocessor controller (BMK). The microprocessor controller unit consists of two software and hardware independent, galvanically isolated channels, built on separate microprocessors with installed software that implements monitoring and control algorithms for the BSSS-MK operating modes. Power supply unit (PSU).

PSU is connected to the power line from control devices. To protect the circuit in the input stage, the following devices are installed: surge protection devices, two rectifiers, filters, a device for stabilizing the supply voltage. Each microprocessor is powered by an individual kit using a DC-DC converter. A malfunction of any of the microcontroller’s batteries leads to its shutdown, which is recorded during interprocessor exchange. The voltage supply to the LEDs is carried out using a circuit with a stabilized supply current. A transformer isolation is also used to protect against a transistor switch malfunction. For each of the glow modes, an individual power kit is used. The difference between the sets is the number of current stabilizers, for the “day” and “night” modes - four, for the “SDS” - three. Current stabilizers are used to supply a current-stabilized signal to successive chains of LEDs. The transformer is used for galvanic isolation and the formation of control voltage. An electronic key is included in the primary winding circuit, forming an alternating voltage. In the event of a breakdown or a break in the key in the secondary winding, there will be no signal, therefore, there will be no power to the LEDs, which is fixed by the LED health monitoring circuit. In the event of a power failure on the LED, there will be no voltage, which is recorded by microprocessors.

Safe Control and Shutdown Unit (BBCO).

BBCO consists of three parts:

Scheme of physical disconnection of the line.

The circuit consists of four independent sets, two for each power line for each microprocessor. The circuit consists of a transformer, current stabilizers and diodes. The secondary low-resistance winding is connected in series to the power circuit. When the circuit is off, there is no voltage in the secondary winding and, due to the low resistance, does not create obstacles to the passage of the control voltage. After making a decision about the need to simulate burnout of the thread, the controller sends antiphase pulses (IMP) and a constant signal (POST). When the key is switched by a signal (KL), a short-term pulse is generated in the power circuit. This current pulse exceeds the fuse rating by five times, which causes it to blow. To control the serviceability of this circuit, the IMP frequency is increased and a low denomination pulse enters the line, and it is fixed by the signal analysis circuit. Checking each set of schemes is carried out individually.

Control circuit of diode bridges.

This circuit is based on the principle of controlling the supply voltage at the rectifier output using an ADC. The circuit is based on monitoring the level of voltage coming from the control devices. It performs the function of converting the voltage coming from the control devices into a voltage that meets the voltage level of the analog-digital input of microprocessors, as well as the function of galvanic isolation of the controlled electrical circuits from the electrical circuits of the microprocessor channels. If the shoulder of the diode bridge fails, the level of the variable component will increase and this situation is recorded using the built-in ADC of the microcontroller. Monitoring is carried out according to the scheme two of two, for each microcontroller an independent channel is organized and the result is compared. The resistor sets the sensitivity of the circuit.

Input signal analysis circuit.

The control circuit of analog signals performs the function of converting analog signals to discrete signals that satisfy the requirements of the input microprocessor circuits to control the voltage level coming from the control devices. Functionally, the circuit is built on multivibrators. An individual kit is made for each microprocessor. The circuit consists of two stages:

- the first stage generates a “saw” type signal with stable time and amplitude characteristics;

- the second stage performs the addition of signals from the first stage and the rectified input voltage. As a result, pulses of various lengths are formed at the output of the circuit, depending on the level of the input voltage. These pulses are fed to the digital input of the microprocessors, where the duration is measured, after comparing the results, a decision is made on the signal glow mode. If one of the sets fails, at the stage of comparing the obtained results, a discrepancy is revealed

The device operates as follows. From control device 1, a signal arrives:

Signal head glow modes AC voltage, V DC voltage, V Day 10-15 10-15 Night 8-10 8-10 SDS 4-7.5 4-7.5 Thread Integrity Cold Control 0.5-3 0.5-3

The signal may be continuous and blinking.

1. The system is operational.

The signal enters block 2 (PSU). After passing the anti-jamming devices and filters, it gets on two power sources that provide stabilized power to the two microprocessor channels of unit 3 (BMK) and two channels of unit 5 (BBKO), a safe shutdown circuit in case of failures.

Next, block 3 (BMK) performs testing of hardware and software, block 2 (PSU) and light emitting diodes (LEDs), transmits signals for monitoring the operability of hardware and software of processors to block 5 (LBCO), monitors the voltage level from external devices, and the inclusion of the traffic signal "day", "night", "SDS".

Next, block 4 (LSI) emits a luminous flux of a set color and a given light intensity set by block 3 (BMC). The color of the light flux is determined by the type of installed light emitting diodes (LEDs), which provide five primary colors of the signals: red, yellow, green, blue, moon white. The luminous intensity of the signal is determined by the number of light emitting diodes (LEDs) simultaneously switched on in each mode (“day”, “night”, “SDS”) and the current flowing through them. Modes of inclusion of the signal ("day", "night", "SDS") are set by unit 3 (BMK) depending on the voltage level coming from the devices. Block 4 (LSI) is monitored and controlled by block 3 (BMC).

2. The system is malfunctioning.

If a different type of internal malfunction is detected, block 3 (BMC) makes a decision to switch to a safe, irrevocable state by disconnecting the device from power using block 5 (LSC).

Functioning algorithm

The input voltage in the power line (main or backup).

1. The input signal is rectified, filtered and turns on the microcontrollers.

2. The first test of microcontroller resources. In the event of a malfunction, a physical disconnection from the power line occurs.

3. Analysis of the input signal and making a decision on the need to turn on the LEDs (control signal or interference). The choice of the glow mode: "day"; "night"; "SDS".

4. Turning on the light sources. The start of the countdown.

5. Monitoring the health of the LEDs.

6. Monitoring the health of the physical disconnect circuit from the line.

7. Control circuit health diode bridges.

8. Analysis of the signal glow time (continuously burning or blinking signal - one second glow, half a second pause). If continuously burning - continuation of the algorithm. If blinking, go to the beginning of the algorithm.

9. Short-term shutdown of LEDs to control LED control circuits.

10. The second test of the resources of microcontrollers. In the event of a malfunction, physical disconnection from the power line.

11. Repeated implementation of paragraphs 4-11.

12. Turning off the signal power by the control devices.

If 30% of the LEDs fail, the main signal power line is turned off. Information about failed LEDs is recorded and stored in non-volatile memory of microcontrollers. In case of malfunctions of the remaining elements of the circuit, a physical disconnection from the power line occurs.

The claimed technical solution is industrially applicable and does not present difficulties for the current level of production.

The claimed technical solution is developed, tested and passed an examination for safety at the testing center of railway automation-telemechanics of St. Petersburg State University of Railway Engineering.

In operating conditions, the signal can be in the on state for a long time, it becomes necessary to monitor the health of circuit elements. Control is carried out by the method of short-term removal of the supply voltage with an interval of one minute. The ability to control the health of circuit elements increases the reliability of the device.

The safety of the device is as follows. In the event of a breakdown or a break in the key in the secondary winding, there will be no signal, therefore, there will be no power to the LEDs, which is fixed by the LED health monitoring circuit. In the event of a power failure on the LED, there will be no voltage, which is recorded by microprocessors.

By reducing the weight and dimensions of the device, the processability of application in relay or microprocessor-based traffic control systems is increased.

Claims (1)

A controller device for controlling superbright LEDs in active traffic light heads, comprising a direct current power supply unit connected through a controller to a light source unit consisting of superbright LEDs connected in series and parallel, and a control unit, characterized in that
the controller is made in the form of a block of a two-channel microprocessor controller and includes two independent sets of microcontrollers with the function of mutual testing and comparison of the received data, as well as individual sets of crystal oscillators for each microcontroller,
the light source unit includes an individual blocking circuit for dangling LEDs and a two-channel circuit for monitoring failed LEDs through optocouplers connected to two galvanically isolated channels of the microprocessor controller,
the control unit is made in the form of a safe control and shutdown unit and includes a physical line disconnection circuit consisting of four independent sets, two for each power line for each microcontroller, a diode bridge control circuit with an analog-to-digital converter, a two-stage input signal analysis circuit consisting of a triggering stage generating a “saw” signal with stable temporal and amplitude characteristics, and an adder performing the addition of signals from the triggering scad and rectified input voltage,
the power supply unit includes an overvoltage protection device, two rectifiers, a filter, a device for switching on traffic light signal modes ("day", "night", "double voltage reduction") with a stabilized LED power supply current, two power supplies that provide stabilized power to two microprocessor channels of the microprocessor controller unit, current stabilizers connected in series-parallel, which are controlled by the microprocessor controller unit.

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