LED lamp tube control method, system and device
Technical Field
The invention relates to the technical field of LEDs, in particular to a method, a system and a device for controlling an LED lamp tube.
Background
The current LED light emitting chips are mature, and the downstream lamps can be various in types, and all flowers are in the same place. Before a large technical background is discussed, from the perspective of energy conservation and emission reduction, the power factor of an electrical appliance is required to be as high as possible (more than 0.9), an LED lamp tube is generally 18w, although the single wattage is not large, the application scene is generally used on a large scale, and more than 3000 LEDs are frequently installed in a 6000 square market; therefore, the power factor has great influence on the loss caused by current work, so that the index of the power factor (PF value) has great significance in the energy conservation and emission reduction industry. On the other hand, from the viewpoint of eye health, consumers demand lamps not to have low-frequency flicker, otherwise, the lamps are easy to cause eye fatigue, and the requirements are strict especially in some places such as classrooms, office buildings and the like.
However, the existing LED lamp tube has high power factor but low-frequency flicker; or the stroboscopic phenomenon is avoided, but the power factor is not high (generally below 0.65), and the requirement of a user cannot be met.
Disclosure of Invention
In order to solve the above technical problems, an object of the present invention is to provide a method, a system and a device for controlling an LED lamp with high power factor, which can reduce stroboflash.
The technical scheme adopted by the invention is as follows:
a control method of an LED lamp tube comprises the following steps:
generating a driving signal to supply constant current to the LED lamp tube;
and detecting the voltage value of a lamp tube capacitor connected with the LED lamp tube in parallel in real time, and feeding back and controlling a driving signal to slowly change according to the voltage value of the lamp tube capacitor.
As a further improvement of the LED lamp control method, the method further comprises the following steps:
in the gear shifting process, the voltage value of a lamp tube capacitor connected with the LED lamp tube in parallel is controlled to be quickly increased to the conduction voltage threshold value of the LED lamp tube when the power is on, and then the voltage value of the lamp tube capacitor is controlled to be slowly increased to the voltage stabilizing value of the LED lamp tube; and when the LED lamp tube is turned off, the voltage value of the lamp tube capacitor connected with the LED lamp tube in parallel is controlled to quickly drop to the conducting voltage threshold value of the LED lamp tube, and then the voltage value of the lamp tube capacitor is controlled to slowly drop.
As a further improvement of the LED lamp control method, the step of performing constant current power supply on the LED lamp by generating a driving signal specifically includes:
generating a sawtooth wave signal and generating an adjustable reference signal according to a feedback PWM signal;
and comparing the sawtooth wave signal with the adjustable reference signal to generate a driving signal and supplying constant current to the LED lamp tube.
As a further improvement of the LED lamp control method, the step of detecting the voltage value of the lamp capacitor connected in parallel with the LED lamp in real time and feeding back the control driving signal to change slowly according to the voltage value of the lamp capacitor specifically includes:
if the voltage value of a lamp tube capacitor connected with the LED lamp tube in parallel is detected in real time to be within a preset voltage range, keeping the current driving signal output;
if the voltage value of the lamp tube capacitor connected with the LED lamp tube in parallel is detected in real time to exceed the preset voltage range, the duty ratio of the driving signal is fed back and controlled to be slowly reduced;
and if the voltage value of the lamp tube capacitor connected with the LED lamp tube in parallel falls out of the preset voltage range in real time, the duty ratio of the feedback control driving signal is slowly increased.
As a further improvement of the LED lamp control method, the duty cycle of the feedback control driving signal is slowly reduced, which specifically includes:
the duty cycle of the feedback control drive signal is slowly decreased with a decrement slope of less than 1%/ms.
As a further improvement of the LED lamp control method, the duty ratio of the feedback control driving signal is slowly increased, which specifically includes:
the duty cycle of the feedback control drive signal is slowly increased with an incremental slope of less than 1%/ms.
The other technical scheme adopted by the invention is as follows:
an LED tube control system comprising:
the power supply unit is used for generating a driving signal to supply constant current to the LED lamp tube;
and the feedback unit is used for detecting the voltage value of the lamp tube capacitor connected with the LED lamp tube in parallel in real time and controlling the driving signal to slowly change according to the voltage value feedback of the lamp tube capacitor.
As a further improvement of the LED tube control system, the power supply unit specifically includes:
the signal generating unit is used for generating a sawtooth wave signal and generating an adjustable reference signal according to the fed back PWM signal;
and the comparison unit is used for comparing the sawtooth wave signal with the adjustable reference signal to generate a driving signal and supplying constant current to the LED lamp tube.
As a further improvement of the LED tube control system, the feedback unit specifically includes:
the first feedback output unit is used for keeping the current driving signal output if the voltage value of the lamp tube capacitor connected with the LED lamp tube in parallel is detected in real time to be within a preset voltage range;
the second feedback output unit is used for feeding back and controlling the duty ratio of the driving signal to slowly reduce if the voltage value of the lamp tube capacitor connected with the LED lamp tube in parallel is detected in real time to exceed a preset voltage range;
and the third feedback output unit is used for feeding back and controlling the duty ratio of the driving signal to slowly increase if the voltage value of the lamp tube capacitor connected with the LED lamp tube in parallel falls out of a preset voltage range in real time.
The invention adopts another technical scheme that:
an LED lamp tube control device comprises:
a memory for storing a program;
and the processor is used for executing the program, and the program enables the processor to execute the LED lamp tube control method.
The invention has the beneficial effects that:
the LED lamp tube control method, the system and the device can perform feedback control on the constant current power supply of the LED lamp tube by monitoring the voltage value in real time, so that the driving signal is slowly changed, the LED lamp tube can not generate low-frequency flicker while having a high power factor, and can realize a gear shifting function when being restarted within 5 seconds after the power supply is turned off, and the control can be realized without adopting an integrated IC (integrated Circuit), thereby effectively reducing the production cost.
Drawings
FIG. 1 is a flow chart illustrating steps of a method for controlling an LED lamp according to the present invention;
fig. 2 is a block diagram of an LED tube control system according to the present invention.
Detailed Description
The following further describes embodiments of the present invention with reference to the accompanying drawings:
referring to fig. 1, the LED lamp control method of the present invention includes the following steps:
generating a driving signal to supply constant current to the LED lamp tube;
and detecting the voltage value of a lamp tube capacitor connected with the LED lamp tube in parallel in real time, and feeding back and controlling a driving signal to slowly change according to the voltage value of the lamp tube capacitor.
Further as a preferred embodiment, the method further comprises the following steps:
in the gear shifting process, the voltage value of a lamp tube capacitor connected with the LED lamp tube in parallel is controlled to be quickly increased to the conduction voltage threshold value of the LED lamp tube when the power is on, and then the voltage value of the lamp tube capacitor is controlled to be slowly increased to the voltage stabilizing value of the LED lamp tube; and when the LED lamp tube is turned off, the voltage value of the lamp tube capacitor connected with the LED lamp tube in parallel is controlled to quickly drop to the conducting voltage threshold value of the LED lamp tube, and then the voltage value of the lamp tube capacitor is controlled to slowly drop. Therefore, the memory unit in the support system records the current state (0 or 1) for not less than 5 seconds, so that when a signal for restarting the switch is received within 5 seconds, the residual electric quantity can drive the control system to perform logical inversion to achieve the purpose of gear shifting.
In this embodiment, taking 7 parallel 15 strings of LED arrays as an example, the turn-on voltage threshold is 38V, the regulated voltage value is 45V, and the voltage of the lamp capacitor connected in parallel with the LED lamp is either higher than 38V or lower than that, that is, the LED lamp is turned on until the voltage reaches this voltage. Because the shifting action of the LED lamp tube is implemented by switching on and off the power supply through a switch, in the process, the power is quickly raised to 38V when the power is switched on, and then the power slowly rises to 45V; when the lamp is turned off, the voltage drops from 45V to less than 38V, when the lamp is turned off, the voltage value of the lamp tube capacitor drops slowly after the voltage value drops to 38V, and the redundant charges are absorbed completely after more than 5 seconds. In this way, the power supply is maintained for a longer time after the light is turned off, and there is a great advantage in maintaining the shift information. Even if some people with relatively slow movement use the gear shifting function, the rhythm cannot be followed in the process of switching on and off the switch.
As a further preferred embodiment, the constant-current power supply for the LED lamp by generating the driving signal specifically includes:
generating a sawtooth wave signal and generating an adjustable reference signal according to a feedback PWM signal;
and comparing the sawtooth wave signal with the adjustable reference signal to generate a driving signal and supplying constant current to the LED lamp tube.
As a preferred embodiment, the detecting the voltage value of the lamp capacitor connected in parallel with the LED lamp in real time, and feeding back the control driving signal to change slowly according to the voltage value of the lamp capacitor, specifically includes:
if the voltage value of a lamp tube capacitor connected with the LED lamp tube in parallel is detected in real time to be within a preset voltage range, keeping the current driving signal output;
if the voltage value of the lamp tube capacitor connected with the LED lamp tube in parallel is detected in real time to exceed the preset voltage range, the duty ratio of the driving signal is fed back and controlled to be slowly reduced;
and if the voltage value of the lamp tube capacitor connected with the LED lamp tube in parallel falls out of the preset voltage range in real time, the duty ratio of the feedback control driving signal is slowly increased.
Further as a preferred embodiment, the duty ratio of the feedback control driving signal is slowly decreased, and specifically:
the duty cycle of the feedback control drive signal is slowly decreased with a decrement slope of less than 1%/ms.
As a preferred embodiment, the duty ratio of the feedback control driving signal is slowly increased, and specifically includes:
the duty cycle of the feedback control drive signal is slowly increased with an incremental slope of less than 1%/ms.
The specific embodiment of the invention is as follows:
s1, generating a sawtooth wave signal and generating an adjustable reference signal according to the fed back PWM signal;
and S2, comparing the sawtooth wave signal with the adjustable reference signal to generate a driving signal and supplying constant current to the LED lamp tube.
S3, detecting the voltage value of a lamp tube capacitor connected with the LED lamp tube in parallel in real time, and if the voltage value is within a preset voltage range, keeping the current driving signal output; if the voltage value exceeds the preset voltage range, the duty ratio of the feedback control driving signal is slowly reduced, so that the inflow of the lamp tube capacitor is reduced; if the voltage value falls out of the preset voltage range, the duty ratio of the feedback control driving signal is slowly increased, so that the inflow of the lamp capacitor is increased.
In the embodiment, the PF value is ensured to be larger than 0.95 while the LED lamp body stably works.
Referring to fig. 2, the LED lamp control system of the present invention includes:
the power supply unit is used for generating a driving signal to supply constant current to the LED lamp tube;
and the feedback unit is used for detecting the voltage value of the lamp tube capacitor connected with the LED lamp tube in parallel in real time and controlling the driving signal to slowly change according to the voltage value feedback of the lamp tube capacitor.
As a preferred embodiment, the power supply unit specifically includes:
the signal generating unit is used for generating a sawtooth wave signal and generating an adjustable reference signal according to the fed back PWM signal;
and the comparison unit is used for comparing the sawtooth wave signal with the adjustable reference signal to generate a driving signal and supplying constant current to the LED lamp tube.
Further as a preferred embodiment, the feedback unit specifically includes:
the first feedback output unit is used for keeping the current driving signal output if the voltage value of the lamp tube capacitor connected with the LED lamp tube in parallel is detected in real time to be within a preset voltage range;
the second feedback output unit is used for feeding back and controlling the duty ratio of the driving signal to slowly reduce if the voltage value of the lamp tube capacitor connected with the LED lamp tube in parallel is detected in real time to exceed a preset voltage range;
and the third feedback output unit is used for feeding back and controlling the duty ratio of the driving signal to slowly increase if the voltage value of the lamp tube capacitor connected with the LED lamp tube in parallel falls out of a preset voltage range in real time.
The invention relates to a control device of an LED lamp tube, which comprises:
a memory for storing a program;
and the processor is used for executing the program, and the program enables the processor to execute the LED lamp tube control method.
From the above, the method, the system and the device for controlling the LED lamp tube provided by the invention can perform feedback control on the power supply of the LED lamp tube by monitoring the voltage value in real time, so that the LED lamp tube can not generate low-frequency flicker while having a high power factor, and can be realized without adopting an integrated IC, thereby effectively reducing the production cost.
While the preferred embodiments of the present invention have been illustrated and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.