A dimming method, a dimming control device, and a light source system

Abstract

The application provides a dimming method, a dimming control device and a light source system, comprising: when the light source system is enabled and the dimming control device is powered on for the first time, setting a conduction angle to a maximum value and gradually reducing the maximum value; detecting brightness information of the light source; obtaining a flicker frequency of the light source according to the brightness information of the light source and comparing the flicker frequency with a preset reference flicker frequency; when the flicker frequency is less than or equal to the reference flicker frequency for the first time, setting the conduction angle at this time to a lower limit of the conduction angle. The dimming method, the dimming control device and the light source system can adaptively set the lower limit of the conduction angle according to the reference flicker frequency, adaptively limit the lower limit of the dimming brightness, avoid low-frequency flicker of the light source at a low dimming brightness, evade flicker of the light source at a low brightness while ensuring the dimming range of the light source system, and improve the practicability of the light source system.

Description

Technical Field

[0001] This invention relates to the field of dimming technology for light source systems, and particularly to a dimming method, a dimming control device, and a light source system. Background Technology

[0002] In existing technologies, most light source systems use a thyristor (also known as a silicon controlled rectifier, or simply a silicon controlled rectifier) ​​connected in series with the light source, and a control circuit is set up to adjust the switching duty cycle of the thyristor, thereby adjusting the average value of the driving voltage of the light source to adjust the brightness of the light source.

[0003] In phase-cut dimming schemes, dimming is achieved by changing the conduction angle of the thyristor. Typically, this is achieved by varying the thyristor's conduction time within one switching cycle according to the selected dimming level (the ratio of target brightness to maximum brightness). For example... Figure 1 As shown, AC is the output current waveform of the AC power supply, Q is the waveform of the gate drive signal of the thyristor (high level for conduction, low level for turn-off), IL is the drive voltage waveform of the power supply, the switching period T1 of the thyristor matches the oscillation period T of the AC power supply (T1 = T / 2), and the phase angle φ is the 180-degree supplementary angle of the conduction angle.

[0004] Currently, the main light source on the market is LED (light emitting diode). Different brands and models of LED light sources have different driving circuits, and their compatibility with phase-cut dimming dimmers also varies. Especially at low power transmission levels (i.e., a phase angle greater than 135 degrees in each half-cycle (half a sine cycle) and greater than 315 degrees in each half-cycle), the mains sine wave will produce significant distortion after being phase-cut by the thyristor. This can lead to the LED light source driver being unable to provide a continuous and stable output to the LED chip, resulting in visible flickering or brightness fluctuations, reducing lighting effects, and even affecting the user's eye health.

[0005] For most people, flickering frequencies below 60 Hz are visible. The frequency of a flickering light source varies from person to person, and flickering occurring in the 60 Hz to 100 Hz range may also be visible to a minority of people.

[0006] Current technology typically allows users to set a lower dimming limit, such as 15%, on the dimmer via mechanical or software settings. Once the dimmer reaches this limit, it stops increasing the phase angle, thus avoiding the flickering or jittering issues at low brightness. However, this approach increases the complexity of product use. Users find it difficult to set the optimal dimming limit, making it hard for the system to balance optimizing the dimming range with resolving flickering. In practice, this can result in some loss of dimming range or flickering still occurring at low brightness, and poor compatibility between solutions to dimming range loss and flickering problems. Summary of the Invention

[0007] Based on this, the purpose of the present invention is to provide a dimming method, a dimming control device, and a light source system, so that the dimming control device can automatically match the actual light source and adaptively set the optimal dimming lower limit, thereby solving the problem of poor compatibility of solutions for dimming range loss and light source flicker.

[0008] This invention provides a dimming method for dimming control of a light source system, the light source system including a light source and a thyristor connected in series with an AC power supply, and a dimming control device for controlling the conduction time of the thyristor according to the adaptive dimming method, the dimming method comprising:

[0009] Obtain the lower limit of the conduction angle;

[0010] The target conduction angle is obtained based on the target brightness.

[0011] The driving voltage of the light source is detected to obtain the zero-crossing point of the driving voltage of the light source, so as to obtain the start time and cut-off time of the switching cycle of the thyristor based on the zero-crossing point;

[0012] The target conduction time of the thyristor in one switching cycle is obtained based on the target conduction angle and the lower limit of the conduction angle, and the conduction time of the thyristor is controlled to be consistent with the target conduction time based on the target conduction time;

[0013] The step of obtaining the lower limit of the conduction angle includes:

[0014] When the light source system is activated and the dimming control device is powered on for the first time, the conduction angle is set to the maximum value and then gradually decreased from the maximum value.

[0015] The brightness information of the light source is obtained through detection;

[0016] The flicker frequency of the light source is obtained based on the brightness information of the light source, and the flicker frequency is compared with a preset reference flicker frequency.

[0017] When the flashing frequency is first less than or equal to the reference flashing frequency, the conduction angle at this time is set as the lower limit of the conduction angle.

[0018] Optionally, the step of obtaining the lower limit of the conduction angle further includes:

[0019] If the flashing frequency is greater than the reference flashing frequency during the process of the conduction angle gradually decreasing from the maximum value to the minimum value, the minimum value of the conduction angle is set as the lower limit of the conduction angle.

[0020] Optionally, the on-state interval of the thyristor's switching cycle is after the off-state interval.

[0021] Optionally, it also includes:

[0022] The dimming control module is connected to at least one cloud server and mobile terminal for uploading data information and remote control of the light source system.

[0023] Optionally, the light source includes a light-emitting diode (LED).

[0024] Optionally, the reference flicker frequency can be set within a range of 60Hz to 100Hz.

[0025] According to another aspect of the present invention, a dimming control device is provided for dimming control of a light source system, the light source system including a light source and a thyristor connected in series with an AC power supply, the dimming control device comprising:

[0026] A light sensing module is used to detect and obtain the brightness information of the light source;

[0027] A zero-crossing detection module is used to detect the zero-crossing point of the driving voltage of the light source;

[0028] The control module is used to obtain the flicker frequency of the light source based on the brightness information, obtain the start time and end time of the switching cycle of the thyristor based on the zero crossing point, obtain the target conduction time based on the target brightness, and control the conduction time of the thyristor in one switching cycle to be consistent with the target conduction time based on the target conduction time.

[0029] The control module also controls the conduction time of the thyristor in one switching cycle according to the dimming method provided by the present invention.

[0030] Optionally, it also includes:

[0031] A wireless module is used to connect the control module to at least one of a cloud server and a mobile terminal for uploading data information and remote control of the dimming control device.

[0032] Optionally, the control module includes a microcontroller.

[0033] According to another aspect of the present invention, a light source system is provided, comprising:

[0034] A light source and a thyristor connected in series with an AC power supply;

[0035] The dimming control device provided according to the present invention.

[0036] The dimming method provided by this invention includes: when the light source system is activated and the dimming control device is powered on for the first time, setting the conduction angle to its maximum value and gradually decreasing it from the maximum value; detecting and obtaining the brightness information of the light source; obtaining the flicker frequency of the light source based on the brightness information and comparing the flicker frequency with a preset reference flicker frequency; when the flicker frequency is first less than or equal to the reference flicker frequency, setting the conduction angle at this time as the lower limit of the conduction angle. The dimming method of this invention can adaptively set the lower limit of the conduction angle according to the reference flicker frequency, adaptively limiting the lower limit of the dimming brightness, avoiding low-frequency flickering of the light source at low dimming brightness, and ensuring the dimming range of the light source system while avoiding flickering at low brightness, thus improving the practicality of the light source system.

[0037] The dimming control device provided by this invention performs dimming control according to the dimming method of this invention. It can adaptively set the lower limit of the conduction angle according to the reference flicker frequency, and adaptively limit the lower limit of the dimming brightness to avoid low-frequency flicker of the light source when the dimming brightness is low. While avoiding flicker of the light source at low brightness, it ensures the dimming range of the light source system and improves the practicality of dimming control.

[0038] The light source system provided by this invention includes a light source and a thyristor connected in series with an AC power supply, and a dimming control device provided by this invention connected to the drive circuit of the light source and the control terminal of the thyristor. The device can adaptively set the lower limit of the conduction angle according to the reference flicker frequency, adaptively limit the lower limit of the dimming brightness, avoid low-frequency flicker of the light source when the dimming brightness is low, and ensure the dimming range of the light source system while avoiding flicker of the light source at low brightness, thereby improving the practicality of the light source system. Attached Figure Description

[0039] Figure 1 The waveforms are shown for some signals in existing phase-cut dimming schemes.

[0040] Figure 2 This is a schematic diagram of the light source system in an embodiment of the present invention;

[0041] Figure 3 This is a schematic flowchart of the dimming method in an embodiment of the present invention;

[0042] Figure 4This is a partial flowchart of the dimming method in an embodiment of the present invention;

[0043] Explanation of key component symbols:

[0044] AC power AC light source 11 thyristor 12 dimming control device 20 Control module 21 Zero-crossing detection module 22 optical sensing module 23 wireless module 24

[0045] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0046] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Several embodiments of the invention are illustrated in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0047] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0049] Please refer to the figure. Figure 2 The figure shown is a schematic diagram of the light source system in an embodiment of the present invention.

[0050] In the light source system of this embodiment, there are a light source 11 and a thyristor 12 connected in series with an AC power supply, and a dimming control device 20 connected to the drive circuit of the light source 11 and the control terminal of the thyristor 12. The dimming control device 20 controls the average value of the drive current of the light source 11 by controlling the conduction time of the thyristor 12 in one switching cycle, so as to regulate the luminous brightness of the light source 11.

[0051] The dimming control device 20 performs dimming control according to the dimming method of the present invention embodiment. Figure 3 This is a schematic flowchart of the dimming method in an embodiment of the present invention. Figure 4 This is a partial flowchart illustrating the dimming method in an embodiment of the present invention. Please refer to the following for further details. Figure 3 and Figure 4 The dimming method of this invention includes:

[0052] Step S01: Obtain the lower limit of the conduction angle.

[0053] Step S02: Obtain the target conduction angle based on the target brightness.

[0054] Step S03: Detect the driving voltage of the light source to obtain the zero-crossing point of the driving voltage of the light source, so as to obtain the start time and cut-off time of the switching cycle of the thyristor based on the zero-crossing point.

[0055] Step S04: Obtain the target conduction time of the thyristor in one switching cycle based on the target conduction angle and the lower limit of the conduction angle, and control the conduction time of the thyristor to be consistent with the target conduction time based on the target conduction time.

[0056] The step of obtaining the lower limit of the conduction angle includes:

[0057] Step S11: When the light source system is enabled and the dimming control device is powered on for the first time, the conduction angle is set to the maximum value and then gradually decreased from the maximum value.

[0058] Step S12: Detect and obtain the brightness information of the light source.

[0059] Step S13: Obtain the flicker frequency of the light source based on the brightness information of the light source, and compare the flicker frequency with a preset reference flicker frequency.

[0060] Step S14: When the flashing frequency is first less than or equal to the reference flashing frequency, the conduction angle at this time is set as the lower limit of the conduction angle.

[0061] And, in step S15: during the process of the conduction angle gradually decreasing from the maximum value to the minimum value, when the flashing frequency is greater than the reference flashing frequency, the minimum value of the conduction angle is set as the lower limit of the conduction angle.

[0062] In step S11, the activation of the light source system mainly refers to connecting the series circuit of the light source 11 and the thyristor 12 to the AC power supply so that when the dimming control device 20 is powered on for the first time, the light source 11 can emit light in the step of obtaining the lower limit of the conduction angle, thus ensuring the effective execution of the setting of the lower limit of the conduction angle.

[0063] In step S11, the conduction angle is gradually reduced according to a preset pace (based on the size of the pace, it is actually a continuous linear reduction or a discrete reduction), and the comparison in step S13 is performed once each time the pace is reduced. Based on the result of each comparison, it is confirmed whether the setting of the lower limit of the conduction angle is completed, so as to confirm whether to continue to reduce the conduction angle.

[0064] In an optional embodiment, in step S15, the conduction angle when the flicker frequency is first less than or equal to the reference flicker frequency is added with a preset step and then set as the lower limit of the conduction angle. This ensures that the flicker frequency of the light source system with the lower limit of the conduction angle set is above the reference flicker frequency at the lower limit of brightness. This avoids the flicker frequency corresponding to the conduction angle when the flicker frequency is first less than the reference flicker frequency being significantly lower than the reference flicker frequency, thereby improving the solution to the light source flicker problem.

[0065] In the dimming control device 20 of this embodiment, there are light sensing modules 23 for detecting and obtaining the brightness information of the light source 11; zero-crossing detection modules 22 for detecting and obtaining the zero-crossing point of the driving voltage of the light source 11; and control modules 21 for obtaining the flicker frequency of the light source 11 according to the brightness information, obtaining the start time and end time of the switching cycle of the thyristor 12 according to the zero-crossing point, obtaining the target conduction time according to the target brightness, and controlling the conduction time of the thyristor 12 in one switching cycle to be consistent with the target conduction time according to the dimming method of this embodiment.

[0066] Among them, the zero-crossing detection module 22 and the control module 21 are basically the original modules of a general dimming control device. That is, the implementation of the main inventive point of this invention only requires the addition of the light sensing module 23 and the corresponding adjustment control module 21, resulting in low hardware and software costs.

[0067] In this embodiment, the dimming control device 20 further includes a wireless module 24, which is connected to the control module 21 and is used to connect the control module 21 to a mobile terminal (such as a mobile phone software application, wireless controller, etc.) or a cloud server for uploading data information and remote control of the dimming control device. The remote control includes the wireless transmission of relevant control signals such as the transmission of target brightness and the transmission of reference flicker frequency.

[0068] In this embodiment, the preset reference flicker frequency is 100Hz. In an optional embodiment, the reference flicker frequency is adjustable, and the adjustable range is 60Hz to 100Hz. The adjusted reference flicker frequency can be received by the wireless module 24. When the user knows his own visual light-sensing frequency, the reference flicker frequency other than 100Hz can be set to improve the dimming range of adaptive control and the adaptability to specific users.

[0069] The control module 21 is, for example, a single-chip microcomputer (or microcontroller unit).

[0070] In this embodiment, the on-state interval of the switching cycle of thyristor 12 is after the off-state interval. In an optional embodiment, the on-state interval of the switching cycle of thyristor 12 is before the off-state interval. The zero-crossing point detected by the zero-crossing detection module 22 corresponds to the cutoff time of the switching cycle of thyristor 12 and the start time of the subsequent switching cycle.

[0071] In this embodiment, the light source 11 includes a light-emitting diode.

[0072] In this embodiment, the thyristor 12 is used for switching control of the AC power supply. The light source 11 emits light under both forward and reverse driving voltages, corresponding to the thyristor 12 being a bidirectional thyristor that can conduct in both forward and reverse directions. In an optional embodiment, the driving circuit of the light source 11 further includes a rectifier circuit to convert the AC power into DC power. The corresponding thyristor 12 is a common unidirectional thyristor 12, with its unidirectional conduction direction consistent with the rectification direction of the rectified current.

[0073] In this embodiment, the target brightness refers to the brightness required by the user of the light source system. The user's actual needs are input into the light source system as the dimming target. The light source system converts the input target brightness (or other relevant control signals) to obtain the target conduction angle, and adjusts the conduction angle of the thyristor to the target conduction angle to achieve dimming. In an optional embodiment, the light source system automatically dims based on the ambient light brightness. The light source system converts the ambient light brightness or its own light source brightness according to a certain ratio, compares the two, and adjusts the conduction angle based on the comparison result. This automatically adjusts the output brightness as the ambient light brightness increases or decreases, achieving automatic dimming. In this embodiment, the target brightness refers to the output brightness obtained after automatic dimming, which is the same physical brightness as the target brightness in other control methods.

[0074] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0075] The above-described embodiments are merely illustrative of several specific implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A dimming method for dimming control of a light source system, the light source system comprising a light source and a thyristor connected in series with an AC power supply, and a dimming control device for controlling the conduction time of the thyristor according to the dimming method, characterized in that, The dimming method includes: Obtain the lower limit of the conduction angle; The target conduction angle is obtained based on the target brightness. The driving voltage of the light source is detected to obtain the zero-crossing point of the driving voltage of the light source, so as to obtain the start time and cut-off time of the switching cycle of the thyristor based on the zero-crossing point, wherein the zero-crossing point corresponds to the cut-off time of the switching cycle of the thyristor and the start time of the subsequent switching cycle. The target conduction time of the thyristor in one switching cycle is obtained based on the target conduction angle and the lower limit of the conduction angle, and the conduction time of the thyristor is controlled to be consistent with the target conduction time based on the target conduction time; The step of obtaining the lower limit of the conduction angle includes: When the light source system is activated and the dimming control device is powered on for the first time, the conduction angle is set to the maximum value and then gradually decreased from the maximum value. The brightness information of the light source is obtained through detection; The flicker frequency of the light source is obtained based on the brightness information of the light source, and the flicker frequency is compared with a preset reference flicker frequency. When the flashing frequency is first less than or equal to the reference flashing frequency, the conduction angle at this time is set as the lower limit of the conduction angle.

2. The dimming method according to claim 1, characterized in that, The step of obtaining the lower limit of the conduction angle further includes: If the flashing frequency is greater than the reference flashing frequency during the process of the conduction angle gradually decreasing from the maximum value to the minimum value, the minimum value of the conduction angle is set as the lower limit of the conduction angle.

3. The dimming method according to claim 1, characterized in that, The on-state interval of the thyristor's switching cycle is after the off-state interval.

4. The dimming method according to claim 1, characterized in that, Also includes: The dimming control device is connected to at least one cloud server and mobile terminal for uploading data information and remote control of the light source system.

5. The dimming method according to claim 1, characterized in that, The light source includes a light-emitting diode.

6. The dimming method according to claim 1, characterized in that, The reference flicker frequency is set within a range of 60Hz to 100Hz.

7. A dimming control device for dimming control of a light source system, the light source system comprising a light source and a thyristor connected in series with an AC power supply, characterized in that, The dimming control device includes: A light sensing module is used to detect and obtain the brightness information of the light source; A zero-crossing detection module is used to detect the zero-crossing point of the driving voltage of the light source; The control module is used to obtain the flicker frequency of the light source based on the brightness information, obtain the start time and end time of the switching cycle of the thyristor based on the zero crossing point, obtain the target conduction time based on the target brightness, and control the conduction time of the thyristor in one switching cycle to be consistent with the target conduction time based on the target conduction time. The control module further controls the conduction time of the thyristor in one switching cycle according to the dimming method according to any one of claims 1 to 6.

8. The dimming control device according to claim 7, characterized in that, Also includes: A wireless module is used to connect the control module to at least one of a cloud server and a mobile terminal for uploading data information and remote control of the dimming control device.

9. The dimming control device according to claim 7, characterized in that, The control module includes a microcontroller.

10. A light source system, characterized in that, include: A light source and a thyristor connected in series with an AC power supply; According to any one of claims 7 to 9, the dimming control device is connected to the drive circuit of the light source and the control terminal of the thyristor.

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