Silicon controlled rectifier dimming control method

Abstract

The invention relates to the field of LED dimming, in particular to a silicon controlled rectifier dimming control method, which ensures stable power supply of a power management chip through a small DC-DC converter, realizes accurate synchronization of a PWM signal and an alternating current by using a phase detection chip, dynamically adjusts the PWM duty ratio according to a dimming curve by a microcontroller, realizes smooth dimming, isolates the PWM signal by a high-speed photoelectric coupler, and improves the dimming efficiency. According to the technical scheme, the dimming control circuit is reasonable in design, interference is reduced, a driving circuit and a power MOS tube are matched, efficient dimming is ensured, in addition, the scheme supports user requirements or external signal dynamic adjustment, a dimming curve is optimized, flicker-free smooth brightness adjustment from 0% to 100% is achieved, and the dimming effect and user experience are remarkably improved.

Description

Technical Field

[0001] The present application relates to the field of LED dimming, and in particular to a thyristor dimming control method. Background Art

[0002] In current LED lighting technology, dimming function has become a key factor in improving user experience and energy saving. However, existing dimming technology has encountered some significant challenges in the implementation process, especially in terms of compatibility with different voltage inputs and ensuring dimming smoothness.

[0003] Current dimming technologies, especially those that rely on dedicated thyristor power ICs to detect input phase and change the PWM duty cycle to achieve dimming, are often not effectively compatible with the two common AC input voltages of 110VAC and 220VAC.

[0004] In addition to the voltage compatibility issue, the existing technology also has obvious deficiencies in dimming effects. During the dimming process, the LED lamp may experience brightness jitter or flicker, which not only affects the lighting quality and reduces the user experience, but may also have an adverse effect on the life of the LED lamp. Summary of the invention

[0005] In order to improve the voltage compatibility and dimming effect of an LED dimming system, the present application provides a thyristor dimming control method.

[0006] In a first aspect, the present application provides a thyristor dimming control method, comprising the following steps: S1: Uses a small DC-DC converter circuit to provide a stable 5V auxiliary power supply for the power management chip; S2: Use the phase detection chip to detect the zero-crossing point of the AC input voltage to determine the phase. Based on the detected phase information, the power management chip adjusts the trigger point of the PWM signal accordingly. S3: Based on the phase detection result, a PWM signal synchronized with the input voltage phase is generated through the timer module of the microcontroller. The microcontroller adjusts the duty cycle of the PWM signal according to the preset dimming curve to achieve smooth dimming. S4: Use a high-speed optocoupler to isolate the PWM signal generated by the microcontroller from the subsequent circuit, reducing signal interference during transmission; S5: Use the PWM signal output by the photocoupler to drive the power MOS tube of the subsequent stage through the driving circuit to provide sufficient driving current to ensure that the MOS tube switches quickly and accurately to achieve efficient dimming; S6: Dynamically adjust the duty cycle of the PWM signal according to user needs or external dimming signals, and optimize the dimming curve to ensure that the PWM signal frequency is high enough at low brightness, reduce flickering, and achieve smooth brightness adjustment from 0% to 100%.

[0007] Optionally, the method of using a small linear regulator to provide a stable 5V auxiliary power supply for the power management chip includes the following steps: S11: Detect the power input range to determine whether a low voltage or high voltage power supply mode is required; S12: A small DC-DC converter circuit is used to convert the input voltage into a stable 5V output to power the power management chip; S13: Test the output stability of the auxiliary power supply under different input voltage and load conditions to ensure stable power supply in all phases; S14: Add an overvoltage and undervoltage protection circuit to the auxiliary power supply circuit, which is directly connected to the power input terminal. When it is detected that the input voltage exceeds a preset safety range, the connection between the power supply and the subsequent circuit is cut off.

[0008] Optionally, the phase detection chip is used to detect the zero-crossing point of the AC input voltage to determine the phase. The power management chip adjusts the trigger point of the PWM signal accordingly based on the detected phase information, including the following steps: S21: A phase detection circuit based on zero-crossing detection is used to detect the zero-crossing point of the AC input voltage; S22: Amplify the detected weak signal through an operational amplifier and shape it through a Schmitt trigger to ensure the clarity and stability of the signal; S23: Capture the shaped signal through the external interrupt pin of the microcontroller and extract the phase information for subsequent PWM signal generation; S24: Under different input voltage conditions, the phase information is calibrated to ensure the accuracy of phase detection to adapt to different power grid environments.

[0009] Optionally, based on the phase detection result, a PWM signal synchronized with the input voltage phase is generated through a timer module of a microcontroller, and the microcontroller adjusts the duty cycle of the PWM signal according to a preset dimming curve to achieve smooth dimming, including the following steps: S31: configuring the timer module of the microcontroller, setting the prescaler and the counter to generate a PWM signal synchronized with the input voltage phase; S32: according to dimming requirements, setting the frequency, duty cycle and dead time of the PWM signal to achieve smooth dimming; S33: sending the generated PWM signal to the optocoupler via the PWM output pin of the microcontroller; S34: During the dimming process, the output state of the PWM signal is monitored and fine-tuned according to the actual dimming effect to ensure the smoothness and stability of the dimming.

[0010] Optionally, the high-speed photocoupler is used to isolate the PWM signal generated by the microcontroller from the subsequent circuit, thereby reducing interference of the signal during transmission, and the steps include: S41: confirming the PWM signal level output by the microcontroller, and confirming the design parameters of the photocoupler drive circuit based on the obtained PWM signal level; S42: Connect a photocoupler to the driving circuit and use an oscilloscope to monitor the signal at the output end of the photocoupler; S43: Transmitting the PWM signal from the microcontroller side to the subsequent circuit side through a photocoupler to achieve electrical isolation; S44: On the back-end circuit side, a Schmitt trigger is used to shape the signal output by the optocoupler to ensure that the signal is clear and stable.

[0011] Optionally, the PWM signal output by the photocoupler is used to drive the power MOS tube of the subsequent stage through the driving circuit to provide sufficient driving current to ensure that the MOS tube switches quickly and accurately to achieve efficient dimming, including the following steps: S51: Select the MOS tube according to the output power requirement, combined with the rated current, voltage, on-resistance and thermal performance of the MOS tube; S52: Under no-load and full-load conditions, use an oscilloscope to monitor the gate voltage and drain current of the MOS tube to obtain the test results; S53: According to the test results, optimize the drive circuit parameters, including the drive current and the gate resistance.

[0012] Optionally, dynamically adjusting the duty cycle of the PWM signal according to user demand or an external dimming signal, while optimizing the dimming curve, ensuring that the PWM signal frequency is high enough at low brightness, reducing flickering, and achieving smooth brightness adjustment from 0% to 100%, includes the following steps: S61: according to dimming requirements, setting a dimming curve, such as a linear, exponential or logarithmic curve, to achieve different dimming effects; S62: Test the dimming effect at different brightness settings; S63: Monitor the stability of the dimming system under long-term operation conditions and record brightness changes and abnormal phenomena; S64: According to the test and evaluation results, adjust the PWM signal parameters, including the frequency and duty cycle, and adjust the drive current parameters.

[0013] In a second aspect, the present application provides a thyristor dimming control system, which is applied to the above-mentioned thyristor dimming control method, including: The power management module provides a stable power supply for the entire dimming system, including a small DC-DC converter circuit to convert the input power into the stable 5V voltage required by the system; The phase detection and control module uses a phase detection chip to monitor the zero-crossing point of the AC input voltage to determine the phase, and adjusts the trigger point of the PWM signal based on the detected phase information to ensure that the PWM signal is synchronized with the phase of the AC power supply; The PWM signal generation and dimming control module generates a PWM signal that is phase-synchronized with the input voltage based on the phase detection result, and adjusts the duty cycle of the PWM signal according to a preset dimming curve to achieve smooth dimming; The signal isolation and driving module isolates the PWM signal generated by the microcontroller from the subsequent circuit.

[0014] In a third aspect, the present application provides an electronic device, which adopts the following technical solution: An electronic device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of a thyristor dimming control method as described in any one of the above when executing the computer program.

[0015] In a fourth aspect, the present application provides a computer-readable storage medium, which adopts the following technical solution: A computer-readable storage medium comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of a thyristor dimming control method as described in any one of the above when executing the computer program.

[0016] In summary, this application includes the following beneficial technical effects: 1. The DC-DC converter circuit provides a stable 5V auxiliary power supply for the power management chip, ensuring that the chip can work stably under different input voltages (such as 110VAC and 220VAC), enhancing the voltage compatibility of the dimming system, and enabling the dimming technology to adapt to the power grid standards in different regions of the world; 2. Through the collaborative work of the phase detection chip and the microcontroller, the PWM signal is accurately synchronized with the AC power phase. The microcontroller dynamically adjusts the duty cycle of the PWM signal according to the preset dimming curve, ensuring smooth brightness adjustment from 0% to 100%. Especially at low brightness, the PWM signal frequency is high enough to effectively reduce brightness jitter and flicker, significantly improving the dimming effect and user experience; 3. The use of high-speed photocouplers to isolate PWM signals reduces interference during signal transmission and ensures the purity and stability of the PWM signal. At the same time, the driving circuit drives the power MOS tube, providing sufficient driving current to ensure the fast and accurate switching of the MOS tube, thereby improving the dimming efficiency and the overall stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a flow chart of a thyristor dimming control method in an embodiment of the present application.

[0018] Figure 2 It is a sub-step flow chart of S1 in the embodiment of the present application.

[0019] Figure 3 It is a sub-step flow chart of S2 in the embodiment of the present application.

[0020] Figure 4 It is a sub-step flow chart of S3 in the embodiment of the present application.

[0021] Figure 5 It is a sub-step flow chart of S4 in the embodiment of the present application.

[0022] Figure 6 It is a sub-step flow chart of S5 in the embodiment of the present application.

[0023] Figure 7 It is a sub-step flow chart of S6 in the embodiment of the present application. DETAILED DESCRIPTION

[0024] The following is combined with Figure 1-Figure 7 This application is described in further detail.

[0025] Reference Figure 1 The present application discloses a thyristor dimming control method, comprising the following steps: S1: A small DC-DC converter circuit is used to provide a stable 5V auxiliary power supply for the power management chip.

[0026] Reference Figure 1 , step S1 correspondingly includes the following sub-steps: S11: Detect the power input range to determine whether a low voltage or high voltage power supply mode is required; S12: A small DC-DC converter circuit is used to convert the input voltage into a stable 5V output to power the power management chip; S13: Test the output stability of the auxiliary power supply under different input voltage and load conditions to ensure stable power supply in all phases; S14: Add an overvoltage and undervoltage protection circuit to the auxiliary power supply circuit, which is directly connected to the power input terminal. When it is detected that the input voltage exceeds a preset safety range, the connection between the power supply and the subsequent circuit is cut off.

[0027] The following examples are given for steps S11 to S14.

[0028] First, the LM339 voltage comparator chip is used to detect the power input range and determine whether a low-voltage or high-voltage power supply mode is required. The LM339 has two independent voltage comparators that can set two different threshold voltages to detect overvoltage and undervoltage conditions.

[0029] Assume that the low voltage threshold is set to 100VAC and the high voltage threshold is set to 250VAC. When the input voltage is lower than 100VAC, the output of LM339 will trigger the low voltage power supply mode; when the input voltage is higher than 250VAC, the high voltage power supply mode will be triggered.

[0030] Furthermore, LM2576-5.0 is selected, which is a fixed output voltage DC-DC converter that can convert the input voltage into a stable 5V output. LM2576-5.0 has high efficiency and stability and is suitable for a wide range of input voltages.

[0031] Connect the LM2576-5.0 with appropriate inductors, capacitors, and diodes to form a step-down DC-DC converter circuit. The inductor is selected as 10μH and the output capacitor is selected as 1000μF to ensure the stability of the output voltage.

[0032] In addition, the output stability of the auxiliary power supply was tested using an oscilloscope and an ammeter under different input voltages (100VAC to 250VAC) and load conditions (from no load to full load). This ensured that a stable 5V supply could be provided in all phases, with an output voltage fluctuation of no more than ±1%. The above tests were repeated at different ambient temperatures (0°C to 50°C) to ensure that the power supply could maintain stable output over a wide temperature range.

[0033] Furthermore, an overvoltage protection diode (such as a TVS diode) and an undervoltage lockout circuit (such as the LM3914) are used to cut off the connection between the power supply and the subsequent circuit when it is detected that the input voltage exceeds a preset safety range, thereby protecting the entire system from damage.

[0034] A relay or MOSFET switch is added between the power input and the DC-DC converter. When the overvoltage or undervoltage protection circuit detects an abnormality, the control signal will disconnect the relay or cut off the MOSFET, cutting off the connection between the power supply and the subsequent circuit.

[0035] Replay Figure 1, after step S1, the following steps are also included: S2: Use the phase detection chip to detect the zero-crossing point of the AC input voltage to determine the phase. Based on the detected phase information, the power management chip adjusts the trigger point of the PWM signal accordingly.

[0036] Reference Figure 3 , step S2 correspondingly includes the following sub-steps.

[0037] S21: A phase detection circuit based on zero-crossing detection is used to detect the zero-crossing point of the AC input voltage; S22: Amplify the detected weak signal through an operational amplifier and shape it through a Schmitt trigger to ensure the clarity and stability of the signal; S23: Capture the shaped signal through the external interrupt pin of the microcontroller and extract the phase information for subsequent PWM signal generation; S24: Under different input voltage conditions, the phase information is calibrated to ensure the accuracy of phase detection to adapt to different power grid environments.

[0038] The following examples are given for steps S21 to S24.

[0039] First, the LM339 voltage comparator is used as a zero-crossing detector to detect the zero-crossing point of the AC input voltage. The LM339 has two independent voltage comparators, one for detecting the positive zero-crossing point and the other for detecting the negative zero-crossing point. The reference voltage is set by the voltage-dividing resistor network so that it is near the zero point of the AC input voltage, ensuring that the LM339 can accurately detect the zero-crossing point.

[0040] Furthermore, an operational amplifier (such as LM358) is used to amplify the detected weak signal. LM358 has high gain and bandwidth, which is suitable for signal amplification. Then, the amplified signal is shaped by a Schmitt trigger (such as CD40106) to ensure the clarity and stability of the signal. The Schmitt trigger has a hysteresis voltage, which can effectively eliminate the noise in the signal.

[0041] At the same time, the STM32F103C8T6 microcontroller has multiple external interrupt pins to capture the shaped signal. The external interrupt pins of the microcontroller are configured to trigger an interrupt when the rising or falling edge of the signal is detected. In the interrupt service program, the trigger time of the signal is recorded to calculate the phase information.

[0042] Under different input voltage conditions, the phase calibration parameters in the microcontroller are adjusted by comparing the actual phase information with the theoretical phase information. For example, if the detected phase information deviates from the theoretical value, the phase information can be calibrated by adjusting the threshold voltage of the interrupt trigger.

[0043] In addition, phase information detection is performed under different power grid environments (such as different frequencies and voltage fluctuations) to ensure that the phase detection circuit can accurately adapt to various power grid environments.

[0044] Replay Figure 1 , the following steps are also included after step S2.

[0045] S3: Based on the phase detection result, a PWM signal synchronized with the input voltage phase is generated through the timer module of the microcontroller. The microcontroller adjusts the duty cycle of the PWM signal according to the preset dimming curve to achieve smooth dimming.

[0046] Reference Figure 4 , step S3 correspondingly includes the following sub-steps.

[0047] S31: configuring the timer module of the microcontroller, setting the prescaler and the counter to generate a PWM signal synchronized with the input voltage phase; S32: according to dimming requirements, setting the frequency, duty cycle and dead time of the PWM signal to achieve smooth dimming; S33: sending the generated PWM signal to the optocoupler via the PWM output pin of the microcontroller; S34: During the dimming process, the output state of the PWM signal is monitored and fine-tuned according to the actual dimming effect to ensure the smoothness and stability of the dimming.

[0048] The following examples are given for steps S31 to S34.

[0049] First, in the STM32F103C8T6 microcontroller, select TIM2 as the timer for PWM signal generation. TIM2 is a 16-bit timer with 4 channels that can generate 4 PWM signals.

[0050] Assuming the input clock frequency is 72MHz, in order to generate a PWM signal that is synchronized with the input voltage phase, set the prescaler to 3600 (i.e. 72MHz / 3600 = 20kHz) and the counter period to 10000, so that a PWM signal with a frequency of 20kHz can be generated, which is synchronized with the 50Hz AC input voltage phase. And keep the settings of the prescaler and counter to ensure that the PWM signal frequency is 20kHz.

[0051] Furthermore, the duty cycle of the PWM signal is set according to the dimming requirements. For example, in order to achieve smooth dimming from 0% to 100%, the duty cycle can be gradually increased from 0% to 100%. In order to prevent the upper and lower bridge arms from being turned on at the same time, an appropriate dead time is set, such as 5 μs.

[0052] Then configure channel 1 of TIM2 as PWM output mode and connect it to the PB1 pin of the microcontroller, which is connected to the driver circuit of the optocoupler. In the timer interrupt service routine, the compare register value of the PWM signal is updated according to the current duty cycle setting to generate a PWM signal.

[0053] In addition, use an oscilloscope to monitor the PWM signal of the PB1 pin to ensure that the signal frequency, duty cycle and dead time meet expectations. During the dimming process, observe the dimming effect, such as whether the brightness changes smoothly and whether there is flickering or instability. Then, according to the actual dimming effect, fine-tune the frequency, duty cycle and dead time of the PWM signal to ensure the smoothness and stability of the dimming.

[0054] Replay Figure 1 , step S3 and the corresponding steps include the following steps.

[0055] S4: A high-speed optocoupler is used to isolate the PWM signal generated by the microcontroller from the subsequent circuit, reducing interference in the signal during transmission.

[0056] Reference Figure 5 , step S4 includes the following sub-steps.

[0057] S41: confirming the PWM signal level output by the microcontroller, and confirming the design parameters of the photocoupler drive circuit based on the obtained PWM signal level; S42: Connect a photocoupler to the driving circuit and use an oscilloscope to monitor the signal at the output end of the photocoupler; S43: Transmitting the PWM signal from the microcontroller side to the subsequent circuit side through a photocoupler to achieve electrical isolation; S44: On the back-end circuit side, a Schmitt trigger is used to shape the signal output by the optocoupler to ensure that the signal is clear and stable.

[0058] The following examples are given for steps S41-S44.

[0059] First, use an oscilloscope to measure the PWM signal level output by the microcontroller to ensure that the high and low levels of the signal meet expectations. For example, for a 3.3V microcontroller, the high level should be 3.3V and the low level should be 0V. Based on the obtained PWM signal level, confirm the design parameters of the optocoupler drive circuit. For example, when selecting an optocoupler, ensure that the current drive capability of its input side matches the current drive capability of the microcontroller's PWM output pin.

[0060] At the same time, the HCPL-J600 photocoupler is selected, which has a high isolation voltage and good signal transmission characteristics, and is suitable for the transmission of PWM signals. The input side of the photocoupler is connected to the PWM output pin of the microcontroller, and the output side is connected to the subsequent circuit. Use an oscilloscope to monitor the signal at the output end of the photocoupler to ensure that the signal is clear and stable.

[0061] Furthermore, the PWM signal is transmitted from the microcontroller side to the subsequent circuit side through a photocoupler to achieve electrical isolation. There is no direct electrical connection between the input side and the output side of the photocoupler. Signal transmission is performed through optical signals, which effectively isolates the microcontroller and the subsequent circuit, improving the safety of the system.

[0062] Then use the 74HC14 Schmitt trigger, which has a hysteresis voltage, to effectively eliminate the noise in the signal and ensure the clarity and stability of the signal. On the back-end circuit side, the signal output by the photocoupler is connected to the input end of the Schmitt trigger, and the signal is shaped by the Schmitt trigger. The output signal of the Schmitt trigger will be used as the control signal of the back-end circuit to control the conduction and shutdown of the thyristor.

[0063] The design of the optocoupler drive circuit is described below with examples.

[0064] Select the photocoupler model: First, select a high-speed photocoupler, such as HCPL-J600, which has a high data transmission rate and is suitable for fast transmission of PWM signals.

[0065] Determine the PWM signal level: Confirm the PWM signal level output by the microcontroller, assuming it is 3.3V or 5V. This will determine the design parameters of the optocoupler driver circuit.

[0066] Design a drive circuit: Design a simple drive circuit, including a current limiting resistor and a pull-up resistor. The current limiting resistor is used to limit the current flowing through the photocoupler light-emitting diode to prevent overcurrent damage; the pull-up resistor is used to ensure that the light-emitting diode of the photocoupler can be completely turned off when the PWM signal is at a low level.

[0067] Calculation of current limiting resistor: Assume that the forward voltage of the light-emitting diode of the optocoupler is 1.2V and the maximum allowable current is 20mA. According to Ohm's law, the calculation formula of the current limiting resistor R1 is: [R1 = \frac{V_{CC} - V_{LED}}{I_{LED}}]. If the PWM signal level is 5V, then [R1 = \frac{5V - 1.2V}{20mA} = 190\Omega]. In practical applications, the closest nominal value can be selected, such as 200Ω.

[0068] Pull-up resistor selection: The selection of pull-up resistor R2 depends on the output capability of the microcontroller. Assuming that the maximum pull current that the microcontroller can withstand is 20mA, the calculation formula of pull-up resistor R2 is: [R2 = \frac{V_{CC}}{I_{max}}]. If the PWM signal level is 5V, then [R2 = \frac{5V}{20mA} = 250\Omega]. In practical applications, a larger value, such as 1kΩ, can be selected to reduce power consumption.

[0069] Circuit layout and testing: After completing the circuit design, perform circuit layout to ensure that the signal line layout is reasonable and reduce signal interference. Then, use an oscilloscope to test the waveform of the PWM signal to ensure the integrity and stability of the signal.

[0070] Photocoupler response test: Connect a photocoupler to the circuit and use an oscilloscope to monitor the signal at the output of the photocoupler to ensure that the PWM signal can effectively drive the light-emitting diode of the photocoupler to achieve fast signal transmission.

[0071] Replay Figure 1 , after step S4, the following steps are also included: S5: Use the PWM signal output by the photocoupler to drive the power MOS tube of the subsequent stage through the driving circuit to provide sufficient driving current to ensure that the MOS tube switches quickly and accurately to achieve efficient dimming; Reference Figure 6 , step S5 correspondingly includes the following sub-steps: S51: Select the MOS tube according to the output power requirement, combined with the rated current, voltage, on-resistance and thermal performance of the MOS tube; S52: Under no-load and full-load conditions, use an oscilloscope to monitor the gate voltage and drain current of the MOS tube to obtain the test results; S53: According to the test results, optimize the drive circuit parameters, including the drive current and the gate resistance.

[0072] The following examples are given for steps S51-S53.

[0073] First, calculate the maximum current and voltage that the MOS tube needs to withstand based on the output power requirements of the dimming system. For example, if the maximum output power of the system is 100W and the operating voltage is 24V, then the maximum current is I = P / V = ​​100W / 24V = 4.17A.

[0074] It should be noted that when selecting a MOS tube, you should ensure that its rated current is greater than the maximum current and its rated voltage is greater than the operating voltage. At the same time, consider the on-resistance RDS(ON) of the MOS tube and select a lower RDS(ON) to reduce power loss. In addition, based on the thermal performance mentioned in the reference material, calculate the maximum power dissipation of the MOS tube to ensure that the MOS tube will not overheat during operation.

[0075] Furthermore, an oscilloscope is used to monitor the gate voltage and drain current of the MOS tube under no-load and full-load conditions. Under no-load conditions, the load current of the MOS tube is 0; under full-load conditions, the load current of the MOS tube is the maximum current. The gate voltage and drain current of the MOS tube under no-load and full-load conditions, as well as the temperature change of the MOS tube, are recorded. These data will be used to evaluate the performance and stability of the MOS tube.

[0076] In addition, according to the test results, analyze the performance of the MOS tube under different conditions, such as the stability of the gate voltage, the fluctuation of the drain current, the temperature change of the MOS tube, etc. According to the test results, optimize the drive circuit parameters, including the drive current and the gate resistance. For example, if the test results show that the gate voltage is unstable, the gate resistance can be increased to reduce the fluctuation of the gate voltage; if the temperature of the MOS tube is too high, a heat sink can be added or the heat dissipation design can be optimized.

[0077] Replay Figure 1 , after step S5, the following steps are also included.

[0078] S6: Dynamically adjust the duty cycle of the PWM signal according to user needs or external dimming signals, and optimize the dimming curve to ensure that the PWM signal frequency is high enough at low brightness, reduce flickering, and achieve smooth brightness adjustment from 0% to 100% Reference Figure 7 , step S6 correspondingly includes the following sub-steps.

[0079] S61: according to dimming requirements, setting a dimming curve, such as a linear, exponential or logarithmic curve, to achieve different dimming effects; S62: Test the dimming effect at different brightness settings; S63: Monitor the stability of the dimming system under long-term operation conditions and record brightness changes and abnormal phenomena; S64: According to the test and evaluation results, adjust the PWM signal parameters, including the frequency and duty cycle, and adjust the drive current parameters.

[0080] The following examples are given for steps S61 to S64.

[0081] First, select a dimming curve based on dimming requirements. For example, a linear curve is suitable for applications that require linear dimming, an exponential curve is suitable for applications that require nonlinear dimming, and a logarithmic curve is suitable for applications that require slow brightness changes. In the microcontroller, set the parameters of the dimming curve, such as the slope of the linear curve, the exponent of the exponential curve, the logarithmic base of the logarithmic curve, etc. These parameters will be used to calculate the duty cycle of the PWM signal to achieve different dimming effects.

[0082] Furthermore, different brightness values ​​are set in the microcontroller, such as 0%, 25%, 50%, 75%, 100%, etc. Under different brightness settings, a photometer is used to monitor the dimming effect and record the brightness value and brightness change curve. At the same time, an oscilloscope is used to monitor the frequency and duty cycle of the PWM signal to ensure that the signal parameters meet expectations.

[0083] At the same time, monitor the stability of the dimming system under long-term operation conditions, and record brightness changes and abnormal phenomena. For example, you can set the dimming system to run for 24 hours at different brightness settings, record the brightness change curve and abnormal phenomena, such as brightness fluctuations, flickering, overheating, etc., and use a data recorder to record the operating data of the dimming system, such as brightness value, PWM signal parameters, MOS tube temperature, etc., for subsequent analysis and evaluation.

[0084] In addition, according to the test results, adjust the PWM signal parameters, including frequency and duty cycle, and adjust the drive current parameters to optimize the dimming effect and system stability. For example, if the test results show that the brightness change curve is not smooth, you can adjust the frequency and duty cycle of the PWM signal to improve the smoothness of the curve; if the temperature of the MOS tube is too high, you can adjust the drive current parameters to reduce the power dissipation of the MOS tube.

[0085] The present application provides a thyristor dimming control system, which is applied to the above-mentioned thyristor dimming control method, including: The power management module provides a stable power supply for the entire dimming system, including a small DC-DC converter circuit to convert the input power into the stable 5V voltage required by the system; The phase detection and control module uses a phase detection chip to monitor the zero-crossing point of the AC input voltage to determine the phase, and adjusts the trigger point of the PWM signal based on the detected phase information to ensure that the PWM signal is synchronized with the phase of the AC power supply; The PWM signal generation and dimming control module generates a PWM signal that is phase-synchronized with the input voltage based on the phase detection result, and adjusts the duty cycle of the PWM signal according to a preset dimming curve to achieve smooth dimming; The signal isolation and driving module isolates the PWM signal generated by the microcontroller from the subsequent circuit.

[0086] Correspondingly, the power management module is used to ensure that the entire dimming system obtains a stable and accurate 5V power supply. This is achieved through the built-in DC-DC converter circuit, which can convert the input power into the stable voltage required by the system. The phase detection and control module uses an advanced phase detection chip to monitor the zero-crossing point of the AC input voltage in real time, accurately determine the phase, and then adjust the trigger point of the PWM signal to ensure that the PWM signal is synchronized with the phase of the AC power supply, which is the key to achieving precise dimming. Based on the phase detection result, the PWM signal generation and dimming control module generates a PWM signal that is synchronized with the input voltage phase. By adjusting the duty cycle of the PWM signal, a smooth and flicker-free dimming effect is achieved according to the preset dimming curve. Finally, the signal isolation and drive module isolates the PWM signal generated by the microcontroller from the subsequent circuit, and achieves electrical isolation through components such as optocouplers to protect the system from voltage fluctuations while ensuring clear transmission of the PWM signal. Through the collaborative work of these modules, the entire system not only improves the accuracy and stability of dimming, but also enhances the safety and reliability of the system, providing users with a high-quality dimming experience.

[0087] This embodiment also provides an electronic device. The electronic device includes a processor, a memory, a network interface and a database connected through a system bus. Among them, the processor of the electronic device is used to provide computing and control capabilities. The memory of the electronic device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The network interface of the electronic device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a thyristor dimming control method is implemented: S1: Uses a small DC-DC converter circuit to provide a stable 5V auxiliary power supply for the power management chip; S2: Use the phase detection chip to detect the zero-crossing point of the AC input voltage to determine the phase. Based on the detected phase information, the power management chip adjusts the trigger point of the PWM signal accordingly. S3: Based on the phase detection result, a PWM signal synchronized with the input voltage phase is generated through the timer module of the microcontroller. The microcontroller adjusts the duty cycle of the PWM signal according to the preset dimming curve to achieve smooth dimming. S4: Use a high-speed optocoupler to isolate the PWM signal generated by the microcontroller from the subsequent circuit, reducing signal interference during transmission; S5: Use the PWM signal output by the photocoupler to drive the power MOS tube of the subsequent stage through the driving circuit to provide sufficient driving current to ensure that the MOS tube switches quickly and accurately to achieve efficient dimming; S6: Dynamically adjust the duty cycle of the PWM signal according to user needs or external dimming signals, and optimize the dimming curve to ensure that the PWM signal frequency is high enough at low brightness, reduce flickering, and achieve smooth brightness adjustment from 0% to 100%.

[0088] When the computer program is executed by a processor, any one of the thyristor dimming control methods in the above method embodiments can be implemented.

[0089] This embodiment further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the following steps are implemented: S1: Uses a small DC-DC converter circuit to provide a stable 5V auxiliary power supply for the power management chip; S2: Use the phase detection chip to detect the zero-crossing point of the AC input voltage to determine the phase. Based on the detected phase information, the power management chip adjusts the trigger point of the PWM signal accordingly. S3: Based on the phase detection result, a PWM signal synchronized with the input voltage phase is generated through the timer module of the microcontroller. The microcontroller adjusts the duty cycle of the PWM signal according to the preset dimming curve to achieve smooth dimming. S4: Use a high-speed optocoupler to isolate the PWM signal generated by the microcontroller from the subsequent circuit, reducing signal interference during transmission; S5: Use the PWM signal output by the photocoupler to drive the power MOS tube of the subsequent stage through the driving circuit to provide sufficient driving current to ensure that the MOS tube switches quickly and accurately to achieve efficient dimming; S6: Dynamically adjust the duty cycle of the PWM signal according to user needs or external dimming signals, and optimize the dimming curve to ensure that the PWM signal frequency is high enough at low brightness, reduce flickering, and achieve smooth brightness adjustment from 0% to 100%.

[0090] When the computer program is executed by a processor, any one of the thyristor dimming control methods in the above method embodiments can be implemented.

[0091] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0092] Those skilled in the art will clearly understand that for the sake of convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the system can be divided into different functional units or modules to complete all or part of the functions described above.

[0093] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application is described in detail in the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some of the technical features therein by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A thyristor dimming control method, characterized in that: The following steps are involved: S1: Uses a small DC-DC converter circuit to provide a stable 5V auxiliary power supply for the power management chip; S2: Use the phase detection chip to detect the zero-crossing point of the AC input voltage to determine the phase. Based on the detected phase information, the power management chip adjusts the trigger point of the PWM signal accordingly. S3: Based on the phase detection result, a PWM signal synchronized with the input voltage phase is generated through the timer module of the microcontroller. The microcontroller adjusts the duty cycle of the PWM signal according to the preset dimming curve to achieve smooth dimming. S4: Use a high-speed optocoupler to isolate the PWM signal generated by the microcontroller from the subsequent circuit, reducing signal interference during transmission; S5: Use the PWM signal output by the photocoupler to drive the power MOS tube of the subsequent stage through the driving circuit to provide sufficient driving current to ensure that the MOS tube switches quickly and accurately to achieve efficient dimming; S6: Dynamically adjust the duty cycle of the PWM signal according to user needs or external dimming signals, and optimize the dimming curve to ensure that the PWM signal frequency is high enough at low brightness, reduce flickering, and achieve smooth brightness adjustment from 0% to 100%.

2. A thyristor dimming control method according to claim 1, characterized in that: The method of using a small linear regulator to provide a stable 5V auxiliary power supply for the power management chip includes the following steps: S11: Detect the power input range to determine whether a low voltage or high voltage power supply mode is required; S12: A small DC-DC converter circuit is used to convert the input voltage into a stable 5V output to power the power management chip; S13: Test the output stability of the auxiliary power supply under different input voltage and load conditions to ensure stable power supply in all phases; S14: Add an overvoltage and undervoltage protection circuit to the auxiliary power supply circuit, which is directly connected to the power input terminal. When it is detected that the input voltage exceeds a preset safety range, the connection between the power supply and the subsequent circuit is cut off.

3. The thyristor dimming control method according to claim 1, characterized in that: The phase detection chip is used to detect the zero-crossing point of the AC input voltage, thereby determining the phase. The power management chip adjusts the trigger point of the PWM signal accordingly based on the detected phase information, including the following steps: S21: A phase detection circuit based on zero-crossing detection is used to detect the zero-crossing point of the AC input voltage; S22: Amplify the detected weak signal through an operational amplifier and shape it through a Schmitt trigger to ensure the clarity and stability of the signal; S23: Capture the shaped signal through the external interrupt pin of the microcontroller and extract the phase information for subsequent PWM signal generation; S24: Under different input voltage conditions, the phase information is calibrated to ensure the accuracy of phase detection to adapt to different power grid environments.

4. The thyristor dimming control method according to claim 1, characterized in that: Based on the phase detection result, a PWM signal synchronized with the input voltage phase is generated through a timer module of the microcontroller, and the microcontroller adjusts the duty cycle of the PWM signal according to a preset dimming curve to achieve smooth dimming, including the following steps: S31: configuring the timer module of the microcontroller, setting the prescaler and the counter to generate a PWM signal synchronized with the input voltage phase; S32: according to dimming requirements, setting the frequency, duty cycle and dead time of the PWM signal to achieve smooth dimming; S33: sending the generated PWM signal to the optocoupler via the PWM output pin of the microcontroller; S34: During the dimming process, the output state of the PWM signal is monitored and fine-tuned according to the actual dimming effect to ensure the smoothness and stability of the dimming.

5. The thyristor dimming control method according to claim 1, characterized in that: The method uses a high-speed photocoupler to isolate the PWM signal generated by the microcontroller from the subsequent circuit, thereby reducing interference of the signal during transmission, and includes the following steps: S41: confirming the PWM signal level output by the microcontroller, and confirming the design parameters of the photocoupler drive circuit based on the obtained PWM signal level; S42: Connect a photocoupler to the driving circuit and use an oscilloscope to monitor the signal at the output end of the photocoupler; S43: Transmitting the PWM signal from the microcontroller side to the subsequent circuit side through a photocoupler to achieve electrical isolation; S44: On the back-end circuit side, a Schmitt trigger is used to shape the signal output by the optocoupler to ensure that the signal is clear and stable.

6. The thyristor dimming control method according to claim 1, characterized in that: The PWM signal output by the photocoupler is used to drive the power MOS tube of the subsequent stage through the driving circuit to provide sufficient driving current, ensure that the MOS tube is switched quickly and accurately, and realize efficient dimming, including the following steps: S51: Select the MOS tube according to the output power requirement, combined with the rated current, voltage, on-resistance and thermal performance of the MOS tube; S52: Under no-load and full-load conditions, use an oscilloscope to monitor the gate voltage and drain current of the MOS tube to obtain the test results; S53: According to the test results, optimize the drive circuit parameters, including the drive current and the gate resistance.

7. The thyristor dimming control method according to claim 1, characterized in that: The method of dynamically adjusting the duty cycle of the PWM signal according to user needs or external dimming signals and optimizing the dimming curve to ensure that the PWM signal frequency is high enough at low brightness, reduce flickering, and achieve smooth brightness adjustment from 0% to 100% includes the following steps: S61: according to dimming requirements, setting a dimming curve, such as a linear, exponential or logarithmic curve, to achieve different dimming effects; S62: Test the dimming effect at different brightness settings; S63: Monitor the stability of the dimming system under long-term operation conditions and record brightness changes and abnormal phenomena; S64: According to the test and evaluation results, adjust the PWM signal parameters, including the frequency and duty cycle, and adjust the drive current parameters.

8. A thyristor dimming control system, applied to a thyristor dimming control method as claimed in any one of claims 1 to 7, characterized in that: include: The power management module provides a stable power supply for the entire dimming system, including a small DC-DC converter circuit to convert the input power into the stable 5V voltage required by the system; The phase detection and control module uses a phase detection chip to monitor the zero-crossing point of the AC input voltage to determine the phase, and adjusts the trigger point of the PWM signal based on the detected phase information to ensure that the PWM signal is synchronized with the phase of the AC power supply; The PWM signal generation and dimming control module generates a PWM signal that is phase-synchronized with the input voltage based on the phase detection result, and adjusts the duty cycle of the PWM signal according to a preset dimming curve to achieve smooth dimming; The signal isolation and driving module isolates the PWM signal generated by the microcontroller from the subsequent circuit.

9. An electronic device, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of a thyristor dimming control method as described in any one of claims 1 to 7 when executing the computer program.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of a thyristor dimming control method as described in any one of claims 1 to 7 are implemented.

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