A three-phase linear direct drive circuit and a lamp

Abstract

The utility model discloses a three -phase linear direct drive circuit and lamps and lanterns, including rectifier module, light modulation and toning control module, cold light linear constant current direct drive circuit and warm light linear constant current direct drive circuit. Rectifier module converts three -phase alternating current into pulsating direct current, and light modulation and toning control module generates two independent PWM signals according to the received control signal, and cold light and warm light linear constant current direct drive circuit respectively according to two PWM signals constant current linear direct drive corresponding LED and adjust brightness, realize target color temperature through mixed light. The utility model solves the technical problem of traditional scheme's serious frequency flicker, high electromagnetic interference, low three -phase compatibility and short life.

Description

Technical Field

[0001] This utility model relates to the field of LED lighting technology, and in particular to a three-phase linear direct drive circuit and a lamp. Background Technology

[0002] LEDs, as a new generation of green lighting source, have become the mainstream in lighting due to their high efficiency, energy saving, long lifespan, and environmental friendliness. However, their current-driven characteristics require dedicated drive circuits to provide precise constant current control. Among the current mainstream drive technologies, switching solutions, while highly efficient, suffer from complex circuitry, high electromagnetic interference, and low reliability. Linear solutions, with their simple structure, face issues of low efficiency, poor power factor, and severe flicker. Traditional single-phase drive technology suffers from flickering that is imperceptible to the human eye but harmful to health due to 100Hz rectification pulsation, and the reliance on large-capacity electrolytic capacitors for filtering limits the system lifespan to several thousand hours, far below the 50,000-hour lifespan of LED light sources. While three-phase drive technology offers advantages in power density, existing solutions still face high costs and low reliability due to the complex three-phase PFC rectification and DC-DC conversion structure, as well as complex constant power control algorithms in linear solutions. Furthermore, existing technologies, due to poor electromagnetic compatibility, high-frequency switching noise interference, and high costs, struggle to meet the comprehensive requirements of modern lighting systems for flicker-free operation, long lifespan, and high reliability. Therefore, there is an urgent need for a three-phase linear direct drive circuit with flicker-free output, low electromagnetic interference, high three-phase compatibility, and long lifespan. Utility Model Content

[0003] The main purpose of this invention is to propose a three-phase linear direct drive circuit, which aims to solve the technical problems of severe flicker, high electromagnetic interference, low three-phase compatibility and short lifespan of existing LED lamps.

[0004] To achieve the above objectives, the first aspect of this utility model proposes a three-phase linear direct-drive circuit, including a rectifier module, a dimming and color-tuning control module, a cold light linear constant current direct-drive circuit, and a warm light linear constant current direct-drive circuit. The input terminal of the rectifier module is connected to three-phase AC power and converted into pulsating DC power output. The dimming and color-tuning control module includes a dimming and color-tuning control chip. The first input terminal of the dimming and color-tuning control chip is connected to the output terminal of the rectifier module to obtain operating power, and generates two independent PWM signals based on the received control signal. The first input terminal of the cold light linear constant current direct-drive circuit is connected to the output terminal of the rectifier module, and the second input terminal is connected to the first output terminal of the dimming and color-tuning control chip. It drives the cold light LED with constant current based on the first PWM signal and adjusts its brightness. The first input terminal of the warm light linear constant current direct-drive circuit is connected to the output terminal of the rectifier module, and the second input terminal is connected to the second output terminal of the dimming and color-tuning control chip. It drives the warm light LED with constant current based on the second PWM signal and adjusts its brightness. The target color temperature is adjusted by mixing cold light and warm light.

[0005] Preferably, it also includes a three-phase thyristor dimming module, the input of which is connected to a three-phase AC mains power supply, and the output of which is connected to the input of the rectifier module; the three-phase thyristor dimming module outputs an AC voltage with an adjustable phase angle, and the dimming and color-adjusting control chip identifies the phase angle change by detecting the change in the pulsating DC waveform output by the rectifier module, and adjusts the duty cycle of the two PWM signals accordingly, thereby synchronously adjusting the overall brightness of the cold light LED and the warm light LED.

[0006] Preferably, the three-phase thyristor dimming module includes three identical dimming circuits, each corresponding to a one-phase input line; each dimming circuit includes a bidirectional thyristor, a bidirectional trigger diode, and an adjustable resistor; the first control electrode of the bidirectional thyristor is connected to the first terminal of the adjustable resistor and the phase input terminal, the gate of the bidirectional thyristor is connected to the first terminal of the bidirectional trigger diode, and the second terminal of the adjustable resistor is connected to the second terminal of the bidirectional trigger diode.

[0007] Preferably, each phase dimming sub-circuit of the three-phase thyristor dimming module further includes a buffer absorption network, the buffer absorption network including a filter resistor and a filter capacitor; the first end of the filter resistor is connected to the first control electrode of the bidirectional thyristor, the second end is connected to the first end of the filter capacitor, and the second end of the filter capacitor is connected to the second control electrode of the bidirectional thyristor.

[0008] Preferably, each phase dimming circuit of the three-phase thyristor dimming module further includes a surge protection circuit, which includes a transient voltage suppression diode and a fuse; the transient voltage suppression diode is connected across the first and second control electrodes of the bidirectional thyristor to suppress transient overvoltage; the fuse is connected in series in the phase input line to cut off the circuit in case of overcurrent.

[0009] Preferably, it also includes a constant voltage circuit; the input terminal of the constant voltage circuit is connected to the output terminal of the rectifier module, and the output terminal is connected to the first input terminal of the dimming and color-tuning control chip, for converting the pulsating DC power output by the rectifier module into a stable DC voltage and powering the dimming and color-tuning control chip.

[0010] Preferably, the constant voltage circuit includes a constant voltage driver chip, a power inductor, a first diode, a second diode, a first capacitor, a second capacitor, and a third capacitor; the first input terminal of the constant voltage driver chip and the first terminal of the first capacitor are connected to the output terminal of the rectifier module, and the second input terminal is connected to the cathode of the first diode and the first terminal of the second capacitor; the ground terminal of the constant voltage driver chip is connected to the second terminal of the second capacitor, the first terminal of the power inductor, and the cathode of the second diode; the anode of the first diode is connected to the first terminal of the third capacitor and the second terminal of the power inductor, serving as the positive terminal of the constant voltage circuit output; the second terminal of the first capacitor, the anode of the second diode, and the second terminal of the third capacitor are grounded.

[0011] Preferably, the rectifier module includes a first rectifier circuit and a second rectifier circuit; the input terminal of the first rectifier circuit and the input terminal of the second rectifier circuit are connected in parallel to the output terminal of the three-phase thyristor dimming module; the output terminal of the second rectifier circuit is connected to the first input terminal of the cold light linear constant current direct drive circuit, the first input terminal of the warm light linear constant current direct drive circuit, and the input terminal of the constant voltage circuit; the output terminal of the first rectifier circuit is connected to the second input terminal of the dimming and color tuning control chip.

[0012] Preferably, both the first rectifier circuit and the second rectifier circuit are three-phase full-bridge rectifier circuits.

[0013] The second aspect of this utility model provides a lamp, including a three-phase linear direct drive circuit as described in any one of the first aspects.

[0014] This invention proposes a three-phase linear direct-drive circuit and a lighting fixture. By using a three-phase rectified direct-drive output to deliver high-frequency pulsating DC, it completely eliminates the flickering phenomenon of traditional single-phase circuits, solving the problems of visual fatigue and camera flicker interference. The linear constant-current drive circuit, with its electrolytic capacitor-free design, avoids the short lifespan of traditional drive circuits, significantly extending their lifespan. Through dual-channel phase-synchronous PWM control technology, combined with independent constant-current drives for cool and warm light, it achieves high-precision stepless mixing and adjustment of brightness and color temperature. The three-phase rectified direct-drive architecture eliminates the traditional switching power supply conversion stage, improving system efficiency. Integrated control via a dimming and color-tuning chip simplifies the circuit structure, reduces electromagnetic interference, and enhances electromagnetic compatibility and cost advantages.

[0015] Furthermore, this invention achieves stepless dimming in accordance with traditional operating habits through three-phase thyristor phase angle adjustment; completely eliminates flicker and improves visual comfort through PWM duty cycle synchronous control technology; improves the consistency and balance of dimming operation in each phase through a three-phase symmetrical dimming circuit structure; achieves reliable phase angle control through the combination of bidirectional thyristors and trigger diodes; improves the precision of brightness control and user experience through stepless adjustment of adjustable resistors; suppresses thyristor turn-off overvoltage through a buffer absorption network, improving system stability and device reliability; improves electromagnetic compatibility and anti-interference capability by filtering out high-frequency oscillation signals; improves system surge protection capability by suppressing diode fast clamping overvoltage through transient voltage suppression; and improves circuit safety and fault tolerance by timely disconnecting overcurrent circuits through a fuse. The system offers enhanced protection capabilities; provides a stable DC power supply through a constant voltage circuit, improving the stability and anti-interference capabilities of the control chip; enhances system energy utilization and overall reliability through an efficient voltage conversion mechanism; improves voltage conversion efficiency and reduces energy consumption through efficient switching and LC filtering design; provides a clean and stable DC power supply through a multi-stage capacitor filter network, improving system anti-interference capabilities; optimizes circuit operation stability and reliability through optimized component layout and heat dissipation paths; separates power and signal paths through dual rectifier circuits, improving system anti-interference capabilities and stability; optimizes energy distribution through independent power supply design, improving control accuracy and response speed; reduces single-path load through parallel rectifier structure, improving system reliability and lifespan; and achieves efficient energy conversion through a three-phase full-bridge rectifier circuit, improving overall system energy efficiency.

[0016] In summary, this utility model solves the technical problems of severe flickering, high electromagnetic interference, low three-phase compatibility, and short lifespan of existing LED lamps. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0018] Figure 1 A circuit principle block diagram of a three-phase linear direct drive circuit provided in an embodiment of this utility model; Figure 2 A circuit principle block diagram of another three-phase linear direct drive circuit provided in an embodiment of this utility model; Figure 3 A circuit diagram of a rectifier module and a cold / warm optical linear constant current direct drive circuit provided in an embodiment of this utility model; Figure 4 A circuit schematic diagram of a first rectifier circuit provided in an embodiment of the present invention; Figure 5 A circuit diagram of a constant voltage circuit provided in an embodiment of this utility model; Figure 6 A circuit diagram of a dimming and color-tuning control module provided in an embodiment of this utility model; Figure 7 The circuit diagram of a three-phase thyristor dimming module provided in one embodiment of this utility model.

[0019] In the attached diagram: 1-rectifier module, 11-first rectifier circuit, 12-second rectifier circuit, 2-dimming and color-adjusting control module, 3-cold light linear constant current direct drive circuit, 4-warm light linear constant current direct drive circuit, 5-three-phase thyristor dimming module, 6-constant voltage circuit.

[0020] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0022] It should be noted that if the embodiments of this utility model involve directional indicators, such as up, down, left, right, front, back, etc., the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0023] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0024] The main purpose of this invention is to propose a three-phase linear direct drive circuit, which aims to solve the technical problems of poor lightning protection, severe flicker, high electromagnetic interference, low three-phase compatibility and short lifespan of existing LED lamps.

[0025] like Figures 1 to 7 As shown, this utility model proposes a three-phase linear direct-drive circuit, including a rectifier module 1, a dimming and color-tuning control module 2, a cold-light linear constant-current direct-drive circuit 3, and a warm-light linear constant-current direct-drive circuit 4. The input terminal of the rectifier module 1 is connected to three-phase AC power. In this embodiment, the rectifier module 1 is a three-phase full-bridge topology used to convert AC power into 300Hz pulsating DC power. The dimming and color-tuning control module includes a dimming and color-tuning control chip U4, model MC32F7073. The first input terminal VCC pin of the dimming and color-tuning control chip U4 is connected to the output terminal of the rectifier module 1 through a voltage divider resistor network (not shown in the figure; those skilled in the art can adjust the settings according to the chip used and the voltage connected) to obtain the working power supply, and generates two independent PWM signals based on the received control signal. The dimming and color-tuning control chip U4 is provided with a control interface (such as...). Figure 6 As shown in pins 12-13, it supports external wireless control modules, light sensors, or manual dimmers to receive external dimming and / or color adjustment commands. The dimming and color adjustment control chip U4 adjusts the duty cycle and output ratio of the two PWM signals according to the type of command received to achieve brightness adjustment and color temperature switching. The cold-light linear constant current direct drive circuit 3 includes a first constant current chip U1, model BP5711EJ. The first input terminal VIN pin of the first constant current chip U1 is connected to the output terminal of the rectifier module 1, and the second input terminal DIM pin is connected to the dimming and color adjustment control chip U4. The first output terminal (pin 7) drives the cold light LED with constant current based on the first PWM signal (PWM_C) and adjusts the brightness of the cold light; the warm light linear constant current direct drive circuit 4 includes a second constant current chip U2, model BP5711EJ. The first input terminal VIN pin of the second constant current chip U2 is connected to the output terminal of the rectifier module 1, and the second input terminal DIM pin is connected to the second output terminal (pin 8) of the dimming and color adjustment control chip U4. It drives the warm light LED with constant current based on the second PWM signal (PWM_W) and adjusts the brightness of the warm light. The target color temperature is generated by mixing cold light and warm light.

[0026] The specific working process is as follows: Three-phase AC power is converted into 300Hz pulsating DC power by rectifier module 1. This provides driving power for the cold light linear constant current direct drive circuit 3 and the warm light linear constant current direct drive circuit 4, and also provides operating power for the dimming and color tuning control chip U4. The dimming and color tuning control chip U4 receives external commands (such as wireless signals, light sensor signals, or manual adjustment signals) through its control interface, and generates two independent PWM signals (PWM_C and PWM_W) after parsing. The first constant current chip U1 adjusts the driving current of the cold light LED according to the duty cycle of the PWM_C signal to achieve cold light brightness adjustment; the second constant current chip U2 adjusts the driving current of the warm light LED according to the duty cycle of the PWM_W signal to achieve warm light brightness adjustment. By independently controlling the brightness ratio of the two LEDs, the target color temperature, which can be continuously adjusted from cold white light to warm white light, is finally generated.

[0027] It should be noted that the 300Hz pulsating DC in this embodiment is the typical output frequency under a 50Hz power grid. The actual circuit design has the ability to adapt to the power grid frequency: when applied to a 60Hz power grid (such as the US standard), the fundamental frequency of the rectifier module output automatically switches to 360Hz. The dimming and color adjustment control chip adjusts the phase detection algorithm in real time through the internal phase-locked loop (PLL) to ensure that the PWM signal is always accurately aligned with the zero-crossing point of the pulsating waveform during synchronous refresh. This adaptive mechanism makes the circuit compatible with global power grid standards (50Hz / 60Hz and others), maintaining flicker-free characteristics and color temperature adjustment accuracy. The core innovation lies in the "rectifier frequency..." The constant relationship of "rate = 6 × grid frequency" and the chip's adaptive synchronous control architecture are not limited by specific frequency values. The rectifier module 1 can use a three-phase full-bridge circuit built with discrete diodes, or a half-bridge rectifier, integrated rectifier module, or other equivalent rectifier circuits. The core is to output pulsating DC power. The cold light and warm light linear constant current direct drive circuits are directly powered by pulsating DC power, abandoning the traditional electrolytic capacitor filtering design. The phase-synchronous PWM signal generated by the dimming and color-tuning control chip U4 precisely controls the LED current waveform, so that the driving current and the pulsating voltage are strictly aligned in phase, thereby achieving frequencyless flashing output and completely eliminating the bottleneck of electrolytic capacitor life.

[0028] Understandably, this embodiment completely eliminates the flickering phenomenon of single-phase drive circuits by combining high-frequency pulsed direct drive with dual-channel phase-synchronous PWM control; effectively improves the lifespan of the drive circuit through the electrolytic capacitor-free design; eliminates the traditional switching power supply conversion stage through the three-phase rectifier direct drive architecture, improving system efficiency; achieves high-precision independent adjustment of cool / warm light brightness through phase synchronization technology, improving color temperature mixing uniformity; and simplifies the circuit through an integrated control chip, improving electromagnetic compatibility and cost advantages.

[0029] Those skilled in the art can make corresponding equivalent improvements based on the application scenario, such as: integrating an ambient light sensor to achieve adaptive color temperature adjustment and dynamically adjusting the mixing ratio of cool / warm light according to the ambient brightness; or using SiC Schottky diodes to replace traditional silicon fast recovery diodes to build a rectifier bridge, reducing conduction losses and improving conversion efficiency; or introducing an ambient temperature sensor to link the PWM duty cycle to achieve temperature-compensated automatic brightness adjustment; or embedding AI algorithms in the dimming and color control chip to automatically generate a color temperature curve according to user habits.

[0030] Preferred, see Figure 2 and Figure 7 In a specific embodiment of this utility model, the three-phase linear direct drive circuit further includes a three-phase thyristor dimming module 5; the input terminal of the three-phase thyristor dimming module 5 is connected to the three-phase AC mains power, and the output terminal is connected to the input terminal of the rectifier module 1; the three-phase thyristor dimming module 5 includes three-phase dimming sub-circuits with identical structures, corresponding to the LA, LB, and LC three-phase inputs respectively, and the phase angle of the AC voltage is adjusted and output through the thyristor; the dimming and color-adjusting control chip U4 detects the waveform phase change of the 300Hz pulsating DC power output from the rectifier module 1, identifies the conduction angle change amplitude, and synchronously adjusts the duty cycle of the two PWM signals to achieve overall brightness adjustment of the cold light and warm light LEDs.

[0031] Understandably, this embodiment uses a three-phase thyristor dimming module to achieve analog adjustment of overall brightness, providing users with a stepless dimming method that conforms to traditional operating habits; it uses a dimming and color temperature control chip to accurately analyze phase angle information and generate a synchronous PWM signal, improving the light sensitivity of the dimming light and completely eliminating visible flicker; by combining analog dimming with digital color temperature adjustment technology, it achieves independent control of brightness and color temperature on a single lamp without interference, enhancing the richness of the user experience.

[0032] Those skilled in the art can make corresponding equivalent improvements based on the application scenario, such as replacing the three-phase independent thyristor dimming circuit with a MOS transistor array controlled by a multi-channel dimming dedicated IC to achieve digital phase angle control; or replacing the dimming signal source from phase detection to an external 0-10V analog signal or DALI digital signal to adapt to different lighting control systems.

[0033] Preferred, see Figure 7 In a specific embodiment of this utility model, the three-phase thyristor dimming module 5 includes three-phase dimming circuits with identical structures, each corresponding to a one-phase input line; each phase dimming circuit includes a bidirectional thyristor, a bidirectional trigger diode, and an adjustable resistor; the first control electrode of the bidirectional thyristor is connected to the first end of the adjustable resistor and the phase line input terminal, the gate of the bidirectional thyristor is connected to the first end of the bidirectional trigger diode, and the second end of the adjustable resistor is connected to the second end of the bidirectional trigger diode.

[0034] Specifically, the three sets of independent and symmetrical sub-circuit structures are as follows: The LA phase-modulation photonic circuit: The three-phase AC LA phase is connected to the first gate of the bidirectional thyristor BTA1 and the first terminal of the adjustable resistor RT1; the second terminal of the adjustable resistor RT1 is connected to resistor R14, then to the first terminal of resistor R16, the first terminal of capacitor C7, and the second terminal of bidirectional trigger diode DB1; the first terminal of the bidirectional trigger diode DB1 is connected to the gate of the bidirectional thyristor BTA1; the second terminals of resistor R16 and capacitor C7 are connected to the second gate of the bidirectional thyristor BTA1. The adjustable resistor RT1 and the fixed resistor R14 form a phase-adjusting RC network, precisely controlling the conduction angle by changing the charging time of C7; the bidirectional trigger diode DB1, together with resistor R16 and capacitor C7, forms a critical conduction trigger, triggering the bidirectional thyristor BTA1 to conduct when the voltage of C7 reaches the threshold of the bidirectional trigger diode DB1.

[0035] The LB phase modulation photonic circuit: The LB phase of the three-phase AC power supply is connected to the first gate of the bidirectional thyristor BTA2 and the first terminal of the adjustable resistor RT2; the second terminal of the adjustable resistor RT2 is connected to resistor R19, then to the first terminal of resistor R25, the first terminal of capacitor C10, and the second terminal of bidirectional trigger diode DB2; the first terminal of the bidirectional trigger diode DB2 is connected to the gate of the bidirectional thyristor BTA2; the second terminals of resistor R25 and capacitor C10 are connected to the second gate of the bidirectional thyristor BTA2. The adjustable resistor RT2 and the fixed resistor R19 form a phase-adjusting RC network, precisely controlling the conduction angle by changing the charging time of C10; the bidirectional trigger diode DB2, together with resistor R25 and capacitor C10, forms a critical conduction trigger, triggering the bidirectional thyristor BTA2 to conduct when the voltage of C10 reaches the threshold voltage of the bidirectional trigger diode DB2.

[0036] LC phase modulation photonic circuit: The three-phase AC LC phase is connected to the first gate of the bidirectional thyristor BTA3 and the first terminal of the adjustable resistor RT3; the second terminal of the adjustable resistor RT3 is connected to resistor R31, then to the first terminal of resistor R32, the first terminal of capacitor C12, and the second terminal of bidirectional trigger diode DB3; the first terminal of the bidirectional trigger diode DB3 is connected to the gate of the bidirectional thyristor BTA3; the second terminals of resistor R32 and capacitor C12 are connected to the second gate of the bidirectional thyristor BTA3. The adjustable resistor RT3 and the fixed resistor R31 form a phase-adjusting RC network, precisely controlling the conduction angle by changing the charging time of C12; the bidirectional trigger diode DB3, together with resistor R32 and capacitor C12, forms a critical conduction trigger, triggering the bidirectional thyristor BTA3 to conduct when the voltage of C12 reaches the threshold of the bidirectional trigger diode DB3.

[0037] The working process is as follows: When the user rotates the multi-function button, the mechanical linkage mechanism synchronously adjusts the three sets of adjustable resistors (RT1-RT3) to change the charging time constant of the RC network; when the voltage of the capacitors (C7 / C10 / C12) rises to the threshold of the bidirectional trigger diodes (DB1-DB3), the trigger signal causes the bidirectional thyristors (BTA1-BTA3) to conduct within the AC half-cycle; the change in conduction angle continuously adjusts the effective value of the output voltage to achieve basic brightness control.

[0038] Understandably, this embodiment improves the synchronization accuracy of the three-phase conduction angle by mechanically adjusting three sets of adjustable resistors; improves the conduction angle control accuracy and phase synchronization by using a bidirectional thyristor and bidirectional trigger diode collaborative triggering mechanism; achieves continuous and precise dimming of the conduction angle over a large angle range by flexibly adjusting the RC time constant through adjustable resistors; reduces thyristor switching losses, improves system reliability, and extends device life by dynamically suppressing commutation overvoltage and turn-off spikes through a buffer absorption network; and improves grid load balance and phase control consistency through a three-phase independent symmetrical topology.

[0039] Those skilled in the art can make corresponding equivalent improvements based on the application scenario, such as: using an integrated buffer module to simplify the absorption network design; or replacing the adjustable resistor with a digital potentiometer to support remote programmable control; or introducing a temperature compensation circuit to automatically correct conduction angle drift; or using a solid-state relay to build a contactless switch to replace the mechanical trigger structure.

[0040] Preferred, see Figure 7 In a specific embodiment of this utility model, each phase dimming sub-circuit of the three-phase thyristor dimming module 5 further includes a buffer absorption network, which includes a filter resistor and a filter capacitor; the first end of the filter resistor is connected to the first control electrode of the bidirectional thyristor, the second end is connected to the first end of the filter capacitor, and the second end of the filter capacitor is connected to the second control electrode of the bidirectional thyristor.

[0041] Specifically, the three independent and symmetrical sub-circuit structures are as follows: The buffer absorption network of the LA phase modulation photonic circuit consists of a series filter resistor R18 and a filter capacitor C8, connected between the first and second control electrodes of the bidirectional thyristor BTA1; the buffer absorption network of the LB phase modulation photonic circuit consists of a series filter resistor R30 and a filter capacitor C11, connected between the first and second control electrodes of the bidirectional thyristor BTA2; and the buffer absorption network of the LC phase modulation photonic circuit consists of a series filter resistor R33 and a filter capacitor C6, connected between the first and second control electrodes of the bidirectional thyristor BTA3.

[0042] Understandably, this embodiment effectively suppresses voltage spikes and electromagnetic interference generated during thyristor commutation through a three-phase symmetrical RC buffer absorption network, thereby improving the system's electromagnetic compatibility and operational stability. By employing a combination of high-voltage ceramic capacitors and high-power metal film resistors, the reliability and lifespan of the absorption circuit are improved. Through the consistent design of three-phase parameters, the dimming characteristics of each phase are ensured to be synchronous and consistent, thereby improving the overall dimming uniformity.

[0043] Those skilled in the art can make corresponding equivalent improvements based on the application scenario. For example, the fixed resistor in the RC snubber network can be replaced with a negative temperature coefficient thermistor (NTC) to achieve temperature compensation; or a common ceramic capacitor can be replaced with a metallized polypropylene film capacitor to improve the withstand voltage and frequency characteristics; or a discrete resistor-capacitor combination can be replaced with an integrated RC snubber module to simplify installation and improve consistency.

[0044] Preferred, see Figure 7 In a specific embodiment of this utility model, each phase dimming circuit of the three-phase thyristor dimming module 5 further includes a surge protection circuit, which includes a transient voltage suppression diode and a fuse. The transient voltage suppression diode is connected across the first and second control electrodes of the bidirectional thyristor to suppress transient overvoltage. The fuse is connected in series in the phase line input line to cut off the circuit in case of overcurrent.

[0045] Specifically, the three independent and symmetrical sub-circuit structures are as follows: the surge protection circuit of the LA phase modulation photonic circuit includes fuse F1 and transient voltage suppression diode TVS1; the surge protection circuit of the LB phase modulation photonic circuit includes fuse F2 and transient voltage suppression diode TVS2; and the surge protection circuit of the LC phase modulation photonic circuit includes fuse F3 and transient voltage suppression diode TVS3.

[0046] Understandably, this embodiment effectively suppresses transient overvoltages caused by lightning or grid operation by setting independent transient voltage suppression diodes in each phase of the three-phase dimming circuit, thereby improving the reliability and safety of the system against surge impacts. By connecting fuses in series in each phase input line, independent overcurrent protection is provided for each phase, preventing the spread of single-phase faults from affecting the overall circuit operation, thus improving the system's fault isolation capability and maintenance convenience. By adopting a three-phase symmetrical and independent protection circuit design, the protection characteristics of each phase are ensured to be consistent, improving the three-phase balance and the overall stability of the system.

[0047] Those skilled in the art can make corresponding equivalent improvements based on the application scenario, such as: replacing the transient voltage suppressor diode (TVS) with a varistor (MOV) to reduce costs and adapt to higher energy surge protection requirements; or replacing ordinary fuses with self-resetting fuses to achieve automatic power restoration after fault clearance; or improving the independent protection circuit of each phase into a three-phase integrated protection module to simplify the layout and improve installation efficiency.

[0048] Preferred, see Figure 2 and Figure 5 In a specific embodiment of this utility model, the three-phase linear direct drive circuit further includes a constant voltage circuit 6; the input terminal of the constant voltage circuit 6 is connected to the output terminal of the rectifier module 1, and the output terminal is connected to the first input terminal VCC pin of the dimming and color-tuning control chip, which is used to convert the pulsating DC power output by the rectifier module 1 into a stable DC voltage and power the dimming and color-tuning control chip.

[0049] Understandably, this embodiment uses a constant voltage circuit to convert the rectified pulsating DC power into a stable DC voltage, providing a clean operating power supply for the control chip and improving the system's ability to resist power grid fluctuations.

[0050] Preferred, see Figure 5In a specific embodiment of this utility model, the three-phase linear direct drive circuit further includes a constant voltage circuit 6. The constant voltage circuit 6 includes a constant voltage drive chip U3, a power inductor T1, a first diode D7, a second diode D8, a first capacitor EC2, a second capacitor C9, and a third capacitor EC3. The constant voltage drive chip U3 is a BP2525F, and the first capacitor EC2 and the third capacitor EC3 are electrolytic capacitors. The first input terminal DRAIN pin of the constant voltage drive chip U3 is connected to the output terminal of the second rectifier circuit 12 via the positive terminal of the first capacitor EC2. The second input terminal VCC pin is connected to the cathode of the first diode D7 and the first terminal of the second capacitor C9. The ground terminal GND pin of the constant voltage drive chip U3 is connected to the second terminal of the second capacitor C9, the first terminal of the power inductor T1, and the cathode of the second diode D8. The anode of the first diode D8 is connected to the positive terminal of the third capacitor EC3 and the second terminal of the power inductor T1, serving as the positive terminal of the output terminal of the constant voltage circuit 6. The negative terminal of the first capacitor EC2, the anode of the second diode D8, and the negative terminal of the third capacitor EC3 are grounded. The working process is as follows: When the second rectifier circuit 12 outputs pulsating DC power, the constant voltage drive chip U3 starts high-frequency switching control through its internal oscillator: the input high voltage is filtered by the first capacitor EC2 to remove high-frequency noise and then connected to the first input terminal DRAIN pin of chip U3; the second input terminal VCC pin of chip U3 forms a stable power supply circuit through the first diode D7 and the second capacitor C9; the power switch T1 is periodically turned on / off under the drive signal. During the on-time, the current is transferred from the input terminal to the output terminal through the power inductor T1, supplying energy to the load and the third capacitor EC3. At the same time, the power inductor T1 stores energy, and the third capacitor EC3 and the resistor R26 form an output filter network to absorb ripple; during the off-time, the power inductor T1 releases energy, and the current continues through the second diode D8 to maintain the continuous output current. The third capacitor EC3 continuously smooths the output voltage ripple, and the second capacitor C9 suppresses the VCC power supply fluctuation of chip U3; finally, the pulsating DC power is efficiently converted into stable low-voltage DC power, providing a clean power supply for the dimming and color-tuning control chip U4. It should be noted that the CS pin of the constant voltage driver chip U3 is connected to the GND pin through resistor R24 ​​for real-time detection of the peak current of the power inductor, realizing cycle-by-cycle overcurrent protection. When the current exceeds the set threshold, the internal MOSFET is immediately turned off to prevent inductor saturation damage. The SEL pin of the constant voltage driver chip U3 is connected to the third resistor voltage divider network, which in this embodiment is resistors R20 and R23, used to set the output voltage value of the constant voltage driver chip U3. The output DC voltage is precisely controlled by adjusting the voltage divider ratio. Those skilled in the art can set it according to actual needs.

[0051] Understandably, this embodiment improves the conversion efficiency from pulsating DC to low-voltage DC through high-frequency switching control technology; improves the energy release efficiency during the off-time period through the collaborative freewheeling design of power inductors and dual diodes; improves ripple suppression capability through the combination of input filtering with the first capacitor and output filtering with the third capacitor; and improves circuit reliability and reduces electromagnetic interference through integrated chip control.

[0052] Those skilled in the art can make corresponding equivalent improvements based on the application scenario, such as: replacing the first / second diode with a Schottky diode to reduce the forward voltage drop; or replacing the voltage divider resistor network with a digital potentiometer to achieve programmable output voltage; or introducing an active filter chip to replace the RC filter unit to optimize ripple suppression; or adding a bleed resistor in parallel with the power inductor to release residual energy during the off-period.

[0053] Preferred, see Figure 2 In a specific embodiment of this utility model, the rectifier module 1 includes a first rectifier circuit 11 and a second rectifier circuit 12; the input terminal of the first rectifier circuit 11 and the input terminal of the second rectifier circuit 12 are connected in parallel to the output terminal of the three-phase thyristor dimming module 5; the output terminal of the second rectifier circuit 12 is connected to the first input terminal (VIN pin of the cold light driving chip U1) of the cold light linear constant current direct drive circuit 3, the first input terminal (VIN pin of the warm light driving chip U2) of the warm light linear constant current direct drive circuit 4, and the input terminal of the constant voltage circuit 6; the output terminal of the first rectifier circuit 11 is connected to the second input terminal 15 pin (VS1 signal) of the dimming and color tuning control chip.

[0054] Understandably, this embodiment completely eliminates the interference of the power circuit on the phase sampling signal through the physical isolation design of dual independent rectifier circuits; improves the detection accuracy of the zero-crossing phase signal through a dedicated signal sampling and rectification channel; avoids false triggering of the control chip caused by large current fluctuations through an independent signal sampling channel, reduces electromagnetic crosstalk, and improves system stability; and achieves fault isolation between the control and drive systems through a separate power supply architecture, thereby improving overall reliability.

[0055] Preferred, see Figure 3 and Figure 4 In a specific embodiment of this utility model, both the first rectifier circuit 11 and the second rectifier circuit 12 are three-phase full-bridge rectifier circuits.

[0056] Specifically, the first rectifier circuit 11 consists of diodes D9, D2, D3, D4, D5, and D6 forming a standard three-phase bridge rectifier structure, with its AC input terminals connected to the three-phase output terminals of the three-phase thyristor dimming module 5. The second rectifier circuit 12 consists of diodes D11, D12, D13, D14, D15, and D16 forming a similar three-phase bridge rectifier circuit, with its AC input terminals connected in parallel to the same three-phase output terminals. The positive and negative terminals of the two rectifier circuits are independent, forming two isolated pulsating DC outputs.

[0057] Understandably, this embodiment uses two independent three-phase full-bridge rectifier circuits to supply power separately, thereby achieving physical isolation between the power path and the control path, improving the system's anti-interference capability and stability; it fully utilizes the three-phase electrical characteristics through the three-phase full-bridge rectifier structure, improving energy conversion efficiency and reducing output ripple; and it builds a standard rectifier topology using discrete components, improving circuit reliability and maintenance convenience.

[0058] Those skilled in the art can make corresponding equivalent improvements based on the application scenario, such as: replacing the rectifier bridge composed of discrete diodes with an integrated rectifier module to simplify installation and improve consistency; or replacing ordinary rectifier diodes with silicon carbide Schottky diodes to reduce conduction losses and temperature rise; or using magnetic isolation technology to construct virtual electrical isolation and transmit phase signals through an isolation amplifier.

[0059] The second aspect of this utility model provides a lamp, including a three-phase linear direct drive circuit as described in any of the first aspects.

[0060] Specifically, the luminaire includes a luminaire housing, a light source module, and a three-phase linear direct drive circuit; the light source module includes cold light LED strings and warm light LED strings connected in parallel; the three-phase linear direct drive circuit is integrated into a circuit mounting cavity inside the luminaire housing, the input terminal of its rectifier module is connected to an external three-phase AC power supply through a terminal block, the output terminal of its cold light linear constant current direct drive circuit is connected to the positive terminal of the cold light LED string through a wire, the output terminal of the warm light linear constant current direct drive circuit is connected to the positive terminal of the warm light LED string through a wire, and the negative terminals of the cold light LED string and the warm light LED string are connected to the output ground of the rectifier module.

[0061] Compared with the prior art, the beneficial effects of this utility model include at least the following: This invention proposes a three-phase linear direct-drive circuit and a lighting fixture. By using a three-phase rectified direct-drive output to deliver high-frequency pulsating DC, it completely eliminates the flickering phenomenon of traditional single-phase circuits, solving the problems of visual fatigue and camera flicker interference. The linear constant-current drive circuit, with its electrolytic capacitor-free design, avoids the short lifespan of traditional drive circuits, significantly extending their lifespan. Through dual-channel phase-synchronous PWM control technology, combined with independent constant-current drives for cool and warm light, it achieves high-precision stepless mixing and adjustment of brightness and color temperature. The three-phase rectified direct-drive architecture eliminates the traditional switching power supply conversion stage, improving system efficiency. Integrated control via a dimming and color-tuning chip simplifies the circuit structure, reduces electromagnetic interference, and enhances electromagnetic compatibility and cost advantages.

[0062] Furthermore, this invention achieves stepless dimming in accordance with traditional operating habits through three-phase thyristor phase angle adjustment; completely eliminates flicker and improves visual comfort through PWM duty cycle synchronous control technology; improves the consistency and balance of dimming operation in each phase through a three-phase symmetrical dimming circuit structure; achieves reliable phase angle control through the combination of bidirectional thyristors and trigger diodes; improves the precision of brightness control and user experience through stepless adjustment of adjustable resistors; suppresses thyristor turn-off overvoltage through a buffer absorption network, improving system stability and device reliability; improves electromagnetic compatibility and anti-interference capability by filtering out high-frequency oscillation signals; improves system surge protection capability by suppressing diode fast clamping overvoltage through transient voltage suppression; and improves circuit safety and fault tolerance by timely disconnecting overcurrent circuits through a fuse. The system offers enhanced protection capabilities; provides a stable DC power supply through a constant voltage circuit, improving the stability and anti-interference capabilities of the control chip; enhances system energy utilization and overall reliability through an efficient voltage conversion mechanism; improves voltage conversion efficiency and reduces energy consumption through efficient switching and LC filtering design; provides a clean and stable DC power supply through a multi-stage capacitor filter network, improving system anti-interference capabilities; optimizes circuit operation stability and reliability through optimized component layout and heat dissipation paths; separates power and signal paths through dual rectifier circuits, improving system anti-interference capabilities and stability; optimizes energy distribution through independent power supply design, improving control accuracy and response speed; reduces single-path load through parallel rectifier structure, improving system reliability and lifespan; and achieves efficient energy conversion through a three-phase full-bridge rectifier circuit, improving overall system energy efficiency.

[0063] In summary, this utility model solves the technical problems of severe flickering, high electromagnetic interference, low three-phase compatibility, and short lifespan of existing LED lamps.

[0064] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the inventive concept of the present utility model using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A three-phase linear direct-drive circuit, characterized in that, include: The rectifier module (1) is connected to a three-phase AC power input terminal and converted into a pulsating DC power output. The dimming and color-tuning control module (2) includes a dimming and color-tuning control chip; the first input terminal of the dimming and color-tuning control chip is connected to the output terminal of the rectifier module (1) to obtain the working power supply, and generates two independent PWM signals based on the received control signal; The cold light linear constant current direct drive circuit (3) has a first input terminal connected to the output terminal of the rectifier module (1) and a second input terminal connected to the first output terminal of the dimming and color adjustment control chip. It drives the cold light LED connected to the cold light linear constant current direct drive circuit (3) based on the first PWM signal and adjusts the brightness. The warm light linear constant current direct drive circuit (4) has a first input terminal connected to the output terminal of the rectifier module (1) and a second input terminal connected to the second output terminal of the dimming and color adjustment control chip. Based on the second PWM signal, it drives the warm light LED connected to the warm light linear constant current direct drive circuit (4) and adjusts its brightness. The target color temperature is adjusted by mixing cold light and warm light.

2. The three-phase linear direct-drive circuit as described in claim 1, characterized in that, It also includes a three-phase thyristor dimming module (5), the input of which is connected to the three-phase AC mains power, and the output is connected to the input of the rectifier module (1); the three-phase thyristor dimming module (5) outputs an AC voltage with an adjustable phase angle, and the dimming and color control chip identifies the phase angle change by detecting the change in the pulsating DC waveform output by the rectifier module (1), and adjusts the duty cycle of the two PWM signals accordingly, thereby synchronously adjusting the overall brightness of the cold light LED and the warm light LED.

3. The three-phase linear direct-drive circuit as described in claim 2, characterized in that, The three-phase thyristor dimming module (5) includes three-phase dimming circuits with identical structures, each corresponding to a three-phase input line; each phase dimming circuit includes a bidirectional thyristor, a bidirectional trigger diode, and an adjustable resistor; the first control electrode of the bidirectional thyristor is connected to the first end of the adjustable resistor and the phase line input terminal, the gate of the bidirectional thyristor is connected to the first end of the bidirectional trigger diode, and the second end of the adjustable resistor is connected to the second end of the bidirectional trigger diode.

4. The three-phase linear direct-drive circuit as described in claim 3, characterized in that, Each phase dimming sub-circuit of the three-phase thyristor dimming module (5) further includes a buffer absorption network, which includes a filter resistor and a filter capacitor. The first end of the filter resistor is connected to the first control electrode of the bidirectional thyristor, and the second end is connected to the first end of the filter capacitor. The second end of the filter capacitor is connected to the second control electrode of the bidirectional thyristor.

5. The three-phase linear direct-drive circuit as described in claim 3, characterized in that, Each phase dimming circuit of the three-phase thyristor dimming module (5) also includes a surge protection circuit, which includes a transient voltage suppression diode and a fuse. The transient voltage suppression diode is connected across the first and second control electrodes of the bidirectional thyristor to suppress transient overvoltage. The fuse is connected in series in the phase line input line to cut off the circuit in case of overcurrent.

6. The three-phase linear direct-drive circuit as described in any one of claims 2 to 5, characterized in that, It also includes a constant voltage circuit (6); the input terminal of the constant voltage circuit (6) is connected to the output terminal of the rectifier module (1), and the output terminal is connected to the first input terminal of the dimming and color-tuning control chip, which is used to convert the pulsating DC power output by the rectifier module (1) into a stable DC voltage and power the dimming and color-tuning control chip.

7. The three-phase linear direct-drive circuit as described in claim 6, characterized in that, The constant voltage circuit (6) includes a constant voltage drive chip, a power inductor, a first diode, a second diode, a first capacitor, a second capacitor, and a third capacitor; the first input terminal of the constant voltage drive chip and the first terminal of the first capacitor are connected to the output terminal of the rectifier module (1), and the second input terminal is connected to the cathode of the first diode and the first terminal of the second capacitor; the ground terminal of the constant voltage drive chip is connected to the second terminal of the second capacitor, the first terminal of the power inductor, and the cathode of the second diode; the anode of the first diode is connected to the first terminal of the third capacitor and the second terminal of the power inductor, serving as the positive terminal of the output terminal of the constant voltage circuit (6); the second terminal of the first capacitor, the anode of the second diode, and the second terminal of the third capacitor are grounded.

8. The three-phase linear direct-drive circuit as described in claim 6, characterized in that, The rectifier module (1) includes a first rectifier circuit (11) and a second rectifier circuit (12); the input terminal of the first rectifier circuit (11) and the input terminal of the second rectifier circuit (12) are connected in parallel to the output terminal of the three-phase thyristor dimming module (5); the output terminal of the second rectifier circuit (12) is connected to the first input terminal of the cold light linear constant current direct drive circuit (3), the first input terminal of the warm light linear constant current direct drive circuit (4) and the input terminal of the constant voltage circuit (6); the output terminal of the first rectifier circuit (11) is connected to the second input terminal of the dimming and color-tuning control chip.

9. The three-phase linear direct-drive circuit as described in claim 8, characterized in that, Both the first rectifier circuit (11) and the second rectifier circuit (12) are three-phase full-bridge rectifier circuits.

10. A lamp, characterized in that, Includes the three-phase linear direct drive circuit as described in any one of claims 1 to 9.

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