System for carrying out thermal management on automobile lamp based on zero-crossing chopping technology

Abstract

The invention relates to the technical field of automobile lamps, and discloses a system for performing thermal management on an automobile lamp based on a zero-crossing chopping technology, which comprises a zero-crossing chopping module, a DC / DC module, an MCU processing unit, a DC / DC module, a DC / DC module, a DC / DC module, a DC / DC module, a DC / DC module, a DC / DC module, a DC / DC module, a DC / DC module, a DC / DC module, a DC / DC module, a DC / DC module, a DC / DC module and an MCU processing unit, and the ripple extraction end of the alternating current superposition module is connected with an alternating current ripple node of the switching power supply module. According to the system for carrying out thermal management on the automobile lamp based on the zero-crossing chopping technology, the digital temperature acquisition module is adopted, a pulse string with a specific width corresponding to the temperature of-40 DEG C to 125 DEG C is output in a 100ms period, an additional analog-digital conversion link is not needed, the anti-interference capability is high, the acquisition precision is high, the real-time temperature of the lamp can be accurately captured in a complex electromagnetic environment of an automobile, and the system is suitable for popularization and application. Reliable data support is provided for thermal management control, so that the risk of temperature detection distortion and lamp LED damage caused by signal interference in traditional NTC analog acquisition is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automobile lamps, in particular to a system for heat management of automobile lamps based on zero-crossing chopping technology. BACKGROUND

[0002] Automobile lamp heat management is based on passive heat dissipation and strengthened by active heat dissipation, and is matched with high-efficiency heat transfer elements and intelligent control. The mainstream solution covers conduction / convection / phase change heat dissipation and system-level optimization, and the core is to stably control the junction temperature of light sources such as LEDs in a safe range (usually ≤125℃).

[0003] In the prior art, NTC thermistors are generally used for temperature collection, and the resistance thereof changes exponentially with temperature. The corresponding output 5V-0.5V analog voltage signal is extremely susceptible to interference from the complex electromagnetic environment of the automobile in the low voltage range, resulting in temperature detection distortion. Moreover, this analog collection method also requires an additional analog-to-digital conversion link, which further increases the risk of distortion and delay in the signal transmission process, so that the processing unit cannot obtain real-time and accurate temperature data of the lamp, thereby causing heat management control failure and hidden dangers of lamp LED damage due to overheating or overcurrent. At the same time, the prior art controls the power of the lamp through PWM dimming or analog voltage regulation. However, PWM dimming will cause obvious light flickering at low frequencies, and when the frequency is increased to 2KHz-25KHz to avoid flickering, strong EMI interference will be generated, affecting the work of electronic components around the automobile. Analog voltage regulation is limited by the PN junction characteristics of LEDs, and a voltage change of only 0.2V will cause a sudden change in current of hundreds of mA. Moreover, the control accuracy is affected by the interference of the whole vehicle, so it is difficult to achieve fine power adjustment, and it is easy to damage the LED elements, which cannot guarantee the stable work of the lamp in the safe temperature range. SUMMARY

[0004] (I) Technical problems solved:

[0005] In view of the deficiencies of the prior art, the present application provides a system for heat management of automobile lamps based on zero-crossing chopping technology, which solves the problems of temperature detection distortion caused by electromagnetic interference of NTC analog temperature collection, flickering or EMI interference of PWM dimming, and sudden change of current damaging LEDs caused by analog voltage regulation, and further causes heat management control failure.

[0006] (II) Technical solutions:

[0007] To achieve the above purpose, the present application is implemented by the following technical solutions: a system for heat management of automobile lamps based on zero-crossing chopping technology, comprising a switching power supply module, an MCU processing unit and a load module, comprising a switching power supply module, an MCU processing unit, a load module and a DC / DC module, comprising:

[0008] Zero-crossing chopper module, power input end connected to the DC / DC module, control end connected to the MCU processing unit, for phase chopping under the control of the processing unit to the input AC;

[0009] AC superposition module, ripple extraction end connected to the AC ripple node of the switching power supply module, chopper signal end connected to the output end of the zero-crossing chopper module to obtain phase-controlled AC, and then superimposed with the constant current part of the control load;

[0010] The power output end of the AC superposition module is connected to the load module;

[0011] The zero-crossing chopper module controls the conduction angle of the AC according to the instructions of the MCU processing unit, and the AC component of the switching power supply module is chopped and power amplified through the zero-crossing chopper module, and then superimposed with the constant current power supply of the switching power supply, and output to the load module after power amplification, thereby realizing continuous adjustment of the working power by adjusting the AC energy superimposed on the DC power supply of the load.

[0012] Preferably, the zero-crossing chopper module includes a zero-crossing output control unit, a zero-crossing signal sampling unit, a chopping execution unit and a resistor R6.

[0013] Preferably, the zero-crossing output control unit includes:

[0014] Current limiting resistor R1, one end connected to the output end of the AC signal after shaping and amplification of the switching circuit;

[0015] Optocoupler U2, the positive electrode of the input side light emitting diode is connected to the current limiting resistor R1, and the negative electrode is connected to the loop end of the AC signal after shaping and amplification;

[0016] The collector terminal of the light-sensitive transistor on the output side of the optocoupler U2 is connected as a power supply end to the power supply VCC, and the base terminal is connected as a zero-crossing trigger signal control end.

[0017] Preferably, the zero-crossing signal sampling unit includes:

[0018] Current limiting resistor R4;

[0019] Resistor R5, one end connected to the emitter terminal of the optocoupler U2;

[0020] Transistor Q2, base connected to the other end of the resistor R2, emitter connected to ground, collector as a zero-crossing trigger signal output end connected to the power supply VCC through the current limiting resistor R4.

[0021] Preferably, the chopping execution unit includes:

[0022] a resistor R3, one end of which is connected to a chopping control pin of the MCU processing unit;

[0023] a transistor Q1, the base of which is connected to the resistor R3, and the emitter of which is connected to ground;

[0024] a resistor R5, one end of which is connected to a power supply VCC;

[0025] an optocoupler U1, the positive electrode of the input side light emitting diode of which is connected to the resistor R5, and the negative electrode of which is connected to the collector of the transistor Q1;

[0026] the optocoupler U1 comprises a bidirectional thyristor at the output side, the first main terminal of the bidirectional thyristor being connected to the AC power supply, and the second main terminal serving as an output terminal of the chopping execution unit.

[0027] Preferably, the MCU processing unit is configured to adjust the conduction angle of the AC power of the zero-crossing chopping module in the range of 180°-360° with a precision of 0.5°, and output a chopping trigger signal through a 16-bit timer within a period of 2.5μs of the switching power supply module, so as to realize trigger control of the conduction angle.

[0028] Preferably, the resistor R6 has one end connected to the first main terminal of the output side bidirectional thyristor of the optocoupler U1, and one end connected to the power output terminal of the zero-crossing chopping module.

[0029] Preferably, the AC superposition module comprises:

[0030] a direct-current blocking capacitor C1, one end of which is connected to the ripple extraction terminal;

[0031] a coupling capacitor C2;

[0032] an operational amplifier U3, the non-inverting input terminal of which is connected to the direct-current blocking capacitor C1, and the output terminal of which is connected to the load module through the coupling capacitor C2;

[0033] a feedback resistor R7, which is connected between the inverting input terminal and the output terminal of the operational amplifier U3;

[0034] a resistor R8, one end of which is connected to the inverting input terminal of the operational amplifier U3, and the other end of which is connected to ground.

[0035] Preferably, the system further comprises:

[0036] a digital temperature acquisition module, the signal output terminal of which is connected to the MCU processing unit, and the MCU processing unit is configured to receive the signal of the digital temperature acquisition module, calculate corresponding control instructions according to the signal, and output the control instructions to the control terminal of the zero-crossing chopping module, and provide temperature feedback for the load power regulation of the AC superposition module.

[0037] Preferably, the switching power supply module is a SEPIC type switching power supply circuit.

[0038] (III) Beneficial effects:

[0039] The system for heat management of automobile lamps based on zero-crossing chopping technology has the following beneficial effects:

[0040] 1. The system for heat management of automobile lamps based on zero-crossing chopping technology adopts a digital temperature acquisition module to output a specific width pulse train corresponding to -40°-125° temperature at a 100ms cycle, without an additional analog-digital conversion link, and has strong anti-interference ability and high acquisition accuracy, can accurately capture the real-time temperature of the lamp in a complex electromagnetic environment of the automobile, and provide reliable data support for heat management control, thereby avoiding the temperature detection distortion and lamp LED damage risk caused by signal interference in traditional NTC analog acquisition.

[0041] 2. The system for heat management of automobile lamps based on zero-crossing chopping technology combines zero-crossing chopping technology and alternating current superposition technology, and the MCU processing unit performs 0.5° precision subdivision adjustment on the conduction angle of the alternating current in the 180°-360° interval, and precisely outputs a trigger signal in a 2.5us main frequency cycle by means of a 16-bit timer, to realize continuous fine adjustment of the load power, avoid the EMII interference in high-frequency PWM dimming and the light flickering problem in low-frequency, solve the damage of current mutation to the LED in analog voltage adjustment, and ensure stable work of the lamp in a safe temperature interval. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 It is a whole connection block diagram of the system of the application;

[0043] Figure 2 It is a circuit principle diagram of the digital temperature acquisition module of the application;

[0044] Figure 3 It is a circuit principle diagram of the switching power supply module of the application;

[0045] Figure 4 It is a circuit principle diagram of the alternating current superposition module of the application;

[0046] Figure 5 It is a circuit principle diagram of the zero-crossing chopping module of the application;

[0047] Figure 6 It is a circuit principle diagram of the load module of the application;

[0048] Figure 7 It is a structure diagram of the MCU processing unit of the application;

[0049] Figure 8 It is a contained relationship block diagram of the zero-crossing chopping module of the application. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0051] Embodiment one

[0052] Reference Figure 1 、 Figures 3 to 8 A system for heat management of automobile lamps based on zero-crossing chopping technology according to a preferred embodiment of the present application will be described in detail below, including a switching power supply module, an MCU processing unit, a load module and a DC / DC module, comprising:

[0053] A zero-crossing chopping module is connected to the DC / DC module at the power input end and connected to the MCU processing unit at the control end, for phase chopping of the input alternating current under the control of the processing unit, and providing a controllable alternating current signal source for subsequent energy regulation by selective conduction of the DC / DC module. And through direct connection with the MCU processing unit, the fast response of the control command is ensured, thereby avoiding the regulation error caused by signal transmission delay.

[0054] An alternating current superposition module is connected to the alternating current ripple node of the switching power supply module at the ripple extraction end, connected to the output end of the zero-crossing chopping module at the chopping signal end to obtain phase-controlled alternating current, and then superimposed with the constant current part for controlling the load, and connected to the load module at the power output end, for power amplification after superimposition of the two alternating current signals extracted from the naturally existing alternating current ripple of the switching power supply, to ensure that the output energy can meet the working requirements of the automobile lamps, and without the need for additional alternating current signal generating devices in the process, thereby reducing the system complexity and cost.

[0055] The power output end of the alternating current superposition module is connected to the load module.

[0056] The zero-crossing chopping module controls the conduction angle of the alternating current according to the instruction of the MCU processing unit, and the alternating current superposition module superimposes the alternating current component of the switching power supply module after chopping and power amplification by the zero-crossing chopping module with the constant current power supply of the switching power supply, to realize continuous regulation of the working power by regulating the alternating current energy superimposed on the load direct current power supply. It realizes smooth change of power through superposition of alternating current energy, which not only ensures the continuity of lamp brightness regulation, but also avoids damage to LED elements caused by current mutation in direct current regulation, and takes into account the regulation accuracy and element protection power control.

[0057] The zero-crossing chopping module includes a zero-crossing output control unit, a zero-crossing signal sampling unit, a chopping execution unit and a resistor R6, which constitute a complete phase chopping control link. The zero-crossing signal sampling unit is responsible for accurately capturing the zero-crossing point signal of the alternating power supply, providing a timing reference for subsequent control. The zero-crossing output control unit shapes, amplifies and logically processes the sampling signal to generate a trigger instruction that meets the control requirements. The chopping execution unit implements accurate on-off control of the alternating power supply near the zero-crossing point according to the trigger instruction, and changes the output power by adjusting the conduction angle.

[0058] The zero-crossing output control unit includes:

[0059] The current-limiting resistor R1 is connected to the output end of the output alternating current signal of the switching circuit after shaping and amplification, thereby avoiding damage to the input side of the optocoupler U2 caused by overloading of the switching circuit output signal, and realizing safe transmission of the signal.

[0060] The optocoupler U2 has its input side light-emitting diode connected to the current-limiting resistor R1, and its negative electrode connected to the loop end of the alternating current signal after shaping and amplification. The optocoupler U2 electrically isolates the alternating current signal on the strong current side from the control circuit on the weak current side through optical isolation, which not only prevents strong current interference from entering the control link, but also improves the electrical safety of the system.

[0061] The collector terminal of the optocoupler U2 output side phototransistor is connected to the power supply VCC as a power supply end, and the base terminal is connected to the zero-crossing trigger signal control end, so that the isolated signal can be converted into a level signal suitable for the subsequent unit, providing a level signal for the generation of the zero-crossing trigger instruction.

[0062] The zero-crossing signal sampling unit includes:

[0063] The current-limiting resistor R4 is used to limit the working current of the collector of the transistor Q2 to ensure stable operation of the device.

[0064] The resistor R5 is connected to the emitter terminal of the optocoupler U2 on one end, and cooperates with the transistor Q2 to complete the secondary shaping and level conversion of the output signal of the optocoupler U2, so that the signal amplitude and timing are more matched to the control requirements of the zero-crossing trigger.

[0065] The transistor Q2 has its base connected to the other end of the resistor R2, its emitter connected to ground, and its collector connected to the power supply VCC through the current-limiting resistor R4 as a zero-crossing trigger signal output end.

[0066] The chopping execution unit includes:

[0067] Resistor R3, one end connected to the MCU processing unit's chopping control pin, as the MCU output signal's current limiting resistor, limits the current flowing into the transistor Q1 base, preventing excessive current from burning out the transistor Q1. At the same time, through reasonable matching of the resistance value, it ensures that the transistor Q1 can be turned on and off quickly and reliably under the control of the MCU output signal.

[0068] Transistor Q1, base connected to resistor R3, emitter connected to ground. It is a primary amplification and driving element for the MCU control signal, used to convert the weak electric control signal output by the MCU into a current signal that can drive the optocoupler U1. Its emitter is connected to ground to form a complete current loop. The on-off state of the optocoupler U1 input side is controlled by the high-low level of the base signal, which in turn controls the optocoupler U1 input side.

[0069] Resistor R5, one end connected to the power supply VCC, used to provide working current for the optocoupler U1 input side LED. When the transistor Q1 is off, the current flows through the LED through the resistor R5, making it emit light and triggering the optocoupler U1 output side triac to conduct. The resistance value of resistor R5 needs to consider the working current demand of the LED and the energy saving requirement, so as to ensure that enough driving current is provided while avoiding unnecessary power consumption.

[0070] Optocoupler U1, input side LED positive connected to resistor R5, negative connected to transistor Q1 collector, used to transmit signals from the low-voltage control side to the high-voltage AC power side, isolate the interference of high and low voltage circuits, and the triac on the output side can withstand the high voltage of the AC power supply and the load current, providing reliable power execution elements for subsequent phase chopping.

[0071] Optocoupler U1 includes output side triac, the first main terminal of the triac is connected to the AC power supply, and the second main terminal is the output end of the chopping execution unit. As a non-contact switching element, the triac has the advantages of fast response speed, long service life, and no mechanical wear, and can realize conduction and shutdown control in both positive and negative half cycles of the AC power supply, thus adapting to the characteristics of AC power. And its connection mode with the AC power supply and the subsequent module can ensure that the phase-controlled AC power after chopping can be directly output to the AC superposition module, thereby providing stable input for energy superposition.

[0072] Resistor R6, one end connected to the first main terminal of the optocoupler U1 output side triac, and the other end connected to the power output end of the zero-crossing chopping module. Resistor R6 is located between the optocoupler U1 triac and the power output end of the zero-crossing chopping module, which can realize reliable transmission of phase-controlled AC power, and can also suppress electromagnetic interference and voltage spikes through its own impedance to protect core devices. Moreover, its stable characteristics can avoid signal transmission deviation and ensure the 0.5° precision of the MCU.

[0073] The following is the entire working process and working principle of the above embodiment:

[0074] After the system is started, the digital temperature acquisition module first acquires the real-time temperature of the automobile lamp load module, and outputs a specific width pulse train corresponding to the temperature of-40°-125° at a period of 100 ms. Without an additional analog-digital conversion link, the temperature digital signal with strong anti-interference and high precision is directly transmitted to the MCU processing unit. After receiving the temperature signal, the MCU processing unit quickly calculates and generates corresponding control instructions and outputs them to the control end of the zero-crossing chopping module. At the same time, the zero-crossing output control unit accesses the shaped and amplified alternating current signal through the current limiting resistor R1, and realizes electrical isolation between the strong and weak sides through the optocoupler U2, so as to avoid strong electrical interference from entering the control link and safely transmit the isolated signal to the zero-crossing signal sampling unit. The zero-crossing signal sampling unit collects the output signal of the optocoupler U2 through the resistor R5, and outputs an accurate zero-crossing trigger signal after shaping by the transistor Q2 and level adjustment by the current limiting resistor R4. The zero-crossing trigger signal and the control instructions of the MCU jointly act on the chopping execution unit, which accurately controls the on-off of the power device near the zero-crossing point of the alternating current power supply according to the signal, changes the output power by adjusting the conduction angle of the alternating current, and the resistor R6 suppresses electromagnetic interference and voltage spikes through its own impedance to protect the stable operation of the power device. Finally, the phase-controlled alternating current output by the zero-crossing chopping module and the alternating current ripple of the switching power supply module are superimposed through the alternating current superimposition module, power amplified, accurately input into the automobile lamp load, and continuously and finely adjusted to realize the continuous and fine adjustment of the working power of the lamp, so as to ensure the stable operation of the lamp in the safe temperature range.

[0075] Embodiment two

[0076] Reference Figures 1 to 8 The MCU processing unit is configured to adjust the conduction angle of the alternating current of the zero-crossing chopping module in the range of 180°-360° with a precision of 0.5°, and output the chopping trigger signal through a 16-bit timer within the period of 2.5 μs of the main frequency of the switching power supply module to realize trigger control of the conduction angle. Among them, the subdivision adjustment precision of 0.5° is greatly improved compared with the traditional control method, which can realize the micro-continuous change of the load power, so as to ensure the smoothness of the brightness adjustment of the automobile lamp and avoid obvious brightness jump. The cooperation of the 16-bit timer and the 2.5 μs main frequency can ensure that the output delay of the chopping trigger signal is extremely small, so as to accurately capture the zero-crossing time of the alternating current, and further control the conduction angle control error in a very small range. So that the lamp can adjust the power in real time according to the temperature change, and avoid damage caused by high temperature or power fluctuation of the lamp.

[0077] The alternating current superimposition module comprises:

[0078] The direct-current capacitor C1 has one end as a ripple extraction end and is used for isolating the direct-current component in the output of the switching power supply, that is, only allowing the alternating current ripple signal to pass, ensuring the purity of the extracted signal and avoiding the interference of the direct-current component on the subsequent alternating current superposition process. At the same time, the capacitance value of the capacitor needs to be matched with the frequency of the alternating current ripple, so that the alternating current ripple signal can pass through efficiently and provide high-quality input signals for energy superposition.

[0079] The coupling capacitor C2 is used for isolating the direct-current potential inside the alternating current superposition module from the direct-current power supply potential of the load module, preventing the direct-current potential of different modules from affecting each other and causing abnormal operation of the circuit. At the same time, the coupling capacitor C2 also transmits the superimposed alternating current power signal to the load module. The capacitance value of the coupling capacitor C2 needs to be optimized according to the output power and the signal frequency, so as to ensure that the transmission loss of the alternating current signal is minimized and the load end can obtain sufficient alternating current energy.

[0080] The operational amplifier U3 has the same phase input end connected to the direct-current capacitor C1 and the output end connected to the load module through the coupling capacitor C2, which is used for linearly superimposing the alternating current ripple signal input by the direct-current capacitor C1 and the phase-controlled alternating current input by the zero-crossing chopping module, and amplifying the superimposed signal to a power level that can drive the load module to work. The connection mode of the same phase input end of the operational amplifier U3 can ensure the high impedance characteristic of the signal input, reduce the load impact on the previous stage circuit, and the driving capability of the output end can be ensured to meet the power demand of the automobile lamp through the specific selection of elements.

[0081] The feedback resistor R7 is connected between the inverse phase input end and the output end of the operational amplifier U3, forming a negative feedback loop. It is used to stabilize the output gain of the operational amplifier U3, avoid the instability of the amplification multiple caused by factors such as power fluctuation and element parameter drift, and ensure the amplitude accuracy of the output signal. At the same time, the negative feedback of the feedback resistor R7 can also improve the waveform distortion of the output signal, making the superimposed alternating current signal more regular and providing stable power input for the load module.

[0082] The resistor R8 has one end connected to the inverse phase input end of the operational amplifier U3 and the other end connected to the ground. It cooperates with the feedback resistor R7 to set the amplification multiple of the operational amplifier U3. By adjusting the resistance ratio of the two resistors, the amplification ratio of the signal can be accurately controlled, so as to meet the adaptation of automobile lamps with different power demands.

[0083] It also includes:

[0084] The digital temperature acquisition module is connected with the MCU processing unit at a signal output end, the MCU processing unit is configured to receive a signal of the digital temperature acquisition module, calculate a corresponding control instruction according to the signal, and output the control instruction to a control end of the zero-crossing chopping module, and provide temperature feedback for the load power regulation of the AC superposition module. Compared with the existing analog temperature acquisition mode, the digital temperature acquisition module has the advantages of strong anti-interference ability and high acquisition precision, and can accurately acquire the real-time temperature of the lamp in the complex electromagnetic environment of the whole vehicle. The digital signal output by the digital temperature acquisition module is directly recognized by the MCU processing unit, without an additional analog-digital conversion link, so that the distortion and delay in the signal transmission process can be reduced. According to the temperature signal and a preset algorithm, the MCU generates a control instruction in real time, so that the conduction angle of the zero-crossing chopping module is accurately matched with the temperature change, a closed-loop thermal management control is formed, and the lamp is ensured to always work in a safe temperature range.

[0085] The switching power supply module is a SEPIC type switching power supply circuit. The SEPIC type switching power supply has the advantages of wide input and output voltage range, can realize step-up and step-down conversion, small output ripple, etc., can adapt to the voltage fluctuation of the automobile power supply system, and provide stable minimum lighting direct current voltage for the lamp. The wide voltage adaptation characteristic can ensure that the power output remains stable under different working conditions such as automobile starting, driving and idling, and the small output ripple can reduce the interference on the AC superposition process, and provide a stable basic direct current power source for fine power regulation.

[0086] The following is the whole working process and working principle of the above embodiment:

[0087] When the automotive lighting is operating, the digital temperature acquisition module captures the LED load temperature in real time through single-line temperature acquisition, outputting a pulse train with a specific width and a 100ms period corresponding to the temperature (e.g., 181-2814 pulses corresponding to -40°C to 125°C). After signal amplification, the stable and reliable digital pulse train signal is transmitted to the MCU processing unit. This process requires no additional analog-to-digital conversion, has strong anti-interference capability, and high acquisition accuracy. After receiving the signal, the MCU processing unit uses an algorithm to subdivide the AC conduction angle of the zero-crossing chopper module within the 180°-360° range with a precision of 0.5°. Simultaneously, it detects the AC zero-crossing point. Within the 2.5μs cycle of the SEPIC type switching power supply circuit (output constant minimum lighting voltage, output capability 3A±0.2A, voltage ripple less than 0.2V, containing both AC and DC components before filtering, with total AC ripple controlled within 0.5V), a chopper trigger signal is output through a 16-bit timer. In the zero-crossing chopper module, the zero-crossing output control unit, through current-limiting resistor R1 and optocoupler U2, accurately captures the zero-crossing moment of the AC power and isolates high-voltage interference, providing a reference for 0.5° precision conduction angle adjustment. The zero-crossing signal sampling unit, through resistor R2, transistor Q2, and current-limiting resistor R4, outputs a regular square wave signal to ensure synchronous triggering of the 16-bit timer. The chopper execution unit, driven by the high-precision control signal of the MCU, completes phase chopping through resistors R3 and R5, transistor Q1, and optocoupler U1 with bidirectional thyristor, matching the 2.5μs main frequency of the SEPIC type switching power supply. The RC buffer circuit suppresses voltage spikes and protects the bidirectional thyristor to adapt to complex automotive operating conditions. The AC superposition module uses DC blocking capacitor C1 to extract the AC ripple component of the switching power supply. Operational amplifier U3 linearly superimposes this component with the phase-controlled AC power output from the zero-crossing chopper module and amplifies the power. Feedback resistors R7 and R8 work together to stabilize the amplification factor and improve waveform distortion. Coupling capacitor C2 isolates the DC potential and transmits the superimposed AC power signal to the LED load. Ultimately, the LED load achieves continuous and precise power adjustment under the combined action of the constant voltage provided by the switching power supply and the controllable AC chopper voltage output by the AC superposition module. This ensures that the lamp operates within a safe temperature range, avoiding both light flicker and EMI interference issues, and preventing damage to LED components from sudden current changes, thus achieving efficient and precise thermal management.

[0088] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A system for thermal management of automotive lighting based on zero-crossing chopping technology, comprising a switching power supply module, an MCU processing unit, a load module, and a DC / DC module, characterized in that, include: The zero-crossing chopper module has its power input terminal connected to the DC / DC module and its control terminal connected to the MCU processing unit. It is used to perform phase chopping on the input AC power under the control of the processing unit. The AC superposition module has its ripple extraction terminal connected to the AC ripple node of the switching power supply module and its chopping signal terminal connected to the output terminal of the zero-crossing chopping module to obtain phase-controlled AC power, which is then superimposed on the constant current portion of the control load. The power output terminal of the AC superposition module is connected to the load module; The zero-crossing chopper module controls the conduction angle of the AC power according to the instructions of the MCU processing unit. The AC superposition module superimposes the AC component of the switching power supply module after chopping and power amplification by the zero-crossing chopper module with the constant current power supply of the switching power supply, and outputs it to the load module after power amplification. By adjusting the AC energy superimposed on the DC power supply of the load, the operating power of the load can be continuously adjusted.

2. The system for thermal management of automotive lighting based on zero-crossing chopping technology according to claim 1, characterized in that: The zero-crossing chopper module includes a zero-crossing output control unit, a zero-crossing signal sampling unit, a chopper execution unit, and a resistor R6.

3. The system for thermal management of automotive lighting based on zero-crossing chopping technology according to claim 1, characterized in that: The zero-crossing output control unit includes: The current-limiting resistor R1 is connected at one end to the output terminal of the AC signal from the switching circuit after it has been shaped and amplified. Optocoupler U2 has its input-side LED with the positive terminal connected to the current-limiting resistor R1 and the negative terminal connected to the circuit terminal of the AC signal after shaping and amplification. The collector terminal of the phototransistor on the output side of the optocoupler U2 is connected to the power supply VCC as the power supply terminal, and its base terminal is used as the zero-crossing trigger signal control terminal.

4. A system for thermal management of automotive lighting based on zero-crossing chopping technology according to claim 3, characterized in that: The zero-crossing signal sampling unit includes: Current-limiting resistor R4; Resistor R5 is connected at one end to the emitter terminal of the optocoupler U2; Transistor Q2 has its base connected to the other end of resistor R2, its emitter grounded, and its collector connected to the power supply VCC via the current-limiting resistor R4 as a zero-crossing trigger signal output terminal.

5. A system for thermal management of automotive lighting based on zero-crossing chopping technology according to claim 2, characterized in that: The chopper execution unit includes: Resistor R3 is connected at one end to the chopper control pin of the MCU processing unit; Transistor Q1 has its base connected to resistor R3 and its emitter grounded. Resistor R5, one end is connected to power supply VCC; Optical coupler U1 has its input-side LED anode connected to resistor R5 and its cathode connected to the collector of transistor Q1. The optocoupler U1 includes a bidirectional thyristor on the output side. The first main terminal of the bidirectional thyristor is connected to the AC power supply, and the second main terminal serves as the output terminal of the chopper execution unit.

6. A system for thermal management of automotive lighting based on zero-crossing chopping technology according to claim 5, characterized in that: The MCU processing unit is configured to adjust the AC conduction angle of the zero-crossing chopper module with a precision of 0.5° in the range of 180°-360°, and to output a chopper trigger signal through a 16-bit timer within the 2.5μs cycle of the main frequency of the switching power supply module, thereby realizing the trigger control of the conduction angle.

7. A system for thermal management of automotive lighting based on zero-crossing chopping technology according to claim 5, characterized in that: One end of the resistor R6 is connected to the first main terminal of the bidirectional thyristor on the output side of the optocoupler U1, and the other end is connected to the power output terminal of the zero-crossing chopper module.

8. A system for thermal management of automotive lighting based on zero-crossing chopping technology according to claim 1, characterized in that: The AC overlay module includes: The DC blocking capacitor C1 has one end as the ripple extraction terminal; Coupling capacitor C2; Operational amplifier U3 has its non-inverting input terminal connected to the DC blocking capacitor C1, and its output terminal connected to the load module through the coupling capacitor C2. Feedback resistor R7 is connected between the inverting input terminal and the output terminal of the operational amplifier U3; Resistor R8 is connected at one end to the inverting input terminal of the operational amplifier U3, and at the other end to ground.

9. A system for thermal management of automotive lighting based on zero-crossing chopping technology according to claim 1, characterized in that, Also includes: The digital temperature acquisition module has its signal output terminal connected to the MCU processing unit. The MCU processing unit is configured to receive the signal from the digital temperature acquisition module, calculate the corresponding control command based on the signal, output it to the control terminal of the zero-crossing chopper module, and provide temperature feedback for the AC superposition module to perform load power adjustment.

10. A system for thermal management of automotive lighting based on zero-crossing chopping technology according to claim 1, characterized in that: The switching power supply module is a SEPIC type switching power supply circuit.

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