Overcurrent protection method of LLC resonant converter and related device
By collecting and comparing current in real time in the LLC resonant converter, turning off the switch tube in time, and controlling the second power switch tube based on the on-time, the problem of overcurrent protection is solved, and the stability and safety of the converter are improved. Optimized performance.
Patent Information
- Application Number
- CN202411437000.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-15
- Publication Date
- 2025-01-03
AI Technical Summary
The lack of overcurrent protection for LLC resonant converters in the prior art leads to excessive current, damage to the switch tube, reducing reliability and stability, and increasing safety risks.
By collecting current in real time on the primary side of the LLC resonant converter, comparing with the DAC set value, turning off the first power switch tube in time, and controlling the conduction of the second power switch tube based on the conduction time of the first power switch tube. and shutdown, coordinate the work of both.
Effectively avoid component damage caused by excessive current, improve the stability and safety of the converter, optimize performance, and improve reliability and overall performance.
Smart Images
Figure CN119253540A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of semiconductor technology, and in particular to an overcurrent protection method and related device for an LLC resonant converter. Background Art
[0002] LLC resonant converter is a power conversion topology. LLC resonant converter is usually used to achieve efficient high-voltage to low-voltage conversion, such as in power adapters.
[0003] The related art lacks overcurrent protection for LLC resonant converters. Overcurrent protection is an important safety function. Failure to provide overcurrent protection for LLC resonant converters will result in excessive current in the circuit, thereby damaging key components such as the switch tube in the LLC resonant converter, thereby reducing the reliability and stability of the LLC resonant converter, increasing safety risks, and affecting the overall performance of the LLC resonant converter. Summary of the invention
[0004] Based on the above problems, the present application provides an overcurrent protection method and related devices for an LLC resonant converter, which can realize overcurrent protection for the LLC resonant converter to avoid damage to key components such as the switching tube in the LLC resonant converter, thereby improving the reliability and stability of the LLC resonant converter and reducing safety risks.
[0005] The embodiments of the present application disclose the following technical solutions:
[0006] An overcurrent protection method for an LLC resonant converter, the method comprising:
[0007] When the first power switch tube of the target LLC resonant converter is turned on, the switch current of the current acquisition module of the target LLC resonant converter is collected in real time; the current acquisition module is arranged in the primary resonant cavity of the primary side of the target LLC resonant converter; the first power switch tube is the power switch tube that is first turned on on the primary side of the target LLC resonant converter after the target LLC resonant converter is powered on;
[0008] Comparing the switch current with a setting value of a digital-to-analog converter DAC;
[0009] During a resonant period of the target LLC resonant converter, when the switch current is equal to a setting value of the digital-to-analog converter, turning off the first power switch tube;
[0010] The second power switch tube on the primary side of the target LLC resonant converter is controlled to be turned on and off based on the turn-on time of the first power switch tube; the turn-on time of the first power switch tube is the time from when the first power switch tube starts to be turned on to when it is turned off; the second power switch tube is the power switch tube on the primary side of the target LLC resonant converter that is turned on after the first power switch tube after the target LLC resonant converter is powered on.
[0011] In a possible implementation manner, comparing the switch current with a setting value of a DAC includes:
[0012] Inputting the switching current into a target microcontroller unit MCU;
[0013] The setting value of the DAC of the target MCU is compared with the switch current.
[0014] In a possible implementation, the controlling the turning on and off of the second power switch tube on the primary side of the target LLC resonant converter based on the turn-on time of the first power switch tube includes:
[0015] Calculating the on-time of the first power switch tube, and timing the off-time of the first power switch tube;
[0016] When the sum of the on time and the off time of the first power switch tube reaches half of the switch tube on period, the second power switch tube is controlled to be turned on, and the on time of the second power switch tube is recorded; the switch tube on period is the sum of the time from the two power switch tubes on the primary side of the target LLC resonant converter to the time from the two power switch tubes being turned on to the time from the two power switch tubes being turned off in their normal working cycle;
[0017] When the conduction time of the second power switch tube is equal to the conduction time of the first power switch tube, the second power switch tube is turned off.
[0018] In a possible implementation, the target LLC resonant converter includes a full-bridge topology and a half-bridge topology.
[0019] In one possible implementation,
[0020] When the target LLC resonant converter is a full-bridge topology, there are two first power switch tubes and two second power switch tubes;
[0021] When the target LLC resonant converter is a half-bridge topology, there is only one first power switch tube and only one second power switch tube.
[0022] An overcurrent protection device for an LLC resonant converter, the device comprising:
[0023] A collection unit, when the first power switch tube of the target LLC resonant converter is turned on, is used to collect the switching current of the current collection module of the target LLC resonant converter in real time; the current collection module is arranged in the primary resonant cavity of the primary side of the target LLC resonant converter; the first power switch tube is the power switch tube that is first turned on on the primary side of the target LLC resonant converter after the target LLC resonant converter is powered on;
[0024] A first comparing unit, used for comparing the switch current with a setting value of a digital-to-analog converter DAC;
[0025] a first shutoff unit, configured to shut off the first power switch tube when the switch current is equal to a setting value of the digital-to-analog converter during a resonant period of the target LLC resonant converter;
[0026] A first control unit is used to control the turn-on and turn-off of the second power switch tube on the primary side of the target LLC resonant converter based on the turn-on time of the first power switch tube; the turn-on time of the first power switch tube is the time from the start of the first power switch tube to the turn-off; the second power switch tube is the power switch tube on the primary side of the target LLC resonant converter that is turned on after the first power switch tube after the target LLC resonant converter is powered on.
[0027] In a possible implementation manner, the first comparing unit specifically includes:
[0028] An input unit, used for inputting the switching current into a target microcontroller unit MCU;
[0029] The second comparison unit is used to compare the setting value of the DAC of the target MCU with the switching current.
[0030] In a possible implementation manner, the first control unit specifically includes:
[0031] A calculation unit, used to calculate the conduction time of the first power switch tube;
[0032] A timing unit, used to time the turn-off time of the first power switch tube;
[0033] A second control unit, for controlling the second power switch tube to be turned on when the sum of the on time and the off time of the first power switch tube reaches half of the switch tube on period; the switch tube on period is the sum of the time from the two power switch tubes on the primary side of the target LLC resonant converter to the time from the two power switch tubes being turned on to the time from the two power switch tubes being turned off in their normal working cycle;
[0034] A recording unit, used to record the conduction time of the second power switch tube;
[0035] The second shutoff unit is used to shut off the second power switch tube when the on-time of the second power switch tube is equal to the on-time of the first power switch tube.
[0036] An overcurrent protection device for an LLC resonant converter comprises: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the overcurrent protection method for the LLC resonant converter as described above is implemented.
[0037] A computer-readable storage medium stores instructions, and when the instructions are executed on a terminal device, the terminal device executes the overcurrent protection method for the LLC resonant converter as described above.
[0038] Compared with the prior art, this application has the following beneficial effects:
[0039] The present application provides an overcurrent protection method and related device for an LLC resonant converter. Specifically, when the target LLC resonant converter is started, the power input is turned on by first turning on the first power switch tube on its primary side. At the same time, a current acquisition module is provided in the primary resonant cavity on the primary side of the target LLC resonant converter, which is used to monitor and collect the current condition passing through the target LLC resonant converter in real time. The collected switching current signal is then compared with the threshold value pre-set by the DAC. In each resonant cycle of the target LLC resonant converter, once the detected switching current reaches the preset threshold, that is, the specific value determined by the DAC, an instruction will be immediately triggered to turn off the first power switch tube to control the current inflow to minimize, prevent overcurrent, and protect key components from damage. Then, based on the precise calculation and management of the conduction time of the first power switch tube, the subsequent conduction and shutdown time of the second power switch tube are further accurately regulated. The "first" and "second" power switch tubes here are two key components that are turned on in sequence. This approach not only optimizes the power transmission efficiency, but also effectively improves the working stability and safety of the entire converter, ensuring that the system can maintain efficient and reliable operation under different load conditions.
[0040] This application can timely detect and respond to current fluctuations in the circuit by real-time acquisition of the switching current of the current acquisition module and comparison, ensuring effective control of the current within the resonant period. In addition, the on-time of the first power switch tube is used to control the on and off of the second power switch tube, further coordinating the work between the two power switch tubes and improving the efficiency, stability and safety of the LLC resonant converter. Therefore, this application can not only effectively avoid the risk of component damage caused by excessive current, but also optimize the performance of the LLC resonant converter and improve the reliability and overall performance of the LLC resonant converter. BRIEF DESCRIPTION OF THE DRAWINGS
[0041] In order to more clearly illustrate the technical solutions in this embodiment or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0042] Figure 1 A method flow chart of an overcurrent protection method for an LLC resonant converter provided in an embodiment of the present application;
[0043] Figure 2 A primary circuit diagram of a full-bridge topology of an LLC resonant converter provided in an embodiment of the present application;
[0044] Figure 3 A primary circuit diagram of a half-bridge topology of an LLC resonant converter provided in an embodiment of the present application;
[0045] Figure 4 A schematic diagram of the structure of an overcurrent protection device for an LLC resonant converter provided in an embodiment of the present application. DETAILED DESCRIPTION
[0046] To facilitate understanding of the technical solutions provided by the embodiments of the present application, the background technology involved in the embodiments of the present application will be described below.
[0047] LLC resonant converter is a power conversion topology. It achieves efficient energy conversion by using the resonant characteristics of inductors and capacitors. LLC resonant converter combines two inductors (LL) with a capacitor (C) to form a resonant tank.
[0048] There is a lack of overcurrent protection for LLC resonant converters in the related art. Overcurrent protection applied to LLC resonant converters can effectively prevent excessive current in the circuit. If overcurrent protection measures are not implemented for the LLC resonant converter, the current in the circuit may exceed the tolerance range, causing damage to key components such as the switch tube of the LLC resonant converter. In this case, the reliability and stability of the LLC resonant converter will be seriously affected, and even increase safety risks such as fire risk and electric shock hazard. At the same time, the lack of an overcurrent protection mechanism will also affect the overall performance of the LLC resonant converter, leading to problems such as output voltage fluctuations and reduced load adaptability, which in turn affects the normal operation of the LLC resonant converter.
[0049] In order to solve this problem, an overcurrent protection method and related device of an LLC resonant converter are provided in an embodiment of the present application. In the operation of the target LLC resonant converter, when the first power switch tube is turned on, the switch current of the current acquisition module is collected in real time. The current transformer is located on the primary side of the target LLC resonant converter and is set in the primary resonant cavity to ensure accurate monitoring of the current in the circuit. Subsequently, the obtained switch current is compared with the preset value of the DAC). During the resonant period, once it is detected that the switch current is equal to the DAC setting value, the action of closing the first power switch tube is triggered. Finally, the on and off operation of the second power switch tube is controlled based on the on time of the first power switch tube to ensure that the second power switch tube is turned on after the first power switch tube, and the work between the two is effectively coordinated, thereby improving the efficiency, stability and safety of the target LLC resonant converter. By real-time monitoring and comparison of the switch current, the present application can timely identify overcurrent conditions, thereby effectively preventing component damage and improving the safety of the LLC resonant converter.
[0050] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0051] See also Figure 1 , which is a method flow chart of an overcurrent protection method for an LLC resonant converter provided in an embodiment of the present application, such as Figure 1 As shown, the overcurrent protection method of the LLC resonant converter may include steps S101-S104:
[0052] S101: When a first power switch tube of a target LLC resonant converter is turned on, a switch current of a current acquisition module of the target LLC resonant converter is acquired in real time.
[0053] In the target LLC resonant converter, when the first power switch tube is turned on, the switch current of the current acquisition module is collected in real time. The current transformer is located in the primary resonant cavity of the primary side of the target LLC resonant converter, and the first power switch tube is the first switch turned on on the primary side after the target LLC resonant converter is powered on.
[0054] It should be noted that the target LLC resonant converter refers to an LLC resonant converter that performs overcurrent protection.
[0055] In a possible implementation, the current acquisition module may be, but is not limited to, a current transformer, a Hall sensor, a resistor sampling unit, or a resistor + operational amplifier, or even a current signal sampling circuit such as the voltage on a resonant capacitor.
[0056] It should also be noted that the primary resonant cavity of the LLC resonant converter is a resonant circuit composed of inductors and capacitors, which is mainly used to achieve efficient energy conversion and control. It forms a resonant state by adjusting the on and off time of the switch tube, so that the output voltage and current reach the expected level.
[0057] In a possible implementation, the target LLC resonant converter includes a full-bridge topology. When the target LLC resonant converter is a full-bridge topology, there are two first power switch tubes and two second power switch tubes. Figure 2 , Figure 2 A primary circuit diagram of a full-bridge topology of an LLC resonant converter provided in an embodiment of the present application, Figure 2 Q1, Q2, Q3 and Q4 are the power switch tubes of the LLC resonant converter. If Q1 and Q3 are turned on first at the same time, then Q1 and Q3 are the first power switch tubes, and Q2 and Q4 are the second power switch tubes; if Q2 and Q4 are turned on first at the same time, then Q2 and Q4 are the first power switch tubes, and Q1 and Q3 are the second power switch tubes. Figure 2 The CT in it is the current transformer (i.e. the current acquisition module); Cin is the primary input capacitor; Cr is the primary resonant capacitor of the LLC resonant converter, i.e. the C in LLC; Lr is the primary resonant inductor of the LLC resonant converter, i.e. one L in LLC; Lm is the primary inductor of the transformer of the LLC resonant converter, i.e. another L in LLC. Figure 2 The portion within the dashed box is the primary resonant cavity on the primary side of the LLC resonant converter.
[0058] In a possible implementation, the target LLC resonant converter further includes a half-bridge topology. When the target LLC resonant converter is a half-bridge topology, there is only one first power switch tube and one second power switch tube. Figure 3 , Figure 3A primary circuit diagram of a half-bridge topology of an LLC resonant converter provided in an embodiment of the present application, Figure 3 Q1 and Q2 in the figure are power switch tubes of the LLC resonant converter. If Q1 is turned on first, then Q1 is the first power switch tube and Q2 is the second power switch tube; if Q2 is turned on first, then Q2 is the first power switch tube and Q1 is the second power switch tube. Figure 3 The CT in it is the current transformer (i.e., the current acquisition module); Cin is the primary input capacitance of the LLC resonant converter; Cr is the primary resonant capacitance of the LLC resonant converter, i.e., the C in LLC; Lr is the primary resonant inductor of the LLC resonant converter, i.e., one L in LLC; Lm is the primary inductor of the transformer of the LLC resonant converter, i.e., another L in LLC. Figure 3 The portion within the dashed box is the primary resonant cavity on the primary side of the LLC resonant converter.
[0059] S102: Compare the switch current with a setting value of the DAC.
[0060] The collected switch current is compared with the set value of the digital-to-analog converter (DAC) to determine whether the current reaches a predetermined control standard.
[0061] In a possible implementation manner, comparing the switch current with a setting value of a DAC includes:
[0062] The switch current is input into the target microcontroller unit (MCU). Then the setting value of the DAC of the target MCU is compared with the switch current to achieve real-time monitoring and control of the current condition.
[0063] In one possible implementation, the setting value of the DAC can be equal to the ratio of the rated power of the target LLC resonant converter to the input voltage of the input end of the target LLC resonant converter multiplied by 1.2. The present application does not impose any specific restrictions on the size of the setting value of the DAC, and the user can adjust the setting value of the DAC according to actual needs.
[0064] For example, assuming that the rated power of the target LLC resonant converter is 200 watts (W) and the input voltage at the input end of the target LLC resonant converter is 24 volts (V), then the setting value of the DAC can be set to 200w / 24v*1.2=10 amperes (A).
[0065] S103: During a resonant period of the target LLC resonant converter, when the switch current is equal to a setting value of the digital-to-analog converter, turning off the first power switch tube.
[0066] During the resonant cycle of the target LLC resonant converter, when the switch current reaches the value set by the digital-to-analog converter, the system will turn off the first power switch tube to ensure the stability and efficiency of the converter. This control method can effectively adjust the output power to ensure stable output power and avoid overload.
[0067] It should be noted that the resonant period is controlled based on the input voltage and load conditions to achieve optimal working efficiency. Load conditions include full load and no-load conditions. When fully loaded, the resonant period is extended to provide the required power; when no-load or light load, the resonant period is shorter to avoid excessive losses and improve system stability. This dynamic adjustment ensures that the performance of the converter is optimized under different operating conditions. The same is true for the input voltage. A high input voltage often means a high frequency, and thus a shorter resonant period is required; a low input voltage often means a low frequency, and thus a longer resonant period is required.
[0068] S104: Controlling the on and off of the second power switch tube on the primary side of the target LLC resonant converter based on the on time of the first power switch tube.
[0069] By monitoring the on-time of the first power switch tube, the on and off of the second power switch tube on the primary side of the target LLC resonant converter can be controlled. The on-time of the first power switch tube refers to the time period from when it starts to turn on to when it turns off. The second power switch tube is another primary side power switch tube that turns on after the first power switch tube after the target LLC resonant converter is powered on. This control strategy helps to coordinate the operation sequence between the power switch tubes, ensuring that the target LLC resonant converter operates effectively and achieves high-efficiency conversion.
[0070] In a possible implementation, the controlling the turning on and off of the second power switch tube on the primary side of the target LLC resonant converter based on the turn-on time of the first power switch tube includes:
[0071] The conduction time of the first power switch tube is calculated, the conduction of the second power switch tube is controlled, and the conduction time of the second power switch tube is recorded. Then, when the conduction time of the second power switch tube is equal to the conduction time of the first power switch tube, the second power switch tube is turned off.
[0072] In the process of controlling the on and off of the second power switch tube on the primary side of the target LLC resonant converter, it is first necessary to accurately calculate the on time of the first power switch tube. At the same time, it is also necessary to control the opening of the second power switch tube, and at the same time record the on period of the second power switch tube. After that, compare the on time of the first and second power switch tubes. Once it is found that the on time of the two is equal, the second power switch tube is immediately instructed to be turned off.
[0073] It should be noted that the switch tube conduction period is the sum of the time from the two power switch tubes on the primary side of the target LLC resonant converter to the time from the two power switch tubes on their normal working cycle. The second power switch tube and the first power switch tube each account for 50% of the switch tube conduction period.
[0074] Exemplarily, under normal circumstances, the first power switch tube is turned on in the first 50% time period of the switch tube conduction cycle; and the second power switch tube is turned on in the last 50% time period of the switch tube conduction cycle.
[0075] Assuming that an overcurrent occurs at the first 20% of the switch tube conduction cycle, the first power switch tube is only turned on for 20%, and then the first power switch tube is turned off by the overcurrent protection mechanism, and remains turned off until the "first 50% time period of the switch tube conduction cycle" is used up, at which time the second power switch tube is turned on, and the second power switch tube is also turned on for only 20%, and then the second power switch tube is turned off until the current switch tube conduction cycle ends. Then, at the beginning of the next switch tube conduction cycle, normal operation resumes.
[0076] The same conduction time of the first power switch tube and the second power switch tube can prevent the LLC resonant converter from generating magnetic bias to protect the main power device. This precise control mechanism can not only effectively prevent overload and protect circuit components from damage, but also greatly improve the reliability and energy efficiency of the system.
[0077] In addition, this application only describes the overcurrent protection method of a single-phase LLC resonant converter. This method can also be used to perform overcurrent protection of the LLC resonant converter in the control of a multi-phase interleaved LLC resonant converter.
[0078] Based on the contents of S101-S104, it can be known that during the operation of the target LLC resonant converter, when the first power switch tube is turned on, the switch current collected by the current acquisition module is monitored in real time. The current acquisition module is located in the primary resonant cavity on the primary side of the target LLC resonant converter. Among them, the first power switch tube is the power switch tube that is first turned on on the primary side of the target LLC resonant converter after the target LLC resonant converter is powered on. Next, the switch current value is compared with the setting value of the digital analog converter DAC. When the switch current is equal to the DAC setting value, the first power switch tube is turned off within the resonance cycle. Subsequently, based on the on-time of the first power switch tube, the on and off of the second power switch tube is controlled. The on-time of the first power switch tube is the length of time from its start of on-time to its off-time. The second power switch tube is another power switch tube on the primary side after the first power switch tube is turned on. The present application can quickly detect and respond to current fluctuations in the circuit by real-time monitoring and comparison of the switch current of the current acquisition module, thereby achieving effective control of the current within the resonance cycle. In addition, by adjusting the on and off of the second power switch tube according to the on time of the first power switch tube, the work of the two can be better coordinated, thereby improving the efficiency, stability and safety of the LLC resonant converter.
[0079] See also Figure 4 , Figure 4 A schematic diagram of the structure of an overcurrent protection device for an LLC resonant converter provided in an embodiment of the present application. Figure 4 As shown, the overcurrent protection device of the LLC resonant converter includes:
[0080] The acquisition unit 401 is used for real-time acquisition of the switch current of the current acquisition module of the target LLC resonant converter when the first power switch tube of the target LLC resonant converter is turned on; the current acquisition module is arranged in the primary resonant cavity of the primary side of the target LLC resonant converter; the first power switch tube is the power switch tube that is first turned on on the primary side of the target LLC resonant converter after the target LLC resonant converter is powered on;
[0081] A first comparing unit 402, configured to compare the switch current with a setting value of a digital-to-analog converter DAC;
[0082] A first shut-down unit 403, used to shut down the first power switch tube when the switch current is equal to the setting value of the digital-to-analog converter during the resonant period of the target LLC resonant converter;
[0083] The first control unit 404 is used to control the conduction and shutdown of the second power switch tube on the primary side of the target LLC resonant converter based on the conduction time of the first power switch tube; the conduction time of the first power switch tube is the time from the start of conduction to the shutdown of the first power switch tube; the second power switch tube is the power switch tube on the primary side of the target LLC resonant converter that is turned on after the first power switch tube after the target LLC resonant converter is powered on.
[0084] In a possible implementation, the first comparing unit 402 specifically includes:
[0085] An input unit, used for inputting the switching current into a target microcontroller unit MCU;
[0086] The second comparison unit is used to compare the setting value of the DAC of the target MCU with the switching current.
[0087] In a possible implementation, the first control unit 404 specifically includes:
[0088] A calculation unit, used to calculate the conduction time of the first power switch tube;
[0089] A timing unit, used to time the turn-off time of the first power switch tube;
[0090] A second control unit, for controlling the second power switch tube to be turned on when the sum of the on time and the off time of the first power switch tube reaches half of the switch tube on period; the switch tube on period is the sum of the time from the two power switch tubes on the primary side of the target LLC resonant converter to the time from the two power switch tubes being turned on to the time from the two power switch tubes being turned off in their normal working cycle;
[0091] A recording unit, used to record the conduction time of the second power switch tube;
[0092] The second shutoff unit is used to shut off the second power switch tube when the on-time of the second power switch tube is equal to the on-time of the first power switch tube.
[0093] In a possible implementation, the target LLC resonant converter includes a full-bridge topology and a half-bridge topology.
[0094] In one possible implementation,
[0095] When the target LLC resonant converter is a full-bridge topology, there are two first power switch tubes and two second power switch tubes;
[0096] When the target LLC resonant converter is a half-bridge topology, there is only one first power switch tube and only one second power switch tube.
[0097] In addition, an embodiment of the present application also provides an overcurrent protection device for an LLC resonant converter, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the overcurrent protection method for the LLC resonant converter as described above is implemented.
[0098] In addition, an embodiment of the present application further provides a computer-readable storage medium, in which instructions are stored. When the instructions are executed on a terminal device, the terminal device executes the overcurrent protection method of the LLC resonant converter as described above.
[0099] The embodiment of the present application provides an overcurrent protection device for an LLC resonant converter. When the first power switch tube of the target LLC resonant converter is turned on, the acquisition unit 401 is first used to collect the switch current of the current acquisition module of the target LLC resonant converter in real time, and the first comparison unit 402 is used to compare the switch current with the setting value of the digital analog converter DAC. During the resonant period of the target LLC resonant converter, when the switch current is equal to the setting value of the digital analog converter, the first shutoff unit 403 shuts off the first power switch tube. Then, the first control unit 404 is used to control the turn-on and turn-off of the second power switch tube on the primary side of the target LLC resonant converter based on the turn-on time of the first power switch tube. By collecting the switch current of the current acquisition module in real time and comparing it, the present application can timely monitor and respond to the current fluctuation in the circuit and effectively control the current within the resonant period. In addition, the turn-on time of the first power switch tube is used to regulate the operation of the second power switch tube, and coordinate the operation between the two to improve the efficiency, stability and safety of the LLC resonant converter. Therefore, the method can not only effectively prevent excessive current from damaging components, but also optimize system performance and enhance the reliability and overall performance level of the LLC resonant converter.
[0100] The above is a detailed introduction to an overcurrent protection method and related devices for an LLC resonant converter provided by the present application. The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the embodiments can be referenced to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.
[0101] It should be understood that in this application, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements defined by the statement "comprise one..." do not exclude the presence of other identical elements in the process, method, article or equipment including the elements.
Claims
1. An overcurrent protection method for LLC resonant converter, characterized in that: The method comprises: When the first power switch tube of the target LLC resonant converter is turned on, the switch current of the current acquisition module of the target LLC resonant converter is collected in real time; the current acquisition module is arranged in the primary resonant cavity of the primary side of the target LLC resonant converter; the first power switch tube is the power switch tube that is first turned on on the primary side of the target LLC resonant converter after the target LLC resonant converter is powered on; Comparing the switch current with a setting value of a digital-to-analog converter DAC; During a resonant period of the target LLC resonant converter, when the switch current is equal to a setting value of the digital-to-analog converter, turning off the first power switch tube; The second power switch tube on the primary side of the target LLC resonant converter is controlled to be turned on and off based on the turn-on time of the first power switch tube; the turn-on time of the first power switch tube is the time from when the first power switch tube starts to be turned on to when it is turned off; the second power switch tube is the power switch tube on the primary side of the target LLC resonant converter that is turned on after the first power switch tube after the target LLC resonant converter is powered on.
2. The method according to claim 1, characterized in that The comparing the switch current with a setting value of a DAC comprises: Inputting the switching current into a target microcontroller unit MCU; The setting value of the DAC of the target MCU is compared with the switch current.
3. The method according to claim 1, characterized in that The method of controlling the on and off of the second power switch tube on the primary side of the target LLC resonant converter based on the on time of the first power switch tube includes: Calculating the on-time of the first power switch tube, and timing the off-time of the first power switch tube; When the sum of the on time and the off time of the first power switch tube reaches half of the switch tube on period, the second power switch tube is controlled to be turned on, and the on time of the second power switch tube is recorded; the switch tube on period is the sum of the time from the two power switch tubes on the primary side of the target LLC resonant converter to the time from the two power switch tubes being turned on to the time from the two power switch tubes being turned off in their normal working cycle; When the conduction time of the second power switch tube is equal to the conduction time of the first power switch tube, the second power switch tube is turned off.
4. The method according to claim 1, characterized in that: The target LLC resonant converter includes a full-bridge topology and a half-bridge topology.
5. The method according to claim 1, characterized in that When the target LLC resonant converter is a full-bridge topology, there are two first power switch tubes and two second power switch tubes; When the target LLC resonant converter is a half-bridge topology, there is only one first power switch tube and only one second power switch tube.
6. An overcurrent protection device for LLC resonant converter, characterized in that: The device comprises: A collection unit, when the first power switch tube of the target LLC resonant converter is turned on, is used to collect the switching current of the current collection module of the target LLC resonant converter in real time; the current collection module is arranged in the primary resonant cavity of the primary side of the target LLC resonant converter; the first power switch tube is the power switch tube that is first turned on on the primary side of the target LLC resonant converter after the target LLC resonant converter is powered on; A first comparing unit, used for comparing the switch current with a setting value of a digital-to-analog converter DAC; a first shutoff unit, configured to shut off the first power switch tube when the switch current is equal to a setting value of the digital-to-analog converter during a resonant period of the target LLC resonant converter; A first control unit is used to control the turn-on and turn-off of the second power switch tube on the primary side of the target LLC resonant converter based on the turn-on time of the first power switch tube; the turn-on time of the first power switch tube is the time from the start of the first power switch tube to the turn-off; the second power switch tube is the power switch tube on the primary side of the target LLC resonant converter that is turned on after the first power switch tube after the target LLC resonant converter is powered on.
7. The device according to claim 6, characterized in that The first comparison unit specifically includes: An input unit, used for inputting the switching current into a target microcontroller unit MCU; The second comparison unit is used to compare the setting value of the DAC of the target MCU with the switching current.
8. The device according to claim 6, characterized in that The first control unit specifically includes: A calculation unit, used to calculate the conduction time of the first power switch tube; A timing unit, used to time the turn-off time of the first power switch tube; A second control unit, for controlling the second power switch tube to be turned on when the sum of the on time and the off time of the first power switch tube reaches half of the switch tube on period; the switch tube on period is the sum of the time from the two power switch tubes on the primary side of the target LLC resonant converter to the time from the two power switch tubes being turned on to the time from the two power switch tubes being turned off in their normal working cycle; A recording unit, used to record the conduction time of the second power switch tube; The second shutoff unit is used to shut off the second power switch tube when the on-time of the second power switch tube is equal to the on-time of the first power switch tube.
9. An overcurrent protection device for an LLC resonant converter, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the overcurrent protection method for the LLC resonant converter as described in any one of claims 1 to 5 is implemented.
10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores instructions, and when the instructions are executed on a terminal device, the terminal device executes the overcurrent protection method for the LLC resonant converter as described in any one of claims 1 to 5.