A junction temperature control method and system based on SiC devices

Abstract

This invention relates to a junction temperature control method and system based on SiC devices, relating to the field of electronic circuits. The method includes: Step 100: acquiring the junction temperature; Step 101: determining a sudden change threshold based on the junction temperature and acquiring the switching frequency; Step 102: determining the rate of change based on the switching frequency; Step 103: when the rate of change is greater than the sudden change threshold, calculating the difference between the rate of change and the sudden change threshold, and defining it as a sudden change difference value; Step 104: determining a buffer duration based on the sudden change difference value; Step 105: determining an intermediate frequency by combining the buffer duration and the switching frequency; Step 106: generating and sending a frequency buffer command in response to the intermediate frequency. This application improves the stability of SiC device operation and provides junction temperature control for multi-circuit topologies.

Description

Technical Field

[0001] This invention relates to the field of electronic circuits, and in particular to a junction temperature control method and system based on SiC devices. Background Technology

[0002] SiC devices refer to power electronic devices made with silicon carbide as the core semiconductor material.

[0003] In existing technologies, SiC devices are generally used for power conversion, transmission and control in power systems. They are the core devices that replace traditional silicon-based power devices. Compared with traditional silicon-based devices, SiC’s crystal structure and material properties endow the devices with core advantages such as high frequency, high temperature, high voltage and low loss.

[0004] SiC devices are highly sensitive to temperature. When the junction temperature of a SiC device becomes uncontrolled, it can easily lead to permanent drift of device parameters or even device damage. Summary of the Invention

[0005] To improve the operational stability of SiC devices and to control junction temperature in multi-circuit topologies, this invention provides a junction temperature control method and system based on SiC devices.

[0006] In a first aspect, the present invention provides a junction temperature control method based on SiC devices, employing the following technical solution:

[0007] A junction temperature control method based on SiC devices includes:

[0008] Step 100: Collect junction temperature;

[0009] Step 101: Determine the sudden change threshold based on the junction temperature and collect the switching frequency;

[0010] Step 102: Determine the rate of change based on the switching frequency;

[0011] Step 103: When the rate of change is greater than the mutation threshold, calculate the difference between the rate of change and the mutation threshold, and define it as the mutation difference value;

[0012] Step 104: Determine the buffer duration based on the mutation difference;

[0013] Step 105: Determine the intermediate frequency by combining the buffer duration and the switching frequency;

[0014] Step 106: In response to the intermediate frequency generation, a frequency buffer command is sent.

[0015] By adopting the above technical solution, the junction temperature of SiC devices is collected in real time. Based on the junction temperature, an appropriate abrupt change threshold is selected. At the same time, the rate of change is calculated in combination with the switching frequency. When the rate of change exceeds the abrupt change threshold, it is determined that the junction temperature is rising too fast. An appropriate intermediate frequency is determined according to the switching frequency to control the switching frequency to rise gradually. This avoids the junction temperature from fluctuating drastically due to sudden changes in the switching frequency, reduces the impact of junction temperature abrupt changes on the performance of SiC devices, reduces the risk of device damage due to excessive thermal stress, and improves the stability and service life of SiC devices.

[0016] Optional, also includes:

[0017] Step 107: When the buffer duration exceeds the preset delay threshold, determine the delay ratio based on the buffer duration and the preset delay threshold;

[0018] Step 108: Determine the delay error value by combining the delay ratio and the mutation difference;

[0019] Step 109: Determine the compensation power in response to the delay error value, and determine the circuit number based on the buffer duration;

[0020] Step 110: Generate and send a power scheduling command based on the circuit number and compensation power.

[0021] By adopting the above technical solution, the gradual increase of the switching frequency requires a certain buffer time, and the greater the rate of change, the greater the buffer time required. For scenarios where the buffer time exceeds the standard, the degree of exceeding the standard is quantified as a delay error value, thereby accurately matching the frequency required to reduce the compensation power to compensate for the delay error value, thus ensuring that SiC devices can still maintain the rated operating state under complex working conditions and improving the adaptability of the control method.

[0022] Optional, also includes:

[0023] Step 111: When the buffer duration exceeds the preset delay threshold, determine the parallel numbering based on the circuit number;

[0024] Step 112: Retrieve the parallel connection temperature and operating threshold based on the parallel number;

[0025] Step 113: Determine the junction temperature coefficient by combining the parallel junction temperature and the operating threshold;

[0026] Step 114: Determine the junction temperature ratio based on the junction temperature coefficient;

[0027] Step 115: Determine the scheduling ratio in response to the junction temperature ratio;

[0028] Step 116: Calculate the product of the scheduling ratio and the compensation power, and define it as the scheduling power;

[0029] Step 117: In response to the parallel numbering and scheduling power update power scheduling instruction.

[0030] By adopting the above technical solution, under the premise of exceeding the buffer time limit, the parallel junction temperature and working threshold of the parallel circuit are retrieved, thereby quantifying the temperature of the parallel circuit into a junction temperature coefficient. The additional scheduling power of the compensation power undertaken by different parallel circuits is allocated according to the junction temperature coefficient, thereby realizing the coordinated control of multiple parallel circuits, reducing the performance degradation caused by excessively high parallel circuit temperature, and enhancing the operational reliability of the multi-parallel system.

[0031] Optionally, it also includes a multiplexing control method, the multiplexing control method comprising:

[0032] Step 200: When the buffer duration exceeds the preset delay threshold, determine the junction temperature difference by combining the junction temperature and the parallel junction temperature;

[0033] Step 201: Determine the average temperature difference based on the junction temperature difference;

[0034] Step 202: Calculate the difference between the junction temperature difference and the mean temperature difference, and define it as the fluctuation difference value;

[0035] Step 203: When the fluctuation difference does not fall within the preset fluctuation range, determine the fluctuation coefficient based on the fluctuation difference;

[0036] Step 204: Update the scheduling ratio based on the fluctuation coefficient.

[0037] By adopting the above technical solution, in multi-channel control scenarios, the average temperature difference of parallel circuits is calculated by combining junction temperature and parallel junction temperature, thereby identifying parallel circuits with excessively large or small junction temperatures, and adjusting the scheduling ratio according to the junction temperature deviation, thereby ensuring that the junction temperatures of multiple devices are similar and improving the thermal stability and operational consistency of the overall circuit.

[0038] Optionally, the multiplexing control method further includes:

[0039] Step 205: When the buffer duration exceeds the preset delay threshold, determine the switch type according to the parallel number;

[0040] Step 206: Determine the loss factor in response to the switch type, and retrieve the parallel power according to the parallel number;

[0041] Step 207: Determine the power loss by combining the loss coefficient and the parallel power;

[0042] Step 208: Determine the power factor based on the power loss;

[0043] Step 209: Update the scheduling ratio based on the power coefficient.

[0044] By adopting the above technical solution, the switching types used in different parallel circuits are retrieved, thereby matching the corresponding loss coefficients and calculating the loss power. Then, when the loss power is too high, the scheduling ratio is reduced, achieving precise matching between loss and power scheduling, further optimizing the power allocation logic of multi-channel devices, and improving the precision of junction temperature control.

[0045] Optionally, the multiplexing control method further includes:

[0046] Step 210: When the buffer duration exceeds a preset delay threshold, determine the rate difference based on the rate of change;

[0047] Step 211: Fit a rate change curve in response to the rate difference;

[0048] Step 212: Extract the predicted difference from the rate change curve;

[0049] Step 213: Determine the prediction rate based on the predicted difference and the rate of change;

[0050] Step 214: Update the mutation difference in response to the predicted rate.

[0051] By adopting the above technical solution, the rate difference of the rate of change is calculated and the rate change curve is fitted. The subsequent predicted rate is then predicted according to the trend of the rate change curve, and the junction temperature is controlled according to the predicted rate. This achieves forward-looking regulation of junction temperature changes, avoids junction temperature exceeding the standard due to lagging regulation caused by sudden rate changes, and improves the predictability and timeliness of the control method.

[0052] Optionally, it also includes a sensitivity adjustment method, the sensitivity adjustment method comprising:

[0053] Step 300: When the buffer duration exceeds the preset delay threshold, determine the delay period based on the buffer duration;

[0054] Step 301: Determine the delay density based on the delay period;

[0055] Step 302: If the delay density is greater than a preset density threshold, determine the sensitivity coefficient based on the delay density;

[0056] Step 303: Update the mutation threshold based on the sensitivity coefficient.

[0057] By adopting the above technical solution, for high-frequency delay scenarios caused by excessive buffer time, the delay cycle in which the buffer time exceeds the limit is identified to calculate the delay density of the high-frequency delay scenario. Thus, when the delay density is too large, it is judged that the junction temperature change is relatively drastic. At this time, an appropriate sensitivity coefficient is selected to reduce the sudden change threshold to respond to the junction temperature runaway situation more quickly, avoiding misjudgment or missed judgment under complex operating conditions by fixed threshold, and improving the operating condition adaptability of the control method.

[0058] Optionally, the sensitivity adjustment method further includes:

[0059] Step 304: If the delay density is greater than a preset density threshold, determine the number of delays based on the delay cycle and retrieve the running time;

[0060] Step 305: Determine the runtime based on the runtime;

[0061] Step 306: Calculate the product of the number of delays and the runtime, and define it as the aging degree;

[0062] Step 307: Determine the aging coefficient in response to the stated degree of aging;

[0063] Step 308: Update the sensitivity coefficient based on the aging coefficient.

[0064] By adopting the above technical solution, when the delay density exceeds the standard, the aging degree of the device is quantified by combining the delay cycle and the running time. The sensitivity coefficient is then corrected according to the aging degree, which fully takes into account the impact of SiC device aging characteristics on control accuracy. This achieves full life cycle adaptation of the sensitivity coefficient, avoids threshold adjustment deviation caused by device aging, ensures long-term stability of junction temperature control accuracy, and extends the effective service life of the device.

[0065] Optionally, the sensitivity adjustment method further includes:

[0066] Step 309: If the delay density is greater than the preset density threshold, determine the adjustment range by combining the sensitivity coefficient and the mutation threshold;

[0067] Step 310: Determine the adjustment period based on the adjustment range;

[0068] Step 311: Calculate the quotient of the adjustment amplitude and the adjustment period, and define it as the adjustment step size;

[0069] Step 312: Generate and send a threshold adjustment command by combining the adjustment step size and adjustment period.

[0070] By adopting the above technical solution, the adjustment range of the mutation threshold is determined based on the sensitivity coefficient, thereby calculating the adjustment step size and realizing the step-by-step precise adjustment of the mutation threshold. This avoids control oscillations caused by threshold mutations, ensures that the adjustment process is stable and controllable, and further enhances the stability and reliability of junction temperature control of SiC devices.

[0071] Secondly, this application provides a junction temperature control system based on SiC devices, which adopts the following technical solution:

[0072] A junction temperature control system based on SiC devices, comprising:

[0073] The data acquisition module is used to acquire junction temperature and switching frequency.

[0074] The memory is used to store the program for any of the above-mentioned junction temperature control methods based on SiC devices;

[0075] The processor is the unit of memory that allows programs to be loaded and executed by the processor.

[0076] By adopting the above technical solution, the junction temperature of SiC devices is collected in real time. Based on the junction temperature, an appropriate abrupt change threshold is selected. At the same time, the rate of change is calculated in combination with the switching frequency. When the rate of change exceeds the abrupt change threshold, it is determined that the junction temperature is rising too fast. An appropriate intermediate frequency is determined according to the switching frequency to control the switching frequency to rise gradually. This avoids the junction temperature from fluctuating drastically due to sudden changes in the switching frequency, reduces the impact of junction temperature abrupt changes on the performance of SiC devices, reduces the risk of device damage due to excessive thermal stress, and improves the stability and service life of SiC devices.

[0077] In summary, this application includes at least one of the following beneficial technical effects:

[0078] 1. Real-time acquisition of SiC device junction temperature, selection of appropriate abrupt change threshold based on junction temperature, and calculation of the rate of change in conjunction with switching frequency. When the rate of change exceeds the abrupt change threshold, it is determined that the junction temperature is rising too fast. An appropriate intermediate frequency is determined according to the switching frequency to control the switching frequency to rise gradually, thereby avoiding abrupt changes in switching frequency that cause drastic fluctuations in junction temperature, reducing the impact of junction temperature abrupt changes on SiC device performance, reducing the risk of device damage due to excessive thermal stress, and improving the stability and service life of SiC device operation.

[0079] 2. The gradual increase of the switching frequency requires a certain buffer time, and the greater the rate of change, the longer the buffer time is required. For scenarios where the buffer time exceeds the standard, the degree of exceeding the standard is quantified as a delay error value, so as to accurately match the frequency that needs to be reduced to compensate for the delay error value, thereby ensuring that SiC devices can still maintain the rated operating state under complex working conditions and improving the adaptability of the control method.

[0080] 3. Under the premise that the buffer time exceeds the limit, retrieve the parallel junction temperature and operating threshold of the parallel circuit, thereby quantifying the temperature of the parallel circuit into a junction temperature coefficient, and allocating the increased scheduling power of different parallel circuits to bear the compensation power according to the junction temperature coefficient, thereby realizing the coordinated control of multiple parallel circuits, reducing the performance degradation caused by excessive parallel circuit temperature, and enhancing the operational reliability of the multi-parallel system. Attached Figure Description

[0081] Figure 1 This is a flowchart of a junction temperature control method based on SiC devices;

[0082] Figure 2 This is a flowchart of a multi-channel control method;

[0083] Figure 3 This is a flowchart of the sensitivity adjustment method. Detailed Implementation

[0084] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0085] This application discloses a junction temperature control method based on SiC devices, referring to... Figure 1 A junction temperature control method based on SiC devices includes:

[0086] Step 100: Collect junction temperature.

[0087] Junction temperature refers to the actual operating temperature of the PN junction inside a SiC device chip. It is a core parameter that reflects the thermal stress state of the device and determines whether there is a risk of overheating. Junction temperature can be collected by a temperature sensor built into the SiC device package or indirectly detected by an infrared thermometer. The method of collecting junction temperature is selected by the staff according to the device model, and will not be elaborated here.

[0088] Step 101: Determine the mutation threshold based on the junction temperature and collect the switching frequency.

[0089] The mutation threshold is the critical rate value for determining an abnormal change in the switching frequency. The higher the junction temperature, the lower the mutation threshold (to avoid abrupt frequency changes at high temperatures that could exacerbate overheating). The mutation threshold corresponding to the junction temperature can be found in the threshold correspondence table, which is a data table that records different junction temperatures and their corresponding mutation thresholds.

[0090] Switching frequency refers to the switching frequency at which SiC devices are turned on and off in a circuit. The switching frequency can be acquired by a frequency detector in the circuit. The method of acquiring the switching frequency is selected by the staff according to the actual situation, and will not be elaborated here.

[0091] Step 102: Determine the rate of change based on the switching frequency.

[0092] The rate of change refers to the amount of change in the switching frequency per unit time. It is used to quantify the severity of frequency changes and is the core basis for determining whether a frequency buffer needs to be activated. The rate of change is calculated by dividing the difference in switching frequencies between two adjacent acquisition cycles by the acquisition cycle, where the acquisition cycle refers to the time interval for acquiring switching frequencies.

[0093] Step 103: When the rate of change is greater than the mutation threshold, calculate the difference between the rate of change and the mutation threshold, and define it as the mutation difference value.

[0094] A rate of change greater than the mutation threshold indicates that the frequency is increasing too quickly, which can easily lead to excessively high junction temperatures. The mutation difference is a quantified value of the switching frequency change rate exceeding the mutation threshold, used to accurately match the subsequent buffer duration. If the rate of change is not greater than the mutation threshold, it does not need to be calculated and will not be elaborated here.

[0095] Step 104: Determine the buffer duration based on the mutation difference.

[0096] Buffer duration refers to the transition time set to suppress sudden frequency changes and smoothly adjust the switching frequency. Generally, the number of cycles required for buffering is used as the buffer duration. The larger the sudden change difference, the longer the buffer duration is required to suppress the impact of sudden frequency changes on the junction temperature. The buffer duration corresponding to the sudden change difference can be found from the buffer correspondence table. The buffer correspondence table is a data table that records different sudden change differences and their corresponding buffer durations.

[0097] Step 105: Determine the intermediate frequency by combining the buffer duration and the switching frequency.

[0098] Intermediate frequency refers to the intermediate target value of the switching frequency during the gradual transition within the buffer period. It is used to avoid junction temperature fluctuations caused by direct frequency jumps and to achieve smooth frequency adjustment. That is, the frequency value corresponding to each buffer period when the switching frequency of the previous acquisition cycle gradually changes to the switching frequency of the current cycle within the buffer period. For example, if the buffer period is 3 and the switching frequency changes from 6 to 9, the intermediate frequencies are 7 and 8 respectively. The intermediate frequency is selected by the staff according to the actual situation, which will not be elaborated here.

[0099] Step 106: In response to the intermediate frequency generation, a frequency buffer command is sent.

[0100] The frequency buffer instruction is a control signal that controls the drive circuit to smoothly adjust the switching frequency to the intermediate frequency within the buffer time. The frequency buffer instruction is generated by the controller and sent to the SiC device drive module via the CAN bus. The generation format and transmission protocol are common knowledge in this field and will not be elaborated here.

[0101] The junction temperature of SiC devices is collected in real time. An appropriate abrupt change threshold is selected based on the junction temperature. At the same time, the rate of change is calculated in combination with the switching frequency. When the rate of change exceeds the abrupt change threshold, it is determined that the junction temperature is rising too fast. An appropriate intermediate frequency is determined according to the switching frequency to control the switching frequency to rise gradually. This avoids the junction temperature from fluctuating drastically due to sudden changes in switching frequency, reduces the impact of junction temperature abrupt changes on the performance of SiC devices, reduces the risk of device damage due to excessive thermal stress, and improves the stability and lifespan of SiC devices.

[0102] A junction temperature control method based on SiC devices further includes:

[0103] Step 107: When the buffer duration exceeds the preset delay threshold, determine the delay ratio based on the buffer duration and the preset delay threshold.

[0104] The delay threshold is the critical time value used to determine if the buffer duration is too long and may cause circuit lag. It is preset by the staff according to the circuit response requirements (e.g., 8ms), and will not be elaborated here. A buffer duration greater than the delay threshold means that the time required for frequency smoothing adjustment is too long. The delay ratio refers to the proportion of buffer durations exceeding the delay threshold, used to quantify the degree of delay. It is generally calculated using the formula: Delay ratio = (Buffer duration - Delay threshold) / Delay threshold. It is only calculated when the buffer duration exceeds the delay threshold, and will not be elaborated here.

[0105] Step 108: Determine the delay error value by combining the delay ratio and the mutation difference.

[0106] The delay error value refers to the frequency value that is not fully adjusted even after adjusting the switching frequency at the fastest speed within the delay threshold. Since the change process from the switching frequency of the previous acquisition cycle to the intermediate frequency and then to the switching frequency of the current cycle is a proportional change, it can be calculated using the formula: Delay error value = Delay ratio * Abrupt change difference. The calculation method of the delay error value will not be elaborated here.

[0107] Step 109: Determine the compensation power in response to the delay error value, and determine the circuit number based on the buffer duration.

[0108] Compensation power refers to the power required to reduce the junction temperature to avoid a sudden rise in the junction temperature caused by the increase in the frequency of the delay error. The larger the delay error, the greater the compensation power required. The compensation power corresponding to the delay error can be found in the compensation correspondence table, which is a data table that records different delay error values ​​and their corresponding compensation powers.

[0109] The circuit number is a unique identifier for the circuit containing the currently operating SiC device. It is used to locate the target circuit that needs power compensation. The circuit number can be retrieved from the SiC device. The method for retrieving the circuit number is selected by the staff according to the actual situation, and will not be elaborated here.

[0110] Step 110: Generate and send a power scheduling command based on the circuit number and compensation power.

[0111] Power scheduling commands are control signals that control the power module to adjust the power value of the target circuit. Power scheduling commands are generated by the controller. The generation and transmission methods of power scheduling commands are common knowledge in this field and will not be elaborated here.

[0112] The gradual increase in switching frequency requires a certain buffer time, and the greater the rate of change, the longer the buffer time is required. For scenarios where the buffer time exceeds the standard, the degree of exceeding the standard is quantified as a delay error value, thereby accurately matching the frequency required to reduce the compensation power to compensate for the delay error value. This ensures that SiC devices can still maintain their rated operating state under complex operating conditions and improves the adaptability of the control method.

[0113] A junction temperature control method based on SiC devices further includes:

[0114] Step 111: When the buffer duration exceeds the preset delay threshold, determine the parallel number according to the circuit number.

[0115] Parallel numbering refers to the unique identifier of other SiC device circuits that operate in parallel with the target circuit corresponding to the circuit number. Parallel numbering can be determined through the circuit topology table, which is a table that records the correspondence between parallel circuits corresponding to each main circuit. The method for determining parallel numbering is selected by the staff according to the circuit design scheme, and will not be elaborated here.

[0116] Step 112: Retrieve the parallel junction temperature and working threshold based on the parallel number.

[0117] Parallel junction temperature refers to the junction temperature of the SiC device in the circuit corresponding to the parallel number. The parallel junction temperature can be retrieved from the temperature sensor inside the corresponding SiC device package. The operating threshold refers to the maximum allowable junction temperature threshold of the SiC device in the parallel circuit. The operating threshold corresponding to the parallel number can be found in the device parameter table. The device parameter table is a data table that records different parallel numbers and their corresponding operating thresholds, switching types and loss coefficients.

[0118] Step 113: Determine the junction temperature coefficient by combining the parallel junction temperature and the operating threshold.

[0119] The junction temperature coefficient is a value used to show the temperature of SiC devices in circuits with different parallel numbers. It can be calculated by taking the quotient of the parallel junction temperature and the operating threshold as the junction temperature coefficient. The calculation method of the junction temperature coefficient is selected by the staff according to the actual situation, and will not be elaborated here.

[0120] Step 114: Determine the junction temperature ratio based on the junction temperature coefficient.

[0121] The junction temperature ratio refers to the ratio of the junction temperature coefficient of each parallel circuit to the sum of the junction temperature coefficients of all parallel circuits. The calculation method for the junction temperature ratio is selected by the staff according to the actual situation, and will not be elaborated here.

[0122] Step 115: Determine the scheduling ratio in response to the junction temperature ratio.

[0123] The scheduling ratio refers to the proportion of compensation power allocated to each parallel circuit. The larger the junction temperature ratio, the worse the temperature condition of the corresponding parallel circuit, and the smaller the compensation power that the corresponding parallel circuit can bear. A smaller scheduling ratio is adopted. The scheduling ratio corresponding to the junction temperature ratio can be found in the scheduling correspondence table. The scheduling correspondence table is a data table that records different junction temperature ratios and their corresponding scheduling ratios.

[0124] Step 116: Calculate the product of the scheduling ratio and the compensation power, and define it as the scheduling power.

[0125] Dispatch power refers to the specific compensation power value allocated to each parallel circuit, ensuring that each parallel circuit undertakes the appropriate power according to its own thermal load status.

[0126] Step 117: In response to the parallel numbering and scheduling power update power scheduling instruction.

[0127] After allocating the dispatched power to the parallel circuits with parallel numbers according to the power dispatch instructions, the intermediate frequency is updated according to the delay threshold and the switching frequency, and the switching frequency is adjusted in a timely manner.

[0128] Under the premise that the buffer time exceeds the limit, the parallel junction temperature and operating threshold of the parallel circuit are retrieved, thereby quantifying the temperature of the parallel circuit into a junction temperature coefficient. The additional scheduling power of the compensation power undertaken by different parallel circuits is allocated according to the junction temperature coefficient, thereby realizing the coordinated control of multiple parallel circuits, reducing the performance degradation caused by excessively high parallel circuit temperature, and enhancing the operational reliability of the multi-parallel system.

[0129] Reference Figure 2 Multiplexing control methods include:

[0130] Step 200: When the buffer duration is greater than the preset delay threshold, determine the junction temperature difference by combining the junction temperature and the parallel junction temperature.

[0131] Junction temperature difference refers to the difference between the junction temperature of the target circuit corresponding to the circuit number and the junction temperature of each parallel circuit. It is used to judge the junction temperature uniformity of multiple circuits. The calculation method of junction temperature difference is selected by the staff according to the actual situation, and will not be elaborated here.

[0132] Step 201: Determine the average temperature difference based on the junction temperature difference.

[0133] The average temperature difference refers to the arithmetic mean of all junction temperature differences. It is used to reflect the overall balance level of junction temperature in multiple circuits. The calculation method for the average temperature difference is selected by the staff according to the actual situation, and will not be elaborated here.

[0134] Step 202: Calculate the difference between the junction temperature difference and the mean temperature difference, and define it as the fluctuation difference value.

[0135] Fluctuation difference refers to the quantitative value of the deviation of the junction temperature difference of a single circuit from the average temperature difference. It is used to determine whether there is abnormal fluctuation in the junction temperature of a parallel circuit. The larger the fluctuation difference, the more obvious the abnormality.

[0136] Step 203: When the fluctuation difference does not fall within the preset fluctuation range, determine the fluctuation coefficient based on the fluctuation difference.

[0137] The fluctuation threshold is the critical value for determining abnormal junction temperature fluctuations, preset to 2℃ (adjustable according to circuit stability requirements). The fluctuation threshold is selected by the staff based on the actual situation and will not be elaborated here. The fluctuation coefficient is the correction value used to adjust the scheduling ratio according to the degree of fluctuation abnormality. The larger the fluctuation difference, the higher the junction temperature of the corresponding parallel circuit. It is necessary to prevent the junction temperature of the parallel circuit from rising further, i.e., reduce the scheduling ratio and use a larger fluctuation coefficient. The fluctuation coefficient corresponding to the fluctuation difference can be found in the fluctuation correspondence table. The difference between the original scheduling ratio and the fluctuation coefficient can be calculated as the new scheduling ratio. After the scheduling ratio of the corresponding parallel circuit is reduced according to the fluctuation coefficient, the fluctuation coefficient is evenly distributed to the scheduling ratios of other parallel circuits.

[0138] Step 204: Update the scheduling ratio based on the fluctuation coefficient.

[0139] In multi-channel control scenarios, the average temperature difference of parallel circuits is calculated by combining junction temperature and parallel junction temperature, thereby identifying parallel circuits with excessively high or low junction temperatures. The scheduling ratio is then adjusted according to the junction temperature deviation to ensure that the junction temperatures of multiple devices are similar, thus improving the overall thermal stability and operational consistency of the circuit.

[0140] Multiplexing methods also include:

[0141] Step 205: When the buffer duration exceeds the preset delay threshold, determine the switch type according to the parallel number.

[0142] The switch type refers to the switching operation mode of the SiC device in the circuit corresponding to the parallel number, i.e., soft switching or hard switching. The switch type can be retrieved from the SiC device. The method of retrieving the switch type is selected by the staff according to the actual situation, and will not be elaborated here.

[0143] Step 206: Determine the loss factor in response to the switch type, and retrieve the parallel power according to the parallel number.

[0144] The loss factor refers to the proportion of energy loss generated during the dynamic switching process of SiC devices when they are switched on and off. The loss factor corresponding to the parallel number and switch type can be found in the device parameter table.

[0145] Parallel power refers to the current actual operating power of the parallel circuit. Parallel power can be retrieved from the power acquisition system. The method for retrieving parallel power is selected by the staff according to the actual situation, and will not be elaborated here.

[0146] Step 207: Determine the power loss by combining the loss coefficient and the parallel power.

[0147] Power loss refers to the power loss value of SiC devices in parallel circuits due to switching losses. The power loss can be calculated by multiplying the loss coefficient and the parallel power. The calculation method for power loss is selected by the staff according to the actual situation and will not be elaborated here.

[0148] Step 208: Determine the power factor based on the power loss.

[0149] The power factor is a correction value used to adjust the scheduling ratio according to the power loss. The greater the power loss, the faster the junction temperature rises. Therefore, a larger power factor is used to suppress the junction temperature rise. The power factor corresponding to the power loss can be found in the power correspondence table. The power correspondence table is a data table that records different power losses and their corresponding power factors. The difference between the original scheduling ratio and the power factor can be calculated as the new scheduling ratio, and the power factor is evenly distributed to the scheduling ratios of other parallel circuits.

[0150] Step 209: Update the scheduling ratio based on the power coefficient.

[0151] By retrieving the switching types used in different parallel circuits, the corresponding loss coefficients are matched and the loss power is calculated. Then, when the loss power is too high, the scheduling ratio is reduced to achieve precise matching between loss and power scheduling. This further optimizes the power allocation logic of multi-channel devices and improves the precision of junction temperature control.

[0152] Multiplexing methods also include:

[0153] Step 210: When the buffer duration exceeds the preset delay threshold, determine the rate difference based on the rate of change.

[0154] Rate difference refers to the magnitude of change in rate of change, which is calculated as the difference in the rate of change between adjacent acquisition cycles. The calculation method for rate difference is selected by the staff according to the actual situation and will not be elaborated here.

[0155] Step 211: Fit a rate change curve in response to the rate difference.

[0156] A rate change curve is a line graph with time as the horizontal axis and rate difference as the vertical axis, reflecting the trend of the rate of change over time. The rate change curve is generated by fitting using the linear least squares method. The fitting method for the rate change curve is common knowledge in this field and will not be elaborated here.

[0157] Step 212: Extract the predicted difference from the rate change curve.

[0158] The prediction difference refers to the rate difference predicted for the next acquisition cycle based on the rate change curve. The method for extracting the prediction difference is common knowledge to those in the field and will not be elaborated here.

[0159] Step 213: Determine the prediction rate based on the predicted difference and the rate of change.

[0160] The prediction rate refers to the rate of change of the switching frequency in the next acquisition cycle. It can be calculated as the sum of the current rate of change and the prediction difference. The calculation method of the prediction rate is selected by the staff according to the actual situation, and will not be elaborated here.

[0161] Step 214: Update the mutation difference in response to the predicted rate.

[0162] The rate difference of the rate of change is calculated and the rate change curve is fitted. The subsequent predicted rate is then predicted according to the trend of the rate change curve. The junction temperature is then controlled according to the predicted rate to achieve forward-looking regulation of junction temperature changes. This avoids junction temperature exceeding the limit due to lagging regulation caused by sudden rate changes, and improves the predictability and timeliness of the control method.

[0163] Reference Figure 3 Sensitivity adjustment methods include:

[0164] Step 300: When the buffer duration is greater than the preset delay threshold, the delay period is determined according to the buffer duration.

[0165] The delay period refers to the acquisition period value when the buffer time exceeds the delay threshold. It is used to show the frequency of delays. The delay period can be retrieved from the junction temperature control system based on SiC devices. The method for determining the delay period is selected by the staff according to the actual situation, and will not be elaborated here.

[0166] Step 301: Determine the delay density based on the delay period.

[0167] Delay density refers to the frequency of delay cycles occurring per unit of time. It can be calculated by counting the number of delay cycles in the last ten collection cycles of the current collection cycle. The method for determining delay density is selected by the staff based on the actual situation and will not be elaborated here.

[0168] Step 302: If the delay density is greater than a preset density threshold, determine the sensitivity coefficient based on the delay density.

[0169] The density threshold refers to the critical frequency at which a circuit is determined to be in a high-frequency delay state. The density threshold is selected by the operator based on the actual situation and will not be elaborated upon here. A delay density greater than the density threshold indicates a more drastic change in junction temperature. The sensitivity coefficient is a correction value used to adjust the abrupt change threshold, lowering the threshold and improving control sensitivity. The higher the delay density, the lower the sensitivity coefficient. The sensitivity coefficient corresponding to the delay density can be found in the sensitivity correspondence table, which records different delay densities and their corresponding sensitivity coefficients. Generally, the product of the original abrupt change threshold and the sensitivity coefficient is calculated as the new abrupt change threshold.

[0170] Step 303: Update the mutation threshold based on the sensitivity coefficient.

[0171] For high-frequency delay scenarios caused by excessive buffer duration, the delay cycle in which the buffer duration exceeds the limit is identified to calculate the delay density of the high-frequency delay scenario. When the delay density is too large, it is judged that the junction temperature change is relatively drastic. At this time, an appropriate sensitivity coefficient is selected to reduce the abrupt change threshold to respond more quickly to the junction temperature runaway situation, avoiding misjudgment or omission under complex operating conditions with a fixed threshold, and improving the operating condition adaptability of the control method.

[0172] Sensitivity adjustment methods also include:

[0173] Step 304: If the delay density is greater than the preset density threshold, determine the number of delays based on the delay cycle and retrieve the running time.

[0174] The number of delays refers to the total number of delay cycles that the corresponding SiC device has been operating to date. The method for determining the number of delays is selected by the staff based on the actual situation, and will not be elaborated here.

[0175] The running time refers to the time when the corresponding SiC device starts running. The running time corresponding to the circuit number can be found in the running correspondence table. The running correspondence table is a data table that records different circuit numbers and their corresponding running times. Whenever the SiC device is replaced, the corresponding time is recorded in the running correspondence table and the corresponding delay period is cleared.

[0176] Step 305: Determine the runtime based on the runtime time.

[0177] Runtime refers to the cumulative working time of a SiC device from startup to the current moment. The calculation method for runtime is selected by the staff based on the actual situation and will not be elaborated here.

[0178] Step 306: Calculate the product of the number of delays and the runtime, and define it as the aging degree.

[0179] The degree of aging refers to a parameter that quantifies the aging state of SiC devices and is used to reflect the impact of aging on junction temperature. The greater the number of delays, the more likely the junction temperature of the SiC device will run away from control. The greater the damage of high temperature to SiC devices, the more severe the aging and the greater the degree of aging.

[0180] Step 307: Determine the aging factor in response to the aging degree.

[0181] The aging factor refers to the correction value of the sensitivity factor, which is used to increase the mutation threshold and reduce the control sensitivity. The greater the aging degree, the easier it is for the junction temperature of the SiC device to rise, so a larger aging factor is used. The aging factor corresponding to the aging degree can be found in the aging correspondence table. The aging correspondence table is a data table that records different aging degrees and their corresponding aging factors. Generally, the product of the original sensitivity factor and the aging factor is calculated as the new sensitivity factor.

[0182] Step 308: Update the sensitivity coefficient based on the aging coefficient.

[0183] When the delay density exceeds the limit, the aging degree of the device is quantified by combining the delay cycle and the running time. The sensitivity coefficient is then corrected according to the aging degree, which fully takes into account the impact of SiC device aging characteristics on control accuracy. This achieves full life cycle adaptation of the sensitivity coefficient, avoids threshold adjustment deviation due to device aging, ensures long-term stability of junction temperature control accuracy, and extends the effective service life of the device.

[0184] Sensitivity adjustment methods also include:

[0185] Step 309: If the delay density is greater than the preset density threshold, determine the adjustment range by combining the sensitivity coefficient and the mutation threshold.

[0186] The adjustment amplitude refers to the amount of adjustment made to the sudden change threshold in a single operation. It is used to avoid control oscillations caused by sudden changes in the threshold and to ensure a smooth adjustment process. It can be calculated using the formula: Adjustment amplitude = Original sudden change threshold - Original sudden change threshold * Sensitivity coefficient.

[0187] Step 310: Determine the adjustment period based on the adjustment range.

[0188] The adjustment period refers to the time interval required to complete one change threshold adjustment. Generally, the required number of acquisition cycles is used as the adjustment period. The larger the adjustment range, the larger the adjustment period, to ensure that the threshold adjustment is adapted to the circuit response and to avoid fluctuations caused by excessively fast adjustment. The adjustment period corresponding to the adjustment range can be found from the period correspondence table, which is a data table that records different adjustment ranges and their corresponding adjustment periods.

[0189] Step 311: Calculate the quotient of the adjustment amplitude and the adjustment period, and define it as the adjustment step size.

[0190] The adjustment step size refers to the reduction in the amount of change in the mutation threshold each time within the adjustment period. This is used to achieve a step-by-step, smooth adjustment of the mutation threshold and avoid control imbalance caused by a one-time adjustment.

[0191] Step 312: Generate and send a threshold adjustment command by combining the adjustment step size and adjustment period.

[0192] Threshold adjustment command refers to the control signal of the controller to adjust the sudden change threshold in a step-by-step manner. The threshold adjustment command is generated by the main controller and sent to the local controller for execution. The generation and transmission methods are common knowledge in this field.

[0193] The adjustment range of the mutation threshold is determined by the sensitivity coefficient, and the adjustment step size is calculated to achieve precise step adjustment of the mutation threshold. This avoids control oscillations caused by threshold mutations, ensures a smooth and controllable adjustment process, and further enhances the stability and reliability of junction temperature control of SiC devices.

[0194] Based on the same inventive concept, embodiments of the present invention provide a junction temperature control system based on SiC devices, comprising:

[0195] The data acquisition module is used to acquire junction temperature and switching frequency.

[0196] The memory is used to store the program for any of the above-mentioned junction temperature control methods based on SiC devices;

[0197] The processor is the unit of memory that allows programs to be loaded and executed by the processor.

[0198] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional modules is used as an example. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. The specific working process of the system, device, and unit described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0199] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A junction temperature control method based on SiC devices, characterized in that, include: Step 100: Collect junction temperature; Step 101: Determine the sudden change threshold based on the junction temperature and collect the switching frequency; Step 102: Determine the rate of change based on the switching frequency; Step 103: When the rate of change is greater than the mutation threshold, calculate the difference between the rate of change and the mutation threshold, and define it as the mutation difference value; Step 104: Determine the buffer duration based on the mutation difference; Step 105: Determine the intermediate frequency by combining the buffer duration and the switching frequency; Step 106: In response to the intermediate frequency generation, a frequency buffer command is sent.

2. The junction temperature control method based on SiC devices according to claim 1, characterized in that, Also includes: Step 107: When the buffer duration exceeds the preset delay threshold, determine the delay ratio based on the buffer duration and the preset delay threshold; Step 108: Determine the delay error value by combining the delay ratio and the mutation difference; Step 109: Determine the compensation power in response to the delay error value, and determine the circuit number based on the buffer duration; Step 110: Generate and send a power scheduling command based on the circuit number and compensation power.

3. The junction temperature control method based on SiC devices according to claim 2, characterized in that, Also includes: Step 111: When the buffer duration exceeds the preset delay threshold, determine the parallel numbering based on the circuit number; Step 112: Retrieve the parallel connection temperature and operating threshold based on the parallel number; Step 113: Determine the junction temperature coefficient by combining the parallel junction temperature and the operating threshold; Step 114: Determine the junction temperature ratio based on the junction temperature coefficient; Step 115: Determine the scheduling ratio in response to the junction temperature ratio; Step 116: Calculate the product of the scheduling ratio and the compensation power, and define it as the scheduling power; Step 117: In response to the parallel numbering and scheduling power update power scheduling instruction.

4. The junction temperature control method based on SiC devices according to claim 3, characterized in that, It also includes a multiplexing control method, which includes: Step 200: When the buffer duration exceeds the preset delay threshold, determine the junction temperature difference by combining the junction temperature and the parallel junction temperature; Step 201: Determine the average temperature difference based on the junction temperature difference; Step 202: Calculate the difference between the junction temperature difference and the mean temperature difference, and define it as the fluctuation difference value; Step 203: When the fluctuation difference does not fall within the preset fluctuation range, determine the fluctuation coefficient based on the fluctuation difference; Step 204: Update the scheduling ratio based on the fluctuation coefficient.

5. The junction temperature control method based on SiC devices according to claim 4, characterized in that, The multiplexing control method further includes: Step 205: When the buffer duration exceeds the preset delay threshold, determine the switch type according to the parallel number; Step 206: Determine the loss factor in response to the switch type, and retrieve the parallel power according to the parallel number; Step 207: Determine the power loss by combining the loss coefficient and the parallel power; Step 208: Determine the power factor based on the power loss; Step 209: Update the scheduling ratio based on the power coefficient.

6. The junction temperature control method based on SiC devices according to claim 5, characterized in that, The multiplexing control method further includes: Step 210: When the buffer duration exceeds a preset delay threshold, determine the rate difference based on the rate of change; Step 211: Fit a rate change curve in response to the rate difference; Step 212: Extract the predicted difference from the rate change curve; Step 213: Determine the prediction rate based on the predicted difference and the rate of change; Step 214: Update the mutation difference in response to the predicted rate.

7. The junction temperature control method based on SiC devices according to claim 6, characterized in that, It also includes a sensitivity adjustment method, the sensitivity adjustment method comprising: Step 300: When the buffer duration exceeds the preset delay threshold, determine the delay period based on the buffer duration; Step 301: Determine the delay density based on the delay period; Step 302: If the delay density is greater than a preset density threshold, determine the sensitivity coefficient based on the delay density; Step 303: Update the mutation threshold based on the sensitivity coefficient.

8. The junction temperature control method based on SiC devices according to claim 7, characterized in that, The sensitivity adjustment method further includes: Step 304: If the delay density is greater than a preset density threshold, determine the number of delays based on the delay cycle and retrieve the running time; Step 305: Determine the runtime based on the runtime; Step 306: Calculate the product of the number of delays and the runtime, and define it as the aging degree; Step 307: Determine the aging coefficient in response to the stated degree of aging; Step 308: Update the sensitivity coefficient based on the aging coefficient.

9. The junction temperature control method based on SiC devices according to claim 8, characterized in that, The sensitivity adjustment method further includes: Step 309: If the delay density is greater than the preset density threshold, determine the adjustment range by combining the sensitivity coefficient and the mutation threshold; Step 310: Determine the adjustment period based on the adjustment range; Step 311: Calculate the quotient of the adjustment amplitude and the adjustment period, and define it as the adjustment step size; Step 312: Generate and send a threshold adjustment command by combining the adjustment step size and adjustment period.

10. A junction temperature control system based on SiC devices, characterized in that, include: The data acquisition module is used to acquire junction temperature and switching frequency. A memory for storing a program for a junction temperature control method based on a SiC device as described in any one of claims 1 to 9; The processor is the unit of memory that allows programs to be loaded and executed by the processor.

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