A magnetic suspension frequency converter IGBT temperature control method, device and storage medium

Abstract

The application discloses a kind of magnetic suspension frequency converter IGBT temperature control method, device, magnetic suspension frequency converter control system, storage medium and computer program product, the method includes: with reference sampling frequency acquisition IGBT module's temperature data;According to temperature data determines temperature variation rate, according to temperature variation rate adjusts the temperature sampling frequency of IGBT module;With the sampling frequency of adjustment acquisition IGBT module's real-time temperature;Real-time temperature is compared with multiple levels preset temperature threshold, and according to the comparison result, the temperature protection operation of corresponding grade is executed.The scheme, improves the temperature control response accuracy under dynamic condition, improves system operation energy efficiency.

Description

Technical Field

[0001] This invention belongs to the field of magnetic levitation frequency converter control technology, specifically relating to a magnetic levitation frequency converter IGBT temperature control method, device, magnetic levitation frequency converter control system, storage medium, and computer program product. Background Technology

[0002] Inverters are the core equipment for power conversion and motor drive. IGBT modules, as the core power switching devices of inverters, directly determine the operational reliability and service life of inverters through their junction temperature. Magnetic levitation systems experience frequent load fluctuations and a wide dynamic range of operating conditions. IGBT switching losses change in real time with the load, resulting in highly dynamic junction temperature characteristics. This places extremely high demands on the real-time performance, accuracy, and long-term reliability of temperature control.

[0003] For temperature control of IGBT modules, a static control scheme based on casing temperature sampling is commonly used. This involves collecting temperature data at fixed intervals using a temperature sensor installed on the module casing, and triggering thermal adjustment, frequency reduction, or shutdown protection based on a preset fixed temperature threshold. This scheme is simple in architecture, easy to implement, and can meet basic overheat protection requirements under steady-state conditions.

[0004] However, the aforementioned existing technologies are essentially passive control modes with fixed sampling periods and static protection thresholds, which cannot adapt to the dual characteristics of dynamic operating conditions and device performance degradation of magnetic levitation frequency converters. This is also a major problem that has long existed in this field: existing temperature control solutions are difficult to simultaneously meet the coordinated requirements of temperature control response accuracy, system operating energy efficiency, and long-term operating reliability under dynamic operating conditions throughout the entire service life of IGBTs.

[0005] Specifically, this problem manifests in several dimensions: First, the fixed sampling period and indirect temperature measurement method using the casing cannot accurately capture rapid temperature rises under transient loads, resulting in significant temperature lag and a high risk of junction temperature overshoot exceeding safe limits, leading to thermal damage to the device. Using high-frequency sampling throughout to improve response speed would significantly increase the controller's computing power, making it counterproductive. Second, a fixed protection threshold cannot match the changes in thermal resistance caused by fouling, flow rate decay, and thermal fatigue aging of the IGBT device. This may lead to protection failure when heat dissipation capacity decreases, or sudden failures due to insufficient safety margins at the end of the device's lifespan, failing to adapt to performance changes throughout the device's lifecycle. Third, static threshold control struggles to balance light-load energy efficiency with heavy-load reliability. Redundant operation of the heat dissipation system under light load conditions results in energy waste, while the lack of a progressive protection mechanism under heavy load conditions leads to either overly aggressive or insufficient protection actions, failing to achieve synergistic optimization of temperature control performance and system energy efficiency.

[0006] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0007] The purpose of this invention is to provide a method, device, control system, storage medium, and computer program product for temperature control of IGBTs in magnetic levitation frequency converters. This addresses the problem that passive temperature control schemes using fixed sampling periods and static thresholds in related solutions cannot adapt to dynamic operating condition fluctuations and device aging and degradation, and are difficult to simultaneously achieve high temperature control response accuracy, system operating efficiency, and full life-cycle operational reliability. The invention improves temperature control response accuracy under dynamic operating conditions, enhances system operating efficiency, and achieves a synergistic optimization effect on the operational safety and continuity of IGBTs in magnetic levitation frequency converters.

[0008] This invention provides a temperature control method for IGBTs in a magnetic levitation frequency converter, comprising: acquiring temperature data of the IGBT module at a reference sampling frequency; determining the temperature change rate based on the temperature data; adjusting the temperature sampling frequency of the IGBT module according to the temperature change rate; acquiring the real-time temperature of the IGBT module at the adjusted sampling frequency; comparing the real-time temperature with multiple preset temperature thresholds; and performing corresponding level temperature protection operations based on the comparison results.

[0009] In some implementations, adjusting the temperature sampling frequency of the IGBT module according to the temperature change rate includes: comparing the temperature change rate with a preset rate threshold; increasing the temperature sampling frequency when the temperature change rate is greater than the preset rate threshold; and maintaining a reference temperature sampling frequency when the temperature change rate is not greater than the preset rate threshold.

[0010] In some embodiments, the multi-level preset temperature thresholds include a first preset temperature threshold, a second preset temperature threshold, and a third preset temperature threshold, which are progressively increased. The real-time temperature is compared with the multi-level preset temperature thresholds, and temperature protection operations of the corresponding level are performed according to the comparison results, including: reducing the output operating frequency of the magnetic levitation inverter when the real-time temperature exceeds the first preset temperature threshold; reducing the output load power of the magnetic levitation inverter when the real-time temperature exceeds the second preset temperature threshold; and triggering the shutdown protection of the magnetic levitation inverter when the real-time temperature exceeds the third preset temperature threshold.

[0011] In some implementations, when the real-time temperature exceeds a second preset temperature threshold, the operating power of the magnetic levitation inverter's heat dissipation system is increased.

[0012] In some embodiments, the method further includes: collecting electrical operating parameters of the magnetic levitation frequency converter, calculating the instantaneous loss of the IGBT in conjunction with a preset IGBT switching characteristic model; identifying the equivalent thermal impedance of the IGBT module online based on the instantaneous loss and the real-time temperature; comparing the equivalent thermal impedance with a preset thermal impedance reference value; and when the deviation between the equivalent thermal impedance and the preset thermal impedance reference value reaches a preset deviation threshold, dynamically correcting the judgment threshold for the rate of temperature change and / or multiple preset temperature thresholds according to the ratio of the equivalent thermal impedance to the preset thermal impedance reference value.

[0013] In some embodiments, the method further includes: periodically calculating the temperature cycle amplitude and temperature dwell time of the IGBT, and cumulatively calculating the thermal fatigue damage of the IGBT; obtaining the remaining service life of the IGBT based on the thermal fatigue damage; comparing the remaining service life with a multi-level preset service life threshold to determine the service life range in which the remaining service life is located; adjusting the values ​​of the multi-level preset temperature thresholds according to the corresponding service life range, and correspondingly limiting the maximum operating power of the magnetic levitation frequency converter.

[0014] In conjunction with the above method, another aspect of the present invention provides a magnetic levitation inverter IGBT temperature control device, comprising: a data acquisition unit configured to acquire temperature data of the IGBT module at a reference sampling frequency; the data acquisition unit further configured to determine a temperature change rate based on the temperature data and adjust the temperature sampling frequency of the IGBT module according to the temperature change rate; the data acquisition unit further configured to acquire the real-time temperature of the IGBT module at the adjusted sampling frequency; and a protection unit configured to compare the real-time temperature with multiple preset temperature thresholds and perform corresponding level temperature protection operations based on the comparison results.

[0015] In conjunction with the above-mentioned device, the present invention further provides a magnetic levitation frequency converter control system, including: the magnetic levitation frequency converter IGBT temperature control device described above.

[0016] In conjunction with the above method, the present invention further provides a storage medium comprising a stored program, wherein, when the program is executed, the device containing the storage medium is controlled to perform the above-described magnetic levitation inverter IGBT temperature control method.

[0017] In conjunction with the above method, the present invention further provides a computer program product comprising a computer program that, when processed and executed, implements the steps of the above-described magnetic levitation inverter IGBT temperature control method.

[0018] The present invention acquires temperature data of the IGBT module at a reference sampling frequency, adaptively adjusts the temperature sampling frequency according to the rate of temperature change, and then acquires the real-time temperature of the IGBT at the adjusted sampling frequency. By comparing the real-time temperature with multiple preset temperature thresholds, the corresponding level of temperature protection operation is executed, which effectively improves the temperature control response accuracy under dynamic operating conditions, improves the system operating efficiency, and realizes the synergistic optimization of IGBT operating safety and magnetic levitation inverter operating continuity.

[0019] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention.

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating an embodiment of the IGBT temperature control method for magnetic levitation frequency converters of the present invention.

[0022] Figure 2 This is a schematic diagram of an embodiment of the magnetic levitation inverter IGBT temperature control device of the present invention;

[0023] Figure 3 This is a schematic diagram of the magnetic levitation frequency conversion system.

[0024] Figure 4 This is a flowchart illustrating another embodiment of the IGBT temperature control method for a magnetic levitation frequency converter.

[0025] Referring to the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0026] 101 - Acquisition unit; 102 - Protection unit. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0028] According to an embodiment of the present invention, a method for temperature control of IGBT in a magnetic levitation frequency converter is provided, wherein the structure of the magnetic levitation frequency converter system is as follows: Figure 3As shown, the rectifier side consists of a three-phase AC input power supply and a fully controlled rectifier circuit (including IGBT switches), efficiently rectifying the 50Hz / 60Hz AC power into stable DC power. The inverter side consists of a fully controlled inverter circuit (including IGBT switches) and a load (such as a motor), inverting the DC power into AC power with variable frequency / amplitude to drive the load. The system is configured with 12 IGBT modules (2 per phase, redundant design), operating at a high-frequency switching frequency of 5-20kHz. High-frequency switching operation causes significant heat loss in the IGBT modules (typically 100-300W / module). If the cooling system cannot dissipate the heat in time, the module junction temperature will rise rapidly. When the junction temperature exceeds the safe threshold (usually 125℃), it will cause thermal runaway, short circuit, or permanent device damage, resulting in system downtime, equipment scrapping, and repair costs of up to tens of thousands of yuan. Therefore, dynamic and precise control of the IGBT temperature is required.

[0029] like Figure 1 The flowchart shown is a schematic diagram of an embodiment of the method of the present invention. The magnetic levitation frequency converter IGBT temperature control method may include steps S110 to S140.

[0030] In step S110, temperature data of the IGBT module is acquired at a reference sampling frequency.

[0031] The reference sampling frequency is the periodic frequency at which temperature data is collected under the system's default state, such as 10 seconds, suitable for steady-state, low-temperature rise rate normal operating conditions. Under normal operating conditions with stable load and gradual temperature rise, the thermal state of the IGBT module changes slowly, and a lower sampling frequency can meet the basic requirements of temperature monitoring. Using a reference sampling frequency can reduce the sampling operation overhead of the controller, reduce the continuous power consumption of the sampling circuit, and balance basic monitoring capabilities with system operating energy efficiency. Specifically, when the system powers on and enters normal operating state, it periodically collects temperature data from the IGBT module according to the preset reference sampling period to obtain continuous temperature time-series values.

[0032] A high-precision NTC thermistor sensor can be precisely integrated on the surface of each IGBT module chip (close to the chip junction area). The sensor is connected to the microcontroller through a low-noise signal conditioning circuit and acquires temperature data with a 10-second reference cycle.

[0033] In step S120, the temperature change rate is determined based on the temperature data, and the temperature sampling frequency of the IGBT module is adjusted based on the temperature change rate.

[0034] The rate of temperature change is the amount of temperature change in an IGBT module per unit time. It characterizes how quickly the IGBT temperature rises or falls, reflecting the severity of changes in heat load. A faster rate of temperature rise indicates more drastic load fluctuations and a faster increase in heat load, thus increasing the risk of temperature overshoot. Traditional fixed-frequency sampling schemes either waste computing power by using high-frequency sampling throughout or fail to capture transient temperature rises by using low-frequency sampling throughout. By adjusting the sampling frequency in conjunction with the rate of temperature change, low-frequency sampling can be maintained during periods of gradual temperature rise to save energy and computing power, while the sampling frequency can be automatically increased during periods of rapid temperature rise to improve real-time monitoring, achieving adaptive matching between the sampling strategy and operating conditions.

[0035] Specifically, the system performs interpolation on multiple sets of continuously acquired temperature data to calculate the temperature change per unit time, thus obtaining the rate of temperature change. For example, the formula for calculating the rate of temperature change is ΔT / Δt=(T n -T n-10 ) / 10, where T n T represents the current temperature. n-10 The temperature value is from 10 seconds ago. The rate of temperature change is then used as a criterion to adjust the temperature sampling period and frequency accordingly.

[0036] In some implementations, step S120, adjusting the temperature sampling frequency of the IGBT module according to the temperature change rate, includes: comparing the temperature change rate with a preset rate threshold; increasing the temperature sampling frequency when the temperature change rate is greater than the preset rate threshold; and maintaining the reference temperature sampling frequency when the temperature change rate is not greater than the preset rate threshold.

[0037] A preset rate threshold (e.g., 0.3℃ / s) is used to determine whether the current IGBT temperature rise is too rapid and whether there is a risk of transient overheating. Specifically, after calculating the current temperature change rate, the system compares this value with the pre-stored preset rate threshold. If the comparison result shows that the current temperature change rate is higher than the preset rate threshold, the system adjusts the temperature acquisition timer configuration, shortens the sampling period, and increases the number of temperature acquisitions per unit time (e.g., the frequency is increased to 1 second / time). If the comparison result shows that the current temperature change rate does not exceed the preset rate threshold, the system maintains the original baseline sampling period and continues to acquire temperature data at the default frequency.

[0038] Optionally, multiple preset rate thresholds can be set in progressively increasing increments, corresponding to different sampling frequencies, enabling smooth adjustment of the sampling frequency across multiple levels. The average temperature change rate after a sliding window can be used for threshold comparison to filter out random fluctuations in temperature sampling and avoid erroneous triggering of sampling frequency switching.

[0039] By adjusting the temperature sampling frequency, a low-power, low-computing-overhead sampling configuration can be maintained when the IGBT temperature rises slowly, and the sampling density can be automatically increased when the temperature rises too quickly to enhance the temperature control response capability. This solves both the resource waste problem caused by traditional fixed high-frequency sampling and the temperature control response lag problem caused by fixed low-frequency sampling. Without increasing hardware costs, it simultaneously takes into account the system's energy efficiency and the real-time performance of temperature monitoring.

[0040] In step S130, the real-time temperature of the IGBT module is acquired at the adjusted sampling frequency.

[0041] The accuracy and timeliness of temperature protection actions highly depend on the real-time nature of the temperature acquisition data. When the sampling frequency is matched with the current temperature rise conditions, the acquired real-time temperature can more accurately reflect the true thermal state of the IGBT, avoiding problems such as missed temperature peaks and delayed judgments due to excessively long sampling intervals. Specifically, the system continuously acquires the current temperature value of the IGBT module according to the adjusted sampling period.

[0042] In step S140, the real-time temperature is compared with multiple preset temperature thresholds, and the corresponding level of temperature protection operation is executed according to the comparison result.

[0043] The thermal risk of IGBT modules increases gradually with rising temperature, and the risk of device damage and temperature control requirements differ across different temperature ranges. Protection schemes with a single temperature threshold can only trigger a single action, either causing excessive intervention in low-risk stages that impacts equipment operation, or insufficient intervention in high-risk stages that leads to device damage. Adopting a multi-level threshold approach with corresponding multi-level protection enables progressive temperature intervention: mild intervention at lower temperatures to ensure continuous equipment operation, and severe intervention at higher temperatures to ensure device safety, thus balancing operational reliability and equipment efficiency.

[0044] Specifically, the system compares the collected real-time temperature values ​​with a series of pre-set, progressively increasing temperature thresholds to determine the temperature range in which the real-time temperature falls; based on the thermal risk level corresponding to the temperature range, it outputs the corresponding temperature control protection command and executes the appropriate intervention action.

[0045] In some embodiments, the multi-level preset temperature thresholds include a first preset temperature threshold, a second preset temperature threshold, and a third preset temperature threshold, which increase progressively. In step S140, the real-time temperature is compared with the multi-level preset temperature thresholds, and temperature protection operations of the corresponding level are performed based on the comparison results, including: reducing the output operating frequency of the magnetic levitation inverter when the real-time temperature exceeds the first preset temperature threshold; reducing the output load power of the magnetic levitation inverter when the real-time temperature exceeds the second preset temperature threshold; and triggering the shutdown protection of the magnetic levitation inverter when the real-time temperature exceeds the third preset temperature threshold.

[0046] Specifically, when the system determines that the real-time temperature is higher than the first preset temperature threshold but lower than the second preset temperature threshold, the controller sends a frequency adjustment command to the inverter drive module, reducing the inverter's output operating frequency by a preset ratio. When the system determines that the real-time temperature is higher than the second preset temperature threshold but lower than the third preset temperature threshold, the controller sends a power adjustment command to the load control module, reducing the inverter's output load power by a preset ratio. When the system determines that the real-time temperature is higher than the third preset temperature threshold, the controller immediately outputs a fault shutdown command, cutting off the gate drive power of all IGBT modules, stopping power output, and putting the inverter into a safe shutdown state.

[0047] Choosing frequency reduction as the first-level protection action is a preventative, mild intervention. It alleviates the thermal stress on the IGBTs and prevents the temperature from rising further to a higher risk range without interrupting system operation and only slightly reducing load performance. Load reduction is chosen as the second-level protection action because its temperature control is stronger than frequency reduction, representing a moderate intervention. When mild frequency reduction is insufficient to suppress temperature rise, load reduction increases the intervention while still maintaining some load capacity, avoiding production line interruptions or equipment shutdowns caused by direct shutdown, thus balancing temperature control effectiveness and operational continuity. Shutdown is chosen as the third-level protection action because continued operation under severe thermal risk directly threatens device safety, causing irreversible equipment damage and economic losses. Ultimately, shutdown protection terminates power output, cutting off the heat source at its root, completely preventing further temperature increases, and protecting the IGBT modules and the entire inverter from permanent damage.

[0048] Optionally, the number of preset temperature threshold levels can be flexibly adjusted according to the needs of actual application scenarios, such as setting it to two, four or more levels; the specific forms of protection actions at each level can be equivalently replaced, for example, reducing the output operating frequency can be replaced by optimizing the PWM modulation strategy to reduce switching losses, reducing the output load power can be replaced by cutting off some non-core load branches, and shutdown protection can be replaced by switching to the backup bypass circuit to maintain basic operation; protection actions at each level can also be executed in combination, for example, frequency reduction and load reduction can be performed simultaneously in the second level of protection to further improve temperature control efficiency.

[0049] In some implementations, when the real-time temperature exceeds a second preset temperature threshold, the operating power of the magnetic levitation inverter's heat dissipation system is increased.

[0050] The heat dissipation system is a cooling device used in magnetic levitation frequency converters to dissipate the heat generated by the IGBT module. It includes forced air cooling systems, liquid cooling systems, etc. It removes the heat from the IGBT module through air flow or coolant circulation to maintain the device's operating temperature within a reasonable range.

[0051] The actual temperature of an IGBT module is determined by both the heat generation rate and the heat dissipation rate. Reducing the output load power only decreases heat generation from the heat generation side, which is a one-way temperature control. Increasing the operating power of the heat dissipation system accelerates heat dissipation from the heat dissipation side. The combination of the two can form a two-way temperature control effect, which can more quickly suppress the temperature rise and drive the temperature down. The heat dissipation power increase is set to be triggered by the second preset temperature threshold because the first level of thermal risk is relatively mild, and the temperature rise can be controlled by simply reducing the frequency without additional increase in heat dissipation power consumption, thus maintaining low heat dissipation energy consumption. When the thermal risk escalates to the moderate range, the heat dissipation power is then activated. This strengthens the temperature control and prevents the temperature from exceeding the third threshold and triggering shutdown. It also avoids the energy waste caused by ineffective increases in heat dissipation power during the low-risk stage, thus achieving a balance between temperature control capability and operating energy efficiency.

[0052] Specifically, when the system determines that the real-time temperature exceeds the second preset temperature threshold and enters the medium thermal risk range, the controller outputs an adjustment command to the drive component of the heat dissipation system to increase the operating power of the power component of the heat dissipation system and enhance the heat dissipation system's heat removal capability.

[0053] By setting three progressively increasing temperature thresholds and matching them with progressive protection actions from mild to severe, layered and precise intervention of IGBT thermal risks is achieved. This avoids the frequent operation interruptions caused by triggering severe protection at the slightest thermal risk in a single threshold scheme, as well as the problem of device overheating damage caused by insufficient protection. It can maintain the continuity of magnetic levitation frequency converter operation to the greatest extent while ensuring the long-term safe operation of IGBT devices, effectively balancing equipment reliability and production efficiency.

[0054] This invention solves the problem of delayed temperature control response and wasted computing power in traditional fixed sampling frequency schemes by dynamically adjusting the sampling frequency according to the rate of temperature change. At the same time, through a mechanism of matching multi-level temperature thresholds with corresponding protection levels, it realizes progressive temperature intervention under different thermal risk levels. It can ensure the safe operation of IGBT modules and avoid overheating damage, while taking into account the continuous operation of magnetic levitation frequency converters and system energy efficiency, and fully adapts to the operating characteristics of magnetic levitation systems with frequent load fluctuations and a wide dynamic range of operating conditions.

[0055] Figure 4The flowchart illustrates another embodiment of the IGBT temperature control method for a magnetic levitation frequency converter. The system first collects temperature changes at a 10-second reference cycle to obtain the temperature difference ΔT within that time period. Then, it enters the first-level judgment stage, comparing the temperature change ΔT within 10 seconds with a threshold of 0.3℃. If ΔT is not greater than 0.3℃, the system is determined to be in a stable temperature state, maintaining the current operating conditions and reference sampling frequency without initiating additional temperature control intervention, returning to the continuous temperature monitoring loop. If ΔT is greater than 0.3℃, the system is determined to be experiencing rapid temperature changes and a risk of excessive temperature rise. The system then increases the temperature sampling frequency to track temperature changes with a more frequent sampling frequency, subsequently entering the second-level graded temperature protection judgment stage. After adjusting the sampling frequency, the system acquires the real-time temperature of the IGBT at the increased sampling frequency and compares it progressively with three progressively increasing temperature thresholds: when the IGBT temperature exceeds 70°C, the system reduces the operating frequency by 10% to suppress temperature rise from the heat source side by reducing IGBT switching losses. If the temperature does not exceed 70°C, the system returns to the stable temperature maintenance branch. If the temperature continues to rise and exceeds 80°C after frequency reduction, the system further reduces the load by 20% to enhance temperature control by reducing output current and conduction losses. If the temperature continues to rise and exceeds 90°C after load reduction, the system finally triggers over-temperature protection shutdown, cutting off IGBT power output to completely terminate the heat source and prevent permanent thermal damage to the device.

[0056] In some embodiments, the method further includes a process of dynamically correcting the threshold for judging the rate of temperature change and the multi-level preset temperature thresholds. Specifically, this includes: collecting the electrical operating parameters of the magnetic levitation frequency converter and calculating the instantaneous loss of the IGBT in combination with a preset IGBT switching characteristic model; identifying the equivalent thermal impedance of the IGBT module online based on the instantaneous loss and the real-time temperature; comparing the equivalent thermal impedance with a preset thermal impedance reference value; and when the deviation between the equivalent thermal impedance and the preset thermal impedance reference value reaches a preset deviation threshold, dynamically correcting the threshold for judging the rate of temperature change and / or the multi-level preset temperature thresholds according to the ratio of the equivalent thermal impedance to the preset thermal impedance reference value.

[0057] Electrical operating parameters are electrical quantities that can be collected in real time during the operation of the magnetic levitation frequency converter. These include DC bus voltage, output phase current, IGBT on-state voltage drop, and switch drive status, reflecting IGBT operating losses. The IGBT switching characteristic model is a mathematical model describing the relationship between IGBT switching losses, conduction losses, and electrical parameters. It is built based on the physical characteristics and measured data of the IGBT device and is used for quantitative loss calculation. Instantaneous loss is the heat generated per unit time by the IGBT module under its current operating state. It consists of both conduction and switching losses and is the heat source input for the IGBT temperature rise. Equivalent thermal impedance is a comprehensive parameter characterizing the resistance to heat transfer along the heat dissipation path from the IGBT chip. A higher value indicates more difficult heat transfer and poorer heat dissipation capacity. Its value increases with factors such as heat sink fouling, reduced coolant flow, and aging of the device bonding layer. The preset thermal impedance reference value is a thermal impedance reference standard, usually corresponding to the standard thermal impedance value of the heat dissipation system under good working condition when the equipment leaves the factory. It serves as a reference for judging whether the thermal impedance deviates from the normal range. The preset deviation threshold is the maximum allowable deviation of the thermal impedance from the reference value. When the deviation exceeds this threshold, it is determined that the thermal characteristics of the heat dissipation system or device have changed significantly, and threshold correction needs to be initiated.

[0058] Specifically, the system collects various electrical operating parameters of the main circuit of the magnetic levitation frequency converter in real time. These parameters are then substituted into a preset IGBT switching characteristic model to calculate the IGBT's conduction and switching losses. The sum of these two losses yields the instantaneous loss value of the IGBT under the current operating condition. The instantaneous loss data over a continuous period is matched with the corresponding real-time temperature data. A parameter identification algorithm is used to calculate the equivalent thermal impedance value of the current IGBT module, enabling online real-time updates of the thermal impedance. The difference or ratio between the current equivalent thermal impedance and a preset reference value is calculated to obtain the deviation amplitude. When the deviation amplitude reaches a preset deviation threshold, the ratio of the equivalent thermal impedance to the reference value is used as a correction coefficient to dynamically adjust one or more of the following: the temperature change rate judgment threshold and multiple preset temperature thresholds.

[0059] Fixed temperature control thresholds are set based on ideal heat dissipation conditions at the factory. When the equivalent thermal resistance increases and the heat dissipation capacity decreases, the thermal risk of the device corresponding to the same temperature or rate of temperature rise will increase significantly. If the original threshold is still used, there will be a risk of protection lag and device overheating damage. Synchronously correcting the temperature control threshold according to the deviation ratio of thermal resistance allows the protection threshold to be dynamically matched with the current actual heat dissipation capacity. The worse the heat dissipation capacity, the earlier the protection triggers, always maintaining a reasonable safety margin. At the same time, this correction mechanism can also avoid false protection triggers caused by temporary fluctuations in the heat dissipation system. Correction is only performed when the thermal resistance deviates continuously and excessively, ensuring the stability of system operation.

[0060] In some embodiments, the method further includes: periodically calculating the temperature cycle amplitude and temperature dwell time of the IGBT, and cumulatively calculating the thermal fatigue damage of the IGBT; obtaining the remaining service life of the IGBT based on the thermal fatigue damage; comparing the remaining service life with a multi-level preset service life threshold to determine the service life range in which the remaining service life is located; adjusting the values ​​of the multi-level preset temperature thresholds according to the corresponding service life range, and correspondingly limiting the maximum operating power of the magnetic levitation frequency converter.

[0061] Temperature cycling amplitude is the difference between the highest and lowest temperatures reached by the IGBT module during a single temperature fluctuation. A larger amplitude indicates stronger thermal stress and more significant fatigue damage to the device. Temperature dwell time is the duration the IGBT module maintains a specific temperature range. Longer high-temperature dwell times lead to faster accumulation of thermal fatigue damage. Thermal fatigue damage is a quantified value of the accumulated thermal stress damage caused by repeated temperature changes in the IGBT module. The more temperature cycles, the larger the amplitude, and the longer the high-temperature dwell time during long-term operation, the higher the thermal fatigue damage and the more severe the device aging. Remaining service life is the estimated duration or number of cycles the IGBT module can continue to operate safely based on the current level of thermal fatigue damage and degradation rate, characterizing the device's remaining health and service capability. Multi-level preset lifespan thresholds are used to divide the device aging process into multiple different lifespan ranges, corresponding to different management strategies.

[0062] Specifically, the system cyclically identifies the collected IGBT temperature time-series data according to a preset statistical cycle, statistically analyzes the amplitude and duration of each temperature cycle, and calculates the damage caused by a single temperature cycle using a thermal fatigue damage model. This single-cycle damage is then continuously accumulated to obtain the total accumulated thermal fatigue damage of the IGBT module. The current accumulated thermal fatigue damage is then compared with the device's failure damage threshold and historical degradation rate to obtain the remaining service life of the IGBT module. The calculation formula is as follows:

[0063]

[0064] in, This represents the remaining service life at the current moment. This represents the health status corresponding to thermal fatigue damage at the current moment; the higher the value, the deeper the degree of aging. This represents the upper limit of the health status threshold corresponding to device failure. The rate of decline in current health status is the rate at which damage increases per unit time or per cycle.

[0065] The calculated remaining service life value is compared with the preset multi-level service life thresholds one by one to determine the range within which the current remaining service life falls. Based on the current service life range, the corresponding control strategy is matched, the trigger values ​​of the multi-level preset temperature thresholds are adjusted, and the upper limit of the maximum output power of the inverter at the corresponding level is set.

[0066] For example, taking a magnetic levitation cooling inverter that has been running continuously for many years as an example, in the early stage of equipment commissioning, the thermal fatigue damage of the IGBT module is low, and the remaining service life is in the highest range. The system maintains the original temperature protection threshold and rated power limit to ensure the equipment's full-load operation capability. As the temperature cycle accumulates continuously during long-term operation, when the remaining service life drops to the moderate aging range, the system adjusts the temperature protection threshold accordingly to enable the protection action to intervene earlier. At the same time, the maximum operating power of the inverter is limited to a certain percentage of the rated power to reduce the severe temperature rise and thermal stress impact caused by large load fluctuations. When the remaining service life further drops to the severe aging range, the system further tightens the temperature threshold and power limit to force the device to operate under milder conditions until a planned shutdown for maintenance is arranged.

[0067] By assessing the cumulative thermal fatigue damage and remaining lifespan, dynamic safety margin control of the IGBT module throughout its entire lifecycle is achieved. This allows for adaptive adjustment of protection strategies and operating boundaries based on the real-time aging level of the devices. It solves the problem that traditional fixed threshold solutions cannot adapt to device aging and degradation, and that there are high safety risks at the end of the lifespan. This effectively reduces the probability of sudden device failure and avoids unnecessary forced shutdowns. Under the premise of ensuring operational safety, it extends the effective service life of the equipment and improves the operational reliability and economy of the magnetic levitation frequency converter throughout its entire lifecycle.

[0068] The technical solution of this embodiment first collects temperature data at a reference sampling frequency, then adaptively adjusts the temperature sampling frequency based on the temperature change rate, and then obtains the real-time temperature at the adjusted sampling frequency. By comparing the real-time temperature with the multi-level preset temperature thresholds, the corresponding level of temperature protection operation is executed. This can effectively improve the temperature control response accuracy under dynamic operating conditions, improve the system's operating energy efficiency, and achieve synergistic optimization of IGBT operating safety and inverter operating continuity.

[0069] According to an embodiment of the present invention, a magnetic levitation inverter IGBT temperature control device corresponding to the magnetic levitation inverter IGBT temperature control method is also provided. See also Figure 2 The schematic diagram shown is a structural diagram of an embodiment of the device of the present invention. The magnetic levitation frequency converter IGBT temperature control device may include: a data acquisition unit 101 and a protection unit 102.

[0070] The acquisition unit 101 is configured to acquire temperature data of the IGBT module at a reference sampling frequency.

[0071] The reference sampling frequency is the periodic frequency at which temperature data is collected under the system's default state, such as 10 seconds, suitable for steady-state, low-temperature rise rate normal operating conditions. Under normal operating conditions with stable load and gradual temperature rise, the thermal state of the IGBT module changes slowly, and a lower sampling frequency can meet the basic requirements of temperature monitoring. Using a reference sampling frequency can reduce the sampling operation overhead of the controller, reduce the continuous power consumption of the sampling circuit, and balance basic monitoring capabilities with system operating energy efficiency. Specifically, when the system powers on and enters normal operating state, it periodically collects temperature data from the IGBT module according to the preset reference sampling period to obtain continuous temperature time-series values.

[0072] The acquisition unit 101 is further configured to determine the temperature change rate based on the temperature data and adjust the temperature sampling frequency of the IGBT module based on the temperature change rate.

[0073] The rate of temperature change is the amount of temperature change in an IGBT module per unit time. It characterizes how quickly the IGBT temperature rises or falls, reflecting the severity of changes in heat load. A faster rate of temperature rise indicates more drastic load fluctuations and a faster increase in heat load, thus increasing the risk of temperature overshoot. Traditional fixed-frequency sampling schemes either waste computing power by using high-frequency sampling throughout or fail to capture transient temperature rises by using low-frequency sampling throughout. By adjusting the sampling frequency in conjunction with the rate of temperature change, low-frequency sampling can be maintained during periods of gradual temperature rise to save energy and computing power, while the sampling frequency can be automatically increased during periods of rapid temperature rise to improve real-time monitoring, achieving adaptive matching between the sampling strategy and operating conditions.

[0074] Specifically, the system performs interpolation on multiple sets of continuously acquired temperature data to calculate the temperature change per unit time, thus obtaining the rate of temperature change. For example, the formula for calculating the rate of temperature change is ΔT / Δt=(T n -T n-10 ) / 10, where T n T represents the current temperature. n-10 The temperature value is from 10 seconds ago. The rate of temperature change is then used as a criterion to adjust the temperature sampling period and frequency accordingly.

[0075] In some embodiments, the acquisition unit 101 adjusts the temperature sampling frequency of the IGBT module according to the temperature change rate, including: comparing the temperature change rate with a preset rate threshold; increasing the temperature sampling frequency when the temperature change rate is greater than the preset rate threshold; and maintaining the reference temperature sampling frequency when the temperature change rate is not greater than the preset rate threshold.

[0076] A preset rate threshold (e.g., 0.3℃ / s) is used to determine whether the current IGBT temperature rise is too rapid and whether there is a risk of transient overheating. Specifically, after calculating the current temperature change rate, the system compares this value with the pre-stored preset rate threshold. If the comparison result shows that the current temperature change rate is higher than the preset rate threshold, the system adjusts the temperature acquisition timer configuration, shortens the sampling period, and increases the number of temperature acquisitions per unit time (e.g., the frequency is increased to 1 second / time). If the comparison result shows that the current temperature change rate does not exceed the preset rate threshold, the system maintains the original baseline sampling period and continues to acquire temperature data at the default frequency.

[0077] By adjusting the temperature sampling frequency, a low-power, low-computing-overhead sampling configuration can be maintained when the IGBT temperature rises slowly, and the sampling density can be automatically increased when the temperature rises too quickly to enhance the temperature control response capability. This solves both the resource waste problem caused by traditional fixed high-frequency sampling and the temperature control response lag problem caused by fixed low-frequency sampling. Without increasing hardware costs, it simultaneously takes into account the system's energy efficiency and the real-time performance of temperature monitoring.

[0078] The acquisition unit 101 is also configured to acquire the real-time temperature of the IGBT module at an adjusted sampling frequency.

[0079] The accuracy and timeliness of temperature protection actions highly depend on the real-time nature of the temperature acquisition data. When the sampling frequency is matched with the current temperature rise conditions, the acquired real-time temperature can more accurately reflect the true thermal state of the IGBT, avoiding problems such as missed temperature peaks and delayed judgments due to excessively long sampling intervals. Specifically, the system continuously acquires the current temperature value of the IGBT module according to the adjusted sampling period.

[0080] The protection unit 102 is configured to compare the real-time temperature with multiple preset temperature thresholds and perform temperature protection operations of the corresponding level based on the comparison results.

[0081] The thermal risk of IGBT modules increases gradually with rising temperature, and the risk of device damage and temperature control requirements differ across different temperature ranges. Protection schemes with a single temperature threshold can only trigger a single action, either causing excessive intervention in low-risk stages that impacts equipment operation, or insufficient intervention in high-risk stages that leads to device damage. Adopting a multi-level threshold approach with corresponding multi-level protection enables progressive temperature intervention: mild intervention at lower temperatures to ensure continuous equipment operation, and severe intervention at higher temperatures to ensure device safety, thus balancing operational reliability and equipment efficiency.

[0082] Specifically, the system compares the collected real-time temperature values ​​with a series of pre-set, progressively increasing temperature thresholds to determine the temperature range in which the real-time temperature falls; based on the thermal risk level corresponding to the temperature range, it outputs the corresponding temperature control protection command and executes the appropriate intervention action.

[0083] In some embodiments, the multi-level preset temperature thresholds include a first preset temperature threshold, a second preset temperature threshold, and a third preset temperature threshold, which increase progressively. The protection unit 102 compares the real-time temperature with the multi-level preset temperature thresholds and performs corresponding level temperature protection operations based on the comparison results, including: reducing the output operating frequency of the magnetic levitation inverter when the real-time temperature exceeds the first preset temperature threshold; reducing the output load power of the magnetic levitation inverter when the real-time temperature exceeds the second preset temperature threshold; and triggering the magnetic levitation inverter shutdown protection when the real-time temperature exceeds the third preset temperature threshold.

[0084] Specifically, when the system determines that the real-time temperature is higher than the first preset temperature threshold but lower than the second preset temperature threshold, the controller sends a frequency adjustment command to the inverter drive module, reducing the inverter's output operating frequency by a preset ratio. When the system determines that the real-time temperature is higher than the second preset temperature threshold but lower than the third preset temperature threshold, the controller sends a power adjustment command to the load control module, reducing the inverter's output load power by a preset ratio. When the system determines that the real-time temperature is higher than the third preset temperature threshold, the controller immediately outputs a fault shutdown command, cutting off the gate drive power of all IGBT modules, stopping power output, and putting the inverter into a safe shutdown state.

[0085] Choosing frequency reduction as the first-level protection action is a preventative, mild intervention. It alleviates the thermal stress on the IGBTs and prevents the temperature from rising further to a higher risk range without interrupting system operation and only slightly reducing load performance. Load reduction is chosen as the second-level protection action because its temperature control is stronger than frequency reduction, representing a moderate intervention. When mild frequency reduction is insufficient to suppress temperature rise, load reduction increases the intervention while still maintaining some load capacity, avoiding production line interruptions or equipment shutdowns caused by direct shutdown, thus balancing temperature control effectiveness and operational continuity. Shutdown is chosen as the third-level protection action because continued operation under severe thermal risk directly threatens device safety, causing irreversible equipment damage and economic losses. Ultimately, shutdown protection terminates power output, cutting off the heat source at its root, completely preventing further temperature increases, and protecting the IGBT modules and the entire inverter from permanent damage.

[0086] In some implementations, when the real-time temperature exceeds a second preset temperature threshold, the operating power of the magnetic levitation inverter's heat dissipation system is increased.

[0087] The heat dissipation system is a cooling device used in magnetic levitation frequency converters to dissipate the heat generated by the IGBT module. It includes forced air cooling systems, liquid cooling systems, etc. It removes the heat from the IGBT module through air flow or coolant circulation to maintain the device's operating temperature within a reasonable range.

[0088] The actual temperature of an IGBT module is determined by both the heat generation rate and the heat dissipation rate. Reducing the output load power only decreases heat generation from the heat generation side, which is a one-way temperature control. Increasing the operating power of the heat dissipation system accelerates heat dissipation from the heat dissipation side. The combination of the two can form a two-way temperature control effect, which can more quickly suppress the temperature rise and drive the temperature down. The heat dissipation power increase is set to be triggered by the second preset temperature threshold because the first level of thermal risk is relatively mild, and the temperature rise can be controlled by simply reducing the frequency without additional increase in heat dissipation power consumption, thus maintaining low heat dissipation energy consumption. When the thermal risk escalates to the moderate range, the heat dissipation power is then activated. This strengthens the temperature control and prevents the temperature from exceeding the third threshold and triggering shutdown. It also avoids the energy waste caused by ineffective increases in heat dissipation power during the low-risk stage, thus achieving a balance between temperature control capability and operating energy efficiency.

[0089] Specifically, when the system determines that the real-time temperature exceeds the second preset temperature threshold and enters the medium thermal risk range, the controller outputs an adjustment command to the drive component of the heat dissipation system to increase the operating power of the power component of the heat dissipation system and enhance the heat dissipation system's heat removal capability.

[0090] By setting three progressively increasing temperature thresholds and matching them with progressive protection actions from mild to severe, layered and precise intervention of IGBT thermal risks is achieved. This avoids the frequent operation interruptions caused by triggering severe protection at the slightest thermal risk in a single threshold scheme, as well as the problem of device overheating damage caused by insufficient protection. It can maintain the continuity of magnetic levitation frequency converter operation to the greatest extent while ensuring the long-term safe operation of IGBT devices, effectively balancing equipment reliability and production efficiency.

[0091] This invention solves the problem of delayed temperature control response and wasted computing power in traditional fixed sampling frequency schemes by dynamically adjusting the sampling frequency according to the rate of temperature change. At the same time, through a mechanism of matching multi-level temperature thresholds with corresponding protection levels, it realizes progressive temperature intervention under different thermal risk levels. It can ensure the safe operation of IGBT modules and avoid overheating damage, while taking into account the continuous operation of magnetic levitation frequency converters and system energy efficiency, and fully adapts to the operating characteristics of magnetic levitation systems with frequent load fluctuations and a wide dynamic range of operating conditions.

[0092] In some embodiments, the protection unit 102 is further configured to: collect the electrical operating parameters of the magnetic levitation frequency converter, calculate the instantaneous loss of the IGBT in conjunction with a preset IGBT switching characteristic model; identify the equivalent thermal impedance of the IGBT module online based on the instantaneous loss and the real-time temperature; compare the equivalent thermal impedance with a preset thermal impedance reference value; and when the deviation between the equivalent thermal impedance and the preset thermal impedance reference value reaches a preset deviation threshold, dynamically correct the judgment threshold for the rate of temperature change and / or multiple preset temperature thresholds according to the ratio of the equivalent thermal impedance to the preset thermal impedance reference value.

[0093] Electrical operating parameters are electrical quantities that can be collected in real time during the operation of the magnetic levitation frequency converter. These include DC bus voltage, output phase current, IGBT on-state voltage drop, and switch drive status, reflecting IGBT operating losses. The IGBT switching characteristic model is a mathematical model describing the relationship between IGBT switching losses, conduction losses, and electrical parameters. It is built based on the physical characteristics and measured data of the IGBT device and is used for quantitative loss calculation. Instantaneous loss is the heat generated per unit time by the IGBT module under its current operating state. It consists of both conduction and switching losses and is the heat source input for the IGBT temperature rise. Equivalent thermal impedance is a comprehensive parameter characterizing the resistance to heat transfer along the heat dissipation path from the IGBT chip. A higher value indicates more difficult heat transfer and poorer heat dissipation capacity. Its value increases with factors such as heat sink fouling, reduced coolant flow, and aging of the device bonding layer. The preset thermal impedance reference value is a thermal impedance reference standard, usually corresponding to the standard thermal impedance value of the heat dissipation system under good working condition when the equipment leaves the factory. It serves as a reference for judging whether the thermal impedance deviates from the normal range. The preset deviation threshold is the maximum allowable deviation of the thermal impedance from the reference value. When the deviation exceeds this threshold, it is determined that the thermal characteristics of the heat dissipation system or device have changed significantly, and threshold correction needs to be initiated.

[0094] Specifically, the system collects various electrical operating parameters of the main circuit of the magnetic levitation frequency converter in real time. These parameters are then substituted into a preset IGBT switching characteristic model to calculate the IGBT's conduction and switching losses. The sum of these two losses yields the instantaneous loss value of the IGBT under the current operating condition. The instantaneous loss data over a continuous period is matched with the corresponding real-time temperature data. A parameter identification algorithm is used to calculate the equivalent thermal impedance value of the current IGBT module, enabling online real-time updates of the thermal impedance. The difference or ratio between the current equivalent thermal impedance and a preset reference value is calculated to obtain the deviation amplitude. When the deviation amplitude reaches a preset deviation threshold, the ratio of the equivalent thermal impedance to the reference value is used as a correction coefficient to dynamically adjust one or more of the following: the temperature change rate judgment threshold and multiple preset temperature thresholds.

[0095] Fixed temperature control thresholds are set based on ideal heat dissipation conditions at the factory. When the equivalent thermal resistance increases and the heat dissipation capacity decreases, the thermal risk of the device corresponding to the same temperature or rate of temperature rise will increase significantly. If the original threshold is still used, there will be a risk of protection lag and device overheating damage. Synchronously correcting the temperature control threshold according to the deviation ratio of thermal resistance allows the protection threshold to be dynamically matched with the current actual heat dissipation capacity. The worse the heat dissipation capacity, the earlier the protection triggers, always maintaining a reasonable safety margin. At the same time, this correction mechanism can also avoid false protection triggers caused by temporary fluctuations in the heat dissipation system. Correction is only performed when the thermal resistance deviates continuously and excessively, ensuring the stability of system operation.

[0096] In some embodiments, the protection unit 102 is further configured to: periodically count the temperature cycle amplitude and temperature dwell time of the IGBT, and cumulatively calculate the thermal fatigue damage of the IGBT; obtain the remaining service life of the IGBT based on the thermal fatigue damage; compare the remaining service life with a multi-level preset service life threshold to determine the service life range in which the remaining service life is located; adjust the values ​​of the multi-level preset temperature thresholds according to the corresponding service life range, and correspondingly limit the maximum operating power of the magnetic levitation frequency converter.

[0097] Temperature cycling amplitude is the difference between the highest and lowest temperatures reached by the IGBT module during a single temperature fluctuation. A larger amplitude indicates stronger thermal stress and more significant fatigue damage to the device. Temperature dwell time is the duration the IGBT module maintains a specific temperature range. Longer high-temperature dwell times lead to faster accumulation of thermal fatigue damage. Thermal fatigue damage is a quantified value of the accumulated thermal stress damage caused by repeated temperature changes in the IGBT module. The more temperature cycles, the larger the amplitude, and the longer the high-temperature dwell time during long-term operation, the higher the thermal fatigue damage and the more severe the device aging. Remaining service life is the estimated duration or number of cycles the IGBT module can continue to operate safely based on the current level of thermal fatigue damage and degradation rate, characterizing the device's remaining health and service capability. Multi-level preset lifespan thresholds are used to divide the device aging process into multiple different lifespan ranges, corresponding to different management strategies.

[0098] Specifically, the system cyclically identifies the collected IGBT temperature time-series data according to a preset statistical cycle, statistically analyzes the amplitude and duration of each temperature cycle, and calculates the damage caused by a single temperature cycle using a thermal fatigue damage model. This single-cycle damage is then continuously accumulated to obtain the total accumulated thermal fatigue damage of the IGBT module. The current accumulated thermal fatigue damage is then compared with the device's failure damage threshold and historical degradation rate to obtain the remaining service life of the IGBT module. The calculation formula is as follows:

[0099]

[0100] in, This represents the remaining service life at the current moment. This represents the health status corresponding to thermal fatigue damage at the current moment; the higher the value, the deeper the degree of aging. This represents the upper limit of the health status threshold corresponding to device failure. The rate of decline in current health status is the rate at which damage increases per unit time or per cycle.

[0101] The calculated remaining service life value is compared with the preset multi-level service life thresholds one by one to determine the range within which the current remaining service life falls. Based on the current service life range, the corresponding control strategy is matched, the trigger values ​​of the multi-level preset temperature thresholds are adjusted, and the upper limit of the maximum output power of the inverter at the corresponding level is set.

[0102] By assessing the cumulative thermal fatigue damage and remaining lifespan, dynamic safety margin control of the IGBT module throughout its entire lifecycle is achieved. This allows for adaptive adjustment of protection strategies and operating boundaries based on the real-time aging level of the devices. It solves the problem that traditional fixed threshold solutions cannot adapt to device aging and degradation, and that there are high safety risks at the end of the lifespan. This effectively reduces the probability of sudden device failure and avoids unnecessary forced shutdowns. Under the premise of ensuring operational safety, it extends the effective service life of the equipment and improves the operational reliability and economy of the magnetic levitation frequency converter throughout its entire lifecycle.

[0103] Since the processing and functions implemented by the device in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0104] By employing the technical solution of this invention, when controlling the temperature of the IGBT module of a magnetic levitation frequency converter, temperature data is first collected at a reference sampling frequency, and the temperature sampling frequency is dynamically adjusted according to the temperature change rate. Then, the real-time temperature is collected at the adjusted sampling frequency, and the corresponding level of temperature protection action is triggered by comparing the results of multiple preset temperature thresholds. This can improve the temperature control response speed and accuracy under dynamic load, reduce unnecessary operating energy consumption, and balance the operating safety of the IGBT and the operating stability of the frequency converter.

[0105] According to an embodiment of the present invention, a magnetic levitation inverter control system corresponding to the IGBT temperature control device of the magnetic levitation inverter is also provided. This magnetic levitation inverter control system may include the magnetic levitation inverter IGBT temperature control device described above.

[0106] Since the processing and functions implemented by the magnetic levitation frequency converter control system in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned device, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0107] The technical solution of this invention first uses a reference sampling frequency to collect temperature data, then adaptively matches the temperature sampling frequency according to the rate of temperature change, and then collects real-time temperature at the matched sampling frequency. The corresponding level of temperature protection measures are then executed in accordance with multiple preset temperature thresholds. This can significantly improve the temperature control response capability under fluctuating operating conditions, optimize the overall energy efficiency of the system, and at the same time ensure the safe operation of IGBTs and the continuous operation capability of the frequency converter.

[0108] According to an embodiment of the present invention, a storage medium corresponding to the IGBT temperature control method for a magnetic levitation inverter is also provided. The storage medium includes a stored program, wherein the program controls the device where the storage medium is located to execute the above-described magnetic levitation inverter IGBT temperature control method during operation.

[0109] Since the processing and functions implemented by the storage medium in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0110] The technical solution of this invention first collects temperature data at a reference sampling frequency, dynamically adjusts the temperature sampling frequency according to the rate of temperature change, and then obtains the real-time temperature at the adjusted sampling frequency. Based on the comparison results between the real-time temperature and multiple preset temperature thresholds, the corresponding level of temperature protection operation is executed. This can effectively improve the temperature control response accuracy under dynamic operating conditions, improve the system's energy efficiency, and take into account both the thermal safety of IGBTs and the continuous operation of the frequency converter.

[0111] According to an embodiment of the present invention, a computer program product corresponding to the IGBT temperature control method for a magnetic levitation inverter is also provided. The computer program product includes a computer program that, when processed and executed, implements the steps of the above-described magnetic levitation inverter IGBT temperature control method.

[0112] Since the processing and functions implemented by the computer program product in this embodiment are basically corresponding to the embodiments, principles and examples of the aforementioned methods, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0113] The technical solution of this invention first collects temperature data at a reference sampling frequency, then adaptively adjusts the temperature sampling frequency based on the rate of temperature change, and then collects real-time temperature at the adjusted sampling frequency. Based on the comparison results of multiple preset temperature thresholds, the corresponding level of temperature protection action is activated. This can improve the timeliness of temperature control response under dynamic load fluctuations, enhance system operating efficiency, and achieve dual protection for IGBT safe operation and inverter stable operation.

[0114] In summary, it is readily understood by those skilled in the art that, without conflict, the aforementioned advantageous methods can be freely combined and superimposed.

[0115] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for temperature control of IGBT in a magnetic levitation frequency converter, characterized in that, include: Temperature data of the IGBT module is acquired at a reference sampling frequency; The temperature change rate is determined based on the temperature data, and the temperature sampling frequency of the IGBT module is adjusted based on the temperature change rate. The real-time temperature of the IGBT module is acquired using the adjusted sampling frequency; The real-time temperature is compared with multiple preset temperature thresholds, and the corresponding level of temperature protection operation is executed based on the comparison result.

2. The IGBT temperature control method for a magnetic levitation frequency converter according to claim 1, characterized in that, Adjusting the temperature sampling frequency of the IGBT module according to the rate of temperature change includes: The rate of temperature change is compared with a preset rate threshold. When the rate of temperature change exceeds the preset rate threshold, the temperature sampling frequency is increased; When the rate of temperature change is not greater than the preset rate threshold, the reference temperature sampling frequency is maintained.

3. The IGBT temperature control method for a magnetic levitation frequency converter according to claim 1, characterized in that, The multi-level preset temperature thresholds include a first preset temperature threshold, a second preset temperature threshold, and a third preset temperature threshold that increase progressively. The real-time temperature is compared with multiple preset temperature thresholds, and the corresponding level of temperature protection operation is executed based on the comparison result, including: When the real-time temperature exceeds the first preset temperature threshold, reduce the output operating frequency of the magnetic levitation frequency converter; When the real-time temperature exceeds the second preset temperature threshold, reduce the output load power of the magnetic levitation frequency converter; When the real-time temperature exceeds the third preset temperature threshold, the magnetic levitation frequency converter is triggered to stop.

4. The IGBT temperature control method for a magnetic levitation frequency converter according to claim 3, characterized in that, When the real-time temperature exceeds the second preset temperature threshold, the operating power of the magnetic levitation inverter heat dissipation system is increased.

5. The IGBT temperature control method for a magnetic levitation frequency converter according to any one of claims 1 to 4, characterized in that, The method further includes: The electrical operating parameters of the magnetic levitation frequency converter are collected, and the instantaneous loss of the IGBT is calculated by combining the preset IGBT switching characteristic model. Based on the instantaneous loss and the real-time temperature, the equivalent thermal impedance of the IGBT module is identified online. The equivalent thermal impedance is compared with a preset thermal impedance reference value. When the deviation between the equivalent thermal impedance and the preset thermal impedance reference value reaches a preset deviation threshold, the judgment threshold for the rate of temperature change and / or multiple preset temperature thresholds are dynamically corrected according to the ratio of the equivalent thermal impedance to the preset thermal impedance reference value.

6. The IGBT temperature control method for a magnetic levitation frequency converter according to any one of claims 1 to 4, characterized in that, The method further includes: The temperature cycling amplitude and temperature dwell time of the IGBT are periodically statistically analyzed, and the thermal fatigue damage of the IGBT is calculated cumulatively. The remaining service life of the IGBT is obtained based on the amount of thermal fatigue damage. The remaining service life is compared with a multi-level preset service life threshold to determine the service life range in which the remaining service life is located. Based on the corresponding lifespan range, the values ​​of the multi-level preset temperature thresholds are adjusted, and the maximum operating power of the magnetic levitation frequency converter is limited accordingly.

7. A temperature control device for an IGBT in a magnetic levitation frequency converter, characterized in that, include: The acquisition unit is configured to acquire temperature data from the IGBT module at a reference sampling frequency. The acquisition unit is also configured to determine the temperature change rate based on the temperature data and adjust the temperature sampling frequency of the IGBT module based on the temperature change rate. The acquisition unit is also configured to acquire the real-time temperature of the IGBT module at an adjusted sampling frequency; The protection unit is configured to compare the real-time temperature with multiple preset temperature thresholds and perform temperature protection operations of the corresponding level based on the comparison results.

8. A magnetic levitation frequency converter control system, characterized in that, include: The magnetic levitation frequency converter IGBT temperature control device as described in claim 7.

9. A storage medium, characterized in that, The storage medium includes a stored program, wherein, when the program is executed, the device containing the storage medium is controlled to perform the magnetic levitation inverter IGBT temperature control method as described in any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the magnetic levitation inverter IGBT temperature control method as described in any one of claims 1 to 6.

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