Control method and control system of variable-frequency power supply and related equipment of variable-frequency power supply

Abstract

The invention relates to a variable-frequency power supply control method and system and related equipment thereof, and relates to the technical field of frequency converter control. The method comprises the following steps: in response to starting operation of a variable-frequency power supply, generating an SPWM signal based on an SPWM module to drive and control an IGBT in the variable-frequency power supply so as to output sine-wave voltage; obtaining an IGBT temperature and an environment temperature in an IGBT operation process, determining an IGBT temperature rise according to the IGBT temperature and the environment temperature, and determining a target carrier wave ratio according to the IGBT temperature rise; and adjusting the SPWM signal according to the target carrier wave ratio, and driving on and off of the IGBT according to the adjusted SPWM signal so as to realize temperature rise control of the IGBT. According to the method, the switching loss of the IGBT is reduced, the temperature rise of the IGBT is dynamically controlled, the efficiency of equipment is improved, and the service life of the equipment is prolonged.

Description

Technical Field

[0001] The present application relates to the field of inverter control technology, and in particular to a control method and control system for a variable frequency power supply and related equipment. Background Art

[0002] In the field of power electronics technology, the conversion and control of DC voltage is one of the important research directions. For example, the pulse width modulation signal generated by the pulse width modulation technology is used to drive and control the on and off of the power switching device IGBT (Insulated Gate Bipolar Transistor) in the variable frequency drive (VFD), thereby outputting a sinusoidal AC voltage. Although during the pulse width modulation process, the IGBT current gradually increases from zero at the moment of conduction, and the conduction loss is small, the voltage and current at the moment of IGBT shutdown are large, and there is a large turn-off loss. Because the switching loss of the power switching device IGBT is too high during the repeated on and off process, on the one hand, it affects the efficiency and service life of the equipment. On the other hand, excessive switching loss will cause the IGBT to heat up quickly, thereby affecting the operation effect of the equipment.

[0003] In the related art, temperature sensors are generally arranged to prevent IGBT from overheating by setting a fixed upper temperature limit.

[0004] Because the switching frequency of IGBT is relatively fast during the DC voltage conversion process of variable frequency power supply, especially high voltage variable frequency power supply,

[0005] The switching loss is high, which leads to faster temperature rise. The related technology-based approach cannot be dynamically adjusted according to the actual operation of the equipment, which may cause the equipment to overheat or consume too much energy. How to effectively control the variable frequency power supply to reduce the switching loss of the IGBT and dynamically control the temperature rise of the IGBT while ensuring the output of the sine wave voltage, thereby improving the operating efficiency of the variable frequency power supply and IGBT, reducing operating energy consumption, and extending the service life of the equipment is an issue that needs to be solved urgently.

[0006] With respect to the above-mentioned problems in the related technologies, no effective solutions have been proposed yet. Summary of the invention

[0007] A control method and control system for a variable frequency power supply and related equipment provided by an embodiment of the present invention at least solve the problems in the related art that the switching loss of the IGBT in the variable frequency power supply is high, the temperature rise control effect of the IGBT is poor, and dynamic control cannot be performed according to the actual operation conditions of the equipment, which leads to low equipment operation efficiency, high energy consumption and short service life.

[0008] In order to solve the above problem, one aspect of an embodiment of the present invention provides a control method for a variable frequency power supply, comprising:

[0009] In response to the start-up operation of the variable frequency power supply, the SPWM module generates an SPWM signal to drive and control the IGBT in the variable frequency power supply to output a sinusoidal wave voltage;

[0010] Acquire the IGBT temperature and the ambient temperature during the operation of the IGBT, determine the IGBT temperature rise according to the IGBT temperature and the ambient temperature, and determine the target carrier ratio according to the IGBT temperature rise;

[0011] The SPWM signal is adjusted according to the target carrier ratio, and the IGBT is driven to be turned on and off according to the adjusted SPWM signal to achieve temperature rise control of the IGBT.

[0012] In some embodiments, the step of determining the IGBT temperature rise according to the IGBT temperature and the ambient temperature, and determining the target carrier ratio according to the IGBT temperature rise further includes:

[0013] Calculate the difference between the IGBT temperature and the ambient temperature to get the IGBT temperature rise;

[0014] Determine whether the IGBT temperature rise exceeds the temperature rise threshold. If so, determine the carrier ratio reduction ratio based on the ratio of the IGBT temperature rise exceeding the temperature rise threshold, and determine the target carrier ratio based on the current carrier ratio and the carrier ratio reduction ratio.

[0015] In some of these embodiments, the method further comprises:

[0016] The secondary side current value of the variable frequency power supply is obtained, and the temperature rise threshold is adjusted according to the secondary side current value; if the secondary side current value is greater than or equal to the current threshold, the temperature rise threshold is adjusted lower; if the secondary side current value is less than the current threshold, the temperature rise threshold is adjusted higher.

[0017] In some of these embodiments, the method further comprises:

[0018] The target carrier ratio is updated according to the IGBT temperature rise and the adjusted temperature threshold, and the SPWM signal is adjusted according to the updated target carrier ratio.

[0019] In some of the embodiments, if the IGBT temperature exceeds a temperature threshold or the IGBT temperature rise exceeds a temperature rise threshold, the method further includes: reducing the output power or output current of the variable frequency power supply.

[0020] In some embodiments, the step of determining the target carrier ratio according to the IGBT temperature rise further includes:

[0021] Obtain a mapping table of temperature rise-carrier ratio, and determine the target carrier ratio according to the mapping table and the IGBT temperature rise.

[0022] In some of the embodiments, the method further includes the step of constructing a mapping table of temperature rise-carrier ratio:

[0023] Obtaining the upper temperature limit of the IGBT, selecting multiple IGBT sample temperatures that do not exceed the upper temperature limit of the IGBT, and determining the corresponding IGBT sample temperature rise;

[0024] Determine the carrier ratio interval based on the maximum switching frequency of the IGBT in the variable frequency power supply, the filter model, and the operating frequency range of the transformer;

[0025] For any IGBT sample temperature rise, multiple sample carrier ratios are set in the carrier ratio interval, and the SPWM signal is adjusted according to the sample carrier ratio to obtain the IGBT test temperature rise at the next preset moment, and the optimal sample carrier ratio corresponding to the IGBT sample temperature rise is determined according to the IGBT test temperature rise;

[0026] A linear fitting process is performed on the temperature rises of multiple IGBT samples and their corresponding optimal sample carrier ratios, and a temperature rise-carrier ratio mapping table is constructed according to the linear fitting process results.

[0027] In some embodiments, the IGBT temperature is obtained by a temperature sensor arranged in a heat sink corresponding to the IGBT, and the ambient temperature is obtained by a temperature sensor arranged in a control cabinet of the variable frequency power supply; and the step of determining the IGBT temperature rise according to the IGBT temperature and the ambient temperature further includes:

[0028] Obtaining IGBT parameters, and calculating the first temperature rise corresponding to the IGBT according to the IGBT parameters; wherein the IGBT parameters include a thermal resistance value corresponding to the IGBT, a current value flowing through the IGBT, a heat dissipation area, and a thermal conductivity;

[0029] Calculate the difference between the IGBT temperature and the ambient temperature to obtain the second temperature rise corresponding to the IGBT;

[0030] The first temperature rise and the second temperature rise are added to obtain the IGBT temperature rise.

[0031] In some embodiments, the SPWM signal is a bipolar SPWM signal.

[0032] In order to solve the above problem, one aspect of an embodiment of the present invention provides a control system for a variable frequency power supply, the system comprising:

[0033] An SPWM module, for generating an SPWM signal to drive and control the IGBT in the variable frequency power supply in response to the start-up operation of the variable frequency power supply, so as to output a sinusoidal wave voltage;

[0034] The temperature control module is used to obtain the IGBT temperature and the ambient temperature during the operation of the IGBT, determine the IGBT temperature rise according to the IGBT temperature and the ambient temperature, and determine the target carrier ratio according to the IGBT temperature rise;

[0035] The adjustment module is used to adjust the SPWM signal according to the target carrier ratio, and drive the IGBT to be turned on and off according to the adjusted SPWM signal to achieve temperature rise control of the IGBT.

[0036] In order to solve the above problems, one aspect of an embodiment of the present invention provides an electronic device, including: a processor, and a memory storing a program, wherein the program includes instructions, and when the instructions are executed by the processor, the processor executes any of the above-mentioned control methods for variable frequency power supplies.

[0037] In order to solve the above problems, one aspect of an embodiment of the present invention provides a non-transitory machine-readable medium storing computer instructions, where the computer instructions are used to enable a computer to execute any of the above-mentioned control methods for variable frequency power supplies.

[0038] The beneficial effects of the embodiments of the present invention are as follows: by adopting a method of driving and controlling the IGBT in the variable frequency power supply based on the SPWM module in response to the startup operation of the variable frequency power supply to output a sine wave voltage; obtaining the IGBT temperature and the ambient temperature during the operation of the IGBT, determining the IGBT temperature rise according to the IGBT temperature and the ambient temperature, and determining the target carrier ratio according to the IGBT temperature rise; adjusting the SPWM signal according to the target carrier ratio, and driving the IGBT to be turned on and off according to the adjusted SPWM signal to achieve a technical means of controlling the temperature rise of the IGBT, which overcomes the problems in the related art caused by adopting a hard switch pulse width modulation method and setting a fixed temperature The temperature control method with an upper limit on the temperature result in high switching loss of the IGBT and poor IGBT temperature rise control effect, which affects the efficiency and service life of the equipment. The excessive switching loss causes the IGBT to heat up quickly, which in turn affects the operation effect of the equipment. This is based on effective monitoring of the IGBT temperature rise and adjustment of the carrier ratio in the SPWM signal according to the IGBT temperature rise, thereby effectively reducing the switching loss of the IGBT and controlling the temperature rise of the IGBT. This realizes dynamic control of the IGBT temperature rise according to the equipment operation conditions, improves the temperature rise control effect, increases the equipment efficiency and service life, reduces the operating energy consumption, and achieves the technical effect of expanding the application scenarios of variable frequency power supplies.

[0039] The details of one or more embodiments of the invention are set forth in the following drawings and description so that other features, objects, and advantages of the invention are more readily apparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other embodiments can be obtained based on these drawings without creative work.

[0041] Figure 1 It is a main flow chart of a method for controlling a variable frequency power supply according to an embodiment of the present invention.

[0042] Figure 2 It is a main framework schematic diagram of a control system of a variable frequency power supply according to another embodiment of the present invention.

[0043] Figure 3 It is a schematic structural diagram of the electronic device of the present invention. DETAILED DESCRIPTION

[0044] Embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described herein, which are instead provided for a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0045] In order to solve the above problems, an embodiment of the present invention provides a control method for a variable frequency power supply, such as Figure 1 As shown, the control method of the variable frequency power supply mainly includes:

[0046] Step S101 , in response to the start-up of the variable frequency power supply, the SPWM module generates an SPWM signal to drive and control the IGBT in the variable frequency power supply to output a sinusoidal wave voltage.

[0047] Among them, the SPWM (Sinusoidal Pulse Width Modulation) provided in the embodiment of the present invention is a modulation technology that simulates a sine wave output by changing the pulse width. The SPWM technology is used to adjust the pulse width of the output voltage by changing the duty cycle of the modulation wave, and the on and off of the IGBT is driven and controlled based on the SPWM signal to make the pulse width of the output voltage consistent with the envelope of the sine wave, thereby achieving the purpose of converting the DC voltage into a sine wave. Furthermore, by changing the duty cycle of the modulation wave and flexibly adjusting the pulse width of the output voltage, flexible voltage regulation can also be achieved to meet the needs of different applications.

[0048] According to a specific implementation of the embodiment of the present invention, the generation process of the above SPWM signal is as follows:

[0049] (1) Generate the required reference sine wave signal, also called the modulation wave signal, based on a digital signal processor (DSP) or a microcontroller. The modulation wave signal frequency fm and the modulation wave signal amplitude Vref corresponding to the modulation wave signal can be set according to the application requirements; specifically, the modulation wave signal frequency fm is usually equal to the required output AC voltage frequency, but in different applications, the modulation signal frequency may be different, such as when the output voltage is to supply power to the grid, it is usually the grid frequency of 50Hz or 60Hz; such as in a variable frequency drive, the modulation signal frequency can be adjusted according to the speed of the motor; in an audio amplifier, the modulation signal frequency can cover the audio range (20Hz to 20kHz); the modulation wave signal amplitude Vref determines the amplitude of the output voltage, and the modulation signal amplitude can be normalized (for example, between 0 and 1) or an actual voltage value.

[0050] (2) Generate a triangular wave or sawtooth wave carrier signal, where the carrier signal frequency fc and the carrier signal amplitude Vcarrier are set according to the carrier ratio N and the modulation ratio M. Specifically, the carrier signal frequency fc is usually much higher than the modulation wave signal frequency fm. A higher carrier signal frequency can produce an output waveform closer to an ideal sine wave and reduce harmonic distortion. However, a high-frequency carrier signal will increase the switching loss of the power switching device IGBT, thereby reducing the efficiency of the variable frequency power supply. The common carrier signal frequency range is from several kilohertz to tens of kilohertz (for example, 10kHz). The specific selection depends on the specific requirements of the application and the overall design of the system. The carrier signal is usually a triangular wave or a sawtooth wave; the modulation ratio M is defined as the ratio of the modulation wave signal amplitude Vref to the carrier signal amplitude Vcarrier, that is, M = Vref / Vcarrier. The modulation ratio determines the effective value of the output voltage (a higher modulation ratio will produce a higher effective value of the output voltage, but an excessively high modulation ratio will cause distortion of the output waveform). An integer multiple of the carrier ratio is usually selected to ensure that the number of pulses in each cycle is the same, thereby simplifying the control logic and improving the symmetry of the output waveform. Common carrier ratios include N=8, 10, 12, 16, etc. Selecting an appropriate carrier ratio can balance the output waveform quality and system efficiency. The carrier ratio N is the carrier signal frequency fc and the modulation wave signal frequency fm, that is, N=fc / fm. The carrier ratio determines the number of pulses in each cycle (a higher carrier ratio can produce a smoother output waveform, but will increase switching losses; a lower carrier ratio can reduce switching losses, but will reduce the quality of the output waveform).

[0051] (3) Compare the modulation wave signal with the carrier signal. When the value of the modulation wave signal is greater than the value of the carrier signal, a high level is generated (turning on the IGBT); otherwise, a low level is generated (turning off the IGBT). Based on this, a series of pulse signals with different widths can be obtained, namely the SPWM signal.

[0052] (4) The generated SPWM signal is used to drive the IGBT, causing it to alternately turn on and off in each switching cycle, thereby outputting an approximately sinusoidal waveform and realizing the conversion of DC voltage to AC voltage.

[0053] According to another specific implementation of the embodiment of the present invention, it is assumed that a 50Hz sine wave is to be generated, the carrier frequency is 10kHz, and the modulation ratio is 0.8. Then the modulation wave signal frequency fm=50Hz; the modulation wave signal amplitude Vref=0.8×Vdc (assuming that the DC bus voltage is known). The carrier signal frequency fc=10kHz, the carrier signal amplitude Vcarrier=Vdc. The carrier ratio N=fc / fm=10000 / 50=200. In each carrier cycle, the reference sine wave and the carrier signal are compared to generate a high level or low level pulse, that is, an SPWM signal is generated.

[0054] In some of the embodiments, the initial carrier ratio can also be pre-set, and after determining the modulation signal frequency corresponding to the reference sine wave, the carrier signal frequency is determined according to the modulation signal frequency and the initial carrier ratio. The embodiments of the present invention also provide several schemes for determining the initial carrier ratio: (a) Selecting the carrier frequency and the modulation frequency according to the empirical value of the application. For example, in general inverter applications, the carrier frequency is usually selected to be around 10kHz, and the modulation frequency is selected to be 50Hz or 60Hz. (b) Simulating through simulation software (such as MATLAB / Simulink, PSpice, etc.) to analyze the output waveform quality, switching loss and system efficiency under different carrier frequencies and modulation frequencies. Through experimental testing, the system performance under different parameters is actually measured, and the optimal carrier frequency and modulation frequency are selected. (c) Refer to relevant industry standards and specifications to select the recommended carrier frequency and modulation frequency. (d) Comprehensively consider factors such as output waveform quality, system efficiency, filter design, EMI problems, etc., and select the most suitable carrier frequency and modulation frequency.

[0055] In some embodiments, the SPWM signal is a bipolar SPWM signal.

[0056] The characteristic of bipolar SPWM is that the output waveform has two positive and negative levels in each carrier cycle, so that an output waveform closer to an ideal sine wave can be generated, and harmonic distortion can be effectively reduced. By introducing the technology of bipolar three-level control logic, the switching times of the power switching device IGBT can be reduced, thereby reducing switching losses and increasing the service life of the IGBT. According to a specific implementation of an embodiment of the present invention, the bipolar modulation process is to compare the modulation wave signal with the triangular wave or sawtooth wave carrier signal to generate a bipolar SPWM signal (the characteristic of bipolar modulation is that the reference sine wave can change between positive and negative, and the generated SPWM signal is also bipolar). Then, according to the bipolar SPWM signal, a driving signal of the three-level inverter is generated, specifically: when the value of the modulation wave signal is greater than the carrier signal, a positive level (+Vdc / 2) is output; when the value of the modulation wave signal is equal to the carrier signal, a zero level (0) is output; when the value of the modulation wave signal is less than the carrier signal, a negative level (-Vdc / 2) is output.

[0057] Furthermore, according to an embodiment of the present invention, soft switching technology, such as zero voltage switching (ZVS) or zero current switching (ZCS), can be introduced in the pulse width modulation process to reduce the loss of the IGBT during the switching process. The soft switching technology can reduce the voltage or current when the IGBT is switched, thereby reducing the switching loss and improving the efficiency and life of the equipment.

[0058] Step S102 , obtaining the IGBT temperature and the ambient temperature during the operation of the IGBT, determining the IGBT temperature rise according to the IGBT temperature and the ambient temperature, and determining the target carrier ratio according to the IGBT temperature rise.

[0059] Since existing temperature control systems can usually only prevent equipment from overheating by setting a fixed upper temperature limit, and this fixed setting cannot be dynamically adjusted according to the actual operation of the equipment, it may cause the equipment to overheat or consume too much energy. Especially in complex working environments, the temperature requirements of the equipment may vary greatly, and fixed settings are difficult to adapt.

[0060] Since a higher carrier ratio will increase the number of switching times of switching devices such as IGBTs, the switching loss will increase, and then the temperature rise of the IGBT will increase. Through the above settings, when the IGBT temperature rise at the monitoring point is too high or the temperature rise is too fast, the switching loss of the IGBT can be reduced by appropriately reducing the carrier ratio to control the temperature rise of the IGBT.

[0061] Through the above steps, the temperature control system monitors and obtains the IGBT temperature and ambient temperature in real time, determines the IGBT temperature rise, and automatically adjusts the carrier ratio according to the temperature change. This allows the subsequent automatic control system to automatically adjust the equipment's operating parameters (SPWM signal) according to the feedback information (target carrier ratio) of the temperature control system to ensure that the equipment works in the best state, thereby controlling the IGBT's temperature rise, preventing overheating, and improving the equipment's operating efficiency and stability.

[0062] In some of the embodiments, the above-mentioned steps of determining the IGBT temperature rise based on the IGBT temperature and the ambient temperature, and determining the target carrier ratio based on the IGBT temperature rise also include: calculating the difference between the IGBT temperature and the ambient temperature to obtain the IGBT temperature rise; judging whether the IGBT temperature rise exceeds the temperature rise threshold, and if so, determining the carrier ratio reduction ratio based on the ratio of the IGBT temperature rise exceeding the temperature rise threshold, and determining the target carrier ratio based on the current carrier ratio and the carrier ratio reduction ratio.

[0063] By adjusting the carrier ratio, the number of IGBT switches can be dynamically adjusted to control its temperature rise. When the IGBT temperature is high, the carrier ratio can be appropriately reduced to reduce the number of switches, which helps prevent IGBT overheating and extend its service life. Reducing switching losses can also improve the overall efficiency of the system and reduce energy losses. When the temperature is low, the carrier ratio can be increased to improve the output waveform quality. Dynamically adjusting the carrier ratio can enable the system to maintain optimal performance under different load and temperature conditions, improve the reliability and adaptability of the variable frequency power supply, and by timely adjusting the carrier ratio, failures and shutdowns caused by IGBT overheating can be avoided.

[0064] In some embodiments, the above method also includes: obtaining the secondary side current value of the variable frequency power supply, and adjusting the temperature rise threshold according to the secondary side current value; wherein, if the secondary side current value is greater than or equal to the current threshold, the temperature rise threshold is adjusted; if the secondary side current value is less than the current threshold, the temperature rise threshold is adjusted.

[0065] The secondary side current value (in the variable frequency power supply system, the secondary side is usually the inverter output end (i.e. the side connected to the motor or other load)) is an important indicator of the load state in the variable frequency power supply system, which directly reflects the size of the load. By monitoring the secondary side current, the load condition of the system can be effectively judged, thereby determining whether the system is operating under light load or heavy load conditions. When the load is small and the secondary side current is low, it is called a light load state, and the load can be recorded as a light load. When the load is large and the secondary side current is high, it is called a heavy load state, and the load can be recorded as a heavy load.

[0066] Through the above settings, by real-time monitoring of the secondary side current, the load changes can be timely understood, so as to take corresponding control measures. Under light load conditions, the carrier ratio can be appropriately increased to obtain better output waveform quality and improve the efficiency and performance of the system. Under heavy load conditions, the carrier ratio can be reduced to reduce switching losses, control the temperature rise of the IGBT, prevent the equipment from overheating or damage, and improve the reliability and service life of the variable frequency power supply system. At the same time, based on the above steps, the control method provided by the embodiment of the present invention can better adapt to the operating requirements under different working conditions. By combining the secondary side current and IGBT temperature rise information, more accurate thermal management and performance optimization can be achieved, which not only ensures the safety of the variable frequency power supply, but also helps to expand the applicable scenarios of the variable frequency power supply.

[0067] In some of the embodiments, the method further includes: updating the target carrier ratio according to the IGBT temperature rise and the adjusted temperature threshold, and adjusting the SPWM signal according to the updated target carrier ratio.

[0068] After the temperature threshold is adjusted, timely updating and adjusting the carrier ratio and SPWM signal helps to ensure that the device works in the best state, improve device efficiency and provide device adaptability.

[0069] In some of the embodiments, if the IGBT temperature exceeds a temperature threshold or the IGBT temperature rise exceeds a temperature rise threshold, the method further includes: reducing the output power or output current of the variable frequency power supply.

[0070] By real-time monitoring of IGBT temperature and temperature rise, and taking measures to reduce output power or output current when the threshold is exceeded, fault diagnosis and adaptive control of IGBT are realized, thereby effectively protecting the equipment and ensuring the stable operation of the variable frequency power supply system. Based on the above settings, not only the efficiency and reliability of the system are improved, but also the service life of the equipment is extended, and it can better adapt to the operation requirements under different working conditions.

[0071] In some of the embodiments, the step of determining the target carrier ratio according to the IGBT temperature rise further includes: obtaining a mapping table of temperature rise-carrier ratio, and determining the target carrier ratio according to the mapping table and the IGBT temperature rise.

[0072] The target carrier ratio can be adjusted step by step (dynamically), and the optimal target carrier ratio can be quickly determined through a pre-built temperature rise-carrier ratio mapping table to improve control efficiency.

[0073] In some of the embodiments, the method further includes a step of constructing a temperature rise-carrier ratio mapping table: obtaining an upper temperature limit of the IGBT, selecting a plurality of IGBT sample temperatures that do not exceed the upper temperature limit of the IGBT, and determining the corresponding IGBT sample temperature rise; determining a carrier ratio interval according to the maximum switching frequency of the IGBT in the variable frequency power supply, the filter model, and the operating frequency range of the transformer; for any IGBT sample temperature rise, setting a plurality of sample carrier ratios in the carrier ratio interval, adjusting the SPWM signal according to the sample carrier ratio, obtaining the IGBT test temperature rise at the next preset moment, and determining the optimal sample carrier ratio corresponding to the IGBT sample temperature rise according to the IGBT test temperature rise; performing linear fitting processing on a plurality of IGBT sample temperature rises and their corresponding optimal sample carrier ratios, and constructing a temperature rise-carrier ratio mapping table according to the linear fitting processing results.

[0074] In some of the embodiments, the step of constructing the temperature rise-carrier ratio mapping table further includes: determining the upper temperature limit of the IGBT according to the IGBT model, and determining the carrier ratio interval according to the maximum switching frequency of the IGBT in the variable frequency power supply, the filter model, and the operating frequency range of the transformer; simulating the IGBT temperature rise conditions under different carrier ratios within the range of the IGBT temperature upper limit and the carrier ratio interval; and constructing a mapping table of the temperature rise-carrier ratio based on the data corresponding to the simulated carrier ratio and the IGBT temperature rise.

[0075] The upper temperature limit of IGBT refers to the upper temperature limit at which the IGBT can work stably and reliably. It can be determined based on the parameters provided by the manufacturer or based on actual engineering tests.

[0076] The selection of carrier ratio N is related to multiple equipment parameters in the variable frequency power supply system, including IGBT, transformer, filter, etc. Specifically, the switching frequency capability of IGBT is an important factor in selecting the carrier ratio. A higher carrier ratio means a higher switching frequency, which will increase the switching loss of IGBT and lead to an increase in temperature rise. Therefore, it is necessary to determine the appropriate carrier ratio based on the maximum allowable switching frequency of IGBT. It can also be understood that the maximum allowable switching frequency of IGBT determines the upper limit of the carrier signal frequency fc. The design of the transformer needs to consider its operating frequency range. A higher carrier ratio means a higher operating frequency, which may increase the core loss and winding loss. When selecting the carrier ratio, it is necessary to ensure that the transformer can work efficiently within the frequency range and the temperature rise is within the safe range. The design of the filter needs to consider the impact of the carrier ratio on the output waveform quality and EMI. A higher carrier ratio can use smaller filter components, but requires stronger electromagnetic interference (EMI) suppression capability. When selecting the carrier ratio, it is necessary to ensure that the filter can effectively filter out high-order harmonics and meet EMI standards.

[0077] Based on the above two embodiments, two schemes for constructing the temperature rise-carrier ratio are provided. It should be noted that, on the basis of the present invention providing a method for adjusting the carrier ratio according to the temperature rise, thereby reducing the IGBT switching loss and controlling the IGBT temperature rise, the dynamic adjustment of the carrier ratio based on the temperature rise, or the pre-construction of a mapping table to achieve fast optimal adjustment, are all within the protection scope required by the present invention. The specific adjustment method can be selected according to the adaptability to the actual working conditions.

[0078] In some of the embodiments, the IGBT temperature is obtained by a temperature sensor arranged in a heat sink corresponding to the IGBT, and the ambient temperature is obtained by a temperature sensor arranged in a control cabinet of the variable frequency power supply; the above-mentioned step of determining the IGBT temperature rise according to the IGBT temperature and the ambient temperature also includes: obtaining IGBT parameters, and calculating the first temperature rise corresponding to the IGBT according to the IGBT parameters; wherein the IGBT parameters include the thermal resistance value corresponding to the IGBT, the current value flowing through the IGBT, the heat dissipation area and the thermal conductivity; calculating the difference between the IGBT temperature and the ambient temperature to obtain the second temperature rise corresponding to the IGBT; and adding the first temperature rise and the second temperature rise to obtain the IGBT temperature rise.

[0079] Through the multi-point layout of temperature sensors, that is, temperature monitoring adopts a matrix temperature measurement array. The temperature sensors are not only placed in the IGBT heat sink, but also arranged in the control cabinet. The temperature changes of the IGBT and the surrounding environment can be monitored more accurately, thereby improving the accuracy of the IGBT temperature rise calculation, and then based on accurate temperature data, it helps to better protect the IGBT from overheating damage.

[0080] According to a specific implementation of an embodiment of the present invention, the expression for calculating the IGBT temperature rise ΔT is as follows:

[0081]

[0082] in, represents the first temperature rise, (T1-T0) represents the second temperature rise, I represents the current value flowing through the IGBT, R represents the thermal resistance value corresponding to the IGBT (representing the heat conduction resistance from the node to the heat sink inside the IGBT), K is the thermal conductivity, A is the heat dissipation area, T1 is the IGBT temperature (actually the radiator temperature monitored by the temperature sensor installed in the radiator), and T0 is the ambient temperature.

[0083] Based on the above expression, it can be seen that when only the actual temperature and ambient temperature of the IGBT need to be measured, the IGBT temperature rise (i.e. the second temperature rise mentioned above) can also be calculated directly. This is the minimum calculation amount for the IGBT temperature rise and is suitable for scenarios where temperature accuracy and carrier ratio accuracy are not required.

[0084] The first temperature rise mentioned above refers to the temperature rise caused by the heat generated by the current passing through the IGBT. The sum of the first temperature rise and the second temperature rise calculated based on this part improves the accuracy of the final IGBT temperature rise, which is suitable for scenarios with high requirements for accuracy and high requirements for temperature rise control.

[0085] Step S103, adjusting the SPWM signal according to the target carrier ratio, and driving the IGBT to be turned on and off according to the adjusted SPWM signal, so as to achieve temperature rise control of the IGBT.

[0086] In the above step S102, based on monitoring the temperature rise of the IGBT based on the temperature control system and determining the target carrier ratio according to the temperature rise of the IGBT, the SPWM information is adjusted by the automatic control system in combination with the target carrier ratio, and the on and off of the IGBT is driven and controlled based on the adjusted SPWM signal, thereby reducing the switching frequency of the IGBT and the number of switches in each cycle, significantly reducing switching losses, reducing energy losses, and improving the overall efficiency of the variable frequency power supply system.

[0087] Based on step S102 and step 103, the coordinated control effect of the temperature control system and the automatic control system is actually achieved. Compared with the prior art, the technical solution can better coordinate the relationship between temperature control and system operation, thereby achieving more efficient and stable system operation and achieving better temperature rise control effect.

[0088] The control method of the variable frequency power supply provided in the embodiment of the present invention adopts a method of driving and controlling the IGBT in the variable frequency power supply based on the SPWM module in response to the startup operation of the variable frequency power supply to output a sine wave voltage; the IGBT temperature and the ambient temperature are obtained during the operation of the IGBT, the IGBT temperature rise is determined according to the IGBT temperature and the ambient temperature, and the target carrier ratio is determined according to the IGBT temperature rise; the SPWM signal is adjusted according to the target carrier ratio, and the IGBT is driven to be turned on and off according to the adjusted SPWM signal to achieve a technical means of controlling the temperature rise of the IGBT, thereby overcoming the problem in the related art that the pulse width modulation method of hard switching is adopted to control the temperature rise of the IGBT. The temperature control method of setting a fixed temperature upper limit leads to high switching loss of IGBT and poor IGBT temperature rise control effect, affecting the efficiency and service life of the equipment. The excessive switching loss causes the IGBT to heat up rapidly, which in turn affects the operation effect of the equipment. The method is based on effective monitoring of the IGBT temperature rise and adjusting the carrier ratio in the SPWM signal according to the IGBT temperature rise, thereby effectively reducing the switching loss of the IGBT and controlling the temperature rise of the IGBT. The method realizes dynamic control of the IGBT temperature rise according to the equipment operation conditions, improves the temperature rise control effect, improves the equipment efficiency and service life, reduces the operating energy consumption, and achieves the technical effect of expanding the application scenarios of variable frequency power supply.

[0089] Based on the control method of the variable frequency power supply provided in the embodiment of the present invention, the embodiment of the present invention also provides a control system of the variable frequency power supply, which is applied to the output waveform control of the variable frequency power supply and the temperature rise control of the power switching device IGBT, such as Figure 2 As shown, the control system 200 of the variable frequency power supply includes:

[0090] The SPWM module 201 is used to generate an SPWM signal to drive and control the IGBT in the variable frequency power supply in response to the start-up operation of the variable frequency power supply to output a sinusoidal wave voltage.

[0091] Through the above settings, the SPWM technology is used to adjust the pulse width of the output voltage by changing the duty cycle of the modulation wave, and the on and off of the IGBT is driven and controlled based on the SPWM signal, so that the pulse width of the output voltage is consistent with the envelope of the sine wave, and the purpose of converting the DC voltage into a sine wave can be achieved. Furthermore, by changing the duty cycle of the modulation wave, the pulse width of the output voltage can be flexibly adjusted, and flexible voltage regulation can also be achieved to meet the needs of different applications.

[0092] In some embodiments, the SPWM signal is a bipolar SPWM signal. By introducing the bipolar three-level control logic technology, the switching times of the power switch device IGBT can be reduced, thereby reducing the switching loss and increasing the service life of the IGBT.

[0093] The temperature control module 202 is used to obtain the IGBT temperature and the ambient temperature during the operation of the IGBT, determine the IGBT temperature rise according to the IGBT temperature and the ambient temperature, and determine the target carrier ratio according to the IGBT temperature rise.

[0094] Through the above settings, the temperature control system monitors and obtains the IGBT temperature and ambient temperature in real time, determines the IGBT temperature rise, and automatically adjusts the carrier ratio according to the temperature change. This allows the subsequent automatic control system to automatically adjust the equipment's operating parameters (SPWM signal) based on the feedback information (target carrier ratio) of the temperature control system to ensure that the equipment works in the best state, thereby controlling the IGBT's temperature rise, preventing overheating, and improving the equipment's operating efficiency and stability.

[0095] In some of the embodiments, the temperature control module 202 is further used to: calculate the difference between the IGBT temperature and the ambient temperature to obtain the IGBT temperature rise; determine whether the IGBT temperature rise exceeds the temperature rise threshold, and if so, determine the carrier ratio reduction ratio based on the ratio of the IGBT temperature rise exceeding the temperature rise threshold, and determine the target carrier ratio based on the current carrier ratio and the carrier ratio reduction ratio.

[0096] By adjusting the carrier ratio, the number of IGBT switches can be dynamically adjusted to control its temperature rise. When the IGBT temperature is high, the carrier ratio can be appropriately reduced to reduce the number of switches, which helps prevent the IGBT from overheating and prolong its service life. Reducing switching losses can also improve the overall efficiency of the system and reduce energy losses.

[0097] In some of the embodiments, the temperature control module 202 is also used to: obtain the secondary side current value of the variable frequency power supply, and adjust the temperature rise threshold according to the secondary side current value; if the secondary side current value is greater than or equal to the current threshold, the temperature rise threshold is adjusted; if the secondary side current value is less than the current threshold, the temperature rise threshold is adjusted.

[0098] By real-time monitoring of the secondary current, we can timely understand the load changes and take corresponding control measures. Under light load conditions, the carrier ratio can be appropriately increased to obtain better output waveform quality and improve system efficiency and performance.

[0099] In some of the embodiments, the IGBT temperature is obtained by a temperature sensor arranged in a heat sink corresponding to the IGBT, and the ambient temperature is obtained by a temperature sensor arranged in a control cabinet of the variable frequency power supply; the temperature control module 202 is also used to: obtain IGBT parameters, and calculate the first temperature rise corresponding to the IGBT according to the IGBT parameters; wherein the IGBT parameters include the thermal resistance value corresponding to the IGBT, the current value flowing through the IGBT, the heat dissipation area and the thermal conductivity; calculate the difference between the IGBT temperature and the ambient temperature to obtain the second temperature rise corresponding to the IGBT; and add the first temperature rise and the second temperature rise to obtain the IGBT temperature rise.

[0100] Through the above settings, the temperature sensors based on the multi-point layout can more accurately monitor the temperature changes of the IGBT and the surrounding environment, thereby improving the accuracy of the IGBT temperature rise calculation, and then based on the accurate temperature data, it helps to better protect the IGBT from overheating damage.

[0101] The adjustment module 203 is used to adjust the SPWM signal according to the target carrier ratio, and drive the IGBT to be turned on and off according to the adjusted SPWM signal, so as to achieve temperature rise control of the IGBT.

[0102] The automatic control system adjusts the SPWM information in combination with the target carrier ratio, and drives and controls the on and off of the IGBT based on the adjusted SPWM signal, thereby reducing the switching frequency of the IGBT and the number of switches in each cycle, significantly reducing switching losses, reducing energy losses, and improving the overall efficiency of the variable frequency power supply system.

[0103] In some embodiments, after the temperature threshold is adjusted, the adjustment module 203 is further used to: update the target carrier ratio according to the IGBT temperature rise and the adjusted temperature threshold, and adjust the SPWM signal according to the updated target carrier ratio. After the temperature threshold is adjusted, timely updating and adjusting the carrier ratio and the SPWM signal helps to ensure that the device works in the best state, improve the efficiency of the device and provide device adaptability.

[0104] In some of the embodiments, if the IGBT temperature exceeds a temperature threshold or the IGBT temperature rise exceeds a temperature rise threshold, the adjustment module 203 is further configured to reduce the output power or output current of the variable frequency power supply.

[0105] By real-time monitoring of IGBT temperature and temperature rise, and taking measures to reduce output power or output current when the threshold is exceeded, fault diagnosis and adaptive control of IGBT are realized, thereby effectively protecting the equipment and ensuring the stable operation of the variable frequency power supply system. Based on the above settings, not only the efficiency and reliability of the system are improved, but also the service life of the equipment is extended, and it can better adapt to the operation requirements under different working conditions.

[0106] The control system of the above-mentioned variable frequency power supply provided by the embodiment of the present invention is used to generate an SPWM signal to drive and control the IGBT in the variable frequency power supply in response to the startup operation of the variable frequency power supply through an SPWM module to output a sine wave voltage; a temperature control module is used to obtain the IGBT temperature and the ambient temperature during the operation of the IGBT, determine the IGBT temperature rise according to the IGBT temperature and the ambient temperature, and determine the target carrier ratio according to the IGBT temperature rise; an adjustment module is used to adjust the SPWM signal according to the target carrier ratio, and drive the IGBT to be turned on and off according to the adjusted SPWM signal to achieve temperature rise control of the IGBT, and achieve effective monitoring of the IGBT temperature rise and adjust the carrier ratio in the SPWM signal according to the IGBT temperature rise, thereby effectively reducing the switching loss of the IGBT, thereby controlling the temperature rise of the IGBT, and achieving dynamic control of the IGBT temperature rise according to the equipment operation status, improving the temperature rise control effect, improving the equipment efficiency and service life, reducing the operating energy consumption, and achieving the technical effect of expanding the application scenarios of the variable frequency power supply.

[0107] An embodiment of the present invention further provides a non-transitory machine-readable medium storing a computer program, wherein the computer program, when executed by a processor of a computer, is used to cause the computer to execute the method of the embodiment of the present invention.

[0108] The embodiment of the present invention further provides a computer program product, including a computer program, wherein the computer program is used to make the computer perform the method of the embodiment of the present invention when executed by a processor of the computer. The computer program product should be understood as a software product that mainly implements the above method of the present application through a computer program.

[0109] An embodiment of the present invention further provides an electronic device, comprising: at least one processor; and a memory in communication with the at least one processor. The memory stores a computer program executable by the at least one processor, and when the computer program is executed by the at least one processor, the electronic device executes the method of the embodiment of the present invention.

[0110] refer to Figure 3 , a block diagram of an electronic device that can be used as a server or client of an embodiment of the present invention will now be described, which is an example of a hardware device that can be applied to various aspects of the present invention. The electronic device is intended to represent various forms of digital electronic computer devices, such as laptop computers, desktop computers, workbenches, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0111] like Figure 3 As shown, the electronic device includes a computing unit 301, which can perform various appropriate actions and processes according to a computer program stored in a read-only memory (ROM) 302 or a computer program loaded from a storage unit 308 into a random access memory (RAM) 303. In the RAM 303, various programs and data required for the operation of the electronic device can also be stored. The computing unit 301, the ROM 302, and the RAM 303 are connected to each other via a bus 304. An input / output (I / O) interface 305 is also connected to the bus 304.

[0112] Multiple components in the electronic device are connected to the I / O interface 305, including: an input unit 306, an output unit 307, a storage unit 308, and a communication unit 309. The input unit 306 can be any type of device that can input information to the electronic device, and the input unit 306 can receive input digital or character information, and generate key signal input related to user settings and / or function control of the electronic device. The output unit 307 can be any type of device that can present information, and can include but is not limited to a display, a speaker, a video / audio output terminal, a vibrator, and / or a printer. The storage unit 308 can include but is not limited to a disk, an optical disk. The communication unit 309 allows the electronic device to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks, and can include but is not limited to a modem, a network card, an infrared communication device, and / or a wireless communication transceiver, such as a Bluetooth device, a WiFi device, a WiMax device, a cellular communication device, and / or the like.

[0113] The computing unit 301 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the computing unit 301 include, but are not limited to, a CPU, a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing units, various computing units running machine learning model algorithms, digital signal processors (DSPs), and any appropriate processors, controllers, microcontrollers, etc. The computing unit 301 performs the various methods and processes described above. For example, in some embodiments, the method embodiments of the present invention may be implemented as a computer program, which is tangibly contained in a machine-readable medium, such as a storage unit 308. In some embodiments, part or all of the computer program may be loaded and / or installed on an electronic device via a ROM 302 and / or a communication unit 309. In some embodiments, the computing unit 301 may be configured to perform the above-described method in any other appropriate manner (e.g., by means of firmware).

[0114] The computer programs for implementing the methods of the embodiments of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when the computer programs are executed by the processor or controller, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer programs may be executed entirely on the machine, partially on the machine, partially on the machine as a stand-alone software package and partially on a remote machine, or entirely on a remote machine or server.

[0115] In the context of an embodiment of the present invention, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or equipment. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable signal medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, or infrared systems, devices, or equipment, or any suitable combination of the foregoing. More specific examples of machine-readable storage media may include electrical connections based on one or more lines, portable computer disks, hard disks, random access memories (RAM), read-only memories (ROM), erasable programmable read-only memories (EPROM or flash memory), optical fibers, portable compact disk read-only memories (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0116] It should be noted that the term "including" and its variations used in the embodiments of the present invention are open inclusions, that is, "including but not limited to". The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments". The modifications of "one" and "multiple" mentioned in the embodiments of the present invention are illustrative rather than restrictive. Those skilled in the art should understand that unless the context clearly indicates otherwise, it should be understood as "one or more".

[0117] The data involved in the embodiments of the present invention (including but not limited to data used for analysis, data stored, data displayed, etc.) are all data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant laws, regulations and standards of relevant countries and regions, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0118] The various steps described in the method implementation methods provided in the embodiments of the present invention may be performed in different orders and / or in parallel. In addition, the method implementation methods may include additional steps and / or omit the steps shown. The scope of protection of the present invention is not limited in this respect.

[0119] The term "embodiment" in this specification refers to specific features, structures or characteristics described in conjunction with the embodiment that can be included in at least one embodiment of the present invention. The appearance of this phrase in various places in the specification does not necessarily mean the same embodiment, nor does it mean that it is mutually exclusive with other embodiments and is independent or optional. The various embodiments in this specification are described in a related manner, and the same or similar parts between the various embodiments refer to each other. In particular, for the device, equipment, and system embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts refer to the partial description of the method embodiment.

[0120] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of protection. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the attached claims.

Claims

1. A method for controlling a variable frequency power supply, characterized in that: include: In response to the start-up operation of the variable frequency power supply, the SPWM module generates an SPWM signal to drive and control the IGBT in the variable frequency power supply to output a sinusoidal wave voltage; Acquiring an IGBT temperature and an ambient temperature during operation of the IGBT, determining an IGBT temperature rise according to the IGBT temperature and the ambient temperature, and determining a target carrier ratio according to the IGBT temperature rise; The SPWM signal is adjusted according to the target carrier ratio, and the IGBT is driven to be turned on and off according to the adjusted SPWM signal, so as to achieve temperature rise control of the IGBT.

2. The method according to claim 1, characterized in that The step of determining the IGBT temperature rise according to the IGBT temperature and the ambient temperature, and determining the target carrier ratio according to the IGBT temperature rise also includes: Calculating the difference between the IGBT temperature and the ambient temperature to obtain the IGBT temperature rise; Determine whether the IGBT temperature rise exceeds the temperature rise threshold. If so, determine the carrier ratio reduction ratio based on the ratio of the IGBT temperature rise exceeding the temperature rise threshold, and determine the target carrier ratio based on the current carrier ratio and the carrier ratio reduction ratio.

3. The method according to claim 2, characterized in that The method further comprises: Obtain the secondary side current value of the variable frequency power supply, and adjust the temperature rise threshold according to the secondary side current value; wherein, if the secondary side current value is greater than or equal to the current threshold, lower the temperature rise threshold; if the secondary side current value is less than the current threshold, increase the temperature rise threshold.

4. The method according to claim 3, characterized in that: The method further comprises: The target carrier ratio is updated according to the IGBT temperature rise and the adjusted temperature threshold, and the SPWM signal is adjusted according to the updated target carrier ratio.

5. The method according to claim 2, characterized in that: If the IGBT temperature exceeds a temperature threshold or the IGBT temperature rise exceeds the temperature rise threshold, the method further includes: reducing an output power or an output current of the variable frequency power supply.

6. The method according to claim 1, characterized in that The step of determining the target carrier ratio according to the IGBT temperature rise further includes: A mapping table of temperature rise-carrier ratio is obtained, and a target carrier ratio is determined according to the mapping table and the IGBT temperature rise.

7. The method according to claim 6, characterized in that The method further comprises the step of constructing a mapping table of temperature rise-carrier ratio: Obtaining an upper temperature limit of the IGBT, selecting a plurality of IGBT sample temperatures that do not exceed the upper temperature limit of the IGBT, and determining a corresponding temperature rise of the IGBT samples; Determine the carrier ratio interval according to the maximum switching frequency of the IGBT in the variable frequency power supply, the filter model, and the operating frequency range of the transformer; For any of the IGBT sample temperature rises, a plurality of sample carrier ratios are respectively set within the carrier ratio interval, and the SPWM signal is adjusted according to the sample carrier ratios to obtain the IGBT test temperature rise at the next preset moment, and the optimal sample carrier ratio corresponding to the IGBT sample temperature rise is determined according to the IGBT test temperature rise; A linear fitting process is performed on the temperature rises of the multiple IGBT samples and their corresponding optimal sample carrier ratios, and a mapping table of temperature rise-carrier ratio is constructed according to the linear fitting process results.

8. The method according to claim 1, characterized in that The IGBT temperature is obtained by a temperature sensor arranged in a heat sink corresponding to the IGBT, and the ambient temperature is obtained by a temperature sensor arranged in a control cabinet of the variable frequency power supply; The step of determining the IGBT temperature rise according to the IGBT temperature and the ambient temperature also includes: Obtaining IGBT parameters, and calculating a first temperature rise corresponding to the IGBT according to the IGBT parameters; wherein the IGBT parameters include a thermal resistance value corresponding to the IGBT, a current value flowing through the IGBT, a heat dissipation area, and a thermal conductivity; Calculating the difference between the IGBT temperature and the ambient temperature to obtain a second temperature rise corresponding to the IGBT; The first temperature rise and the second temperature rise are added to obtain the IGBT temperature rise.

9. The method according to claim 1, characterized in that: The SPWM signal is a bipolar SPWM signal.

10. A control system for a variable frequency power supply, characterized in that: The system comprises: An SPWM module, for generating an SPWM signal to drive and control the IGBT in the variable frequency power supply in response to the start-up operation of the variable frequency power supply, so as to output a sinusoidal wave voltage; a temperature control module, used for obtaining the IGBT temperature and the ambient temperature during the operation of the IGBT, determining the IGBT temperature rise according to the IGBT temperature and the ambient temperature, and determining the target carrier ratio according to the IGBT temperature rise; The adjustment module is used to adjust the SPWM signal according to the target carrier ratio, and drive the IGBT to be turned on and off according to the adjusted SPWM signal, so as to achieve temperature rise control of the IGBT.

11. An electronic device, comprising: A processor, and a memory storing a program, wherein the program comprises instructions, which, when executed by the processor, cause the processor to perform the method according to any one of claims 1 to 9.

12. A non-transitory machine-readable medium storing computer instructions, characterized in that: The computer instructions are used to cause the computer to execute the method according to any one of claims 1-9.

Images