Single three-phase switching control method, system and electric heating device

Abstract

The application discloses a single three-phase switching control method and system and an electric heating device, relates to the technical field of three-phase control, and the single three-phase switching control method comprises the following steps: in response to power supply work, acquiring a power supply output parameter, judging a result according to the power supply output parameter and a parameter threshold output phase, and adjusting a frequency conversion parameter based on the phase judgment result to control single three-phase working mode switching. The application has the beneficial effects that: the control logic can be dynamically adjusted according to actual needs without relying on the hardware structure, mechanical delay is avoided, and the real-time performance and reliability of the single three-phase switching control are improved.

Description

Technical Field

[0001] This application relates to the field of three-phase control technology, and in particular to single-phase and three-phase switching control methods, systems and electric heating equipment. Background Technology

[0002] Existing IH products (electromagnetic heating products) may stop operating or cause damage to circuit components such as IGBTs (Insulated Gate Bipolar Transistors) or fuses due to abnormal overcurrent correction when there is a phase loss or voltage imbalance. This cannot effectively protect the product, causing losses to users. Furthermore, the product stops operating or reduces its operating efficiency in the event of a phase loss, affecting its performance.

[0003] The patent "Three-Phase and Single-Phase Output Circuit of Variable Frequency Power Supply", publication number: CN104767395A, publication date: July 8, 2015, specifically discloses a circuit including: an input circuit, a soft-start circuit, a rectifier and filter circuit, a three-phase full-bridge inverter circuit, an isolation transformer and filter circuit, a three-phase to single-phase switching control circuit, a three-phase output circuit, and a single-phase output circuit. The input circuit, soft-start circuit, and rectifier and filter circuit are connected sequentially. The rectifier and filter circuit is connected to the three-phase full-bridge inverter circuit, which is also connected to the isolation transformer and filter circuit. The isolation transformer and filter circuit is connected to the three-phase output circuit and the single-phase output circuit respectively through the three-phase to single-phase switching control circuit. This solution relies on hardware control, and its static control logic and mechanical delay are difficult to meet the requirements of real-time performance and reliability.

[0004] The patent, "An IH Driving Circuit and an IH Heating Circuit and Rice Cooker Using the Same," publication number CN211481490U, published on January 16, 2020, specifically discloses a circuit including a rectifier module, an energy storage module, an AC status detection module, a main control module, a first switch branch, and a second switch branch. The rectifier module is electrically connected to an external AC power supply, the energy storage module, and the IH working module. The detection terminal of the AC status detection module can be electrically connected to the external AC power supply. The main control module is electrically connected to the output terminal of the AC status detection module and the control terminal of the external IH working module. The first switch branch is electrically connected to one pole of the external AC power supply and the first terminal of the energy storage module. The second switch branch is electrically connected to the energy storage module and the other pole of the external AC power supply. The main control module is electrically connected to the first switch branch and the second switch branch. When the first switch branch and the second switch branch are connected, they can form a power-on circuit with the energy storage module. This solution uses an energy storage module to divide the voltage to reduce the impact of the instantaneous voltage on the IGBT components in the IH working module during startup. However, it will still cause a decrease in operating efficiency when the power supply phase is missing, and it still relies on hardware control. Summary of the Invention

[0005] This application addresses the problem that static control logic and mechanical delays in existing single-phase and three-phase switching control technologies cannot meet real-time performance and reliability requirements. It provides a single-phase and three-phase switching control method, system, and electric heating equipment. The method detects phase loss by comparing power output parameters with parameter thresholds, and uses program control to output frequency conversion parameters adapted to single-phase or three-phase based on the phase judgment result, thereby realizing the switching between single-phase and three-phase operating modes. It does not rely on hardware structure, and the control logic can be dynamically adjusted according to actual needs, avoiding mechanical delays and improving the real-time performance and reliability of single-phase and three-phase switching control.

[0006] To achieve the above technical objectives, this application provides a technical solution: a single-phase to three-phase switching control method applied to a frequency converter system, comprising the following steps: in response to power supply operation, acquiring power supply output parameters, outputting phase judgment results based on the power supply output parameters and parameter thresholds, and adjusting frequency converter parameters based on the phase judgment results to control the switching of single-phase to three-phase operating modes.

[0007] Furthermore, the step of outputting the phase judgment result based on the power supply output parameters and parameter thresholds includes: outputting a real-time sine wave based on the three-phase AC waveform, and outputting the phase judgment result based on the comparison result between the real-time sine wave and the three-phase waveform thresholds.

[0008] Furthermore, the parameter thresholds include at least a first parameter threshold for distinguishing between a three-phase state and a state with one phase missing, and a second parameter threshold for distinguishing between a state with one phase missing and a state with two phases missing.

[0009] Furthermore, the step of adjusting the frequency converter parameters based on the phase judgment result to control the switching between single-phase and three-phase operating modes includes: matching the target operating mode based on the phase judgment result, and adjusting the frequency converter parameters according to the matching situation between the target operating mode and the current operating mode to control the switching between single-phase and three-phase operating modes.

[0010] Furthermore, the step of adjusting the frequency converter parameters to control the switching between single-phase and three-phase operating modes based on the matching of the target operating mode and the current operating mode includes: if the target operating mode is a three-phase operating mode and the current operating mode is a single-phase operating mode, then performing phase synchronization power cut-off and adjusting the frequency converter parameters to adapt to the three-phase operating mode; if the target operating mode is a single-phase operating mode and the current operating mode is a three-phase operating mode, then performing phase stripping power reduction and adjusting the frequency converter parameters to adapt to the single-phase operating mode.

[0011] Another technical solution provided in this application is a single-phase to three-phase switching control system for implementing the method described above, comprising: a power output acquisition module for acquiring power output parameters; a phase detection module for outputting phase judgment results based on the power output parameters and parameter thresholds; and a control module for adjusting frequency conversion parameters based on the phase judgment results to perform single-phase to three-phase working mode switching.

[0012] Furthermore, the power output acquisition module includes a voltage AD detection module for acquiring the first power output parameters and a rectification detection module for acquiring the second power output parameters.

[0013] Furthermore, the control module obtains the three-phase balance degree based on the first power output parameters and the second power output parameters, outputs the balance judgment result based on the balance degree threshold and the three-phase balance degree, and adjusts the frequency conversion parameters based on the balance judgment result and the phase judgment result to perform single-phase and three-phase working mode switching.

[0014] Furthermore, it also includes an overvoltage protection module connected to the phase detection module and the power output acquisition module.

[0015] Another technical solution provided in this application is an electric heating device, comprising: a heating module for performing heating, a heating drive module for controlling heating power, and a single-phase / three-phase switching control system, wherein the heating module is connected to the heating drive module, and the heating drive module is connected to the single-phase / three-phase switching control system.

[0016] The beneficial effects of this application are as follows: 1. By comparing the power supply output parameters with the parameter thresholds, it can be determined in real time whether the power supply is single-phase or three-phase, and the frequency conversion parameters can be adjusted according to the phase judgment results to adapt to the current power supply output state, thereby improving the dynamic adaptability of the power supply output. The single-phase or three-phase working mode switching of the system under different power supply output states can be realized without complex switching circuits, thereby reducing hardware costs and failure rates and improving system stability.

[0017] 2. The balance of the three-phase input is obtained based on the three-phase fluctuations before and after rectification. For example, it is first determined whether the ratio of the peak-to-peak ripple of the rectified DC voltage to the average DC voltage is greater than the preset rectification fluctuation threshold. Then, it is further determined whether there is a three-phase imbalance based on whether the negative sequence component detection on the AC side exceeds the preset negative sequence ratio and whether the harmonic distortion rate exceeds the preset distortion rate. When the balance judgment result is unbalanced, the working mode is switched to single-phase working mode to improve system stability. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating the three-phase switching control method of this application.

[0019] Figure 2 This is a schematic diagram of the structure of the electric heating device of this application. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description of this application is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely one preferred embodiment of this application and are only used to explain this application. They do not limit the scope of protection of this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] like Figure 1 As shown in the first embodiment of this application, a single-phase / three-phase switching control method is applied to a frequency converter system and includes the following steps: In response to power supply operation, the system acquires power supply output parameters, outputs phase judgment results based on power supply output parameters and parameter thresholds, and adjusts frequency converter parameters based on phase judgment results to control the switching between single-phase and three-phase operating modes.

[0022] In this embodiment, the power supply is determined in real time whether it is single-phase or three-phase by comparing the power supply output parameters with the parameter thresholds. The frequency conversion parameters are adjusted according to the phase determination results to adapt to the current power supply output state, thereby improving the dynamic adaptability of the power supply output. The system can switch between single-phase and three-phase working modes under different power supply output states without the need for complex switching circuits, reducing hardware costs and failure rates, and improving system stability.

[0023] In this embodiment, the power supply output parameters include at least one of voltage, current, or AC waveform. Correspondingly, the parameter thresholds include at least one of voltage threshold, current threshold, or waveform threshold.

[0024] In some cases, power supply output parameters include three-phase voltage, and parameter thresholds include three-phase voltage thresholds. In this case, the output phase determination result based on the power supply output parameters and parameter thresholds includes: The phase judgment result is output based on the comparison results of the three-phase voltage and the three-phase voltage threshold.

[0025] The voltage threshold can be obtained from the voltage data under three-phase conditions and / or the voltage data under a phase-loss condition. The voltage threshold can be a threshold range or the minimum / maximum value under the current condition. If the voltage threshold is obtained from the voltage data under three-phase conditions, then when all phase voltages in the real-time three-phase voltage meet the three-phase voltage threshold (when the three-phase voltage threshold is within the threshold range, the real-time three-phase voltage falls within the threshold range; when the three-phase voltage threshold is the minimum voltage value, the real-time three-phase voltage is greater than or equal to the minimum voltage value), the phase judgment result is no phase loss. When any phase voltage in the real-time three-phase voltage does not meet the three-phase voltage threshold, the phase judgment result is a phase loss. If the three-phase voltage threshold is obtained from the voltage data under a phase-loss condition, then when any phase voltage in the real-time three-phase voltage data meets the three-phase voltage threshold (when the three-phase voltage threshold is within the threshold range, the real-time three-phase voltage falls within the threshold range; when the three-phase voltage threshold is the maximum voltage value, the real-time three-phase voltage is less than or equal to the maximum voltage value), the phase judgment result is a phase loss. When none of the phase voltages in the real-time three-phase voltage meet the three-phase voltage threshold, the phase judgment result is no phase loss.

[0026] Similarly, when the power supply output parameters include three-phase current, the parameter thresholds include the three-phase current thresholds. In this case, the output phase determination result based on the power supply output parameters and parameter thresholds includes: The phase judgment result is output based on the comparison results of the three-phase current and the three-phase current threshold.

[0027] The current threshold can be obtained from the current data under three-phase conditions and / or the current data under a phase-loss condition. The three-phase current threshold can be a threshold range or the minimum / maximum value under the current condition. If the three-phase current threshold is obtained from the current data under three-phase conditions, then when all phase currents in the real-time three-phase current meet the three-phase current threshold (when the three-phase current threshold is within the threshold range, the real-time three-phase current falls within the threshold range; when the three-phase current threshold is the minimum current value, the real-time three-phase current is greater than or equal to the minimum current value), the phase judgment result is no phase loss. When any phase current in the real-time three-phase current does not meet the three-phase current threshold, the phase judgment result is a phase loss. If the three-phase current threshold is obtained from the current data under a phase-loss condition, then when any phase current in the real-time three-phase current data meets the three-phase current threshold (when the three-phase current threshold is within the threshold range, the real-time three-phase current falls within the threshold range; when the three-phase current threshold is the maximum current value, the real-time three-phase current is less than or equal to the maximum current value), the phase judgment result is a phase loss. When none of the phase currents in the real-time three-phase current meet the three-phase current threshold, the phase judgment result is no phase loss.

[0028] In other cases, the power supply output parameters include three-phase AC waveforms, and the parameter thresholds include three-phase waveform thresholds. In these cases, the output phase determination result based on the power supply output parameters and parameter thresholds includes: The real-time sine wave is output based on the three-phase AC waveform, and the phase judgment result is output based on the comparison result between the real-time sine wave and the three-phase waveform threshold.

[0029] The three-phase waveform threshold can be obtained from sinusoidal waveform data under three-phase conditions and / or sinusoidal waveform data under phase loss conditions. The three-phase waveform threshold can be a threshold range or the minimum / maximum value under the current conditions. If the three-phase waveform threshold is obtained from the sinusoidal waveform data under three-phase conditions, then when the real-time sinusoidal waveform meets the three-phase waveform threshold, the phase judgment result is no phase loss; when the real-time sinusoidal waveform does not meet the three-phase waveform threshold, the phase judgment result is a phase loss. If the three-phase waveform threshold is obtained from the sinusoidal waveform data under phase loss conditions, then when the real-time sinusoidal waveform meets the three-phase waveform threshold, the phase judgment result is a phase loss; when the real-time sinusoidal waveform does not meet the three-phase waveform threshold, the phase judgment result is no phase loss.

[0030] In this embodiment, the parameter thresholds include at least a first parameter threshold that distinguishes between a three-phase state and a state with one phase missing, and a second parameter threshold that distinguishes between a state with one phase missing and a state with two phases missing.

[0031] Correspondingly, when the parameter threshold is a three-phase voltage threshold, it includes at least a first three-phase voltage threshold and a second three-phase voltage threshold; when the parameter threshold is a three-phase current threshold, it includes at least a first three-phase current threshold and a second three-phase current threshold; when the parameter threshold is a three-phase waveform threshold, it includes at least a first three-phase waveform threshold and a second three-phase waveform threshold.

[0032] The first and second parameter thresholds are obtained based on voltage / current / sine wave data under three-phase, one-phase-missing, and two-phase-missing states. For example, a first three-phase voltage threshold is constructed by obtaining the voltage range under the three-phase state voltage data, and a second three-phase voltage threshold is constructed by obtaining the voltage range under the one-phase-missing state voltage data. States that do not meet either the first or second three-phase voltage thresholds are classified as two-phase-missing states. It can be understood that a three-phase state means all three phases of the three-phase power supply are normal, a one-phase-missing state means any one phase of the three-phase power supply is abnormal, and a two-phase-missing state means any two phases of the three-phase power supply are abnormal. In this embodiment, the situation where all three phases of the three-phase power supply are abnormal is included in the two-phase-missing state consideration. In other embodiments, any combination of three-phase voltage, three-phase current, and three-phase AC waveforms can be collected simultaneously; in this case, the parameter thresholds are combinations of the corresponding three-phase voltage threshold, three-phase current threshold, and three-phase waveform thresholds.

[0033] Specifically, the phase judgment result output based on the comparison between the real-time sine waveform and the waveform threshold includes: When the real-time sinusoidal waveform meets the threshold of the first three-phase waveform, the phase judgment result is that there is no missing phase; When the real-time sinusoidal waveform meets the threshold of the second and third phase waveforms, the phase judgment result is that one phase is missing. When the real-time sinusoidal waveform does not meet the threshold values ​​for the first three-phase waveform and the second three-phase waveform, the phase judgment result is that two phases are missing.

[0034] Furthermore, the frequency conversion parameters are adjusted based on the phase judgment results to control the switching of the frequency conversion system between single-phase and three-phase operating modes.

[0035] In this embodiment, adjusting the frequency converter parameters based on the phase judgment result to control the switching between single-phase and three-phase operating modes includes: matching the target operating mode based on the phase judgment result, and adjusting the frequency converter parameters according to the matching situation between the target operating mode and the current operating mode to control the switching between single-phase and three-phase operating modes.

[0036] The operating modes include at least single-phase and three-phase operating modes. Specifically, the target operating mode matched based on the phase determination result includes: If the phase judgment result is that no phase is missing, then the target operating mode is three-phase operating mode; If the phase determination result is that one phase is missing, then the target operating mode is single-phase operating mode.

[0037] Adjusting inverter parameters based on the matching between the target operating mode and the current operating mode to control the switching between single-phase and three-phase operating modes includes: If the target operating mode is three-phase operating mode and the current operating mode is single-phase operating mode, then phase synchronization power cut-off will be performed, and the frequency converter parameters will be adjusted to adapt to the three-phase operating mode. If the target operating mode is single-phase and the current operating mode is three-phase, then phase stripping and energy reduction are performed, and the frequency converter parameters are adjusted to adapt to the single-phase operating mode.

[0038] In this embodiment, phase synchronization power cut-off means stopping the system power output and performing phase synchronization; phase stripping power reduction means suspending part of the system power output and selectively stripping two phases of power supply. When the target operating mode is three-phase operating mode and the current operating mode is single-phase operating mode, if the switch is made directly without stopping the output, the newly connected phase may cause serious unbalanced current or circulating current due to lack of synchronization, damaging the equipment or triggering the protection device. Therefore, the power output in single-phase operating mode is stopped first, and then the frequency converter parameters are adjusted to switch to three-phase operating mode until the phases are aligned before power supply is restored. When the target operating mode is single-phase operating mode and the current operating mode is three-phase operating mode, only two phases of power output need to be suspended. For example, when phase A is missing, the power supply to phases A and B is shut off, and only phase C is retained as the main power supply channel, thereby maintaining system power supply.

[0039] In some cases, adjusting the inverter parameters based on the phase judgment result to control the switching between single-phase and three-phase operating modes also includes: if the phase judgment result is that two phases are missing, performing a power outage shutdown action.

[0040] In other cases, parameter thresholds also include single-phase parameter thresholds and three-phase parameter thresholds. Single-phase parameter thresholds include any one or a combination of single-phase voltage thresholds, single-phase current thresholds, or single-phase waveform thresholds. Three-phase parameter thresholds include any one or a combination of three-phase voltage thresholds, three-phase current thresholds, or three-phase waveform thresholds. In this case, the output phase determination result based on the power supply output parameters and parameter thresholds also includes: If the power supply output parameters meet the single-phase parameter threshold, the phase judgment result is single-phase. If the power supply output parameters do not meet the single-phase parameter threshold, the phase judgment result is output based on the power supply output parameters and the three-phase parameter threshold.

[0041] The single-phase parameter thresholds represent the normal voltage, current, or AC waveform of a single-phase power supply. First, it determines whether the current power supply is single-phase or three-phase to accommodate different power supply connections. When the phase determination result is single-phase, the frequency converter parameters are adjusted to put the frequency converter system into single-phase operation mode. If the power supply output parameters do not meet the single-phase parameter thresholds, the three-phase parameter thresholds are further used to determine if there is a phase loss problem. The phase determination result under three-phase conditions is output to adjust the corresponding frequency converter parameters.

[0042] In some cases, the determination of whether a power source is single-phase or three-phase is performed first, followed by phase determination. For example, the power source connection can be used as the trigger point for power type determination, while the power source operation can be used as the trigger point for phase determination. Power type determination is only triggered when the power source is reconnected. While the power source is not replaced, phase determination is performed based solely on the result of the previous power type determination. This eliminates the need for phase determination if the power source was previously determined to be single-phase, thus reducing redundancy.

[0043] In other embodiments, the single-phase / three-phase switching control method further includes: The system acquires the first power supply output parameters before rectification and the second power supply output parameters after rectification. It calculates the three-phase balance based on the first and second power supply output parameters, outputs the balance judgment result based on the three-phase balance and the balance threshold, and adjusts the frequency converter parameters based on the balance judgment result and the phase judgment result to perform single and three-phase working mode switching.

[0044] In this embodiment, the balance of the three-phase input is obtained based on the three-phase fluctuations before and after rectification. For example, it is first determined whether the ratio of the peak-to-peak ripple of the rectified DC voltage to the average DC voltage is greater than a preset rectification fluctuation threshold. Then, it is further determined whether the negative sequence component on the AC side exceeds a preset negative sequence ratio and whether the harmonic distortion rate exceeds a preset distortion rate to further determine whether there is a three-phase imbalance. When the balance determination result is unbalanced, the operating mode is switched to single-phase operating mode to improve system stability. Of course, in other cases, other methods can also be used to calculate the three-phase balance.

[0045] As a second embodiment of this application, the single-phase / three-phase switching control system includes: Power output acquisition module, used to acquire power output parameters; The phase detection module is used to output phase judgment results based on power supply output parameters and parameter thresholds; The control module is used to adjust the frequency converter parameters based on the phase judgment result to perform single-phase and three-phase working mode switching.

[0046] In this embodiment, the power output acquisition module acquires one or a combination of power supply voltage, power supply current, and AC power waveform. The phase detection module outputs different phase judgment results based on the comparison between the power output parameters acquired by the power output acquisition module and parameter thresholds. High-level, square-wave, and low-level trigger control modules adjust different frequency conversion parameters to switch between single-phase and three-phase operating modes.

[0047] The power output acquisition module is connected to the power supply, the phase detection module is connected to both the power output module and the control module, and the control module is connected to the frequency converter system. The power output acquisition module includes at least three voltage AD detection modules corresponding to the three-phase power. These voltage AD detection modules are connected to both the power supply and the phase detection module to ensure the accuracy of the three-phase power parameter acquisition. In other cases, the control module can also directly use the control chip of the frequency converter system itself to improve integration.

[0048] In other cases, the single-phase / three-phase switching control module also includes a rectifier module connected to the power supply. In this case, the power output acquisition module also includes a rectifier detection module connected to both the rectifier module and the control module.

[0049] The rectifier module converts AC power to DC power, and the rectifier detection module collects the power output parameters after rectification. At this time, the power output parameters include at least the first power output parameters before rectification and the first power output parameters after rectification. The voltage AD detection module collects the first power output parameters, the rectifier detection module collects the second power output parameters, and the voltage AD detection module is also connected to the control module.

[0050] The control module obtains the three-phase balance based on the first power supply output parameters and the second power supply output parameters, outputs the balance judgment result based on the balance threshold and the three-phase balance, and adjusts the frequency conversion parameters based on the balance judgment result and the phase judgment result to perform single and three-phase working mode switching.

[0051] In this embodiment, the single-phase and three-phase switching control module further includes an overvoltage protection module connected to the phase detection module and the power output acquisition module.

[0052] The overvoltage protection module avoids the overvoltage problem caused by phase stripping and energy reduction when switching from three-phase to single-phase operation mode, thus ensuring the safety of operation mode switching.

[0053] As a third embodiment of this application, an electric heating device includes: a heating module for performing heating, a heating drive module for controlling heating power, and a single-phase / three-phase switching control system.

[0054] like Figure 2 As shown, the heating module is connected to the heating drive module and the power supply. The heating drive module is connected to the single-phase and three-phase switching control system. The single-phase and three-phase switching control system controls the heating power output of the heating drive module according to the phase judgment result of the power supply.

[0055] In other cases, electric heating devices also include a display module for real-time display of the electric heating status and for human-computer interaction with the user.

[0056] In this embodiment, the electric heating device is a rice cooker. In other embodiments, the electric heating device may also be an induction cooker, an electric pressure cooker, or other similar devices.

[0057] The specific embodiments described above are preferred embodiments of the single-phase and three-phase switching control method, system and electric heating equipment of this application, and are not intended to limit the specific implementation scope of this application. The scope of this application includes but is not limited to the specific embodiments described above. All equivalent changes made in accordance with the shape and structure of this application are within the protection scope of this application.

Claims

1. A single-phase / three-phase switching control method, applied to a frequency converter system, characterized in that: Includes the following steps: In response to power supply operation, the system acquires power supply output parameters, outputs phase judgment results based on power supply output parameters and parameter thresholds, and adjusts frequency converter parameters based on phase judgment results to control the switching between single-phase and three-phase operating modes.

2. The power supply single-phase and three-phase control method as described in claim 1, characterized in that: The step of outputting the phase judgment result based on the power supply output parameters and parameter thresholds includes: The real-time sine wave is output based on the three-phase AC waveform, and the phase judgment result is output based on the comparison result between the real-time sine wave and the three-phase waveform threshold.

3. The power supply single-phase and three-phase control method as described in claim 1, characterized in that: The parameter thresholds include at least a first parameter threshold that distinguishes between a three-phase state and a state with one phase missing, and a second parameter threshold that distinguishes between a state with one phase missing and a state with two phases missing.

4. The single-phase / three-phase switching control method as described in claim 1, characterized in that: The method of adjusting the frequency converter parameters based on the phase judgment result to control the switching between single-phase and three-phase operating modes includes: Based on the phase judgment result, the target working mode is matched, and the frequency converter parameters are adjusted according to the matching of the target working mode and the current working mode to control the switching between single and three-phase working modes.

5. The single-phase / three-phase switching control method as described in claim 4, characterized in that: The step of adjusting the frequency converter parameters according to the matching of the target operating mode and the current operating mode to control the switching between single-phase and three-phase operating modes includes: If the target operating mode is three-phase operating mode and the current operating mode is single-phase operating mode, then phase synchronization power cut-off will be performed, and the frequency converter parameters will be adjusted to adapt to the three-phase operating mode. If the target operating mode is single-phase and the current operating mode is three-phase, then phase stripping and energy reduction are performed, and the frequency converter parameters are adjusted to adapt to the single-phase operating mode.

6. A single-phase to three-phase switching control system, used to implement the method as described in any one of claims 1 to 5, characterized in that: include: Power output acquisition module, used to acquire power output parameters; The phase detection module is used to output phase judgment results based on power supply output parameters and parameter thresholds; The control module is used to adjust the frequency converter parameters based on the phase judgment result to perform single-phase and three-phase working mode switching.

7. The single-phase / three-phase switching control system as described in claim 6, characterized in that: The power output acquisition module includes a voltage AD detection module for acquiring first power output parameters and a rectification detection module for acquiring second power output parameters.

8. The single-phase / three-phase switching control system as described in claim 7, characterized in that: The control module obtains the three-phase balance degree based on the first power supply output parameters and the second power supply output parameters, outputs the balance judgment result based on the balance degree threshold and the three-phase balance degree, and adjusts the frequency conversion parameters based on the balance judgment result and the phase judgment result to perform single and three-phase working mode switching.

9. The single-phase / three-phase switching control system as described in claim 1, characterized in that: Also includes: An overvoltage protection module connected to the phase detection module and the power output acquisition module.

10. Electric heating equipment, including: The heating module for performing heating and the heating drive module for controlling the heating power are characterized in that: they further include a single-phase to three-phase switching control system as described in any one of claims 6 to 9, wherein the heating module is connected to the heating drive module, and the heating drive module is connected to the single-phase to three-phase switching control system.

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