Power supply switching control method and device and computer program product

Abstract

The invention discloses a power supply switching control method, a power supply switching control device and a computer program product, a plurality of reference voltages are generated through the voltage phase difference between a motor and a standby power supply, and the phase of the output voltage of an inverter located between the standby power supply and the motor is adjusted based on the reference voltages. Therefore, the voltage phase gradually approaches the voltage phase of the standby power supply; on the basis of the phase difference, the inverter is used for phase adjustment, non-impact switching of the motor when the main power source breaks down is achieved, the problem that in the prior art, due to the fact that the voltage phase difference between the motor and the standby power source is too large, impact current is generated, tripping is caused, and then power loss of the motor is caused again is solved, and therefore the reliability of the motor is improved. Reliable power supply to the motor is ensured, and the system is very suitable for large-scale application and popularization.

Description

Technical Field

[0001] The present invention belongs to the technical field of power supply switching control, and particularly relates to a power supply switching control method, device and computer program product. Background Art

[0002] With the rapid development of modern industrial technology, more and more important load devices in the power grid have put forward high requirements for power supply reliability. For example, in a motor drive control system, once the power supply fails due to a power grid fault, these loads will face the risk of short-term power loss, and in this case, serious economic losses may be caused.

[0003] At present, the electrical load of the aforementioned motor is usually configured with two power supplies, namely the main power supply and the standby power supply. Among them, once the main power supply fails, it can be quickly switched to the standby power supply to maintain the power supply to the motor; and after the main power supply fault is repaired, it can be switched back to the main power supply to ensure the uninterrupted operation of the load, thereby improving the reliability of the power supply.

[0004] In actual use, the standby power supply often uses an uninterruptible power supply. That is, when the main power supply fails, it is usually switched to the uninterruptible power supply to directly supply power to the motor. However, for a motor, especially a large-capacity motor, during power supply switching, due to the inertia of its internal rotor, the motor speed will not quickly become zero. At this time, an electromotive force will be induced in the stator winding. And once the phase of the induced electromotive force generated after the motor is powered off is inconsistent with the phase of the standby power supply, a voltage shock will be generated in the device, and then a current shock will be generated. Moreover, the greater the phase difference, the greater the current shock. In this way, it is very likely to cause a trip and lead to a re-power loss, thus making the motor face the risk of stopping operation again. Therefore, based on the above deficiencies, how to provide a power supply switching control method that can reduce the current shock to the motor during power supply switching has become an urgent problem to be solved. Summary of the Invention

[0005] The purpose of the present invention is to provide a power supply switching control method, device and computer program product to solve the problem that the prior art will generate a current shock to the motor during power supply switching, thereby causing the motor to lose power again.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] In the first aspect, a power supply switching control method is provided, which is applied to the switching control between a main power supply and a standby power supply. Among them, the standby power supply is electrically connected to a load motor through an inverter, and the method includes:

[0008] When the main power supply fails, collect the first voltage signal of the standby power supply and the second voltage signal of the stator winding of the load motor;

[0009] Calculate the amplitude and phase of the power supply voltage of the backup power supply according to the first voltage signal, and calculate the remaining voltage phase corresponding to the remaining induced voltage of the load motor when the main power supply fails according to the second voltage signal;

[0010] Calculate the phase difference between the remaining voltage phase and the power supply voltage phase;

[0011] Based on the phase difference, determine whether the inrush current generated during the main-to-backup power supply switchover exceeds the starting current of the load motor;

[0012] If so, generate a plurality of reference phases according to the phase difference;

[0013] Calculate the reference voltages corresponding to the respective reference phases by using the power supply voltage amplitude and the plurality of reference phases;

[0014] Based on the respective reference voltages, sequentially adjust the phase of the output voltage of the inverter until, when the adjustment is completed, connect the electrical connection between the backup power supply and the load motor, and disconnect the electrical connection between the inverter and the load motor, so as to complete the switchover between the main power supply and the backup power supply.

[0015] Based on the above-disclosed content, the present invention is provided with an inverter between the backup power supply and the load motor, and by adjusting the phase of the output voltage of the inverter, the current impact caused by the inconsistency between the phase of the induced electromotive force in the load motor and the phase of the backup power supply is mitigated; specifically, when the main power supply fails, the present invention first collects the voltage signal of the backup power supply and the voltage signal of the stator winding of the load motor; then, according to the collected voltage signals, calculates the voltage amplitude and voltage phase of the backup power supply, and the voltage phase corresponding to the induced electromotive force generated by the load motor when the main power supply fails; then, based on the phase difference between the two voltage phases, determines whether the inrush current generated during the main-to-backup power supply switchover is greater than the starting current of the load motor; wherein, if it exceeds, it indicates that a direct switchover may cause a closing failure, thereby resulting in the loss of power of the motor. At this time, the present invention generates a plurality of reference phases according to the phase difference, and calculates the reference voltages corresponding to the respective reference phases based on the foregoing power supply voltage amplitude; then, according to the respective reference voltages, sequentially adjusts the phase of the output voltage of the inverter, so as to gradually adjust the phase of the output voltage of the inverter to be consistent with the phase of the backup power supply; finally, when the adjustment is completed, disconnect the connection between the inverter and the load motor, and connect the connection between the backup power supply and the load motor, thereby realizing the smooth access of the backup power supply.

[0016] Through the above design, the present invention generates multiple reference voltages based on the voltage phase difference between the motor and the backup power supply, and based on this, adjusts the phase of the output voltage of the inverter located between the backup power supply and the motor, so that it gradually approaches the voltage phase of the backup power supply; based on this, the present invention realizes the shock-free switching of the motor when the main power supply fails by using the phase difference and the inverter for phase adjustment, avoiding the problem of the impact current generated due to the excessive voltage phase difference between the motor and the backup power supply in the traditional technology, which may cause tripping and result in the motor losing power again. Therefore, the present invention ensures reliable power supply to the motor and is thus very suitable for large-scale application and promotion.

[0017] In a possible design, the first voltage signal is the phase-A voltage signal of the backup power supply. Among them, according to the first voltage signal, calculating the power supply voltage amplitude and the power supply voltage phase of the backup power supply includes:

[0018] Obtaining the power supply parameters of the backup power supply;

[0019] Performing phase delay processing on the phase-A voltage signal to obtain a delayed voltage signal;

[0020] Based on the delayed voltage signal, the phase-A voltage signal, and the power supply parameters, converting the three-phase voltage signals of the backup power supply into two-phase rectangular coordinate voltage signals;

[0021] Calculating the power supply voltage amplitude and the power supply voltage phase of the backup power supply according to the two-phase rectangular coordinate voltage signals.

[0022] In a possible design, performing phase delay processing on the phase-A voltage signal to obtain a delayed voltage signal includes:

[0023] Obtaining the phase delay angle;

[0024] According to the phase delay angle and using the following formula (1), performing phase delay processing on the phase-A voltage signal to obtain the delayed voltage signal;

[0025]

[0026] In the above formula (1), U β represents the delayed voltage signal, U A represents the phase-A voltage signal, β represents the phase delay angle, ω represents the voltage angular frequency of the backup power supply, represents the initial phase angle of the phase-A voltage signal, t is the sampling time, and U represents the effective value of the phase voltage of the backup power supply.

[0027] In a possible design, the power supply parameters include: the voltage angular frequency of the backup power supply. The two-phase rectangular coordinate voltage signals correspond to a d-q coordinate system in a two-phase rectangular coordinate system. Among them, based on the delayed voltage signal, the phase A voltage signal, and the power supply parameters, converting the three-phase voltage signals of the backup power supply into two-phase rectangular coordinate voltage signals includes:

[0028] Converting the three-phase voltage signals of the backup power supply into two-phase rectangular coordinate voltage signals according to the following formula (2);

[0029]

[0030] In the above formula (2), U d , U q Successively represent the d-axis component and the q-axis component in the two-phase rectangular coordinate system of the backup power supply. U A Represents the phase A voltage signal, and U β Represents the delayed voltage signal, ω represents the voltage angular frequency of the backup power supply, t is the sampling time, and β represents the phase delay angle.

[0031] In a possible design, the two-phase rectangular coordinate voltage signals include the d-axis component and the q-axis component of the backup power supply in the d-q coordinate system. Among them, according to the two-phase rectangular coordinate voltage signals, calculating the power supply voltage amplitude and the power supply voltage phase of the backup power supply includes:

[0032] Calculating the power supply voltage amplitude and the power supply voltage phase according to the following formula (3);

[0033]

[0034] In the above formula (3), U′ represents the power supply voltage amplitude, θ represents the power supply voltage phase, and U d , U q Successively represent the d-axis component and the q-axis component.

[0035] In a possible design, based on the phase difference, determining whether the inrush current generated during the main-backup power supply switching exceeds the starting current of the load motor includes:

[0036] Determining whether the phase difference is within [0°, 30°) or (-30°, 0°];

[0037] If not, it is determined that the inrush current generated during the main-backup power supply switching exceeds the starting current of the load motor;

[0038] Correspondingly, generating multiple reference phases according to the phase difference includes:

[0039] Determine the phase interval to which the phase difference belongs;

[0040] Determine the number of phase divisions according to the phase interval;

[0041] Based on the number of phase divisions, perform segmentation processing on the phase difference so as to obtain multiple reference phases after the segmentation processing.

[0042] In a possible design, calculate the reference voltages corresponding to the respective reference phases by using the power supply voltage amplitude and the multiple reference phases, including:

[0043] Use the power supply voltage amplitude as the reference voltage amplitude;

[0044] According to the reference voltage amplitude and in accordance with the following formula (4), calculate the reference voltages corresponding to the respective reference phases;

[0045] VM i =V*sin(ωt+Δα i ) (4)

[0046] In the above formula (4), V represents the reference voltage amplitude, ω represents the voltage angular frequency of the standby power supply, t represents the sampling time, and Δα i represents the i-th reference phase among the multiple reference phases, and VM i represents the reference voltage corresponding to the i-th reference phase, where i = 1, 2, 3,..., n, and n represents the total number of reference phases.

[0047] In a second aspect, a power supply switching control device is provided, which is applied to the switching control between a main power supply and a standby power supply. Among them, the standby power supply is electrically connected to a load motor through an inverter, and the device includes:

[0048] A voltage sampling unit, configured to collect a first voltage signal of the standby power supply and a second voltage signal of the stator winding of the load motor when the main power supply fails;

[0049] A voltage and phase calculation unit, configured to calculate the power supply voltage amplitude and the power supply voltage phase of the standby power supply according to the first voltage signal, and calculate the remaining voltage phase corresponding to the remaining induced voltage of the load motor when the main power supply fails according to the second voltage signal;

[0050] A switching control unit, configured to calculate the phase difference between the remaining voltage phase and the power supply voltage phase;

[0051] A switching control unit, configured to determine whether the inrush current generated during the main and standby power supply switching exceeds the starting current of the load motor based on the phase difference;

[0052] If so, the switching control unit is configured to generate a plurality of reference phases according to the phase difference.

[0053] The switching control unit is configured to calculate the reference voltages corresponding to the respective reference phases by using the power supply voltage amplitude and the plurality of reference phases.

[0054] The switching control unit is further configured to sequentially adjust the phase of the output voltage of the inverter based on the respective reference voltages until, when the adjustment is completed, the electrical connection between the standby power supply and the load motor is turned on, and the electrical connection between the inverter and the load motor is turned off, so as to complete the switching between the main power supply and the standby power supply.

[0055] In a third aspect, another power supply switching control device is provided. Taking the device as an electronic device as an example, it includes a memory, a processor, and a transceiver that are communicatively connected in sequence. Among them, the memory is configured to store a computer program, the transceiver is configured to send and receive messages, and the processor is configured to read the computer program and execute the power supply switching control method as described in the first aspect or any one of the possible designs in the first aspect.

[0056] In a fourth aspect, a storage medium is provided. Instructions are stored on the storage medium, and when the instructions are run on a computer, the power supply switching control method as described in the first aspect or any one of the possible designs in the first aspect is executed.

[0057] In a fifth aspect, a computer program product including instructions is provided. When the instructions are run on a computer, the computer is caused to execute the power supply switching control method as described in the first aspect or any one of the possible designs in the first aspect.

[0058] Advantageous effects:

[0059] (1) In the present invention, a plurality of reference voltages are generated based on the voltage phase difference between the motor and the standby power supply, and based on this, the phase of the output voltage of the inverter located between the standby power supply and the motor is adjusted, so that it gradually approaches the voltage phase of the standby power supply; based on this, the present invention is based on the phase difference and uses the inverter for phase adjustment, realizing the non-impact switching of the motor when the main power supply fails, avoiding the problem of impact current generated due to the excessive voltage phase difference between the motor and the standby power supply in the traditional technology, which may cause a trip and result in the motor losing power again. Therefore, the present invention ensures reliable power supply to the motor and is thus very suitable for large-scale application and promotion.

[0060] (2) In the present invention, by collecting the single-phase voltage signals of the motor and the standby power supply, the voltage phases of the motor and the standby power supply can be directly calculated. In this way, compared with the traditional method of collecting three-phase voltage signals, the present invention can reduce the sampling data and improve the calculation speed, thus ensuring the switching speed of the main and standby power supplies. Description of the Drawings

[0061] Figure 1 Schematic diagram of the steps of the power supply switching control method provided by the embodiment of the present invention;

[0062] Figure 2 Schematic diagram of the structure of the power supply switching control device provided by the embodiment of the present invention;

[0063] Figure 3 Schematic diagram of the structure of the electronic device provided by the embodiment of the present invention. Detailed implementation manners

[0064] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the present invention in combination with the accompanying drawings and the description of the embodiments or the prior art. Obviously, the following description of the structures of the accompanying drawings is only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings. It should be noted here that the description of these embodiment modes is used to help understand the present invention, but does not constitute a limitation to the present invention.

[0065] It should be understood that although terms such as first and second may be used herein to describe various units, these units should not be limited by these terms. These terms are only used to distinguish one unit from another. For example, the first unit may be called the second unit, and similarly, the second unit may be called the first unit, without departing from the scope of the exemplary embodiments of the present invention.

[0066] It should be understood that for the term "and / or" that may appear in this article, it is only a description of the association relationship of the associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, B exists alone, and A and B exist simultaneously; for the term " / and" that may appear in this article, it is a description of another association object relationship, indicating that two relationships may exist. For example, A / and B may represent: A exists alone, and A and B exist alone; in addition, for the character " / " that may appear in this article, generally it represents that the front and rear associated objects are an "or" relationship.

[0067] Embodiment:

[0068] See Figure 1As shown, the power supply switching control method provided in this embodiment is applied to the switching control between the main power supply and the standby power supply. For example, the standby power supply is an uninterruptible power supply, and the standby power supply is electrically connected to the input end of the inverter through a rectifier, while the output end of the inverter is electrically connected to the load motor. Thus, this embodiment is equivalent to setting an inverter between the standby power supply and the load motor, and based on the voltage phase difference between the standby power supply and the motor, gradually adjusting the output voltage phase of the inverter so that it gradually approaches the voltage phase of the standby power supply; that is, first calculate the phase difference between the induced electromotive force generated by the motor when the main power supply fails and the voltage of the standby power supply; then, based on the phase difference, generate multiple reference voltages, and based on this, adjust the phase of the inverter output voltage so that it gradually approaches the voltage phase of the standby power supply; based on this, this method realizes the shock-free switching of the motor when the main power supply fails, avoiding the problem of the impact current generated due to the too large voltage phase difference between the motor and the standby power supply in the traditional technology, which may cause a trip and result in the motor losing power again. Therefore, this method ensures the reliable power supply to the motor and is thus very suitable for large-scale application and promotion; for example, this method can be but is not limited to running on the power supply switching control side. Optionally, the power supply switching control side can be but is not limited to an industrial computer. It can be understood that the foregoing execution subject does not constitute a limitation to the embodiments of the present application. Correspondingly, the running steps of this method can be but are not limited to the following steps S1 to S7 as shown.

[0069] S1. When the main power supply fails, collect the first voltage signal of the standby power supply and the second voltage signal of the stator winding of the load motor; in specific implementation, for example, the first voltage signal of the standby power supply collected is the A-phase voltage signal of the standby power supply. Of course, the second voltage signal of the load motor collected is also its corresponding A-phase voltage signal; thus, after collecting the A-phase voltage signals of the standby power supply and the load motor, based on this, the voltage amplitudes and voltage phases of the two can be calculated to select different power supply switching methods based on the voltage phase difference between the two in the subsequent process; the calculation process of the voltage amplitude and phase can be but is not limited to the following step S2 as shown.

[0070] S2. According to the first voltage signal, calculate the power supply voltage amplitude and power supply voltage phase of the standby power supply, and according to the second voltage signal, calculate the remaining voltage phase corresponding to the remaining induced voltage of the load motor when the main power supply fails; in this embodiment, to improve the data collection efficiency and calculation speed, thus ensuring the power supply switching speed, a new calculation method for voltage amplitude and phase is provided, that is, by collecting single-phase voltage, the voltage amplitude and phase are calculated; at the same time, since the calculation processes of the voltage amplitudes and phases of the standby power supply and the load motor are the same, the following takes the standby power supply as an example to elaborate on the specific calculation process of the voltage amplitude and phase.

[0071] Optionally, for example but not limited to, the following steps S21 to S24 can be adopted to calculate the amplitude and phase of the power supply voltage of the backup power supply.

[0072] S21. Obtain the power supply parameters of the backup power supply; in specific applications, for example, the power supply parameters can include but are not limited to the voltage angular frequency. Thus, after obtaining the power supply parameters, the calculation of the power supply voltage amplitude and phase can be carried out; among them, in this embodiment, the A-phase voltage signal of the backup power supply is phase-delayed to obtain a delayed voltage signal, and then, based on the delayed voltage signal, the three-phase voltage signals of the backup power supply signal are converted into the d-q coordinate system, so as to calculate the amplitude and phase of the power supply voltage of the backup power supply based on the voltage components in the d-q coordinate system.

[0073] In this embodiment, the process of phase delay processing of the A-phase voltage signal is as shown in the following step S22.

[0074] S22. Perform phase delay processing on the A-phase voltage signal to obtain a delayed voltage signal; in specific applications, for example but not limited to, first obtain the phase delay angle, and then, according to the phase delay angle, perform phase delay processing on the A-phase voltage signal to obtain the delayed voltage signal.

[0075] In specific applications, for example but not limited to, the following formula (1) can be adopted to perform phase delay processing on the A-phase voltage signal of the backup power supply.

[0076]

[0077] In the above formula (1), U β represents the delayed voltage signal, U A represents the A-phase voltage signal, β represents the phase delay angle, ω represents the voltage angular frequency of the backup power supply, represents the initial phase angle of the A-phase voltage signal, t is the sampling time, and U represents the effective value of the phase voltage of the backup power supply; in this embodiment, the value range of the phase delay angle is [5°, 15°], and specific values can be taken within this range according to actual use, which is not specifically limited here; at the same time, for example but not limited to, the zero-crossing detection method can be adopted to obtain the initial phase angle, that is, by detecting the intersection point of the A-phase voltage waveform and the time axis to determine the starting moment of the A-phase voltage waveform, so as to obtain the initial phase angle of the A-phase voltage.

[0078] Thus, through the foregoing formula (1), the phase delay of the A-phase voltage signal can be completed, thereby obtaining a delayed signal. Based on this, by performing phase delay on the A-phase voltage signal, it is actually possible to derive the B-phase and C-phase voltage signals. Then, the obtained three-phase voltage signals are converted into the d-q coordinate system, thereby calculating the amplitude and phase of the power supply voltage of the standby power supply.

[0079] Optionally, for example, but not limited to, according to the following formula (5), the B-phase voltage signal of the standby power supply can be calculated.

[0080]

[0081] In the above formula (4), U B represents the B-phase voltage signal.

[0082] After obtaining the B-phase voltage signal, the C-phase voltage can be calculated. Among them, the relationship between the three phases is: -U B =-U A -U C , thus, based on the foregoing formula, the C-phase voltage signal can be obtained. For example and:

[0083]

[0084] In the above formula (6), U C represents the C-phase voltage signal.

[0085] Thus, after calculating the B-phase and C-phase voltage signals based on the A-phase voltage of the standby power supply, the voltage signal conversion can be performed, and the process is as shown in the following step S23.

[0086] S23. Based on the delayed voltage signal, the A-phase voltage signal, and the power supply parameters, convert the three-phase voltage signals of the standby power supply into two-phase rectangular coordinate voltage signals; in this embodiment, actually convert the three-phase voltage signals of the standby power supply into the two-phase rectangular coordinate system, that is, convert them into the d-q coordinate system, thereby obtaining two-phase rectangular coordinate voltage signals.

[0087] Among them, taking the three-phase voltage signals of the standby power supply as an example, the conversion process between them and the two-phase rectangular coordinate voltage signals is described, that is, according to the following formula (7), the three-phase voltage signals of the standby power supply are converted into two-phase rectangular coordinate voltage signals.

[0088]

[0089] In the above formula (7), U d , U q successively represent the d-axis component and the q-axis component of the standby power supply in the two-phase rectangular coordinate voltage system. Among them, UA represents the A-phase voltage signal, U B represents the B-phase voltage signal, U C represents the C-phase voltage signal, ω represents the voltage angular frequency of the standby power supply, and t is the sampling time.

[0090] Based on this, substituting the foregoing expressions of U A , U B and U C into the foregoing formula (7), a conversion formula for signal conversion using only the delayed voltage signal and the A-phase voltage signal can be obtained.

[0091] Specifically, for example, according to the following formula (2), the three-phase voltage signals of the standby power supply are converted into two-phase rectangular coordinate voltage signals;

[0092]

[0093] In the above formula (2), U d , U q successively represent the d-axis component and the q-axis component in the two-phase rectangular coordinate system of the standby power supply, U A represents the A-phase voltage signal, U β represents the delayed voltage signal, ω represents the voltage angular frequency of the standby power supply, t is the sampling time, and β represents the phase delay angle.

[0094] Based on the foregoing formula (2), it can be known that in this application, only by obtaining the A-phase voltage signal of the standby power supply, the conversion between its entire three-phase voltage signal and the two-phase rectangular coordinate voltage signal can be completed; thus, based on this two-phase rectangular coordinate voltage signal, the power supply voltage amplitude and the power supply voltage phase of the standby power supply can be calculated, and the calculation process is as shown in the following step S24.

[0095] S24. Calculate the power supply voltage amplitude and the power supply voltage phase of the standby power supply according to the two-phase rectangular coordinate voltage signal; in specific implementation, as previously described, the two-phase rectangular coordinate voltage signal includes the d-axis component and the q-axis component of the standby power supply in the d-q coordinate system (where the d-q coordinate system is a synchronous reference coordinate system that rotates synchronously with the rotor of the motor), so in this embodiment, the power supply voltage amplitude and the power supply voltage phase can be calculated according to the d-axis component and the q-axis component corresponding to the three-phase voltage signal of the standby power supply and using the following formula (3).

[0096] Calculate the power supply voltage amplitude and the power supply voltage phase according to the following formula (3);

[0097]

[0098] In the above formula (3), U′ represents the amplitude of the power supply voltage, θ represents the phase of the power supply voltage, and U d , U q successively represent the d-axis component and the q-axis component respectively.

[0099] In this way, through the foregoing formula (3), the amplitude and phase of the power supply voltage of the backup power supply can be calculated; similarly, for the load motor, the calculation process of the voltage phase of the induced electromotive force generated when the main power supply fails is also the same, which will not be elaborated here one by one.

[0100] In this way, through the foregoing steps S21 to S24, this embodiment only needs to collect the single-phase voltage signals of the motor and the backup power supply to calculate the voltage amplitudes and phases of the motor and the backup power supply; based on this, compared with the traditional technology, the data sampling of the B-phase and C-phase voltages is reduced, the sampling speed can be improved, and only the single-phase voltage signal needs to be phase-delayed and then substituted into the foregoing formulas (2) and (3), and then the voltage amplitudes and phases of the motor and the backup power supply can be calculated; therefore, the calculation amount is also reduced, thus ensuring the speed of power supply switching.

[0101] After obtaining the voltage phase difference between the backup power supply and the motor, different power supply switching methods can be selected based on the phase difference value, and the process is as shown in the following steps S3 to S7.

[0102] S3. Calculate the phase difference between the remaining voltage phase and the power supply voltage phase; in this embodiment, according to the phase difference, it is judged whether the impact current generated during the main and backup power supply switching will pose a tripping risk to the load motor. Among them, if a tripping risk will occur, a phase-splitting power supply switching method needs to be adopted, otherwise, it can be directly switched; optionally, the foregoing judgment process is as shown in the following step S4.

[0103] S4. Based on the phase difference, determine whether the inrush current generated during the main and standby power supply switching exceeds the starting current of the load motor; in specific applications, it is determined by whether the phase difference is within [0°, 30°) or (-30°, 0°]. Among them, if so, that is, the phase difference is within the interval of [0°, 30°) or (-30°, 0°], then it indicates that the maximum value of the inrush current generated during the main and standby power supply switching is less than 3 times the rated current amplitude of the motor and less than the starting current of the load motor. The load motor can withstand this inrush current. Therefore, the direct switching method can be adopted to switch the main and standby power supplies, that is, directly connect the electrical connection between the standby power supply and the load motor, and disconnect the electrical connection between the inverter and the load motor, thereby completing the access of the standby power supply; on the contrary, if the aforementioned phase difference exceeds [0°, 30°) or (-30°, 0°], it indicates that the inrush current generated during the main and standby power supply switching is greater than the starting current of the motor and the motor cannot withstand it. Therefore, if the direct switching method is adopted, it may cause a trip and lead to the motor losing power again; based on this, this embodiment provides a power supply switching method that can reduce the current impact, and its switching process is shown in the following steps S5 to S7.

[0104] S5. If so, generate multiple reference phases according to the phase difference; in this embodiment, for example, but not limited to, first determine the phase interval to which the phase difference belongs; then, according to the phase interval, determine the number of phase segmentation times; finally, based on the number of phase segmentation times, perform segmentation processing on the phase difference to obtain multiple reference phases after the segmentation processing.

[0105] Optionally, the phase intervals set in this embodiment are: [30°, 60°), [60°, 90°), [90°, 180°), (-60°, -30°], (-90°, -60°], (-180°, -90°]; among them, the number of phase segmentation times corresponding to [30°, 60°) and (-60°, -30°] is 2 times, the number of phase segmentation times corresponding to [60°, 90°) and (-90°, -60°] is 4 times, and the number of phase segmentation times corresponding to [90°, 180°) and (-180°, -90°] is 8 times.

[0106] Among them, assuming that the phase difference is 135°, then the corresponding number of phase segmentation times is 8 times. Therefore, it is equivalent to dividing 135° into 8 parts, and the difference between adjacent two reference phases is 135° / 8 = 16.875°. Based on this, when the phase difference is 135°, 8 reference phases will be obtained, which are 16.875°, 33.75°, 50.625°, 67.5°, 84.375°, 101.254°, 118.125°, and 135° in sequence. Of course, the foregoing example is only illustrative. When the phase difference is other values, the corresponding number of phase segmentation times and the determination process of the reference phases are the same as those in the foregoing example, which will not be elaborated herein.

[0107] After determining multiple reference phases, based on this, the reference voltages corresponding to each reference phase can be calculated, so as to subsequently adjust the output voltage of the inverter based on the calculated reference voltages. Among them, the calculation process of the reference voltage can be but is not limited to the following steps shown in S6.

[0108] S6. Use the power supply voltage amplitude and multiple reference phases to calculate the reference voltages corresponding to each reference phase; in this embodiment, first use the power supply voltage amplitude as the reference voltage amplitude; then, according to the reference voltage amplitude, calculate the reference voltages corresponding to each reference phase.

[0109] Among them, for example, the calculation can be but is not limited to the following formula (4).

[0110] VM i = V*sin(ωt + Δα i ) (4)

[0111] In the above formula (4), V represents the reference voltage amplitude, ω represents the voltage angular frequency of the standby power supply, t represents the sampling time, Δα i represents the i-th reference phase among multiple reference phases, VM i represents the reference voltage corresponding to the i-th reference phase, where i = 1, 2, 3,..., n, and n represents the total number of reference phases.

[0112] In this way, substituting each reference phase into the foregoing formula (4) respectively, the reference voltages corresponding to each reference phase can be calculated. Then, based on each reference voltage, the control of the output voltage of the inverter can be carried out, so as to adjust the phase of the output voltage of the inverter to be consistent with the phase of the standby power supply, thereby realizing a shock-free switch to the standby power supply. Among them, the switching process is as shown in the following steps S7.

[0113] S7. Based on each reference voltage, sequentially adjust the phase of the output voltage of the inverter until, when the adjustment is completed, connect the electrical connection between the standby power supply and the load motor, and disconnect the electrical connection between the inverter and the load motor to complete the switching between the main power supply and the standby power supply; in specific applications, it is equivalent to first using the reference voltage corresponding to the first reference phase to adjust the phase of the output voltage of the inverter, and then using the reference voltage corresponding to the second reference phase to adjust the phase of the output voltage of the inverter. Based on this principle, until all reference voltages are polled, at this time, the adjustment of the phase of the output voltage of the inverter can be completed.

[0114] In this embodiment, for example, the inverter is an SVPWM inverter (i.e., a space vector modulation inverter), and its output voltage follows the reference voltage. Therefore, by changing the phase of the reference voltage of the inverter, the phase of its output voltage can be changed, making the output voltage phase closer to the standby power supply voltage phase; of course, adjusting the phase of the output voltage of the inverter according to the reference voltage is a common technique for controlling the output voltage of the inverter, and its principle will not be elaborated here.

[0115] In this way, when the adjustment of the phase of the output voltage of the inverter is completed according to each reference voltage, its output voltage phase can be gradually adjusted to be consistent with the voltage phase of the standby power supply. Based on this, after the adjustment is completed, the electrical connection between the standby power supply and the load motor can be connected, and the electrical connection between the inverter and the load motor can be disconnected, thereby realizing the smooth access of the standby power supply and further achieving the purpose of reducing the closing impact.

[0116] Thus, through the power supply switching control method detailed in the foregoing steps S1 to S7, the present invention first calculates the phase difference between the induced electromotive force generated by the motor when the main power supply fails and the voltage of the standby power supply; then, based on the phase difference, generates multiple reference voltages, and based on this, adjusts the phase of the output voltage of the inverter, so that it gradually approaches the voltage phase of the standby power supply; based on this, the present invention realizes the shockless switching of the motor when the main power supply fails, avoiding the problem that the traditional technology generates impact current due to the large phase difference between the voltage of the motor and the standby power supply, which may cause tripping and result in the motor losing power again. Therefore, the present invention ensures the reliable power supply to the motor and is thus very suitable for large-scale application and promotion.

[0117] As Figure 2 shown, the second aspect of this embodiment provides a hardware device for implementing the power supply switching control method described in the first aspect of the embodiment, including:

[0118] A voltage sampling unit, configured to collect a first voltage signal of the standby power supply and a second voltage signal of the stator winding of the load motor when the main power supply fails.

[0119] A voltage and phase calculation unit, configured to calculate the amplitude and phase of the power supply voltage of the standby power supply according to the first voltage signal, and calculate the remaining voltage phase corresponding to the remaining induced voltage of the load motor when the main power supply fails according to the second voltage signal.

[0120] A switching control unit, configured to calculate the phase difference between the remaining voltage phase and the power supply voltage phase.

[0121] The switching control unit is configured to determine whether the inrush current generated during the main and standby power supply switching exceeds the starting current of the load motor based on the phase difference.

[0122] If so, the switching control unit is configured to generate multiple reference phases according to the phase difference.

[0123] The switching control unit is configured to calculate the reference voltages corresponding to the respective reference phases by using the power supply voltage amplitude and the multiple reference phases.

[0124] The switching control unit is further configured to sequentially adjust the phase of the output voltage of the inverter based on the respective reference voltages until, when the adjustment is completed, connect the electrical connection between the standby power supply and the load motor, and disconnect the electrical connection between the inverter and the load motor, so as to complete the switching between the main power supply and the standby power supply.

[0125] For the working process, working details and technical effects of the device provided in this embodiment, reference can be made to the first aspect of the embodiment, which will not be elaborated here.

[0126] As Figure 3 shown, a third aspect of this embodiment provides another power supply switching control device. Taking the device as an electronic device as an example, it includes: a memory, a processor, and a transceiver that are communicatively connected in sequence, where the memory is used to store a computer program, the transceiver is used to send and receive messages, and the processor is used to read the computer program and execute the power supply switching control method described in the first aspect of the embodiment.

[0127] Specifically, the memory may include, but is not limited to, random access memory (RAM), read only memory (ROM), flash memory, first input first output (FIFO), and / or first in last out (FILO), etc.; specifically, the processor may include one or more processing cores, such as a quad-core processor, an octa-core processor, etc. The processor may be implemented in at least one hardware form of DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), or PLA (Programmable Logic Array). At the same time, the processor may also include a main processor and a coprocessor. The main processor is a processor used to process data in the wake state, also known as the CPU (Central Processing Unit); the coprocessor is a low-power processor used to process data in the standby state.

[0128] In some embodiments, the processor may be integrated with a GPU (Graphics Processing Unit), and the GPU is responsible for rendering and drawing the content to be displayed on the display screen. For example, the processor may not be limited to using a microprocessor of the STM32F105 series, a reduced instruction set computer (RISC) microprocessor, an X86 architecture processor, or a processor integrated with an embedded neural-network processing unit (NPU); the transceiver may include, but is not limited to, a Wi-Fi wireless transceiver, a Bluetooth wireless transceiver, a General Packet Radio Service (GPRS) wireless transceiver, a ZigBee (a low-power local area network protocol based on the IEEE802.15.4 standard) wireless transceiver, a 3G transceiver, a 4G transceiver, and / or a 5G transceiver, etc. In addition, the device may also include, but is not limited to, a power module, a display screen, and other necessary components.

[0129] For the working process, working details, and technical effects of the electronic device provided in this embodiment, reference may be made to the first aspect of the embodiment, which will not be elaborated here.

[0130] In the fourth aspect of this embodiment, a storage medium storing instructions for implementing the power switching control method described in the first aspect of the embodiment is provided, that is, instructions are stored on the storage medium, and when the instructions run on a computer, they execute the power switching control method described in the first aspect of the embodiment.

[0131] Among them, the storage medium refers to a carrier for storing data, and may include, but is not limited to, floppy disks, optical discs, hard disks, flash memories, USB flash drives, and / or memory sticks, etc. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices.

[0132] For the working process, working details, and technical effects of the storage medium provided in this embodiment, reference may be made to the first aspect of the embodiment, and details will not be elaborated here.

[0133] In the fifth aspect of this embodiment, a computer program product containing instructions is provided. When the instructions run on a computer, the computer is caused to execute the power switching control method described in the first aspect of the embodiment, where the computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices.

[0134] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A power supply switching control method, characterized in that, Applied to the switching control between the main power supply and the standby power supply, wherein the standby power supply is electrically connected to the load motor through an inverter, and the method includes: When the main power supply fails, collect the first voltage signal of the standby power supply and the second voltage signal of the stator winding of the load motor; According to the first voltage signal, calculate the power supply voltage amplitude and power supply voltage phase of the standby power supply, and according to the second voltage signal, calculate the remaining voltage phase corresponding to the remaining induced voltage of the load motor when the main power supply fails; Calculate the phase difference between the remaining voltage phase and the power supply voltage phase; Based on the phase difference, determine whether the inrush current generated during the main and standby power supply switching exceeds the starting current of the load motor; If so, generate multiple reference phases according to the phase difference; Using the power supply voltage amplitude and multiple reference phases, calculate the reference voltages corresponding to each reference phase; Based on each reference voltage, sequentially adjust the phase of the output voltage of the inverter until the adjustment is completed, then connect the standby power supply and the load motor electrically, and disconnect the inverter and the load motor electrically to complete the switching between the main power supply and the standby power supply.

2. The method according to claim 1, wherein The first voltage signal is the A-phase voltage signal of the standby power supply, wherein, according to the first voltage signal, calculating the power supply voltage amplitude and power supply voltage phase of the standby power supply includes: Obtain the power supply parameters of the standby power supply; Perform phase delay processing on the A-phase voltage signal to obtain a delayed voltage signal; Based on the delayed voltage signal, the A-phase voltage signal and the power supply parameters, convert the three-phase voltage signals of the standby power supply into two-phase rectangular coordinate voltage signals; According to the two-phase rectangular coordinate voltage signals, calculate the power supply voltage amplitude and power supply voltage phase of the standby power supply.

3. The method according to claim 2, wherein Performing phase delay processing on the A-phase voltage signal to obtain a delayed voltage signal includes: Obtain the phase delay angle; According to the phase delay angle and using the following formula (1), perform phase delay processing on the A-phase voltage signal to obtain the delayed voltage signal; In the above formula (1), U β represents the delay voltage signal, U A represents the phase-A voltage signal, β represents the phase delay angle, ω represents the voltage angular frequency of the standby power supply, represents the initial phase angle of the phase-A voltage signal, t is the sampling time, and U represents the effective value of the phase voltage of the standby power supply.

4. The method according to claim 2, wherein The power supply parameters include: the voltage angular frequency of the standby power supply, and the two-phase rectangular coordinate system corresponding to the two-phase rectangular coordinate voltage signals is the d-q coordinate system, wherein, based on the delayed voltage signal, the A-phase voltage signal and the power supply parameters, converting the three-phase voltage signals of the standby power supply into two-phase rectangular coordinate voltage signals includes: According to the following formula (2), convert the three-phase voltage signals of the standby power supply into two-phase rectangular coordinate voltage signals; In the above formula (2), U d , U q respectively represent the d-axis component and the q-axis component of the standby power supply in the two-phase rectangular coordinate system, U A represents the phase A voltage signal, U β represents the delayed voltage signal, ω represents the voltage angular frequency of the standby power supply, t is the sampling time, and β represents the phase delay angle.

5. The method according to claim 2, characterized in that The two-phase rectangular coordinate voltage signals include the d-axis component and the q-axis component of the standby power supply in the d-q coordinate system, wherein, according to the two-phase rectangular coordinate voltage signals, calculating the power supply voltage amplitude and power supply voltage phase of the standby power supply includes: According to the following formula (3), calculate the power supply voltage amplitude and the power supply voltage phase; In the above formula (3), U′ represents the amplitude of the power supply voltage, θ represents the phase of the power supply voltage, and U d , U q successively represent the d-axis component and the q-axis component.

6. The method according to claim 1, characterized in that, Based on the phase difference, determining whether the inrush current generated during the main and standby power supply switching exceeds the starting current of the load motor includes: Determine whether the phase difference is in the range of [0°, 30°) or (-30°, 0°]; Otherwise, it is determined that the inrush current generated during the main and standby power supply switching exceeds the starting current of the load motor; Correspondingly, according to the phase difference, a plurality of reference phases are generated, including: Determine the phase interval to which the phase difference belongs; According to the phase interval, determine the number of phase divisions; Based on the number of phase divisions, the phase difference is divided to obtain a plurality of reference phases after the division process.

7. The method according to claim 1, characterized in that Using the power supply voltage amplitude and a plurality of reference phases, calculate the reference voltage corresponding to each reference phase, including: Use the power supply voltage amplitude as the reference voltage amplitude; According to the reference voltage amplitude and in accordance with the following formula (4), calculate the reference voltage corresponding to each reference phase; VM i = V * sin(ωt + Δα i ) (4) In the above formula (4), V represents the amplitude of the reference voltage, ω represents the angular frequency of the standby power supply, t represents the sampling time, and Δα i represents the i-th reference phase among a plurality of reference phases, and VM i represents the reference voltage corresponding to the i-th reference phase, where i = 1, 2, 3,..., n, and n represents the total number of reference phases.

8. A power supply switching control device, characterized in that, Applied to the switching control between the main power supply and the standby power supply, wherein the standby power supply is electrically connected to the load motor through an inverter, and the device includes: A voltage sampling unit for collecting a first voltage signal of the standby power supply and a second voltage signal of the stator winding of the load motor when the main power supply fails; A voltage and phase calculation unit for calculating the power supply voltage amplitude and the power supply voltage phase of the standby power supply according to the first voltage signal, and calculating the remaining voltage phase corresponding to the remaining induced voltage of the load motor when the main power supply fails according to the second voltage signal; A switching control unit for calculating the phase difference between the remaining voltage phase and the power supply voltage phase; A switching control unit for determining whether the inrush current generated during the main and standby power supply switching exceeds the starting current of the load motor based on the phase difference; If so, the switching control unit is used to generate a plurality of reference phases according to the phase difference; A switching control unit for calculating the reference voltage corresponding to each reference phase by using the power supply voltage amplitude and a plurality of reference phases; The switching control unit is further used to sequentially adjust the phase of the output voltage of the inverter based on each reference voltage until the adjustment is completed, then connect the standby power supply and the load motor electrically, and disconnect the inverter and the load motor electrically to complete the switching between the main power supply and the standby power supply.

9. A power supply switching control device, characterized in that, Including: A memory, a processor, and a transceiver that are communicatively connected in sequence, wherein the memory is used to store a computer program, the transceiver is used to send and receive messages, and the processor is used to read the computer program and execute the power supply switching control method according to any one of claims 1 to 7.

10. A computer program product comprising instructions, characterized in that, When the instruction runs on a computer, the computer executes the power supply switching control method according to any one of claims 1 to 7.

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