Voltage control method and device, system, equipment and medium of variable frequency power supply system

Abstract

The embodiment of the present application provides a voltage control method and device, system, equipment and medium of a variable frequency power supply system, the method comprises the following steps: acquiring an incoming line voltage and an outgoing line current of the variable frequency power supply system; wherein the incoming line voltage is a voltage value of an incoming line side of a rectifier in the variable frequency power supply system, and the outgoing line current is a current value of an outgoing line side of an inverter in the variable frequency power supply system; calculating a direct current bus voltage set value according to the incoming line voltage and the outgoing line current; inputting the direct current bus voltage set value into the rectifier, so that the rectifier performs closed-loop control according to the direct current bus voltage set value, so that a difference between a direct current bus voltage value output by the rectifier and an output voltage of the variable frequency power supply system remains dynamic balance. The present application can improve the output power supply quality of the variable frequency power supply system.

Description

Technical Field

[0001] This invention relates to the field of power supply technology, and in particular to a voltage control method and device for a frequency converter power supply system, a frequency converter power supply system, a computing device, and a computer-readable medium. Background Technology

[0002] An AFE (Active Front End) frequency converter can be used as a variable frequency power supply to provide stable frequency and voltage power for electrical equipment requiring 60Hz or other frequencies. When an AFE frequency converter is used as a power supply device, the quality of the output power is an important technical indicator. In addition to ensuring stable output AC voltage and frequency, the output voltage harmonics must also meet standard requirements across the entire load range. Summary of the Invention

[0003] This invention provides a voltage control method and apparatus for a variable frequency power supply system, a variable frequency power supply system, a computing device, and a computer-readable medium, which can improve the output power quality of the variable frequency power supply system.

[0004] In a first aspect, one embodiment of the present invention provides a voltage control method for a frequency converter power supply system, comprising:

[0005] Obtain the input voltage and output current of the variable frequency power supply system; wherein, the input voltage is the voltage value of the input side of the rectifier in the variable frequency power supply system, and the output current is the current value of the output side of the inverter in the variable frequency power supply system.

[0006] Calculate the DC bus voltage setpoint based on the incoming line voltage and the outgoing line current;

[0007] The DC bus voltage setting value is input to the rectifier so that the rectifier performs closed-loop control according to the DC bus voltage setting value, so that the difference between the DC bus voltage value output by the rectifier and the output voltage of the frequency converter power supply system is kept in dynamic balance.

[0008] Optionally, calculating the DC bus voltage setpoint based on the incoming line voltage and the outgoing line current includes:

[0009] Obtain the output voltage setting value of the variable frequency power supply system, and calculate the reference DC bus voltage setting value based on the output voltage setting value and the input voltage;

[0010] Obtain the preset parameter values ​​on the output side of the variable frequency power supply system, and calculate the voltage compensation value based on the preset parameter values ​​and the output current; wherein, the preset parameter values ​​are the values ​​of the parameters on the output side that affect the output power quality of the variable frequency power supply system;

[0011] The DC bus voltage setting value is determined based on the reference DC bus voltage setting value and the voltage compensation value.

[0012] Furthermore, the step of calculating the reference DC bus voltage setting value based on the output voltage setting value and the input line voltage includes: calculating the reference DC bus voltage setting value using a first calculation formula, wherein the first calculation formula is:

[0013] U1=U Lrated *K+ U outsp * K outsp + U Line * K Line

[0014] In the formula, U1 is the reference DC bus voltage setting value, U Lrated U is the rated voltage of the incoming line, K is the rectification factor, and U is the current. outsp K is the set value for the output voltage. outsp U is the output voltage influence factor. Line K is the input voltage. Line This is the factor affecting the incoming line voltage.

[0015] Furthermore, the step of calculating the voltage compensation value based on the preset parameter value and the outgoing line current includes: calculating the voltage compensation value using a second calculation formula, wherein the second calculation formula is:

[0016] U2= K Iout *(U Trated *Z Tout *I out / I TIN + I out *Z cable / G+ I out *Z load )

[0017] In the formula, U2 is the voltage compensation value, K Iout U is the influencing factor of outgoing line current. Trated Z is the rated voltage of the low-voltage side of the output transformer in the output side. Tout I is the impedance of the outgoing transformer. Out For the outgoing line current, I TIN Z is the rated current on the low-voltage side of the outgoing transformer. cable Z is the impedance of the output cable on the output side; G is the turns ratio of the output transformer; Z load The impedance of the load on the output side.

[0018] Furthermore, the DC bus voltage setting value is a target setting value. Correspondingly, determining the DC bus voltage setting value based on the reference DC bus voltage setting value and the voltage compensation value includes:

[0019] The initial setting value of the DC bus voltage is obtained by summing the reference DC bus voltage setting value and the voltage compensation value; it is then determined whether the initial setting value is within a preset range; if so, the initial setting value is used as the target setting value.

[0020] Optionally, the method further includes: if the initial setting value is greater than the upper limit of the preset range, then the upper limit of the preset range is used as the target setting value.

[0021] Optionally, the method further includes: if the initial setting value is less than the lower limit of the preset range, then the lower limit of the preset range is used as the target setting value.

[0022] In a second aspect, embodiments of the present invention provide a voltage control device for a frequency converter power supply system, comprising:

[0023] The acquisition module is used to: acquire the input voltage and output current of the frequency converter power supply system; wherein the input voltage is the voltage value of the input side of the rectifier in the frequency converter power supply system, and the output current is the current value of the output side of the inverter in the frequency converter power supply system.

[0024] The calculation module is used to: calculate the DC bus voltage setpoint based on the incoming line voltage and the outgoing line current;

[0025] The input module is used to input the DC bus voltage setting value into the rectifier so that the rectifier performs closed-loop control according to the DC bus voltage setting value, so that the difference between the DC bus voltage value output by the rectifier and the output voltage of the frequency converter power supply system is kept in dynamic balance.

[0026] Thirdly, embodiments of the present invention provide a variable frequency power supply system, including an incoming transformer, a rectifier, an inverter, and an outgoing transformer connected in sequence. The variable frequency power supply system also includes a controller, which is connected to a first node, a second node, and the rectifier. The first node is the node between the incoming transformer and the rectifier, and the second node is the node between the inverter and the outgoing transformer. The controller is a voltage control device provided in the second aspect.

[0027] Fourthly, one embodiment of the present invention provides a computing device, characterized in that the device includes: at least one memory and at least one processor;

[0028] The at least one memory is used to store a machine-readable program;

[0029] The at least one processor is configured to invoke the machine-readable program to execute the method provided in the first aspect.

[0030] Fifthly, one embodiment of the present invention provides a computer-readable medium storing computer instructions that, when executed by a processor, cause the processor to perform the method provided in the first aspect.

[0031] The voltage control method and device for a variable frequency power supply system, the variable frequency power supply system, the computing device, and the computer-readable medium provided in this embodiment of the invention first obtain the input voltage and output current of the variable frequency power supply system, then calculate the DC bus voltage setpoint based on the input voltage and output current, and then input the DC bus voltage setpoint into the rectifier to realize the adjustment and control of the DC bus voltage value. The output voltage of a variable frequency power supply system is affected by the load, output cables, and other output-side equipment. Similarly, the output current is also affected by these factors. The DC bus voltage setting value is calculated taking into account the magnitude of the output current. The DC bus voltage setting value calculated based on the output current and input voltage is also affected by the load, output cables, and other output-side equipment. This ensures that even when the load is too large or overloaded, the difference between the rectifier's output DC bus voltage and the variable frequency power supply system's output voltage can maintain a dynamic balance. That is, when the output voltage increases, the DC bus voltage setting value increases, thus increasing the DC bus voltage value. This keeps the difference between the output voltage and the DC bus voltage stable, thereby improving the power quality of the variable frequency power supply system output and reducing harmonics to meet the requirement of less than 5%. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of a frequency converter power supply system in one embodiment of the present invention;

[0034] Figure 2 This is a schematic flowchart of a voltage control method for a frequency converter power supply system in one embodiment of the present invention;

[0035] Figure 3 This is a flowchart illustrating a specific implementation of step S120 in one embodiment of the present invention;

[0036] Figure 4 This is a structural block diagram of the voltage control device of a frequency converter power supply system in one embodiment of the present invention;

[0037] Figure 5 This is a schematic diagram of the structure of a frequency converter power supply system in one embodiment of the present invention;

[0038] 100 Voltage control device for variable frequency power supply system 110 Get Module 120 Calculation module 130 Input module 200 Variable frequency power supply system 210 Incoming transformer 220 rectifier 230 Inverter 240 Outgoing transformer 250 controller A First node B Second node S110~S130, S121~S123 step Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0040] In a first aspect, one embodiment of the present invention provides a voltage control method for a variable frequency power supply system.

[0041] Among them, see Figure 1 The variable frequency power supply system 200 includes an input transformer 210, a rectifier 220, an inverter 230, and an output transformer 240. The output transformer 240 is connected to the load equipment via an output cable, thereby supplying power to the load equipment. The input transformer 210 transforms the input AC voltage according to a certain ratio to obtain the input voltage. The input voltage is then processed by the rectifier 220 to obtain the DC bus voltage. The DC bus voltage is then processed by the inverter 230 to obtain the AC voltage. The current output by the inverter 230 is called the output current. The output current enters the output transformer 240 to obtain the output voltage of the variable frequency power supply system 200. The output voltage supplies power to the load equipment via a cable.

[0042] To maintain stable output voltage under various loads, the variable frequency power supply system 200 needs to dynamically compensate for voltage losses in the output cables and output transformer 240. It automatically compensates for output AC voltage changes based on load variations. This compensation control method causes changes in the difference between the DC bus voltage and the system output AC voltage; the difference decreases when the output voltage increases and increases when it decreases. These voltage difference variations severely affect the quality of the output AC power supply from the variable frequency power supply system 200, causing harmonics to exceed the theoretical range, i.e., voltage harmonics greater than 5%.

[0043] Therefore, the present invention Figure 1The variable frequency power supply system 200 shown includes an added controller 250, which is used to execute the voltage control method provided in the embodiments of the present invention, thereby improving the quality of the output power supply.

[0044] In light of this situation, the present invention provides a voltage control method for a variable frequency power supply system. See also... Figure 2 The method provided in this embodiment of the invention includes the following steps S110~S130:

[0045] S110. Obtain the input voltage and output current of the frequency converter power supply system; wherein, the input voltage is the voltage value of the input side of the rectifier in the frequency converter power supply system, and the output current is the current value of the output side of the inverter in the frequency converter power supply system.

[0046] The input voltage is the voltage value on the input side of the rectifier in the frequency converter power supply system, that is, the voltage value input to the rectifier, and also the voltage value output from the input transformer.

[0047] The outgoing current is the current value on the outgoing side of the inverter, that is, the current output from the inverter, which is also the current entering the outgoing transformer.

[0048] S120. Calculate the DC bus voltage setting value based on the incoming line voltage and the outgoing line current;

[0049] Understandably, in real-world scenarios, the outgoing line current changes as the load changes, thus reflecting the load variation. Therefore, this step calculates the DC bus voltage setting based on the outgoing line current to obtain a DC bus voltage setting that suits the load conditions.

[0050] Furthermore, the input voltage is the AC voltage that enters the rectifier. The input voltage can reflect the input AC voltage of the frequency converter power supply system. Therefore, by calculating the DC bus voltage setting value based on the input voltage, a DC bus voltage setting value that conforms to the overall input situation of the frequency converter power supply system can be obtained.

[0051] As can be seen, by calculating the DC bus voltage setting value based on the input voltage and output current, a DC bus voltage setting value that meets both the load conditions and the overall input conditions can be obtained.

[0052] S130. Input the DC bus voltage setting value into the rectifier so that the rectifier performs closed-loop control according to the DC bus voltage setting value, so that the difference between the DC bus voltage value output by the rectifier and the output voltage of the frequency converter power supply system is kept in dynamic balance.

[0053] Understandably, when the DC bus voltage setting value is input to the rectifier, the rectifier will perform voltage transformation according to the DC bus voltage setting value and output the DC bus voltage value. Moreover, the DC bus voltage value output by the rectifier is almost equal to the DC bus voltage setting value, which is the original function of the rectifier.

[0054] Understandably, the output voltage of a frequency converter power supply system is affected by the load, output cables, and other output-side equipment. Similarly, the output current is also affected by these factors. The DC bus voltage setting value is calculated taking into account the magnitude of the output current. The DC bus voltage setting value calculated based on the output current and input voltage is also affected by the load, output cables, and other output-side equipment. This ensures that even when the load is too large or overloaded, the difference between the DC bus voltage value output by the rectifier and the output voltage of the frequency converter power supply system can basically maintain a dynamic balance. That is, when the output voltage increases, the DC bus voltage setting value increases, thus increasing the DC bus voltage value. This keeps the difference between the output voltage and the DC bus voltage value stable, thereby improving the power quality of the frequency converter power supply system output and reducing harmonics, ensuring that the harmonics meet the requirement of less than 5%.

[0055] In one embodiment, see Figure 3 The above step S120 may specifically include S121~S123:

[0056] S121. Obtain the output voltage setting value of the variable frequency power supply system, and calculate the reference DC bus voltage setting value based on the output voltage setting value and the input voltage.

[0057] The output voltage setting value is the voltage value required by the load, so the output voltage setting value can be set according to the actual needs of the load.

[0058] The reference DC bus voltage setting value is a reference value set based on the incoming line voltage and the voltage value required by the load. The DC bus voltage setting value can be obtained by making certain corrections or other processing based on the reference DC bus voltage setting value.

[0059] In specific implementation, the reference DC bus voltage setting value can be calculated using a first calculation formula in S121. The first calculation formula is:

[0060] U1=U Lrated *K+ U outsp * K outsp + U Line * K Line

[0061] In the formula, U1 is the reference DC bus voltage setting value, U Lrated U is the rated voltage of the incoming line, K is the rectification factor, and U is the current.outsp K is the set value for the output voltage. outsp U is the output voltage influence factor. Line K is the input voltage. Line This is the factor affecting the incoming line voltage.

[0062] As can be seen from the first calculation formula, in calculating the reference DC bus voltage setting value, in addition to considering the input voltage and output voltage setting values, the rated input voltage is also considered, along with the output voltage influence factor and the input voltage influence factor. The rated input voltage is a fixed value and can be set according to actual usage. The output voltage influence factor refers to the combined value of various parameters affecting the output voltage; it is an empirical value, generally ranging from 1.5 to 2, and can be adjusted based on actual feedback. The input voltage influence factor is also an empirical value, generally ranging from -2 to -1.5, and can be adjusted based on actual feedback. Therefore, the first calculation formula considers various factors affecting the output and input voltages, ensuring that the reference DC bus voltage value calculated by the first formula conforms to actual scenario conditions and has high reference value.

[0063] The rectification factor K is typically set to 1.5 to 2.

[0064] S122. Obtain the preset parameter values ​​on the output side of the frequency converter power supply system, and calculate the voltage compensation value based on the preset parameter values ​​and the output current; wherein, the preset parameter values ​​are the values ​​of the parameters on the output side that affect the output power quality of the frequency converter power supply system;

[0065] The preset parameter values ​​on the output side are the values ​​of various factors that affect the output power quality. Based on the preset parameter values ​​and the output line current, the voltage compensation value is calculated to ensure that the calculated voltage compensation value conforms to the actual situation of each load device on the output side.

[0066] Among these factors are preset parameters on the output side, such as the impedance, rated current, and rated voltage of the output transformer, as well as the impedance of the output cable and the equivalent impedance of the load. All of these factors can affect power quality.

[0067] In specific implementation, the voltage compensation value can be calculated using a second calculation formula in S122. The second calculation formula is:

[0068] U2= K Iout *(U Trated *Z Tout *I out / I TIN+ I out *Z cable / G+ I out *Z load )

[0069] In the formula, U2 is the voltage compensation value, K Iout U is the influencing factor of outgoing line current. Trated Z is the rated voltage of the low-voltage side of the output transformer in the output side. Tout I is the impedance of the outgoing transformer. Out For the outgoing line current, I TIN Z is the rated current on the low-voltage side of the outgoing transformer. cable Z is the impedance of the output cable on the output side; G is the turns ratio of the output transformer; Z load The impedance of the load on the output side.

[0070] As can be seen from the second calculation formula, the preset parameter values ​​considered include the rated voltage and rated current of the low-voltage side of the outgoing transformer, the impedance and turns ratio of the outgoing transformer, and the impedance of the cable and load. If the actual impedance of the cable is difficult to calculate, the theoretical impedance can be used. The load impedance can be the equivalent impedance of each load.

[0071] Furthermore, the second calculation formula also considers the influence factor of the outgoing line current. This factor is an empirical value, and its value ranges from 0.01 to 0.1. It can be adjusted according to actual feedback.

[0072] In other words, the compensation value calculated based on the second calculation formula above takes into account various factors affecting the quality of the output power supply, so that the calculated compensation value conforms to the actual scenario.

[0073] S123. Determine the DC bus voltage setting value based on the reference DC bus voltage setting value and the voltage compensation value.

[0074] Understandably, by adding a voltage compensation value to the reference DC bus voltage setting value for certain corrections, the DC bus voltage setting value can be calculated.

[0075] However, in real-world scenarios, for various reasons, such as an inappropriate value for a parameter or an error in the calculation of another parameter, the DC bus voltage setting may become unreasonable. Therefore, a preset range is set, and only the DC bus voltage setting within this range is the final setting; otherwise, some limiting processing is required.

[0076] In its specific implementation, S123 may include the following steps:

[0077] The initial setting value of the DC bus voltage is obtained by summing the reference DC bus voltage setting value and the voltage compensation value; it is then determined whether the initial setting value is within a preset range; if so, the initial setting value is used as the target setting value.

[0078] In other words, the reference DC bus voltage setting value and the voltage compensation value are summed to obtain an initial setting value. Then, it is determined whether the initial setting value is within the preset range. If it is within the preset range, the initial setting value is used as the target setting value of the DC bus voltage.

[0079] Of course, S123 may also include: if the initial setting value is greater than the upper limit of the preset range, then the upper limit of the preset range shall be used as the target setting value.

[0080] In other words, if the initial setting value is higher than the upper limit value, it means that the initial setting value is too large. In this case, the upper limit value of the preset range is directly used as the target setting value of the DC bus voltage.

[0081] Furthermore, S123 may also include: if the initial setting value is less than the lower limit of the preset range, then the lower limit of the preset range shall be used as the target setting value.

[0082] In other words, if the initial setting value is lower than the lower limit value, it means that the initial setting value is too small. In this case, the lower limit value of the preset range is directly used as the target setting value.

[0083] The voltage control method provided in this invention first obtains the input voltage and output current of the frequency converter power supply system, then calculates the DC bus voltage setpoint based on the input voltage and output current, and finally inputs the DC bus voltage setpoint into the rectifier to achieve regulation and control of the DC bus voltage value. The output voltage of the frequency converter power supply system is affected by the load, output cables, and other output-side equipment. Similarly, the output current is also affected by these factors. The calculation of the DC bus voltage setpoint takes into account the magnitude of the output current. The DC bus voltage setpoint calculated based on the output current and input voltage is also affected by the load, output cables, and other output-side equipment. This ensures that even when the load is too large or overloaded, the difference between the DC bus voltage value output by the rectifier and the output voltage of the frequency converter power supply system can maintain a dynamic balance. That is, when the load increases, the output voltage increases, and the DC bus voltage setpoint increases, thus increasing the DC bus voltage value. As can be seen, this embodiment of the invention improves the power quality of the inverter power supply system by dynamically adjusting the DC bus voltage, thereby keeping the difference between the output voltage and the DC bus voltage stable and reducing harmonics to meet the requirement of less than 5%. The method provided by this embodiment of the invention does not require capacity expansion, and therefore does not increase costs.

[0084] Secondly, embodiments of the present invention provide a voltage control device for a frequency converter power supply system.

[0085] See Figure 4 The device 100 may include:

[0086] The acquisition module 110 is used to: acquire the input voltage and output current of the frequency converter power supply system; wherein, the input voltage is the voltage value of the input side of the rectifier in the frequency converter power supply system, and the output current is the current value of the output side of the inverter in the frequency converter power supply system.

[0087] Calculation module 120 is used to: calculate the DC bus voltage setpoint based on the incoming line voltage and the outgoing line current;

[0088] The input module 130 is used to: input the DC bus voltage setting value into the rectifier so that the rectifier performs closed-loop control according to the DC bus voltage setting value, so that the difference between the DC bus voltage value output by the rectifier and the output voltage of the frequency converter power supply system is kept in dynamic balance.

[0089] In one embodiment, the computing module 120 includes:

[0090] A reference calculation unit is used to obtain the output voltage setting value of the variable frequency power supply system, and calculate the reference DC bus voltage setting value based on the output voltage setting value and the input voltage.

[0091] The compensation calculation unit is used to obtain the preset parameter values ​​on the output side of the frequency converter power supply system, and calculate the voltage compensation value based on the preset parameter values ​​and the output current; wherein, the preset parameter values ​​are the values ​​of the parameters on the output side that affect the output power quality of the frequency converter power supply system;

[0092] The first determining unit is used to determine the DC bus voltage setting value based on the reference DC bus voltage setting value and the voltage compensation value.

[0093] Furthermore, the reference calculation unit is specifically used to: calculate the reference DC bus voltage setting value using a first calculation formula, wherein the first calculation formula is:

[0094] U1=U Lrated *K+ U outsp * K outsp +U Line * K Line

[0095] In the formula, U1 is the reference DC bus voltage setting value, U Lrated U is the rated voltage of the incoming line, K is the rectification factor, and U is the current. outspK is the set value for the output voltage. outsp U is the output voltage influence factor. Line K is the input voltage. Line This is the factor affecting the incoming line voltage.

[0096] Furthermore, the compensation calculation unit is specifically used to: calculate the voltage compensation value using a second calculation formula, wherein the second calculation formula is:

[0097] U2= K Iout *(U Trated *Z Tout *I out / I TIN + I out *Z cable / G+ I out *Z load )

[0098] In the formula, U2 is the voltage compensation value, K Iout U is the influencing factor of outgoing line current. Trated Z is the rated voltage of the low-voltage side of the output transformer in the output side. Tout I is the impedance of the outgoing transformer. Out For the outgoing line current, I TIN Z is the rated current on the low-voltage side of the outgoing transformer. cable Z is the impedance of the output cable on the output side; G is the turns ratio of the output transformer; Z load The impedance of the load on the output side.

[0099] In one embodiment, the first determining unit is specifically configured to: sum the reference DC bus voltage setting value and the voltage compensation value to obtain an initial setting value for the DC bus voltage; determine whether the initial setting value is within a preset range; if so, use the initial setting value as the target setting value.

[0100] Furthermore, the first determining unit is also specifically used to: if the initial setting value is greater than the upper limit of the preset range, then take the upper limit of the preset range as the target setting value.

[0101] Furthermore, the first determining unit is specifically used to: if the initial setting value is less than the lower limit of the preset range, then take the lower limit of the preset range as the target setting value.

[0102] It is understood that explanations, specific implementation methods, beneficial effects, examples, etc. of the contents of the device provided in the embodiments of the present invention can be found in the corresponding parts of the first aspect and the second aspect, and will not be repeated here.

[0103] Thirdly, embodiments of the present invention provide a variable frequency power supply system, see [link to relevant documentation]. Figure 5 The system 200 includes an incoming transformer 210, a rectifier 220, an inverter 230, and an outgoing transformer 240 connected in sequence. The variable frequency power supply system also includes a controller 250, which is connected to a first node A, a second node B, and the rectifier 220. The first node A is the node between the incoming transformer 210 and the rectifier 220, and the second node B is the node between the inverter 230 and the outgoing transformer 240. The controller 250 is a voltage control device 100 provided by the second aspect.

[0104] Understandably, the controller uses the method provided in the first aspect for voltage control.

[0105] The outgoing transformer provides power to the load through the outgoing cable.

[0106] In this controller, the first node obtains the input voltage, the second node obtains the output current, and then calculates the DC bus voltage setpoint. This value is then sent to the rectifier, which performs rectification according to the DC bus voltage setpoint, thus maintaining a dynamic balance between the output DC bus voltage and the output voltage of the entire system.

[0107] It is understood that explanations of relevant content, specific implementation methods, beneficial effects, examples, etc. in the system provided in the embodiments of the present invention can be found in the corresponding parts of the first and second aspects, and will not be repeated here.

[0108] Fourthly, embodiments of the present invention provide a computing device, the device comprising: at least one memory and at least one processor;

[0109] The at least one memory is used to store a machine-readable program;

[0110] The at least one processor is configured to invoke the machine-readable program to execute the method provided in the first aspect.

[0111] It is understood that explanations, specific implementation methods, beneficial effects, examples, etc. of the contents of the device provided in the embodiments of the present invention can be found in the corresponding parts of the method provided in the first aspect, and will not be repeated here.

[0112] Fifthly, embodiments of the present invention provide a computer-readable medium storing computer instructions, which, when executed by a processor, cause the processor to perform the method provided in the first aspect.

[0113] Specifically, a system or apparatus equipped with a storage medium may be provided, on which software program code implementing the functions of any of the embodiments described above is stored, and the computer (or CPU or MPU) of the system or apparatus may read and execute the program code stored in the storage medium.

[0114] In this case, the program code read from the storage medium can itself implement the function of any of the above embodiments, and therefore the program code and the storage medium storing the program code constitute part of the present invention.

[0115] Storage media embodiments for providing program code include floppy disks, hard disks, magneto-optical disks, optical disks (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), magnetic tapes, non-volatile memory cards, and ROMs. Alternatively, program code can be downloaded from a server computer via a communication network.

[0116] Furthermore, it should be clear that not only can the program code read by the computer be executed, but also the operating system or other components operating on the computer can be instructed based on the program code to perform some or all of the actual operations, thereby realizing the function of any of the embodiments described above.

[0117] Furthermore, it is understood that the program code read from the storage medium is written to the memory set in the expansion board inserted into the computer or to the memory set in the expansion module connected to the computer. Then, based on the instructions of the program code, the CPU or other components installed on the expansion board or expansion module execute some and all of the actual operations, thereby realizing the function of any of the above embodiments.

[0118] It is understood that explanations, specific implementation methods, beneficial effects, examples, etc. of the contents in the computer-readable medium provided in the embodiments of the present invention can be found in the corresponding parts of the method provided in the first aspect, and will not be repeated here.

[0119] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the device embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0120] Those skilled in the art will recognize that, in one or more of the examples above, the functions described in this invention can be implemented using hardware, software, widgets, or any combination thereof. When implemented in software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or code on a computer-readable medium.

[0121] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solution of the present invention should be included within the scope of protection of the present invention.

Claims

1. A voltage control method for a variable frequency power supply system, characterized in that, include: Obtain the input voltage and output current of the variable frequency power supply system; wherein, the input voltage is the voltage value of the input side of the rectifier in the variable frequency power supply system, and the output current is the current value of the output side of the inverter in the variable frequency power supply system. Obtain the output voltage setpoint of the variable frequency power supply system, and calculate the reference DC bus voltage setpoint using a first calculation formula based on the output voltage setpoint and the input voltage; the first calculation formula is: U1=U Lrated *K+ U outsp * K outsp + U Line * K Line In the formula, U1 is the reference DC bus voltage setting value, U Lrated U is the rated voltage of the incoming line, K is the rectification factor, and U is the current. outsp K is the output voltage setpoint. outsp U is the output voltage influence factor. Line K is the input voltage. Line The factor affecting the incoming line voltage; Obtain the preset parameter values ​​on the output side of the variable frequency power supply system, and calculate the voltage compensation value based on the preset parameter values ​​and the output current; The DC bus voltage setting value is determined based on the reference DC bus voltage setting value and the voltage compensation value; The DC bus voltage setting value is input to the rectifier so that the rectifier performs closed-loop control according to the DC bus voltage setting value, thereby maintaining a dynamic balance between the DC bus voltage value output by the rectifier and the output voltage of the frequency converter power supply system.

2. The method according to claim 1, characterized in that, The DC bus voltage setting value is a target setting value. Correspondingly, determining the DC bus voltage setting value based on the reference DC bus voltage setting value and the voltage compensation value includes: The initial setting value of the DC bus voltage is obtained by summing the reference DC bus voltage setting value and the voltage compensation value. Determine whether the initial setting value is within the preset range; If so, the initial setting value will be used as the target setting value.

3. The method according to claim 2, characterized in that, Also includes: If the initial setting value is greater than the upper limit of the preset range, then the upper limit of the preset range is used as the target setting value.

4. The method according to claim 2, characterized in that, Also includes: If the initial setting value is less than the lower limit of the preset range, then the lower limit of the preset range is taken as the target setting value.

5. A voltage control device for a variable frequency power supply system, characterized in that, The device (100) includes: The acquisition module (110) is used to: acquire the input voltage and output current of the frequency converter power supply system; wherein, the input voltage is the voltage value of the input side of the rectifier in the frequency converter power supply system, and the output current is the current value of the output side of the inverter in the frequency converter power supply system. Calculation module (120), used for: Obtain the output voltage setpoint of the variable frequency power supply system, and calculate the reference DC bus voltage setpoint using a first calculation formula based on the output voltage setpoint and the input voltage; the first calculation formula is: U1=U Lrated *K+ U outsp * K outsp + U Line * K Line In the formula, U1 is the reference DC bus voltage setting value, U Lrated U is the rated voltage of the incoming line, K is the rectification factor, and U is the current. outsp K is the output voltage setpoint. outsp U is the output voltage influence factor. Line K is the input voltage. Line The factor affecting the incoming line voltage; Obtain the preset parameter values ​​on the output side of the variable frequency power supply system, and calculate the voltage compensation value based on the preset parameter values ​​and the output current; The DC bus voltage setting value is determined based on the reference DC bus voltage setting value and the voltage compensation value; The input module (130) is used to: input the DC bus voltage setting value to the rectifier so that the rectifier performs closed-loop control according to the DC bus voltage setting value, so that the difference between the DC bus voltage value output by the rectifier and the output voltage of the frequency converter power supply system is kept in dynamic balance.

6. A variable frequency power supply system, characterized in that, The system (200) includes an incoming transformer (210), a rectifier (220), an inverter (230), and an outgoing transformer (240) connected in sequence. The variable frequency power supply system also includes a controller (250), which is connected to a first node (A), a second node (B), and the rectifier (220). The first node (A) is the node between the incoming transformer (210) and the rectifier (220), and the second node (B) is the node between the inverter (230) and the outgoing transformer (240). The controller (250) is the voltage control device (100) as described in claim 5.

7. A computing device, characterized in that, The device includes: at least one memory and at least one processor; The at least one memory is used to store a machine-readable program; The at least one processor is configured to invoke the machine-readable program to execute the method according to any one of claims 1 to 4.

8. A computer-readable medium, characterized in that, The computer-readable medium stores computer instructions that, when executed by a processor, cause the processor to perform the method described in any one of claims 1 to 4.

Images