Method, device and equipment for controlling back-to-back converter and storage medium

Abstract

The invention provides a method and device for controlling a back-to-back converter, equipment and a storage medium, and belongs to the technical field of power electronics. The method comprises the steps that in the working process of the back-to-back converter, the input voltage and the input current of a rectifier in the back-to-back converter are acquired; determining a target reference voltage value of a direct current bus in the back-to-back converter based on the input voltage and the input current; and controlling a switching tube in the rectifier based on the target reference voltage value. By adopting the scheme, the on-state loss of the switch tube in the rectifier in a light load state is reduced, the stress of the switch tube in the rectifier in a heavy load state is reduced, and the working efficiency and the working reliability of the whole back-to-back converter are improved.

Description

Technical Field

[0001] The present disclosure relates to the field of power electronics technology, and in particular to a method, device, equipment and storage medium for controlling a back-to-back converter. Background Art

[0002] A back-to-back converter is a circuit topology that can convert AC power and DC power, and is often used in equipment such as UPS (uninterruptible power supply) and frequency converters.

[0003] The back-to-back converter includes a rectifier, an inverter, and a DC bus. The rectifier is used to access the power grid, convert the AC power input from the power grid into DC power and transmit it to the DC bus, and the inverter is used to convert the DC power in the DC bus into AC power again and transmit it to the load. The rectifier and the inverter each include a plurality of switch tubes, which can realize the conversion between AC power and DC power by controlling the working state of the switch tubes in the rectifier and the inverter respectively.

[0004] In the related art, during the operation of the back-to-back converter, the voltage across the DC bus is constant. Under constant voltage, when the load power changes, the current flowing through the anti-parallel diode in the back-to-back converter will increase, which will increase the conduction loss of the switch tube, and when the power is large, the device voltage stress is large, which is prone to overvoltage breakdown and large dv / dt, thereby reducing the working efficiency and working reliability of the entire back-to-back converter. Summary of the invention

[0005] The embodiments of the present disclosure provide a method, device, equipment and storage medium for controlling a back-to-back converter, which can solve the problem in the related art that under constant voltage, the increase in load power aggravates the on-state loss of the switch tube, as well as high device voltage stress and dv / dt, thereby reducing the working efficiency and working reliability of the back-to-back converter. The technical solution is as follows:

[0006] In a first aspect, the present disclosure provides a method for controlling a back-to-back converter, the method comprising:

[0007] During the operation of the back-to-back converter, obtaining an input voltage and an input current of a rectifier in the back-to-back converter;

[0008] Determining a target reference voltage value of a DC bus in the back-to-back converter based on the input voltage and the input current;

[0009] The switch tube in the rectifier is controlled based on the target reference voltage value.

[0010] In a possible implementation, determining a target reference voltage value of a DC bus in the back-to-back converter based on the input voltage and the input current includes:

[0011] Determining a voltage change of the DC bus based on a phase of the input voltage and a phase of the input current;

[0012] Obtaining an initial setting value of the voltage of the DC bus;

[0013] A target reference voltage value of the DC bus is determined based on an initial setting value of the voltage of the DC bus and the voltage variation.

[0014] In a possible implementation, when the input current is greater than or equal to a first preset current threshold, the method further includes:

[0015] Based on a relationship function between a reference voltage value for controlling a rectifier and a stress value of a switching device in the back-to-back converter, a target reference voltage value of the DC bus corresponding to the input current is determined.

[0016] In a possible implementation, determining the target reference voltage value of the DC bus corresponding to the input current based on a relationship function between a reference voltage value for controlling a rectifier and a stress value of a switching device in the back-to-back converter includes:

[0017] Based on the current stress value of the switch tube, the maximum reference voltage value of the DC bus is reduced to obtain the target reference voltage value, wherein the reduced value is positively correlated with the stress value.

[0018] In a possible implementation, the reducing the maximum reference voltage value of the DC bus based on the current stress value of the switch tube to obtain the target reference voltage value includes:

[0019] Based on the formula V dcset =V dcmax -G c1 (V spike -V spikesafe ) determines the target reference voltage value, where V dcset is the target reference voltage value, V dcmax is the maximum reference voltage value, G c1 For the first voltage regulator controller, V spike is the current stress value of the switch tube, V spikesafe is the safety stress value of the switch tube.

[0020] In a possible implementation, determining the target reference voltage value of the DC bus corresponding to the input current based on a relationship function between a reference voltage value for controlling a rectifier and a stress value of a switching device in the back-to-back converter includes:

[0021] When the input current is less than or equal to the second current threshold, based on the current stress value of the switch tube, the maximum reference voltage value is reduced to obtain the target reference voltage value, wherein the reduced value is positively correlated with the stress value;

[0022] When the input current is greater than the second current threshold, the target reference voltage value is determined to be a specified minimum reference voltage value.

[0023] In a possible implementation, the reducing the maximum reference voltage value based on the current stress value of the switch tube to obtain the target reference voltage value includes:

[0024] Based on the formula V dcset =V dcmax -G c2 (V spike -V spikesafe ) determines the target reference voltage value, where V dcset is the target reference voltage value, V dcmax is the preset maximum reference voltage value, G c2 For the second voltage regulator controller, V spike is the current stress value of the switch tube, V spikesafe is the safety stress value of the switch tube.

[0025] In a second aspect, the present disclosure provides a device for controlling a back-to-back converter, the device comprising:

[0026] An acquisition module is used to acquire the input voltage and input current of the rectifier in the back-to-back converter during the operation of the back-to-back converter:

[0027] A determination module, configured to determine a target reference voltage value of a DC bus in the back-to-back converter based on the input voltage and the input current;

[0028] A control module is used to control the switch tube in the rectifier based on the target reference voltage value.

[0029] In a possible implementation manner, the determining module is used to:

[0030] Determining a voltage change of the DC bus based on a phase of the input voltage and a phase of the input current;

[0031] Obtaining an initial setting value of the voltage of the DC bus;

[0032] A target reference voltage value of the DC bus is determined based on an initial setting value of the voltage of the DC bus and the voltage variation.

[0033] In a possible implementation, when the input current is greater than or equal to a first preset current threshold, the determining module is further configured to:

[0034] Based on a relationship function between a reference voltage value for controlling a rectifier and a stress value of a switching device in the back-to-back converter, a target reference voltage value of the DC bus corresponding to the input current is determined.

[0035] In a possible implementation manner, the determining module is used to:

[0036] Based on the current stress value of the switch tube, the maximum reference voltage value of the DC bus is reduced to obtain the target reference voltage value, wherein the reduced value is positively correlated with the stress value.

[0037] In a possible implementation manner, the determining module is used to:

[0038] Based on the formula V dcset =V dcmax -G c1 (V spike -V spikesafe ) determines the target reference voltage value, where V dcset is the target reference voltage value, V dcmax is the maximum reference voltage value, G c1 For the first voltage regulator controller, V spike is the current stress value of the switch tube, V spikesafe is the safety stress value of the switch tube.

[0039] In a possible implementation manner, the determining module is used to:

[0040] When the input current is less than or equal to the second current threshold, based on the current stress value of the switch tube, the maximum reference voltage value is reduced to obtain the target reference voltage value, wherein the reduced value is positively correlated with the stress value;

[0041] When the input current is greater than the second current threshold, the target reference voltage value is determined to be a specified minimum reference voltage value.

[0042] In a possible implementation manner, the determining module is used to:

[0043] Based on the formula V dcset =Vdcmax -G c2 (V spike -V spikesafe ) determines the target reference voltage value, where V dcset is the target reference voltage value, V dcmax is the preset maximum reference voltage value, G c2 For the second voltage regulator controller, V spike is the current stress value of the switch tube, V spikesafe is the safety stress value of the switch tube.

[0044] In a third aspect, the present disclosure provides an electronic device, comprising a processor and a memory, wherein the memory stores at least one instruction, and the instruction is loaded and executed by the processor to implement the operations performed by the method for controlling a back-to-back converter.

[0045] In a fourth aspect, the present disclosure provides a computer-readable storage medium, wherein at least one instruction is stored in the storage medium, and the instruction is loaded and executed by a processor to implement the operations performed by the method for controlling a back-to-back converter.

[0046] The technical solution provided by the embodiments of the present disclosure has the following beneficial effects:

[0047] In the scheme provided by the embodiment of the present disclosure, the target reference voltage value of the DC bus can be determined based on the input current and input voltage of the rectifier, and the target reference voltage value is also the expected output voltage of the rectifier. With this scheme, during the operation of the back-to-back converter, when the current or power of the load changes, the expected output voltage of the rectifier can be adjusted, that is, the voltage at both ends of the DC bus can be adjusted, which can reduce the conduction loss of the switch tube in the rectifier under light load conditions, reduce the stress of the switch tube in the rectifier under heavy load conditions and the dv / dt at the turn-off time, which is conducive to improving the working efficiency and working reliability of the entire back-to-back converter.

[0048] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0050] Figure 1 It is a structural schematic diagram of a back-to-back converter in the related art;

[0051] Figure 2 It is a structural schematic diagram of a back-to-back converter in the related art;

[0052] Figure 3 is a flow chart of a method for controlling a back-to-back converter provided by an embodiment of the present disclosure;

[0053] Figure 4 is a phase diagram of voltage and current provided by an embodiment of the present disclosure;

[0054] Figure 5 is a flow chart of controlling a switch tube provided by an embodiment of the present disclosure;

[0055] Figure 6 is a schematic diagram of a relationship function between a reference voltage value and a current provided by an embodiment of the present disclosure;

[0056] Figure 7 is a schematic diagram of a relationship function between a reference voltage value and a current provided by an embodiment of the present disclosure;

[0057] Figure 8 is a structural schematic diagram of a device for controlling a back-to-back converter provided by an embodiment of the present disclosure;

[0058] Fig. 9 It is a structural schematic diagram of an electronic device provided by the present disclosure. DETAILED DESCRIPTION

[0059] Unless otherwise defined, the technical terms or scientific terms used herein shall have the usual meanings understood by persons with ordinary skills in the field to which the present disclosure belongs. The words "first", "second", "third" and similar words used in the patent application specification and claims of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not indicate a quantity limitation, but indicate the existence of at least one. Words such as "include" or "comprise" and similar words mean that the elements or objects appearing before "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. Words such as "connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0060] First, a brief description of the back-to-back converter is given.

[0061] A back-to-back converter generally refers to a three-phase back-to-back converter, which is a circuit topology that can convert AC and DC power. It is often used in UPS (uninterruptible power supply), inverters and other equipment. Figure 1 is a schematic diagram of a back-to-back converter in the related art. As an example, Figure 1 As shown, the back-to-back converter generally includes a rectifier, an inverter and a DC bus, and there is at least one bus capacitor in the DC bus.

[0062] The rectifier is used to access the power grid, convert the AC power input from the power grid into DC power, and transmit the converted DC power to the DC bus. The inverter is used to convert the DC power in the DC bus into AC power again and transmit it to the load. The rectifier and inverter each include multiple switch tubes, which can realize the conversion between AC power and DC power by controlling the working state of the switch tubes in the rectifier and inverter respectively.

[0063] Optionally, the back-to-back converter may include two filters in addition to the rectifier, the inverter and the DC bus. One filter is connected in series between the power grid and the rectifier, and the other filter is connected in series between the inverter and the load. The specific composition of the back-to-back converter is not limited here.

[0064] Figure 2 is a schematic diagram of a back-to-back converter in the related art. As an example, Figure 2 As shown in FIG. 1 , the backrest converter includes a rectifier, an inverter, a DC bus and two filters. The rectifier includes 6 switch tubes, namely S 1A1 , S 1A2 , S 1B1 , S 1B2 , S 1C1 and S 1C2 , where S 1A1 and S 1A2 A pair of switch tubes, S 1B1 and S 1B2 A pair of switch tubes, S 1C1 and S 1C2 is a pair of switch tubes. The inverter includes 6 switch tubes, namely S 2A1 , S 2A2 , S 2B1 , S 2B2 , S 2C1 and S 2C2 , where S 2A1 and S 2A2 A pair of switch tubes, S 2B1 and S 2B2 A pair of switch tubes, S 2C1 and S2C2 A pair of switch tubes. In any pair of switch tubes in a rectifier or inverter, the two switch tubes will not be closed at the same time.

[0065] The circuit topology of rectifiers and inverters is not limited to Figure 2 The three-phase six-switch topology shown in FIG. 1 , three-level NPC (neutral point clamped) and three-level ANPC (active neutral point clamped) topologies are also applicable. No limitation is imposed on the circuit structure of the rectifier and the inverter.

[0066] Among them, the closing and opening of the switch tube in the rectifier can be controlled by the rectifier control unit. It should be noted that the rectifier control unit can be considered as a control unit in the control program corresponding to the back-to-back converter, not physical hardware. In addition, the control program can be run on any electronic device with a processor, memory and other components, and the electronic device can control the back-to-back converter. For example, the electronic device can be an MCU (microcontroller unit) that controls the back-to-back converter.

[0067] In the related art, during the operation of the back-to-back converter, the voltage across the DC bus is constant. Under constant voltage, when the power of the load changes (such as the power of the motor changes), the current flowing through the switch tube in the back-to-back converter will change, which will increase the switching loss and conduction loss of the switch tube, thereby reducing the working efficiency and working reliability of the entire back-to-back converter.

[0068] The embodiments of the present disclosure provide a method, device, equipment and storage medium for controlling a back-to-back converter, which can solve the problem in the related art that under constant voltage, the on-state loss of the switch tube is aggravated due to the increase of load power, and the voltage stress of the switch device and the dv / dt at turn-off are increased under heavy load, thereby reducing the working efficiency and working reliability of the back-to-back converter. In order to make the purpose, technical solution and advantages of the present disclosure clearer, the embodiments of the present disclosure will be further described in detail in conjunction with the accompanying drawings.

[0069] Figure 3 is a flow chart of a method for controlling a back-to-back converter provided by an embodiment of the present disclosure. As described above, in addition to the above-mentioned rectifier control unit, a voltage regulation control unit may also be included in the software program for controlling the back-to-back converter. The voltage regulation control unit is the execution subject of the method provided by the embodiment of the present disclosure. As an example, Figure 3 As shown, a method for controlling a back-to-back converter provided by an embodiment of the present disclosure may include the following processing steps.

[0070] S301. During the operation of the back-to-back converter, an input voltage and an input current of a rectifier in the back-to-back converter are obtained.

[0071] The input voltage and input current of the rectifier can be obtained by sampling, or by combining the current parameter values ​​on both sides of the back-to-back converter and the switch control signals corresponding to the rectifier and the inverter. The specific details belong to the prior art and will not be described here.

[0072] S302: Determine a target reference voltage value of a DC bus in a back-to-back converter based on an input voltage and an input current.

[0073] In some examples, the technician can first determine the voltage change of the DC bus based on the phase of the input voltage and the phase of the input current. Then, the technician can further obtain the current initial voltage setting value of the DC bus in the back-to-back converter. Finally, the technician can determine the target reference voltage value of the DC bus based on the current initial voltage setting value of the DC bus and the above voltage change.

[0074] As an example, Figure 4 is a phase diagram of voltage and current provided by an embodiment of the present disclosure. Figure 4 As shown, when the rectifier input current i g and input voltage v A lie in Figure 4 In the first half of the cycle shown in the figure, the initial setting value of the DC bus voltage needs to be increased, that is, the initial setting value of the DC bus voltage V dc0 On the basis of increasing the voltage change ΔV; when the rectifier input current i g and input voltage v A lie in Figure 4 In the second half of the cycle shown in FIG. 1 , the initial setting value of the DC bus voltage needs to be reduced, that is, the initial setting value of the DC bus voltage V dc0 On the basis of this, the voltage change ΔV is reduced.

[0075] As an example, the calculation formula of the voltage change ΔV can be as follows:

[0076]

[0077] Where ΔV is the voltage change; V dcmax is the maximum operating voltage; V dc0 is the initial voltage setting value; V dcmin is the minimum operating voltage.

[0078] S303: Control the switch tube in the rectifier based on the target reference voltage value.

[0079] After the voltage regulation control unit determines the target reference voltage value, it can control each switch tube in the rectifier together with the rectifier control unit to make the output voltage of the rectifier reach the target reference voltage. Figure 5 is a flow chart of controlling a switch tube provided by an embodiment of the present disclosure. As an example, Figure 5 As shown, the control process of the switch tube can be as follows:

[0080] First, the rectifier control unit obtains the AC parameters (such as the voltage effective value V 1ABC And the effective value of current I 1ABC ), and obtain the target reference voltage value V sent by the voltage regulation control unit according to the fixed period dcset .

[0081] Then, the rectifier control unit outputs the modulation wave M corresponding to different switch tubes in the rectifier based on the AC power parameters and the target reference voltage value. 1ABC .

[0082] Then, the rectifier control unit obtains the modulation wave M corresponding to each switch tube in the rectifier. 1ABC After that, the modulation wave M corresponding to each switch tube can be 1ABC Input to the modulation unit, through the modulation unit to each switch tube corresponding to the modulation wave M 1ABC With the preset switching frequency f s The carrier is modulated to output the control signal S corresponding to each switch tube 1ABC .

[0083] Finally, the rectifier control unit can be controlled according to the control signal S 1ABC Control the closing and opening of the switch tube in the rectifier. For example, the control signal S 1ABC Separate control Figure 2 S 1A1 , S 1A2 , S 1B1 , S 1B2 , S 1C1 and S 1C2 closing and opening, etc.

[0084] Optionally, the voltage regulating control unit may be considered as a part of the rectifier control unit. This case is the same as the case where the voltage regulating control unit is independent of the rectifier control unit, and is not described in detail here.

[0085] In the scheme provided by the embodiment of the present disclosure, the target reference voltage value of the DC bus can be determined based on the input current and input voltage of the rectifier, and the target reference voltage value is also the expected output voltage of the rectifier. With this scheme, during the operation of the back-to-back converter, when the current or power of the load changes, the expected output voltage of the rectifier can be adjusted, that is, the voltage at both ends of the DC bus can be adjusted, which can reduce the conduction loss of the switch tube in the rectifier under light load conditions, reduce the stress of the switch tube in the rectifier under heavy load conditions and the dv / dt at the turn-off time, which is conducive to improving the working efficiency and working reliability of the entire back-to-back converter.

[0086] In some examples, the technicians pre-establish a relationship function between the reference voltage value for controlling the rectifier and the stress value of the switch device in the back-to-back converter in the voltage regulation control unit. When the input current of the rectifier is less than the first preset current threshold, the target reference voltage value of the DC bus can be determined by the above step S302, and when the input current is greater than or equal to the first preset current threshold, the target reference voltage value of the DC bus corresponding to the input current can be determined according to the preset relationship function. The two relationship functions provided by the present disclosure are described below.

[0087] Relationship Function 1

[0088] The voltage regulation control unit obtains the input current of the rectifier (i.e. Figure 6 After i1 or i2 shown in FIG. 1 is reached, it is necessary to determine whether the input current is equal to the first current threshold (i.e. Figure 6 The i shown in T ), wherein the first current threshold can be preset by a technician based on experience, and no limitation is made here for the first parameter threshold.

[0089] When the input current of the above rectifier is greater than or equal to the first current threshold, it is necessary to further determine the maximum reference voltage value of the DC bus, wherein the maximum reference voltage value can be preset by the technician based on experience, and no limitation is imposed on the maximum reference voltage value. Then, based on the current stress value of the switch tube in the back-to-back converter, the maximum reference voltage value is reduced to obtain the target reference voltage value of the DC bus, wherein the reduced value is positively correlated with the stress value, that is, the larger the stress value, the larger the reduced value.

[0090] Figure 6 is a schematic diagram of a relationship function between a reference voltage value and a current provided by an embodiment of the present disclosure. As an example, Figure 6 As shown, the expression of the relationship function between the reference voltage value and the current can be as follows:

[0091] V dcset =V dcmax -Gc1 (V spike -V sp i kesafe ) (2)

[0092] Among them, V dcset is the target reference voltage value, V dcmax is the maximum reference voltage value, G c1 For the first voltage regulator controller, V spike is the current stress value of the switch tube, V spikesafe is the safety stress value of the switch tube.

[0093] It should be noted that the first voltage regulator controller G c1 A proportional controller, a proportional integral controller, etc. may be used. In some examples, the first voltage regulator controller G c1 is a proportional controller (i.e., proportional control law), and the basic expression of the proportional control law is P(t) = K p e(t), where K p is the proportional magnification coefficient, and t is V in the above relationship function expression. spike -V spikesafe In some other examples, the first voltage regulator controller G c1 It is a proportional-integral controller (i.e., proportional-integral control law). The basic expression of the proportional-integral control law is P(t)=K p (e(t)+K i ∫e(t)dt), where K p is the proportional magnification factor, K i is the integral proportional coefficient, and t is V in the above relationship function expression. spike -V spikesafe No limitation is imposed on other aspects of the first voltage regulating controller.

[0094] Optionally, the technician may also preset a first power threshold. When the current power of the rectifier is less than the first power threshold, the target reference voltage is determined using the method in step S302. When the current power of the rectifier is greater than or equal to the first power threshold, the target reference voltage is determined using the method mentioned in the above relationship function 1. The specific steps are not repeated here.

[0095] Relationship Function 2

[0096] After the voltage regulation control unit obtains the input current of the rectifier, it is necessary to determine the current input current (i.e. Figure 7 i1 or i2 shown in FIG. 1 and a preset first current threshold value (i.e. Figure 7 The i shown in T1 ), the second current threshold (i.e. Figure 7 The i shown in T2), wherein the first current threshold and the second current threshold can be preset by technicians based on experience. The second current threshold is different from the first current threshold only in numerical value, and the second current threshold is greater than the first current threshold. Therefore, the second current threshold is not described in detail here.

[0097] When the current current of the DC bus is greater than or equal to the first current threshold and less than or equal to the second current threshold, it is necessary to further determine the maximum reference voltage value of the DC bus, and then, based on the current stress value of the switching tube, reduce the maximum reference voltage value to obtain the target reference voltage value, wherein the reduced value is positively correlated with the stress value.

[0098] When the DC bus target current is greater than the first current threshold and less than or equal to the second current threshold, the target reference voltage value is determined to be a specified minimum reference voltage value.

[0099] Figure 7 is a schematic diagram of a relationship function between a reference voltage value and a current provided by an embodiment of the present disclosure. As an example, Figure 7 As shown, the expression of the relationship function between the reference voltage value and the current can be as follows:

[0100]

[0101] Among them, V dcset is the target reference voltage value mentioned above, V dcmax is the maximum reference voltage value specified above, i is the current value of the DC bus, i T1 is the first current threshold, i T2 is the second current threshold, i max is the maximum current threshold, G c2 For the second voltage regulator controller, V spike is the current stress value of the switch tube, V spikesafe is the safety stress value of the switch tube, V dcmin is the minimum reference voltage value specified above. Figure 7 As shown, when the current value of the DC bus is equal to i T2 When the target reference voltage is the specified minimum reference voltage value V dcmin .

[0102] It should be noted that i max It can be the maximum current threshold determined by technicians based on multiple experiments.

[0103] It should be noted that the second voltage regulator controller G c2Proportional controller, proportional integral controller, etc. can be used. The second voltage regulating controller is different from the first voltage regulating controller only in parameter selection, so the second voltage regulating controller is not described here.

[0104] With this solution, when the current current of the DC bus exceeds the first current threshold, it indicates that the back-to-back converter is in a heavy load state. At this time, lowering the voltage across the DC bus is conducive to reducing the ripple current of the DC bus capacitor, and at the same time, it is conducive to reducing common-mode interference and the voltage stress of the switching device, and reducing the size and cost of the EMI filter. Moreover, reducing the ripple current of the DC bus capacitor under heavy load is conducive to reducing the loss of the DC bus capacitor and increasing its service life. In addition, it is conducive to keeping the voltage stress of the switch tube within a reliable operating range, avoiding the breakdown of the switch tube, and reducing the insulation pressure on the load side.

[0105] Optionally, the technician may also preset a first power threshold and a second power threshold, wherein the second power threshold is greater than the first power threshold. When the current power of the rectifier is less than the first power threshold, the target reference voltage is determined by the method in step S302. When the current power of the rectifier is greater than or equal to the first power threshold and less than or equal to the second power threshold, the formula V mentioned in the above relationship function 2 is used. dcset =V dcmax -G c2 (V spike -V spikesafe ) determine the target reference voltage. When the current power of the rectifier is greater than the first power threshold and less than or equal to the second power threshold, determine the target reference voltage value as a specified minimum reference voltage value. The specific steps are not repeated here.

[0106] In the scheme provided by the embodiment of the present disclosure, the target reference voltage value of the DC bus can be determined based on the input current and input voltage of the rectifier, and the target reference voltage value is also the expected output voltage of the rectifier. With this scheme, during the operation of the back-to-back converter, when the current or power of the load changes, the expected output voltage of the rectifier can be adjusted, that is, the voltage at both ends of the DC bus can be adjusted, which can reduce the conduction loss of the switch tube in the rectifier under light load conditions, reduce the stress of the switch tube in the rectifier under heavy load conditions, and reduce the loss of the DC bus capacitor to increase its service life, thereby helping to improve the working efficiency and reliability of the entire back-to-back converter.

[0107] Based on the same technical concept, the present disclosure provides a device for controlling a back-to-back converter. Figure 8 is a schematic diagram of a structure of a device for controlling a back-to-back converter provided by an embodiment of the present disclosure. As an example, Figure 8 As shown, the device includes an acquisition module 810 , a determination module 820 and a control module 830 .

[0108] An acquisition module 810, configured to acquire an input voltage and an input current of a rectifier in the back-to-back converter during operation of the back-to-back converter;

[0109] A determination module 820, configured to determine a target reference voltage value of a DC bus in the back-to-back converter based on the input voltage and the input current;

[0110] The control module 830 is used to control the switch tube in the rectifier based on the target reference voltage value.

[0111] In a possible implementation, the determining module 820 is configured to:

[0112] Determining a voltage change of the DC bus based on a phase of the input voltage and a phase of the input current;

[0113] Obtaining an initial setting value of the voltage of the DC bus;

[0114] A target reference voltage value of the DC bus is determined based on an initial setting value of the voltage of the DC bus and the voltage variation.

[0115] In a possible implementation, when the input current is greater than or equal to a first preset current threshold, the determining module 820 is configured to:

[0116] Based on a relationship function between a reference voltage value for controlling a rectifier and a stress value of a switching device in the back-to-back converter, a target reference voltage value of the DC bus corresponding to the input current is determined.

[0117] In a possible implementation, the determining module 820 is configured to:

[0118] Based on the current stress value of the switch tube, the maximum reference voltage value of the DC bus is reduced to obtain the target reference voltage value, wherein the reduced value is positively correlated with the stress value.

[0119] In a possible implementation, the determining module 820 is configured to:

[0120] Based on the formula V dcset =V dcmax -G c1 (V spike -V spikesafe ) determines the target reference voltage value, where V dcset is the target reference voltage value, V dcmax is the maximum reference voltage value, G c1 For the first voltage regulator controller, V spikeis the current stress value of the switch tube, V spikesafe is the safety stress value of the switch tube.

[0121] In a possible implementation, the determining module 820 is configured to:

[0122] When the input current is less than or equal to the second current threshold, based on the current stress value of the switch tube, the maximum reference voltage value is reduced to obtain the target reference voltage value, wherein the reduced value is positively correlated with the stress value;

[0123] When the input current is greater than the second current threshold, the target reference voltage value is determined to be a specified minimum reference voltage value.

[0124] In a possible implementation, the determining module 820 is configured to:

[0125] Based on the formula V dcset =V dcmax -G c2 (V spike -V spikesafe ) determines the target reference voltage value, where V dcset is the target reference voltage value, V dcmax is the preset maximum reference voltage value, G c2 For the second voltage regulator controller, V spike is the current stress value of the switch tube, V spikesafe is the safety stress value of the switch tube.

[0126] In the scheme provided by the embodiment of the present disclosure, the target reference voltage value of the DC bus can be determined based on the input current and input voltage of the rectifier, and the target reference voltage value is also the expected output voltage of the rectifier. With this scheme, during the operation of the back-to-back converter, when the current or power of the load changes, the expected output voltage of the rectifier can be adjusted, that is, the voltage at both ends of the DC bus can be adjusted, which can reduce the conduction loss of the switch tube in the rectifier under light load conditions, reduce the stress of the switch tube in the rectifier under heavy load conditions, and reduce the loss of the DC bus capacitor to increase its service life, thereby helping to improve the working efficiency and reliability of the entire back-to-back converter.

[0127] It should be noted that: the device for controlling a back-to-back converter provided in the above embodiment only uses the division of the above functional modules as an example when controlling the back-to-back converter. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the electronic device is divided into different functional modules to complete all or part of the functions described above. In addition, the device for controlling a back-to-back converter provided in the above embodiment and the method embodiment for controlling a back-to-back converter belong to the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here.

[0128] Fig. 9 1 is a schematic diagram of the structure of an electronic device provided by the present disclosure. The electronic device may be an MCU (microcontroller unit) for controlling a back-to-back converter. In other possible cases, the electronic device 900 may also be a portable mobile terminal, such as a smart phone, a tablet computer, an MP3 player (moving picture experts group audio layer III), an MP4 (moving picture experts group audio layer IV), a laptop computer or a desktop computer. The electronic device 900 may also be called a user device, a portable terminal, a laptop terminal, a desktop terminal or other names.

[0129] Typically, the electronic device 900 includes a processor 901 and a memory 902 .

[0130] The processor 901 may include one or more processing cores, such as a 4-core processor, a 9-core processor, etc. The processor 901 may be implemented in at least one hardware form of DSP (digital signal processing), FPGA (field-programmable gate array), and PLA (programmable logic array). The processor 901 may also include a main processor and a coprocessor. The main processor is a processor for processing data in the awake state, also known as a CPU (central processing unit); the coprocessor is a low-power processor for processing data in the standby state. In some embodiments, the processor 901 may be integrated with a GPU (graphics processing unit), which is responsible for rendering and drawing the content to be displayed on the display screen. In some embodiments, the processor 901 may also include an AI (artificial intelligence) processor, which is used to process computing operations related to machine learning.

[0131] The memory 902 may include one or more computer-readable storage media, which may be non-transitory. The memory 902 may also include a high-speed random access memory, and a non-volatile memory, such as one or more disk storage devices, flash memory storage devices. In some embodiments, the non-transitory computer-readable storage medium in the memory 902 is used to store at least one instruction, which is used to be executed by the processor 901 to implement the back-to-back converter control method provided by the method embodiment of the present disclosure.

[0132] In some embodiments, the electronic device 900 may further optionally include: a peripheral device interface 903 and at least one peripheral device. The processor 901, the memory 902 and the peripheral device interface 903 may be connected via a bus or a signal line. Each peripheral device may be connected to the peripheral device interface 903 via a bus, a signal line or a circuit board. Specifically, the peripheral device includes: at least one of a radio frequency circuit 904, a display screen 905, a camera assembly 906, an audio circuit 907, a positioning assembly 909 and a power supply 909.

[0133] The peripheral device interface 903 may be used to connect at least one peripheral device related to I / O (input / output) to the processor 901 and the memory 902. In some embodiments, the processor 901, the memory 902, and the peripheral device interface 903 are integrated on the same chip or circuit board; in some other embodiments, any one or two of the processor 901, the memory 902, and the peripheral device interface 903 may be implemented on a separate chip or circuit board, which is not limited in this embodiment.

[0134] The radio frequency circuit 904 is used to receive and transmit RF (radio frequency) signals, also known as electromagnetic signals. The radio frequency circuit 904 communicates with the communication network and other communication devices through electromagnetic signals. The radio frequency circuit 904 converts electrical signals into electromagnetic signals for transmission, or converts received electromagnetic signals into electrical signals. Optionally, the radio frequency circuit 904 includes: an antenna system, an RF transceiver, one or more amplifiers, a tuner, an oscillator, a digital signal processor, a codec chipset, a user identity module card, etc. The radio frequency circuit 904 can communicate with other terminals through at least one wireless communication protocol. The wireless communication protocol includes but is not limited to: the World Wide Web, a metropolitan area network, an intranet, various generations of mobile communication networks (2G, 3G, 4G and 5G), a wireless local area network and / or a WiFi (wireless fidelity) network. In some embodiments, the radio frequency circuit 904 may also include circuits related to NFC (near field communication), which is not limited in the present disclosure.

[0135] The display screen 905 is used to display a UI (user interface). The UI may include graphics, text, icons, videos, and any combination thereof. When the display screen 905 is a touch display screen, the display screen 905 also has the ability to collect touch signals on the surface or above the surface of the display screen 905. The touch signal may be input as a control signal to the processor 901 for processing. At this time, the display screen 905 may also be used to provide virtual buttons and / or virtual keyboards, also known as soft buttons and / or soft keyboards. In some embodiments, the display screen 905 may be one, arranged on the front panel of the electronic device 900; in other embodiments, the display screen 905 may be at least two, arranged on different surfaces of the electronic device 900 or in a folding design; in other embodiments, the display screen 905 may be a flexible display screen, arranged on a curved surface or a folding surface of the electronic device 900. Even, the display screen 905 may be arranged in a non-rectangular irregular shape, i.e., a special-shaped screen. The display screen 905 may be made of materials such as LCD (liquid crystal display), OLED (organic light-emitting diode), etc.

[0136] The camera assembly 906 is used to capture images or videos. Optionally, the camera assembly 906 includes a front camera and a rear camera. Typically, the front camera is arranged on the front panel of the terminal, and the rear camera is arranged on the back of the terminal. In some embodiments, there are at least two rear cameras, which are any one of a main camera, a depth of field camera, a wide-angle camera, and a telephoto camera, so as to realize the fusion of the main camera and the depth of field camera to realize the background blur function, the fusion of the main camera and the wide-angle camera to realize the panoramic shooting and VR (virtual reality) shooting function or other fusion shooting functions. In some embodiments, the camera assembly 906 may also include a flash. The flash can be a monochrome temperature flash or a dual-color temperature flash. A dual-color temperature flash refers to a combination of a warm light flash and a cold light flash, which can be used for light compensation at different color temperatures.

[0137] The audio circuit 907 may include a microphone and a speaker. The microphone is used to collect sound waves from the user and the environment, and convert the sound waves into electrical signals and input them into the processor 901 for processing, or input them into the radio frequency circuit 904 to achieve voice communication. For the purpose of stereo acquisition or noise reduction, there may be multiple microphones, which are respectively arranged at different parts of the electronic device 900. The microphone may also be an array microphone or an omnidirectional acquisition microphone. The speaker is used to convert the electrical signal from the processor 901 or the radio frequency circuit 904 into sound waves. The speaker may be a traditional film speaker or a piezoelectric ceramic speaker. When the speaker is a piezoelectric ceramic speaker, it can not only convert the electrical signal into sound waves audible to humans, but also convert the electrical signal into sound waves inaudible to humans for purposes such as ranging. In some embodiments, the audio circuit 907 may also include a headphone jack.

[0138] The positioning component 908 is used to locate the current geographical location of the electronic device 900 to implement navigation or LBS (location based service). The positioning component 908 can be a positioning component based on GPS (global positioning system), Beidou system or Galileo system.

[0139] The power supply 909 is used to power various components in the electronic device 900. The power supply 909 can be an alternating current, a direct current, a disposable battery, or a rechargeable battery. When the power supply 909 includes a rechargeable battery, the rechargeable battery can be a wired rechargeable battery or a wireless rechargeable battery. A wired rechargeable battery is a battery charged through a wired line, and a wireless rechargeable battery is a battery charged through a wireless coil. The rechargeable battery can also be used to support fast charging technology.

[0140] In some embodiments, the electronic device 900 further includes one or more sensors 910 , including but not limited to: an acceleration sensor 911 , a gyroscope sensor 912 , a pressure sensor 913 , a fingerprint sensor 914 , an optical sensor 915 , and a proximity sensor 916 .

[0141] The acceleration sensor 911 can detect the magnitude of acceleration on the three coordinate axes of the coordinate system established by the electronic device 900. For example, the acceleration sensor 911 can be used to detect the components of gravity acceleration on the three coordinate axes. The processor 901 can control the display screen 905 to display the user interface in a horizontal view or a vertical view according to the gravity acceleration signal collected by the acceleration sensor 911. The acceleration sensor 911 can also be used for collecting game or user motion data.

[0142] The gyro sensor 912 can detect the body direction and rotation angle of the electronic device 900, and the gyro sensor 912 can cooperate with the acceleration sensor 911 to collect the user's 3D actions on the electronic device 900. The processor 901 can implement the following functions based on the data collected by the gyro sensor 912: motion sensing (such as changing the UI according to the user's tilt operation), image stabilization during shooting, game control, and inertial navigation.

[0143] The pressure sensor 913 can be set on the side frame of the electronic device 900 and / or the lower layer of the display screen 905. When the pressure sensor 913 is set on the side frame of the electronic device 900, it can detect the user's holding signal of the electronic device 900, and the processor 901 performs left and right hand recognition or shortcut operations according to the holding signal collected by the pressure sensor 913. When the pressure sensor 913 is set on the lower layer of the display screen 905, the processor 901 controls the operability controls on the UI interface according to the user's pressure operation on the display screen 905. The operability controls include at least one of a button control, a scroll bar control, an icon control, and a menu control.

[0144] The fingerprint sensor 914 is used to collect the user's fingerprint, and the processor 901 identifies the user's identity based on the fingerprint collected by the fingerprint sensor 914, or the fingerprint sensor 914 identifies the user's identity based on the collected fingerprint. When the user's identity is identified as a trusted identity, the processor 901 authorizes the user to perform relevant sensitive operations, which include unlocking the screen, viewing encrypted information, downloading software, paying, and changing settings. The fingerprint sensor 914 can be set on the front, back, or side of the electronic device 900. When a physical button or a manufacturer logo is set on the electronic device 900, the fingerprint sensor 914 can be integrated with the physical button or the manufacturer logo.

[0145] The optical sensor 915 is used to collect the ambient light intensity. In one embodiment, the processor 901 can control the display brightness of the display screen 905 according to the ambient light intensity collected by the optical sensor 915. Specifically, when the ambient light intensity is high, the display brightness of the display screen 905 is increased; when the ambient light intensity is low, the display brightness of the display screen 905 is reduced. In another embodiment, the processor 901 can also dynamically adjust the shooting parameters of the camera component 906 according to the ambient light intensity collected by the optical sensor 915.

[0146] The proximity sensor 916, also called a distance sensor, is usually disposed on the front panel of the electronic device 900. The proximity sensor 916 is used to collect the distance between the user and the front of the electronic device 900. In one embodiment, when the proximity sensor 916 detects that the distance between the user and the front of the electronic device 900 is gradually decreasing, the processor 901 controls the display screen 905 to switch from the screen-on state to the screen-off state; when the proximity sensor 916 detects that the distance between the user and the front of the electronic device 900 is gradually increasing, the processor 901 controls the display screen 905 to switch from the screen-off state to the screen-on state.

[0147] Those skilled in the art will understand that Fig. 9 The structure shown in the figure does not constitute a limitation on the electronic device 900, and may include more or less components than those shown in the figure, or combine some components, or adopt a different component arrangement.

[0148] In an exemplary embodiment, a computer-readable storage medium is also provided, such as a memory including instructions, which can be executed by a processor in a terminal to complete the method of controlling a back-to-back converter in the above embodiment. The computer-readable storage medium can be non-transitory. For example, the computer-readable storage medium can be a ROM (read-only memory), a RAM (random access memory), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, etc.

[0149] A person skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware or by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk or an optical disk, etc.

[0150] The above description is only an optional embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A method for controlling a back-to-back converter, characterized in that: The method comprises: During the operation of the back-to-back converter, obtaining an input voltage and an input current of a rectifier in the back-to-back converter; Determining a target reference voltage value of a DC bus in the back-to-back converter based on the input voltage and the input current; The switch tube in the rectifier is controlled based on the target reference voltage value.

2. The method according to claim 1, characterized in that The step of determining a target reference voltage value of a DC bus in the back-to-back converter based on the input voltage and the input current includes: Determining a voltage change of the DC bus based on a phase of the input voltage and a phase of the input current; Obtaining an initial setting value of the voltage of the DC bus; A target reference voltage value of the DC bus is determined based on an initial setting value of the voltage of the DC bus and the voltage variation.

3. The method according to claim 1 or 2, characterized in that: When the input current is greater than or equal to a first preset current threshold, the method further includes: Based on a relationship function between a reference voltage value for controlling a rectifier and a stress value of a switching device in the back-to-back converter, a target reference voltage value of the DC bus corresponding to the input current is determined.

4. The method according to claim 3, characterized in that The determining of the target reference voltage value of the DC bus corresponding to the input current based on the relationship function between the reference voltage value for controlling the rectifier and the stress value of the switch device in the back-to-back converter comprises: Based on the current stress value of the switch tube, the maximum reference voltage value of the DC bus is reduced to obtain the target reference voltage value, wherein the reduced value is positively correlated with the stress value.

5. The method according to claim 4, characterized in that The step of reducing the maximum reference voltage value of the DC bus based on the current stress value of the switch tube to obtain the target reference voltage value includes: Based on the formula V dcset =V dcmax -G c1 (V spike -V spikesafe ) determines the target reference voltage value, where V dcset is the target reference voltage value, V dcmax is the maximum reference voltage value, G c1 For the first voltage regulator controller, V spike is the current stress value of the switch tube, V spikesafe is the safety stress value of the switch tube.

6. The method according to claim 3, characterized in that The determining of the target reference voltage value of the DC bus corresponding to the input current based on the relationship function between the reference voltage value for controlling the rectifier and the stress value of the switch device in the back-to-back converter comprises: When the input current is less than or equal to the second current threshold, based on the current stress value of the switch tube, the maximum reference voltage value is reduced to obtain the target reference voltage value, wherein the reduced value is positively correlated with the stress value; When the input current is greater than the second current threshold, the target reference voltage value is determined to be a specified minimum reference voltage value.

7. The method according to claim 6, characterized in that The reducing the maximum reference voltage value based on the current stress value of the switch tube to obtain the target reference voltage value includes: Based on the formula V dcset =V dcmax -G c2 (V spike -V spikesafe ) determines the target reference voltage value, where V dcset is the target reference voltage value, V dcmax is the preset maximum reference voltage value, G c2 For the second voltage regulator controller, V spike is the current stress value of the switch tube, V spikesafe is the safety stress value of the switch tube.

8. A device for controlling a back-to-back converter, characterized in that: The device comprises: An acquisition module, used for acquiring an input voltage and an input current of a rectifier in the back-to-back converter during the operation of the back-to-back converter; A determination module, configured to determine a target reference voltage value of a DC bus in the back-to-back converter based on the input voltage and the input current; A control module is used to control the switch tube in the rectifier based on the target reference voltage value.

9. An electronic device, characterized in that: The electronic device includes a processor and a memory, wherein the memory stores at least one instruction, and the at least one instruction is loaded and executed by the processor to implement the operation performed by the method for controlling a back-to-back converter according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The storage medium stores at least one instruction, and the at least one instruction is loaded and executed by the processor to implement the operation performed by the method for controlling a back-to-back converter according to any one of claims 1 to 7.

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