Control method, device and equipment of three-phase single-tube PFC (Power Factor Correction) circuit and medium

Abstract

The invention discloses a control method and device of a three-phase single-tube PFC circuit, equipment and a medium. The invention relates to the technical field of PFC circuits, and the method comprises the steps: collecting a sampling current and an output voltage of a three-phase single-tube PFC circuit under a current beat, and calculating a reference current according to the output voltage; performing linear extrapolation on the sampling current to obtain an inductive current, and calculating a duty ratio of a switching tube in a switching period in the next beat according to the inductive current, the reference current and the output voltage; and controlling a switching tube in the three-phase single-tube PFC circuit according to the duty ratio of the switching tube. According to the invention, the input current can be improved, the THD of the input current can be reduced, the input voltage can be tracked without a static error, and the problem that the input voltage has a static error is solved.

Description

Technical Field

[0001] Embodiments of the present invention relate to the technical field of PFC circuits, and in particular to a control method, apparatus, device, and medium for a three-phase single-tube PFC circuit. Background Art

[0002] Existing three-phase PFC (Power Factor Correction) circuits can be divided into three-phase passive PFC circuits and three-phase active PFC circuits. Due to the limitations of its own topology, the power factor of three-phase passive PFC circuits is difficult to improve. In addition, its inductor and capacitor are relatively large in size and weight, which will have a significant impact on the operating performance of the load. Three-phase active PFC circuits mainly use power electronic devices such as switching tubes to process the input current, so that the current follows the input phase voltage, thereby improving the power factor at the input end. It can also regulate and control the output voltage to keep it relatively stable. The topology of three-phase active PFC circuits can be mainly divided into three-phase six-transistor PFC circuits, three-phase three-transistor PFC circuits, three-phase two-transistor PFC circuits and three-phase single-transistor PFC circuits according to the number of switching tubes used. Although the three-phase single-transistor PFC circuit has a simple circuit, low cost and relatively good performance, it must operate in DCM (Discontinuous Conduction Mode) to complete PFC. In addition, the traditional proportional-integral regulator will have a static error problem with the AC input voltage. Summary of the Invention

[0003] Embodiments of the present invention provide a control method, apparatus, device, and medium for a three-phase single-switch PFC circuit, aiming to solve the problem of static errors in input current and input voltage that need to be improved in existing three-phase single-switch PFC circuits.

[0004] In a first aspect, an embodiment of the present invention provides a control method for a three-phase single-switch PFC circuit, including:

[0005] Collect the sampled current and output voltage of the three-phase single-tube PFC circuit at the current beat, and calculate the reference current based on the output voltage;

[0006] Performing linear extrapolation on the sampled current to obtain an inductor current, and calculating a switch duty cycle of a switching cycle in a next beat according to the inductor current, the reference current, and the output voltage;

[0007] The switch tube in the three-phase single-tube PFC circuit is controlled according to the switch tube duty cycle.

[0008] In a second aspect, an embodiment of the present invention further provides a control device for a three-phase single-switch PFC circuit, comprising:

[0009] An acquisition and calculation unit is used to acquire the sampled current and output voltage of the three-phase single-tube PFC circuit at the current beat, and calculate the reference current according to the output voltage;

[0010] an extrapolation calculation unit, configured to perform linear extrapolation on the sampled current to obtain an inductor current, and calculate a duty cycle of the switch tube in a switching cycle in a next beat according to the inductor current, the reference current, and the output voltage;

[0011] A control unit is used to control the switch tube in the three-phase single-tube PFC circuit according to the duty cycle of the switch tube.

[0012] In a third aspect, an embodiment of the present invention further provides an electronic device, comprising a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the above method when executing the computer program.

[0013] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium, wherein the storage medium stores a computer program, and the computer program can implement the above method when executed by a processor.

[0014] An embodiment of the present invention provides a control method, device, equipment, and medium for a three-phase single-tube PFC circuit. The method includes: collecting the sampled current and output voltage of the three-phase single-tube PFC circuit in the current beat, and calculating a reference current based on the output voltage; linearly extrapolating the sampled current to obtain the inductor current, and calculating the switch duty cycle of the switching tube in the next beat based on the inductor current, the reference current, and the output voltage; and controlling the switch tube in the three-phase single-tube PFC circuit based on the switch duty cycle. The technical solution of the embodiment of the present invention, which linearly extrapolates the sampled current to obtain the inductor current and controls the switch tube in the three-phase single-tube PFC circuit based on the switch duty cycle, can not only improve the input current and reduce the THD (Total Harmonic Distortion) of the input current, but also enable the input voltage to track without static error, thereby solving the problem of static error in the input voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1A schematic flow chart of a control method for a three-phase single-switch PFC circuit provided by an embodiment of the present invention;

[0017] Figure 2 A schematic diagram of a three-phase single-tube PFC circuit provided by an embodiment of the present invention;

[0018] Figure 3 A schematic diagram of a sub-flow chart of a control method for a three-phase single-switch PFC circuit provided by an embodiment of the present invention;

[0019] Figure 4 A schematic diagram of another sub-flow chart of a control method for a three-phase single-switch PFC circuit provided by an embodiment of the present invention;

[0020] Figure 5 A simplified flow chart of a control method for a three-phase single-switch PFC circuit provided by an embodiment of the present invention;

[0021] Figure 6 A schematic block diagram of a control device for a three-phase single-switch PFC circuit provided by an embodiment of the present invention;

[0022] Figure 7 A schematic block diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0024] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0025] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the present invention. As used in the specification and appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0026] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0027] As used in this specification and the appended claims, the term "if" can be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0028] See also Figure 1 , Figure 1 1 is a flow chart of a control method for a three-phase single-tube PFC circuit provided by an embodiment of the present invention. The control method for the three-phase single-tube PFC circuit is described in detail below. Figure 1 As shown, the method includes the following steps S110-S130.

[0029] S110 , collecting a sampled current and an output voltage of a three-phase single-tube PFC circuit at a current beat, and calculating a reference current according to the output voltage.

[0030] In the embodiment of the present invention, for ease of understanding, the three-phase single-tube PFC circuit is first explained. The three-phase single-tube PFC circuit in this embodiment is a three-phase single-tube Boost type PFC circuit. Figure 2As shown, the three-phase single-tube Boost PFC circuit includes a rectifier circuit and a control circuit. The rectifier circuit includes three-phase AC input terminals, which are Ua, Ub, and Uc respectively. The rectifier circuit also includes an inductor La, an inductor Lb, an inductor Lc, a switch tube S1, a capacitor C, a capacitor C1, a capacitor C2, a capacitor C3, a diode D, a diode D, a diode D1, a diode D2, a diode D3, a diode D4, a diode D5, a diode D6, and a resistor R. The inductor La, the inductor Lb, and the inductor Lc are energy storage inductors and are equal. The three-phase AC input terminals of the three-phase single-tube Boost PFC circuit are connected in a Y-type manner using three capacitors (capacitor C1, capacitor C2, capacitor C3). The three-phase capacitors (capacitor C1, capacitor C2, capacitor C3) are used for reactive power compensation and form a second-order filter with the inductor La, the inductor Lb, and the inductor Lc. Switch S1 is a single-tube controlled switch that operates in PWM mode. It is in a zero-current on-state and does not withstand the reverse recovery current of the diode, resulting in low switching losses. PWM (Pulse Width Modulation) is a modulation technique that controls voltage, current, or power by adjusting the duty cycle of a pulse signal (the proportion of the high-level time to the entire cycle). Capacitor C is a DC filter capacitor that keeps the output voltage essentially unchanged during the power frequency cycle. The power frequency cycle refers to the on-off cycle of switch S1, i.e., the switching cycle of switch S1. The operating mode of this three-phase single-tube Boost PFC circuit is discontinuous conduction mode. The input current peak is proportional to the input voltage, and the input current waveform follows the input voltage waveform. It should be noted that in this embodiment, the control circuit includes PWM modulation, deadbeat control, linear extrapolation, and a PI regulator. The PI regulator (proportional-integral regulator) is a closed-loop controller widely used in power electronic control systems. It dynamically adjusts the output signal to eliminate the error between the system's actual value and the target value. PWM (Pulse Width Modulation) is a modulation technique that controls voltage, current, or power by adjusting the duty cycle of a pulse signal (the proportion of the high-level time to the entire cycle). Deadbeat control is digital deadbeat current mode control. This current estimation is performed through linear extrapolation. Current samples from two adjacent cycles are linearly extrapolated to estimate the inductor current one cycle in advance, before the next sampling point arrives. Because the inductor current is estimated one cycle in advance, the duration of one cycle is available for calculation. The controller adjusts the duty cycle of the next cycle based on the estimated inductor current from the current cycle, thereby adjusting the current to a reference value. This method is simple, reliable, robust, and easy to implement. It should also be noted that, in this embodiment, the control circuit adopts dual-loop control, the outer loop control is voltage loop control, and the inner loop control is current loop control. The voltage loop control adopts PI control, and the current loop control adopts deadbeat control.

[0031] In this embodiment of the present invention, a controller of a three-phase single-switch PFC circuit determines whether the PFC control logic needs to be enabled. If so, the controller enables the PFC control logic, collects the sampled current Ifdb and output voltage U0 of the three-phase single-switch PFC circuit at the current cycle, and calculates a reference current Iref based on the output voltage U0. Specifically, the controller obtains the reference voltage Uref, calculates the difference between the reference voltage Uref and the output voltage U0, and obtains a voltage difference Δv = (Uref - U0). This voltage difference Δv is then input into a PI regulator to obtain the reference current Iref.

[0032] S120 , performing linear extrapolation on the sampled current to obtain an inductor current, and calculating a switch duty cycle of a switching cycle in a next beat according to the inductor current, the reference current, and the output voltage.

[0033] In an embodiment of the present invention, the sampled current includes a first sampled current and a second sampled current. Each beat includes two switching cycles, and the two switching cycles have the same duty cycle. The controller performs current sampling at the starting point of each switching cycle to obtain the first sampled current and the second sampled current. The sampled currents of two adjacent switching cycles (the first sampled current and the second sampled current) are then linearly extrapolated to obtain the inductor current of the next cycle.

[0034] In one embodiment, such as this embodiment, Figure 3 As shown, step S120 may specifically include steps S121-S125:

[0035] S121, calculating the product of the second sampling current and a preset multiple to obtain a target sampling current;

[0036] S122. Calculate the difference between the target sampling current and the first sampling current to obtain the inductor current;

[0037] S123, calculating the product of the voltage difference and the switching period to obtain an initial target voltage difference;

[0038] S124, calculating the difference between the reference current and the inductor current to obtain an initial current difference;

[0039] S125 , calculating the switch duty cycle of the switching cycle in the next beat according to the initial target voltage difference, the output voltage, the initial current difference, the output current, and the switching cycle.

[0040] In an embodiment of the present invention, the preset multiple is 2. Assuming that in the kth cycle, the first sampled current of the first switching cycle is I(k,1), and the second sampled current of the second switching cycle is I(k,2), where k ≥ 1; since the duty cycles of the two cycles within each cycle are the same, the input and output voltages can also be considered constant, so the change in current is also equal. Based on this, linear interpolation can be performed to obtain the inductor current Iest one cycle in advance. The target sampled current is 2I(k,2). As shown in formula (1), after obtaining the inductor current Iest(k) of the kth cycle, the controller replaces I(k+1,1) with Iest(k), that is, replaces the first sampled current of the first switching cycle of the k+1th cycle with the inductor current of the kth cycle, thereby obtaining current information one cycle in advance. After current estimation, the controller calculates the duty cycle of the switch tube in the switching cycle of the next cycle based on Iest(k), the reference current Iref, and the output voltage U0.

[0041] I est (k)=2I(k,2)-I(k,1) (1)

[0042] Specifically, the step of calculating the duty cycle of the switching tube in the switching cycle in the next beat based on the initial target voltage difference, the output voltage, the initial current difference, the output current and the switching cycle includes: calculating the product of the initial target voltage difference and a preset multiple to obtain a target voltage difference; calculating the product of the initial current difference and the inductance in the three-phase single-tube PFC circuit to obtain a target current difference; calculating the product of the target voltage difference and the target current difference to obtain a voltage-current sum; calculating the product of the preset multiple, the output voltage and the switching cycle to obtain a voltage product; and calculating the quotient of the voltage-current sum and the voltage product to obtain the duty cycle of the switching tube in the switching cycle in the next beat.

[0043] More specifically, as shown in formula (2), the difference between the reference voltage Uref and the output voltage U0 is calculated to obtain a voltage difference Δv = (Uref - U0). The product of (Uref - U0) and the switching period T is calculated to obtain an initial target voltage difference. The product of the initial target voltage difference and a preset multiple of 2 is calculated to obtain a target voltage difference 2T(Uref - Uo). Assuming that the reference current of the k-th beat is Iref(k), the difference between Iref(k) and the inductor current Iest(k) of the k-th beat is calculated to obtain an initial current difference (Iref(k) - Iest(k)). The inductor L in the three-phase single-tube PFC circuit is multiplied by (Iref(k) - Iest(k)) to obtain the target current difference. The voltage and current sum is 2T(Uref - Uo) + L(Iref(k) - Iest(k)), and the voltage product is 2TUo. D(k+1) in formula (2) is the duty cycle of the switch tube in the k+1-th switching period.

[0044]

[0045] It should be noted that, in this embodiment, the output voltage Uo is compared with the reference voltage Uref, and the duty cycle of the switch tube is continuously adjusted so that the switch control amount accurately follows the control reference value within one switching cycle to achieve output voltage stability.

[0046] S130 : Control the switch tube in the three-phase single-tube PFC circuit according to the switch tube duty cycle.

[0047] In the embodiment of the present invention, the switch tube duty cycle is the PWM signal duty cycle, and the switch tube in the three-phase single-tube PFC circuit is turned on and off according to the switch tube duty cycle.

[0048] In one embodiment, such as this embodiment, Figure 4 As shown, step S130 may specifically include steps S131-S136:

[0049] S131, determining whether the duty cycle of the switch tube is greater than a preset maximum duty cycle of the switch tube; if the duty cycle of the switch tube is greater than the preset maximum duty cycle of the switch tube, executing step S132; otherwise, executing step S134;

[0050] S132: Setting the switch duty cycle to the preset maximum switch duty cycle to obtain a target switch duty cycle;

[0051] S133, controlling the switch tube in the three-phase single-tube PFC circuit according to the target duty cycle of the switch tube;

[0052] S134, determining whether the duty cycle of the switch tube is less than a preset minimum value of the switch tube duty cycle; if the duty cycle of the switch tube is less than the preset minimum value of the switch tube duty cycle, executing step S135; otherwise, executing step S136;

[0053] S135, setting the switch duty cycle to the preset minimum switch duty cycle to obtain the switch target duty cycle, and executing step S133;

[0054] S136 . Control the switch tube in the three-phase single-tube PFC circuit according to the switch tube duty cycle.

[0055] In this embodiment of the present invention, for ease of description, it is assumed that the switch duty cycle is D, the maximum value of the switch duty cycle is preset to 0.95, and the minimum value of the switch duty cycle is preset to 0.05. A determination is made as to whether D is greater than 0.95. If so, D is set to 0.95, and the switch in the three-phase single-transistor PFC circuit is turned on and off based on 0.95. If not, a determination is then made as to whether D is less than 0.05. If so, D is set to 0.05, and the switch in the three-phase single-transistor PFC circuit is turned on and off based on 0.05. If not, the switch in the three-phase single-transistor PFC circuit is turned on and off based on the switch duty cycle. It is understood that the next sampling time of the controller can be determined based on the switch duty cycle. By continuously updating and calculating the switch duty cycle, the output voltage U0 can be made to track the reference voltage Uref.

[0056] See also Figure 5 , Figure 5 A simplified flow chart of a control method for a three-phase single-tube PFC circuit provided by an embodiment of the present invention is shown in FIG. Figure 5 The entire process of the controller of the three-phase single-tube PFC circuit controlling the three-phase single-tube PFC circuit is briefly described. The specific control steps are as described above and will not be repeated here for the sake of simplicity.

[0057] In summary, the control method for the three-phase single-switch PFC circuit in this embodiment uses dual-loop control (the outer loop is voltage loop control, and the inner loop is current loop control, with the voltage loop adopting PI control and the current loop adopting deadbeat control) to linearly extrapolate the sampled current to obtain the inductor current. The switch in the three-phase single-switch PFC circuit is then controlled according to its duty cycle. This method not only improves the input current and reduces the THD of the input current, but also enables the input voltage to track without static error, resulting in a higher power factor and lower harmonic content, thus solving the problem of static error in the input voltage. Furthermore, the method is simple, reliable, robust, and easy to implement.

[0058] Figure 6 FIG is a schematic block diagram of a control device 200 for a three-phase single-tube PFC circuit provided by an embodiment of the present invention. Figure 6 As shown, corresponding to the above control method of the three-phase single-tube PFC circuit, the present invention also provides a control device 200 for the three-phase single-tube PFC circuit. The control device 200 for the three-phase single-tube PFC circuit includes a unit for executing the above control method of the three-phase single-tube PFC circuit, and the device can be configured in an electronic device. Specifically, please refer to Figure 6 The control device 200 of the three-phase single-tube PFC circuit includes an acquisition calculation unit 201, an extrapolation calculation unit 202 and a control unit 203.

[0059] Among them, the acquisition and calculation unit 201 is used to collect the sampled current and output voltage of the three-phase single-tube PFC circuit in the current beat, and calculate the reference current based on the output voltage; the extrapolation calculation unit 202 is used to linearly extrapolate the sampled current to obtain the inductor current, and calculate the switch tube duty cycle in the switching cycle in the next beat based on the inductor current, the reference current and the output voltage; the control unit 203 is used to control the switch tube in the three-phase single-tube PFC circuit according to the switch tube duty cycle.

[0060] In some embodiments, such as this embodiment, the acquisition and calculation unit 201 is specifically used to: obtain a reference voltage, and calculate the difference between the reference voltage and the output voltage to obtain a voltage difference; and input the voltage difference into a PI regulator to obtain the reference current.

[0061] In certain embodiments, such as the present embodiment, the extrapolation calculation unit 202 is specifically configured to: calculate the product of the second sampling current and a preset multiple to obtain a target sampling current; calculate the difference between the target sampling current and the first sampling current to obtain the inductor current; calculate the product of the voltage difference and the switching period to obtain an initial target voltage difference; calculate the difference between the reference current and the inductor current to obtain an initial current difference; and calculate the duty cycle of the switch tube in the switching period in the next beat based on the initial target voltage difference, the output voltage, the initial current difference, the output current, and the switching period.

[0062] In certain embodiments, such as the present embodiment, the extrapolation calculation unit 202 is further configured to: calculate the product of the initial target voltage difference and a preset multiple to obtain a target voltage difference; calculate the product of the initial current difference and the inductance in the three-phase single-tube PFC circuit to obtain a target current difference; calculate the product of the target voltage difference and the target current difference to obtain a voltage-current sum; calculate the product of the preset multiple, the output voltage, and the switching period to obtain a voltage product; and calculate the quotient of the voltage-current sum and the voltage product to obtain a duty cycle of the switching tube in the switching period in the next beat.

[0063] In some embodiments, such as the present embodiment, the control unit 203 is further configured to: determine whether the duty cycle of the switch tube is greater than a preset maximum duty cycle of the switch tube; if the duty cycle of the switch tube is greater than the preset maximum duty cycle of the switch tube, set the duty cycle of the switch tube to the preset maximum duty cycle of the switch tube to obtain a target duty cycle of the switch tube; control the switch tube in the three-phase single-tube PFC circuit according to the target duty cycle of the switch tube; if the duty cycle of the switch tube is not greater than the preset maximum duty cycle of the switch tube, determine whether the duty cycle of the switch tube is greater than the preset maximum duty cycle of the switch tube; whether the duty cycle of the switching tube is less than a preset minimum value of the switching tube duty cycle; if the switching tube duty cycle is less than the preset minimum value of the switching tube duty cycle, setting the switching tube duty cycle to the preset minimum value of the switching tube duty cycle to obtain the switching tube target duty cycle, and executing the step of controlling the switching tube in the three-phase single-tube PFC circuit according to the switching tube target duty cycle; if the switching tube duty cycle is not less than the preset minimum value of the switching tube duty cycle, controlling the switching tube in the three-phase single-tube PFC circuit according to the switching tube duty cycle.

[0064] The control device of the three-phase single-tube PFC circuit can be implemented in the form of a computer program. The computer program can be used in Figure 7 Runs on the electronic devices shown.

[0065] See also Figure 7 , Figure 7 1 is a schematic block diagram of an electronic device provided by an embodiment of the present invention. The electronic device 300 is a device having a control function of a three-phase single-tube PFC circuit.

[0066] See Figure 7 The electronic device 300 includes a processor 302 , a memory, and a network interface 305 connected via a system bus 301 , wherein the memory may include a non-volatile storage medium 303 and an internal memory 304 .

[0067] The non-volatile storage medium 303 may store an operating system 3031 and a computer program 3032. When the computer program 3032 is executed, the processor 302 may execute a control method for a three-phase single-transistor PFC circuit.

[0068] The processor 302 is used to provide computing and control capabilities to support the operation of the entire electronic device 300.

[0069] The internal memory 304 provides an environment for the operation of the computer program 3032 in the non-volatile storage medium 303. When the computer program 3032 is executed by the processor 302, the processor 302 can execute a control method for a three-phase single-transistor PFC circuit.

[0070] The network interface 305 is used to communicate with other devices through the network. Figure 7 The structure shown in the figure is merely a block diagram of a portion of the structure related to the solution of the present invention, and does not constitute a limitation on the electronic device 300 to which the solution of the present invention is applied. The specific electronic device 300 may include more or fewer components than those shown in the figure, or combine certain components, or have a different component arrangement.

[0071] The processor 302 is configured to run a computer program 3032 stored in a memory to implement any embodiment of the above-mentioned control method for a three-phase single-switch PFC circuit.

[0072] It should be understood that in the embodiment of the present invention, the processor 302 may be a central processing unit (CPU), and the processor 302 may also be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0073] Those skilled in the art will appreciate that all or part of the steps in the method of the above-described embodiment can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. The computer program is executed by at least one processor in the computer system to implement the steps in the method of the above-described embodiment.

[0074] Therefore, the present invention further provides a storage medium. The storage medium may be a computer-readable storage medium. The storage medium stores a computer program. When executed by a processor, the computer program causes the processor to execute any embodiment of the control method for a three-phase single-switch PFC circuit.

[0075] The storage medium may be any computer-readable storage medium that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a magnetic disk, or an optical disk.

[0076] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the composition and steps of each example according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0077] In the several embodiments provided herein, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the various units is merely a logical functional division, and actual implementation may employ other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be omitted or not implemented.

[0078] The steps in the methods of the embodiments of the present invention may be adjusted in order, combined, or deleted as needed. The units in the devices of the embodiments of the present invention may be combined, divided, or deleted as needed. Furthermore, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit.

[0079] If this integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes a number of instructions for causing an electronic device to perform all or part of the steps of the method described in various embodiments of the present invention.

[0080] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0081] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, to the extent such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to encompass such changes and modifications.

[0082] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and such modifications or substitutions are intended to be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A control method for a three-phase single-tube PFC circuit, characterized in that: include: Collect the sampled current and output voltage of the three-phase single-tube PFC circuit at the current beat, and calculate the reference current based on the output voltage; Performing linear extrapolation on the sampled current to obtain an inductor current, and calculating a switch duty cycle of a switching cycle in a next beat according to the inductor current, the reference current, and the output voltage; The switch tube in the three-phase single-tube PFC circuit is controlled according to the switch tube duty cycle.

2. The method according to claim 1, characterized in that The step of calculating the reference current according to the output voltage comprises: Obtaining a reference voltage, and calculating a difference between the reference voltage and the output voltage to obtain a voltage difference; The voltage difference is input into a PI regulator to obtain the reference current.

3. The method according to claim 2, characterized in that The step of calculating the duty cycle of the switch tube in the switching cycle in the next beat according to the inductor current, the reference current and the output voltage includes: Calculating the product of the voltage difference and the switching period to obtain an initial target voltage difference; Calculating a difference between the reference current and the inductor current to obtain an initial current difference; The switch duty cycle of the switching cycle in the next beat is calculated according to the initial target voltage difference, the output voltage, the initial current difference, the output current, and the switching cycle.

4. The method according to claim 3, characterized in that The step of calculating the switch duty cycle of the switching cycle in the next beat according to the initial target voltage difference, the output voltage, the initial current difference, the output current, and the switching cycle includes: Calculating the product of the initial target voltage difference and a preset multiple to obtain a target voltage difference; Calculating the product of the initial current difference and the inductance in the three-phase single-tube PFC circuit to obtain a target current difference; Calculating the product of the target voltage difference and the target current difference to obtain a voltage and current sum; Calculating the product of the preset multiple, the output voltage, and the switching period to obtain a voltage product; The quotient of the voltage-current sum and the voltage product is calculated to obtain the duty cycle of the switch tube in the switching cycle in the next beat.

5. The method according to claim 1, wherein The sampling current includes a first sampling current and a second sampling current, and the step of linearly extrapolating the sampling current to obtain the inductor current includes: Calculating the product of the second sampling current and a preset multiple to obtain a target sampling current; The inductor current is obtained by calculating a difference between the target sampling current and the first sampling current.

6. The method according to any one of claims 1 to 5, characterized in that The step of controlling the switch tube in the three-phase single-tube PFC circuit according to the switch tube duty cycle includes: Determining whether the duty cycle of the switch tube is greater than a preset maximum duty cycle of the switch tube; If the switch duty cycle is greater than the preset maximum switch duty cycle, setting the switch duty cycle to the preset maximum switch duty cycle to obtain a target switch duty cycle; The switching tube in the three-phase single-tube PFC circuit is controlled according to the target duty cycle of the switching tube.

7. The method according to claim 6, characterized in that After the step of determining whether the duty cycle of the switch tube is greater than the preset maximum duty cycle of the switch tube, the method further includes: If the switch duty cycle is not greater than the preset maximum switch duty cycle, determining whether the switch duty cycle is less than the preset minimum switch duty cycle; If the switch duty cycle is less than the preset minimum switch duty cycle value, setting the switch duty cycle to the preset minimum switch duty cycle value to obtain the switch target duty cycle, and performing the step of controlling the switch in the three-phase single-tube PFC circuit according to the switch target duty cycle; If the duty cycle of the switch tube is not less than the preset minimum duty cycle of the switch tube, the switch tube in the three-phase single-tube PFC circuit is controlled according to the duty cycle of the switch tube.

8. A control device for a three-phase single-tube PFC circuit, characterized in that: include: An acquisition and calculation unit is used to acquire the sampled current and output voltage of the three-phase single-tube PFC circuit at the current beat, and calculate the reference current according to the output voltage; an extrapolation calculation unit, configured to perform linear extrapolation on the sampled current to obtain an inductor current, and calculate a duty cycle of the switch tube in a switching cycle in a next beat according to the inductor current, the reference current, and the output voltage; A control unit is used to control the switch tube in the three-phase single-tube PFC circuit according to the duty cycle of the switch tube.

9. An electronic device, characterized in that: The electronic device includes a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the method according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium, characterized in that The storage medium stores a computer program, and when the computer program is executed by a processor, the computer program can implement the method according to any one of claims 1 to 7.

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