Current feedforward control method and device and switching power supply

Abstract

The invention relates to a current feed-forward control method and device and a switching power supply. The control method comprises the following steps: acquiring a first voltage signal representing a DC bus voltage, a second voltage signal of an input voltage, a first current signal of an input current and a second current signal of a load current; calculating a current inner ring reference quantity by a voltage outer ring; calculating a current feed-forward quantity according to a power balance formula, and combining a fixed coefficient and efficiency in a current feed-forward quantity expression into a constant; superposing the current inner ring reference quantity IUdc and the current feed-forward quantity If to serve as a reference given value of a current inner ring, and adjusting a driving signal of the PFC circuit through the current inner ring; judging whether IUdc-If is smaller than a set threshold value or not when the PFC circuit is in a full-load state: if so, not adjusting a constant, and ending the control; and otherwise, if the IUdc is greater than If, increasing the constant and returning to the driving signal adjusting step, and if the IUdc is less than If, reducing the constant and returning to the driving signal adjusting step. According to the invention, the fluctuation amplitude and time of the DC bus voltage can be reduced when the load changes.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and in particular to a current feedforward control method, device and switching power supply. Background Art

[0002] With the rapid development of the power electronics industry, PFC circuits have been used more and more widely. The market's requirements for performance indicators such as power level and switching time are constantly increasing, which indirectly puts forward higher and higher requirements on the ability to respond to dynamic changes in DC loads. The traditional voltage outer loop and current inner loop double closed-loop control can no longer meet this requirement well. Therefore, some people have proposed to introduce a load current feedforward control strategy based on the traditional double closed-loop control. This control strategy is based on the principle of power balance and converts the energy required for the load switching process into a current feedforward quantity I f , and the current inner loop reference I output by the voltage outer loop PI controller Udc The given value of the current inner loop PI controller is obtained by superposition, so as to quickly make up for the input and output power shortage and achieve a fast and stable DC bus voltage U dc effect.

[0003] The inventor of the present application has found through research that the existing current feedforward quantity I f The calculation method is mostly a standard power balance calculation formula. However, this method has the problem of poor dynamic response of current feedforward control. This is because the efficiency η in this method varies with the input voltage and output load. The fluctuation of the sampling value and the calculation error of the microcontroller will also affect the effect of power compensation. In the steady-state operation of the actual circuit, if there is a large gap between the actual required output power and the theoretical calculated output power, the voltage inner loop will participate in the regulation of the current feedforward control process. At this time, if the load is switched dynamically, the voltage inner loop cannot be adjusted well, affecting the dynamic response characteristics of the DC bus voltage.

[0004] It should be noted that the information disclosed in the background technology section is only intended to deepen the understanding of the overall background technology of the present application, and should not be regarded as an admission or suggestion in any form that the information constitutes the prior art already known to those skilled in the art. In particular, the discovery of the above-mentioned prior art problems should not be regarded as an admission or suggestion in any form that the information constitutes the prior art already known to those skilled in the art. In the absence of clear evidence that the above-mentioned content has been disclosed on the filing date of this patent application, the above-mentioned background technology should not be used to evaluate the novelty and creativity of the present application. Summary of the invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a current feedforward control method, device and switching power supply to ensure that the current feedforward algorithm has better dynamic response characteristics in actual engineering.

[0006] As a first aspect of the present invention, the technical solution of the embodiment of the current feedforward control method provided is as follows:

[0007] A current feedforward control method is applied to a PFC circuit, wherein the current feedforward control method comprises the following steps:

[0008] The electrical parameter acquisition step is to acquire a first voltage signal U representing the DC bus voltage of the PFC circuit. dc , a second voltage signal U representing the input voltage of the PFC circuit in , a first current signal I representing the input current of the PFC circuit in and a second current signal I representing the load current of the PFC circuit R ;

[0009] The current inner loop reference quantity calculation step is to convert the first voltage signal U dc Compare with the set reference value to calculate the current inner loop reference value I udc ;

[0010] The current feedforward amount calculation step is based on the first voltage signal U dc , the second voltage signal U in , the second current signal I R 、Calculate the current feedforward value I based on the efficiency η of the PFC circuit f , calculated based on the power balance formula P in =P O ×η, where: P in is the input power of the PFC circuit, P O is the output power of the PFC circuit. In this step, the current feedforward value I f The fixed coefficient in the expression of and the efficiency η are combined into a constant K, and the initial value of the constant K is given according to the estimated value of η;

[0011] The driving signal adjustment step is to adjust the current inner loop reference quantity I udc and the current feedforward quantity I f After superposition, the reference given by the current inner loop is used to adjust the driving signal of the PFC circuit through the current inner loop, so that the DC bus voltage output by the PFC circuit reaches the expected value;

[0012] Constant K adjustment step, judging whether the PFC circuit satisfies |I under full load Udc -I f |<Set threshold: If yes, there is no need to adjust the constant K, and the control ends; otherwise, if I Udc >If Then increase the constant k and return to the drive signal adjustment step. If I Udc <I f Then the constant k is reduced and the process returns to the drive signal adjustment step.

[0013] Preferably, in the constant K adjustment step, the set threshold is 1.

[0014] Preferably, in the constant K adjustment step, if I Udc >I f , increase the constant K by 0.1 times.

[0015] Preferably, in the constant K adjustment step, if I Udc <I f , reduce the constant K by 0.1 times.

[0016] Furthermore, when the PFC circuit is a three-phase PFC circuit, the second voltage signal U in and the first current signal I in Obtained after DQ transformation.

[0017] Furthermore, when the PFC circuit is a three-phase PFC circuit, the current feed-forward amount I f The expression is as follows:

[0018]

[0019] Preferably, in the drive signal adjustment step, the DC bus voltage output by the PFC circuit reaches a desired value by adjusting the duty cycle and / or frequency of the drive signal.

[0020] Furthermore, in the current inner loop reference quantity calculation step, the current inner loop reference quantity I is calculated by a first PI controller. udc and / or in the drive signal adjustment step, the second PI controller controls the current inner loop reference quantity I udc and the current feedforward quantity I f Perform overlay processing.

[0021] As a second aspect of the present invention, the technical solution of the embodiment of the current feedforward control device provided is as follows:

[0022] A current feedforward control device is applied to a PFC circuit, wherein the current feedforward control device comprises the following units:

[0023] The electrical parameter acquisition unit is used to acquire a first voltage signal U representing the DC bus voltage of the PFC circuit. dc , a second voltage signal U representing the input voltage of the PFC circuitin , a first current signal I representing the input current of the PFC circuit in and a second current signal I representing the load current of the PFC circuit R ;

[0024] The current inner loop reference quantity calculation unit is used to convert the first voltage signal U dc Compare with the set reference value to calculate the current inner loop reference value I udc ;

[0025] A current feedforward calculation unit is used to calculate the current feedforward based on the first voltage signal U dc , the second voltage signal U in , the second current signal I R 、Calculate the current feedforward value I based on the efficiency η of the PFC circuit f , calculated based on the power balance formula P in =P O ×η, where: P in is the input power of the PFC circuit, P O is the output power of the PFC circuit. In this step, the current feedforward value I f The fixed coefficient in the expression of and the efficiency η are combined into a constant K, and the initial value of the constant K is given according to the estimated value of η;

[0026] The driving signal adjustment unit is used to adjust the current inner loop reference value I udc and the current feedforward quantity I f After superposition, the reference given by the current inner loop is used to adjust the driving signal of the PFC circuit through the current inner loop, so that the DC bus voltage output by the PFC circuit reaches the expected value;

[0027] The constant K adjustment unit is used to determine whether the PFC circuit meets the full load state |I Udc -I f |<Set threshold: If yes, there is no need to adjust the constant K, and the control ends; otherwise, if I Udc >I f Then increase the constant k and return to the drive signal adjustment step. If I Udc <I f Then the constant k is reduced and the process returns to the drive signal adjustment step.

[0028] As a third aspect of the present invention, the technical solution of the embodiment of the switching power supply provided is as follows:

[0029] A switching power supply, comprising a PFC circuit, wherein the PFC circuit is controlled by the current feedforward control device described in any one of the second aspects above.

[0030] Compared with the prior art, the embodiment of the present invention has the following effects: the current feedforward control algorithm is increased with an adjustable coefficient k, and compared with the solution without adjustment, the dynamic response process of the DC bus voltage of the PFC circuit is significantly improved. In addition, the actual current inner loop reference quantity I is adjusted when the PFC circuit is in a full load state. udc and the calculated current feedforward quantity I f The absolute value of the difference is used as a threshold value to determine the way to change k, so that k can be quickly adjusted to a suitable value. The embodiment of the present invention can optimize the effect of current feedforward control and further reduce the fluctuation amplitude and adjustment time of the PFC DC bus voltage during load disturbance. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flow chart of a current feedforward control method proposed in the first embodiment of the present invention;

[0032] Figure 2 A flow chart of a current feedforward control device proposed in a second embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of a specific circuit topology and control strategy of the switching power supply of the third embodiment of this embodiment;

[0034] Figure 4 for Figure 3 When the current feedforward control parameters of the switching power supply are not appropriate and the current feedforward does not participate in the operation, I Udc with I f Waveform;

[0035] Figure 5 for Figure 3 When the current feedforward control parameters of the switching power supply are not appropriate, the current feedforward is involved in the operation. Udc with I f Waveform;

[0036] Figure 6 for Figure 3 The bus voltage waveform when the current feedforward is involved in the operation when the current feedforward control parameters of the switching power supply are not appropriate;

[0037] Figure 7 for Figure 3 When the current feedforward control parameters of the switching power supply are appropriate, the current feedforward does not participate in the calculation. Udc with I f Waveform;

[0038] Figure 8 for Figure 3 When the current feedforward control parameters of the switching power supply are appropriate, the current feedforward is involved in the operation. Udc with I f Waveform;

[0039] Fig. 9 for Figure 3 The bus voltage waveform when the current feedforward is involved in the operation when the current feedforward control parameters of the switching power supply are appropriate. DETAILED DESCRIPTION

[0040] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0041] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0042] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application are described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, the process, method, system, product or equipment comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0043] It should be understood that, in the specification, claims and drawings, when a step is described as being connected to another step, the step may be directly connected to the other step, or be connected to the other step through a third step; when an element / unit is described as being "connected" to another element / unit, the element / unit may be "directly connected" to the other element / unit, or be "connected" to the other element / unit through a third element / unit.

[0044] The present invention designs a current feedforward control strategy and parameter setting method, improves the current feedforward link by using a mathematical equivalent model, and proposes a corresponding control parameter design method to ensure the best dynamic response of the busbar.

[0045] First embodiment

[0046] This embodiment provides a current feedforward control method, which is applied to a PFC circuit. Figure 2 This is a flow chart of a current feedforward control device proposed in a second embodiment of the present invention, wherein the current feedforward control method comprises the following steps:

[0047] The electrical parameter acquisition step S101 is to acquire a first voltage signal U representing the voltage of the DC bus of the PFC circuit. dc , a second voltage signal U representing the input voltage of the PFC circuit in , the first current signal I representing the input current of the PFC circuit in And a second current signal I representing the load current of the PFC circuit R ;

[0048] In the current inner loop reference quantity calculation step S102, the voltage outer loop converts the first voltage signal U dc Compare with the set reference value to calculate the current inner loop reference value I udc ;

[0049] The current feedforward amount calculation step S103 is based on the first voltage signal U dc , the second voltage signal U in , the second current signal I R 、Calculate the current feedforward value I based on the efficiency η of the PFC circuit f , calculated based on the power balance formula P in =P O ×η, where: P in is the input power of the PFC circuit, P O is the output power of the PFC circuit. In this step, the current feedforward value I f The fixed coefficient and efficiency η in the expression of are combined into a constant K, and the initial value of the constant K is given according to the estimated value of η;

[0050] In the drive signal adjustment step S104, the current inner loop adjusts the current inner loop reference value I udc and current feedforward I f After superposition, it is used as the reference given by the current inner loop, and the driving signal of the PFC circuit is adjusted through the current inner loop, so that the DC bus voltage output by the PFC circuit reaches the expected value;

[0051] Constant K adjustment step S105, judging whether the PFC circuit satisfies the full load state |I Udc -I f |<Set threshold: If yes, there is no need to adjust the constant K, and the control ends; otherwise, if I Udc >I f Then increase the constant k and return to the drive signal adjustment step. If I Udc <I f Then reduce the constant k and return to the drive signal adjustment step.

[0052] In the constant K adjustment step S105: when |I Udc -If |<When the threshold is set, this means that the calculated current feedforward amount I f The actual current inner loop reference I Udc The output power required by PFC is basically equal to the actual output power, which meets the requirement. There is no need to adjust the constant K, and the control ends. Udc -I f |>When setting the threshold, this means that the calculated current feedforward amount I f The actual current inner loop reference I Udc The error is large, and the gap between the output power required by PFC and the actual output power is large, which does not meet the requirements, so the constant K needs to be adjusted.

[0053] The control method of this embodiment increases the adjustable coefficient k of the current feedforward control algorithm. Compared with the scheme without adjustment, the dynamic response process of the DC bus voltage of the PFC circuit is significantly improved. In addition, the actual current inner loop reference quantity I is adjusted when the PFC circuit is in the full load state. udc and the calculated current feedforward quantity I f The absolute value of the difference is used as a threshold to determine the way to change k, so that k can be quickly adjusted to an appropriate value, thereby achieving the effect of optimizing current feedforward control and further reducing the fluctuation amplitude and adjustment time of the PFC DC bus voltage during load disturbances.

[0054] As a specific implementation, in the constant K adjustment step, the threshold is set to 1.

[0055] As a specific implementation, in the constant K adjustment step, if I Udc >I f , increase the constant K by 0.1 times, and then return to the current feedforward amount calculation step S103.

[0056] As a specific implementation, in the constant K adjustment step, if I Udc <I f , reduce the constant K by 0.1 times, and then calculate the current feedforward amount in step S103.

[0057] The PFC circuit used in the current feedforward control method of this embodiment can be either a single-phase PFC circuit or a three-phase PFC circuit. As a specific implementation method, when the PFC circuit is a three-phase PFC circuit, the second voltage signal U in and the first current signal I in Obtained after DQ transformation.

[0058] When the PFC circuit is a three-phase PFC circuit, the process of calculating the current feedforward amount by the power balance formula without considering the efficiency η is as follows:

[0059]

[0060] P out =U dc ×I R

[0061]

[0062] The current feedforward I after considering the efficiency η in the power balance formula f The expression is as follows:

[0063]

[0064] After replacing the efficiency η and the fixed coefficient 3 / 2 with the constant k, the current feedforward value I f The expression is as follows:

[0065]

[0066] As a specific implementation, in the drive signal adjustment step, the duty cycle and / or frequency of the drive signal is adjusted so that the DC bus voltage output by the PFC circuit reaches a desired value.

[0067] As a specific implementation, in the current inner loop reference quantity calculation step, the first PI controller calculates the current inner loop reference quantity I udc ; and / or in the drive signal adjustment step, the second PI controller is used to adjust the current inner loop reference quantity I udc and current feedforward I f Perform overlay processing.

[0068] Second embodiment

[0069] This embodiment provides a current feedforward control device, which is applied to a PFC circuit. Figure 2 This is a flow chart of a current feedforward control device proposed in the second embodiment of the present invention, wherein the current feedforward control device includes the following units:

[0070] The electrical parameter acquisition unit 100 is used to acquire a first voltage signal U representing the voltage of the DC bus. dc , a second voltage signal U representing the input voltage of the PFC circuit in , the first current signal I representing the input current of the PFC circuit in And a second current signal I representing the load current of the PFC circuit R ;

[0071] The current inner loop reference quantity calculation unit 200 is used to convert the first voltage signal U dc Compare with the set reference value to calculate the current inner loop reference value Iudc ;

[0072] The current feedforward calculation unit 300 is used to calculate the current feedforward value based on the first voltage signal U dc , the second voltage signal U in , the second current signal I R 、Calculate the current feedforward value I based on the efficiency η of the PFC circuit f , calculated based on the power balance formula P in =P O ×η, where: P in is the input power of the PFC circuit, P O is the output power of the PFC circuit. In this step, the current feedforward value I f The fixed coefficient and efficiency η in the expression of are combined into a constant K, and the initial value of the constant K is given according to the estimated value of η;

[0073] The driving signal adjustment unit 400 is used to adjust the current inner loop reference value I udc and current feedforward I f After superposition, it is used as the reference given by the current inner loop, and the driving signal of the PFC circuit is adjusted through the current inner loop, so that the DC bus voltage output by the PFC circuit reaches the expected value;

[0074] The constant K adjustment unit 500 is used to determine whether the PFC circuit meets the full load state |I Udc -I f |<Set threshold: If yes, there is no need to adjust the constant K, and the control ends; otherwise, if I Udc >I f Then increase the constant k and return to the drive signal adjustment step. If I Udc <I f Then reduce the constant k and return to the drive signal adjustment step.

[0075] The technical means adopted by the control device of this embodiment are consistent with the control method of the first embodiment, and the beneficial effects are the same, so they are not repeated; in addition, the preferred technical means or further improved means of each step in the control method of the first embodiment can be extended to the corresponding units of this embodiment, and this embodiment will not describe them one by one.

[0076] Third embodiment

[0077] This embodiment provides a switching power supply, which includes a PFC circuit, and the PFC circuit is controlled by any current feedforward control device in the second embodiment.

[0078] Since the PFC circuit of the switching power supply of this embodiment is controlled by any one of the current feedforward control devices in the second embodiment, it can ensure that the current feedforward algorithm has better dynamic response characteristics.

[0079] Figure 3 This is a specific circuit topology and control strategy diagram of the switching power supply of the third embodiment of this embodiment. The specific implementation steps of the current feedforward control are as follows:

[0080] S1: Collect the following Figure 3 The grid voltage U a , U b , U c , the power inductor current on the rectifier side or the input current on the grid side i a ,i b ,i c . Will U a , U b , U c and i a ,i b ,i c Perform dq transformation to get U in_d , U in_q and I in_d ,I in_q Since the present invention mainly improves the control of the active part, only the control strategy of the d-axis component is discussed, and the control strategy of the q-axis component is not discussed. in Indicates U in_d , use I in I in_q ;

[0081] S2: Based on DC bus voltage U dc Calculate the first PI output value I Udc , based on the DC bus voltage U dc 、Load current I R And AC side input voltage U in , through the conventional power balance formula P in = P0 calculates the current feedforward value I f , the specific implementation details are as follows:

[0082] Set the DC bus voltage rated value U dc * with U dc After the difference is taken, it is sent to the first PI and then output I Udc ;

[0083] The current feedforward is calculated according to the power balance formula. The calculation process has been detailed in the first embodiment. The current feedforward I f The expression is as follows:

[0084]

[0085] S4: Based on the first PI output value IUdc and the inductor current I in The second PI output value is calculated to control the duty cycle, thereby realizing DC bus voltage regulation control. The specific implementation details are as follows:

[0086] The first PI output value I Udc As the inductor current I in Reference value The current feedforward amount calculated at this time does not participate in the closed-loop control of the loop. The processing process after the second PI output belongs to the conventional control method and will not be repeated here;

[0087] S5: Determine the full load steady state |I Udc -I f |<Whether the threshold is set, if so, the control parameter k is determined and the step ends; otherwise, if I Udc >I f Then increase k, if I Udc <I f Then reduce k, and return to the previous step in either case.

[0088] In order to show the remarkable effect of the present invention, this embodiment is based on Figure 3 A specific switching power supply schematic diagram is given, and some experimental results are given. First, in the case of insufficient feedforward, under 220Vrms three-phase input full load steady state, such as Figure 4 and Figure 5 As shown ( Figure 4 The medium current is I Udc Waveform; Figure 5 The peak current is I Udc Waveform), current feedforward I f When only participating in loop calculation but not loop control f with I Udc The difference is nearly 8A, and then let the current feedforward amount I f After participating in the closed-loop control, the bus voltage dynamic response waveform is obtained, such as Figure 6 As shown; the second is the situation after the feedforward control parameter k is adjusted to a good state, under 220Vrms three-phase input full load steady state, as shown Figure 7 and Figure 8 As shown ( Figure 7 The current near 0s is I f Waveform; Figure 8 The peak current is I Udc Waveform), current feedforward I f Only participate in loop calculation I f with I Udc The phases are basically equal, and then the feedforward quantity is allowed to participate in the closed-loop control to obtain the bus voltage dynamic response waveform as follows Fig. 9 shown.

[0089] The above experimental results show that: when the k value is more appropriate, the bus output voltage fluctuation amplitude and adjustment time are much smaller than when the k value is inappropriate, resulting in insufficient current feedforward.

[0090] The above-mentioned embodiments of the present invention are merely examples for explaining the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes and modifications can be made based on the above description. It is impossible to list all the embodiments here. Any obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A current feedforward control method, applied to a PFC circuit, characterized in that: The current feedforward control method comprises the following steps: The electrical parameter acquisition step is to acquire a first voltage signal U representing the DC bus voltage of the PFC circuit. dc , a second voltage signal U representing the input voltage of the PFC circuit in , a first current signal I representing the input current of the PFC circuit in and a second current signal I representing the load current of the PFC circuit R ; The current inner loop reference quantity calculation step is to convert the first voltage signal U dc Compare with the set reference value to calculate the current inner loop reference value I udc ; The current feedforward amount calculation step is based on the first voltage signal U dc , the second voltage signal U in , the second current signal I R 、Calculate the current feedforward value I based on the efficiency η of the PFC circuit f , calculated based on the power balance formula P in =P O ×η, where: P in is the input power of the PFC circuit, P O is the output power of the PFC circuit. In this step, the current feedforward value I f The fixed coefficient in the expression of and the efficiency η are combined into a constant K, and the initial value of the constant K is given according to the estimated value of η; The driving signal adjustment step is to adjust the current inner loop reference quantity I udc and the current feedforward quantity I f After superposition, the reference given by the current inner loop is used to adjust the driving signal of the PFC circuit through the current inner loop, so that the DC bus voltage output by the PFC circuit reaches the expected value; Constant K adjustment step, judging whether the PFC circuit satisfies |I under full load Udc -I f |<Set threshold: If yes, there is no need to adjust the constant K, and the control ends; otherwise, if I Udc >I f Then increase the constant k and return to the drive signal adjustment step. If I Udc <I f Then the constant k is reduced and the process returns to the drive signal adjustment step.

2. The flow feedforward control method according to claim 1, characterized in that: In the constant K adjustment step, the set threshold is 1.

3. The flow feedforward control method according to claim 1, characterized in that: In the constant K adjustment step, if I Udc >I f , increase the constant K by 0.1 times.

4. The flow feedforward control method according to claim 1, characterized in that: In the constant K adjustment step, if I Udc <I f , reduce the constant K by 0.1 times.

5. The flow feedforward control method according to claim 1, characterized in that: When the PFC circuit is a three-phase PFC circuit, the second voltage signal U in and the first current signal I in Obtained after DQ transformation.

6. The flow feedforward control method according to claim 1, characterized in that: When the PFC circuit is a three-phase PFC circuit, the current feedforward amount I f The expression is as follows:

7. The flow feedforward control method according to claim 1, characterized in that: In the drive signal adjustment step, the DC bus voltage output by the PFC circuit reaches a desired value by adjusting the duty cycle and / or frequency of the drive signal.

8. The flow feedforward control method according to claim 1, characterized in that: In the current inner loop reference quantity calculation step, the current inner loop reference quantity I is calculated by a first PI controller. udc and / or in the drive signal adjustment step, the second PI controller controls the current inner loop reference quantity I udc and the current feedforward quantity I f Perform overlay processing.

9. A current feedforward control device, applied to a PFC circuit, characterized in that: The current feedforward control device comprises the following units: The electrical parameter acquisition unit is used to acquire a first voltage signal U representing the DC bus voltage of the PFC circuit. dc , a second voltage signal U representing the input voltage of the PFC circuit in , a first current signal I representing the input current of the PFC circuit in and a second current signal I representing the load current of the PFC circuit R ; The current inner loop reference quantity calculation unit is used to convert the first voltage signal U dc Compare with the set reference value to calculate the current inner loop reference value I udc ; A current feedforward calculation unit is used to calculate the current feedforward based on the first voltage signal U dc , the second voltage signal U in , the second current signal I R 、Calculate the current feedforward value I based on the efficiency η of the PFC circuit f , calculated based on the power balance formula P in =P O ×η, where: P in is the input power of the PFC circuit, P O is the output power of the PFC circuit. In this step, the current feedforward value I f The fixed coefficient in the expression of and the efficiency η are combined into a constant K, and the initial value of the constant K is given according to the estimated value of η; The driving signal adjustment unit is used to adjust the current inner loop reference value I udc and the current feedforward quantity I f After superposition, the reference given by the current inner loop is used to adjust the driving signal of the PFC circuit through the current inner loop, so that the DC bus voltage output by the PFC circuit reaches the expected value; The constant K adjustment unit is used to determine whether the PFC circuit meets the full load state |I Udc -I f |<Set threshold: If yes, there is no need to adjust the constant K, and the control ends; otherwise, if I Udc >I f Then increase the constant k and return to the drive signal adjustment step. If I Udc <I f Then the constant k is reduced and the process returns to the drive signal adjustment step.

10. A switching power supply, characterized in that: The invention comprises a PFC circuit, wherein the PFC circuit is controlled by the current feedforward control device according to claim 9.

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