PFC circuit control method and device, PFC circuit and air conditioner

Abstract

The application provides a PFC circuit control method and device, a PFC circuit and an air conditioner. The method comprises the following steps: periodically obtaining a bus voltage average value during air conditioner operation; calculating a difference value of adjacent bus voltage average values; determining a compensated duty cycle according to an initial duty cycle, the difference value and a preset compensation coefficient; the compensated duty cycle is positively correlated with the difference value; adjusting a PWM signal according to the compensated duty cycle; and controlling the on-off of a power device according to the adjusted PWM signal. The application can compensate the duty cycle of the PWM signal based on the bus voltage reduction value, quickly adjust the bus voltage to recover to a stable state by increasing the duty cycle of the PWM signal, thereby improving the stability of the system, reducing the probability of over-current protection caused by bus voltage drop to a certain extent, reducing the fault shutdown condition and improving the user experience.

Description

Technical Field

[0001] This invention relates to the field of PFC technology, and more specifically, to a PFC circuit control method, device, PFC circuit, and air conditioner. Background Technology

[0002] The Boost-type Power Factor Correction (PFC) circuit using the average current method in air conditioners can adjust the given reference voltage U. ref and actual output voltage U o The difference is compared and recorded as A by the output of the proportional integral controller (PI controller). The AC voltage U after the rectifier bridge is... d Multiply by the scaling factor 1 / K to get B, then use a multiplier to combine A, B, and the coefficient K. m Multiplying them together yields the reference value I of the input current. ref The actual value of the inductor current and the reference current I are compared. ref The difference is compared and then passed through a current PI regulator to obtain the inductor voltage U. L The signal enters the pulse width modulation (PWM) generator, which calculates based on the inductor voltage expression to generate a PWM signal, which in turn controls the switching on and off of the power device.

[0003] In the aforementioned dual-loop PFC regulation system, the voltage loop is the outer loop, and its PI regulation bandwidth is relatively small, resulting in a slow response speed. When the bus voltage suddenly drops, it cannot quickly track the reference voltage, leading to an excessively long time for the bus to stabilize. This hinders the system's ability to quickly return to stable operation. Under severe operating conditions, an excessively long bus voltage drop can trigger overcurrent protection due to excessive AC current, causing a shutdown and impacting user experience. Summary of the Invention

[0004] This invention addresses the problem that existing PFC circuits cannot adjust in time when the bus voltage suddenly drops, which easily leads to overcurrent protection failures and shutdowns.

[0005] To address the aforementioned problems, this invention provides a PFC circuit control method, comprising: periodically acquiring the average value of the bus voltage during air conditioner operation; calculating the difference between adjacent average values ​​of the bus voltage; determining a compensated duty cycle based on an initial duty cycle, the difference, and a preset compensation coefficient; the compensated duty cycle being positively correlated with the difference; adjusting a PWM signal based on the compensated duty cycle; and controlling the on / off state of power devices based on the adjusted PWM signal.

[0006] The embodiment of the application compensates the duty cycle of the PWM signal based on the bus voltage reduction value, quickly adjusts the bus voltage to recover to a stable state by increasing the duty cycle of the PWM signal, thereby improving the stability of the system, reducing the probability of over-current protection due to bus voltage drop to a certain extent, reducing the fault shutdown condition, and improving the user experience.

[0007] Optionally, after the difference between the adjacent bus voltage average values is calculated, the method further comprises: determining the interval to which the difference belongs, and determining a corresponding preset compensation coefficient according to the interval to which the difference belongs; the preset compensation coefficient is positively correlated with the interval; and the determination of the compensated duty cycle according to the initial duty cycle, the difference and the preset compensation coefficient comprises: calculating the ratio of the difference to a target value corresponding to the interval, and calculating the product of the ratio and the preset compensation coefficient; the target value corresponding to the interval is an upper limit value, a lower limit value or a median value of the interval; and the sum of the initial duty cycle and the product is calculated to obtain the compensated duty cycle.

[0008] The embodiment of the application can divide the difference between the bus voltage average values into multiple intervals, and the same preset compensation coefficient is used for the difference between the bus voltage average values falling in a certain interval, and then the compensation value of the duty cycle is calculated by the preset compensation coefficient, the ratio of the above difference to the target value corresponding to the interval, so as to determine the compensation value according to the actual voltage drop condition, and realize instant and effective voltage stabilization control.

[0009] Optionally, the method further comprises: if the compensated duty cycle is greater than a maximum allowed value of the duty cycle, the compensated duty cycle is determined as the maximum allowed value of the duty cycle; and if the compensated duty cycle is less than a minimum allowed value of the duty cycle, the compensated duty cycle is determined as the minimum allowed value of the duty cycle.

[0010] The embodiment of the application provides the maximum and minimum values of the duty cycle, avoids excessive adjustment of the duty cycle, and improves the stability of the system.

[0011] Optionally, the interval to which the difference V err belongs comprises the following four intervals: if V err <V1, it is recorded as interval I; if V1≤V err ≤V2, it is recorded as interval II; if V2<V err ≤V3, it is recorded as interval III; and if V3<V err , it is recorded as interval IV.

[0012] The embodiment of the application provides a specific interval division mode of the bus voltage difference value, and can compensate the duty cycle differently according to the interval.

[0013] Optionally, the calculation formula of the compensated duty cycle is as follows: in interval I, no compensation is performed; in interval II, D=D1+V err / A3*B3; in interval IV, D=D1+V err / A3*B3; in interval IV, D=D1+V err / A3*B3; in interval IV, D=D1+V; wherein D is the compensated duty cycle, D1 is the initial duty cycle, A2, A3, A4 are target values corresponding to the interval, and B2, B3, B4 are preset compensation coefficients corresponding to the interval.

[0014] The embodiment of the present application provides a specific duty cycle calculation method, and the duty cycle can be directly compensated.

[0015] Optionally, the periodic acquisition of the bus voltage average value comprises: periodically acquiring a plurality of bus voltages in a target period, and calculating the bus voltage average value corresponding to the target period by using the plurality of bus voltages in the target period; and periodically acquiring a plurality of continuous bus voltage average values corresponding to the target period.

[0016] The embodiment of the present application provides a specific bus voltage average value calculation method, the duty cycle can be directly compensated, the DC bus voltage drop can be directly and quickly suppressed, and the stability of the system is improved.

[0017] Optionally, V1 is [15, 20], V2 is [25, 30], and V3 is [35, 45].

[0018] The embodiment of the present application provides a specific interval range, the duty cycle can be directly compensated, the DC bus voltage drop can be directly and quickly suppressed, and the stability of the system is improved.

[0019] The embodiment of the present application provides a PFC circuit control device, the device comprises: a voltage acquisition module, configured to periodically acquire a bus voltage average value during air conditioner operation; a difference calculation module, configured to calculate the difference between adjacent bus voltage average values; a duty cycle compensation module, configured to determine a compensated duty cycle according to an initial duty cycle, the difference and a preset compensation coefficient; the compensated duty cycle is positively correlated with the difference; and a power device control module, configured to adjust a PWM signal according to the compensated duty cycle, and control the on-off of a power device according to the adjusted PWM signal.

[0020] The embodiment of the present application provides a PFC circuit, comprising a bus voltage drop compensation control module, the bus voltage drop compensation control module is used for executing the above method.

[0021] The embodiment of the present application provides an air conditioner, comprising the above PFC circuit.

[0022] The embodiment of the present application provides a computer readable storage medium, the computer readable storage medium stores a computer program, and the computer program is read and run by a processor, and the above method is realized.

[0023] The PFC circuit control device for quickly compensating bus voltage drop, the air conditioner and the computer readable storage medium of the present application can achieve the same technical effects as the PFC circuit control method for quickly compensating bus voltage drop. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The improved Boost-PFC circuit structure diagram of an embodiment of the present application;

[0025] Figure 2 The schematic flow chart of the PFC circuit control method for quickly compensating bus voltage drop in an embodiment of the present application;

[0026] Figure 3 The gate voltage schematic diagram and current schematic diagram corresponding to the PWM signal based on the compensated duty ratio adjustment in an embodiment of the present application;

[0027] Figure 4 The structure schematic diagram of the PFC circuit control device for quickly compensating bus voltage drop in an embodiment of the present application.

[0028] REFERENCE SIGNS:

[0029] 401-voltage acquisition module; 402-difference calculation module; 403-duty ratio compensation module; 404-power device control module. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned purposes, characteristics and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail below with reference to the drawings.

[0031] The embodiment of the present application provides an improved Boost-PFC circuit, and a bus voltage drop compensation control module is added. Figure 1 The improved Boost-PFC circuit structure schematic diagram shown in the figure comprises a rectifier bridge D, an inductor L, a MOS tube S, a diode VD, a capacitor C1, a capacitor C2 and an adjusting system R. An alternating current provides a sinusoidal current (namely an AC input current) for the inductor L through the rectifier bridge D, the adjusting system R generates a PWM signal according to a reference voltage U ref and an actual output parameter, and controls the on-off of the MOS tube.

[0032] The above control process can be summarized as follows: a given reference voltage U ref and an actual output voltage Uo The difference is outputted as A through a voltage PI regulator; the AC voltage U after the rectifier bridge d is multiplied by a proportional coefficient 1 / K to obtain B; A, B and a coefficient K are multiplied by a multiplier to obtain m a reference value I of the input current ref The actual value of the inductor current and the reference current I ref are compared, and the difference is outputted as the inductor voltage U after a current PI regulator L is inputted into a PWM generator to calculate according to the inductor voltage expression; the signal is a PFC internal driving algorithm signal, which is a carrier of the PFC, and a modulation wave generates a PWM wave form through comparison, thereby controlling the on-off of the power device.

[0033] As shown in Figure 1 , a bus voltage drop compensation control module is added on the basis of the original topology structure, connected between the PWM generator and the MOS tube, and a duty cycle compensation control strategy is added after the PWM generation, which directly compensates the duty cycle, and finally the compensated PWM signal is transmitted to the MOS tube.

[0034] Figure 2 is a schematic flow chart of a PFC circuit control method for quickly compensating bus voltage drop in an embodiment of the application, which comprises the following steps:

[0035] S202, periodically obtaining the bus voltage average value during the operation of the air conditioner.

[0036] Optionally, a plurality of bus voltages are obtained at regular time intervals in each cycle, and the bus voltage average value of the corresponding cycle is obtained by calculating the plurality of bus voltages in each cycle.

[0037] Exemplarily, the bus voltage average value is calculated once every 10 ms during the actual operation of the air conditioner, and the bus voltage is recorded once every 150 us in a 10 ms cycle, and then the bus voltage average value of the cycle is obtained by calculating the average value. The average value of the bus voltage this time is V dc , and the average value of the bus voltage last time is V old , then the voltage drop value V err = V old -V dc .

[0038] S204, calculating the difference between adjacent bus voltage average values.

[0039] By calculating the difference between the two adjacent bus voltage average values, whether the bus voltage drop occurs can be detected, and then the corresponding duty cycle compensation is performed according to different voltage drop degrees.

[0040] S206, determine the compensated duty cycle according to the initial duty cycle, the difference value and a preset compensation coefficient.

[0041] The compensated duty cycle is positively correlated with the difference value, that is, the greater the bus voltage drop value, the higher the corresponding compensated duty cycle. The greater the bus voltage drop value, the longer the time required for the power device to be turned on, that is, the greater the required duty cycle, so as to achieve rapid compensation. The initial duty cycle is the duty cycle of the PWM signal output by the PWM generator.

[0042] S208, adjust the PWM signal according to the compensated duty cycle, and control the on-off of the power device according to the adjusted PWM signal. Illustratively, the power device is a MOS tube.

[0043] The PFC circuit control method for rapidly compensating bus voltage drop provided by the embodiment compensates the duty cycle of the PWM signal based on the bus voltage drop value, rapidly adjusts the bus voltage to recover to a stable state by increasing the duty cycle of the PWM signal, thereby improving the stability of the system, reducing the probability of overcurrent protection due to bus voltage drop to a certain extent, reducing the fault shutdown condition, and improving the user experience.

[0044] In consideration of the convenience of calculating the compensated duty cycle, the compensated duty cycle corresponding to the interval to which the difference value of the adjacent bus voltage average values belongs can be calculated. The difference value of the bus voltage average values falling in the interval adopts the same preset compensation coefficient. Then, the compensation value of the duty cycle is calculated by the ratio of the preset compensation coefficient, the difference value and the target value corresponding to the interval, so as to determine the compensation value according to the actual voltage drop condition, and realize instant and effective voltage stabilization control.

[0045] Based on this, after S104, the method further includes the following steps: determining the interval to which the difference value belongs, and determining the corresponding preset compensation coefficient according to the interval to which the difference value belongs. The preset compensation coefficient is positively correlated with the interval, that is, the greater the value of the interval, the higher the corresponding preset compensation coefficient. Further, S106 can be performed in the following manner: calculating the ratio of the difference value and the target value corresponding to the interval, and calculating the product of the ratio and the preset compensation coefficient; calculating the sum of the initial duty cycle and the product, thereby obtaining the compensated duty cycle. Therefore, the duty cycle can be compensated differently according to the interval to which the difference value belongs. The target value corresponding to the interval is the upper limit value, the lower limit value or the median value of the interval.

[0046] Illustratively, the interval to which the difference value V err belongs can be divided into the following four intervals: if V err <V1, it is called interval I; if V1≤V err ≤V2, it is called interval II; if V2<Verr ≤ V3, denoted as interval III; if V3 < V err , denoted as interval IV. The calculation formula of the compensated duty ratio is as follows:

[0047] In interval I, no compensation is performed;

[0048] In interval II, D = D1 + V err / A2*B2;

[0049] In interval III, D = D1 + V err / A3*B3;

[0050] In interval IV, D = D1 + V err / A4*B4;

[0051] Wherein, D is the compensated duty ratio, D1 is the initial duty ratio, A2, A3, A4 are target values corresponding to the interval, and B2, B3, B4 are preset compensation coefficients corresponding to the interval. If the carrier cycle is TS, the turn-on time is T on , and the turn-off time is T off , then the duty ratio D = T on / T s .

[0052] As described above, B2, B3, and B4 increase in turn. As the bus voltage drops from normal to drop, the greater the drop, the easier it is to overcurrent protection, and by directly compensating the duty ratio, the time of closing the power device can be quickly increased, thereby rapidly increasing the bus voltage. The greater the drop value, the greater the compensation coefficient. The above-mentioned preset compensation coefficient, if the value is too small, the voltage boosting effect is obvious, and if the value is too large, it will cause the bus to overshoot, which needs to be adjusted according to the actual control system, and appropriate compensation coefficients are obtained by taking into account the above two factors.

[0053] Since the duty ratio D of the MOS tube is limited by the maximum value D max and the minimum value D min : D max >D>D min , the embodiment also provides an assignment step compatible with the maximum value and the minimum value, which avoids excessive adjustment of the duty ratio. The above-mentioned method further comprises: if the obtained compensated duty ratio is greater than the maximum allowed duty ratio, the compensated duty ratio is determined as the maximum allowed duty ratio; and if the obtained compensated duty ratio is less than the minimum allowed duty ratio, the compensated duty ratio is determined as the minimum allowed duty ratio. Illustratively, if D < D min , let D = D min ; and if D > D max , let D = D max .

[0054] Optionally, V1 is in the range of [15, 20], V2 is in the range of [25, 30], and V3 is in the range of [35, 45].

[0055] For example, according to the value of V err , the range is divided into four areas: when V err <20, it is called area I; when 20≤V err ≤30, it is called area II; when 30<V err ≤40, it is called area III; and when 40<V err , it is called area IV. In the calculation of the compensated duty cycle, the target value of each area is the lower limit value of the area, i.e. A2, A3, A4 are respectively 20, 30, and 40. B2, B3, B4 are respectively 0.2%, 0.3%, and 0.5%.

[0056] In area I, no compensation is made to the duty cycle;

[0057] In area II, compensation is made to the duty cycle, where D1 is the uncompensated duty cycle, and D=D1+V err / 20*0.2%;

[0058] In area III, compensation is made to the duty cycle, where D1 is the uncompensated duty cycle, and D=D1+V err / 30*0.3%;

[0059] In area IV, compensation is made to the duty cycle, where D1 is the uncompensated duty cycle, and D=D1+V err / 40*0.5%.

[0060] Finally, the compensated duty cycle is limited, when D<D min , D=D min ; when D>D max , D=D max .

[0061] Figure 3 The schematic diagram of the gate voltage and the current corresponding to the PWM signal adjusted based on the compensated duty cycle is shown. In the Figure 3 , the current i L before compensation and the current i 期望 after compensation are shown. It can be obviously seen that the current i L before compensation has a significant surge, while the current i 期望 after compensation is smoother.

[0062] Compared with the prior PFC average current method, the method provided in the embodiment can quickly adjust the bus voltage to recover to a stable state in a harsh condition, such as when the bus voltage suddenly drops or the bus voltage suddenly drops due to a sudden increase in load, improves the stability of the system, and to a certain extent, reduces the probability of over-current protection caused by bus voltage drop.

[0063] Figure 4 is a structural schematic diagram of a PFC circuit control device for quickly compensating for bus voltage drop in an embodiment of the application, the device comprising:

[0064] The voltage acquisition module 401 is configured to periodically acquire bus voltage average values during air conditioner operation.

[0065] The difference calculation module 402 is configured to calculate the difference between adjacent bus voltage average values.

[0066] The duty cycle compensation module 403 is configured to determine a compensated duty cycle according to an initial duty cycle, the difference, and a preset compensation coefficient; the compensated duty cycle is positively correlated with the difference.

[0067] The power device control module 404 is configured to adjust a PWM signal according to the compensated duty cycle, and control the on-off of a power device according to the adjusted PWM signal.

[0068] The PFC circuit control device for quickly compensating for bus voltage drop provided in the embodiment compensates for the duty cycle of a PWM signal based on the bus voltage drop value, quickly adjusts the bus voltage to recover to a stable state by increasing the duty cycle of the PWM signal, thereby improving the stability of the system, to a certain extent, reducing the probability of over-current protection caused by bus voltage drop, reducing the situation of fault shutdown, and improving the user experience.

[0069] Optionally, the device further comprises an interval determination module configured to determine the interval to which the difference belongs, and determine the corresponding preset compensation coefficient according to the interval to which the difference belongs; the preset compensation coefficient is positively correlated with the interval; the duty cycle compensation module is specifically configured to calculate the ratio of the difference to a target value corresponding to the interval, and calculate the product of the ratio and the preset compensation coefficient; the target value corresponding to the interval is the upper limit value, the lower limit value, or the median value of the interval; calculate the sum of the initial duty cycle and the product to obtain the compensated duty cycle.

[0070] Optionally, the device further comprises a duty cycle limiting module configured to: if the obtained compensated duty cycle is greater than a maximum allowed duty cycle, determine the compensated duty cycle as the maximum allowed duty cycle; and if the obtained compensated duty cycle is less than a minimum allowed duty cycle, determine the compensated duty cycle as the minimum allowed duty cycle.

[0071] Optionally, the difference V err belongs to one of the following four intervals: if V err <V1, denoted as interval I; if V1≤V err ≤V2, denoted as interval II; if V2<V err ≤V3, denoted as interval III; and if V3<V err , denoted as interval IV.

[0072] Optionally, the compensated duty cycle is calculated according to the following formula:

[0073] In interval I, no compensation is performed.

[0074] In interval II, D=D1+V err / A2*B2.

[0075] In interval III, D=D1+V err / A3*B3.

[0076] In interval IV, D=D1+V err / A4*B4.

[0077] wherein D is the compensated duty cycle, D1 is an initial duty cycle, A2, A3 and A4 are target values corresponding to the intervals, and B2, B3 and B4 are preset compensation coefficients corresponding to the intervals.

[0078] Optionally, the voltage obtaining module is specifically configured to: obtain multiple bus voltages at a target period in a timely manner, and calculate a bus voltage average value corresponding to the target period based on the multiple bus voltages at the target period; and periodically obtain bus voltage average values corresponding to multiple continuous target periods.

[0079] Optionally, V1 is set to [15, 20], V2 is set to [25, 30], and V3 is set to [35, 45].

[0080] Embodiments of the present application provide a PFC circuit, which comprises a bus voltage drop compensation control module configured to perform the above method.

[0081] Embodiments of the present application provide an air conditioner, which comprises the above PFC circuit.

[0082] The embodiment of the present application further provides a computer readable storage medium, which stores a computer program, and the computer program is read and run by a processor to implement the method provided by the above embodiment and achieve the same technical effects. To avoid repetition, details are not described herein. The computer readable storage medium is, for example, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0083] Of course, those skilled in the art can understand that all or part of the processes in the above method embodiments can be completed by instructing a control device through a computer, and the program can be stored in a computer readable storage medium. The program can include the processes of the above method embodiments when executed, and the storage medium can be a memory, a magnetic disk, an optical disk, etc.

[0084] Although the present application is disclosed as above, the present application is not limited to this. Any person skilled in the art can make various modifications and changes without departing from the spirit and scope of the present application, and the protection scope of the present application should be defined by the scope defined by the claims.

[0085] Finally, it should be noted that, in this document, the terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or device including the element.

[0086] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts between various embodiments can be referred to each other. For the PFC circuit control device, PFC circuit and air conditioner disclosed by the embodiments for quickly compensating bus voltage drop, since it corresponds to the PFC circuit control method for quickly compensating bus voltage drop disclosed by the above embodiments, the description is relatively simple, and the relevant parts can be referred to the method part.

[0087] Although the present application has been disclosed with reference to the above embodiments, the application is not limited to the above embodiments. It will be apparent to those skilled in the art that various modifications and changes can be made thereto without departing from the spirit and scope of the application. The scope of the application should be limited only by the appended claims.

Claims

1. A PFC circuit control method characterized by, The method comprises: During the operation of the air conditioner, periodically acquiring bus voltage average values; calculating the difference between the bus voltage average values of adjacent periods; determining a compensated duty cycle according to an initial duty cycle, the difference, and a preset compensation coefficient; the compensated duty cycle is positively correlated with the difference; adjusting a PWM signal according to the compensated duty cycle, and controlling the on-off of a power device according to the adjusted PWM signal; after the calculation of the difference between the bus voltage average values of adjacent periods, the method further comprises: determining the interval to which the difference belongs, and determining the corresponding preset compensation coefficient according to the interval to which the difference belongs; the preset compensation coefficient is positively correlated with the interval; the determination of the compensated duty cycle according to the initial duty cycle, the difference, and the preset compensation coefficient comprises: calculating the ratio of the difference to the target value corresponding to the interval, and calculating the product of the ratio and the preset compensation coefficient; the target value corresponding to the interval is the upper limit value, the lower limit value, or the median value of the interval; calculating the sum of the initial duty cycle and the product to obtain the compensated duty cycle.

2. The method of claim 1, wherein, The method further comprises: if the compensated duty cycle obtained is greater than the maximum allowed duty cycle, the compensated duty cycle is determined as the maximum allowed duty cycle; if the compensated duty cycle obtained is less than the minimum allowed duty cycle, the compensated duty cycle is determined as the minimum allowed duty cycle.

3. The method of claim 1, wherein, The difference value V err The interval of the application includes the following 4 intervals: If V err < V1, it is denoted as interval I; if V1 ≤ V err ≤ V2, it is denoted as interval II; if V2 < V err ≤ V3, it is denoted as interval III; if V3 < V err , it is denoted as interval IV.

4. The method of claim 3, wherein, The calculation formula of the compensated duty cycle is as follows: no compensation is performed in interval I; In interval II, D = D1 + V err / A2*B2; In interval III, D = D1+V err / A3*B3; Within interval IV, D = D1 + V err / A4*B4; wherein D is the compensated duty cycle, D1 is the initial duty cycle, A2, A3, and A4 are target values corresponding to the interval, and B2, B3, and B4 are preset compensation coefficients corresponding to the interval.

5. The method according to any one of claims 1 to 4, characterized in that, The periodic acquisition of bus voltage average values comprises: acquiring multiple bus voltages at a target period, and calculating the bus voltage average value corresponding to the target period from the multiple bus voltages at the target period; periodically acquiring multiple continuous bus voltage average values corresponding to the target period.

6. The method of claim 3, wherein, V1 is valued at [15, 20], V2 is valued at [25, 30], and V3 is valued at [35, 45].

7. A PFC circuit control device characterized by comprising: The device comprises: a voltage acquisition module configured to periodically acquire bus voltage average values during the operation of the air conditioner; a difference calculation module configured to calculate the difference between the bus voltage average values of adjacent periods; a duty cycle compensation module configured to determine a compensated duty cycle according to an initial duty cycle, the difference, and a preset compensation coefficient; the compensated duty cycle is positively correlated with the difference; a power device control module configured to adjust a PWM signal according to the compensated duty cycle, and control the on-off of a power device according to the adjusted PWM signal; an interval determination module configured to determine the interval to which the difference belongs, and determine the corresponding preset compensation coefficient according to the interval to which the difference belongs; the preset compensation coefficient is positively correlated with the interval; The duty cycle compensation module is configured to calculate a ratio of the difference value to a target value corresponding to the interval, and calculate a product of the ratio and a preset compensation coefficient; the target value corresponding to the interval is an upper limit value, a lower limit value or a median value of the interval; and calculate a sum of an initial duty cycle and the product to obtain a compensated duty cycle.

8. A PFC circuit, characterized by, The power supply system comprises a bus voltage drop compensation control module configured to perform the method according to any one of claims 1-6.

9. An air conditioner characterized by comprising: The PFC circuit comprises the PFC circuit according to claim 8.

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