PFC circuit control method and apparatus, and electronic device

Abstract

The invention provides a PFC circuit control method and apparatus, and an electronic device. The method comprises the steps of determining that an inductive current of a PFC circuit is 0; a negative current compensation value is calculated according to the input voltage instantaneous value and a voltage product, the voltage product is a product of the output voltage and a voltage segmentation coefficient, and the voltage segmentation coefficient is calculated according to the first current compensation value, a preset second current compensation value, preset delay duration, the output voltage and an inductance value of an inductor in the PFC circuit; according to the negative current compensation value, the inductance value, the output voltage and the input voltage instantaneous value, extra conduction duration is calculated; and a synchronous rectifier tube in the PFC circuit is controlled to be switched on in the extra switching-on duration and generate negative current. According to the invention, the negative current compensation value is calculated according to the product of the input voltage instantaneous value and the voltage, the additional conduction duration of the PFC circuit is further calculated, and the PFC circuit realizes high-efficiency negative current compensation by controlling the additional conduction duration of the synchronous rectifier tube in the PFC circuit.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and in particular to a control method, apparatus, and electronic device for a PFC circuit. Background Technology

[0002] With the development of power electronics technology, TCM (Triangular Current Mode) controlled totem-pole PFC (Power Factor Correction) circuits are widely used in communication power supplies, automotive power supplies, and other fields. In TCM control, when the inductor current input to the PFC circuit is determined to be 0, the synchronous rectifier tube of the PFC circuit will continue to conduct for an additional period of time to generate a negative current in order to achieve ZVS (Zero Voltage Switching). If the negative current generated during this conduction time is too small, it will cause the main tube in the PFC circuit to be hard-turned on, resulting in stress and electromagnetic interference problems. If the negative current generated during this conduction time is too large, it will cause power loss and reduced efficiency. Therefore, the extra conduction time of the synchronous rectifier tube is particularly important in the control of the PFC circuit.

[0003] In the existing technology, the PFC circuit is mainly controlled by fixed negative current compensation control. A fixed negative current compensation value is preset, and the additional conduction time of the synchronous rectifier is calculated through the preset negative current compensation value. However, since the negative current compensation value is a fixed value, it will cause the negative current compensation to be too small, resulting in hard turn-on of the main tube in the PFC circuit, or cause the negative current compensation to be too large, resulting in power loss and low efficiency. Summary of the Invention

[0004] This invention provides a control method, device, and electronic device for a PFC circuit, which solves the problem in the prior art where the negative current compensation value is a fixed value, resulting in excessive or insufficient negative current compensation.

[0005] In a first aspect, embodiments of this application provide a control method for a PFC circuit, the method comprising:

[0006] The inductor current of the PFC circuit is determined to be 0.

[0007] The negative current compensation value is calculated based on the instantaneous value of the input voltage and the magnitude of the voltage product. The voltage product is the product of the output voltage and the voltage segmentation coefficient. The voltage segmentation coefficient is calculated based on the first current compensation value, the preset second current compensation value, the preset delay time, the output voltage, and the inductance value of the inductor in the PFC circuit. The first current compensation value is calculated based on the absolute value of the difference between the negative current value at the zero-crossing point of the input voltage and the negative current value at the peak point of the input voltage under rated operating conditions without negative current compensation.

[0008] The additional conduction time is calculated based on the negative current compensation value, the inductance value, the output voltage, and the instantaneous input voltage value.

[0009] The synchronous rectifier in the PFC circuit is controlled to conduct during the additional conduction period and generate a negative current.

[0010] In one possible implementation, calculating the negative current compensation value based on the instantaneous value of the input voltage and the magnitude of the voltage product includes:

[0011] If the instantaneous value of the input voltage is less than or equal to the voltage product, then the negative current compensation value is 0;

[0012] If the instantaneous value of the input voltage is greater than the voltage product, then the negative current compensation value is calculated based on the output voltage, the instantaneous value of the input voltage, the inductance value, the delay duration, the first current compensation value, and the second current compensation value.

[0013] In one possible implementation, calculating the negative current compensation value based on the output voltage, the instantaneous value of the input voltage, the inductance value, the delay duration, the first current compensation value, and the second current compensation value includes:

[0014] Calculate the first difference between the instantaneous values ​​of the output voltage and the input voltage;

[0015] Calculate the first ratio between the first difference and the inductance value;

[0016] Calculate the first product of the first ratio and the delay duration;

[0017] Calculate the absolute value of the difference between the first product and the first current compensation value;

[0018] The difference between the absolute value and the second current compensation value is taken as the negative current compensation value.

[0019] In one possible implementation, the voltage segmentation coefficient is calculated in the following manner:

[0020] Calculate the second difference between the first current compensation value and the second current compensation value, and calculate the second product of the delay duration and the output voltage;

[0021] Calculate the second ratio of the second difference to the second product, and multiply the second ratio by the inductance value to obtain the third product;

[0022] The difference between 1 and the third product is used as the voltage segmentation coefficient.

[0023] In one possible implementation, the first current compensation value is calculated in the following manner:

[0024] Calculate the first absolute value of the difference between the negative current value at the zero-crossing point of the input voltage and the negative current value at the peak point of the input voltage;

[0025] Calculate the third difference between the instantaneous values ​​of the output voltage and the input voltage, and the third ratio of the third difference to the inductance value;

[0026] Calculate the fourth product of the third ratio and the delay duration;

[0027] The sum of twice the first absolute value and the fourth product is taken as the first current compensation value.

[0028] In one possible implementation, calculating the additional on-time based on the negative current compensation value, the inductance value, the output voltage, and the instantaneous input voltage value includes:

[0029] Calculate the second product of the inductance value and the negative current compensation value, and calculate the second difference between the instantaneous values ​​of the output voltage and the input voltage;

[0030] The ratio of the second product to the second difference is used as the additional conduction time.

[0031] In a second aspect, this application provides an electronic device, comprising: a processor; and a memory for storing processor-executable instructions; wherein the processor implements the steps of the method described in any of the first aspects by executing the executable instructions.

[0032] Thirdly, this application provides a control device for a PFC circuit, the device comprising:

[0033] A determination module is used to determine that the inductor current of the PFC circuit is 0;

[0034] The calculation module is used to calculate the negative current compensation value based on the instantaneous value of the input voltage and the magnitude of the voltage product. The voltage product is the product of the output voltage and a voltage segmentation coefficient, which is calculated based on a first current compensation value, a preset second current compensation value, a preset delay time, the output voltage, and the inductance value of the inductor in the PFC circuit. The first current compensation value is calculated based on the absolute value of the difference between the negative current value at the zero-crossing point of the input voltage and the negative current value at the peak value of the input voltage under rated operating conditions without negative current compensation. The module also calculates an additional conduction time based on the negative current compensation value, the inductance value, the output voltage, and the instantaneous value of the input voltage.

[0035] The synchronous rectifier in the PFC circuit is controlled to conduct during the additional conduction period and generate a negative current.

[0036] In one possible implementation, the computing module is specifically used for:

[0037] If the instantaneous value of the input voltage is less than or equal to the voltage product, then the negative current compensation value is 0;

[0038] If the instantaneous value of the input voltage is greater than the voltage product, then the negative current compensation value is calculated based on the output voltage, the instantaneous value of the input voltage, the inductance value, the delay duration, the first current compensation value, and the second current compensation value.

[0039] In one possible implementation, the computing module is specifically used for:

[0040] Calculate the first difference between the instantaneous values ​​of the output voltage and the input voltage;

[0041] Calculate the first ratio between the first difference and the inductance value;

[0042] Calculate the first product of the first ratio and the delay duration;

[0043] Calculate the absolute value of the difference between the first product and the first current compensation value;

[0044] The difference between the absolute value and the second current compensation value is taken as the negative current compensation value.

[0045] The beneficial effects of this invention are as follows:

[0046] This application provides a control method, apparatus, and electronic device for a PFC circuit. The method includes: determining that the inductor current of the PFC circuit is 0; calculating a negative current compensation value based on the instantaneous value of the input voltage and the magnitude of the voltage product, wherein the voltage product is the product of the output voltage and the voltage segmentation coefficient, the voltage segmentation coefficient is calculated based on a first current compensation value, a preset second current compensation value, a preset delay time, the output voltage, and the inductance value of the inductor in the PFC circuit; the first current compensation value is calculated based on the absolute value of the difference between the negative current value at the zero-crossing point of the input voltage and the negative current value at the peak point of the input voltage under rated operating conditions without negative current compensation; calculating an additional conduction time based on the negative current compensation value, the inductance value, the output voltage, and the instantaneous value of the input voltage; and controlling the synchronous rectifier in the PFC circuit to conduct during the additional conduction time and generate a negative current. This application calculates the negative current compensation value based on the instantaneous value of the input voltage and the magnitude of the voltage product, and then calculates the additional conduction time of the PFC circuit. By controlling the additional conduction time of the synchronous rectifier in the PFC circuit, the PFC circuit can achieve high-efficiency negative current compensation. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 A structural diagram of a PFC circuit provided in an embodiment of this application;

[0049] Figure 2 A flowchart of a control method for a PFC circuit provided in an embodiment of this application;

[0050] Figure 3 A flowchart illustrating another control method for a PFC circuit provided in an embodiment of this application;

[0051] Figure 4 This is a schematic diagram of a control method for a PFC circuit according to an embodiment of this application;

[0052] Figure 5 A schematic diagram of another control method for a PFC circuit provided in an embodiment of this application;

[0053] Figure 6 A schematic diagram of another control method for a PFC circuit provided in an embodiment of this application;

[0054] Figure 7 A flowchart illustrating another control method for a PFC circuit provided in an embodiment of this application;

[0055] Figure 8 A flowchart illustrating another control method for a PFC circuit provided in an embodiment of this application;

[0056] Figure 9 A flowchart illustrating another control method for a PFC circuit provided in an embodiment of this application;

[0057] Figure 10 A schematic diagram of another control method for a PFC circuit provided in an embodiment of this application;

[0058] Figure 11 A schematic diagram of another control method for a PFC circuit provided in an embodiment of this application;

[0059] Figure 12 A schematic diagram of a control device for a PFC circuit provided in an embodiment of this application;

[0060] Figure 13 This is a schematic diagram of an electronic device provided in an embodiment of this application. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0062] With the development of power electronics technology, TCM-controlled totem-pole PFC circuits are widely used in communication power supplies, automotive power supplies, and other fields, such as... Figure 1 The diagram shows the structure of a PFC circuit. S1 and S2 are high-frequency transistors, S3 and S4 are low-frequency transistors, D1, D2, D3, and D4 are diodes, C1, C2, C3, and C4 are capacitors, and L is an inductor. During the positive half-cycle of the input voltage, S1 acts as the synchronous rectifier, and during the negative half-cycle, S2 acts as the synchronous rectifier. In a TCM-controlled PFC circuit, when the inductor current of the PFC circuit is determined to be zero, the synchronous rectifier will continue to conduct for an additional period to generate a negative current, achieving zero-voltage switching (ZVS). If the negative current generated during this conduction time is too small, it will cause the main conductor in the PFC circuit to be hard-turned on, resulting in stress and electromagnetic interference. If the negative current generated during this conduction time is too large, it will cause power loss and reduced efficiency. Therefore, the additional conduction time of the synchronous rectifier is particularly important in the control of the PFC circuit.

[0063] In the existing technology, the PFC circuit is mainly controlled by fixed negative current compensation control. A fixed negative current compensation value is preset, and the additional conduction time of the synchronous rectifier is calculated through the preset negative current compensation value. However, since the negative current compensation value is a fixed value, it will cause the negative current compensation to be too small, resulting in hard turn-on of the main tube in the PFC circuit, or cause the negative current compensation to be too large, resulting in power loss and low efficiency.

[0064] Based on the above problems, embodiments of this application provide a control method for a PFC circuit, such as... Figure 2 The diagram shown is a flowchart of a control method for a PFC circuit provided in an embodiment of this application. The steps of the method are as follows:

[0065] S201. Determine that the inductor current of the PFC circuit is 0;

[0066] S202. Calculate the negative current compensation value based on the instantaneous input voltage value Vin(t) and the voltage product. The voltage product is the product of the output voltage Vpfc and the voltage segmentation coefficient K. The voltage segmentation coefficient K is calculated based on the first current compensation value I_zcd, the preset second current compensation value I_offest, the preset delay time tzcd_set, the output voltage Vpfc, and the inductance value Lpfc of the inductor in the PFC circuit. The first current compensation value I_zcd is calculated based on the absolute value of the difference between the negative current value at the zero-crossing point of the input voltage and the negative current value at the peak point of the input voltage under rated operating conditions without negative current compensation.

[0067] S203. Calculate the additional conduction time based on the negative current compensation value, inductance value Lpfc, output voltage Vpfc, and instantaneous input voltage Vin(t).

[0068] S204 controls the synchronous rectifier in the PFC circuit to conduct for an additional period of time and generate a negative current.

[0069] This application provides a control method for a PFC circuit. The method includes: first, determining that the inductor current of the PFC circuit is 0; then, calculating a negative current compensation value based on the magnitude of the instantaneous input voltage value Vin(t) and the voltage product, wherein the voltage product is the product of the output voltage Vpfc and the voltage segmentation coefficient K, the voltage segmentation coefficient K is calculated based on a first current compensation value I_zcd, a preset second current compensation value I_offest, a preset delay time tzcd_set, the output voltage Vpfc, and the inductance value Lpfc of the inductor in the PFC circuit; the first current compensation value I_zcd is calculated based on the absolute value of the difference between the negative current value at the zero-crossing point of the input voltage and the negative current value at the peak point of the input voltage under rated operating conditions without negative current compensation; and calculating an additional conduction time based on the negative current compensation value, the inductance value Lpfc, the output voltage Vpfc, and the instantaneous input voltage value Vin(t); finally, controlling the synchronous rectifier in the PFC circuit to conduct during the additional conduction time and generate a negative current. This application calculates the negative current compensation value based on the instantaneous value of the input voltage and the magnitude of the voltage product, and then calculates the additional conduction time of the PFC circuit. By controlling the additional conduction time of the synchronous rectifier in the PFC circuit, the PFC circuit can achieve high-efficiency negative current compensation.

[0070] It should be noted that the preset delay duration tzcd_set is obtained based on the hardware delay and software delay of the zero-crossing detection circuit corresponding to the compensated circuit under the target operating condition.

[0071] For example, the delay duration tzcd_set can be 400ns. This delay duration tzcd_set includes the signal detection delay of the hardware comparator chip in the zero-crossing detection circuit, the filter delay of signal transmission, and the delay from signal processing to the output result. The delay duration tzcd_set is the total delay of the entire signal chain.

[0072] Furthermore, when the instantaneous value of the input voltage Vin(t) is less than or equal to the voltage product, the negative current compensation value is 0;

[0073] When the instantaneous input voltage Vin(t) is greater than the voltage product, the negative current compensation value is calculated based on the output voltage Vpfc, the instantaneous input voltage Vin(t), the inductance value Lpfc, the delay time tzcd_set, the first current compensation value I_zcd, and the second current compensation value I_offest.

[0074] Wherein, the instantaneous input voltage Vin(t) is the instantaneous input voltage of the PFC circuit, the output voltage Vpfc is the output voltage of the PFC circuit, and the inductance value Lpfc is the inductance value of the PFC circuit. The calculation of the first current compensation value I_zcd and the second current compensation value I_offest is described in detail below:

[0075] In one embodiment, such as Figure 3 As shown, the first current compensation value I_zcd is calculated in the following way:

[0076] S301. Calculate the first absolute value Ierr of the difference between the negative current value I1 at the zero crossing of the input voltage and the negative current value I2 at the peak of the input voltage;

[0077] Specifically, |I1-I2|=Ierr, where I1 is the negative current at the zero-crossing point of the input voltage of the PFC circuit under rated operating conditions, and I2 is the negative current at the peak point of the input voltage of the PFC circuit under rated operating conditions.

[0078] In a specific embodiment, the rated operating condition refers to the working state where the input is 220V and the output is 420V. For example, when the PFC circuit is operating with an input of 220V and an output of 420V, the negative current at 0V is -0.756A and the negative current at the peak is -0.196A. The calculated Ierr = |I1-I2| = |-0.756-(-0.196)| = 0.56A, that is, the first absolute value Ierr is 0.56A.

[0079] S302. Calculate the third difference between the output voltage Vpfc and the instantaneous value of the input voltage Vin(t), and the third ratio of the third difference to the inductance value Lpfc.

[0080] Specifically,

[0081] S303. Calculate the fourth product of the third ratio and the delay duration tzcd_set;

[0082] Specifically,

[0083] S304. Take the sum of twice the first absolute value Ierr and the fourth product as the first current compensation value I_zcd.

[0084] It should be noted that the first current compensation value I_zcd is calculated when the absolute value of the difference between the fourth product and the first current compensation value I_zcd is twice the first absolute value Ierr. At that time, the value of the first current compensation value I_zcd is obtained.

[0085] In practical applications, the calculated I_zcd yields two values, one negative and one positive. This application uses the positive value for I_zcd. That is, the sum of twice the first absolute value Ierr and the fourth product is taken as the first current compensation value I_zcd.

[0086] In a specific embodiment, for example, when the instantaneous input voltage Vin(t) is 311V, the output voltage Vpfc is 420V, the inductance value Lpfc is 110Uh, the delay time tzcd_set is 400ns, and the first absolute value Ierr is 0.56A, The calculated value of the first current compensation value I_zcd is 1.5A.

[0087] In a specific embodiment, such as Figure 4 As shown, the first current compensation value I_zcd is equivalent to compensating the initial negative current of the PFC circuit under the target operating condition, resulting in the compensation negative current Iv_fill. It should be noted that the compensation negative current Iv_fill is equivalent to doubling the compensation value of the initial negative current, so that the negative current exhibits a convex shape in the time domain.

[0088] The initial negative current refers to the negative current generated through resonance when the synchronous rectifier of the PFC circuit is directly turned off after the inductor current of the PFC circuit is determined to be zero. In other words, the initial negative current refers to the current before negative current compensation is performed by the PFC circuit. (The term "compensation for negative current" is used to describe the process of filling in the gaps in the negative current.)

[0089]

[0090] In addition, such as Figure 5 As shown, from top to bottom, the initial negative current, the critical negative current control mode controls the PFC circuit to achieve the critical current Iv_min for ZVS, and the compensation negative current Iv_fill. Therefore, this application also needs to perform shift compensation on the compensation negative current Iv_fill.

[0091] It should be noted that the critical current Iv_min that enables ZVS under the control of the PFC circuit in the critical negative current control mode is calculated based on the minimum additional negative conduction current Isr_off_min, the output voltage Vpfc, the instantaneous value of the input voltage Vin(t), and the impedance Zn of the PFC circuit. Among them, the minimum additional negative conduction current Isr_off_min is calculated based on the output voltage Vpfc, the instantaneous value of the input voltage Vin(t), and the impedance Zn of the PFC circuit.

[0092] This application calculates the critical current Iv_min in advance and stores it in memory. When it is necessary to shift the compensation negative current Iv_fill, the shift compensation is performed based on the pre-stored critical current Iv_min and the calculated compensation negative current Iv_fill.

[0093] Specifically, through The minimum additional negative conduction current Isr_off_min is calculated.

[0094] And through The critical compensation current Iv_min was calculated.

[0095] Specifically, the difference between the critical compensation current Iv_min and the negative compensation current Iv_fill is used as the second current compensation value I_offest, and the negative compensation current Iv_fill is shifted and compensated based on the second current compensation value I_offest.

[0096] In a specific embodiment, if the instantaneous input voltage Vin(t) at the target time is known to be 311V, the output voltage Vpfc to be 420V, the inductance value Lpfc to be 110Uh, the delay time tzcd_set to be 400ns, and taking the first absolute value Ierr at the peak of the input voltage to be 0.56A and the critical negative current Iv_min to be -0.61A as an example, when the following conditions are met... When the initial negative current I_zcd is 1.5A, it is used to compensate for the initial negative current, resulting in a compensated negative current Iv_fill. The second current compensation value is then set to I_offest = Iv_min - Iv_fill. For example, when the initial negative current of the circuit being compensated is 0.196A, Iv_fill = -(I_zcd + 0.196) = -(1.5 + 0.196) = -1.696A, and I_offest = Iv_min - Iv_fill = 1.086. This allows the second current compensation value I_offest to shift the compensated negative current Iv_fill, resulting in a shifted negative current.

[0097] In one embodiment, it is also necessary to optimize the compensation of the translational negative current based on the segmentation coefficient K, such as... Figure 6 As shown, if the segmentation coefficient K is set to 0.5 for optimization compensation, a sudden change will occur at Vin(t) = 0.5Vpfc. Therefore, the segmentation coefficient K needs to be calculated based on the first current compensation value I_zcd, the second current compensation value I_offest, the delay time tzcd_set, the output voltage Vpfc, and the inductance value Lpfc.

[0098] It should be noted that negative current compensation is not required when Vin(t) < 0.5Vpfc, but is required when Vin(t) > 0.5Vpfc. That is, when K is 0.5, the negative current will suddenly change at Vin(t) = 0.5Vpfc. The segmentation coefficient K is calculated by using the first current compensation value I_zcd, the second current compensation value I_offest, the delay time tzcd_set, the output voltage Vpfc, and the inductance value Lpfc, which can achieve a smooth transition of the negative current at Vin = K × Vpfc.

[0099] Specifically, such as Figure 7 As shown, the voltage segmentation factor K is calculated in the following way:

[0100] S701, calculate the second difference between the first current compensation value I_zcd and the second current compensation value I_offest, and calculate the second product of the delay time tzcd_set and the output voltage Vpfc;

[0101] Specifically, the second difference = I_zcd - I_offset; the second product = tzcd_set × Vpfc.

[0102] S702. Calculate the second ratio of the second difference I_zcd-I_offest to the second product tzcd_set×Vpfc, and multiply the second ratio by the inductance value Lpfc to obtain the third product;

[0103] Specifically,

[0104] S703. The difference between 1 and the third product is used as the voltage segmentation coefficient.

[0105] Specifically,

[0106] In one embodiment, if the instantaneous input voltage Vin(t) is greater than the voltage product, then a negative current compensation value is calculated based on the output voltage Vpfc, the instantaneous input voltage Vin(t), the inductance value Lpfc, the delay time tzcd_set, the first current compensation value I_zcd, and the second current compensation value I_offset. Here, the voltage product is the product of the output voltage and the voltage segmentation coefficient. Figure 8 As shown, the specific steps are as follows:

[0107] S801. Calculate the first difference between the output voltage Vpfc and the instantaneous value of the input voltage Vin(t);

[0108] Specifically, the first difference is (Vpfc - Vin(t)).

[0109] S802, Calculate the first ratio between the first difference and the inductance value Lpfc;

[0110] Specifically,

[0111] S803. Calculate the first product of the first ratio and the delay duration tzcd_set;

[0112] Specifically,

[0113] S804. Calculate the second absolute value of the difference between the first product and the first current compensation value I_zcd;

[0114] Specifically,

[0115] S805. The difference between the absolute value and the second current compensation value I_offest is taken as the negative current compensation value Iv_cmp_K.

[0116] Specifically,

[0117] In other words, when the instantaneous value of the input voltage is less than or equal to the product of the output voltage and the voltage segmentation coefficient, the negative current compensation value Iv_cmp_K is 0; when the instantaneous value of the input voltage is greater than the product of the output voltage and the voltage segmentation coefficient, the negative current compensation value Iv_cmp_K is...

[0118]

[0119] Since it is known from the above calculations Therefore, the calculated negative current compensation value Iv_cmp_K can be:

[0120]

[0121] In one embodiment, such as Figure 9 As shown, the additional on-time is calculated based on the negative current compensation value Iv_cmp_K, the inductance value Lpfc, the output voltage Vpfc, and the instantaneous input voltage Vin(t). The specific steps are as follows:

[0122] S901, calculate the second product of the inductance value Lpfc and the negative current compensation value, and calculate the second difference between the output voltage Vpfc and the instantaneous input voltage Vin(t);

[0123] Specifically, the second product = Lpfc × Iv_cmp_K; the second difference = Vpfc - Vin(t).

[0124] S902. The ratio of the second product to the second difference is used as the additional on-time Tr_cmp_new.

[0125] Specifically, additional conduction time

[0126] This application provides a control method for a PFC circuit. The method calculates a segmentation coefficient K based on a first current compensation value I_zcd, a preset second current compensation value I_offest, a preset delay time tzcd_set, an output voltage Vpfc, and the inductance value Lpfc of the inductor in the PFC circuit. It then calculates a negative current compensation value based on the segmentation coefficient K, the first current compensation value I_zcd, the preset second current compensation value I_offest, the preset delay time tzcd_set, the output voltage Vpfc, the instantaneous input voltage Vin(t), and the inductance value Lpfc of the inductor in the PFC circuit. Finally, it calculates an additional conduction time Tr_cmp_new based on the negative current compensation value, the inductance value Lpfc, the output voltage Vpfc, and the instantaneous input voltage Vin(t). The method controls the synchronous rectifier in the PFC circuit to conduct during the additional conduction time Tr_cmp_new, generating a negative current, thereby enabling the PFC circuit to achieve high-efficiency negative current compensation.

[0127] like Figure 10 The figure shows an embodiment of this application that uses an additional on-time Tr_cmp_new calculated based on the negative current compensation value to achieve high-efficiency negative current compensation in a PFC circuit. Specifically, under the condition of 176V input and 375V output, the figures from top to bottom represent the negative current Iv_fix_fac in the fixed negative current compensation control mode, the critical current Iv_min, and the negative current Iv_cmp_fzc_new in the PFC circuit controlled by the additional on-time Tr_cmp_new. Excessive negative current compensation leads to low efficiency and power loss. In contrast, the negative current Iv_cmp_fzc_new in this application is close to the critical current Iv_min, improving efficiency and reducing power loss.

[0128] like Figure 11 The figure shows another embodiment of this application, which uses an additional on-time Tr_cmp_new calculated based on the negative current compensation value to enable the PFC circuit to achieve high-efficiency negative current compensation. Under the condition of 275V input and 435V output, the figures from top to bottom represent the critical current Iv_min, the negative current Iv_fix_fac in the fixed negative current compensation control mode, and the negative current Iv_cmp_fzc_new generated by the PFC circuit during the additional on-time Tr_cmp_new. That is, in the fixed negative current compensation control mode, the main power supply in the PFC circuit is hard-turned on due to insufficient negative current compensation. However, the negative current Iv_cmp_fzc_new in this application is close to the critical current Iv_min, achieving ZVS and avoiding hard-turning of the main power supply.

[0129] Based on the same technical concept, the present application provides a control device for a PFC circuit. The principle of the control device for the PFC circuit is similar to that of the control method for the PFC circuit described above. Therefore, the implementation of the control device for the PFC circuit can refer to the implementation of the control method for the PFC circuit. Repeated parts will not be described again.

[0130] like Figure 12 The diagram shown is a structural schematic of a control device for a PFC circuit provided in an embodiment of this application, comprising:

[0131] The determination module 1201 is used to determine that the inductor current of the PFC circuit is 0;

[0132] The calculation module 1202 is used to calculate the negative current compensation value based on the instantaneous value of the input voltage and the magnitude of the voltage product. The voltage product is the product of the output voltage and the voltage segmentation coefficient. The voltage segmentation coefficient is calculated based on the first current compensation value, the preset second current compensation value, the preset delay time, the output voltage, and the inductance value of the inductor in the PFC circuit. The first current compensation value is calculated based on the absolute value of the difference between the negative current value at the zero-crossing point of the input voltage and the negative current value at the peak value of the input voltage under rated operating conditions without negative current compensation. The module also calculates the additional conduction time based on the negative current compensation value, the inductance value, the output voltage, and the instantaneous value of the input voltage.

[0133] The control module 1203 is used to control the synchronous rectifier in the PFC circuit to conduct for an additional conduction period and generate a negative current.

[0134] This application provides a control method, apparatus, and electronic device for a PFC circuit. The method includes: determining that the inductor current of the PFC circuit is 0; calculating a negative current compensation value based on the instantaneous value of the input voltage and the magnitude of the voltage product, wherein the voltage product is the product of the output voltage and the voltage segmentation coefficient, the voltage segmentation coefficient is calculated based on a first current compensation value, a preset second current compensation value, a preset delay time, the output voltage, and the inductance value of the inductor in the PFC circuit; the first current compensation value is calculated based on the absolute value of the difference between the negative current value at the zero-crossing point of the input voltage and the negative current value at the peak point of the input voltage under rated operating conditions without negative current compensation; calculating an additional conduction time based on the negative current compensation value, the inductance value, the output voltage, and the instantaneous value of the input voltage; and controlling the synchronous rectifier in the PFC circuit to conduct during the additional conduction time and generate a negative current. This application calculates the negative current compensation value based on the instantaneous value of the input voltage and the magnitude of the voltage product, and then calculates the additional conduction time of the PFC circuit. By controlling the additional conduction time of the synchronous rectifier in the PFC circuit, the PFC circuit can achieve high-efficiency negative current compensation.

[0135] In some embodiments, the calculation module 1202 is specifically used for:

[0136] If the instantaneous value of the input voltage is less than or equal to the voltage product, then the negative current compensation value is 0;

[0137] If the instantaneous value of the input voltage is greater than the voltage product, then the negative current compensation value is calculated based on the output voltage, the instantaneous value of the input voltage, the inductance value, the delay duration, the first current compensation value, and the second current compensation value.

[0138] In some embodiments, the calculation module 1202 is specifically used for:

[0139] Calculate the first difference between the instantaneous values ​​of the output voltage and the input voltage;

[0140] Calculate the first ratio between the first difference and the inductance value;

[0141] Calculate the first product of the first ratio and the delay duration;

[0142] Calculate the absolute value of the difference between the first product and the first current compensation value;

[0143] The difference between the absolute value and the second current compensation value is taken as the negative current compensation value.

[0144] In some embodiments, the calculation module 1202 is used for:

[0145] Calculate the second difference between the first current compensation value and the second current compensation value, and calculate the second product of the delay duration and the output voltage;

[0146] Calculate the second ratio of the second difference to the second product, and multiply the second ratio by the inductance value to obtain the third product;

[0147] The difference between 1 and the third product is used as the voltage segmentation coefficient.

[0148] In some embodiments, the calculation module 1202 is used to: calculate the first absolute value of the difference between the negative current value at the zero-crossing point of the input voltage and the negative current value at the peak point of the input voltage;

[0149] Calculate the third difference between the instantaneous values ​​of the output voltage and the input voltage, and the third ratio of the third difference to the inductance value;

[0150] Calculate the fourth product of the third ratio and the delay duration;

[0151] The sum of twice the first absolute value and the fourth product is taken as the first current compensation value.

[0152] In some embodiments, the calculation module 1202 is used for:

[0153] Calculate the second product of the inductance value and the negative current compensation value, and calculate the second difference between the instantaneous values ​​of the output voltage and the input voltage;

[0154] The ratio of the second product to the second difference is used as the additional conduction time.

[0155] After introducing a control method and apparatus for a PFC circuit according to an exemplary embodiment of this application, an electronic device according to another exemplary embodiment of this application will be described next.

[0156] like Figure 13 The diagram shown is a schematic of an electronic device provided in an embodiment of this application, including: a processor 1301; a memory 1302 for storing processor-executable instructions; wherein the processor 1301 implements the steps of any one of the methods of a PFC circuit control method by running the executable instructions.

[0157] This application provides a control method, apparatus, and electronic device for a PFC circuit. The method includes: determining that the inductor current of the PFC circuit is 0; calculating a negative current compensation value based on the instantaneous value of the input voltage and the magnitude of the voltage product, wherein the voltage product is the product of the output voltage and the voltage segmentation coefficient, the voltage segmentation coefficient is calculated based on a first current compensation value, a preset second current compensation value, a preset delay time, the output voltage, and the inductance value of the inductor in the PFC circuit; the first current compensation value is calculated based on the absolute value of the difference between the negative current value at the zero-crossing point of the input voltage and the negative current value at the peak point of the input voltage under rated operating conditions without negative current compensation; calculating an additional conduction time based on the negative current compensation value, the inductance value, the output voltage, and the instantaneous value of the input voltage; and controlling the synchronous rectifier in the PFC circuit to conduct during the additional conduction time and generate a negative current. This application calculates the negative current compensation value based on the instantaneous value of the input voltage and the magnitude of the voltage product, and then calculates the additional conduction time of the PFC circuit. By controlling the additional conduction time of the synchronous rectifier in the PFC circuit, the PFC circuit can achieve high-efficiency negative current compensation.

[0158] The present application has been described above with reference to block diagrams and / or flowcharts illustrating methods, apparatus (systems), and / or computer program products according to embodiments of the present application. It should be understood that a block of a block diagram and / or flowchart, as well as combinations of blocks of block diagrams and / or flowcharts, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, and / or other programmable data processing means to produce a machine, such that the instructions, executable via the computer processor and / or other programmable data processing means, create methods for implementing the functions / actions specified in the blocks of the block diagrams and / or flowcharts.

[0159] Accordingly, this application can also be implemented using hardware and / or software (including firmware, resident software, microcode, etc.). Furthermore, this application can take the form of a computer program product on a computer-usable or computer-readable storage medium, having computer-usable or computer-readable program code implemented in the medium for use by or in conjunction with an instruction execution system. In the context of this application, a computer-usable or computer-readable medium can be any medium that can contain, store, communicate, transmit, or deliver a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0160] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A control method for a PFC circuit, characterized in that, The method includes: The inductor current of the PFC circuit is determined to be 0. The negative current compensation value is calculated based on the instantaneous value of the input voltage and the magnitude of the voltage product. The voltage product is the product of the output voltage and the voltage segmentation coefficient. The voltage segmentation coefficient is calculated based on the first current compensation value, the preset second current compensation value, the preset delay time, the output voltage, and the inductance value of the inductor in the PFC circuit. The first current compensation value is calculated based on the absolute value of the difference between the negative current value at the zero-crossing point of the input voltage and the negative current value at the peak point of the input voltage under rated operating conditions without negative current compensation. The additional conduction time is calculated based on the negative current compensation value, the inductance value, the output voltage, and the instantaneous input voltage value. The synchronous rectifier in the PFC circuit is controlled to conduct during the additional conduction period and generate a negative current.

2. The method as described in claim 1, characterized in that, The calculation of the negative current compensation value based on the instantaneous value of the input voltage and the product of the voltages includes: If the instantaneous value of the input voltage is less than or equal to the voltage product, then the negative current compensation value is 0; If the instantaneous value of the input voltage is greater than the voltage product, then the negative current compensation value is calculated based on the output voltage, the instantaneous value of the input voltage, the inductance value, the delay duration, the first current compensation value, and the second current compensation value.

3. The method as described in claim 2, characterized in that, The step of calculating the negative current compensation value based on the output voltage, the instantaneous value of the input voltage, the inductance value, the delay duration, the first current compensation value, and the second current compensation value includes: Calculate the first difference between the instantaneous values ​​of the output voltage and the input voltage; Calculate the first ratio between the first difference and the inductance value; Calculate the first product of the first ratio and the delay duration; Calculate the second absolute value of the difference between the first product and the first current compensation value; The difference between the second absolute value and the second current compensation value is taken as the negative current compensation value.

4. The method as described in claim 1, characterized in that, The voltage segmentation coefficient is calculated in the following manner: Calculate the second difference between the first current compensation value and the second current compensation value, and calculate the second product of the delay duration and the output voltage; Calculate the second ratio of the second difference to the second product, and multiply the second ratio by the inductance value to obtain the third product; The difference between 1 and the third product is used as the voltage segmentation coefficient.

5. The method as described in claim 1, characterized in that, The first current compensation value is calculated in the following manner: Calculate the first absolute value of the difference between the negative current value at the zero-crossing point of the input voltage and the negative current value at the peak point of the input voltage; Calculate the third difference between the instantaneous values ​​of the output voltage and the input voltage, and the third ratio of the third difference to the inductance value; Calculate the fourth product of the third ratio and the delay duration; The sum of twice the first absolute value and the fourth product is taken as the first current compensation value.

6. The method according to any one of claims 1 to 5, characterized in that, The calculation of the additional conduction time based on the negative current compensation value, the inductance value, the output voltage, and the instantaneous input voltage value includes: Calculate the second product of the inductance value and the negative current compensation value, and calculate the second difference between the instantaneous values ​​of the output voltage and the input voltage; The ratio of the second product to the second difference is used as the additional conduction time.

7. An electronic device, characterized in that, include: processor; A memory for storing processor-executable instructions; wherein the processor implements the steps of the method according to any one of claims 1 to 6 by executing the executable instructions.

8. A control device for a PFC circuit, characterized in that, The device includes: A determination module is used to determine that the inductor current of the PFC circuit is 0; The calculation module is used to calculate the negative current compensation value based on the instantaneous value of the input voltage and the magnitude of the voltage product. The voltage product is the product of the output voltage and a voltage segmentation coefficient, which is calculated based on a first current compensation value, a preset second current compensation value, a preset delay time, the output voltage, and the inductance value of the inductor in the PFC circuit. The first current compensation value is calculated based on the absolute value of the difference between the negative current value at the zero-crossing point of the input voltage and the negative current value at the peak value of the input voltage under rated operating conditions without negative current compensation. The module also calculates an additional conduction time based on the negative current compensation value, the inductance value, the output voltage, and the instantaneous value of the input voltage. The control module is used to control the synchronous rectifier in the PFC circuit to conduct during the additional conduction period and generate a negative current.

9. The apparatus as claimed in claim 8, characterized in that, The calculation module is specifically used for: If the instantaneous value of the input voltage is less than or equal to the voltage product, then the negative current compensation value is 0; If the instantaneous value of the input voltage is greater than the voltage product, then the negative current compensation value is calculated based on the output voltage, the instantaneous value of the input voltage, the inductance value, the delay duration, the first current compensation value, and the second current compensation value.

10. The apparatus as claimed in claim 9, characterized in that, The calculation module is specifically used for: Calculate the first difference between the instantaneous values ​​of the output voltage and the input voltage; Calculate the first ratio between the first difference and the inductance value; Calculate the first product of the first ratio and the delay duration; Calculate the absolute value of the difference between the first product and the first current compensation value; The difference between the absolute value and the second current compensation value is taken as the negative current compensation value.

11. The apparatus as claimed in claim 8, characterized in that, The calculation module is specifically used for: Calculate the second difference between the first current compensation value and the second current compensation value, and calculate the second product of the delay duration and the output voltage; Calculate the second ratio of the second difference to the second product, and multiply the second ratio by the inductance value to obtain the third product; The difference between 1 and the third product is used as the voltage segmentation coefficient.

12. The apparatus as claimed in claim 8, characterized in that, The calculation module is specifically used for: Calculate the first absolute value of the difference between the negative current value at the zero-crossing point of the input voltage and the negative current value at the peak point of the input voltage; Calculate the third difference between the instantaneous values ​​of the output voltage and the input voltage, and the third ratio of the third difference to the inductance value; Calculate the fourth product of the third ratio and the delay duration; The sum of twice the first absolute value and the fourth product is taken as the first current compensation value.

13. The apparatus according to any one of claims 8 to 12, characterized in that, The calculation module is specifically used for: Calculate the second product of the inductance value and the negative current compensation value, and calculate the second difference between the instantaneous values ​​of the output voltage and the input voltage; The ratio of the second product to the second difference is used as the additional conduction time.

Images