Power factor correction control circuit, method, apparatus and household appliance

Abstract

Disclosed in the present application are a power factor correction control circuit, a method, an apparatus and a household appliance. The circuit comprises an alternating current input end, a rectifier module and a direct current output end which are successively connected. A sampling resistor and a sampling control module connected in parallel are provided between the rectifier module and a negative electrode end of the direct current output end; the end of the sampling resistor close to the direct current output end is grounded, and, by means of a switch transistor, is connected to the alternating current input end; an inductor unit is provided between the alternating current input end and the switch transistor, and a signal output end of the sampling control unit is connected to a control pin of the switch transistor; the sampling control module is used for acquiring a sampling current of the sampling resistor, and sending a driving signal corresponding to the sampling current to the switch transistor so as to control on-off of the switch transistor, such that the inductor unit discharges to a positive electrode end of the direct current output end.

Description

Control circuit, method, device and household appliance for power factor correction

[0001] Cross-reference to related applications

[0002] The present application claims priority to the Chinese patent application No. 202410866224.4, filed on June 28, 2024, and entitled “Control circuit, method, device and household appliance for power factor correction”, the whole content of the above patent application is incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to the technical field of electronic circuits, in particular to a control circuit, method, device and household appliance for power factor correction. BACKGROUND

[0004] In the modern field of power electronics, power factor correction (PFC) technology is a key technology to improve the efficiency of power conversion and the quality of electric energy. It adjusts the phase relationship between input current and voltage to reduce reactive power and improve power factor. Traditional multi-pulse or single-pulse PFC control methods involve current sampling and switch on-off control. Current sampling detects the size and phase of the current, and switch on-off control adjusts the switch state according to the sampling results.

[0005] However, in existing designs, current sampling and switch on-off control need to use current transformers or Hall sensors and other modules. These modules need to be sampled at the current input end and controlled at the output end. The circuit complexity is high, the design and manufacturing difficulty is great, and in order to make the circuit easy to implement, the current sampling module and the switch on-off control module usually need to be designed to be electrically isolated from each other. However, the design of electrical isolation not only increases the cost, but also limits the integration of the circuit, which is not conducive to the miniaturization design of the circuit. SUMMARY

[0006] The present application aims to at least solve one of the technical problems existing in the prior art, and provides a control circuit, method, device and household appliance for power factor correction, which can simplify the circuit based on sampling resistance sampling, so that circuit sampling and on-off control occur at the output end, and then the sampling control module can have the functions of sampling and control at the same time, without the need for electrical isolation of the corresponding functional components, so as to reduce the cost and improve the integration of the circuit.

[0007] In a first aspect, embodiments of the present application provide a power factor correction control circuit, comprising: an AC input end, a rectifier module and a DC output end connected in sequence, wherein: a sampling resistor and a sampling control module are connected in parallel between the rectifier module and a negative terminal of the DC output end, one end of the sampling resistor is grounded and connected to the AC input end through a switch tube, an inductor unit is arranged between the AC input end and the switch tube, and a signal output end of the sampling control unit is connected to a control pin of the switch tube; the sampling control module is configured to obtain a sampling current of the sampling resistor and send a driving signal corresponding to the sampling current to the switch tube to control on-off of the switch tube, so that the inductor unit discharges to a positive terminal of the DC output end.

[0008] The power factor correction control circuit provided by the embodiments of the present application has at least the following beneficial effects: the power factor correction control circuit comprises an AC input end, a rectifier module and a DC output end. A sampling resistor and a sampling control module are connected in parallel between the rectifier module and a negative terminal of the DC output end. One end of the sampling resistor is grounded and connected to the AC input end through a switch tube. An inductor unit is arranged between the AC input end and the switch tube. A signal output end of the sampling control module is connected to a control pin of the switch tube. The sampling control module obtains a current of the sampling resistor and sends a driving signal to the switch tube to control on-off of the switch tube, so that the inductor unit discharges to a positive terminal of the DC output end. In the present application, the sampling resistor is arranged in parallel between the rectifier module and the negative terminal of the DC output end, so that the sampling resistor is directly integrated near the DC output end instead of the input end. The sampling control module can be connected in parallel with the sampling resistor, and its signal output end is directly connected to the control pin of the switch tube, so that the sampling control module can obtain current information on the sampling resistor in real time and directly control on-off state of the switch tube. One end of the sampling resistor near the DC output end is grounded and connected to the AC input end through the switch tube. On-off of the switch tube is controlled by the sampling control module according to current information on the sampling resistor. It can be understood that, since the sampling resistor and the sampling control module are arranged near the DC output end, the sampling control module has both sampling and control functions, can include a sampling unit for sampling and a driving unit for driving, to realize that sampling and control share the same ground network, that is, realize non-isolated combination, so that complex wiring and electrical isolation from the input end to the output end are not needed, no additional isolation elements are needed, the integration of the circuit is improved, the miniaturization design of the circuit is facilitated, and the overall cost is reduced.

[0009] In some embodiments, the sampling control module comprises a sampling unit and a driving unit, a first voltage terminal of the sampling unit and the driving unit is connected to one end of the sampling resistor close to the rectifier module, a second voltage terminal of the sampling unit and the driving unit is connected to one end of the sampling resistor close to the DC output terminal, the sampling unit is configured to obtain a voltage signal of the sampling resistor and obtain a sampling current according to the voltage signal; a first signal output terminal of the driving unit is connected to a control pin of the switch tube, and the driving unit is configured to send the driving signal based on a control signal corresponding to the sampling current received.

[0010] In some embodiments, the control circuit further comprises a control unit connected to the sampling unit and the driving unit respectively, the control unit is configured to obtain the sampling current and send the control signal to the driving unit based on the voltage signal.

[0011] In some embodiments, the input timing of the control signal received by the driving unit is the same as the output timing of the driving signal sent by the driving unit, when the control signal is a high-level signal, the driving signal is a high-level signal, and the switch tube is turned on; when the control signal is a low-level signal, the driving signal is a low-level signal, and the switch tube is turned off.

[0012] In some embodiments, a second signal output terminal of the driving unit is connected to the control unit, and the driving unit is further configured to obtain the voltage signal of the sampling resistor, and send an overcurrent signal to the control unit through the second signal output terminal when the voltage signal is greater than or equal to a preset voltage threshold, so that the control unit performs overcurrent fault processing.

[0013] In some embodiments, one end of the switch tube close to the AC input terminal is connected to a live terminal of the AC input terminal through a first diode and connected to a neutral terminal of the AC input terminal through a second diode, and the negative terminals of the first diode and the second diode are close to the switch tube.

[0014] In some embodiments, the inductor unit is arranged between the live terminal and the first diode; or, the inductor unit is arranged between the neutral terminal and the second diode.

[0015] In some embodiments, the sampling resistor comprises a non-inductive resistor.

[0016] In some embodiments, the switch tube comprises an insulated gate bipolar transistor.

[0017] In a second aspect, the embodiments of the present application provide a control method of a power factor correction circuit, which is applied to a sampling control module in a control circuit for power factor correction, the control circuit comprising an alternating current (AC) input end, a rectification module and a direct current (DC) output end connected in sequence, wherein a sampling resistor and the sampling control module are connected in parallel between the rectification module and a negative terminal of the DC output end, one end of the sampling resistor close to the DC output end is grounded and the sampling resistor is connected to the AC input end through a switch tube, an inductor unit is arranged between the AC input end and the switch tube, and a signal output end of the sampling control unit is connected to a control pin of the switch tube; the method comprises: obtaining a sampling current of the sampling resistor and sending a driving signal corresponding to the sampling current to the switch tube to control on-off of the switch tube, so that the inductor unit discharges to a positive terminal of the DC output end.

[0018] The control method of the power factor correction circuit provided by the embodiments of the present application has at least the following beneficial effects: the method of the present application integrates the sampling resistor close to the DC output end by connecting the sampling resistor in parallel between the rectification module and the negative terminal of the DC output end; the sampling control module is connected in parallel with the sampling resistor, and the signal output end of the sampling control module is directly connected to the control pin of the switch tube, so that current information can be obtained in real time and the switch tube can be controlled to turn on and off; one end of the sampling resistor is grounded, and the sampling resistor is connected to the AC input end through the switch tube, the on-off of the switch tube is controlled by the sampling control module according to the current information, the sampling resistor and the sampling control module are arranged close to the DC output end, the sampling control module has the functions of sampling and control, and includes a sampling unit and a driving unit, so that the non-isolated combination of the sampling unit and the driving unit is realized, the circuit integration is improved, the miniaturization design is facilitated, the separate current transformer or Hall sensor is saved, the additional modules and wiring are reduced, and the cost is reduced.

[0019] In a third aspect, the embodiments of the present application provide a control device for power factor correction, comprising the control circuit for power factor correction according to any one of the embodiments of the first aspect.

[0020] The power factor correction control device provided by the embodiments of the present application has at least the following beneficial effects: the sampling resistor is integrated near the DC output end by connecting the sampling resistor in parallel with the negative terminal of the rectifier module and the DC output end; the sampling control module is connected in parallel with the sampling resistor, and the signal output end of the sampling control module is directly connected with the control pin of the switch tube, so that the current information can be obtained in real time and the switch tube can be controlled to turn on and off; one end of the sampling resistor is connected with the ground through the switch tube, and the AC input end is connected through the switch tube, and the on-off is controlled by the sampling control module according to the current information; the sampling resistor and the sampling control module are both arranged near the DC output end, the sampling control module has the functions of sampling and control, and includes a sampling unit and a driving unit, so that the non-isolated combination of the sampling unit and the driving unit is realized, the circuit integration is improved, the miniaturization design is facilitated, the separate current transformer or Hall sensor is saved, the additional module and wiring are reduced, and the cost is reduced.

[0021] In a fourth aspect, the embodiments of the present application provide a household appliance comprising the power factor correction control device according to any one of the embodiments of the third aspect.

[0022] The household appliance provided by the embodiments of the present application has at least the following beneficial effects: the sampling resistor is integrated near the DC output end by connecting the sampling resistor in parallel with the negative terminal of the rectifier module and the DC output end; the sampling control module is connected in parallel with the sampling resistor, and the signal output end of the sampling control module is directly connected with the control pin of the switch tube, so that the current information can be obtained in real time and the switch tube can be controlled to turn on and off; one end of the sampling resistor is connected with the ground through the switch tube, and the AC input end is connected through the switch tube, and the on-off is controlled by the sampling control module according to the current information; the sampling resistor and the sampling control module are both arranged near the DC output end, the sampling control module has the functions of sampling and control, and includes a sampling unit and a driving unit, so that the non-isolated combination of the sampling unit and the driving unit is realized, the circuit integration is improved, the miniaturization design is facilitated, the separate current transformer or Hall sensor is saved, the additional module and wiring are reduced, and the cost is reduced.

[0023] Other features and advantages of the present application will be set forth in the descriptions below, and in part will become apparent to those skilled in the art upon examination of the following or can be learned by practice of the present application. The objects and other advantages of the present application can be realized and attained by the structure particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0024] The accompanying drawings are included to provide a further understanding of the technical solutions of the present application, and constitute a part of the specification, and are used to explain the technical solutions of the present application together with the embodiments of the present application, and do not constitute a limitation on the technical solutions of the present application.

[0025] The present application will be further described below with reference to the accompanying drawings and embodiments.

[0026] Figure 1 is a circuit diagram of a control circuit for power factor correction according to an embodiment of the present application;

[0027] Figure 2 is a current flow diagram of a control circuit for power factor correction according to an embodiment of the present application;

[0028] Figure 3 is another current flow diagram of a control circuit for power factor correction according to an embodiment of the present application;

[0029] Figure 4 is another current flow diagram of a control circuit for power factor correction according to an embodiment of the present application;

[0030] Figure 5 is another current flow diagram of a control circuit for power factor correction according to an embodiment of the present application;

[0031] Figure 6 is a flow diagram of a control method for a power factor correction circuit according to an embodiment of the present application. DETAILED DESCRIPTION

[0032] This part will describe the specific embodiments of the present application in detail, the preferred embodiments of the present application are shown in the accompanying drawings, the role of the drawings is to supplement the description of the text part with figures, so that people can intuitively and visually understand each technical feature and the overall technical solution of the present application, but it cannot be understood as a limitation on the protection scope of the present application.

[0033] In the description of the embodiments of the present application, several meanings are one or more, the meaning of multiple is two or more, greater than, less than, more than, etc. are understood as not including the number, above, below, within, etc. are understood as including the number, "at least one" means one or more, "at least one of the following" and similar expressions mean any combination of these items, including any combination of single or multiple items. If there is a description of "first", "second", etc. is only used to distinguish technical features for the purpose, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the sequence of indicated technical features.

[0034] It should be noted that the terms such as setting, installing, connecting, etc. in the embodiments of the present application should be understood broadly, and those skilled in the art can determine the specific meaning of the above terms in the embodiments of the present application in combination with the specific content of the technical solution. For example, the term "connection" can be mechanical connection, electrical connection or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium.

[0035] In the field of modern power electronics, power factor correction (PFC) technology is one of the key technologies to improve the efficiency of power conversion and power quality. PFC technology adjusts the phase relationship between input current and input voltage to make the current as in-phase as possible with the voltage, thereby reducing reactive power and improving power factor. Existing PFC control methods are mainly divided into multi-pulse and single-pulse methods. These methods usually require two key steps: current sampling and switch on-off control. Current sampling is used to monitor the size and phase of the input current, while switch on-off control adjusts the switching state of the power conversion device according to the sampling results to achieve power factor correction.

[0036] However, there are some significant problems in the design of existing current sampling and switch on-off control circuits. First, to achieve accurate current sampling, current transformers or Hall sensors and other circuit modules are usually used. These modules need to be sampled at the current input end and controlled at the output end. This design not only increases the complexity of the circuit, but also often leads to a decrease in system stability and reliability due to the need for precise control. In addition, to improve the safety and anti-interference ability of the system, the current sampling module and the switch on-off control module usually need to be designed to be electrically isolated from each other, resulting in the current sampling module and the switch on-off control module not being able to share the ground, thereby increasing the difficulty of design and manufacturing. The design of electrical isolation not only increases the cost, but also limits the integration of the circuit, making the entire system more bulky and complex.

[0037] In some application scenarios, such as household appliances and industrial control devices, users have strict requirements for the size, cost and energy efficiency of the devices. Therefore, while existing PFC control circuits achieve high efficiency of power conversion, they also need to consider cost control and circuit integration issues. However, the design of electrical isolation not only increases the cost, but also limits the integration of the circuit, which is not conducive to the miniaturization of the circuit.

[0038] Based on this, the embodiment of the present application discloses a power factor correction control circuit, method, device and household appliance, the circuit comprises: AC input end, rectifier module and DC output end connected in turn, wherein: the rectifier module and the negative terminal of the DC output end are provided with parallel sampling resistor and sampling control module, the one end of the sampling resistor close to the DC output end is grounded and connected with the AC input end through the switch tube, the inductor unit is arranged between the AC input end and the switch tube, and the signal output end of the sampling control unit is connected with the control pin of the switch tube; the sampling control module is used for acquiring the sampling current of the sampling resistor, and sending the driving signal corresponding to the sampling current to the switch tube, so as to control the on-off of the switch tube, so that the inductor unit discharges to the positive terminal of the DC output end, the circuit can be simplified based on the sampling of the sampling resistor, so that the circuit sampling and on-off control occur in the output end, and then the sampling control module can have the functions of sampling and control at the same time, without electrically isolating the corresponding functional components, so as to reduce the cost and improve the circuit integration degree.

[0039] The embodiment of the present application is further described below in combination with the drawings.

[0040] Referring to FIG. 1, FIG. 1 is a circuit diagram of the power factor correction control circuit provided by the embodiment of the present application, in the first aspect, the embodiment of the present application provides a power factor correction control circuit, comprising: AC input end, rectifier module BR1 and DC output end connected in turn, wherein: the rectifier module BR1 and the negative terminal of the DC output end are provided with parallel sampling resistor R316 and sampling control module, the one end of the sampling resistor R316 close to the DC output end is grounded and connected with the AC input end through the switch tube Q4, the inductor unit L601 is arranged between the AC input end and the switch tube Q4, and the signal output end of the sampling control unit is connected with the control pin of the switch tube Q4; the sampling control module is used for acquiring the sampling current of the sampling resistor R316, and sending the driving signal corresponding to the sampling current to the switch tube Q4, so as to control the on-off of the switch tube Q4, so that the inductor unit L601 discharges to the positive terminal of the DC output end.

[0041] Wherein, the AC input end is the starting point of the power factor correction control circuit, which receives external AC power input; the rectifier module BR1 is located behind the AC input end, which converts AC into pulsating DC. The rectifier module BR1 usually contains diodes or other rectifier elements; the boost module is located behind the rectifier module BR1, which aims to improve the voltage of the DC to meet the needs of specific applications, corresponding to FIG. 1, the AC input end corresponds to the neutral line end N and the live line end L of the AC power supply AC, the rectifier module BR1 corresponds to the four diodes in the figure, and the DC output end corresponds to the two ends of the electrolytic capacitor E3 in FIG. 1, which is used to provide load driving voltage for the load connected behind.

[0042] In some embodiments, the embodiments of the present application provide a power factor correction control circuit, comprising: an AC input end, a rectifier module BR1, a DC output end. The rectifier module BR1 is provided with a sampling resistor R316 and a sampling control module in parallel between the rectifier module BR1 and the negative pole end of the DC output end; one end of the sampling resistor R316 is grounded and connected with the AC input end through a switch tube Q4. An inductor unit L601 is provided between the AC input end and the switch tube Q4; the output end of the sampling control module is connected with the control pin of the switch tube Q4. The sampling control module obtains the current of the sampling resistor R316 and sends a driving signal to the switch tube Q4 to control the on-off of the switch tube Q4, so that the inductor unit L601 discharges to the positive pole end of the DC output end, wherein, the present application sets the sampling resistor R316 in parallel between the rectifier module BR1 and the negative pole end of the DC output end, so that the sampling resistor R316 is directly integrated near the DC output end instead of the input end, the sampling control module can be connected in parallel with the sampling resistor R316, and the signal output end thereof is directly connected with the control pin of the switch tube Q4, so that the sampling control module can obtain the current information on the sampling resistor R316 in real time and directly control the on-off state of the switch tube Q4, one end of the sampling resistor R316 close to the DC output end is grounded and connected with the AC input end through the switch tube Q4, and the on-off of the switch tube Q4 is controlled by the sampling control module according to the current information on the sampling resistor R316.

[0043] It can be understood that, since the sampling resistor R316 and the sampling control module are both arranged near the DC output end, the sampling control module has the functions of sampling and control, can include a sampling unit for sampling and a driving unit for driving, so as to realize that the sampling and the control share the same ground network, that is, realize non-isolated combination, save the complex wiring and the electrical isolation requirement from the input end to the output end, do not need additional isolation elements, improve the integration of the circuit, and are beneficial to the miniaturization design of the circuit; and since the separate current transformer or the Hall sensor for current sampling is no longer needed and the electrical isolation requirement is saved, the additional modules and wiring can be effectively reduced, so as to reduce the overall cost.

[0044] In some embodiments, an inductor unit L601 is arranged between the AC input and the switch tube Q4. The inductor generates a voltage drop when the current changes, and the voltage drop is proportional to the rate of change of the current. By arranging the inductor on the AC side, the voltage drop that the switch tube Q4 needs to overcome when performing switching operations is smaller. Because the inductance has a small impedance to AC, this can reduce the loss of the switch tube Q4 during switching and improve efficiency. Arranging the inductor on the AC side can also help to suppress high-frequency electromagnetic interference. Because the inductor has a high impedance to high-frequency signals, it can filter out high-frequency noise generated by switching operations and reduce electromagnetic interference. In addition, the circuit of the present application can be applied to both multi-pulse PFC control circuits and single-pulse PFC control circuits, so that the PFC drive control can be implemented using a non-isolated scheme. This eliminates the need for electrical isolation of the corresponding functional components for sampling and driving, thereby reducing costs and improving circuit integration. Regardless of whether it is a multi-pulse PFC or a single-pulse PFC, arranging the inductor on the AC side can bring the above advantages.

[0045] In some embodiments, the sampling control module includes a sampling unit and a driving unit. The sampling unit includes the current sampling circuit in FIG. 1, and the driving unit includes the drive control circuit in FIG. 1. The first voltage end of the sampling unit and the driving unit is connected to one end of the sampling resistor R316 close to the rectifier module BR1, and the second voltage end of the sampling unit and the driving unit is connected to one end of the sampling resistor R316 close to the DC output end. The sampling unit is used to obtain a voltage signal of the sampling resistor R316 and obtain a sampling current according to the voltage signal. The first signal output end of the driving unit is connected to the control pin of the switch tube Q4. The driving unit is used to send a driving signal based on the control signal corresponding to the received sampling current, so as to realize that sampling and control share the same ground network and realize non-isolated combination.

[0046] It can be understood that in the circuit design, "ground" refers to the reference point of the circuit, and all voltages are measured relative to this reference point. Sharing the same ground network means that the sampling unit and the control unit are connected to the same reference point, which can simplify the wiring of the circuit, reduce noise and interference in the ground loop, and improve safety and anti-interference ability. In the traditional scheme, the current sampling and driving circuit and the control unit may be designed to be electrically isolated, i.e. they are not directly electrically connected. This is usually achieved by using isolation elements such as optocouplers or transformers. The non-isolated combination in the present application directly connects the sampling unit and the driving unit and the control unit electrically without using additional isolation elements. In this design, the sampling unit is responsible for detecting the current through the sampling resistor R316 and converting it into a voltage signal, which is directly transmitted to the control unit without passing through an isolation layer. After receiving the voltage signal of the sampling current, the control unit controls the on-off of the switch tube Q4 through the driving unit based on the signal to achieve control of the circuit. This can effectively reduce costs, reduce circuit complexity, and improve response speed.

[0047] In some embodiments, the control circuit further comprises a control unit connected with the sampling unit and the driving unit respectively, the control unit is used for acquiring the sampling current, and sending a control signal to the driving unit based on the voltage signal. Referring to FIG. 1, the current sampling circuit can send the sampling current to the control unit through the port of PFC_I, and the control unit can send the control signal to the driving control circuit based on the voltage signal through the port of PFC_C. The driving control circuit is also connected with a 15V power supply. It can be understood that the functional components corresponding to the sampling and control circuit in the present application can use highly integrated chips, thereby realizing weak power non-isolated power supply, which is conducive to the miniaturization design of the switching transformer.

[0048] Referring to FIG. 2 to FIG. 5, FIG. 2 and FIG. 5 are current flow direction diagrams of the power factor correction control circuit provided by the embodiments of the present application. The rectifier module BR1 includes a bridge stack of four diodes, corresponding to the discharge of the inductor unit L601 to the positive terminal of the DC output end, and the current flow direction when the circuit completes the boost function. In some embodiments, when the AC input voltage is the positive half-axis, the inductor unit L601 stores energy when the switch tube Q4 is turned on. The current flows through the inductor unit L601, the first diode D3, the switch tube Q4, the sampling resistor R316, and one of the diodes of the rectifier module BR1. The current flow direction diagram is shown in FIG. 2. In some embodiments, when the switch tube Q4 is turned off, the inductor unit L601 transmits energy to the electrolytic capacitor E3. The current flows through the inductor unit L601, the rectifier module BR1, the electrolytic capacitor E3, the sampling resistor R316, and the rectifier module BR1. The current flow direction diagram is shown in FIG. 3. In some embodiments, when the AC input voltage is the negative half-axis, the inductor unit L601 stores energy when the switch tube Q4 is turned on. The current flows through the inductor unit L601, the second diode D4, the switch tube Q4, the sampling resistor R316, one of the diodes of the rectifier module BR1, and the inductor unit L601. The current flow direction diagram is shown in FIG. 4. In some embodiments, when the switch tube Q4 is turned off, the inductor unit L601 transmits energy to the electrolytic capacitor E3. The current flows through the rectifier module BR1, the electrolytic capacitor E3, the sampling resistor R316, the rectifier module BR1, and the inductor unit L601. The current flow direction diagram is shown in FIG. 5. The mains rectification is half-wave, then filtered by the bus capacitor, and becomes DC voltage.

[0049] In some embodiments, the input timing of the driving unit receiving the control signal is the same as the output timing of the driving unit sending the driving signal, when the control signal is a high-level signal, the driving signal is a high-level signal, and the switch tube Q4 is turned on; when the control signal is a low-level signal, the driving signal is a low-level signal, and the switch tube Q4 is turned off; specifically, the sampling unit realizes current sampling through the non-inductive resistor, and the non-inductive resistor converts the current flowing therethrough into a voltage signal, because the current flowing through the resistor will generate a voltage drop proportional to the current (according to Ohm's law, V=I*R), the collected voltage signal (PFC_I) is an analog voltage which simulates the actual current size, the analog voltage signal PFC_I is transmitted to the control unit, the control unit obtains the PFC current information, and performs real-time closed-loop control on the PFC according to the information, so as to maintain the current in the expected range; relatively, the driving unit can use an integrated driving chip to control the conduction and cutoff of the power switch device, the driving unit has one-way input and one-way output functions, and the input and output timing is the same, which makes the output state of the driving chip synchronized with the input state, when PFC_C inputs a high level, the driving chip outputs a high level, resulting in the conduction of IGBT, when PFC_C inputs a low level, the driving chip outputs a low level, resulting in the cutoff of IGBT, so as to realize the corresponding sampling and control steps of power factor correction.

[0050] In some embodiments, the second signal output end of the driving unit is connected with the control unit, and the driving unit is further used for acquiring a voltage signal of the sampling resistor R316, and when the voltage signal is greater than or equal to a preset voltage threshold, an overcurrent signal is sent to the control unit through the second signal output end, so that the control unit performs overcurrent fault processing; specifically, the driving unit also has an overcurrent detection function, which realizes this function by detecting the voltage across the non-inductive resistor, if the detected voltage value reaches the preset threshold, it indicates that there is an overcurrent in the circuit, once the overcurrent is detected, the output of the driving chip will be locked, so that the PFC works invalidly, so as to protect the circuit from being damaged, at the same time, the overcurrent fault is fed back to the MCU through the second signal output end PFC_FO port, the system will report the overcurrent protection fault, so that corresponding protection measures are taken, thereby improving the stability and reliability of the system.

[0051] In some embodiments, the switch tube Q4 is connected with the live wire end of the alternating current input end through the first diode D3 and connected with the zero line end of the alternating current input end through the second diode D4, and the negative ends of the first diode D3 and the second diode D4 are close to the switch tube Q4, wherein the first diode and the second diode are used as rectifier devices, which allow current to flow only in one direction, ensuring the correct direction of the current.

[0052] In some embodiments, the inductor unit L601 is arranged between the live wire end and the first diode D3; or, the inductor unit L601 is arranged between the zero wire end and the second diode D4, so that the inductor unit stores energy during the conduction of the switch tube and releases energy when the switch tube is cut off.

[0053] In some embodiments, the sampling resistor R316 includes a non-inductive resistor, which can more truly reflect the current size compared to ordinary resistors. The larger the current, the larger the load size. Therefore, by sampling the multi-pulse PFC current through the non-inductive resistor as control, the traditional Hall sensor or current transformer can be replaced. The advantages are low cost and simple control. It can be understood that the previous multi-pulse PFC control circuit uses a current transformer or a Hall sensor to collect the input current, which has a high circuit cost and a complex circuit design. Meanwhile, the driving control also uses an isolation scheme, which also has a high cost and is not conducive to circuit miniaturization design. Therefore, the present application uses a non-inductive resistor to collect the input current. Due to its characteristics, the non-inductive resistor can more truly reflect the current size through it and is not affected by current surges. This makes it very suitable for current sampling. Compared to the Hall sensor or current transformer, the non-inductive resistor has a lower cost, which helps to reduce the overall circuit cost. Using a non-inductive resistor for current sampling simplifies the design of the control circuit because there is no need for complex signal processing circuit to analyze the sensor signal.

[0054] The non-inductive resistor is a specially designed resistor with the main feature of having very low self-induction characteristics. In power electronics and switching power supply design, self-induction effect is usually a factor that needs to be avoided because it can cause a large voltage spike when the current changes suddenly, which can damage sensitive components in the circuit or cause electromagnetic interference (EMI). The design of the non-inductive resistor is to minimize this self-induction effect, with low self-induction, no significant voltage spike when the current changes rapidly, fast response, high stability, and low noise, etc. Therefore, in the power factor correction (PFC) circuit application, the non-inductive resistor can be used for accurate current sampling to achieve accurate current control. The non-inductive resistor can include a metal film resistor, a thick film resistor, and a wire-wound resistor.

[0055] It can be understood that, compared to the existing isolated current sampling scheme, since one end of the non-inductive resistor is grounded, the circuit layout is simplified, forming a ground loop, so that the over-current protection corresponding components and the driving control corresponding components connected in parallel on both sides of the sampling resistor R316 can be integrated in one chip, further simplifying the circuit design, reducing external components, improving reliability, and facilitating circuit miniaturization design.

[0056] In some embodiments, the switch tube Q4 can include IGBT (Insulated Gate Bipolar Transistor), MOSFET (Metal Oxide Semiconductor Field Effect Transistor), SiC (Silicon Carbide), GaN (Gallium Nitride) devices, and FRD (Fast Recovery Diode) such as SiFRD and SiCFRD, etc., wherein the insulated gate bipolar transistor combines the advantages of MOSFET and bipolar transistor (BJT), with high input impedance and low on-state voltage drop characteristics; the metal oxide semiconductor field effect transistor is widely used in switching power supply and signal processing due to its high switching speed, low on-state resistance and simple driving requirement; the silicon carbide device has the characteristics of good high temperature stability, high thermal conductivity and high breakdown voltage, and is suitable for high temperature, high efficiency and high frequency application scenarios; the gallium nitride device is concerned due to its high electron mobility, low on-state resistance and high switching frequency, and is suitable for high efficiency, small size power converter and radio frequency application; the silicon-based fast recovery diode has fast switching capability and lower forward voltage drop, and is suitable for scenes requiring fast recovery time; the silicon carbide-based fast recovery diode provides higher operating temperature, lower on-state loss and faster switching speed, and is suitable for more demanding environments and high efficiency requirements. The above switch tube Q4 can be used to switch the on-off state to make the energy storage element in the first branch or the second branch discharge to the DC output end, thereby providing a wider range of voltage output to meet the voltage requirements of different loads.

[0057] In summary, the control circuit of the power factor correction of the present application can use the non-inductive resistance to collect the input current, instead of the traditional Hall sensor or current transformer, the topology control is simple and the cost is low, and the PFC driving control can meet the non-isolation scheme, the circuit can be simplified based on the sampling of the sampling resistance R316, so that the circuit sampling and on-off control occur at the output end, and the sampling control module can simultaneously have the functions of sampling and control, without the need for electrical isolation of the corresponding functional components, thereby reducing the cost and improving the circuit integration level.

[0058] Referring to FIG. 6, FIG. 6 is a step diagram of a control method of a power factor correction circuit according to an embodiment of the present application. In a second aspect, the embodiment of the present application provides a control method of a power factor correction circuit. The method is applied to a sampling control module in a control circuit of a power factor correction. The control circuit includes an AC input end, a rectifier module and a DC output end connected in sequence. A sampling resistance and a sampling control module are connected in parallel between the rectifier module and the negative terminal of the DC output end. One end of the sampling resistance close to the DC output end is grounded and connected to the AC input end through a switch tube. An inductor unit is arranged between the AC input end and the switch tube. The signal output end of the sampling control unit is connected to the control pin of the switch tube. The method includes but is not limited to the following steps:

[0059] In step S610, the sampling current of the sampling resistor is obtained, and a driving signal corresponding to the sampling current is sent to the switch tube to control the on-off of the switch tube, so that the inductor unit discharges to the positive terminal of the direct current output end.

[0060] In the method, the sampling resistor is integrated near the direct current output end by connecting the sampling resistor in parallel with the rectifier module and the negative terminal of the direct current output end. The sampling control module is connected in parallel with the sampling resistor, and the signal output end of the sampling control module is directly connected to the control pin of the switch tube, so that the current information is obtained in real time and the switch tube is controlled to be on or off. One end of the sampling resistor is grounded, and the alternating current input end is connected through the switch tube. The on-off of the switch tube is controlled by the sampling control module according to the current information. The sampling resistor and the sampling control module are arranged near the direct current output end. The sampling control module has sampling and control functions, and includes a sampling unit and a driving unit, so that the non-isolated combination of the sampling unit and the driving unit is realized, the circuit integration is improved, the miniaturization design is facilitated, the separate current transformer or Hall sensor is saved, the additional modules and wiring are reduced, and the cost is reduced.

[0061] In a third aspect, the embodiments of the present application provide a power factor correction control device including the power factor correction control circuit according to any one of the embodiments of the first aspect. The power factor correction control device provided by the embodiments of the present application has at least the following beneficial effects: the sampling resistor is integrated near the direct current output end by connecting the sampling resistor in parallel with the rectifier module and the negative terminal of the direct current output end in the control device. The sampling control module is connected in parallel with the sampling resistor, and the signal output end of the sampling control module is directly connected to the control pin of the switch tube, so that the current information is obtained in real time and the switch tube is controlled to be on or off. One end of the sampling resistor is grounded, and the alternating current input end is connected through the switch tube. The on-off of the switch tube is controlled by the sampling control module according to the current information. The sampling resistor and the sampling control module are arranged near the direct current output end. The sampling control module has sampling and control functions, and includes a sampling unit and a driving unit, so that the non-isolated combination of the sampling unit and the driving unit is realized, the circuit integration is improved, the miniaturization design is facilitated, the separate current transformer or Hall sensor is saved, the additional modules and wiring are reduced, and the cost is reduced.

[0062] In a fourth aspect, the embodiments of the present application provide a household appliance comprising the power factor correction control device according to any one of the embodiments of the third aspect. The household appliance according to the embodiments of the present application has at least the following beneficial effects: the household appliance according to the present application integrates the sampling resistor near the DC output end by connecting the sampling resistor in parallel with the negative terminal of the DC output end of the rectifier module; the sampling control module is connected in parallel with the sampling resistor, and the signal output end of the sampling control module is directly connected with the control pin of the switch tube, so that the current information can be obtained in real time and the switch tube can be controlled to turn on and off; one end of the sampling resistor is connected with the ground, and the other end of the sampling resistor is connected with the AC input end through the switch tube, and the on-off of the switch tube is controlled by the sampling control module according to the current information; the sampling resistor and the sampling control module are both arranged near the DC output end, the sampling control module has the functions of sampling and control, and includes a sampling unit and a driving unit, so that the non-isolated combination of the sampling unit and the driving unit is realized, the circuit integration is improved, the miniaturization design is facilitated, the separate current transformer or Hall sensor is saved, the additional modules and wiring are reduced, and the cost is reduced.

[0063] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application can be realized and attained by the structure particularly pointed out in the description, claims and drawings.

[0064] The embodiments of the present application are described in detail above with reference to the drawings, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present application.

Claims

1. A power factor correction control circuit, comprising an AC input terminal, a rectifier module, and a DC output terminal connected in sequence, wherein: A sampling resistor and a sampling control module are connected in parallel between the rectifier module and the negative terminal of the DC output terminal. The end of the sampling resistor closest to the DC output terminal is grounded and connected to the AC input terminal via a switching transistor. An inductor is provided between the AC input terminal and the switching transistor. The signal output terminal of the sampling control unit is connected to the control pin of the switching transistor. The sampling control module is used to acquire the sampling current of the sampling resistor and send the driving signal corresponding to the sampling current to the switching transistor to control the switching transistor to turn it on and off, so that the inductor unit discharges to the positive terminal of the DC output terminal.

2. The control circuit for power factor correction according to claim 1, wherein, The sampling control module includes a sampling unit and a driving unit. The first voltage terminal of the sampling unit and the driving unit is connected to the end of the sampling resistor near the rectifier module, and the second voltage terminal of the sampling unit and the driving unit is connected to the end of the sampling resistor near the DC output terminal. The sampling unit is used to acquire the voltage signal of the sampling resistor and obtain the sampling current based on the voltage signal. The first signal output terminal of the driving unit is connected to the control pin of the switching transistor, and the driving unit is used to send the driving signal based on the control signal corresponding to the received sampling current.

3. The power factor correction control circuit according to claim 2 further includes a control unit connected to the sampling unit and the driving unit respectively, wherein the control unit is used to acquire the sampling current and send the control signal to the driving unit based on the voltage signal.

4. The control circuit for power factor correction according to claim 3, wherein, The input timing of the drive unit receiving the control signal and the output timing of sending the drive signal are the same. When the control signal is a high-level signal, the drive signal is a high-level signal, and the switch is turned on; when the control signal is a low-level signal, the drive signal is a low-level signal, and the switch is turned off.

5. The power factor correction control circuit according to claim 3 or 4, wherein, The second signal output terminal of the driving unit is connected to the control unit. The driving unit is also used to acquire the voltage signal of the sampling resistor. When the voltage signal is greater than or equal to a preset voltage threshold, an overcurrent signal is sent to the control unit through the second signal output terminal so that the control unit can perform overcurrent fault handling.

6. The control circuit for power factor correction according to any one of claims 1 to 5, wherein, The end of the switching transistor closest to the AC input terminal is connected to the live wire of the AC input terminal via a first diode, and to the neutral wire of the AC input terminal via a second diode. The negative terminals of both the first and second diodes are close to the switching transistor.

7. The control circuit for power factor correction according to claim 6, wherein, The inductor unit is disposed between the live wire terminal and the first diode; or, the inductor unit is disposed between the neutral wire terminal and the second diode.

8. The control circuit for power factor correction according to any one of claims 1 to 7, wherein, The sampling resistor includes a non-inductive resistor.

9. The control circuit for power factor correction according to any one of claims 1 to 8, wherein, The switching transistor includes an insulated gate bipolar transistor.

10. A control method for a power factor correction circuit, applied to a sampling control module in a power factor correction control circuit, wherein the control circuit includes an AC input terminal, a rectifier module, and a DC output terminal connected in sequence; a sampling resistor and a sampling control module are connected in parallel between the rectifier module and the negative terminal of the DC output terminal; one end of the sampling resistor near the DC output terminal is grounded and connected to the AC input terminal through a switching transistor; an inductor unit is provided between the AC input terminal and the switching transistor; and the signal output terminal of the sampling control unit is connected to the control pin of the switching transistor; and the method includes: The sampling current of the sampling resistor is obtained, and the driving signal corresponding to the sampling current is sent to the switching transistor to control the switching transistor to turn it on and off, so that the inductor unit discharges to the positive terminal of the DC output terminal.

11. A power factor correction control device, comprising a power factor correction control circuit as described in any one of claims 1 to 9.

12. A household appliance, comprising the power factor correction control device as described in claim 11.

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