Power factor compensation circuit and household appliance

Abstract

The embodiment of the invention provides a power factor compensation circuit and a household electrical appliance, and the circuit comprises a rectification module which is connected to an AC power supply; the first end of the switching device is electrically connected with the first output end of the rectification module, and the second end of the switching device is electrically connected with the second output end of the rectification module through the capacitor device; the first end of the load circuit is connected to the first end of the switching device, and the second end of the load circuit is connected to the second output end of the rectifier module; the controller is electrically connected with the control end of the switching device; wherein when the controller inputs a control signal to the control end of the switching device, the capacitor device supplies power to the load circuit; and when the controller does not input the control signal to the switching device, the capacitor device stops supplying power to the load circuit and charges the load circuit through the direct current output by the rectifier module. According to the technical scheme, reactive power generated in the load circuit can be reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electromechanical control, in particular to a power factor compensation circuit and a household appliance. BACKGROUND

[0002] With the improvement of people's living standards, people assist in performing household labor or optimizing the living environment through household appliances has become one of the common ways. For example, using cleaning appliances to perform household cleaning labor, using refrigeration appliances to improve the living environment or preserve food, using kitchen appliances to cook food, etc.

[0003] In the related art, when there is an inductive load or a capacitive load in the electrical equipment, reactive power is generated in the electrical equipment, causing the corresponding power factor of the electrical equipment to decrease, that is, the utilization rate of the electrical equipment for resources decreases.

[0004] Therefore, how to reduce the reactive power generated in the electrical equipment has become a problem to be solved. SUMMARY

[0005] Embodiments of the present application provide a power factor compensation circuit, which aims to solve the above technical problems.

[0006] The purpose of the present application is also to prolong the service life of the capacitor device for boosting the input voltage of the load circuit.

[0007] The purpose of the present application is also to ensure that the capacitor device boosts the input voltage of the load circuit when reactive power is generated in the electrical equipment.

[0008] The purpose of the present application is not limited to the above-mentioned purposes, and those skilled in the art can understand other purposes not mentioned by the following description.

[0009] According to an aspect of an embodiment of the present application, a power factor compensation circuit is provided, the circuit comprising: a rectification module connected to an alternating current power supply, for converting alternating current provided by the alternating current power supply into direct current; a switching device, a first end of the switching device being electrically connected to a first output end of the rectification module, a second end of the switching device being electrically connected to a second output end of the rectification module through a capacitor device; a load circuit, a first end of the load circuit being connected to the first end of the switching device, a second end of the load circuit being connected to the second output end of the rectification module; a controller, the controller being electrically connected to a control end of the switching device; wherein when the controller inputs a control signal to the control end of the switching device, the capacitor device supplies power to the load circuit; when the controller does not input a control signal to the switching device, the capacitor device stops supplying power to the load circuit, and charges through the direct current output by the rectification module.

[0010] In an embodiment of the present application, based on the foregoing scheme, the switching device includes an insulated gate bipolar transistor, an emitter stage of the insulated gate bipolar transistor is electrically connected with the first output end of the rectifier module, and a collector of the insulated gate bipolar transistor is electrically connected with the second output end of the rectifier module through the capacitor device.

[0011] In an embodiment of the present application, based on the foregoing scheme, the switching device includes a switching unit and a freewheeling diode; a first end of the switching unit is electrically connected with the first output end of the rectifier module, and a second end of the switching unit is electrically connected with the second output end of the rectifier module through the capacitor device; a positive electrode of the freewheeling diode is electrically connected with the first end of the switching unit, and a negative electrode of the freewheeling diode is electrically connected with the second end of the switching unit.

[0012] In an embodiment of the present application, based on the foregoing scheme, the switching unit includes at least one of a field effect tube, a triode, and a relay switch.

[0013] In an embodiment of the present application, based on the foregoing scheme, the first end of the switching device is electrically connected with the first output end of the rectifier module through the inductor device.

[0014] In an embodiment of the present application, based on the foregoing scheme, the circuit further includes a pre-power-on switch; the pre-power-on switch is arranged in series between the first end of the switching device and the first output end of the rectifier module; the first end of the load circuit is electrically connected with the first end of the switching device through the pre-power-on switch; the controller is further electrically connected with a control end of the pre-power-on switch, and the controller is configured to perform the following steps: when the input voltage of the rectifier module reaches a preset power-on threshold value, the pre-power-on switch is controlled to be turned on, and when the input voltage of the rectifier module exceeds the preset power-on threshold value, the pre-power-on switch is controlled to be turned off.

[0015] In an embodiment of the present application, based on the foregoing scheme, the controller is configured to perform the following steps: determining that the load circuit is in an under-voltage working condition according to the input voltage limit value corresponding to the load circuit and the output voltage of the rectifier module; and controlling the input of the control signal corresponding to the under-voltage working condition to the switching device.

[0016] In an embodiment of the present application, based on the foregoing scheme, the controller is configured to perform the following steps: determining that the load circuit is in an under-voltage working condition according to the input voltage limit value corresponding to the load circuit and the output voltage of the rectifier module; and controlling the input of the control signal corresponding to the under-voltage working condition to the switching device.

[0017] In an embodiment of the present application, based on the foregoing scheme, after determining that the load circuit is in an under-voltage working condition, the controller is further configured to perform the following steps: obtaining a voltage difference value between the input voltage limit value corresponding to the load circuit and the output voltage of the rectifier module; and taking the control signal corresponding to the voltage difference value as the control signal corresponding to the under-voltage working condition.

[0018] The details of other embodiments are included in the detailed description and the accompanying drawings.

[0019] According to at least one of the embodiments of the present application, when the controller inputs the control signal to the control end of the switching device, the capacitor device can supply power to the load circuit, so that the capacitor device can boost the input voltage of the load circuit, thereby achieving the purpose of reducing the reactive power generated in the load circuit through the boosted input voltage. Meanwhile, the power factor compensation circuit in the embodiments of the present application also has the advantages of small size, few electrical components, etc., effectively reducing the cost of applying the power factor compensation circuit in the electrical equipment.

[0020] According to at least one of the embodiments of the present application, when the controller determines that the input voltage of the rectifier module reaches the preset power-on threshold, it means that the input voltage of the rectifier module is decreasing and approaching the input voltage limit of the load circuit, so the pre-power-on switch can be controlled to be turned on, so that the path between the switching device and the capacitor device and the rectifier module is restored, so that the capacitor device is pre-charged by the direct current output by the rectifier module, thereby the capacitor device can supply power to the load circuit in time after the controller inputs the control signal to the switching device. When the controller determines that the input voltage of the rectifier module exceeds the preset power-on threshold, it means that the input voltage of the rectifier module is rising and to some extent exceeds the input voltage limit of the load circuit, so the pre-power-on switch can be controlled to be turned off, so that the path between the switching device and the capacitor device and the rectifier module is disconnected, thereby avoiding the capacitor device from being broken down when the input voltage of the rectifier module is too high or the voltage fluctuation of the alternating current power supply is large, so as to prolong the service life of the capacitor device.

[0021] According to at least one of the embodiments of the present application, the controller can first determine that the load circuit is in an under-voltage condition according to the voltage limit corresponding to the load circuit and the output voltage of the rectifier module, and then control the input of the control signal corresponding to the under-voltage condition to the switching device, so that the capacitor device can supply power to the load circuit through the control signal when the load circuit is in the under-voltage condition, thereby boosting the input voltage of the load circuit, so that the input voltage of the load circuit is not lower than the input voltage limit, and further ensuring that the capacitor device boosts the input voltage of the load circuit when the reactive power is generated in the electrical equipment, thereby reducing the reactive power generated in the load circuit.

[0022] According to an aspect of the embodiments of the present application, a household appliance is provided, comprising: a variable frequency motor; and a power factor compensation circuit according to any of the above embodiments, the variable frequency motor being included in the load circuit of the power factor compensation circuit, and the power factor compensation circuit being used for controlling the variable frequency motor.

[0023] The effects of the present application are not limited to the above-mentioned effects, and other effects not mentioned by the skilled in the art can be clearly understood from the description of the claims.

[0024] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings:

[0026] Figure 1 This is a schematic diagram of a power factor compensation circuit provided in an exemplary embodiment of this application.

[0027] Figure 2 This is a schematic diagram of the structure of a rectifier module shown in an exemplary embodiment of this application.

[0028] Figure 3 This is a schematic diagram of the structure of a rectifier module shown in another exemplary embodiment of this application.

[0029] Figure 4 This is a schematic diagram of the structure of a rectifier module shown in another exemplary embodiment of this application.

[0030] Figure 5 This is a schematic diagram illustrating the connection of a switching device and a capacitor in an exemplary embodiment of this application.

[0031] Figure 6 This is a schematic diagram illustrating the connection of the switching device and the capacitor, which is another exemplary embodiment of this application.

[0032] Figure 7 This is a schematic diagram illustrating the connection of an insulated gate bipolar transistor, as shown in an exemplary embodiment of this application.

[0033] Figure 8 This is a schematic diagram illustrating the connection between the switching unit and the freewheeling diode, as shown in an exemplary embodiment of this application.

[0034] Figure 9 This is a schematic diagram of the connection of the load circuit shown in an exemplary embodiment of this application.

[0035] Figure 10 This is a schematic diagram of the connection of the load circuit shown in another exemplary embodiment of this application.

[0036] Figure 11 This is a schematic diagram illustrating the connection of a pre-energized switch, as shown in an exemplary embodiment of this application.

[0037] Figure 12 Is Figures 1-10 The flowchart provides a control method for a power factor compensation circuit based on the above. Detailed Implementation

[0038] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0039] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0040] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0041] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0042] It should be noted that "multiple" in this article refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0043] When electrical equipment in related technologies contains inductive or capacitive loads, reactive power is generated within the equipment, causing a decrease in the power factor, which indicates a reduction in the equipment's resource utilization efficiency. Therefore, reducing the reactive power generated within electrical equipment has become an urgent problem to be solved.

[0044] To address the aforementioned problems, this application provides a power factor compensation circuit 100. Figure 1 This is a schematic diagram of the structure of a power factor compensation circuit 100 provided in an exemplary embodiment of this application.

[0045] like Figure 1 As shown, the power factor compensation circuit 100 may include a rectifier module 110. The rectifier module 110 is connected to the AC power supply 120 and can be used to convert the AC power supplied by the AC power supply 120 into DC power.

[0046] In some embodiments of this application, the rectifier module 110 may include a half-wave rectifier circuit. (See also...) Figure 2 As shown, the half-wave rectifier circuit may include a rectifier diode D1. The positive terminal of the rectifier diode D1 is connected to one end of the AC power supply 120 to limit the current output by the AC power supply 120 to flow in only one direction, thereby converting the AC current whose current direction changes with time into the DC current that flows in one direction.

[0047] In some embodiments of this application, the rectifier module 110 may include a full-wave rectifier circuit. (See also...) Figure 3 As shown, the full-wave rectifier circuit may include rectifier diodes D2 and D3. The anodes of rectifier diodes D2 and D3 are connected to the two current output terminals of AC power supply 120, respectively. The anodes of rectifier diodes D2 and D3 are connected to each other to restrict the current output by AC power supply 120 to flow in only one direction, thereby converting the alternating current whose current direction changes with time into direct current that flows in one direction.

[0048] In some embodiments of this application, the rectifier module 110 may include a bridge rectifier circuit. (See also...) Figure 4 As shown, the bridge rectifier circuit may include rectifier diodes D4, D5, D6, and D7. The negative terminals of rectifier diodes D4 and D6 are connected together, the positive terminals of D4 and D5 are connected together, the positive terminals of D5 and D7 are connected together, and the negative terminals of D7 and D6 are connected together. One current output terminal of the AC power supply 120 is connected between the negative terminal of rectifier diode D5 and the positive terminal of rectifier diode D4, and the other current output terminal of the AC power supply 120 is connected between the negative terminal of rectifier diode D7 and the positive terminal of rectifier diode D6. This design restricts the current output by the AC power supply 120 to flow in only one direction, thereby converting the alternating current (AC) whose current direction changes over time into direct current (DC) with unidirectional flow.

[0049] Reference Figure 1As shown, the power factor compensation circuit 100 may include a switching device 130 and a capacitor 140. The switching device 130 is used to conduct under the control of a control signal so that the capacitor 140 increases the output voltage of the rectifier module 110.

[0050] In some embodiments of this application, the connection method of the switching device 130 and the capacitor 140 can be referred to Figure 5 As shown, the first end of the switching device 130 can be electrically connected to the first output end of the rectifier module 110, and the second end of the switching device 130 can be electrically connected to the second output end of the rectifier module 110 through the capacitor 140, so that when the switching device 130 is turned on under the control of the control signal, it forms a path with the rectifier module 110, and the voltage value output by the rectifier module 110 is increased through the capacitor 140.

[0051] In some embodiments of this application, the connection method of the switching device 130 and the capacitor 140 can be referred to Figure 6 As shown, the first end of the switching device 130 can be electrically connected to the first output end of the rectifier module 110 through an inductor, and the second end of the switching device 130 can be electrically connected to the second output end of the rectifier module 110 through a capacitor 140, so as to reduce the harmonic interference generated by the AC power supply 120 through the inductor, thereby improving the stability and service life of the capacitor 140.

[0052] Secondly, in some embodiments of this application, the switching device 130 may include an insulated-gate bipolar transistor (IGBT). Correspondingly, the emitter of the IGBT is the first terminal of the switching device 130, and the collector of the IGBT is the second terminal of the switching device 130. Specific connection methods can be referred to... Figure 7 As shown, the emitter of the insulated-gate bipolar transistor Q1 can be electrically connected to the first output terminal of the rectifier module 110, and the collector of the insulated-gate bipolar transistor Q1 can be electrically connected to the second output terminal of the rectifier module 110 through the capacitor 140, so that when the insulated-gate bipolar transistor Q1 is turned on under the control of the control signal, it can form a path with the rectifier module 110 and increase the voltage value output by the rectifier module 110 through the capacitor 140. When the insulated-gate bipolar transistor Q1 does not receive the control signal, the capacitor 140 can be charged by the DC power output by the rectifier module 110.

[0053] In some embodiments of this application, the switching device 130 may include a switching unit and a freewheeling diode. Correspondingly, the first terminal of the switching unit and the positive terminal of the freewheeling diode are the first terminals of the switching device, and the second terminal of the switching unit and the negative terminal of the freewheeling diode are the second terminals of the switching device. Specific connection methods can be referred to... Figure 8As shown, the first terminal of the switching unit 150 can be electrically connected to the first output terminal of the rectifier module 110, and the second terminal of the switching unit 150 can be electrically connected to the second output terminal of the rectifier module 110 through the capacitor 140. The positive terminal of the freewheeling diode D8 is electrically connected to the first terminal of the switching unit 150, and the negative terminal of the freewheeling diode D8 is electrically connected to the second terminal of the switching unit 150, so that when the switching unit 150 is turned on under the control of the control signal, it can form a path with the rectifier module 110 and increase the voltage value output by the rectifier module 110 through the capacitor 140. When the switching unit 150 does not receive the control signal, the capacitor 140 can be charged by the DC power output by the rectifier module 110 through the freewheeling diode D8.

[0054] In addition, in some embodiments of this application, the switching unit 150 may include a field-effect transistor (FET), with the source of the FET being the first terminal of the switching unit 150 and the drain of the FET being the second terminal of the switching unit 150.

[0055] In some embodiments of this application, the switching unit 150 may include a transistor, with the collector of the transistor being the first terminal of the switching unit 150 and the emitter of the transistor being the second terminal of the switching unit 150.

[0056] In some embodiments of this application, the switching unit 150 may include a relay, and correspondingly, the input terminal of the relay is the first terminal of the switching unit 150, and the output terminal of the relay is the second terminal of the switching unit 150.

[0057] Reference Figure 1 As shown, the power factor correction circuit 100 may include a load circuit 160. The load circuit 160 is connected to the switching device 130.

[0058] In some embodiments of this application, the connection method of the load circuit 160 can be referred to Figure 9 As shown, the first terminal of the load circuit 160 can be connected to the first terminal of the switching device 130, and the second terminal of the load circuit 160 can be grounded, so that when the switching device 130 is disconnected under the control of the control signal, a path is formed between it and the rectifier module 110, that is, the load circuit 160 is powered and operates through the rectifier module 110; at the same time, when the switching device 130 is turned on under the control of the control signal, a path is formed between it and the rectifier module 110 and the capacitor 140, that is, the load circuit 160 is powered and operates through the rectifier module 110 and the capacitor 140.

[0059] In some embodiments of this application, in order to form a path between the load circuit 160 and the rectifier module 110, a path can also be directly established between the switching device 130 and the rectifier module 110. Specifically, please refer to... Figure 10As shown, the first end of the load circuit 160 can be connected to the first end of the switching device 130, and the second end of the load circuit 160 can be connected to the second output end of the rectifier module 110, so as to reduce the setting of grounding points in the circuit and save production costs.

[0060] Reference Figure 1 As shown, the power factor compensation circuit 100 may include a controller 170. The controller 170 may be electrically connected to the control terminal of the switching device 130 to control the switching device 130 to conduct. Specifically, when the controller 170 inputs a control signal to the control terminal of the switching device 130, the capacitor 140 may supply power to the load circuit 160, so that the capacitor 140 can increase the input voltage of the load circuit 160, thereby reducing the reactive power generated in the load circuit 160 through the boosted input voltage. Meanwhile, the power factor compensation circuit 100 provided in the above embodiments of this application also has the advantages of small size and few electrical components, effectively reducing the cost of applying the power factor compensation circuit 100 in electrical equipment.

[0061] When the controller 170 does not input a control signal to the switching device 130, the capacitor 140 can stop supplying power to the load circuit 160 and can be charged by the DC power output by the rectifier module 110, ensuring that when the controller 170 inputs a control signal to the switching device 130 again, the capacitor 140 can promptly increase the input voltage of the load circuit 160.

[0062] To illustrate, in order to execute a preset control program on the controller, the controller internally includes a storage module for storing the control program. This storage module can include internal memory and external memory. The internal memory is located inside the controller, while the external memory is electrically connected to the controller. Both the internal and external memory are used for writing and reading the control program, as well as storing execution parameters. For example, the internal memory is typically directly connected to the MCU (Microcontroller Unit) corresponding to the controller. Its storage capacity is generally small, but due to its direct connection to the MCU, its speed is relatively fast. In this application, the internal memory is used to store the instructions and data of the currently running program and directly exchange information with the MCU. The internal memory consists of many storage units, each capable of storing a binary number or an instruction represented by binary code. The internal memory is composed of random access memory (RAM) and read-only memory (ROM). External memory refers to memory other than the controller's internal memory and MCU cache. Such memory generally retains data even after power is off, such as hard drives, floppy disks, optical disks, and USB flash drives.

[0063] It should be understood that, above Figures 1-10This is merely a schematic diagram of an exemplary power factor compensation circuit and does not imply any limitation on its structure. In practical applications, the power factor compensation circuit may include... Figures 1-10 The different components of the structure shown, such as those including... Figures 1-10 The structure shown may have more or fewer components, without limitation.

[0064] Additionally, the controller can be configured to perform the following step two.

[0065] The load circuit is determined to be in an undervoltage condition based on the input voltage limit corresponding to the load circuit and the output voltage of the rectifier module.

[0066] The control inputs the control signal corresponding to the undervoltage condition to the switching device.

[0067] First, it should be noted that the input voltage limit for the load circuit represents the voltage value required for the load circuit to operate normally. In other words, if the input voltage of the load circuit is not lower than the input voltage limit, it indicates that the load circuit is operating normally. The input voltage of the load circuit can represent the DC bus voltage output by the power factor compensation circuit, i.e., the output voltage of the rectifier module or the combined output voltage of the rectifier module and capacitors.

[0068] In the embodiments of this application, in order to reduce the reactive power generated in the electrical equipment, the controller can first determine that the load circuit is in an undervoltage condition based on the input voltage limit corresponding to the load circuit and the output voltage of the rectifier module. The undervoltage condition is the operating condition in which the load circuit generates reactive power.

[0069] The method for determining whether a load circuit is in an undervoltage condition based on its input voltage limit and the rectifier module's output voltage can be flexibly configured as needed. In one example, undervoltage can be determined by checking whether the load circuit's input voltage limit exceeds the rectifier module's output voltage. Specifically, if the load circuit's input voltage limit exceeds the rectifier module's output voltage, it is determined to be in an undervoltage condition. Conversely, if the load circuit's input voltage limit does not exceed the rectifier module's output voltage, it is determined not to be in an undervoltage condition.

[0070] In another example, the duration for which the input voltage limit corresponding to the load circuit exceeds the output voltage of the rectifier module can be timed. When the timer reaches a first preset duration, the load circuit is determined to be in an undervoltage condition. Conversely, the duration for which the input voltage limit corresponding to the load circuit does not exceed the output voltage of the rectifier module can also be timed. When the timer reaches a second preset duration, the load circuit is determined not to be in an undervoltage condition. This is to avoid interference from brief fluctuations in the AC power supplied by the AC power source in determining whether the load circuit is in an undervoltage condition, thereby improving the accuracy of determining whether the load circuit is in an undervoltage condition.

[0071] In another example, to prevent short-term fluctuations in the AC power supply from interfering with the process of determining whether the load circuit is undervoltage, the undervoltage condition can be determined by checking whether the voltage difference between the input voltage limit of the load circuit and the output voltage of the rectifier module exceeds a preset voltage threshold. Specifically, if the voltage difference between the input voltage limit of the load circuit and the output voltage of the rectifier module exceeds the preset voltage threshold, the load circuit is determined to be undervoltage. Conversely, if the voltage difference between the input voltage limit of the load circuit and the output voltage of the rectifier module does not exceed the preset voltage threshold, the load circuit is determined not to be undervoltage, thereby improving the accuracy of determining whether the load circuit is undervoltage.

[0072] In the above process, after determining that the load circuit is in an undervoltage condition, the controller can control the input of a control signal corresponding to the undervoltage condition to the switching device, so that the capacitor can increase the input voltage of the load circuit. The control signal is used to control the switching device to periodically turn on at its corresponding control frequency. For example, controlling the input of a pulse width modulation control signal corresponding to the undervoltage condition to the switching device.

[0073] In some embodiments of this application, after determining that the load circuit is in an undervoltage condition, the control signal corresponding to the undervoltage condition can be obtained first. The method for obtaining the control signal corresponding to the undervoltage condition can be flexibly set as needed. In one example, after determining that the load circuit is in an undervoltage condition, the control signal corresponding to the undervoltage condition can be directly obtained from a preset memory. That is, the preset memory can pre-store the control signal corresponding to the load circuit under the undervoltage condition, thereby facilitating the rapid acquisition of the control signal to control the switching device.

[0074] In another example, the voltage difference between the input voltage limit of the load circuit and the output voltage of the rectifier module can be obtained first. Then, the control signal corresponding to the voltage difference can be used as the control signal for the undervoltage condition. This allows the capacitor to input the corresponding voltage to the load circuit based on the voltage difference between the output voltage of the rectifier module and the input voltage limit after the control signal is input to the switching device. This enables the capacitor to release voltage to the load circuit only when the load circuit is in an undervoltage condition, thereby avoiding the waste of the charge stored in the capacitor.

[0075] Through the above implementation method, the controller can first determine that the load circuit is in an undervoltage condition based on the voltage limit corresponding to the load circuit and the output voltage of the rectifier module. Then, it controls the input of the control signal corresponding to the undervoltage condition to the switching device. The control signal enables the capacitor to supply power to the load circuit when the load circuit is in an undervoltage condition, thereby increasing the input voltage of the load circuit and ensuring that the input voltage of the load circuit is not lower than the input voltage limit, thereby achieving the purpose of reducing the reactive power generated by the load circuit.

[0076] In another exemplary embodiment, the power factor compensation circuit may further include a pre-energized switch, as shown in the reference. Figure 11 As shown, a pre-energized switch S1 is connected in series between the first terminal of the switching device and the first output terminal of the rectifier module. The first terminal of the load circuit is electrically connected to the first terminal of the switching device through the pre-energized switch S1. When the pre-energized switch S1 is on, a path is formed between the rectifier module and the capacitor, allowing the capacitor to be charged by the DC power output from the rectifier module. When the pre-energized switch is off, the path between the rectifier module and the capacitor is broken, thereby preventing voltage fluctuations from the AC power supply from damaging the capacitor.

[0077] In some embodiments of this application, the pre-energized switch may include electronic devices such as insulated-gate bipolar transistors, field-effect transistors, bipolar transistors, and relays used to control the on / off state of the circuit. The specific electronic device used as the pre-energized switch in the power factor compensation circuit can be flexibly configured according to the developer's needs and is not limited herein.

[0078] The controller can also be electrically connected to the control terminal of the pre-energized switch. Based on the electrical connection with the control terminal of the pre-energized switch, the controller can be configured to perform the following steps:

[0079] When the input voltage of the rectifier module reaches the preset power-on threshold, the pre-power-on switch is turned on. When the input voltage of the rectifier module exceeds the preset power-on threshold, the pre-power-on switch is turned off. The preset power-on threshold is greater than the input voltage limit.

[0080] In the embodiments of this application, when the controller determines that the input voltage of the rectifier module has reached the preset energizing threshold, it indicates that the input voltage of the rectifier module is decreasing and approaching the input voltage limit of the load circuit. The controller can then control the pre-energizing switch to turn on, so that the path between the switching device and the capacitor and the rectifier module is restored. This allows the capacitor to be pre-charged by the DC power output from the rectifier module, so that after the controller inputs a control signal to the switching device, the capacitor can supply power to the load circuit in a timely manner.

[0081] When the controller determines that the input voltage of the rectifier module exceeds the preset power-on threshold, it indicates that the input voltage of the rectifier module is rising and has exceeded the input voltage limit of the load circuit to a certain extent. The controller can then control the pre-power-on switch to turn off, thereby disconnecting the path between the switching devices and capacitors and the rectifier module. This prevents the capacitors from being damaged when the input voltage of the rectifier module is too high or the AC power supply voltage fluctuates greatly, thus extending the service life of the capacitors.

[0082] In addition, the preset power-on threshold can be flexibly set as needed. In one example, the preset power-on threshold can be calculated based on the input voltage limit corresponding to the load circuit and the preset coefficient.

[0083] In another example, considering that the input voltage limit of the load circuit is related to the operating power required by the current program of the load circuit, the preset power threshold corresponding to the operating power of the load circuit can be directly obtained.

[0084] In another example, to improve the lifespan of the capacitor, a preset energizing threshold can be determined based on the input voltage limit of the load circuit and the capacitance of the capacitor. This allows the capacitor to be fully charged by the DC current output from the rectifier module during the period when the output voltage of the rectifier module rises from the input voltage limit to the preset energizing threshold, thereby maintaining the capacitance performance of the capacitor.

[0085] Figure 12 This is a flowchart of a control method for a power factor compensation circuit provided in an embodiment of this application, in conjunction with the above. Figures 1-10 The provided schematic diagram of the power factor compensation circuit shows that the control method of the power factor compensation circuit may include the following steps S01-S04:

[0086] Step S01: Obtain the output voltage of the rectifier module.

[0087] Step S02: Determine whether the load circuit is in an undervoltage condition based on the input voltage limit corresponding to the load circuit and the output voltage of the rectifier module.

[0088] If it is determined to be yes, it indicates that the input voltage limit of the load circuit exceeds the output voltage of the rectifier module, and then step S03 is executed, that is, the control signal corresponding to the undervoltage condition is input to the switching device so that the capacitor supplies power to the load circuit, thereby increasing the input voltage of the load circuit so that the input voltage of the load circuit is not lower than the input voltage limit, thereby achieving the purpose of reducing the reactive power generated by the load circuit.

[0089] If the result is negative, it indicates that the output voltage of the rectifier module exceeds the input voltage limit of the load circuit. Then, step S04 is executed, which stops inputting control signals to the switching device so that the capacitor stops supplying power to the load circuit and charges it with the DC power output from the rectifier module. This ensures that the capacitor can supply power to the load circuit in a timely manner when the input voltage limit of the load circuit exceeds the output voltage of the rectifier module.

[0090] Alternatively, either step S03 or step S04 can jump to step S01 to repeat steps S01-S04 during the operation of the load circuit, thereby ensuring that the input voltage of the load circuit is always not lower than the input voltage limit during operation, thereby reducing the reactive power generated by the load circuit.

[0091] In some embodiments of this application, this application also provides a household appliance, which may include: a variable frequency motor; and a power factor compensation circuit as disclosed in any of the above embodiments, wherein the variable frequency motor is included in the load circuit, and the power factor compensation circuit is used to control the variable frequency motor.

[0092] Household appliances can refer to various electrical and electronic appliances used in daily household life. For example, household appliances can be refrigeration appliances, including refrigerators, freezers, beverage coolers, and air conditioners. Household appliances can also be cleaning appliances, primarily used for cleaning clothes and the home environment. This can include washing machines, dryers, and vacuum cleaners. Household appliances can also be kitchen appliances: devices used for cooking and food preparation, including rice cookers, microwave ovens, induction cookers, and electric ovens. The above are merely illustrative examples and do not constitute specific limitations.

[0093] Regarding the accompanying drawings of the various embodiments of this application, it should be noted that the flowcharts and block diagrams in the drawings illustrate the architecture, functions, and operations of possible implementations of systems, methods, and computer program products according to various embodiments of this application. Each block in a flowchart or block diagram may represent a module, program segment, or part of code, which includes one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than that shown in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0095] For ease of explanation, the above description has been provided in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed above. Various modifications and variations can be obtained based on the above teachings. The selection and description of the above embodiments are for the purpose of better explaining the principles and practical applications, thereby enabling those skilled in the art to better utilize the described embodiments and various different variations of embodiments suitable for specific use considerations.

Claims

1. A power factor compensation circuit, characterized in that, The circuit includes: A rectifier module, connected to an AC power source, is used to convert the AC power supplied by the AC power source into DC power; a switching device, the first terminal of which is electrically connected to the first output terminal of the rectifier module, and the second terminal of which is electrically connected to the second output terminal of the rectifier module through a capacitor; A load circuit, wherein a first terminal of the load circuit is connected to a first terminal of the switching device, and a second terminal of the load circuit is connected to a second output terminal of the rectifier module; The controller is electrically connected to the control terminal of the switching device; When the controller inputs a control signal to the control terminal of the switching device, the capacitor supplies power to the load circuit. When the controller does not input a control signal to the switching device, the capacitor stops supplying power to the load circuit and is charged by the DC power output from the rectifier module.

2. The power factor compensation circuit according to claim 1, characterized in that, The switching device includes an insulated-gate bipolar transistor (IGBT), the emitter of which is electrically connected to the first output terminal of the rectifier module, and the collector of which is electrically connected to the second output terminal of the rectifier module through the capacitor.

3. The power factor compensation circuit according to claim 1, characterized in that, The switching device includes a switching unit and a freewheeling diode; The first end of the switching unit is electrically connected to the first output end of the rectifier module, and the second end of the switching device is electrically connected to the second output end of the rectifier module through the capacitor. The positive terminal of the freewheeling diode is electrically connected to the first terminal of the switching unit, and the negative terminal of the freewheeling diode is electrically connected to the second terminal of the switching unit.

4. The power factor compensation circuit according to claim 3, characterized in that, The switching unit includes at least one of the following: a field-effect transistor, a transistor, or a relay switch.

5. The power factor compensation circuit according to claim 1, characterized in that, The first terminal of the switching device is electrically connected to the first output terminal of the rectifier module through an inductor.

6. The power factor compensation circuit according to claim 1, characterized in that, The circuit also includes a pre-energized switch; The pre-energized switch is connected in series between the first terminal of the switching device and the first output terminal of the rectifier module; The first terminal of the load circuit is electrically connected to the first terminal of the switching device through the pre-energized switch; The controller is also electrically connected to the control terminal of the pre-energized switch, and the controller is configured to perform the following steps: When the input voltage of the rectifier module reaches the preset power-on threshold, the pre-power-on switch is controlled to turn on, and when the input voltage of the rectifier module exceeds the preset power-on threshold, the pre-power-on switch is controlled to turn off.

7. The power factor compensation circuit according to claim 1, characterized in that, The controller is configured to perform the following steps: The load circuit is determined to be in an undervoltage condition based on the input voltage limit corresponding to the load circuit and the output voltage of the rectifier module. The control inputs the control signal corresponding to the undervoltage condition to the switching device.

8. The power factor compensation circuit according to claim 7, characterized in that, The step of determining that the load circuit is in an undervoltage condition based on the input voltage limit corresponding to the load circuit and the output voltage of the rectifier module includes: When the input voltage limit corresponding to the load circuit exceeds the output voltage of the rectifier module, the load circuit is determined to be in the undervoltage condition.

9. The power factor compensation circuit according to claim 8, characterized in that, After determining that the load circuit is in the undervoltage condition, the controller is further configured to perform the following steps: Obtain the voltage difference between the input voltage limit corresponding to the load circuit and the output voltage of the rectifier module; The control signal corresponding to the voltage difference is used as the control signal corresponding to the undervoltage condition.

10. A household appliance, characterized in that, include: Variable frequency motor; Furthermore, in the power factor compensation circuit as described in any one of claims 1-9, the variable frequency motor is included in the load circuit of the power factor compensation circuit, and the power factor compensation circuit is used to control the variable frequency motor.

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