Control method of power factor correction circuit, controller and electric equipment

Abstract

The invention discloses a control method of a power factor correction circuit, a controller and electric equipment, and the power factor correction circuit comprises a first bridge arm which comprises a first switching tube and a second switching tube which are connected in series; the second bridge arm comprises a third switching tube and a fourth switching tube which are connected in series; the control method comprises the following steps: under the condition that an alternating voltage crosses zero from a negative half cycle to a positive half cycle, controlling a second switch tube to be turned on for a first preset duration, controlling a third switch tube to be turned off, and turning on a fourth switch tube; and under the condition that the alternating voltage crosses zero from the positive half cycle to the negative half cycle, controlling the first switch tube to be turned on for a second preset duration, controlling the fourth switch tube to be turned off, and controlling the third switch tube to be turned on. According to the embodiment of the invention, the electric energy of the parasitic capacitor of the switching tube can be fully utilized, and the current impact caused by the discharge of the parasitic capacitor is avoided.

Description

Technical Field

[0001] The present application relates to the field of electronic circuits, and in particular to a control method, a controller and an electrical device for a power factor correction circuit. Background Art

[0002] The power factor correction circuit generally includes an inductor and two bridge arms. Two switching tubes in the same direction are arranged on the two bridge arms. The controller of the power factor correction circuit realizes the power factor correction of the load by controlling the switching action of the switching tube based on a certain frequency.

[0003] The cost of the switch tubes in the bridge arm that are controlled to switch the switch state quickly is relatively high. Therefore, in order to reduce the cost, for those switch tubes that do not need to switch the switch state quickly, low-cost switch tubes with slower switching response speed can be selected. However, these switch tubes with slower switching response speed often have large parasitic capacitance. When the circuit is working, when these switch tubes are controlled to turn on, the energy stored in the parasitic capacitance inside them will be released, resulting in current shock and other problems in the circuit, affecting the normal operation of the circuit. Summary of the invention

[0004] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a control method, a controller and an electrical device for a power factor correction circuit, which can fully utilize the electrical energy of the parasitic capacitance of the switch tube and avoid current shock caused by the discharge of the parasitic capacitance.

[0005] An embodiment of the first aspect of the present application provides a control method, wherein the power factor correction circuit includes:

[0006] The first bridge arm comprises a first switch tube and a second switch tube connected in series, wherein the first switch tube is used to switch the switch state multiple times in a positive half cycle of the AC voltage, and the second switch tube is used to switch the switch state multiple times in a negative half cycle of the AC voltage;

[0007] The second bridge arm comprises a third switch tube and a fourth switch tube connected in series, wherein the third switch tube and the fourth switch tube are used to controllably switch the switch state at the zero-crossing point of the AC voltage;

[0008] The control method comprises:

[0009] When the AC voltage passes through zero from the negative half cycle to the positive half cycle, the second switch tube is controlled to be turned on for a first preset time, the third switch tube is controlled to be turned off, and the fourth switch tube is controlled to be turned on;

[0010] When the AC voltage passes through zero from the positive half cycle to the negative half cycle, the first switch tube is controlled to be turned on for a second preset time length, the fourth switch tube is controlled to be turned off, and the third switch tube is controlled to be turned on.

[0011] The control method of the first aspect embodiment of the present application has at least the following beneficial effects: the first switch tube and the second switch tube are switch tubes that can be controlled to switch the switch state quickly, the third switch tube and the fourth switch tube are switch tubes with a slow switch response speed and a large parasitic capacitance, and the third switch tube and the fourth switch tube are controlled to switch the switch state only when they cross the zero point; when the AC voltage crosses zero from the negative half cycle to the positive half cycle, the fourth switch tube is controlled to be turned on, and the electric energy of the parasitic capacitance of the fourth switch tube needs to be released. In order to avoid the released electric energy from causing an impact on the circuit, the second switch tube is controlled to be turned on for a first preset time length, so that the electric energy of the parasitic capacitance of the fourth switch tube can be released into the inductance and capacitance of the power factor correction circuit. Similarly, when the AC voltage crosses zero from the positive half cycle to the negative half cycle, the third switch tube is controlled to be turned on, and the electric energy of the parasitic capacitance of the third switch tube needs to be released. In order to avoid the released electric energy from causing an impact on the circuit, the first switch tube is controlled to be turned on for a second preset time length, so that the electric energy of the parasitic capacitance of the third switch tube can be released into the inductance and capacitance of the power factor correction circuit. Through the above control method, the electric energy of the parasitic capacitor of the switch tube can be effectively utilized, and the electric energy can be finally transferred to the capacitor, and the problem of current shock caused by the release of electric energy by the parasitic capacitor is solved.

[0012] According to some embodiments of the present application, the first preset time length is determined according to the parasitic capacitance value of the fourth switch tube, and the second preset time length is determined according to the parasitic capacitance value of the third switch tube.

[0013] According to some embodiments of the present application, when the AC voltage passes through zero from the negative half cycle to the positive half cycle, controlling the second switch tube to turn on for a first preset time length includes:

[0014] Determine the first moment according to the moment when the AC voltage passes through zero from the negative half cycle to the positive half cycle;

[0015] Starting from the first moment, controlling the second switch tube to be turned on for a first preset time length;

[0016] When the AC voltage passes through zero from the positive half cycle to the negative half cycle, controlling the first switch tube to turn on for a second preset time period includes:

[0017] Determine the second moment according to the moment when the AC voltage passes through zero from the positive half cycle to the negative half cycle;

[0018] Starting from the second moment, the first switch tube is controlled to be turned on for a second preset time period.

[0019] According to some embodiments of the present application, the first moment is the moment when the AC voltage passes through zero from the negative half-cycle to the positive half-cycle, or the third moment before the AC voltage passes through zero from the negative half-cycle to the positive half-cycle; the second moment is the moment when the AC voltage passes through zero from the positive half-cycle to the negative half-cycle, or the fourth moment before the AC voltage passes through zero from the positive half-cycle to the negative half-cycle.

[0020] According to some embodiments of the present application, when the AC voltage passes through zero from the negative half cycle to the positive half cycle, controlling the second switch tube to turn on for a first preset time length includes:

[0021] In the negative half cycle of the AC voltage, the voltage value of the AC voltage is monitored;

[0022] When the voltage value of the AC voltage is lower than the first preset voltage value, controlling the second switch tube to open for a first preset time length;

[0023] When the AC voltage passes through zero from the positive half cycle to the negative half cycle, controlling the first switch tube to turn on for a second preset time period includes:

[0024] In the positive half cycle of the AC voltage, the voltage value of the AC voltage is monitored;

[0025] When the voltage value of the AC voltage is lower than the second preset voltage value, the first switch tube is controlled to be turned on for a second preset time period.

[0026] According to some embodiments of the present application, controlling the second switch tube to be turned on for a first preset time period includes:

[0027] The second switch tube is controlled to be turned on by a first conduction pulse, the duration of the first conduction pulse is a first preset duration, or the second switch tube is controlled to be turned on by multiple first conduction pulses, the total duration of the multiple first conduction pulses is the first preset duration;

[0028] The controlling the first switch tube to turn on for a second preset time period includes:

[0029] The first switch tube is controlled to turn on by a second conduction pulse, the duration of the second conduction pulse is a second preset duration, or the first switch tube is controlled to turn on by multiple second conduction pulses, the total duration of the multiple second conduction pulses is the second preset duration.

[0030] According to some embodiments of the present application, the power factor correction circuit is a totem pole circuit, which includes an inductor, and the middle connection point of the first bridge arm is connected to one phase of the AC voltage through the inductor, and the middle connection point of the second bridge arm is connected to another phase of the AC voltage.

[0031] According to some embodiments of the present application, the totem pole circuit further includes a capacitor, and the first bridge arm, the second bridge arm, and the capacitor are connected in parallel.

[0032] A second aspect of the present application provides a controller, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the control method described in the first aspect when executing the computer program.

[0033] A third aspect of the present application provides an electrical device, including the control method described in the first aspect and the controller described in the second aspect.

[0034] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained through the structures particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a circuit diagram of a power factor correction circuit provided by an embodiment of the present application;

[0036] Figure 2 This is a flow chart of a control method provided by an embodiment of the present application;

[0037] Figure 3 yes Figure 2 Specific flow chart of step S200;

[0038] Figure 4 yes Figure 2 Specific flow chart of step S300;

[0039] Figure 5 yes Figure 2 Another specific flow chart of step S200;

[0040] Figure 6 yes Figure 2 Another specific flow chart of step S300;

[0041] Figure 7 yes Figure 2 Another specific flow chart of step S200;

[0042] Figure 8 yes Figure 2 Another specific flow chart of step S300;

[0043] Fig. 9 It is a method flow chart of a control method provided by an example of the present application. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. In addition, the characteristics, operations or features described in the specification can be combined in any appropriate manner to form various implementation methods. At the same time, the steps or actions in the method description can also be replaced or adjusted in order in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the accompanying drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a necessary sequence, unless otherwise specified that a certain sequence must be followed.

[0045] In the description of this application, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0046] The serial numbers of the components in this document, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings).

[0047] The power factor correction circuit generally includes an inductor and two bridge arms. Two switching tubes in the same direction are arranged on the two bridge arms. The controller of the power factor correction circuit realizes the power factor correction of the load by controlling the switching action of the switching tube based on a certain frequency.

[0048] Due to the characteristics of the totem pole circuit, it is necessary to use switch tubes with small parasitic capacitance and fast reverse recovery characteristics, but such switch tubes are generally expensive. This leads to the high cost of the switch tubes in the bridge arm that are controlled to switch the switch state quickly. Therefore, in order to reduce costs, for those switch tubes that do not need to switch the switch state quickly, lower-cost switch tubes with slower switching response speeds can be selected. However, these switch tubes with slow switching response speeds often have large parasitic capacitance. When the circuit is working, when these switch tubes are controlled to turn on, the electric energy stored in the parasitic capacitance inside them will be released, resulting in current shock and other problems in the circuit, affecting the normal operation of the circuit.

[0049] From this we can see that using a switching tube with a slow switching response speed will not only sacrifice efficiency but also cause problems such as current shock, affecting circuit reliability.

[0050] Based on this, an embodiment of the present application provides a control method, a controller and an electrical device for a power factor correction circuit. The first switch tube and the second switch tube in the control method are switch tubes that can be controlled to switch the switch state quickly, and the third switch tube and the fourth switch tube are switch tubes with a slow switch response speed and a large parasitic capacitance. The third switch tube and the fourth switch tube are controlled to switch the switch state only when they cross the zero point; when the AC voltage crosses zero from the negative half cycle to the positive half cycle, the fourth switch tube is controlled to be turned on, and the electric energy of the parasitic capacitance of the fourth switch tube needs to be released. In order to avoid the released electric energy from causing an impact on the circuit, the second switch tube is controlled to be turned on for a first preset time, so that the electric energy of the parasitic capacitance of the fourth switch tube can be released into the inductance and capacitance of the power factor correction circuit. Similarly, when the AC voltage crosses zero from the positive half cycle to the negative half cycle, the third switch tube is controlled to be turned on, and the electric energy of the parasitic capacitance of the third switch tube needs to be released. In order to avoid the released electric energy from causing an impact on the circuit, the first switch tube is controlled to be turned on for a second preset time, so that the electric energy of the parasitic capacitance of the third switch tube can be released into the inductance and capacitance of the power factor correction circuit. Through the above control method, the electric energy of the parasitic capacitor of the switch tube can be effectively utilized, and the electric energy can be finally transferred to the capacitor, and the problem of current shock caused by the release of electric energy by the parasitic capacitor is solved.

[0051] The embodiments of the present application are further described below in conjunction with the accompanying drawings.

[0052] like Figure 1 As shown, Figure 1 : is a circuit diagram of a power factor correction circuit provided by an embodiment of the present application, the power factor correction circuit comprising:

[0053] The first bridge arm 100 includes a first switch tube Q1 and a second switch tube Q2 connected in series. In the positive half cycle of the AC voltage, the first switch tube Q1 is used to switch the switch state multiple times in a controlled manner. In the negative half cycle of the AC voltage, the second switch tube Q2 is used to switch the switch state multiple times in a controlled manner, so that the switch states of the first switch tube Q1 and the second switch tube Q2 can be switched in the positive half cycle and the negative half cycle of the AC voltage, and the switch states can be switched quickly with a short conversion time, thereby reducing power loss during the switching process of the switch states;

[0054] The second bridge arm 200 includes a third switch tube Q3 and a fourth switch tube Q4 connected in series, and the third switch tube Q3 and the fourth switch tube Q4 are used to control switching states at a zero-crossing point of the AC voltage, so that the switching process of the third switch tube Q3 and the fourth switch tube Q4 is more stable, and the cost of the switch tube is reduced;

[0055] It should be noted that the first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 in this embodiment can be MOS tubes, for example, PMOS tubes or NMOS tubes. This embodiment and the accompanying drawings are explained by taking the first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 as NMOS tubes. For example, Figure 1 In the circuit diagram shown, the first switch tube Q1 , the second switch tube Q2 , the third switch tube Q3 and the fourth switch tube Q4 are all NMOS tubes.

[0056] In some embodiments, the power factor correction circuit is a totem pole circuit, which includes an inductor L1, a middle connection point of the first bridge arm 100 is connected to one phase of the AC voltage through the inductor L1, and a middle connection point of the second bridge arm 200 is connected to another phase of the AC voltage.

[0057] The totem pole circuit further includes a capacitor C1, and the first bridge arm 100, the second bridge arm 200 and the capacitor C1 are connected in parallel.

[0058] It can be understood that the first bridge arm 100 is connected in parallel with the second bridge arm 200. When the first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 are all NMOS tubes, the source of the first switch tube Q1 is connected to the drain of the second switch tube Q2, the drain of the first switch tube Q1 is connected to the voltage output end, the source of the second switch tube Q2 is connected to the reference ground, the source of the third switch tube Q3 is connected to the drain of the fourth switch tube Q4, the drain of the third switch tube Q3 is connected between the first switch tube Q1 and the voltage output end, the source of the fourth switch tube Q4 is connected between the second switch tube Q2 and the reference ground, and the inductor L1 is connected between the source of the first switch tube Q1 and the drain of the second switch tube Q2.

[0059] It is worth noting that the first switch tube Q1 and the second switch tube Q2 in the present embodiment are switch tubes with faster switch response speeds, so that they can quickly switch the switch state, reduce the conversion time, and reduce the power loss in the process of switching the switch state. The third switch tube Q3 and the fourth switch tube Q4 are switch tubes with slower switch response speeds. The slower response speed makes the switching process of the switch tube more stable and reduces the cost of the switch tube.

[0060] It can be understood that when the AC voltage passes through zero from the negative half cycle to the positive half cycle, the first switch tube Q1 and the fourth switch tube Q4 are turned on, and the second switch tube Q2 and the third switch tube Q3 are turned off, and the inductor L1 of the power factor correction circuit is in a discharging state; the first switch tube Q1 and the third switch tube Q3 are turned off, and the second switch tube Q2 and the fourth switch tube Q4 are turned on, and the inductor L1 of the power factor correction circuit is in a charging state.

[0061] When the AC voltage passes through zero from the positive half cycle to the negative half cycle, the second switch tube Q2 and the third switch tube Q3 are turned on, and the first switch tube Q1 and the fourth switch tube Q4 are turned off. At this time, the inductor L1 of the power factor correction circuit is in a discharging state; the second switch tube Q2 and the fourth switch tube Q4 are turned off, and the first switch tube Q1 and the third switch tube Q3 are turned on. At this time, the inductor L1 of the power factor correction circuit is in a charging state.

[0062] It can be understood that the zero crossing from the negative half cycle to the positive half cycle and the zero crossing from the positive half cycle to the negative half cycle involved in the embodiments of the present application are defaulted to the phase change of the phase of the AC voltage input by the first bridge arm 100.

[0063] It can be understood that when the input AC voltage is commutated, Figure 1 The parasitic capacitance in the third switch tube Q3 or the fourth switch tube Q4 will store a certain amount of electrical energy, so the switch tube with a slower switching response speed generally uses a switch tube with a small parasitic capacitance and a fast reverse recovery characteristic. If the parasitic capacitance in the third switch tube Q3 or the fourth switch tube Q4 is too large, when the input voltage is switched, the third switch tube Q3 or the fourth switch tube Q4 will be turned on, resulting in energy waste and current shock.

[0064] Based on the structural diagram of the above power factor correction circuit, various embodiments of the control method of the present application are proposed.

[0065] like Figure 2 As shown, Figure 2 It is a flowchart of a control method provided by an embodiment of the present application, and the control method includes but is not limited to steps S100 to S300.

[0066] Step S100, detecting AC voltage;

[0067] Step S200, when the AC voltage passes through zero from the negative half cycle to the positive half cycle, the second switch tube Q2 is controlled to be turned on for a first preset time, the third switch tube Q3 is controlled to be turned off, and the fourth switch tube Q4 is controlled to be turned on;

[0068] In some embodiments, the AC voltage of the power factor correction circuit is detected, wherein the detection of the AC voltage includes but is not limited to detecting the voltage magnitude and voltage direction of the AC voltage. When the AC voltage passes through zero from the negative half cycle to the positive half cycle, that is, the input AC voltage changes phase, the parasitic capacitance of the fourth switch tube Q4 will store a certain amount of electrical energy, and the second switch tube Q2 is controlled to be turned on for a first preset time, and the third switch tube Q3 is controlled to be turned off and the fourth switch tube Q4 is controlled to be turned on, so as to avoid the influence of the parasitic capacitance of the third switch tube Q3, and by turning on the second switch tube Q2 to prepare for low-frequency rectification, the energy release of the parasitic capacitance of the fourth switch tube Q4 can be avoided from causing an impact on the circuit, so that the energy of the parasitic capacitance of the fourth switch tube Q4 can be released into the inductance and capacitance of the power factor correction circuit, so that the energy of the parasitic capacitance of the fourth switch tube Q4 can be fully utilized, and the energy release of the parasitic capacitance of the fourth switch tube Q4 can be avoided from causing an impact on the circuit, thereby improving the reliability of the circuit.

[0069] It should be noted that when the AC voltage passes through zero from the negative half-cycle to the positive half-cycle, the first switch tube Q1 can be controlled to turn on or off. When the first switch tube Q1 is turned on, the inductance of the power factor correction circuit is in a discharging state; when the first switch tube Q1 is turned off, the inductance of the power factor correction circuit is in a charging state.

[0070] Step S300, when the AC voltage passes through zero from the positive half cycle to the negative half cycle, the first switch tube Q1 is controlled to be turned on for a second preset time, the fourth switch tube Q4 is controlled to be turned off, and the third switch tube Q3 is controlled to be turned on.

[0071] In some embodiments, when the AC voltage passes through zero from the positive half cycle to the negative half cycle, the parasitic capacitance of the third switch tube Q3 will store a certain amount of electric energy, and the first switch tube Q1 is controlled to be turned on for a first preset time, and the fourth switch tube Q4 is controlled to be turned off and the third switch tube Q3 is turned on to avoid the influence of the parasitic capacitance of the fourth switch tube Q4. By turning on the first switch tube Q1 to prepare for low-frequency rectification, the electric energy release of the parasitic capacitance of the third switch tube Q3 can be avoided from causing an impact on the circuit, so that the electric energy of the parasitic capacitance of the third switch tube Q3 can be released into the inductance and capacitance of the power factor correction circuit, so that the electric energy of the parasitic capacitance of the third switch tube Q3 can be fully utilized, and the electric energy release of the parasitic capacitance of the third switch tube Q3 can be avoided from causing an impact on the circuit, thereby improving the reliability of the circuit.

[0072] It should be noted that when the AC voltage passes through zero from the positive half-cycle to the negative half-cycle, the second switch tube Q2 can be controlled to turn on or off. When the second switch tube Q2 is turned on, the inductance of the power factor correction circuit is in a discharging state; when the second switch tube Q2 is turned off, the inductance of the power factor correction circuit is in a charging state.

[0073] In some embodiments, the first preset time length is determined according to the parasitic capacitance value of the fourth switch tube Q4, and the second preset time length is determined according to the parasitic capacitance value of the third switch tube Q3, so that the working state of the second switch tube Q2 can be controlled according to the first preset time length, and the working state of the first switch tube Q1 can be controlled according to the second preset time length.

[0074] It should be noted that the first preset time length is obtained by taking the square root of the product of the parasitic capacitance and the inductance of the fourth switch tube Q4, and the second preset time length is obtained by taking the square root of the product of the parasitic capacitance and the inductance of the third switch tube Q3.

[0075] like Figure 3 As shown, Figure 3 yes Figure 2 Specific flow chart of step S200, step S200 includes but is not limited to steps S210 to S220.

[0076] Step S210, determining a first moment according to the moment when the AC voltage passes through zero from the negative half cycle to the positive half cycle;

[0077] Step S220, starting from the first moment, controlling the second switch tube Q2 to turn on for a first preset time period.

[0078] In some embodiments, when the AC voltage passes through zero from the negative half cycle to the positive half cycle, a first moment is determined according to the moment when the AC voltage passes through zero from the negative half cycle to the positive half cycle. Starting from the first moment, the second switch tube Q2 is controlled to open for a first preset time length so that the electric energy of the parasitic capacitance of the fourth switch tube Q4 can be released into the inductance and capacitance of the power factor correction circuit, thereby avoiding the impact of the electric energy release of the parasitic capacitance of the fourth switch tube Q4 on the circuit and improving the reliability of the circuit.

[0079] It should be noted that when the AC voltage passes through zero from the negative half cycle to the positive half cycle, the inductor is continuously switched on and off by the second switch tube Q2 to store energy and the capacitor is charged by the inductor. Since the fourth switch tube Q4 is in the on state, the voltage of the third switch tube Q3 will be the same as the bus voltage during the process of charging the inductor to the next stage. Therefore, when the neutral line and the live line are switched, the fourth switch tube Q4 needs to be turned off, and the third switch tube Q3 needs to be turned on to prepare for the subsequent low-frequency rectification. Since turning on the third switch tube Q3 immediately at this time will cause energy waste and current shock, it is necessary to release the charge at both ends of the third switch tube Q3.

[0080] like Figure 4 As shown, Figure 4 yes Figure 2 Specific flow chart of step S300, step S300 includes but is not limited to steps S310 to S320.

[0081] Step S310, determining a second time point according to the time point when the AC voltage passes through zero from the positive half cycle to the negative half cycle;

[0082] Step S320, starting from the second moment, controlling the first switch tube Q1 to turn on for a second preset time period.

[0083] In some embodiments, when the AC voltage passes through zero from the positive half cycle to the negative half cycle, a second moment is determined according to the moment when the AC voltage passes through zero from the positive half cycle to the negative half cycle. Starting from the second moment, the first switch tube Q1 is controlled to open for a second preset time length so that the electric energy of the parasitic capacitance of the third switch tube Q3 can be released into the inductance and capacitance of the power factor correction circuit, thereby avoiding the impact of the electric energy release of the parasitic capacitance of the third switch tube Q3 on the circuit and improving the reliability of the circuit.

[0084] In some embodiments, the first moment is the moment when the AC voltage passes through zero from the negative half cycle to the positive half cycle, or the third moment before the AC voltage passes through zero from the negative half cycle to the positive half cycle; the second moment is the moment when the AC voltage passes through zero from the positive half cycle to the negative half cycle, or the fourth moment before the AC voltage passes through zero from the positive half cycle to the negative half cycle, so that the inductor can be charged or discharged in advance, the circuit efficiency is improved, and the current shock caused by the third switch tube Q3 or the fourth switch tube Q4 is avoided.

[0085] like Figure 5 As shown, Figure 5 yes Figure 2 Another specific flow chart of step S200, step S200 includes but is not limited to steps S230 to S240.

[0086] Step S230, monitoring the voltage value of the AC voltage in the negative half cycle of the AC voltage;

[0087] Step S240: when the voltage value of the AC voltage is lower than the first preset voltage value, the second switch tube Q2 is controlled to be turned on for a first preset time period.

[0088] In some embodiments, in the negative half cycle of the AC voltage, the voltage value of the AC voltage is monitored to obtain the voltage size of the AC voltage in the negative half cycle, and then the voltage value of the AC voltage is compared with a first preset voltage value. When the voltage value of the AC voltage is lower than the first preset voltage value, it means that the inductor of the power factor correction circuit can be charged or discharged at this time, and the second switch tube Q2 is controlled to open for a first preset time length so that the electric energy of the parasitic capacitance of the fourth switch tube Q4 can be released into the inductor and capacitor of the power factor correction circuit, thereby improving the circuit efficiency.

[0089] It should be noted that the first preset voltage value is a manually set voltage value, which can be set according to the needs of the user, for example, 0V, 3V, 5V, etc., and this embodiment does not impose any specific limitation.

[0090] It is worth noting that when the voltage value of the AC voltage is higher than the first preset voltage value, there is no need to control the second switch tube Q2 to be turned on, and the second switch tube Q2 can be kept turned off.

[0091] like Figure 6 As shown, Figure 6 yes Figure 2 Another specific flow chart of step S300, step S300 includes but is not limited to steps S330 to S340.

[0092] Step S330, monitoring the voltage value of the AC voltage in the positive half cycle of the AC voltage;

[0093] Step S340: when the voltage value of the AC voltage is lower than the second preset voltage value, the first switch tube Q1 is controlled to be turned on for a second preset time period.

[0094] In some embodiments, in the positive half cycle of the AC voltage, the voltage value of the AC voltage is monitored to obtain the voltage value of the AC voltage in the positive half cycle, and then the voltage value of the positive half cycle is compared with the second preset voltage value. When the voltage value of the AC voltage is lower than the second preset voltage value, it means that the inductor of the power factor correction circuit can be charged or discharged at this time, and the first switch tube Q1 is controlled to open for the second preset time length so that the electric energy of the parasitic capacitance of the third switch tube Q3 can be released into the inductor and capacitor of the power factor correction circuit, thereby improving the circuit efficiency.

[0095] It should be noted that the second preset voltage value is a manually set voltage value and can be set according to the needs of the user, for example, 0V, 3V, 5V, etc., and this embodiment does not impose any specific limitation.

[0096] It is worth noting that when the voltage value of the AC voltage is higher than the second preset voltage value, there is no need to control the first switch tube Q1 to be turned on, and the first switch tube Q1 can be kept turned off.

[0097] like Figure 7 As shown, Figure 7 yes Figure 2 Another specific flow chart of step S200, step S200 includes but is not limited to step S250.

[0098] Step S250, controlling the second switch tube Q2 to turn on by a first conduction pulse, the duration of the first conduction pulse is a first preset duration, or controlling the second switch tube Q2 to turn on by multiple first conduction pulses, the total duration of the multiple first conduction pulses is the first preset duration.

[0099] In some embodiments, in addition to the two situations of controlling the second switch tube Q2 to open for the first preset time from the first moment and controlling the second switch tube Q2 to open for the first preset time according to the first preset voltage value, this embodiment can also control the second switch tube Q2 to open by the first conduction pulse, and use the duration of the first conduction pulse as the first preset time, or control the second switch tube Q2 to open by multiple first conduction pulses, and use the total duration of the multiple first conduction pulses as the first preset time, so that the first preset time can be accurately determined, and the second switch tube Q2 can be accurately controlled, thereby improving the reliability of the circuit and reducing circuit losses.

[0100] like Figure 8 As shown, Figure 8 yes Figure 2 Another specific flow chart of step S300, step S300 includes but is not limited to step S350.

[0101] Step S350, controlling the first switch tube Q1 to turn on through a second conduction pulse, the duration of the second conduction pulse is a second preset duration, or controlling the first switch tube Q1 to turn on through multiple second conduction pulses, the total duration of the multiple second conduction pulses is the second preset duration.

[0102] In some embodiments, in addition to controlling the first switch tube Q1 to turn on for the second preset time starting from the second moment, and controlling the first switch tube Q1 to turn on for the second preset time according to the second preset voltage value, this embodiment can also control the first switch tube Q1 to turn on through a second conduction pulse, and set the duration of the second conduction pulse to the second preset time, or control the first switch tube Q1 to turn on through multiple second conduction pulses, and set the total duration of the multiple second conduction pulses to the second preset time, so that the second preset time can be accurately determined, the first switch tube Q1 can be accurately controlled, the circuit reliability can be improved, and the circuit loss can be reduced.

[0103] The control method of the present application is described in detail below through a specific example.

[0104] Example 1:

[0105] Reference Figure 1 The power factor correction circuit shown includes a first bridge arm 100 and a second bridge arm 200 connected in parallel, and the first bridge arm 100 includes a first switch tube Q1 and a second switch tube Q2 connected in series, and the second bridge arm 200 includes a third switch tube Q3 and a fourth switch tube Q4 connected in series, wherein the first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 are all NMOS tubes.

[0106] The power factor correction circuit is a totem pole circuit, which also includes an inductor L1 and a capacitor C1. The middle connection point of the first bridge arm 100 is connected to one phase of the AC voltage through the inductor L1, and the middle connection point of the second bridge arm 200 is connected to the other phase of the AC voltage. The first bridge arm 100, the second bridge arm 200 and the capacitor C1 are connected in parallel.

[0107] It is worth noting that in this example, the first switch tube Q1 and the second switch tube Q2 are switch tubes with faster switching response speeds, so that they can quickly switch the switch state, reduce the conversion time, and reduce the power loss in the process of switching the switch state. The third switch tube Q3 and the fourth switch tube Q4 are switch tubes with slower switching response speeds. The slower response speed makes the switching process of the switch tube more stable and reduces the cost of the switch tube.

[0108] Based on the above power factor correction circuit, an example of the control method of the present application is proposed.

[0109] like Fig. 9 As shown, Fig. 9 It is a method flow chart of a control method provided by an example of the present application, and the control method includes but is not limited to steps S1 to S7.

[0110] Step S1: Perform zero-crossing detection on the power factor correction circuit;

[0111] Step S2: Detect bus voltage;

[0112] It can be understood that in this example, detecting the bus voltage includes detecting the magnitude, direction, etc. of the bus voltage.

[0113] Step S3: Calculate the pulse time by combining the inductance parameter of the inductor and the capacitance parameter of the capacitor in the power factor correction circuit;

[0114] Step S4: determining the voltage phase of the current voltage passing through the change;

[0115] Step S5: when it is determined that the bus voltage passes through zero from the negative half cycle to the positive half cycle, the second switch tube Q2 is controlled to open for a first preset time length;

[0116] Step S6: when it is determined that the bus voltage passes through zero from the positive half cycle to the negative half cycle, the first switch tube Q1 is controlled to be turned on for a second preset time length;

[0117] Step S7: The power factor correction circuit operates normally.

[0118] Through the above control method, a half-bridge with a slow response speed can be equipped with a cheap switch tube with a large parasitic capacitance and a slow switching speed, thereby reducing costs and improving circuit efficiency and reliability to a certain extent.

[0119] In addition, an embodiment of the present application also provides a controller, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the aforementioned control method when executing the computer program.

[0120] An embodiment of the present application further provides an electrical device, including the aforementioned control method, or including the aforementioned controller.

[0121] It should be noted that the electrical equipment provided in this embodiment has the beneficial effects brought about by the control method of the power factor correction circuit as described above, which will not be described in detail in this embodiment.

[0122] The device embodiments described above are merely illustrative, and the units described as separate components may or may not be physically separated, that is, they may be located in one place or distributed on multiple network nodes. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0123] It will be appreciated by those skilled in the art that all or some of the steps and systems in the disclosed method above may be implemented as software, firmware, hardware and appropriate combinations thereof. Some physical components or all physical components may be implemented as software executed by a processor, such as a central processing unit, a digital signal processor or a microprocessor, or may be implemented as hardware, or may be implemented as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer-readable storage medium (or a non-transitory medium) and a communication medium (or a temporary medium). As known to those skilled in the art, the term computer-readable storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules or other data). Computer-readable storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, disk storage or other magnetic storage devices, or any other medium that may be used to store desired information and may be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically embodies computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0124] The above is a specific description of the preferred implementation of the present application, but the present application is not limited to the above-mentioned implementation mode. Technical personnel familiar with the field can also make various equivalent deformations or substitutions without violating the spirit of the present application. These equivalent deformations or substitutions are all included in the scope defined by the claims of the present application.

Claims

1. A control method for a power factor correction circuit, characterized in that: The power factor correction circuit comprises: The first bridge arm comprises a first switch tube and a second switch tube connected in series, wherein the first switch tube is used to switch the switch state multiple times in a positive half cycle of the AC voltage, and the second switch tube is used to switch the switch state multiple times in a negative half cycle of the AC voltage; The second bridge arm comprises a third switch tube and a fourth switch tube connected in series, wherein the third switch tube and the fourth switch tube are used to controllably switch the switch state at the zero-crossing point of the AC voltage; The control method comprises: When the AC voltage passes through zero from the negative half cycle to the positive half cycle, the second switch tube is controlled to be turned on for a first preset time, the third switch tube is controlled to be turned off, and the fourth switch tube is controlled to be turned on; When the AC voltage passes through zero from the positive half cycle to the negative half cycle, the first switch tube is controlled to be turned on for a second preset time length, the fourth switch tube is controlled to be turned off, and the third switch tube is controlled to be turned on.

2. The control method according to claim 1, characterized in that: The first preset time length is determined according to the parasitic capacitance value of the fourth switch tube, and the second preset time length is determined according to the parasitic capacitance value of the third switch tube.

3. The control method according to claim 1, characterized in that: When the AC voltage passes through zero from the negative half cycle to the positive half cycle, controlling the second switch tube to turn on for a first preset time period includes: Determine the first moment according to the moment when the AC voltage passes through zero from the negative half cycle to the positive half cycle; Starting from the first moment, controlling the second switch tube to be turned on for a first preset time length; When the AC voltage passes through zero from the positive half cycle to the negative half cycle, controlling the first switch tube to turn on for a second preset time period includes: Determine the second moment according to the moment when the AC voltage passes through zero from the positive half cycle to the negative half cycle; Starting from the second moment, the first switch tube is controlled to be turned on for a second preset time period.

4. The control method according to claim 3, characterized in that: The first moment is the moment when the AC voltage passes through zero from the negative half cycle to the positive half cycle, or the third moment before the AC voltage passes through zero from the negative half cycle to the positive half cycle; the second moment is the moment when the AC voltage passes through zero from the positive half cycle to the negative half cycle, or the fourth moment before the AC voltage passes through zero from the positive half cycle to the negative half cycle.

5. The control method according to claim 1, characterized in that: When the AC voltage passes through zero from the negative half cycle to the positive half cycle, controlling the second switch tube to turn on for a first preset time period includes: In the negative half cycle of the AC voltage, the voltage value of the AC voltage is monitored; When the voltage value of the AC voltage is lower than the first preset voltage value, controlling the second switch tube to open for a first preset time length; When the AC voltage passes through zero from the positive half cycle to the negative half cycle, controlling the first switch tube to turn on for a second preset time period includes: In the positive half cycle of the AC voltage, the voltage value of the AC voltage is monitored; When the voltage value of the AC voltage is lower than the second preset voltage value, the first switch tube is controlled to be turned on for a second preset time period.

6. The control method according to claim 1, characterized in that: The controlling the second switch tube to turn on for a first preset time period includes: The second switch tube is controlled to be turned on by a first conduction pulse, the duration of the first conduction pulse is a first preset duration, or the second switch tube is controlled to be turned on by multiple first conduction pulses, the total duration of the multiple first conduction pulses is the first preset duration; The controlling the first switch tube to turn on for a second preset time period includes: The first switch tube is controlled to turn on by a second conduction pulse, the duration of the second conduction pulse is a second preset duration, or the first switch tube is controlled to turn on by multiple second conduction pulses, the total duration of the multiple second conduction pulses is the second preset duration.

7. The control method according to claim 1, characterized in that: The power factor correction circuit is a totem pole circuit, which includes an inductor. The middle connection point of the first bridge arm is connected to one phase of the AC voltage through the inductor, and the middle connection point of the second bridge arm is connected to the other phase of the AC voltage.

8. The control method according to claim 7, characterized in that: The totem pole circuit also includes a capacitor, and the first bridge arm, the second bridge arm and the capacitor are connected in parallel.

9. A controller, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the control method according to any one of claims 1 to 8 when executing the computer program.

10. An electrical device, characterized in that: Comprising a controller as claimed in claim 9.

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