Switching circuit, converter, switching method and electrical equipment of PFC converter

Abstract

The present invention relates to the technical field of AC-DC-AC frequency conversion, and in particular to a switching circuit, a converter, a switching method and an electrical device of a PFC converter. In a normal state, a controller can control a third switch tube to be closed, and a first switch tube, a second switch tube and a fourth switch tube to be disconnected, so as to form a bridged PFC interleaving circuit; when a target rectifier branch of a rectifier unit is in a fault state, the controller can control the third switch tube to be disconnected, and the fourth switch tube and a first switch tube or a second switch tube connected to the same power interface as the input end of the target rectifier branch to be closed, so as to form a bridgeless PFC interleaving circuit, so that the electrical device can operate normally and is convenient for users.

Description

Technical Field

[0001] The present invention relates to the technical field of AC-DC-AC frequency conversion, and in particular to a switching circuit, a converter, a switching method and an electrical device of a PFC converter. Background Art

[0002] Generally, the AC-DC-AC frequency conversion technology is used to drive the inverter in electrical equipment. That is, by inputting AC power, it is converted into DC power through a rectifier, and then the rectified DC power is filtered by a capacitor or a reactor, and finally an inverter is used to exchange the constant DC power into AC power with adjustable voltage and adjustable frequency, so that the DC bus voltage is close to the voltage of the above DC power. The DC bus voltage can be provided to the intelligent power module (Intelligent Power Module, IPM) of the fan and the IPM of the compressor, etc., to achieve coordinated control of the fan, compressor and valve body, and buffer reactive power.

[0003] The above AC-DC-AC conversion can be achieved through a power factor correction (PFC) converter. The traditional PFC converter has the advantages of high reliability, low cost, simple structure and low common-mode interference. However, in actual application, the rectifier bridge diode in the PFC converter is at risk of breakdown. Once the rectifier bridge fails, the electrical equipment cannot operate normally until the damaged diode is replaced, which brings inconvenience to the user. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a switching circuit, converter, switching method and electrical equipment of a PFC converter, so as to overcome the problem that once a rectifier bridge fails, the electrical equipment cannot operate normally until the damaged diode is replaced, which brings inconvenience to the user.

[0005] To achieve the above objectives, the present invention adopts the following technical solutions:

[0006] In one aspect, the present invention provides a switching circuit of a PFC converter, comprising:

[0007] A first circuit and a second circuit are added between two power supply interfaces of the PFC converter and the positive input end of the switch tube unit of the PFC converter; wherein a first switch tube is arranged on the first circuit, and a second switch tube is arranged on the second circuit;

[0008] A third switch tube added to the line between the positive output terminal of the rectifier unit of the PFC converter and the positive input terminal of the switch tube unit;

[0009] A third circuit is added between the positive output end of the rectifier unit of the PFC converter and the positive output end of the switch tube unit, and a fourth switch tube is arranged on the circuit;

[0010] And, a controller connected to the control end of the first switch tube, the control end of the second switch tube, the control end of the third switch tube and the control end of the fourth switch tube respectively.

[0011] Furthermore, the switching circuit of the PFC converter described above further includes a fifth switch tube arranged on at least one switch tube branch in the switch tube unit;

[0012] The control end of the fifth switch tube is connected to the controller.

[0013] Furthermore, in the switching circuit of the PFC converter described above, the first to fifth switch tubes all include power MOSFETs.

[0014] Furthermore, the switching circuit of the PFC converter described above further includes:

[0015] A parameter detector is arranged on each rectifier branch in the rectifier unit, and the parameter detector is connected to the controller.

[0016] On the other hand, the present invention further provides a PFC converter, characterized by comprising a working unit and a switching circuit of the PFC converter described in any one of the above items;

[0017] The working unit is connected to a switching circuit of the PFC converter.

[0018] Furthermore, in the above-mentioned PFC converter, the working unit includes a rectifier unit, a switch tube unit, a filter unit and an inverter unit;

[0019] The two input ends of the rectifier unit are correspondingly connected to two power supply interfaces;

[0020] The positive output terminal of the rectifier unit is connected to the positive input terminal of the switch tube unit, and the positive output terminal of the switch tube unit, the positive terminal of the filter unit and the positive input terminal of the inverter unit are connected;

[0021] The negative output terminal of the rectifier unit is connected to the negative terminal of the switch tube unit, the negative terminal of the filter unit and the negative input terminal of the inverter unit;

[0022] The output end of the inverter unit is used to connect a load.

[0023] Furthermore, in the above-mentioned PFC converter, the switch tube unit includes:

[0024] At least one switch branch;

[0025] Among them, each of the switch tube branches includes an inductor, a sixth switch tube and a seventh switch tube; the first end of the inductor serves as the positive input end of the switch tube unit, the second end of the inductor is respectively connected to the first end of the sixth switch tube and the second end of the seventh switch tube, the second end of the sixth switch tube serves as the positive output end of the switch tube unit, and the first end of the seventh switch tube serves as the negative terminal of the switch tube unit.

[0026] Furthermore, in the above-mentioned PFC converter, the switch tube unit includes three parallel switch tube branches.

[0027] On the other hand, the present invention further provides an electrical device, comprising any one of the PFC converters described above.

[0028] Furthermore, the electrical equipment mentioned above includes an air conditioner or a refrigerator.

[0029] On the other hand, the present invention further provides a switching method of a PFC converter, which is applied to any of the above PFC converters, and the method comprises:

[0030] Detecting the working state of the rectifier unit;

[0031] If it is detected that a target rectifier branch of the rectifier unit is in a fault state, the third switch tube is controlled to be disconnected, and the fourth switch tube and a target switch tube connected to the same power interface as the input end of the target rectifier branch are controlled to be closed, so as to form a bridgeless PFC interleaving circuit; wherein the target switch tube is the first switch tube or the second switch tube;

[0032] If it is detected that the rectifier unit is in a normal state, the third switch tube is controlled to be closed, and the first switch tube, the second switch tube and the fourth switch tube are controlled to be disconnected to form a bridge FPC interleaved circuit.

[0033] Furthermore, in the switching method of the PFC converter described above, the PFC converter further includes a fifth switch tube arranged on at least one switch tube branch in the switch tube unit; the method further includes:

[0034] Detecting the input current value of the power interface;

[0035] The number of the fifth switch tubes in the on state is determined according to the input current value.

[0036] The switching circuit, converter, switching method and electrical equipment of a PFC converter of the present invention include: a first circuit and a second circuit added between two power interfaces of the PFC converter and the positive input end of a switch tube unit of the PFC converter, wherein a first switch tube is arranged on the first circuit and a second switch tube is arranged on the second circuit; a third switch tube is added on the circuit between the positive output end of a rectifier unit of the PFC converter and the positive input end of the switch tube unit; a third circuit is added between the positive output end of the rectifier unit of the PFC converter and the positive output end of the switch tube unit, and a fourth switch tube is arranged on the circuit; and a controller respectively connected to the control end of the first switch tube, the control end of the second switch tube, the control end of the third switch tube and the control end of the fourth switch tube. By adopting the technical solution of the present invention, under normal conditions, the controller can control the third switch tube to close, and the first switch tube, the second switch tube and the fourth switch tube to be disconnected, so as to form a bridged FPC interleaving circuit; when a target rectifier branch of the rectifier unit is in a fault state, the controller can control the third switch tube to be disconnected, and the fourth switch tube and the first switch tube or the second switch tube connected to the same power interface as the input end of the target rectifier branch to be closed, so as to form a bridgeless PFC interleaving circuit, so that the electrical equipment can operate normally and is convenient for users to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 It is a circuit block diagram provided by an embodiment of a switching circuit of a PFC converter of the present invention;

[0039] Figure 2 It is a circuit diagram provided by an embodiment of a PFC converter of the present invention;

[0040] Figure 3 It is a flow chart provided by an embodiment of a switching method of a PFC converter of the present invention. DETAILED DESCRIPTION

[0041] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0042] The switching circuit of the PFC converter of this embodiment is applied in the PFC converter and can switch the working state of the PFC converter. Figure 1 The circuit block diagram is provided by an embodiment of the switching circuit of the PFC converter of the present invention.

[0043] like Figure 1 As shown, the switching circuit of the PFC converter of this embodiment includes: a first circuit and a second circuit added between the two power interfaces of the PFC converter and the positive input end of the switch tube unit of the PFC converter, wherein the first circuit is provided with a first switch tube U1, and the second circuit is provided with a second switch tube U2. That is to say, in the existing PFC converter, there is no connection relationship between the two power interfaces of the PFC converter and the positive input end of the switch tube unit of the PFC converter. In this embodiment, the first circuit and the second circuit are added between the two power interfaces of the PFC converter and the positive input end of the switch tube unit of the PFC converter, and the first switch tube U1 and the second switch tube U2 are correspondingly provided. In this embodiment, the first circuit is added between the first power interface of the PFC converter and the positive input end of the switch tube unit, and the second circuit is added between the second power interface of the PFC converter and the positive input end of the switch tube unit. When the first switch tube U1 is turned on, the first power interface of the PFC converter is connected to the positive input end of the switch tube unit, and when the second switch tube U2 is turned on, the second power interface of the PFC converter is connected to the positive input end of the switch tube unit. In addition, the first power interface and the second power interface are interfaces for connecting to an alternating current power source.

[0044] The switching circuit of the PFC converter of this embodiment further includes: a third switch tube U3 added to the line between the positive output end of the rectifier unit of the PFC converter and the positive input end of the switch tube unit. That is, in the existing PFC converter, there is a connection line between the positive output end of the rectifier unit and the positive input end of the switch tube unit. In this embodiment, the third switch tube U3 is newly added to the connection line. When the third switch tube U3 is turned off, the connection between the positive output end of the rectifier unit and the positive input end of the switch tube unit is disconnected.

[0045] The switching circuit of the PFC converter of this embodiment further includes: a third circuit added between the positive output end of the rectifier unit of the PFC converter and the positive output end of the switch tube unit, and a fourth switch tube U4 is arranged on the circuit. That is, in the existing PFC converter, there is no connection relationship between the positive output end of the rectifier unit of the PFC converter and the positive output end of the switch tube unit. In this embodiment, a third circuit is added between the positive output end of the rectifier unit of the PFC converter and the positive output end of the switch tube unit, and a fourth switch tube U4 is arranged on the third circuit. When the fourth switch tube U4 is turned on, the positive output end of the rectifier unit of the PFC converter is connected to the positive output end of the switch tube unit.

[0046] The switching circuit of the PFC converter of this embodiment further includes: a controller connected to the control end of the first switch tube U1, the control end of the second switch tube U2, the control end of the third switch tube U3 and the control end of the fourth switch tube U4 respectively. The controller controls the first switch tube U1, the second switch tube U2, the third switch tube U3 and the fourth switch tube U4 to be turned on or off respectively by outputting a control signal.

[0047] In the embodiment of the present application, when the rectifier unit of the PFC converter has no abnormality and is in a normal state, the controller can control the third switch tube U3 to close, and the first switch tube U1, the second switch tube U2 and the fourth switch tube U4 to be disconnected, so as to form a bridged FPC interleaving circuit; when there is a target rectifier branch in the rectifier unit that is in a fault state, the controller can control the third switch tube U3 to be disconnected, and the fourth switch tube U4 and the first switch tube U1 or the second switch tube U2 connected to the same power interface as the input end of the target rectifier branch to be closed, so as to form a bridgeless PFC interleaving circuit, so that the electrical equipment can operate normally and is convenient for users to use.

[0048] It should be noted that the rectifier unit of the PFC converter is generally composed of a rectifier bridge. When a diode on a target rectifier branch of the rectifier bridge is damaged, or two diodes on a rectifier branch are damaged at the same time, it means that the target rectifier branch is in a fault state. The probability of one or two diodes being damaged on each rectifier branch is small, and is not considered in the embodiments of the present application.

[0049] In an optional embodiment, the switching circuit of the PFC converter further includes a fifth switch tube U5 disposed on at least one switch tube branch in the switch tube unit, and a control end of the fifth switch tube U5 is connected to the controller. When the fifth switch tube U5 is turned on, the corresponding switch tube branch forms a closed loop and starts to work.

[0050] Specifically, a fifth switch tube U5 may be provided on each switch tube branch of the switch tube unit, or the switch tube branch on which the fifth switch tube U5 needs to be installed may be determined based on actual usage and the number of switch tube branches actually provided, which is not limited in this embodiment. In addition, the user may also determine the number of the fifth switch tubes U5 to be turned on based on actual working conditions to avoid the situation where the load is too large or too small. In an optional embodiment, three switch tube branches may be provided, and the fifth switch tube U5 may be provided on two of the switch tube branches.

[0051] In an optional embodiment, the first switch tube U1 to the fifth switch tube U5 all include power MOSFETs.

[0052] In an optional embodiment, a parameter detector may be further provided on the switching circuit of the PFC converter. Specifically, the parameter detector may be provided on each rectifier branch in the rectifier unit to detect the current or voltage parameters of the branch, and then determine whether the rectifier branch has a fault. The parameter detector is connected to the controller. When the parameter detector detects that the corresponding rectifier branch has a fault, a fault signal may be sent to the controller. The controller may control the first switch tube U1 to the fifth switch tube U5 to switch from a bridge FPC interleaved circuit to a bridgeless PFC interleaved circuit, so that the electrical equipment can operate normally and is convenient for users. The parameter detector may be a voltage sensor or a current sensor, etc., which is not limited in this embodiment.

[0053] In an optional embodiment, an output device, such as an indicator light or a buzzer, may be provided and connected to the controller. When a rectifier branch fails, the controller may control the output device to output a fault signal to inform the user to perform timely maintenance. For example, if an indicator light is used as an output device, a green light may be turned on when one of the rectifier branches fails, a blue light may be turned on when another rectifier branch fails, and a red light may be turned on when both rectifier branches fail.

[0054] Based on a general inventive concept, the present application also provides a PFC converter. Figure 2 : is a circuit diagram provided by an embodiment of a PFC converter of the present invention, such as Figure 2 As shown, the PFC converter of this embodiment includes a working unit and the switching circuit 12 of the PFC converter of the above embodiment, and the working unit and the switching circuit 12 of the PFC converter are connected.

[0055] In an optional embodiment, the working unit includes a rectifier unit 111, a switch tube unit 112, a filter unit 114 and an inverter unit 113. The two input terminals of the rectifier unit 111 are connected to two power supply interfaces respectively, the positive output terminal of the rectifier unit 111 is connected to the positive input terminal of the switch tube unit 112, the positive output terminal of the switch tube unit 112, the positive terminal of the filter unit 114 and the positive input terminal of the inverter unit 113 are connected, the negative output terminal of the rectifier unit 111 is connected to the negative terminal of the switch tube unit 112, the negative terminal of the filter unit 114 and the negative input terminal of the inverter unit 113, and the output terminal of the inverter unit 113 is used to connect the load.

[0056] The power interface includes a first power interface 115 and a second power interface 116. In this embodiment, the first power interface 115 is connected to the first input end of the rectifier unit 111, and the second power interface 116 is connected to the second input end of the rectifier unit 111. The rectifier unit 111 is a rectifier bridge composed of two rectifier branches. The rectifier bridge includes a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4.

[0057] The positive output terminal of the rectifier unit 111 is connected to the positive input terminal of the switch tube unit 112, wherein a third switch tube U3 is provided on the pipeline between the positive output terminal of the rectifier unit 111 and the positive input terminal of the switch tube unit 112. The negative output terminal of the rectifier unit 111 is connected to the negative terminal of the switch tube unit 112. The first power interface 115 is also connected to the positive input terminal of the switch tube unit 112 through the first switch tube U1, and the second power interface 116 is also connected to the positive input terminal of the switch tube unit 112 through the second switch tube U2. Figure 2 shown.

[0058] The positive output terminal of the switch tube unit 112, the positive terminal of the filter unit 114 and the positive input terminal of the inverter unit 113 are connected, and the negative terminal of the switch tube unit 112, the negative terminal of the filter unit 114 and the negative input terminal of the inverter unit 113 are connected. The positive output terminal of the rectifier unit 111 is connected to the positive output terminal of the switch tube unit 112 through the fourth switch tube U4. Figure 2 shown.

[0059] In an optional embodiment, if Figure 2As shown, the switch tube unit 112 includes at least one switch tube branch 1121. Each switch tube branch 1121 includes an inductor L, a sixth switch tube U6, and a seventh switch tube U7. The first end of the inductor L serves as the positive input end of the switch tube unit 112, the second end of the inductor L is respectively connected to the first end of the sixth switch tube U6 and the second end of the seventh switch tube U7, the second end of the sixth switch tube U6 serves as the positive output end of the switch tube unit 112, and the first end of the seventh switch tube U7 serves as the negative terminal of the switch tube unit 112.

[0060] The sixth switch tube U6 and the seventh switch tube U7 both include power MOSFETs. The control terminals of the sixth switch tube U6 and the seventh switch tube U7 may also be connected to the controller, and switch between the on and off states under the control of the controller.

[0061] In an optional embodiment, if Figure 2 As shown, the switch tube unit 112 includes three parallel switch tube branches. The circuit structure of each switch tube branch is basically the same, and all include an inductor L, a sixth switch tube U6, and a seventh switch tube U7. The difference is that in this embodiment, a fifth switch tube U5 is provided on two of the switch tube branches. For the sake of convenience, the inductor and switch tubes in one switch tube branch are defined as a first inductor L1, a sixth switch tube U6, and a seventh switch tube U7, the inductor and switch tubes in another switch tube branch are defined as a second inductor L1, an eighth switch tube U8, and a ninth switch tube U9, and the inductor and switch tubes in another switch tube branch are defined as a third inductor L3, a tenth switch tube U10, and an eleventh switch tube U11. As shown Figure 2 shown.

[0062] In an optional embodiment, if Figure 2 As shown, the filter unit 114 includes a first capacitor C1, a second capacitor C2 and a third capacitor C3. The specifications and models of the first capacitor C1, the second capacitor C2 and the third capacitor C3 can be selected according to actual conditions. For example, the first capacitor C1, the second capacitor C2 and the third capacitor C3 can all be selected to have a specification of 1000 μF.

[0063] In an optional embodiment, if Figure 2 As shown, the inverter unit 113 includes twelfth switch tubes U12 to seventeenth switch tubes U17. The output end of the inverter unit 113 is used to connect to a load Z. The load Z may be a compressor or a fan IPM, which is not limited in this embodiment.

[0064] This application uses a specific embodiment to illustrate the working state of the PFC converter.

[0065] The power interface inputs an AC voltage of 220V. When the input current is less than 10A, only one switch tube branch is in the working state, that is, the fifth switch tubes U5 on the other two branches are in the cut-off state. There are the following working modes:

[0066] First, the seventh switch tube U7 is turned on, and the other switch tubes are turned off. In the positive half cycle of the power interface input voltage 220V, the pin corresponding to the second power interface 116 is positive, and the pin corresponding to the first power interface 115 is negative. The first inductor L1 is charged through the first diode D1, and the first capacitor C1, the second capacitor C2, and the third capacitor C3 provide the inverter unit 113 with positive DC power at the top and negative DC power at the bottom to drive the load Z to work.

[0067] Second, the seventh switch tube U7 is turned off, and the other switch tubes are turned off. The positive half cycle of the power interface input voltage 220V, plus the charging energy of the first inductor L1, passes through the body diode of the sixth switch tube U6, and is charged through the first capacitor C1, the second capacitor C2 and the third capacitor C3 to drive the load Z to work.

[0068] Third, the sixth switch tube U6 is turned on, and the other switch tubes are turned off. In the negative half cycle of the power interface input voltage 220V, the pin corresponding to the second power interface 116 is negative, and the pin corresponding to the first power interface 115 is positive. The first inductor L1 is charged through the second diode D2; the first capacitor C1, the second capacitor C2 and the third capacitor C3 provide the inverter unit 113 with positive DC power at the top and negative at the bottom to drive the load Z to work.

[0069] Fourth, the sixth switch tube U6 is disconnected, and the other switch tubes are cut off. The negative half cycle of the power interface input voltage 220V plus the charging energy of the first inductor L1 passes through the body diode of the seventh switch tube U7 and is charged through the first capacitor C1, the second capacitor C2 and the third capacitor C3.

[0070] The power interface inputs an AC voltage of 220V. When the input current is greater than 10A and less than 20A, two switch tube branches need to be in working state, that is, the fifth switch tube U5 on one of the branches is in the cut-off state. There are the following working modes:

[0071] First, the seventh switch tube U7 and the ninth switch tube U9 are turned on, and the other switch tubes are turned off. The power interface input voltage is 220V in the positive half cycle, the pin corresponding to the second power interface 116 is positive, and the pin corresponding to the first power interface 115 is negative. The first inductor L1 and the second inductor L2 are charged through the first diode D1, and the first capacitor C1, the second capacitor C2 and the third capacitor C3 provide the inverter unit 113 with positive DC power at the top and negative power at the bottom to drive the load Z to work.

[0072] Second, the seventh switch tube U7 and the ninth switch tube U9 are turned off, and the other switch tubes are turned off. The power interface input voltage is 220V in the positive half cycle, plus the charging energy of the first inductor L1 and the second inductor L2, which passes through the body diodes of the sixth switch tube U6 and the eighth switch tube U8, passes through the first diode D1, and is charged through the first capacitor C1, the second capacitor C2 and the third capacitor C3 to drive the load Z to work.

[0073] Third, the sixth switch tube U6 and the eighth switch tube U8 are turned on, and the other switch tubes are turned off. The power interface input voltage is 220V in the negative half cycle, the pin corresponding to the second power interface 116 is negative, and the pin corresponding to the first power interface 115 is positive. The first inductor L1 and the second inductor L2 are charged through the second diode D2, and the first capacitor C1, the second capacitor C2 and the third capacitor C3 provide the inverter unit 113 with positive DC power on the top and negative on the bottom to drive the load Z to work.

[0074] Fourth, the sixth switch tube U6 and the eighth switch tube U8 are turned off, and the other switch tubes are turned off. The power interface input voltage is 220V in the negative half cycle, plus the charging energy of the first inductor L1 and the second inductor L2, which is charged through the body diodes of the seventh switch tube U7 and the ninth switch tube U9, through the first capacitor C1, the second capacitor C2 and the third capacitor C3, and drives the load Z to work.

[0075] The power interface inputs an AC voltage of 220V. When the input current is greater than 20A and less than 30A, three switch tube branches need to be in working state, that is, the fifth switch tubes U5 on both branches are in the on state. There are the following working modes:

[0076] First, the seventh switch tube U7, the ninth switch tube U9 and the eleventh switch tube 11 are turned on, and the other switch tubes are turned off. The power interface input voltage is 220V in the positive half cycle, the pin corresponding to the second power interface 116 is positive, and the pin corresponding to the first power interface 115 is negative. The first inductor L1, the second inductor L2 and the third inductor L3 are charged through the first diode D1, and the first capacitor C1, the second capacitor C2 and the third capacitor C3 provide the inverter unit 113 with positive DC power at the top and negative at the bottom to drive the load Z to work.

[0077] The second and seventh switch tubes U7, the ninth switch tube U9 and the eleventh switch tube 11 are turned off, and the other switch tubes are turned off. The power interface input voltage 220V in the positive half cycle, plus the charging energy of the first inductor L1, the second inductor L2 and the third inductor L3, passes through the body diodes of the sixth switch tube U6, the eighth switch tube U8 and the tenth switch tube 10, passes through the first diode D1, and is charged through the first capacitor C1, the second capacitor C2 and the third capacitor C3 to drive the load Z to work.

[0078] The third and sixth switch tubes U6, the eighth switch tube U8 and the tenth switch tube 10 are turned on, and the other switch tubes are turned off. The power interface input voltage is 220V in the negative half cycle, the pin corresponding to the second power interface 116 is negative, and the pin corresponding to the first power interface 115 is positive. The first inductor L1, the second inductor L2 and the third inductor L3 are charged through the second diode D2, and the first capacitor C1, the second capacitor C2 and the third capacitor C3 provide the inverter unit 113 with positive DC power at the top and negative at the bottom to drive the load Z to work.

[0079] The fourth and sixth switch tubes U6, the eighth switch tube U8 and the tenth switch tube 10 are turned off, and the other switch tubes are turned off. The power interface input voltage 220V in the negative half cycle, plus the charging energy of the first inductor L1, the second inductor L2 and the third inductor L3, passes through the body diodes of the seventh switch tube U7, the ninth switch tube U9 and the eleventh switch tube 11, and is charged through the first capacitor C1, the second capacitor C2 and the third capacitor C3 to drive the load Z to work.

[0080] Based on a general inventive concept, the present application also provides an electrical device, characterized in that it includes the PFC converter of the above embodiment.

[0081] In an optional embodiment, the electrical appliance includes an air conditioner or a refrigerator.

[0082] Based on a general inventive concept, the present application also provides a switching method for a PFC converter. Figure 3 is a flow chart provided by an embodiment of a switching method of a PFC converter of the present invention, such as Figure 3 As shown, the method of this embodiment may include the following steps:

[0083] S21, detecting the working state of the rectifier unit;

[0084] S22, if it is detected that a target rectifier branch of the rectifier unit is in a fault state, the third switch tube is controlled to be disconnected, and the fourth switch tube and the target switch tube connected to the same power interface as the input end of the target rectifier branch are controlled to be closed, so as to form a bridgeless PFC interleaving circuit; wherein the target switch tube is the first switch tube or the second switch tube;

[0085] S23, if it is detected that the rectifier unit is in a normal state, the third switch tube is controlled to be closed, and the first switch tube, the second switch tube and the fourth switch tube are controlled to be disconnected, so as to form a bridge FPC interleaved circuit.

[0086] It should be noted that the working state of the rectifier unit may be detected by a current or voltage sensor disposed on the rectifier branch, or by other means, which is not limited in this embodiment.

[0087] By adopting the technical solution of this embodiment, under normal conditions, the controller can control the third switch tube to close, and the first switch tube, the second switch tube and the fourth switch tube to be disconnected, so as to form a bridged FPC interleaving circuit; when a target rectifier branch of the rectifier unit is in a fault state, the controller can control the third switch tube to be disconnected, and the fourth switch tube and the first switch tube or the second switch tube connected to the same power interface as the input end of the target rectifier branch to be closed, so as to form a bridgeless PFC interleaving circuit, so that the electrical equipment can operate normally and is convenient for users to use.

[0088] Furthermore, in an optional embodiment, the PFC converter further includes a fifth switch tube disposed on at least one switch tube branch in the switch tube unit. The steps of this embodiment further include:

[0089] Detect the input current value of the power interface;

[0090] The number of the fifth switch tubes in the on state is determined according to the input current value.

[0091] Specifically, the input current value of the power interface can be determined based on the current sensor, and the number of the fifth switch tubes in the on state can be determined according to the input current value. For example, if the current value is small, fewer fifth switch tubes can be controlled to be in the on state, and if the current value is large, more fifth switch tubes can be controlled to be in the on state. The specific current value and the number of the fifth switch tubes that are turned on can be determined according to the actual working state and the specifications of the components on the switch tube branch, and this embodiment will not be repeated.

[0092] It can be understood that the same or similar parts of the above embodiments can be referenced to each other, and the contents not described in detail in some embodiments can refer to the same or similar contents in other embodiments.

[0093] It should be noted that, in the description of the present invention, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, the meaning of "plurality" refers to at least two.

[0094] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present invention belong.

[0095] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0096] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0097] In addition, each functional unit in each embodiment of the present invention may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0098] The storage medium mentioned above can be a read-only memory, a magnetic disk or an optical disk, etc.

[0099] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0100] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A switching circuit for a PFC converter, characterized in that: include: A first circuit and a second circuit are added between two power supply interfaces of the PFC converter and the positive input end of the switch tube unit of the PFC converter; wherein a first switch tube is arranged on the first circuit, and a second switch tube is arranged on the second circuit; A third switch tube added to the line between the positive output end of the rectifier unit of the PFC converter and the positive input end of the switch tube unit; A third circuit is added between the positive output end of the rectifier unit of the PFC converter and the positive output end of the switch tube unit, and a fourth switch tube is arranged on the third circuit; and a controller connected to the control end of the first switch tube, the control end of the second switch tube, the control end of the third switch tube, and the control end of the fourth switch tube respectively; Wherein, the switch tube unit comprises: At least one switch branch; Among them, each of the switch tube branches includes an inductor, a sixth switch tube and a seventh switch tube; the first end of the inductor serves as the positive input end of the switch tube unit, the second end of the inductor is respectively connected to the first end of the sixth switch tube and the second end of the seventh switch tube, the second end of the sixth switch tube serves as the positive output end of the switch tube unit, and the first end of the seventh switch tube serves as the negative terminal of the switch tube unit.

2. The switching circuit of the PFC converter according to claim 1, characterized in that: It also includes a fifth switch tube arranged on at least one switch tube branch in the switch tube unit; The control end of the fifth switch tube is connected to the controller.

3. The switching circuit of the PFC converter according to claim 2, characterized in that: The first to fifth switch tubes all include power MOSFETs.

4. The switching circuit of the PFC converter according to claim 1, characterized in that: Also includes: A parameter detector is arranged on each rectifier branch in the rectifier unit, and the parameter detector is connected to the controller.

5. A PFC converter, characterized in that: A switching circuit comprising a working unit and a PFC converter according to any one of claims 1 to 4; The working unit is connected to a switching circuit of the PFC converter.

6. The PFC converter according to claim 5, characterized in that: The working unit includes a rectifying unit, a switching tube unit, a filtering unit and an inverter unit; The two input ends of the rectifier unit are correspondingly connected to two power supply interfaces; The positive output terminal of the rectifier unit is connected to the positive input terminal of the switch tube unit, and the positive output terminal of the switch tube unit, the positive terminal of the filter unit and the positive input terminal of the inverter unit are connected; The negative output terminal of the rectifier unit is connected to the negative terminal of the switch tube unit, the negative terminal of the filter unit and the negative input terminal of the inverter unit; The output end of the inverter unit is used to connect a load.

7. The PFC converter according to claim 5, characterized in that: The switch tube unit includes three switch tube branches connected in parallel.

8. An electrical device, characterized in that: A PFC converter comprising any one of claims 5 to 7.

9. The electrical device according to claim 8, characterized in that: The electrical equipment includes an air conditioner or a refrigerator.

10. A switching method for a PFC converter, characterized in that: Applied to the PFC converter according to any one of claims 5 to 7, the method comprises: Detecting the working state of the rectifier unit; If it is detected that a target rectifier branch of the rectifier unit is in a fault state, the third switch tube is controlled to be disconnected, and the fourth switch tube and a target switch tube connected to the same power interface as the input end of the target rectifier branch are controlled to be closed, so as to form a bridgeless PFC interleaving circuit; wherein the target switch tube is the first switch tube or the second switch tube; If it is detected that the rectifier unit is in a normal state, the third switch tube is controlled to be closed, and the first switch tube, the second switch tube and the fourth switch tube are controlled to be disconnected to form a bridge FPC interleaved circuit.

11. The switching method of the PFC converter according to claim 10, characterized in that: The PFC converter further includes a fifth switch tube disposed on at least one switch tube branch in the switch tube unit; and the method further includes: Detecting the input current value of the power interface; The number of the fifth switch tubes in the on state is determined according to the input current value.

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