A soft switch totem pole circuit, control method and air conditioner

Abstract

The present application provides a soft switch totem pole circuit, a control method and an air conditioner, and relates to the technical field of totem pole circuits. The totem pole module includes a first switch tube and a second switch tube, and the first switch tube and the second switch tube are both electrically connected to the soft switch module; when the totem pole module works in the positive half cycle, and the first switch tube is turned on and the second switch tube is turned off, the soft switch module forms a parallel circuit with the first switch tube, and forms a series circuit with the parasitic capacitance of the second switch tube, so that the first switch tube is turned off with zero current and the second switch tube is turned on with zero voltage; when the totem pole module works in the negative half cycle, and the second switch tube is turned on and the first switch tube is turned off, the soft switch module forms a parallel circuit with the second switch tube, and forms a series circuit with the parasitic capacitance of the first switch tube, so that the second switch tube is turned off with zero current and the first switch tube is turned on with zero voltage. The present application has the effect of being able to realize the soft switching of two switch tubes through a hardware circuit.

Description

Technical Field

[0001] The present invention relates to the technical field of totem pole circuits, and in particular to a soft switch totem pole circuit, a control method and an air conditioner. Background Art

[0002] The main switch tube in the totem pole circuit mostly works under higher frequency conditions, but the harmonics and current pulse problems caused by its hard switching greatly affect the quality and progress of product development. Therefore, soft switching of the totem pole main switch tube is extremely important.

[0003] At present, the method of realizing soft switching of the totem pole main switch tube is mostly to use software logic control to delay the conduction time to reduce the peak current and harmonic problems, but it also brings about the temperature rise problem of the switch tube; there are also hardware implementation solutions that take into account the reduction of peak current, harmonics and temperature rise, but they cannot realize the soft switching of the upper and lower bridge switch tubes at the same time, and can only act on the lower bridge tube.

[0004] In summary, the prior art cannot realize soft switching of two switch tubes at the same time. Summary of the invention

[0005] The object of the present invention is to provide a soft switching totem pole circuit, a control method and an air conditioner to solve the problem in the prior art that soft switching of two switch tubes cannot be achieved simultaneously.

[0006] To solve the above problems, in a first aspect, an embodiment of the present application provides a soft switching totem pole circuit, wherein the soft switching totem pole circuit comprises a totem pole module and a soft switch module, wherein the totem pole module comprises a first switch tube and a second switch tube, wherein the first switch tube and the second switch tube are both electrically connected to the soft switch module; wherein, when the totem pole module operates in a positive half cycle, and the first switch tube is turned on and the second switch tube is turned off, the soft switch module forms a parallel circuit with the first switch tube, and a series circuit with the second switch tube, so that the first switch tube is turned off at zero current and the second switch tube is turned on at zero voltage; when the totem pole module operates in a negative half cycle, and the second switch tube is turned on and the first switch tube is turned off, the soft switch module forms a parallel circuit with the second switch tube, and a series circuit with the first switch tube, so that the second switch tube is turned off at zero current and the first switch tube is turned on at zero voltage.

[0007] Since the soft switch totem pole circuit provided by the present application adds a soft switch module on the basis of the existing totem pole module, it realizes zero current disconnection of one switch tube and zero voltage conduction of the other switch tube through the hardware circuit, so it can realize soft switching of two switch tubes at the same time. And because it is realized by hardware circuit, it will not cause the temperature rise problem of the switch tube.

[0008] Optionally, the soft switch module includes a first soft switch loop and a second soft switch loop, the first soft switch loop is connected in series with the first switch tube, the second soft switch loop is connected in series with the second switch tube, and the first soft switch loop is electrically connected to the second soft switch loop; wherein,

[0009] When the totem pole module operates in a positive half cycle, and the first switch tube is turned on and the second switch tube is turned off, the first switch tube is connected in parallel with the second soft switch loop, and the second switch tube is connected in series with the second soft switch loop;

[0010] When the totem pole module operates in the negative half cycle, and the second switch tube is turned on and the first switch tube is turned off, the second switch tube is connected in parallel with the first soft switch loop, and the first switch tube is connected in series with the first soft switch loop.

[0011] Optionally, the first soft switching loop includes a third switching tube, a first inductor and a first diode, and the second soft switching loop includes a fourth switching tube, a second inductor and a second diode. The first end of the third switching tube is electrically connected to one end of the first switching tube, the second end of the third switching tube is electrically connected to one end of the first inductor, the other end of the first inductor is respectively electrically connected to one end of the second inductor, the anode of the first diode, and the cathode of the second diode, the cathode of the first diode is electrically connected to the other end of the first switching tube, the anode of the second diode is electrically connected to one end of the second switching tube, the other end of the second inductor is electrically connected to the first end of the fourth switching tube, and the second end of the fourth switching tube is electrically connected to the other end of the second switching tube.

[0012] Optionally, the soft switching module further includes a third diode, an anode of the third diode is electrically connected to the other end of the second inductor, and a cathode of the third diode is electrically connected to one end of the first switch tube.

[0013] Optionally, the soft switch totem pole circuit further includes a control module, and the control module is electrically connected to the control ends of the first switch tube, the second switch tube, the third switch tube and the fourth switch tube respectively; wherein,

[0014] When the totem pole module operates in the positive half cycle and the first switch tube is turned on and the second switch tube is turned on, the control module is used to control the first switch tube to be turned off after a first preset time after the fourth switch is turned on, and control the second switch tube to be turned on after a second preset time;

[0015] When the totem pole module operates in the negative half cycle, and the second switch tube is turned on and the first switch tube is turned on, the control module is used to control the third switch to be turned on, then control the second switch tube to be turned off after a first preset time, and control the first switch tube to be turned on after a second preset time.

[0016] Optionally, the totem pole module also includes a third inductor, a fourth diode, a fifth diode and a capacitor, one end of the third inductor is electrically connected to the live wire of the AC power supply, the other end of the third inductor is respectively connected to the first switch tube and the second switch tube, the neutral line of the AC power supply is respectively electrically connected to the anode of the fourth diode and the cathode of the fifth diode, the cathode of the fourth diode is respectively electrically connected to the first switch tube and one end of the capacitor, and the other end of the capacitor is respectively connected to the anode of the fifth diode and the second switch tube.

[0017] In a second aspect, an embodiment of the present application further provides an air conditioner, which includes the above-mentioned soft switching totem pole circuit.

[0018] In a third aspect, an embodiment of the present application further provides a soft switch totem pole circuit control method, the method is applied to the above-mentioned soft switch totem pole circuit, the method comprising:

[0019] When the totem pole module operates in the positive half cycle, and the first switch tube is turned on and the second switch tube is turned off, the soft switch module is controlled to operate so that the first switch tube is turned off with zero current and the second switch tube is turned on with zero voltage;

[0020] When the totem pole module operates in the negative half cycle, and the second switch tube is disconnected and the first switch tube is turned on, the soft switch module is controlled to operate so that the first switch tube is disconnected with zero current and the second switch tube is turned on with zero voltage.

[0021] Optionally, the soft switch module includes a first soft switch circuit and a second soft switch circuit, the first soft switch circuit is connected in series with the first switch tube, the second soft switch circuit is connected in series with the second switch tube, and the first soft switch circuit is electrically connected to the second soft switch circuit; when the totem pole module works in a positive half cycle, the step of controlling the soft switch module to work includes:

[0022] Controlling the second soft switch loop to be turned on and the first soft switch loop to be turned off;

[0023] After the step of the soft switch module operating, the method further comprises:

[0024] After a first preset time, the first switch tube is controlled to be disconnected, so that the first switch tube is disconnected with zero current;

[0025] After a second preset time, controlling the second switch tube to be turned on, so that the second switch tube is turned on at zero voltage;

[0026] When the totem pole module operates in the negative half cycle, the step of controlling the soft switch module to operate includes:

[0027] Controlling the first soft switch loop to be turned on and the second soft switch loop to be turned off;

[0028] After the step of the soft switch module operating, the method further comprises:

[0029] After a first preset time, controlling the second switch tube to be turned off, so that the second switch tube is turned off with zero current;

[0030] After a second preset time, the first switch tube is controlled to be turned on, so that the first switch tube is turned on at zero voltage.

[0031] Optionally, when the totem pole module operates in a positive half cycle, before the step of controlling the soft switch module to operate, the method further includes:

[0032] Controlling the first switch tube to be turned off, and controlling the second switch tube to be turned on;

[0033] After a preset time, the second switch tube is controlled to be turned on and the first switch tube is turned off;

[0034] When the totem pole module operates in the negative half cycle, before the step of controlling the soft switch module to operate, the method further includes:

[0035] Controlling the second switch tube to be turned off, and controlling the first switch tube to be turned on;

[0036] After a preset time, the first switch tube is controlled to be turned off and the second switch tube is controlled to be turned on. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a circuit diagram of a totem pole circuit in the prior art.

[0038] Figure 2 A module schematic diagram of a soft switching totem pole circuit provided in an embodiment of the present application.

[0039] Figure 3 A circuit diagram of a soft switching totem pole circuit provided in an embodiment of the present application.

[0040] Figure 4 A schematic flow chart of a soft switching totem pole circuit control method provided in an embodiment of the present application.

[0041] Description of reference numerals:

[0042] 100-soft switch totem pole circuit; 110-totem pole module; 120-soft switch module; 121-first soft switch loop; 122-second soft switch loop; Q1-first switch tube; Q2-second switch tube; Q3-third switch tube; Q4-fourth switch tube; D1-first diode; D2-second diode; D3-third diode; D4-fourth diode; D5-fifth diode; L1-first inductor; L2-second inductor; L3-third inductor; E-capacitor. DETAILED DESCRIPTION

[0043] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0044] As described in the background art, the current method of realizing soft switching of the totem pole main switch tube cannot realize soft switching of the upper and lower bridge switch tubes at the same time.

[0045] Among them, the totem pole circuit commonly used in the prior art is as follows Figure 1 As shown, the totem pole topology consists of an input power supply AC_IN, an inductor L, main switch tubes S1 and S2, main switch tube parasitic capacitors C1 and C2, freewheeling diodes D1 and D2, an electrolytic capacitor E and a load R.

[0046] The working principle of the totem pole circuit is:

[0047] When AC_IN is in the positive half cycle, there are two states in the circuit. The first state is numbered ①. At this time, the circuit switch tube S1 is disconnected, the switch tube S2 is closed, and current flows through the L-S2-D2 loop, and the inductor stores energy. The second state is numbered ②. At this time, the circuit switch tube S1 is closed, the switch tube S2 is disconnected, and current flows through the L-S1-E-D2 loop, and the electrolytic capacitor E is charged. In addition, during the positive half cycle of AC_IN, states ① and ② cycle back and forth, that is, it works according to state ① first, and then works according to state ② after a period of time, and then continues to work according to state ① after a period of time, and then works according to state ② again for a period of time, and so on until the negative half cycle of AC_IN arrives.

[0048] When AC_IN is in the negative half cycle, there are also two states in the circuit. The first state is numbered ③. At this time, the circuit switch tube S1 is closed, the switch tube S2 is disconnected, and current flows through the D1-S1-L loop, and the inductor stores energy. The second state is numbered ④. At this time, the circuit switch tube S1 is disconnected, the switch tube S2 is closed, and current flows through the D1-E-S2-L loop, and the electrolytic capacitor E is charged. In addition, during the negative half cycle of AC_IN, states ③ and ④ cycle back and forth, that is, it works according to state ③ first, and then works according to state ④ after a period of time, and then continues to work according to state ③ after a period of time, and then works according to state ④ for a period of time, and works repeatedly until the negative half cycle of AC_IN arrives.

[0049] It can be understood that due to the presence of parasitic capacitors C1 and C2 in the switch tube, when the switch tube is turned on or off, due to the energy storage effect of the parasitic capacitors C1 and C2, the switch tube S1 and the switch tube S2 cannot achieve soft switching. Among them, soft switching means that the current or voltage of the switch tube is zero when it is turned on or off. For example, when in the above-mentioned state ②, although the switch tube S2 is in the off state, due to the presence of the parasitic capacitor C2, the parasitic capacitor C2 will store energy. When it is converted to the state ① again, the switch tube S2 is turned on. At this time, part of the energy has been stored in the parasitic capacitor C2, so the switch tube is turned on for a shorter time, which will have a negative impact on the entire circuit.

[0050] Therefore, it is necessary to implement soft switching of the switch tube in the totem pole circuit. In the prior art, software is generally used to adjust the on-time of the switch tube. For example, for the switch tube S2, due to the energy storage of the parasitic capacitor C2, the on-time of the switch tube S2 is reduced, and it is necessary to adjust it by delaying the on-time. However, the software method will bring about temperature rise and other problems. It is impossible to implement soft switching of two switch tubes at the same time by using other hardware solutions.

[0051] Therefore, according to the problems existing in the prior art, the applicant has added a soft switch module to the soft switch totem pole circuit to achieve soft switching of the two main switch tubes by means of hardware.

[0052] The soft switching totem pole circuit 100 provided in the present application is exemplarily described below:

[0053] As an alternative implementation, see Figure 2 and Figure 3The soft switch totem pole circuit includes a totem pole module 110 and a soft switch module 120. The totem pole module 110 includes a first switch tube Q1 and a second switch tube Q2. Both the first switch tube Q1 and the second switch tube Q2 are electrically connected to the soft switch module 120. When the totem pole module 110 works in a positive half cycle, and the first switch tube Q1 is turned on and the second switch tube Q2 is turned off, the soft switch module 120 forms a parallel circuit with the first switch tube Q1, and forms a series circuit with the parasitic capacitance of the second switch tube Q2, so that the first switch tube Q1 is turned off with zero current and the second switch tube Q2 is turned on with zero voltage; when the totem pole module 110 works in a negative half cycle, and the second switch tube Q2 is turned on and the first switch tube Q1 is turned off, the soft switch module forms a parallel circuit with the second switch tube Q2, and forms a series circuit with the parasitic capacitance of the first switch tube Q1, so that the second switch tube Q2 is turned off with zero current and the first switch tube Q1 is turned on with zero voltage.

[0054] That is, no matter the totem pole module 110 works in the positive half cycle or the negative half cycle, the soft switching of the first switch tube Q1 and the second switch tube Q2 can be achieved, and since the present application is implemented in hardware, it will not cause temperature rise problems.

[0055] It should be noted that the switch tube described in the present application can be a triode or a MOS tube, which is not limited here.

[0056] Optionally, the totem pole module 110 provided in the present application also includes a third inductor L3, a fourth diode D4, a fifth diode D5 and a capacitor E, one end of the third inductor L3 is electrically connected to the live wire of the AC power supply, the other end of the third inductor L3 is respectively connected to the first switch tube Q1 and the second switch tube Q2, the neutral line of the AC power supply is respectively electrically connected to the anode of the fourth diode D4 and the cathode of the fifth diode D5, the cathode of the fourth diode D4 is respectively electrically connected to the first switch tube Q1 and one end of the capacitor E, and the other end of the capacitor E is respectively connected to the anode of the fifth diode D5 and the second switch tube Q2.

[0057] The totem pole module 110 is the same as the existing totem pole circuit, and its working principle will not be described in detail here.

[0058] As an implementation method, the soft switch module 120 includes a first soft switch circuit 121 and a second soft switch circuit 122, the first soft switch circuit 121 is connected in series with the first switch tube Q1, the second soft switch circuit is connected in series with the second switch tube Q2, and the first soft switch circuit 121 is electrically connected to the second soft switch circuit 122; wherein, when the totem pole module 110 operates in a positive half cycle, and the first switch tube Q1 is turned on, and the second switch tube Q2 is turned off, the first switch tube Q1 is connected in parallel with the second soft switch circuit 122, and the parasitic capacitance of the second switch tube Q2 is connected in series with the second soft switch circuit 122; when the totem pole module 110 operates in a negative half cycle, and the second switch tube Q2 is turned on, and the first switch tube Q1 is turned off, the second switch tube Q2 is connected in parallel with the first soft switch circuit 121, and the parasitic capacitance of the first switch tube Q1 is connected in series with the first soft switch circuit 121.

[0059] Optionally, the first soft switching loop 121 includes a third switching tube Q3, a first inductor L1 and a first diode D1, and the second soft switching loop 122 includes a fourth switching tube Q4, a second inductor L2 and a second diode D2. The first end of the third switching tube Q3 is electrically connected to one end of the first switching tube Q1, the second end of the third switching tube Q3 is electrically connected to one end of the first inductor L1, the other end of the first inductor L1 is respectively electrically connected to one end of the second inductor L2, the anode of the first diode D1, and the cathode of the second diode D2, the cathode of the first diode D1 is electrically connected to the other end of the first switching tube Q1, the anode of the second diode D2 is electrically connected to one end of the second switching tube Q2, the other end of the second inductor L2 is electrically connected to the first end of the fourth switching tube Q4, and the second end of the fourth switching tube Q4 is electrically connected to the other end of the second switching tube.

[0060] In addition, the soft switching totem pole circuit 100 also includes a control module, which is electrically connected to the control ends of the first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 respectively; wherein, when the totem pole module 110 operates in the positive half cycle, and the first switch tube Q1 is turned on and the second switch tube Q2 is turned off, the control module is used to control the first switch tube Q1 to be turned off after a first preset time after the fourth switch is turned on, and to control the second switch tube Q2 to be turned on after a second preset time; when the totem pole module 110 operates in the negative half cycle, and the second switch tube Q2 is turned on and the first switch tube Q1 is turned off, the control module is used to control the second switch tube Q2 to be turned off after a first preset time after the third switch is turned on, and to control the first switch tube Q1 to be turned on after the second preset time.

[0061] The working principle of the soft switching totem pole circuit 100 provided in this application is:

[0062] When the totem pole module 110 works in the positive half cycle of AC_IN, the above states ① and ② cycle back and forth. When in state ②, the fourth switch tube Q4 is turned on, and the current of the loop in the third inductor L3 will be shunted by the first switch tube Q1 branch (the branch composed of the first switch tube Q1, capacitor E, and second diode D2) and the fourth switch tube Q4 branch (the branch composed of the fifth diode D5, the second inductor L2, and the fourth switch tube Q4), but due to the inductance energy storage effect of the second inductor L2, the current on the first switch tube Q1 branch gradually decreases to 0, and then the first switch tube Q1 is disconnected (i.e., zero current disconnection is achieved); the second inductor L2, the fourth switch tube Q4, the parasitic capacitor C2, and the freewheeling tube D4 form a resonant circuit, release the energy on the inductor and the parasitic capacitor C2 to 0, and then close the second switch tube Q2 (i.e., zero voltage conduction is achieved), and the fourth switch tube Q4 is disconnected at the same time, entering state ①.

[0063] When the totem pole module 110 works in the negative half cycle of AC_IN, the above states ③ and ④ cycle back and forth. When in state ④, the third switch tube Q3 is turned on, and the current of the third inductor L3 loop will be shunted by the second switch tube Q2 and the third switch tube Q3. However, due to the inductance energy storage effect of the first inductor L1, the current on the second switch tube Q2 branch gradually decreases to 0, and then the second switch tube Q2 is disconnected (i.e., zero current disconnection is achieved); the first inductor L1, the third switch tube Q3, the parasitic capacitor C1, and the freewheeling tube D3 form a resonant circuit, release the energy on the inductor and capacitor C1 to 0, and then close the first switch tube Q1 (i.e., zero voltage conduction is achieved) and disconnect the third switch tube Q3 at the same time, entering state ③.

[0064] It should be noted that there is a certain sequence in the execution process, that is, zero current disconnection is required first, and then zero voltage conduction is performed. For example, when the totem pole module 110 is in state ②, after the fourth switch tube Q4 is controlled to be turned on, the current of the first switch tube Q1 will drop to 0, at this time, the first diode D1 is disconnected, the second inductor L2, the fourth switch tube Q4, the parasitic capacitor E, and the freewheeling tube D4 form a resonant circuit, and the LC resonant circuit is discharged, thereby discharging the electricity of the capacitor E.

[0065] On this basis, in order to ensure that the electricity in the second inductor L2 is completely discharged, the module also includes a third diode D3, the anode of the third diode D3 is electrically connected to the other end of the second inductor L2, and the cathode of the third diode D3 is electrically connected to one end of the first switch tube Q1.

[0066] This connection ensures that the electric energy of the second inductor L2 is fully released. For example, when the totem pole module 110 works in the positive half cycle, the second switch tube Q2 is already turned on, and the fourth switch tube Q4 is turned off. Then the second inductor L2, the third switch tube Q3, the parasitic capacitor E, and the freewheeling tube D4 no longer form a resonant circuit, and the second inductor L2 forms a discharge circuit with the third diode D3 and the capacitor E to fully release the electric energy in the second inductor L2. When the totem pole module 110 works in the negative half cycle, and the first switch tube Q1 is already turned on, the third switch tube Q3 is turned off, and the first inductor L1, the second inductor L2, the third diode D3 and the capacitor E form a discharge circuit, and the first inductor L1 is discharged through the second inductor L2 and the third diode D3.

[0067] Based on the above implementation, the present application also provides an air conditioner, which includes the above soft switching totem pole circuit 100.

[0068] See also Figure 4 The embodiment of the present application further provides a soft switch totem pole circuit control method, which is applied to the above-mentioned soft switch totem pole circuit 100, and the method includes:

[0069] S102, when the totem pole module operates in the positive half cycle, and the first switch tube is turned on and the second switch tube is turned off, the soft switch module is controlled to operate so that the first switch tube is turned off with zero current and the second switch tube is turned on with zero voltage.

[0070] S104, when the totem pole module operates in the negative half cycle, and the second switch tube is turned on and the first switch tube is turned off, the soft switch module is controlled to operate so that the second switch tube is turned off with zero current and the first switch tube is turned on with zero voltage.

[0071] Among them, either S102 or S104 is executed.

[0072] As an implementation, the soft switch module 120 includes a first soft switch circuit 121 and a second soft switch circuit 122, the first soft switch circuit 121 is connected in series with the first switch tube Q1, the second soft switch circuit is connected in series with the second switch tube Q2, and the first soft switch circuit 121 is electrically connected to the second soft switch circuit 122; when the totem pole module 110 works in the positive half cycle, the steps of controlling the soft switch module 120 to work include:

[0073] S1021, controlling the second soft switch loop 122 to be turned on and the first soft switch loop 121 to be turned off.

[0074] After the step of the soft switch module 120 working, the method further includes:

[0075] S1022, controlling the first switch tube Q1 to be turned off after a first preset time, so that the first switch tube Q1 is turned off with zero current.

[0076] S1023, controlling the second switch tube Q2 to be turned on after a second preset time, so that the second switch tube Q2 is turned on with zero voltage.

[0077] When the totem pole module operates in the negative half cycle, the steps of controlling the soft switch module 120 to operate include:

[0078] S1041, controlling the first soft switch loop 121 to be turned on and the second soft switch loop 122 to be turned off.

[0079] After the step of the soft switch module working, the method further comprises:

[0080] S1042, controlling the second switch tube Q2 to be turned off after a first preset time, so that the second switch tube Q2 is turned off with zero current.

[0081] S1043, controlling the first switch tube Q1 to turn on after a second preset time, so that the first switch tube Q1 is turned on with zero voltage.

[0082] Optionally, when the totem pole module operates in the positive half cycle, before the step of controlling the soft switch module 120 to operate, the method further includes:

[0083] S1011, controlling the first switch tube Q1 to be turned off, and controlling the second switch tube Q2 to be turned on.

[0084] S1012, after a preset time, the second switch tube Q2 is controlled to be turned off, and the first switch tube Q1 is controlled to be turned on.

[0085] When the totem pole module operates in the negative half cycle, before the step of controlling the soft switch module 120 to operate, the method further includes:

[0086] S1031, controlling the second switch tube to be turned off, and controlling the first switch tube to be turned on.

[0087] S1032, after a preset time, control the first switch tube to be turned off and the second switch tube to be turned on.

[0088] In summary, the embodiment of the present application provides a soft switching totem pole circuit, wherein the soft switching totem pole circuit includes a totem pole module and a soft switch module, wherein the totem pole module includes a first switch tube and a second switch tube, and the first switch tube and the second switch tube are both electrically connected to the soft switch module; wherein, when the totem pole module operates in a positive half cycle, and the first switch tube is turned on and the second switch tube is turned off, the soft switch module forms a parallel circuit with the first switch tube, and a series circuit with the second switch tube, so that the first switch tube is turned off at zero current and the second switch tube is turned on at zero voltage; when the totem pole module operates in a negative half cycle, and the second switch tube is turned on and the first switch tube is turned off, the soft switch module forms a parallel circuit with the second switch tube, and a series circuit with the first switch tube, so that the second switch tube is turned off at zero current and the first switch tube is turned on at zero voltage. Since the soft switch totem pole circuit provided by the present application adds a soft switch module on the basis of the existing totem pole module, it realizes zero current disconnection of one switch tube and zero voltage conduction of the other switch tube through the hardware circuit, so it can realize soft switching of two switch tubes at the same time. And because it is realized by hardware circuit, it will not cause the temperature rise problem of the switch tube.

[0089] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A soft switching totem pole circuit (100), characterized in that: The soft switch totem pole circuit (100) comprises a totem pole module (110) and a soft switch module (120), the totem pole module (110) comprising a first switch tube (Q1) and a second switch tube (Q2), the first switch tube (Q1) and the second switch tube (Q2) being electrically connected to the soft switch module (120); wherein: When the totem pole module (110) operates in a positive half cycle, and the first switch tube (Q1) is turned on and the second switch tube (Q2) is turned off, the soft switch module (120) forms a parallel circuit with the first switch tube (Q1) and a series circuit with the parasitic capacitance of the second switch tube (Q2), so that the first switch tube (Q1) is turned off with zero current and the second switch tube (Q2) is turned on with zero voltage; When the totem pole module (110) operates in the negative half cycle, and the second switch tube (Q2) is turned on and the first switch tube (Q1) is turned off, the soft switch module (120) forms a parallel circuit with the second switch tube (Q2) and a series circuit with the parasitic capacitance of the first switch tube (Q1), so that the second switch tube (Q2) is turned off with zero current and the first switch tube (Q1) is turned on with zero voltage; The soft switch module (120) comprises a first soft switch circuit (121) and a second soft switch circuit (122), wherein the first soft switch circuit (121) is connected in series with the first switch tube (Q1), the second soft switch circuit (122) is connected in series with the second switch tube (Q2), and the first soft switch circuit (121) is electrically connected with the second soft switch circuit (122); wherein: When the totem pole module (110) operates in a positive half cycle, and the first switch tube (Q1) is turned on and the second switch tube (Q2) is turned off, the first switch tube (Q1) is connected in parallel with the second soft switch loop (122), and the parasitic capacitance of the second switch tube (Q2) is connected in series with the second soft switch loop (122); When the totem pole module (110) operates in a negative half cycle, and the second switch tube (Q2) is turned on and the first switch tube (Q1) is turned off, the second switch tube (Q2) is connected in parallel with the first soft switch loop (121), and the parasitic capacitance of the first switch tube (Q1) is connected in series with the first soft switch loop (121); The first soft switch loop (121) comprises a third switch tube (Q3), a first inductor (L1) and a first diode (D1); the second soft switch loop (122) comprises a fourth switch tube (Q4), a second inductor (L2) and a second diode (D2); a first end of the third switch tube (Q3) is electrically connected to one end of the first switch tube (Q1); a second end of the third switch tube (Q3) is electrically connected to one end of the first inductor (L1); the other end of the first inductor (L1) is electrically connected to one end of the second inductor (L2), an anode of the first diode (D1) and a cathode of the second diode (D2); the cathode of the first diode (D1) is electrically connected to the other end of the first switch tube (Q1); the anode of the second diode (D2) is electrically connected to one end of the second switch tube (Q2); the other end of the second inductor (L2) is electrically connected to the first end of the fourth switch tube (Q4); and the second end of the fourth switch tube (Q4) is electrically connected to the other end of the second switch tube (Q2); The soft switch totem pole circuit (100) further comprises a control module, wherein the control module is electrically connected to the control ends of the first switch tube (Q1), the second switch tube (Q2), the third switch tube (Q3) and the fourth switch tube (Q4) respectively; wherein: When the totem pole module (110) operates in a positive half cycle, and the first switch tube (Q1) is turned on and the second switch tube (Q2) is turned off, the control module is used to control the fourth switch tube (Q4) to be turned on, then control the first switch tube (Q1) to be turned off after a first preset time, and control the second switch tube (Q2) to be turned on after a second preset time; When the totem pole module (110) operates in a negative half cycle, and the second switch tube (Q2) is turned on and the first switch tube (Q1) is turned off, the control module is used to control the third switch tube (Q3) to be turned on, then control the second switch tube (Q2) to be turned off after a first preset time, and control the first switch tube (Q1) to be turned on after a second preset time.

2. The soft switching totem pole circuit (100) according to claim 1, characterized in that: The soft switch module (120) further comprises a third diode (D3), an anode of the third diode (D3) being electrically connected to the other end of the second inductor (L2), and a cathode of the third diode (D3) being electrically connected to one end of the first switch tube (Q1).

3. The soft switching totem pole circuit (100) according to claim 1, characterized in that: The totem pole module (110) further comprises a third inductor (L3), a fourth diode (D4), a fifth diode (D5) and a capacitor (E); one end of the third inductor (L3) is electrically connected to the live wire of the AC power supply; the other end of the third inductor (L3) is respectively connected to the first switch tube (Q1) and the second switch tube (Q2); the neutral wire of the AC power supply is respectively electrically connected to the anode of the fourth diode (D4) and the cathode of the fifth diode (D5); the cathode of the fourth diode (D4) is respectively electrically connected to the first switch tube (Q1) and one end of the capacitor (E); the other end of the capacitor (E) is respectively connected to the anode of the fifth diode (D5) and the second switch tube (Q2).

4. An air conditioner, characterized in that: The air conditioner comprises the soft switching totem pole circuit (100) according to any one of claims 1 to 3.

5. A soft switching totem pole circuit (100) control method, characterized in that: The method is applied to the soft switching totem pole circuit (100) according to any one of claims 1 to 3, and the method comprises: When the totem pole module (110) operates in a positive half cycle, and the first switch tube (Q1) is turned on and the second switch tube (Q2) is turned off, the soft switch module (120) is controlled to operate so that the first switch tube (Q1) is turned off at zero current and the second switch tube (Q2) is turned on at zero voltage; When the totem pole module (110) operates in the negative half cycle, and the second switch tube (Q2) is turned on and the first switch tube (Q1) is turned off, the soft switch module (120) is controlled to operate so that the second switch tube (Q2) is turned off at zero current and the first switch tube (Q1) is turned on at zero voltage.

6. The soft switching totem pole circuit (100) control method according to claim 5, characterized in that: The soft switch module (120) comprises a first soft switch circuit (121) and a second soft switch circuit (122), wherein the first soft switch circuit (121) is connected in series with the first switch tube (Q1), the second soft switch circuit (122) is connected in series with the second switch tube (Q2), and the first soft switch circuit (121) is electrically connected with the second soft switch circuit (122); when the totem pole module (110) operates in a positive half cycle, the step of controlling the operation of the soft switch module (120) comprises: Controlling the second soft switch loop (122) to be turned on and the first soft switch loop (121) to be turned off; After the step of the soft switch module (120) operating, the method further comprises: Controlling the first switch tube (Q1) to be disconnected after a first preset time, so that the first switch tube (Q1) is disconnected at zero current; After a second preset time, controlling the second switch tube (Q2) to be turned on, so that the second switch tube (Q2) is turned on at zero voltage; When the totem pole module (110) operates in the negative half cycle, the step of controlling the soft switch module (120) to operate comprises: Controlling the first soft switch loop (121) to be turned on and the second soft switch loop (122) to be turned off; After the step of the soft switch module (120) operating, the method further comprises: After a first preset time, the second switch tube (Q2) is controlled to be disconnected, so that the second switch tube (Q2) is disconnected with zero current; After a second preset time, the first switch tube (Q1) is controlled to be turned on, so that the first switch tube (Q1) is turned on at zero voltage.

7. The soft switching totem pole circuit (100) control method according to claim 5, characterized in that: When the totem pole module (110) operates in a positive half cycle, before the step of controlling the soft switch module (120) to operate, the method further comprises: Controlling the first switch tube (Q1) to be disconnected, and controlling the second switch tube (Q2) to be turned on; After a preset time, controlling the second switch tube (Q2) to be turned off and the first switch tube (Q1) to be turned on; When the totem pole module (110) operates in the negative half cycle, before the step of controlling the soft switch module (120) to operate, the method further comprises: Controlling the second switch tube (Q2) to be disconnected, and controlling the first switch tube (Q1) to be turned on; After a preset time, the first switch tube (Q1) is controlled to be disconnected and the second switch tube (Q2) is controlled to be closed.

Images