Air conditioning system

Abstract

The invention discloses an air conditioning system, relates to the technical field of electronics, and aims to solve the problems that when a switching tube is switched on and switched off, the current on a BUCK inductor has an oscillation waveform, so that in an EMC (Electro Magnetic Compatibility) test, relatively large interference is caused, and the allowance is insufficient. The air conditioning system comprises a main control board. And the BUCK power supply is coupled with the main control board, and the BUCK power supply is configured to supply power to the main control board. The BUCK power supply comprises a first inductor, a second inductor and a first capacitor, the first inductor and the second inductor are connected in series, the first capacitor and the second inductor are connected in parallel, and the first inductor and the second inductor are coupled between a control chip of the BUCK power supply and the output end of the BUCK power supply.

Description

Technical Field

[0001] The present invention relates to the field of electronic technology, and in particular to an air conditioning system. Background Art

[0002] With the improvement of people's living standards, air conditioning has become an indispensable part of people's daily life.

[0003] Currently, when performing electromagnetic compatibility (EMC) testing on the BUCK architecture, due to the large distributed capacitance in the BUCK architecture, when the switch tube is turned on and off, the current on the BUCK inductor will have an oscillating waveform, resulting in large interference and insufficient margin in the EMC test, that is, the distance between the quasi-peak value of the EMC test waveform and the standard line.

[0004] Among them, the pulse spike in the EMC test waveform may have enough amplitude to make the SA set to the peak detection function have a very large reception level, but the quasi-peak level may not exceed the limit. However, if the quasi-peak level exceeds the limit, then the peak level will definitely exceed the limit. The pulse spike will not seriously hinder the communication receiver from obtaining the required information, but the modulation of a continuous signal will result in a continuous radio detection signal, thus seriously interfering with the listener's acquisition of useful information. Summary of the invention

[0005] The embodiment of the present invention provides an air conditioning system, which solves the problem that when the switch tube is turned on and off, the current on the buck inductor has an oscillating waveform, resulting in greater interference and insufficient margin in EMC testing.

[0006] To achieve the above object, the embodiments of the present invention adopt the following technical solutions:

[0007] In a first aspect, the present application provides an air conditioning system, comprising: a main control board. A BUCK power supply, the BUCK power supply is coupled to the main control board, and the BUCK power supply is configured to supply power to the main control board. The BUCK power supply comprises a first inductor, a second inductor, and a first capacitor, the first inductor and the second inductor are connected in series, the first capacitor and the second inductor are connected in parallel, and the first inductor and the second inductor are coupled between a control chip of the BUCK power supply and an output terminal of the BUCK power supply. The second inductor and the first capacitor are used to reduce the sum of the capacitance values ​​of the distributed capacitance of the BUCK power supply.

[0008] Therefore, by connecting a capacitor in parallel to the inductor in the buck power supply, the sum of the capacitance of the distributed capacitance of the inductor and the capacitance of the capacitor becomes larger. After the inductor and the capacitor are connected in parallel, they are connected in series to the inductor, thereby reducing the sum of the capacitance of the distributed capacitance of the buck power supply.

[0009] In some embodiments, a difference between a sum of a capacitance of the first capacitor and a capacitance of a distributed capacitance of the second inductor and the distributed capacitance of the first inductor is within a preset range.

[0010] In some embodiments, a difference between a sum of a capacitance of the first capacitor and a capacitance of a distributed capacitance of the second inductor and the distributed capacitance of the first inductor is within a preset range.

[0011] In some embodiments, the sum of the capacitance of the first capacitor and the capacitance of the distributed capacitance of the second inductor is equal to the distributed capacitance of the first inductor.

[0012] In some embodiments, the distributed capacitance includes the distributed capacitance between the wire and the magnetic core in the first inductor and the second inductor, the distributed capacitance between each turn of the wire in the first inductor and the second inductor, and the distributed capacitance between the wires in the same layer in the first inductor and the second inductor.

[0013] In some embodiments, the first inductor is a magnetic core made of nickel-zinc material, and the second inductor is a magnetic bead inductor.

[0014] In some embodiments, the sum of the capacitances of the distributed capacitance of the BUCK power supply is the ratio of the first capacitance to the second capacitance. The first capacitance is the product of the capacitance of the distributed capacitance of the first inductor and the third capacitance, the third capacitance is the sum of the capacitance of the first capacitance and the capacitance of the distributed capacitance of the second inductor, and the second capacitance is the sum of the capacitance of the distributed capacitance of the first inductor and the third capacitance.

[0015] In some embodiments, the BUCK power supply further includes an AC power input terminal of the BUCK power supply, a rectifier bridge, a second capacitor, a third capacitor, a fourth capacitor, a first diode, and a second diode.

[0016] In some embodiments, the rectifier bridge is configured to convert the AC power output from the AC power input terminal into DC power. The second capacitor, the third capacitor, and the fourth capacitor are configured to provide voltage to the BUCK power supply. The first diode and the second diode are configured to make the current in the BUCK power supply unidirectional.

[0017] In some embodiments, the AC power supply is coupled to the rectifier bridge, the rectifier bridge is coupled to the control chip and the second capacitor (C1), the control chip is also coupled to the first diode (D1) and the third capacitor (C2), the first diode (D1) is also coupled to the first inductor (L1), the first inductor (L1) is also coupled to the fourth capacitor (C3), and the fourth capacitor (C3) is also coupled to the second diode (D2). BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of a BUCK architecture;

[0019] Figure 2A simplified circuit diagram of a BUCK architecture;

[0020] Figure 3 is a schematic diagram of an oscillating waveform of a current on an inductor;

[0021] Figure 4 A schematic diagram of an EMC test waveform of a BUCK architecture;

[0022] Figure 5 is a schematic diagram of an inductor equivalent model;

[0023] Figure 6 is a schematic diagram of a nickel-zinc inductor;

[0024] Figure 7 This is a schematic diagram of the internal structure of a nickel-zinc inductor;

[0025] Figure 8 is a schematic diagram of a ferrite inductor;

[0026] Fig. 9 This is a schematic diagram of the internal structure of a ferrite inductor;

[0027] Fig.10 It is a schematic diagram of the structure of a magnetic core of a ferrite inductor;

[0028] Fig.11 A schematic diagram of the distributed capacitance of a winding inductor;

[0029] Fig.12 A schematic diagram of the structure of an air conditioning system provided for this application;

[0030] Fig.13 A schematic diagram of the structure of a BUCK power supply provided in this application;

[0031] Fig.14 An equivalent schematic diagram of a first inductor and a second inductor connected in series provided by the present application;

[0032] Fig.15 A schematic diagram of the structure of a BUCK power supply provided in this application;

[0033] Fig.16 A schematic diagram of the waveform of an EMC test of a BUCK power supply provided in this application;

[0034] Fig.17 A schematic diagram of a current waveform of an inductor in a BUCK power supply provided in the present application. DETAILED DESCRIPTION

[0035] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0036] In the description of the present invention, it is to be understood that the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0037] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the term "coupling" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, when describing pipelines or channels, the "connected" and "connected" used in this application have the meaning of conduction. The specific meaning needs to be understood in conjunction with the context.

[0038] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0039] The present application is applied to a BUCK architecture coupled to a main control board in an air-conditioning system.

[0040] The inductor L and capacitor C in the BUCK architecture form a low-pass filter. The design principle of this filter is to allow the DC component of the power input end of the BUCK architecture to pass through, while suppressing the harmonic component of the power input end of the BUCK architecture. The output voltage on the capacitor in the BUCK architecture is the DC component of the power input end of the BUCK architecture plus a small ripple.

[0041] The circuit operates at a very high frequency, and the ripple caused by the charging and discharging of the capacitor in a switching cycle is very small. Relative to the DC voltage output on the capacitor, the voltage on the capacitor can be considered constant on a macro scale. When the circuit is working in a steady state, the voltage on the output capacitor is composed of a tiny ripple and a larger DC component, which can be considered as a constant DC on a macro scale. This is the small ripple approximation principle in the steady-state analysis of the switching circuit.

[0042] When the charging charge of the capacitor is higher than the discharging charge in a cycle, the capacitor voltage increases, resulting in a decrease in the charging charge and an increase in the discharging charge in the subsequent cycles, which slows down the rise rate of the capacitor voltage. This process continues until the charge and discharge are balanced, at which time the voltage remains unchanged. Conversely, if the discharge charge in a cycle is higher than the charging charge, the charging charge will increase and the discharge charge will decrease in the subsequent cycles, which slows down the rate at which the capacitor voltage drops. This process continues until the charge and discharge are balanced, and the voltage is ultimately maintained unchanged. This process is a transitional process for adjusting the voltage on the capacitor. When the circuit is working in a steady state, the circuit reaches a stable balance, and the charge and discharge on the capacitor also reach a balance. This is a general rule when the circuit is working in a steady state.

[0043] like Figure 1 As shown, Figure 1 A schematic diagram of a BUCK architecture 100 is shown. The BUCK architecture includes a control chip 101, an AC power input terminal AC, a rectifier bridge DM, a capacitor C1, a capacitor C2, a capacitor C3, a diode D1, a diode D2 and an inductor L1. Among them, the control chip 101 includes a switch tube, for example, it can be a triode or a metal oxide semiconductor field effect transistor (metal-oxide-semiconductor field-effect transistor, MOSFET). This application is explained by taking the MOSFET tube as an example. The MOSFET tube is a field effect transistor (field-effect transistor) that can be widely used in analog circuits and digital circuits. MOSFET can be divided into two types of "N-type" and "P-type" according to the polarity of its "channel" (working carrier), which is usually called NMOSFET and PMOSFET. Other abbreviations include NMOS, PMOS, etc.

[0044] The control chip 101 is used to control the on and off of the switch tube.

[0045] The switch tube is used to turn on or off the current in the BUCK architecture 100 .

[0046] Capacitor C1 is a high voltage large electrolytic capacitor.

[0047] Capacitor C2 is a small electrolytic capacitor for power supply.

[0048] Inductor L1 is used to convert electrical energy into magnetic energy for storage, and can also convert the stored magnetic energy into electrical energy for release. When converting between magnetic energy storage and electrical energy release, the positive and negative poles of inductor L1 change in the opposite direction. However, the current flowing through inductor L1 cannot change suddenly, but can only increase or decrease gradually.

[0049] Capacitor C3 has the function of storing electricity. It discharges when the voltage across the capacitor C3 is higher than the voltage of the external circuit, and charges when it is lower than the voltage of the external circuit. Unlike the inductor L, the capacitor C3 does not change its positive and negative poles when charging and discharging.

[0050] Diode D1 and diode D2 have positive and negative pole characteristics and conduct electricity in one direction. Current can flow only when the positive poles are connected to each other, otherwise it cannot flow.

[0051] The diode D1 can also be understood as a freewheeling diode.

[0052] The rectifier bridge DM is a bridge rectifier circuit, which consists of four diodes connected in a closed-loop "bridge" configuration to produce the desired output. It is the most commonly used circuit for rectifying by utilizing the unidirectional conductivity of the diode, and is often used to convert AC into DC. The bridge rectifier circuit uses four diodes, connected in pairs. When the positive half of the input sine wave is turned on, two tubes are turned on to obtain a positive output. When the negative half of the sine wave is input, the other two tubes are turned on. Since these two tubes are reversely connected, the output still obtains the positive half of the sine wave. The 220V AC voltage input at the AC power input terminal AC outputs a DC high voltage through the rectifier bridge DM, which can be 300V, for example.

[0053] The working principle of the BUCK architecture 100 is introduced below.

[0054] like Figure 2 As shown, Figure 2 FIG. 1 shows a simplified circuit diagram of a BUCK architecture 100. As can be seen from the figure, the simplified BUCK architecture 100 includes a power input terminal V in , control chip 101, capacitor C3, inductor L1 and diode D1. Power input terminal V in The positive electrode of the control chip is coupled to the first end of the control chip at terminal A, the second end of the control chip is coupled to the first end of the inductor L1 and the cathode of the diode D1 at terminal B, the second end of the inductor L1 and the first end of the capacitor C3 are coupled to terminal C, the second end of the capacitor C3 and the anode of the diode D1 are coupled to terminal D, the anode of the diode D1 is also coupled to the ground terminal at terminal E, and the power input terminal V in The negative terminal and the ground terminal are coupled to terminal F.

[0055] Among them, the power input terminal V in Outputs DC high voltage.

[0056] When the switch is turned on, the current flows from the power input terminal V in The positive electrode flows out and returns to the power input terminal V through the inductor L1 and capacitor C3 inThe negative pole of the inductor L1. When the current flows through the inductor L1, the left end of the inductor L1 is the positive pole, and the right end of the inductor L1 is the negative pole. The inductor L1 converts the electrical energy into magnetic energy and stores it. When the current flows through the capacitor C3, the capacitor C3 is charged. That is, when the switch tube is turned on, the current flow loop is ABCDEF.

[0057] When the switch is turned off, the power input terminal V in When the power supply is no longer supplied, the inductor L1 converts the stored magnetic energy into electrical energy for release, that is, the inductor L1 becomes the power supply in the BUCK architecture 100. At this time, the left end of the inductor L1 is the negative pole, and the right end of the inductor L1 is the positive pole. The current flows out from the right end of the inductor L1 and returns to the left end of the inductor L1 through the capacitor C3 and the diode D1. It can be seen that the current released by the inductor L1 will change from large to small. That is, when the switch tube is disconnected, the current flow loop is BCDE.

[0058] It should be understood that when the switch is turned off and the polarity of the inductor L1 is reversed, the inductor L1 cannot supply power to the BUCK architecture 100 at this moment. At this time, the capacitor C3 supplies power to the load connected to the BUCK architecture 100.

[0059] Then, every time the switch tube is turned on and off, the current on the inductor L1 will have an oscillating waveform.

[0060] Figure 3 FIG. 1 is a schematic diagram showing an oscillating waveform of the current on the inductor L1 .

[0061] Depend on Figure 3 It can be seen that when the switch tube is turned on and off, the oscillation period of the noise current generated on the inductor L1 is 25 mega hertz (MHz).

[0062] Due to the existence of the noise current oscillation waveform, the BUCK architecture 100 has insufficient margin in the EMC test.

[0063] Among them, EMC testing is also called electromagnetic compatibility EMC, which refers to the comprehensive evaluation of the interference size (EMI) and anti-interference ability (EMS) of electronic products in the electromagnetic field. It is one of the most important indicators of product quality. The measurement of electromagnetic compatibility consists of test sites and test instruments.

[0064] like Figure 4 , a schematic diagram of an EMC test waveform of a BUCK architecture 100 is shown.

[0065] The horizontal axis represents the frequency of the EMC test waveform, and the vertical axis represents the voltage of the EMC test waveform. The waveform X1 represents the quasi-peak value of the EMC test waveform, and the waveform X2 represents the average value of the EMC test waveform.

[0066] Depend on Figure 4 It can be seen that the margin between the quasi-peak value of the EMC test waveform and the standard line is small.

[0067] The noise current generated when the switch tube is turned on and off is mainly due to the distributed capacitance in the BUCK architecture 100 .

[0068] like Figure 5 As shown, a schematic diagram of an equivalent model of inductor L1 is shown. Among them, there are two designs of inductor L1, one is a magnetic core made of nickel-zinc material, and the other is a magnetic core made of ferrite material, wherein the inductor L1 of the magnetic core made of nickel-zinc material and the inductor L1 of the magnetic core made of ferrite material are both winding inductors. The equivalent model of inductor L1 includes a resistor R, an inductor L and a capacitor C. This application is explained by taking a winding inductor as an example. It should be noted that when the nickel-zinc inductor is sintered by itself, there is a tiny air gap inside, and the ferrite core needs to have an air gap.

[0069] Depend on Figure 5 It can be seen that the inductor L1 can be equivalent to a resistor R, an inductor L and a capacitor C.

[0070] The resistor R and the inductor L are connected in series, and the capacitor C is connected in parallel with the series-connected resistor R and inductor L.

[0071] like Figure 6 As shown, a schematic diagram of a nickel-zinc inductor is shown.

[0072] like Figure 7 , which shows the internal schematic diagram of a nickel-zinc inductor.

[0073] Depend on Figure 7 It can be seen that the nickel-zinc inductor is a winding inductor.

[0074] like Figure 8 As shown, a schematic diagram of a ferrite inductor is shown.

[0075] Among them, ferrite materials are iron-magnesium alloys or iron-nickel alloys. This material has a high magnetic permeability. It can minimize the capacitance between the coil windings of the inductor under high frequency and high resistance conditions. Ferrite materials are usually used in high frequency conditions because at low frequencies they mainly show inductance characteristics, which makes the loss on the line very small. At high frequencies, they mainly show reactance characteristics and change with frequency.

[0076] like Fig. 9 , which shows the internal schematic diagram of a ferrite inductor.

[0077] Depend on Fig. 9 It can be seen that ferrite inductor is a winding inductor.

[0078] like Fig.10As shown, a schematic diagram of a ferrite inductor core is shown.

[0079] Ferrite cores are mainly composed of three metal elements: iron (Fe), manganese (Mn), and zinc (Zn), and are usually called manganese-zinc ferrite. Ring ferrite cores have a high magnetic effect because they have no air gap and a uniform cross-sectional area.

[0080] Fig.11 A schematic diagram of the distributed capacitance of a wound inductor is shown.

[0081] Distributed capacitance is formed by two conductors that have a voltage difference and are insulated from each other. Therefore, in any circuit, any two insulated conductors with a voltage difference will form distributed capacitance, it’s just a matter of size.

[0082] There are distributed capacitances between turns of the coil, between the coil and the ground, between the coil and the shielding box, and between the layers of the coil. The existence of distributed capacitance will increase the equivalent total loss resistance of the coil and reduce the quality factor Q. High-frequency coils often use the honeycomb winding method, that is, the plane of the wound coil is not parallel to the rotating plane, but intersects at a certain angle. This type of coil is called a honeycomb coil. The number of times the wire bends back and forth when the coil rotates one circle is called the number of inflection points. The advantages of the honeycomb winding method are small size, small distributed capacitance, and low inductance. Honeycomb coils are all wound using a honeycomb winding machine. The more inflection points there are, the smaller the distributed capacitance.

[0083] Wherein, CTC represents the distributed capacitance between the conductor and the magnetic core.

[0084] CTT represents the distributed capacitance between each turn of the wire.

[0085] CTL represents the distributed capacitance between wires on the same layer.

[0086] Currently, due to the large distributed capacitance in the BUCK architecture, noise current is generated, resulting in a small margin between the quasi-peak value and the standard line of the EMC test waveform when the BUCK architecture 100 is subjected to EMC testing.

[0087]

[0088] Where I is the noise current, C 总 represents the sum of the distributed capacitance in the BUCK architecture 100. dv / dt is the switching acceleration of the control chip in the BUCK architecture 100. If the control chip in the BUCK architecture 100 is fixed, the value of dv / dt generally does not change. Then the only reason for the large noise current I is C 总 .

[0089] In view of this, the present application reduces the distributed capacitance in the BUCK architecture, reduces the oscillation waveform of the noise current in the BUCK architecture, and thus reduces the margin between the quasi-peak value of the EMC test waveform and the standard line.

[0090] like Fig.12 , which is a schematic diagram of the structure of an air conditioning system 200 provided in the present application. The air conditioning system includes a main control board 1201 and a BUCK power supply 1202. The BUCK power supply 1202 is coupled to the main control board 1201. The air conditioning system 200 may be, for example, a central air conditioning system, which is not limited in the present application.

[0091] Among them, the central air conditioning system has a host and a terminal system. The medium used to bear the indoor heat and humidity load can be divided into a full air system, a full water system, an air-water system, and a refrigerant system. According to the degree of centralization of air handling equipment, it can be divided into centralized and semi-centralized. According to the source of the treated air, it can be divided into closed type, direct current type, and mixed type (primary return air and secondary return air). The main components include air conditioning host (cold and heat source), combined air conditioning unit (wind cabinet), fan coil, etc.

[0092] The BUCK power supply 1202 is configured to supply power to the main control board.

[0093] like Fig.13 , which is a schematic diagram of the structure of a BUCK power supply 1202 provided by the present application. The BUCK power supply 1202 includes a first inductor L1, a second inductor L2 and a first capacitor C4, the first inductor L1 and the second inductor L2 are connected in series, the first capacitor C4 and the second inductor L2 are connected in parallel, and the first inductor L1 and the second inductor L2 are coupled between the control chip of the BUCK power supply and the output terminal of the BUCK power supply.

[0094] The inductor L2 here may be, for example, a magnetic bead inductor. It should be understood that the distributed capacitance of the magnetic bead inductor L2 has a very small capacitance.

[0095] In some embodiments, the sum of the capacitances of the distributed capacitance of the BUCK power supply is the ratio of the first capacitance to the second capacitance. The first capacitance is the product of the capacitance of the distributed capacitance of the first inductor and the third capacitance, the third capacitance is the sum of the capacitance of the first capacitance and the capacitance of the distributed capacitance of the second inductor, and the second capacitance is the sum of the capacitance of the distributed capacitance of the first inductor and the third capacitance.

[0096] Exemplarily, the sum of the capacitance of the distributed capacitance of the BUCK power supply 1202 is expressed as:

[0097]

[0098] Among them, c 总represents the sum of the capacitance of the distributed capacitance of the BUCK power supply 1202, C1 represents the capacitance of the distributed capacitance of the first inductor L1, and C2 represents the sum of the capacitance of the first capacitor C4 and the capacitance of the distributed capacitance of the second inductor L2. It can be seen that the first capacitance is C1*C2, and the third capacitance is C1+C2.

[0099] like Fig.14 As shown, it is an equivalent schematic diagram of an inductor L1 and an inductor L2 connected in series provided by the present application.

[0100] Assuming that the capacitance of the first capacitor C4 is a, and the capacitance of the distributed capacitance of the second inductor L2 is b, then C2 = a + b. It can be understood that when the capacitance C2 is larger, C 总 The smaller.

[0101] The second inductor L2 and the first capacitor C4 are used to reduce the total capacitance of the distributed capacitance of the BUCK power supply 1202 .

[0102] Therefore, by connecting a capacitor C4 in parallel to the inductor L1 in the BUCK power supply 1202, the sum of the capacitance of the distributed capacitance of the inductor L1 and the capacitance of the capacitor C4 becomes larger. After the inductor L1 and the capacitor C4 are connected in parallel, they are connected in series to the inductor L1, thereby reducing the sum of the capacitance of the distributed capacitance of the BUCK power supply 1202.

[0103] In some embodiments, in order to effectively reduce the total capacitance of the distributed capacitors in the BUCK power supply 1202 .

[0104] The difference between the sum of the capacitance of the first capacitor C4 and the capacitance of the distributed capacitance of the second inductor L2 and the distributed capacitance of the first inductor is within a preset range.

[0105] Exemplarily, the difference between the sum of the capacitance of the first capacitor C4 and the capacitance of the distributed capacitance of the second inductor L2 and the distributed capacitance of the first inductor may be 0. That is, the sum of the capacitance of the first capacitor C4 and the capacitance of the distributed capacitance of the second inductor L2 is equal to the distributed capacitance of the first inductor L1.

[0106] In some embodiments, the distributed capacitance includes the distributed capacitance between the wire and the magnetic core in the first inductor and the second inductor, the distributed capacitance between each turn of the wire in the first inductor and the second inductor, and the distributed capacitance between the wires in the same layer in the first inductor and the second inductor.

[0107] Exemplarily, the distributed capacitance includes the distributed capacitance between the wire and the magnetic core in the first inductor and the second inductor, the distributed capacitance between each turn of the wire in the first inductor and the second inductor, and the distributed capacitance between the wires in the same layer in the first inductor and the second inductor.

[0108] The first inductor L1 is a magnetic core made of nickel-zinc material.

[0109] In some embodiments, the BUCK power supply 1202 further includes an AC power input terminal of the BUCK power supply, a rectifier bridge, a second capacitor C1, a third capacitor C2, a fourth capacitor C3, a first diode D1, and a second diode D2. The AC power supply is coupled to the rectifier bridge, the rectifier bridge is coupled to the control chip and the second capacitor C1, the control chip is also coupled to the first diode D1 and the third capacitor C2, the first diode D1 is also coupled to the first inductor L1, the first inductor L1 is also coupled to the fourth capacitor C3, and the fourth capacitor C3 is also coupled to the second diode D2. The rectifier bridge is configured to convert the AC power output from the AC power input terminal into DC power.

[0110] The second capacitor C1 , the third capacitor C2 , and the fourth capacitor C3 are configured to provide voltage to the BUCK power supply.

[0111] The first diode D1 and the second diode D2 are configured to conduct the current in the BUCK power supply in a unidirectional manner.

[0112] The rectifier bridge, the second capacitor C1, the third capacitor C2, the fourth capacitor C3, the first diode D1 and the second diode D2 have been introduced above and will not be repeated here.

[0113] like Fig.15 As shown, it is a structural schematic diagram of a BUCK power supply 1202 provided by the present application. The AC power input end is coupled between the first end and the second end of the rectifier bridge, the third end of the rectifier bridge is coupled to the first end of the switch tube in the control chip, the fourth end of the rectifier bridge is coupled to the first end of the second capacitor C1, the second end of the second capacitor C1 is coupled between the first pin DR AIN of the control chip and the first end of the switch tube, the second end of the switch tube is coupled to the second pin GND_IC of the control chip, the second pin GND_IC of the control chip is coupled between the first end of the second inductor L2 and the first end of the first capacitor C4, the second end of the second inductor L2 and the second end of the first capacitor C4 are coupled to the first end of the first inductor L1, the first end of the second inductor L2 and the first end of the first capacitor C4 are also coupled to the first end of the first diode D1, the second end of the first diode D1 is coupled to the first end of the fourth capacitor C3, the second end of the fourth capacitor C3 and the first end of the first inductor L1 are coupled to the first end of the first inductor L2, and the first end of the first capacitor C4 is coupled to the first end of the first diode D1. The second end of the first inductor L1 is coupled, the second end of the first inductor L1 is also coupled to the first end of the second diode D2, the second end of the second diode D2 is coupled between the third pin VCC of the control chip and the first end of the third capacitor C2, the second end of the third capacitor C2 is coupled between the second pin GND_IC of the control chip and the first end of the second inductor L2, the first end of the second capacitor C1, the second end of the first diode D1 and the first end of the fourth capacitor C3 are also coupled to the ground end, and the first end of the second diode D2 is also coupled to the output end Vout of the BUCK power supply.

[0114] The AC power input terminal is used to provide 220V AC power to the BUCK power supply 1202 .

[0115] The rectifier bridge is used to rectify the AC power output from the AC power input end to obtain DC power.

[0116] like Fig.16 , which is a waveform diagram of an EMC test of a BUCK power supply 1202 provided in the present application.

[0117] Depend on Fig.16 It can be seen that compared with Figure 4 , the margin between the quasi-peak value of the EMC test waveform and the standard line becomes larger.

[0118] like Fig.17 , which is a schematic diagram of a current waveform of an inductor L1 in a BUCK power supply 1202 provided by the present application.

[0119] Depend on Fig.17 It can be seen that compared with Figure 3 , the oscillation waveform of the noise current on the inductor L1 with an oscillation period of 25 MHz disappeared.

[0120] Therefore, the present application increases the sum of the capacitance of the distributed capacitance of the inductor and the capacitance of the capacitor by connecting a capacitor in parallel to the inductor in the BUCK power supply. After the inductor and the capacitor are connected in parallel, they are connected in series to the inductor, thereby reducing the sum of the capacitance of the distributed capacitance of the BUCK power supply. As a result, there is no oscillating waveform of the noise current in the BUCK power supply, and the margin between the quasi-peak value and the standard line of the EMC test waveform of the BUCK power supply 1202 in the EMC test becomes larger.

[0121] Although the present application is described herein in conjunction with various embodiments, in the process of implementing the claimed application, those skilled in the art may understand and implement other changes to the disclosed embodiments by viewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "one" or "an" does not exclude multiple situations. A single processor or other unit may implement several functions listed in the claims. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0122] Although the present application has been described in conjunction with specific features and embodiments thereof, it is obvious that various modifications and combinations may be made thereto without departing from the spirit and scope of the present application. Accordingly, this specification and the drawings are merely exemplary illustrations of the present application as defined by the appended claims, and are deemed to have covered any and all modifications, variations, combinations or equivalents within the scope of the present application. Obviously, those skilled in the art may make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

[0123] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An air conditioning system, characterized in that: include: A main control board, the main control board is configured to control the air conditioning system to be turned on or off; A BUCK power supply, the BUCK power supply is coupled to the main control board, and the BUCK power supply is configured to supply power to the main control board; The BUCK power supply includes a first inductor, a second inductor and a first capacitor, the first inductor and the second inductor are connected in series, the first capacitor and the second inductor are connected in parallel, and the first inductor and the second inductor are coupled between a control chip of the BUCK power supply and an output terminal of the BUCK power supply; The second inductor and the first capacitor are used to reduce the total capacitance of the distributed capacitance of the BUCK power supply.

2. The air conditioning system according to claim 1, characterized in that: A difference between a sum of a capacitance of the first capacitor and a capacitance of the distributed capacitance of the second inductor and the distributed capacitance of the first inductor is within a preset range.

3. The air conditioning system according to claim 2, characterized in that: The sum of the capacitance of the first capacitor and the capacitance of the distributed capacitance of the second inductor is equal to the distributed capacitance of the first inductor.

4. The air conditioning system according to claim 3, characterized in that: The distributed capacitance includes the distributed capacitance between the wire and the magnetic core in the first inductor and the second inductor, the distributed capacitance between each turn of the wire in the first inductor and the second inductor, and the distributed capacitance between the wires in the same layer in the first inductor and the second inductor.

5. The air conditioning system according to any one of claims 1 to 4, characterized in that: The first inductor is a magnetic core made of nickel-zinc material; The second inductor is a magnetic bead inductor.

6. The air conditioning system according to claim 2, characterized in that: The sum of the capacitances of the distributed capacitances of the BUCK power supply is the ratio of the first capacitance to the second capacitance; The first capacitance is the product of the capacitance of the distributed capacitance of the first inductor and the third capacitance, and the third capacitance is the sum of the capacitance of the first capacitance and the capacitance of the distributed capacitance of the second inductor; The second capacitance is the sum of the capacitance of the distributed capacitance of the first inductor and the third capacitance.

7. The air conditioning system according to any one of claims 1 to 4, characterized in that: The BUCK power supply further includes an AC power input terminal of the BUCK power supply, a rectifier bridge, a second capacitor, a third capacitor, a fourth capacitor, a first diode and a second diode.

8. The air conditioning system according to claim 7, characterized in that: The rectifier bridge is configured to convert the AC power output from the AC power input end into DC power; The second capacitor, the third capacitor and the fourth capacitor are configured to provide a voltage to the BUCK power supply; The first diode and the second diode are configured to conduct the current in the BUCK power supply in a unidirectional manner.

9. The air conditioning system according to claim 8, characterized in that: The AC power supply is coupled to the rectifier bridge, the rectifier bridge is coupled to the control chip and the second capacitor, the control chip is also coupled to the first diode and the third capacitor, the first diode is also coupled to the first inductor, the first inductor is also coupled to the fourth capacitor, and the fourth capacitor is also coupled to the second diode.

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