An air conditioner

Abstract

This invention provides an air conditioner, relating to the field of electrical technology. The air conditioner reduces electromagnetic interference by modifying the transformer. The air conditioner includes: a substrate; the substrate includes an electromagnetic compatibility (EMC) module; the EMC module includes a transformer; the transformer includes: a magnetic core, a primary winding and a secondary winding sequentially wound around the magnetic core; the transformer further includes: a first shielding winding and / or a second shielding winding; the first shielding winding is located between the magnetic core and the primary winding, and the second shielding winding is located between the primary winding and the secondary winding; the windings of the first shielding winding and the primary winding are opposite; wherein the primary winding generates a first displacement current to the first shielding winding, the magnetic core generates a second displacement current to the first shielding winding (the two currents are in opposite directions), the primary winding generates a third displacement current to the second shielding winding, and the secondary winding generates a fourth displacement current to the second shielding winding (the two currents are in opposite directions). This invention is used to reduce electromagnetic interference.

Description

Technical Field

[0001] This invention relates to the field of electrical technology, and more particularly to an air conditioner. Background Technology

[0002] With the development of science and technology, air conditioning is becoming more and more common, and more and more people's daily lives are closely related to air conditioning.

[0003] Currently, to meet electromagnetic compatibility (EMC) requirements, central air conditioning circuit boards in the industry mainly employ two architectures: the first architecture lacks Y capacitors in both the primary and secondary windings, resulting in higher EMC costs; the second architecture includes Y capacitors in both primary and secondary windings, offering lower costs but poorer anti-interference capabilities and isolation. When Y capacitors exist between the primary and secondary windings of a central air conditioning circuit board, the following three problems arise: poor anti-interference capability, as primary surge voltages (such as lightning strikes) may damage the pins of the main control chip; poor isolation, as a voltage exceeding 100V can be measured between the secondary winding and ground, which can cause adverse effects. Summary of the Invention

[0004] This invention provides an air conditioner that reduces electromagnetic interference by modifying the transformer.

[0005] The air conditioner includes: a substrate; the substrate includes an electromagnetic compatibility module; the electromagnetic compatibility module includes a transformer; the transformer includes a magnetic core, a primary winding, and a secondary winding; the primary winding is wound around the magnetic core, the secondary winding is wound around the magnetic core, and the secondary winding is located outside the primary winding.

[0006] The transformer further includes: a first shielding winding and / or a second shielding winding; the first shielding winding is located between the magnetic core and the primary winding, and the second shielding winding is located between the primary winding and the secondary winding; the winding method of the first shielding winding and the primary winding are opposite.

[0007] Wherein, the primary winding generates a first displacement current to the first shielding winding, and the magnetic core generates a second displacement current to the first shielding winding, the first displacement current and the second displacement current being in opposite directions; the primary winding generates a third displacement current to the second shielding winding, and the secondary winding generates a fourth displacement current to the second shielding winding; the third displacement current and the fourth displacement current are in opposite directions.

[0008] In some embodiments, the number of turns in the first shielding winding is less than the number of turns in the primary winding; the number of turns in the second shielding winding is less than the number of turns in the secondary winding, and the number of turns in the second shielding winding is less than the number of turns in the first shielding winding.

[0009] In some embodiments, the number of turns in the first shielding winding is less than 1 / 4 of the number of turns in the primary winding; the number of turns in the second shielding winding is 1 / 2 of the number of turns in the first shielding winding.

[0010] In some embodiments, the primary winding includes a first primary winding and a second primary winding, the first primary winding and the second primary winding being wound around the magnetic core, and the second primary winding being located outside the first primary winding.

[0011] The first shielding winding is located between the magnetic core and the first primary winding, and the second shielding winding is located between the second primary winding and the secondary winding.

[0012] In some embodiments, the electromagnetic compatibility module further includes: a first voltage terminal, a second voltage terminal, a primary ground terminal, and a secondary ground terminal; a first end of the primary winding is electrically connected to the first voltage terminal, and a second end of the primary winding is electrically connected to the primary ground terminal; a first end of the secondary winding is electrically connected to the second voltage terminal, and a second end of the secondary winding is electrically connected to the secondary ground terminal.

[0013] In some embodiments, the electromagnetic compatibility module further includes a Y capacitor located between the primary ground terminal and the secondary ground terminal.

[0014] In some embodiments, the electromagnetic compatibility module further includes: a line impedance stabilization network, which includes: a first stabilizing capacitor, a second stabilizing capacitor, a third stabilizing capacitor, a fourth stabilizing capacitor, a first inductor, a second inductor, a first resistor, a second resistor, and a ground terminal.

[0015] The first terminal of the first stabilizing capacitor is electrically connected to the first inductor; the second terminal of the first stabilizing capacitor is electrically connected to the first terminal of the third stabilizing capacitor; the first terminal of the second stabilizing capacitor is electrically connected to the second terminal of the first inductor; the second terminal of the second stabilizing capacitor is electrically connected to the first terminal of the first resistor; the second terminal of the first resistor is electrically connected to the first terminal of the second resistor; the second terminal of the second resistor is electrically connected to the first terminal of the fourth stabilizing capacitor; the second terminal of the third stabilizing capacitor is electrically connected to the first terminal of the second inductor; the second terminal of the fourth stabilizing capacitor is electrically connected to the second terminal of the second inductor; the second terminal of the first stabilizing capacitor is electrically connected to the ground terminal; and the second terminal of the first resistor is electrically connected to the ground terminal.

[0016] In some embodiments, the electromagnetic compatibility module further includes: a rectifier circuit, the rectifier circuit including: four identical diodes; a first terminal of the rectifier circuit is electrically connected to a first terminal of the second stabilizing capacitor, a second terminal of the rectifier circuit is electrically connected to a first terminal of the primary winding, a third terminal of the rectifier circuit is electrically connected to a second terminal of the fourth stabilizing capacitor, and a fourth terminal of the rectifier circuit is electrically connected to the primary ground terminal.

[0017] In some embodiments, the transformer further includes: a diode and a first electrolytic capacitor, wherein the positive terminal of the diode is electrically connected to a first terminal of the secondary winding, the negative terminal of the diode is electrically connected to a second voltage terminal, the negative terminal of the diode is electrically connected to the positive terminal of the first electrolytic capacitor, and the negative terminal of the first electrolytic capacitor is electrically connected to a second terminal of the secondary winding;

[0018] The electromagnetic compatibility module further includes: a second electrolytic capacitor, the first end of which is electrically connected to the first end of the primary winding, and the second end of which is electrically connected to the primary grounding terminal.

[0019] In some embodiments, the electromagnetic compatibility module further includes: a switching transistor, wherein the first terminal of the switching transistor is electrically connected to the primary winding, and the second terminal of the switching transistor is electrically connected to the primary ground terminal.

[0020] Based on the above technical solutions, some embodiments of the present invention provide an air conditioner that uses active displacement current technology, which only requires changing the transformer and adding a first shielding winding and a second shielding winding to solve the electromagnetic interference problem that exists when there is a Y capacitor between the primary winding and the secondary winding of the air conditioner substrate. Attached Figure Description

[0021] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the technical solutions of the present invention, and do not constitute a limitation on the technical solutions of the present invention.

[0022] Figure 1 A simplified electromagnetic compatibility circuit diagram is provided for embodiments of the present invention;

[0023] Figure 2 A system block diagram of an air conditioner provided in an embodiment of the present invention;

[0024] Figure 3 A circuit diagram of a simplified line impedance stabilization network provided in this embodiment of the invention;

[0025] Figure 4A A circuit diagram of a transformer in an air conditioner provided in an embodiment of the present invention;

[0026] Figure 4B A circuit diagram of a transformer in an air conditioner provided in an embodiment of the present invention;

[0027] Figure 5 A circuit diagram with the same number of turns in a winding is provided in an embodiment of the present invention;

[0028] Figure 6 A circuit diagram with different numbers of turns in the winding is provided for an embodiment of the present invention;

[0029] Figure 7 An auxiliary winding circuit diagram provided in an embodiment of the present invention;

[0030] Figure 8 A magnetic core-to-ground shielding circuit diagram provided in an embodiment of the present invention;

[0031] Figure 9 A schematic diagram of a transformer structure provided in an embodiment of the present invention;

[0032] Figure 10 An electromagnetic compatibility circuit diagram provided for an embodiment of the present invention;

[0033] Figure 11A An electromagnetic compatibility test diagram with a Y capacitor is provided in an embodiment of the present invention;

[0034] Figure 11B This is an electromagnetic compatibility test diagram without a Y capacitor provided in an embodiment of the present invention. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0037] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, when describing pipelines, the terms "connected" and "linked" as used in this invention have the meaning of enabling conduction. The specific meaning needs to be understood in conjunction with the context.

[0039] In embodiments of the present invention, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" or "for example" in embodiments of the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0040] As described in the background section, there are currently two main architectures for central air conditioning circuit boards in the industry to meet electromagnetic compatibility requirements: one is that there is no Y capacitor between the primary and secondary windings of the transformer, which has strong anti-interference ability and strong isolation, but high electromagnetic compatibility cost; the other is that there is a Y capacitor between the primary and secondary windings of the transformer, which has low electromagnetic compatibility cost, but poor anti-interference ability and poor isolation.

[0041] When there is a Y capacitor between the primary and secondary windings of the transformer on the central air conditioning board, the following three problems exist: (1) Poor anti-interference performance; primary surge voltage (such as lightning strike) may damage the pins of the main control chip. (2) Poor isolation; the secondary winding of the board can be measured to ground at a voltage of over 100V, which is easy to be complained about. (3) High cost of electromagnetic compatibility solution; without adding the Y capacitor between the primary and secondary windings, bulky filter components must be added to ensure electromagnetic compatibility.

[0042] like Figure 1 As shown, Figure 1This is a simplified electromagnetic compatibility (EMC) circuit diagram on an air conditioner circuit board. The circuit diagram 200 includes: an interference source X, a Y capacitor Cy, a parasitic capacitor Cs, an EMC sampling resistor Re, and a ground terminal GND. The interference source X is connected in parallel with the Y capacitor Cy. One end of the parasitic capacitor Cs is electrically connected to one end of the Y capacitor Cy, and the other end of the parasitic capacitor Cs is electrically connected to one end of the EMC sampling resistor Re. The other end of the EMC sampling resistor Re is also electrically connected to the ground terminal GND. The parasitic capacitor Cs includes parasitic capacitors from the primary winding to the secondary winding, as well as parasitic capacitors from the primary winding to the ground terminal and from the secondary winding to the ground terminal. The combined capacitance of these parasitic capacitors is much smaller than the capacitance of the Y capacitor. Given a fixed interference source, the smaller the capacitance of the Y capacitor Cy, the smaller the current in the EMC sampling resistor Re, and the better the EMC performance.

[0043] Based on this, some embodiments of the present invention provide an air conditioner. For example... Figure 2 As shown, the air conditioner 1000 includes a base plate 200; the base plate 200 includes an electromagnetic compatibility module 100; the electromagnetic compatibility module 100 includes a transformer 1.

[0044] To facilitate understanding, we will first provide a brief introduction and explanation of some terms or basic concepts of technology involved in the embodiments of the present invention.

[0045] Electromagnetic compatibility (EMC) refers to the ability of a device or system to operate in its electromagnetic environment without causing unacceptable electromagnetic interference to any other device in that environment.

[0046] Y capacitors are a type of ampere capacitor (Safety Fixed capacitor) used to suppress common-mode interference. Y capacitors do not pose a risk of electric shock after capacitor failure.

[0047] Parasitic capacitance is a distributed capacitance found between wires, between coils and the housing, and between certain components. In addition to the capacitance between the plates, sensors also have capacitive connections between the plates and surrounding objects (various components and even the human body); this capacitance is also called parasitic capacitance. It not only alters the capacitance of the capacitive sensor, but also, because the sensor's own capacitance is very small, the parasitic capacitance is extremely unstable, leading to unstable sensor characteristics and causing serious interference.

[0048] The Line Impedance Stabilization Network (LISN) is an important auxiliary device in electromagnetic compatibility testing of power systems. It isolates electromagnetic interference, provides stable test impedance, and acts as a filter.

[0049] like Figure 3 As shown, Figure 3 A simplified circuit diagram of the line impedance stabilization network is provided. The circuit diagram includes: line impedance stabilization network 2, interference source X, Y capacitor Cy, total distributed capacitance Ca and ground terminal EARTH; line impedance stabilization network 2 includes: a first resistor R1 and a second resistor R2. The first resistor R1 is configured on the live wire L and the second resistor R2 is configured on the neutral wire N.

[0050] The Y capacitor Cy is connected in parallel with the interference source X. The live wire and neutral wire of the above-mentioned line impedance stabilization network 2 are electrically connected to one end of the interference source X. The other end of the interference source is electrically connected to one end of the total distributed capacitor Ca. The other end of the total distributed capacitor Ca is electrically connected to the ground terminal EARTH. One end of the line impedance stabilization network 2 is electrically connected to the ground terminal EARTH.

[0051] Among them, the line impedance stabilization network 2 is configured to prevent external noise (in the public AC power grid) from entering the product through the AC power line and superimposing on the conducted emission of the measurement, thereby interfering with the measurement, similar to the shielding room in the radiated emission measurement.

[0052] The aforementioned line impedance stabilization network 2 is also configured to ensure that the AC impedance seen from the AC power grid is the same: providing a stable and consistent impedance (50Ω) between the phase and ground wires of the product, and between the neutral and ground wires, throughout the entire test frequency from one site to another, i.e., the resistance values ​​of the first resistor R1 and the second resistor R2 are both 50Ω.

[0053] like Figure 4A As shown, the transformer in the air conditioner substrate includes a magnetic core 12, a primary winding Np and a secondary winding Ns, wherein the primary winding Np is wrapped around the magnetic core 12, the secondary winding Ns is wrapped around the magnetic core 12, and the secondary winding Ns is located outside the primary winding Np.

[0054] Reference Figure 4B Without the first shielding winding Nc1 and the second shielding winding Nc2, the interference current of transformer 1 is the first interference current isg of the primary winding Np to the secondary winding Ns and the second interference current icg of the magnetic core 12 to the ground terminal EARTH. That is, the total interference current I... 总 It is the sum of the first interference current isg and the second interference current icg, i.e., I 总 =isg+icg.

[0055] like Figure 4B As shown, Figure 4B This is a circuit diagram of a transformer 1 provided in an embodiment of the present invention. The transformer 1 includes: a magnetic core 12, a primary winding Np and a secondary winding Ns; the primary winding Np is wound around the magnetic core 12, the secondary winding Ns is wound around the magnetic core 12, and the secondary winding Ns is located outside the primary winding Np.

[0056] The transformer 1 also includes: a first shielding winding Nc1 and / or a second shielding winding Nc2; the first shielding winding Nc1 is located between the magnetic core 12 and the primary winding Np, and the second shielding winding Nc2 is located between the primary winding Np and the secondary winding Ns; the winding method of the first shielding winding Nc1 and the primary winding Np is opposite.

[0057] In this process, the primary winding Np generates a first displacement current to the first shielding winding, and the magnetic core 12 generates a second displacement current to the first shielding winding. The directions of the first displacement current and the second displacement current are opposite.

[0058] The primary winding Np generates a third displacement current on the second shielding winding, and the secondary winding Ns generates a fourth displacement current on the second shielding winding; the third displacement current and the fourth displacement current are in opposite directions.

[0059] like Figure 4B As shown, the primary winding Np includes a first primary winding Np1 and a second primary winding Np2. The first primary winding Np1 and the second primary winding Np2 are wrapped around the magnetic core 12, and the second primary winding Np2 is located outside the first primary winding Np1. The first shielding winding Nc1 is located between the magnetic core 12 and the first primary winding Np1, and the second shielding winding is located between the second primary winding Np2 and the secondary winding Ns.

[0060] The following details the specific working process between the windings in transformer 1.

[0061] like Figure 5 As shown, Figure 5 This invention provides a circuit diagram for windings with the same number of turns, according to some embodiments of the present invention. The circuit diagram includes: a primary winding Np, a secondary winding Ns, and a coupling capacitance Cps between the primary winding Np and the secondary winding Ns. The coupling capacitance Cps is also the parasitic capacitance Cps of the primary winding Np to the secondary winding Ns of transformer 1.

[0062] In some embodiments, the primary winding Np and the secondary winding Ns have the same number of turns, both being 100 turns. During the operation of transformer 1, the voltage of the primary winding Np rises from 0V to 100V, and the voltage of the secondary winding Ns also rises from 0V to 100V. Since the voltages of the two windings are equal, no potential difference is generated, and therefore no current is generated; that is, the currents ips and isp flowing through capacitor Cps are 0. In other words, there is no displacement current when the primary winding Np and the secondary winding Ns have the same number of turns.

[0063] like Figure 6 As shown, Figure 6 This invention provides a circuit diagram for windings with different numbers of turns in some embodiments. The circuit diagram includes: a primary winding Np, a secondary winding Ns, a coupling capacitor Cps between the primary winding Np and the secondary winding Ns, and a coupling capacitor Csg between the secondary winding Ns and the ground terminal EARTH. Simultaneously, the coupling capacitor Cps is also the parasitic capacitance Cps of the primary winding Np to the secondary winding Ns of transformer 1, and the coupling capacitor Csg is also the parasitic capacitance Csg of the secondary winding Ns to the ground terminal EARTH of transformer 1.

[0064] In some embodiments, the primary winding Np has 100 turns and the secondary winding Ns has 10 turns. During the operation of transformer 1, the voltage of the primary winding Np rises from 0V to 100V, and the voltage of the secondary winding Ns rises from 0V to 10V. The potential difference between the primary winding Np and the secondary winding Ns generates a displacement current ips. This displacement current ips flows to the ground terminal EARTH through the parasitic capacitance Csg. The displacement current flowing from the secondary winding Ns to the ground terminal EARTH through the parasitic capacitance Csg is isg, i.e., isg = ips > 0A.

[0065] like Figure 7 As shown, Figure 7 This is a circuit diagram of an auxiliary winding provided in an embodiment of the present invention. The circuit diagram includes: a primary winding Np, a secondary winding Ns, a coupling capacitor Cps between the primary winding Np and the secondary winding Ns, a coupling capacitor Csg between the secondary winding Ns and the ground terminal EARTH, and a coupling capacitor Cbs between the auxiliary winding Nb and the secondary winding Ns. Simultaneously, the coupling capacitor Cps is also the parasitic capacitance Cps of the primary winding Np to the secondary winding Ns of transformer 1, the coupling capacitor Csg is also the parasitic capacitance Csg of the secondary winding Ns to the ground terminal EARTH of transformer 1, and the coupling capacitor Cbs is also the parasitic capacitance Cbs of the auxiliary winding Nb to the secondary winding Ns of transformer 1.

[0066] In some embodiments, the primary winding Np has 100 turns, the secondary winding Ns has 10 turns, and the auxiliary winding Nb has 9 turns. During the operation of transformer 1, the voltage of the primary winding Np rises from 0V to 100V, the voltage of the secondary winding Ns rises from 0V to 10V, and the voltage of the auxiliary winding Nb rises from 0V to 9V. The potential difference between the primary winding Np and the secondary winding Ns generates a displacement current ips, which flows through the parasitic capacitance Csg to the ground terminal EARTH. The displacement current ips flowing from the secondary winding Ns through the parasitic capacitance Csg to the ground terminal EARTH is isg.

[0067] Because the voltage of the auxiliary winding Nb is lower than that of the secondary winding Ns, the potential difference between the auxiliary and secondary windings Ns generates a displacement current ibs flowing from the secondary winding Ns to the auxiliary winding. This displacement current ips flows in the opposite direction to the primary winding Nb, i.e., ibs < 0 A, ips > 0 A. If ips = -ibs, then isg = 0 A, and in this case, the interference of the primary winding Np on the secondary winding Ns is zero.

[0068] like Figure 8 As shown, Figure 8 This invention provides a circuit diagram for shielding a magnetic core 12 to ground. The circuit diagram includes: a primary winding Np, a secondary winding Ns, a coupling capacitor Cpc between the primary winding Np and the magnetic core 12, a coupling capacitor Ccg between the magnetic core 12 and the ground terminal EARTH, and a coupling capacitor Ccc between the shielding winding Nc and the magnetic core 12. Simultaneously, the coupling capacitor Cpc is also the parasitic capacitance Cpc of the primary winding Np of the transformer 1 to the magnetic core 12, the coupling capacitor Ccg is also the parasitic capacitance Ccg of the magnetic core 12 of the transformer 1 to the ground terminal EARTH, and the coupling capacitor Ccc is also the parasitic capacitance Ccc of the shielding winding Nc of the transformer 1 to the magnetic core 12.

[0069] In some embodiments, the primary winding Np has 100 turns, the shielding winding Nc has 25 turns, and the magnetic core 12 can be considered to have no coil. Furthermore, the shielding winding Nc is wound in the opposite way to the primary winding Np, and the number of turns in the shielding winding Nc can be considered to be -25.

[0070] During the operation of transformer 1, the voltage of the primary winding Np rises from 0V to 100V, the voltage of the shielding winding drops from 0V to -25V, and the voltage of the magnetic core 12 can be considered as 0V. The potential difference between the primary winding Np and the magnetic core 12 generates a displacement current ipc, and the displacement current ipc > 0A. This displacement current ipc flows to the ground terminal EARTH through the parasitic capacitance Ccg. The displacement current from the magnetic core 12 through the parasitic capacitance Ccg to the ground terminal EARTH is icg. The potential difference between the shielding winding Nc and the magnetic core 12 generates a displacement current icc. Since the voltage of the shielding winding Nc is -25V and the voltage of the magnetic core 12 is 0V, the current direction of the displacement current icc is from the magnetic core 12 to the shielding winding Nc, that is, the displacement current icc < 0A.

[0071] When icg = ipc + icc = 0A, i.e., ipc = -icc, the displacement current of magnetic core 12 to ground is zero. In other words, the interference of magnetic core 12 to ground is zero.

[0072] It should be noted that the above Figures 5-8 The upper part refers to the number of turns in the winding.

[0073] In summary, transformer 1 can reduce the electromagnetic interference of the primary winding Np to the secondary winding Ns by adding an auxiliary winding Nb, and transformer 1 can also reduce the electromagnetic interference of the magnetic core 12 to the ground by adding a shielding winding Nc.

[0074] As Figure 4B As shown, Figure 4B The first shielding winding Nc1 in the circuit diagram is equivalent to the above Figure 8 The shielding winding, the second shielding winding Nc2 is equivalent to the above. Figure 7 Auxiliary winding.

[0075] Specifically, the first shielding winding Nc1 has fewer turns than the primary winding Np; the second shielding winding Nc2 has fewer turns than the secondary winding Ns, and the second shielding winding Nc2 has fewer turns than the first shielding winding Nc1. In other words, the secondary winding Ns has fewer turns than the primary winding Np.

[0076] In some embodiments, the number of turns of the first shielding winding Nc1 is less than 1 / 4 of the number of turns of the primary winding Np; the number of turns of the second shielding winding Nc2 is 1 / 2 of the number of turns of the first shielding winding Nc1.

[0077] like Figure 4BAs shown, in some embodiments, the first primary winding Np1 has 36 turns, the second primary winding Np2 has 36 turns, the secondary winding Ns has 12 turns, the first shielding winding Nc1 has 14 turns, and the second shielding winding Nc2 has 7 turns. This satisfies the condition that the number of turns in the first shielding winding Nc1 is less than 1 / 4 of the number of turns in the primary winding Np2, and the number of turns in the second shielding winding Nc2 is 1 / 2 of the number of turns in the first shielding winding Nc1.

[0078] During the operation of transformer 1, the voltage of the first primary winding Np1 rises from 0V to 36V, the voltage of the second primary winding Np2 rises from 0V to 36V, the voltage of the secondary winding Ns rises from 0V to 12V, the voltage of the first shielding winding Nc1 drops from 0V to -14V, the voltage of the second shielding winding Nc2 rises from 0V to 7V, and the voltage of the magnetic core 12 can be considered as 0V.

[0079] The first primary winding Np1 generates a first displacement current iph1 on the first shielding winding, and the magnetic core 12 generates a second displacement current ich1 on the first shielding winding. The directions of the first displacement current iph1 and the second displacement current ich1 are opposite.

[0080] The second primary winding Np2 generates a third displacement current iph2 on the second shielding winding, and the secondary winding Ns generates a fourth displacement current ich2 on the second shielding winding; the third displacement current iph2 and the fourth displacement current ich2 are in opposite directions.

[0081] like Figure 10 As shown, without the first shielding winding Nc1 and the second shielding winding Nc2, the interference current of transformer 1 consists of the first interference current isg from the primary winding Np to the secondary winding Ns and the second interference current icg from the magnetic core 12 to the ground terminal EARTH. That is, the total interference current I... 总 It is the sum of the first interference current isg and the second interference current icg, i.e., I 总 =isg+icg.

[0082] When the first shielding winding Nc1 and the second shielding winding Nc2 are added to transformer 1, the first interference current isg will be partially canceled by the fourth displacement current ich2, and the second interference current icg will be partially canceled by the second displacement current ich1, that isg = iph2 - ich2, icg = iph1 - ich1.

[0083] In other words, the displacement current of the secondary winding Ns relative to the EARTH terminal is isg = iph2 - ich2, which is much smaller than the displacement current iph2 before the second shielding winding Nc2 was removed. Therefore, the displacement current of the primary winding Np relative to the secondary winding Ns and to ground is very small, resulting in relatively low electromagnetic interference. The displacement current of the magnetic core 12 relative to the EARTH terminal is icg = iph1 - ich1, which is much smaller than the displacement current iph1 before the first shielding winding Nc1 was removed. Therefore, the displacement current of the magnetic core 12 relative to the EARTH terminal is very small, resulting in relatively low electromagnetic interference. That is, I 总 =isg+icg=iph2-ich2+iph1-ich1. I 总 As the frequency decreases, electromagnetic interference also decreases.

[0084] In some embodiments, transformer 1 can be modified by adding only the first shielding winding Nc1. In this case, the displacement current of the magnetic core 12 relative to the ground terminal EARTH is icg = iph1 - ich1, which is much smaller than the displacement current iph1 without the first shielding winding Nc1. Therefore, the displacement current of the magnetic core 12 relative to the ground terminal EARTH is very small, and the electromagnetic interference is relatively small. That is, I 总 =isg+icg=isg+iph1-ich1. I 总 As the frequency decreases, electromagnetic interference also decreases.

[0085] In some embodiments, transformer 1 can be modified by adding only a second shielding winding Nc2. In this case, the displacement current of the secondary winding Ns relative to the ground terminal EARTH is isg = iph2 - ich2, which is much smaller than the displacement current iph2 without the second shielding winding Nc2. Therefore, the displacement current of the primary winding Np relative to the secondary winding Ns and to ground is very small, resulting in relatively low electromagnetic interference. That is, I 总 =isg + icg = iph2 - ich2 + icg. I is always decreasing, so electromagnetic interference is also decreasing.

[0086] It should be noted that in some embodiments, the first displacement current iph1 and the second displacement current ich1 may not be equal, and the third displacement current iph2 and the fourth displacement current ich2 may not be equal. This is because the system efficiency would be low if they were completely canceled out. Since the output power is constant, there will be losses as long as displacement current is generated, and the larger the displacement current, the greater the losses. Therefore, the displacement current does not need to be equal to the interference current; it only needs to meet the test requirements.

[0087] In some embodiments, the first shielding winding Nc1 is tightly wound, and the second shielding winding Nc2 is also tightly wound. However, in some special cases, the first shielding winding Nc1 and the second shielding winding Nc2 need to be loosely wound.

[0088] like Figure 9 As shown, Figure 9 This is a schematic diagram of a transformer 1 provided in an embodiment of the present invention. The transformer 1 includes: a frame 11, pins 13, a first shielding winding Nc1, a second shielding winding Nc2, a first primary winding Np1, a second primary winding Np2, a first secondary winding Ns1, a second secondary winding Ns2, insulating tape, and retaining tape. The frame 11 is configured to support the windings, and together with the pins 13, forms a complete support, allowing the transformer's input and output lines to be easily soldered onto the pins 13.

[0089] like Figure 9 As shown, the left side of the winding has 6 mm of retaining tape, and the right side of the winding has 3 mm of retaining tape. Specifically, two turns of insulating tape are wrapped between the first shielding winding Nc1 and the first primary winding Np1; one turn of insulating tape is wrapped between the first primary winding Np1 and the second primary winding Np2; one turn of insulating tape is wrapped between the second primary winding Np2 and the second shielding winding Nc2; three turns of insulating tape are wrapped between the second shielding winding Nc2 and the secondary winding Ns; one turn of insulating tape is wrapped between the first secondary winding Ns1 and the second secondary winding Ns2; and three turns of insulating tape are wrapped around the outermost edge of the secondary winding.

[0090] In some embodiments, the above-mentioned retaining wall tape is made by coating acrylic pressure-sensitive adhesive or rubber-plastic pressure-sensitive adhesive onto a polyester film composite nonwoven fabric substrate, and has good pressure resistance, high temperature resistance, solvent resistance and the inherent adhesive properties of pressure-sensitive adhesive.

[0091] In some embodiments, the insulating tape is configured to prevent the transformer frame edge from scratching the transformer winding conductors; at the same time, the insulating tape is also configured to increase the winding density, enhance the stability of the winding, enhance the insulation strength between windings, and enhance heat dissipation.

[0092] like Figure 10 As shown, Figure 10 This is a circuit diagram for electromagnetic compatibility provided in an embodiment of the present invention. (Refer to...) Figure 4B The electromagnetic compatibility module 100 further includes: a first voltage terminal Vin, a second voltage terminal Vo, a primary ground terminal GND1, and a secondary ground terminal GND2; the first end of the primary winding Np is electrically connected to the first voltage terminal Vin, and the second end of the primary winding Np is electrically connected to the primary ground terminal GND1; the first end of the secondary winding Ns is electrically connected to the second voltage terminal Vo, and the second end of the secondary winding Ns is electrically connected to the secondary ground terminal GND2.

[0093] The aforementioned electromagnetic compatibility module 100 also includes a Y capacitor Cy and a line impedance stabilization network 2, wherein the Y capacitor Cy is located between the primary ground terminal GND1 and the secondary ground terminal GND2.

[0094] The line impedance stabilization network 2 includes: a first stabilizing capacitor C1, a second stabilizing capacitor C2, a third stabilizing capacitor C3, a fourth stabilizing capacitor C4, a first inductor L1, a second inductor L2, a first resistor R1, a second resistor R2, and a ground terminal EARTH.

[0095] The first terminal of the first stabilizing capacitor C1 is electrically connected to the first inductor L1. The second terminal of the first stabilizing capacitor C1 is electrically connected to the first terminal of the third stabilizing capacitor C3. The first terminal of the second stabilizing capacitor C2 is electrically connected to the second terminal of the first inductor L1. The second terminal of the second stabilizing capacitor C2 is electrically connected to the first terminal of the first resistor R1. The second terminal of the first resistor R1 is electrically connected to the first terminal of the second resistor R2. The second terminal of the second resistor R2 is electrically connected to the first terminal of the fourth stabilizing capacitor C4. The second terminal of the third stabilizing capacitor C3 is electrically connected to the first terminal of the second inductor L2. The second terminal of the fourth stabilizing capacitor C4 is electrically connected to the second terminal of the second inductor L2. The second terminal of the first stabilizing capacitor C1 is electrically connected to the ground terminal. The second terminal of the first resistor R1 is electrically connected to the ground terminal.

[0096] It should be noted that the first resistor R1 and the second resistor R2 mentioned above are electromagnetic compatibility sampling resistors, and the first resistor R1 and the second resistor R2 are connected in parallel. The resistance values ​​of the first resistor R1 and the second resistor R2 are both 50 ohms. Therefore, the common mode interference voltage of the transformer Vcm = 25 × (icg + isg).

[0097] The electromagnetic compatibility module 100 also includes: a rectifier circuit 3, which includes: four identical diodes D; the first end of the rectifier circuit 3 is electrically connected to the first end of the second stabilizing capacitor C2, the second end of the rectifier circuit 3 is electrically connected to the first end of the primary winding Np, the third end of the rectifier circuit 3 is electrically connected to the second end of the fourth stabilizing capacitor C4, and the fourth end of the rectifier circuit 3 is electrically connected to the primary ground terminal GND1.

[0098] In some embodiments, the rectifier circuit 3 is configured to convert alternating current into direct current.

[0099] like Figure 10 As shown, transformer 1 also includes: diode D1 and first electrolytic capacitor Cin1. The positive terminal of diode D1 is electrically connected to the first terminal of secondary winding Ns, the negative terminal of diode D1 is electrically connected to the second voltage terminal Vo, the negative terminal of diode D1 is electrically connected to the positive terminal of first electrolytic capacitor Cin1, and the negative terminal of first electrolytic capacitor Cin1 is electrically connected to the second terminal of secondary winding Ns.

[0100] The electromagnetic compatibility module 100 also includes: a second electrolytic capacitor Cin2, the first end of which is electrically connected to the first end of the primary winding Np, and the second end of which is electrically connected to the primary grounding terminal GND1.

[0101] In some embodiments, the electromagnetic compatibility module 100 further includes: a switching transistor Q, the first terminal of which is electrically connected to the primary winding Np, and the second terminal of which is electrically connected to the primary ground terminal GND1.

[0102] like Figure 11A and Figure 11B As shown, where Figure 11A and Figure 11B The waveform resembling a square wave represents the limit value for electromagnetic compatibility (EMC). If the EMC waveform is above or coincides with the limit value waveform, the test fails; if the EMC waveform is below the limit value waveform, the test succeeds.

[0103] like Figure 11A As shown, when there is a Y capacitor, the waveform of the electromagnetic compatibility test report of the electromagnetic compatibility module 100 is below the limit value waveform, and the test is successful.

[0104] like Figure 11B As shown, when there is no Y capacitor, the waveform of the electromagnetic compatibility module 100 test report is above the limit value waveform, and the test fails.

[0105] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An air conditioner, characterized in that, include: substrate; The substrate includes: an electromagnetic compatibility module; The electromagnetic compatibility module includes: a transformer; The transformer includes: a magnetic core, a primary winding, and a secondary winding; the primary winding is wound around the magnetic core, the secondary winding is wound around the magnetic core, and the secondary winding is located outside the primary winding; The transformer further includes: a first shielding winding and / or a second shielding winding; the first shielding winding is located between the magnetic core and the primary winding, and the second shielding winding is located between the primary winding and the secondary winding; the winding method of the first shielding winding and the primary winding are opposite. The primary winding includes a first primary winding and a second primary winding, which are wound around the magnetic core, with the second primary winding located outside the first primary winding; the first shielding winding is located between the magnetic core and the first primary winding, and the second shielding winding is located between the second primary winding and the secondary winding. The primary winding generates a first displacement current to the first shielding winding, and the magnetic core generates a second displacement current to the first shielding winding. The directions of the first displacement current and the second displacement current are opposite. The primary winding generates a third displacement current to the second shielding winding, and the secondary winding generates a fourth displacement current to the second shielding winding; the third displacement current and the fourth displacement current are in opposite directions.

2. The air conditioner according to claim 1, characterized in that, The number of turns in the first shielding winding is less than the number of turns in the primary winding; The number of turns in the second shielding winding is less than the number of turns in the secondary winding, and the number of turns in the second shielding winding is less than the number of turns in the first shielding winding.

3. The air conditioner according to claim 2, characterized in that, The number of turns in the first shielding winding is less than 1 / 4 of the number of turns in the primary winding; the number of turns in the second shielding winding is 1 / 2 of the number of turns in the first shielding winding.

4. The air conditioner according to claim 1, characterized in that, The electromagnetic compatibility module further includes: a first voltage terminal, a second voltage terminal, a primary ground terminal, and a secondary ground terminal; The first end of the primary winding is electrically connected to the first voltage terminal, and the second end of the primary winding is electrically connected to the primary ground terminal; The first end of the secondary winding is electrically connected to the second voltage terminal, and the second end of the secondary winding is electrically connected to the secondary ground terminal.

5. The air conditioner according to claim 4, characterized in that, The electromagnetic compatibility module further includes a Y capacitor, which is located between the primary ground terminal and the secondary ground terminal.

6. The air conditioner according to claim 5, characterized in that, The electromagnetic compatibility module further includes: a line impedance stabilization network, which includes: a first stabilizing capacitor, a second stabilizing capacitor, a third stabilizing capacitor, a fourth stabilizing capacitor, a first inductor, a second inductor, a first resistor, a second resistor, and a ground terminal; The first terminal of the first stabilizing capacitor is electrically connected to the first inductor; the second terminal of the first stabilizing capacitor is electrically connected to the first terminal of the third stabilizing capacitor; the first terminal of the second stabilizing capacitor is electrically connected to the second terminal of the first inductor; the second terminal of the second stabilizing capacitor is electrically connected to the first terminal of the first resistor; the second terminal of the first resistor is electrically connected to the first terminal of the second resistor; the second terminal of the second resistor is electrically connected to the first terminal of the fourth stabilizing capacitor; the second terminal of the third stabilizing capacitor is electrically connected to the first terminal of the second inductor; the second terminal of the fourth stabilizing capacitor is electrically connected to the second terminal of the second inductor; the second terminal of the first stabilizing capacitor is electrically connected to the ground terminal; and the second terminal of the first resistor is electrically connected to the ground terminal.

7. The air conditioner according to claim 6, characterized in that, The electromagnetic compatibility module further includes a rectifier circuit, which comprises four identical diodes. The first terminal of the rectifier circuit is electrically connected to the first terminal of the second stabilizing capacitor, the second terminal of the rectifier circuit is electrically connected to the first terminal of the primary winding, the third terminal of the rectifier circuit is electrically connected to the second terminal of the fourth stabilizing capacitor, and the fourth terminal of the rectifier circuit is electrically connected to the primary ground terminal.

8. The air conditioner according to claim 7, characterized in that, The transformer further includes: a diode and a first electrolytic capacitor, wherein the positive terminal of the diode is electrically connected to the first end of the secondary winding, the negative terminal of the diode is electrically connected to the second voltage terminal, the negative terminal of the diode is electrically connected to the positive terminal of the first electrolytic capacitor, and the negative terminal of the first electrolytic capacitor is electrically connected to the second end of the secondary winding; The electromagnetic compatibility module further includes: a second electrolytic capacitor, the first end of which is electrically connected to the first end of the primary winding, and the second end of which is electrically connected to the primary grounding terminal.

9. The air conditioner according to claim 8, characterized in that, The electromagnetic compatibility module further includes a switching transistor, wherein the first terminal of the switching transistor is electrically connected to the primary winding, and the second terminal of the switching transistor is electrically connected to the primary ground terminal.

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