Air conditioner

Abstract

The invention provides an air conditioner, relates to the technical field of air conditioner driving, and aims to solve the problem that an IPM module is over-current when sampling voltage is lower than reference voltage. The air conditioner comprises an IPM module and an overcurrent protection trigger circuit. The over-current protection trigger circuit comprises a first end and a second end, and the first end and the second end of the over-current protection trigger circuit are electrically connected with the output end and the over-current protection end of the IPM module respectively. The IPM module is configured to trigger over-current protection when the voltage of the over-current protection end is greater than or equal to the reference voltage. The overcurrent protection trigger circuit comprises a sampling resistor, a first resistor, a second resistor and a third resistor, the sampling resistor is connected with the output end of the IPM module, the output end of the IPM module outputs a first current, and the first current flows through the sampling resistor. And the first resistor, the second resistor and the third resistor are configured to enable the voltage of the overcurrent protection end to be greater than or equal to the reference voltage under the condition that the value of the first current is greater than a preset overcurrent value by adjusting the resistance values of the first resistor, the second resistor and the third resistor.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioner driving, and in particular to an air conditioner. Background Art

[0002] An IPM module is often used in a driving circuit of an air conditioner. The IPM module has a reference voltage, and the reference voltage cooperates with an overcurrent detection circuit connected to the IPM module to detect whether the IPM module is overcurrent.

[0003] When the sampling voltage of the overcurrent detection circuit is greater than or equal to the reference voltage, it indicates that the IPM module is overcurrent and enters the overcurrent protection. However, there is a situation where the sampling voltage is lower than the reference voltage and the IPM module is overcurrent, but the IPM does not enter the overcurrent protection at this time. Therefore, there is a great safety hazard. The existing technology usually adopts adding an operational amplifier or a comparator circuit to solve this situation.

[0004] Adding an operational amplifier or a comparator circuit to solve the problem of overcurrent in the IPM module due to the sampling voltage being lower than the reference voltage increases the cost and the difficulty of maintenance. Summary of the invention

[0005] The embodiment of the present invention provides an air conditioner for solving the problem of overcurrent in an IPM module caused by a sampling voltage being lower than a reference voltage, and the air conditioner has a simple circuit, low cost and is easy to maintain.

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

[0007] The air conditioner provided by the present invention includes a compressor, the compressor includes a variable frequency drive circuit, and the variable frequency drive circuit includes an IPM module and an overcurrent protection trigger circuit. The overcurrent protection trigger circuit includes a first end and a second end, the first end of the overcurrent protection trigger circuit is electrically connected to the output end of the IPM module, and the second end of the overcurrent protection trigger circuit is electrically connected to the overcurrent protection end of the IPM module. The IPM module is configured to trigger overcurrent protection when the voltage at the overcurrent protection end is greater than or equal to a reference voltage. The overcurrent protection trigger circuit includes a sampling resistor, a first resistor, a second resistor, and a third resistor, the sampling resistor is connected to the output end of the IPM module, the output end of the IPM module outputs a first current, and the first current flows through the sampling resistor. The first resistor, the second resistor, and the third resistor are configured to adjust the resistance value of the first resistor, the resistance value of the second resistor, and the resistance value of the third resistor so that when the value of the first current is greater than a preset overcurrent value, the voltage at the overcurrent protection end is greater than or equal to the reference voltage.

[0008] The overcurrent protection of the IPM module will only be triggered when the voltage at the overcurrent protection terminal of the IPM module is greater than or equal to the reference voltage inside the IPM module. Since the voltage at the overcurrent protection terminal of the IPM module is less than the reference voltage inside the IPM module, but the IPM module should also be in the overcurrent protection situation, the present application adjusts the resistance value of the first resistor, the resistance value of the second resistor, and the resistance value of the third resistor so that when the value of the first current is greater than the preset overcurrent value, the voltage at the overcurrent protection terminal is greater than or equal to the reference voltage. The situation where the value of the first current is greater than the preset overcurrent value means that the voltage at the overcurrent protection terminal of the original IPM module is less than the reference voltage inside the IPM module, but the IPM module should also be in the overcurrent protection situation. The setting of the preset overcurrent value is the second insurance for the overcurrent protection of the IPM module, making the overcurrent protection of the IPM module more comprehensive and the variable frequency drive circuit safer and more stable.

[0009] As a possible implementation, the first end of the sampling resistor is electrically connected to the first end of the overcurrent protection trigger circuit, and the second end of the sampling resistor is electrically connected to the ground terminal. The first end of the first resistor is electrically connected to the first end of the overcurrent protection trigger circuit, the second end of the first resistor is electrically connected to the first end of the second resistor, the second end of the second resistor is electrically connected to the ground terminal, and the first end of the second resistor is also electrically connected to the second end of the overcurrent protection trigger circuit. The first end of the third resistor is electrically connected to the second end of the overcurrent protection trigger circuit, and the second end of the third resistor is electrically connected to the voltage terminal.

[0010] As a possible implementation manner, when the value of the first current is greater than the preset overcurrent value and the voltage of the overcurrent protection terminal is greater than or equal to the reference voltage, the resistance value of the first resistor, the resistance value of the second resistor and the resistance value of the third resistor satisfy:

[0011]

[0012] Wherein IS is the preset overcurrent value, A is the reference voltage, B is the voltage at the voltage end, R2 is the resistance value of the first resistor, R1 is the resistance value of the second resistor, R3 is the resistance value of the third resistor, and RS is the resistance value of the sampling resistor.

[0013] As a possible implementation, the overcurrent protection trigger circuit further includes a capacitor, wherein a first electrode of the capacitor is electrically connected to a first end of the second resistor, and a second electrode of the capacitor is electrically connected to a second end of the second resistor.

[0014] As a possible implementation manner, the voltage of the voltage terminal includes 5V.

[0015] As a possible implementation manner, the resistance value of the sampling resistor is smaller than the resistance value of the first resistor, the resistance value of the sampling resistor is smaller than the resistance value of the second resistor, and the resistance value of the sampling resistor is smaller than the resistance value of the third resistor.

[0016] As a possible implementation, the output end of the IPM includes a first output end, a second output end and a third output end. The first output end, the second output end and the third output end are all electrically connected to the first end of the overcurrent protection trigger circuit.

[0017] As a possible implementation manner, the IPM module triggering the overcurrent protection includes: the IPM module shutting down.

[0018] As a possible implementation manner, the first resistor, the second resistor, and the third resistor are adjustable resistors, and the sampling resistor is a fixed resistor.

[0019] As a possible implementation, the variable frequency drive circuit further includes a motor, and the motor includes a first terminal, a second terminal, and a third terminal. The IPM module further includes a first end, a second end, and a third end. The first terminal of the motor is electrically connected to the first end of the IPM module, the second terminal of the motor is electrically connected to the second end of the IPM module, and the third terminal of the motor is electrically connected to the third end of the IPM module. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0021] Figure 1 A schematic diagram of an air conditioner provided in an embodiment of the present application;

[0022] Figure 2 A schematic diagram of an air conditioner composition provided in an embodiment of the present application;

[0023] Figure 3 A schematic diagram illustrating an air conditioning refrigeration process provided in an embodiment of the present application;

[0024] Figure 4 A schematic diagram of a variable frequency drive circuit for a compressor provided in an embodiment of the present application;

[0025] Figure 5 A schematic diagram of an overcurrent protection trigger circuit provided in an embodiment of the present application;

[0026] Figure 6 An equivalent schematic diagram of an excitation source in a variable frequency drive circuit provided in an embodiment of the present application;

[0027] Figure 7 A circuit diagram provided in an embodiment of the present application when a current source equivalent to a first current outputted from an output terminal of an IPM module is set to zero;

[0028] Figure 8An equivalent schematic diagram of the two ends of the sampling resistor when the equivalent voltage source in the overcurrent protection trigger circuit is reset to zero, provided in an embodiment of the present application;

[0029] Fig. 9 A circuit diagram of an equivalent voltage source in an overcurrent protection trigger circuit provided in an embodiment of the present application when it is set to zero;

[0030] Fig.10 A schematic diagram of another overcurrent protection trigger circuit provided in an embodiment of the present application;

[0031] Fig.11 A resistor classification schematic diagram provided in an embodiment of the present application;

[0032] Fig.12 A schematic diagram of another overcurrent protection trigger circuit provided in an embodiment of the present application;

[0033] Fig.13 A schematic diagram of an IPM module output terminal provided in an embodiment of the present application;

[0034] Fig.14 A schematic diagram of the composition of a variable frequency drive circuit provided in an embodiment of the present application;

[0035] Fig.15 A schematic diagram of a motor terminal provided in an embodiment of the present application;

[0036] Fig.16 A schematic diagram of the connection between a motor and an IPM module provided in an embodiment of the present application. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0039] The terms "first" and "second" are used for descriptive purposes only and should not 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.

[0040] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection. 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 the pipeline, the "connected" and "connection" used in the present invention have the meaning of conduction. The specific meaning needs to be understood in conjunction with the context.

[0041] In the embodiments of the present invention, words such as "exemplary" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present invention 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.

[0042] With the continuous advancement of technology and the improvement of people's living standards, air conditioners are becoming more and more popular. Figure 1 As shown, Figure 1 Schematic diagram of an air conditioner provided in an embodiment of the present application. Air conditioner 100 is a device for adjusting and controlling parameters such as temperature, humidity, and flow rate of ambient air in a building or structure. Air conditioner 100 can be a cabinet air conditioner, a wall mounted air conditioner, a central air conditioner, etc. Figure 1 Only a wall mounted air conditioner is used for illustration, and this application does not impose any special restrictions on the specific form of the air conditioner.

[0043] In some embodiments, the air conditioner comprises Figure 2 See Figure 2 The air conditioner 100 includes a compressor 1 , a condenser 2 and an evaporator 3 .

[0044] Combination Figure 3 , explain the refrigeration process of air conditioning, Figure 3 The arrows shown in the figure represent the direction of movement of the refrigerant. Compressor 1 is a driven fluid machine that converts low-pressure gas into high-pressure gas. It is the heart of the air conditioning refrigeration system. The suction pipe of compressor 1 inhales low-temperature and low-pressure refrigerant gas. After the motor drives the piston to compress the refrigerant, it discharges high-temperature and high-pressure refrigerant gas to the exhaust pipe, providing power for the refrigeration cycle of the air conditioner.

[0045] The high-temperature and high-pressure refrigerant gas discharged from the exhaust pipe of the compressor 1 flows to the condenser 2. The condenser 2 is a device that releases heat and can condense the high-temperature and high-pressure refrigerant gas, converting the refrigerant gas into medium-temperature and high-pressure condensate. After the pressure is reduced and the temperature is lowered by the throttle valve, it becomes a low-temperature and low-pressure condensate and is discharged to the evaporator 3 through the discharge pipe. The throttle valve can also achieve the function of regulating different indoor temperatures by controlling the flow rate of the condensate.

[0046] The evaporator 3 can evaporate the condensate, absorbing a large amount of heat during the evaporation process, thereby causing the indoor temperature to drop. During the evaporation process, the condensate turns into gas again and is discharged to the compressor 1, thus realizing a refrigeration cycle from compression to condensation and then to evaporation.

[0047] With the further enhancement of productivity, variable frequency air conditioners have been updated and iterated on the basis of conventional air conditioners. The difference between variable frequency air conditioners and conventional fixed frequency air conditioners is that variable frequency air conditioners no longer rely on the constant "on" and "off" of the compressor to adjust the indoor temperature, but achieve the purpose of temperature control by changing the speed of the compressor, which has the advantages of small room temperature fluctuations and low energy consumption.

[0048] For example, Figure 4 As shown, Figure 4 The figure shows the frequency conversion drive circuit composition of the compressor. Figure 4 The variable frequency drive circuit 10 includes an IPM module 11 and an overcurrent protection trigger circuit 12, wherein the overcurrent protection trigger circuit 12 includes a first end and a second end, and the IPM module 11 includes an output end and an overcurrent protection end. The first end of the overcurrent protection trigger circuit 12 is electrically connected to the output end of the IPM module 11, and the second end of the overcurrent protection trigger circuit 12 is electrically connected to the overcurrent protection end of the IPM module 11.

[0049] IPM (Intelligent Power Module) module, also known as intelligent power module, has integrated power switch devices and sub-circuits with various functions. For example, IPM often uses insulated gate bipolar transistor (IGBT) as power switch device, and has an integrated structure of current sensor and drive circuit. IPM module is widely used in the field of variable frequency household appliances due to its high reliability and low power consumption.

[0050] The overcurrent protection trigger circuit is designed to prevent the occurrence of instantaneous current surges in the variable frequency drive circuit due to device short circuits, abnormal motor operation, etc. In such cases, the IPM module is easily burned out. Therefore, an overcurrent protection trigger circuit is added between the output end and the overcurrent protection end of the IPM module to monitor the current output by the output end of the IPM module. When an instantaneous current surge occurs, the IPM module enters overcurrent protection.

[0051] The IPM module has an internal reference voltage when it leaves the factory. This reference voltage is a fixed value and serves as a standard for measuring whether the IPM module is in an overcurrent state. The overcurrent protection trigger circuit converts the current at the output end of the IPM module into a voltage, and outputs it to the overcurrent protection end of the IPM after voltage distribution inside the overcurrent protection trigger circuit. The IPM module compares the overcurrent protection end voltage with the internal reference voltage. When the overcurrent protection end voltage is greater than or equal to the internal reference voltage of the IPM module, it means that the IPM module is in an overcurrent state and needs to enter overcurrent protection. When the overcurrent protection end voltage is less than the internal reference voltage of the IPM module, it means that the IPM module is in a normal state.

[0052] For example, an overcurrent protection trigger circuit provided in an embodiment of the present application is as follows: Figure 5 See Figure 5 The overcurrent protection trigger circuit 12 includes a sampling resistor 121, a first resistor 122, a second resistor 123 and a third resistor 124. The sampling resistor 121 is connected to the output end of the IPM module 11. The output end of the IPM module 11 outputs a first current, and the first current flows through the sampling resistor 121. The first resistor 122, the second resistor 123 and the third resistor 124 are configured to adjust the resistance value of the first resistor 122, the resistance value of the second resistor 123 and the resistance value of the third resistor 124 so that when the value of the first current is greater than the preset overcurrent value, the voltage at the overcurrent protection end is greater than or equal to the reference voltage.

[0053] The voltage of the first current output from the output end of the IPM module 11 after flowing through the sampling resistor 121 is the sampling voltage. The sampling voltage is divided according to the resistance value of the first resistor 122, the resistance value of the second resistor 123 and the resistance value of the third resistor 124, and then transmitted to the overcurrent protection end of the IPM module 11 through the second end of the overcurrent protection trigger circuit 12.

[0054] The overcurrent protection of the IPM module will only be triggered when the voltage at the overcurrent protection terminal of the IPM module is greater than or equal to the reference voltage inside the IPM module. Since the voltage at the overcurrent protection terminal of the IPM module is lower than the reference voltage inside the IPM module, but the IPM module should also be in the overcurrent protection state, the present application adjusts the resistance value of the first resistor, the resistance value of the second resistor, and the resistance value of the third resistor so that when the value of the first current is greater than the preset overcurrent value, the voltage at the overcurrent protection terminal is greater than or equal to the reference voltage. This solves the problem that the IPM module version should enter the overcurrent protection state but cannot perform overcurrent protection because the voltage at the overcurrent protection terminal of the IPM module is lower than the reference voltage inside the IPM module. Compared with the prior art that requires adding an operational amplifier or a comparator circuit to solve the above problem, the circuit is simplified to a great extent and the cost is saved.

[0055] Reference Figure 5 , the specific connection relationship inside the overcurrent protection trigger circuit 12 is as follows: the first end of the sampling resistor 121 is electrically connected to the first end of the overcurrent protection trigger circuit 12, and the second end of the sampling resistor 121 is electrically connected to the ground terminal GND. The first end of the first resistor 122 is electrically connected to the first end of the overcurrent protection trigger circuit 12, the second end of the first resistor 122 is electrically connected to the first end of the second resistor 123, the second end of the second resistor 123 is electrically connected to the ground terminal GND, and the first end of the second resistor 123 is also electrically connected to the second end of the overcurrent protection trigger circuit 12. The first end of the third resistor 124 is electrically connected to the second end of the overcurrent protection trigger circuit 12, and the second end of the third resistor 124 is electrically connected to the voltage terminal VCC.

[0056] It should be noted that the resistance of the sampling resistor 121 is smaller than the resistance of the first resistor 122, the resistance of the sampling resistor 121 is smaller than the resistance of the second resistor 123, and the resistance of the sampling resistor 121 is smaller than the resistance of the third resistor 124. For example, the resistance of the sampling resistor 121 is 5 milliohms, the resistance of the first resistor 122 is 1000Ω, the resistance of the second resistor 123 is 100Ω, and the resistance of the third resistor 124 is 2000Ω.

[0057] As a possible implementation manner, the voltage of the voltage terminal VCC is 5V.

[0058] For the convenience of explanation, Figure 5The resistance value of the first resistor 122 is recorded as R2, the resistance value of the sampling resistor 121 is recorded as RS, the resistance value of the second resistor 123 is recorded as R1, the resistance value of the third resistor 124 is recorded as R3, the reference voltage of the IPM module 11 is recorded as A, the voltage of the voltage terminal VCC is recorded as B, the voltage of the overcurrent protection terminal of the IPM module 11 is recorded as Vt, the voltage of the first terminal of the overcurrent protection trigger circuit 12 is recorded as Vs, and the first current output by the output terminal of the IPM module 11 is recorded as Is.

[0059] According to the superposition theorem, the voltage at the overcurrent protection terminal is

[0060]

[0061] The superposition theorem is applicable to linear circuits with a unique solution. Its content is the response caused by the joint action of multiple excitation sources, that is, the voltage and current at each point in the circuit are equal to the sum of the responses caused by each excitation source acting alone (other excitation sources are set to zero). Figure 5 It can be seen that the components in the overcurrent protection trigger circuit 12: the sampling resistor 121, the first resistor 122, the second resistor 123 and the third resistor 124 are all linear devices, so the overcurrent protection trigger circuit 12 is a linear circuit, and the voltage Vs at the first end of the overcurrent protection trigger circuit 12 is unique, and there can only be one value at any time, so the applicability conditions of the superposition theorem are met.

[0062] For example, Figure 6 As shown, Figure 6 The equivalent excitation source in the variable frequency drive circuit is shown. Figure 6 , the voltage terminal VCC is an excitation source in the variable frequency drive circuit. Since the output terminal of the IPM module 11 is connected to the first terminal of the overcurrent protection trigger circuit 12, the first current Is output by the output terminal of the IPM module 11 is another excitation source in the variable frequency drive circuit. The voltage terminal VCC is equivalent to Figure 6 The voltage source shown in FIG. 1 is the voltage of the voltage source, the voltage of the voltage source is the voltage of the voltage terminal VCC, and the first current Is is equivalent to Figure 6 The current source in the current source is the magnitude of the first current Is.

[0063] As can be seen from the above, the resistance of the sampling resistor 121 is in the milliohm level, while the resistances of the first resistor 122, the second resistor 123 and the third resistor 124 are much greater than the resistance of the sampling resistor 121. Therefore, almost all of the first current Is flows through the sampling resistor 121, and since the first end of the sampling resistor 121 is electrically connected to the first end of the overcurrent protection trigger circuit, and the second end of the sampling resistor is electrically connected to the ground end, the voltage Vs at the first end of the overcurrent protection trigger circuit 121 is also the voltage at both ends of the sampling resistor 121.

[0064] According to the superposition theorem and combined Figure 7 , Figure 7 The circuit is shown when the current source equivalent to the first current Is outputted from the output terminal of the IPM module is set to zero. Figure 7 The second end of the sampling resistor 121 is electrically connected to the ground terminal GND, the first end of the sampling resistor 121 is electrically connected to the second end of the first resistor 122, the first end of the first resistor 122 is electrically connected to the first end of the second resistor 123, the second end of the second resistor 123 is electrically connected to the ground terminal GND, and the first end of the third resistor 124 is electrically connected to the first end of the second resistor 123.

[0065] The first resistor 122 is connected in series with the sampling resistor 121, then connected in parallel with the second resistor 123, and finally connected in series with the third resistor 124. The voltage source serves as an excitation source for the entire circuit, providing a voltage of VCC. Since the second end of the second resistor 123 is electrically connected to the ground terminal GND, and the second end of the sampling resistor 121 is electrically connected to the ground terminal GND, Figure 7 The potential at the node where the second end of the second resistor 123 is connected to the second end of the sampling resistor 121 is 0. When the current source equivalent to the first current Is output at the output end of the IPM module is set to zero, the voltage Vt1 at the overcurrent protection end of the IPM module is equivalent to the voltage source voltage VCC divided by the equivalent resistances of the first resistor 122, the second resistor 123 and the sampling resistor 121. Since the resistance of the sampling resistor 121 is negligible compared to the first resistor 122 and the second resistor 123, it can be obtained:

[0066]

[0067] For example, Figure 8 As shown, Figure 8 The equivalent diagram of the sampling resistor is shown when the equivalent voltage source in the overcurrent protection trigger circuit is reset to zero. Figure 8 Since the first current Is outputted from the output end of the IPM module 11 is relatively constant under normal circumstances, which is equivalent to a current source, the resistance of the sampling resistor 121 is relatively small, which is equivalent to the first current Is flowing through the sampling resistor 121. Therefore, the voltage across the sampling resistor 121 is also relatively constant, which is the product of Rs and Is. In the overcurrent protection trigger circuit, in order to study the magnitude of the voltage Vt at the overcurrent protection end of the IPM module 11, it can be equivalent to a voltage source, and the voltage VSS outputted by the voltage source is equal to Rs*Is.

[0068] Specifically, Fig. 9 As shown, Fig. 9 The circuit is shown when the equivalent voltage source in the overcurrent protection trigger circuit is set to zero. Fig. 9, since the voltage source equivalent to the voltage end of the overcurrent protection circuit is set to zero, it is equivalent to a short circuit of the voltage source, that is, it is equivalent to the third resistor 124 being connected in parallel to the two ends of the second resistor 123. Among them, the first end of the third resistor 124 is electrically connected to the first end of the second resistor 123, the second end of the third resistor 124 is electrically connected to the second end of the second resistor 123, and both are electrically connected to the ground terminal GND. The first end of the second resistor 123 is also electrically connected to the first end of the first resistor 122, the second end of the first resistor 122 is electrically connected to the positive electrode of the voltage source VSS, and the negative electrode of the voltage source VSS is electrically connected to the ground terminal GND.

[0069] The voltage source VSS supplies power to the entire overcurrent protection trigger circuit. When the equivalent voltage source in the overcurrent protection trigger circuit is set to zero, the overcurrent protection terminal voltage of the IPM module is Vt2. Since the first ends of the second resistor 123 and the third resistor 124 are both electrically connected to the overcurrent protection terminal of the IPM module, and the second ends of the second resistor 123 and the third resistor 124 are both electrically connected to the ground terminal GND, the overcurrent protection terminal voltage of the IPM module is Vt2, which is the voltage source voltage VSS divided between the second resistor 123 and the third resistor 124. It can be obtained that:

[0070]

[0071] The magnitude of the overcurrent protection terminal voltage Vt of the IPM module is the sum of the overcurrent protection terminal voltage Vt1 of the IPM module when the current source equivalent to the first current Is output at the output end of the IPM module is zero and the overcurrent protection terminal voltage Vt2 of the IPM module when the equivalent voltage source in the overcurrent protection trigger circuit is zero, that is, Vt = Vt1 + Vt2, that is,

[0072]

[0073] Since VSS = Rs*Is, substituting into the above formula we can get:

[0074]

[0075] When the voltage Vt at the overcurrent protection end of the IPM module is greater than or equal to the reference voltage of the IPM module, the overcurrent protection of the IPM module is triggered. That is to say, the minimum value for triggering the overcurrent protection of the IPM module is reflected in the voltage Vt at the overcurrent protection end of the IPM module, and the magnitude of Vt is equal to the magnitude of the reference voltage A.

[0076] According to the above formula, it can be seen that the value of the voltage Vt at the overcurrent protection end of the IPM module is related to the magnitude of the first current Is. It should be understood that the reason why the voltage Vt at the overcurrent protection end of the IPM does not reach the magnitude of the reference voltage A, but the IPM module is already in an overcurrent state is the magnitude of the first current. In other words, when the first current Is is large, the voltage of the first current Is output from the output end of the IPM module applied to the sampling resistor 121 is large, and the voltage Vt at the overcurrent protection end of the IPM module is a partial voltage division of the voltage applied to the sampling resistor 121. Therefore, Vt is mostly greater than or equal to the reference voltage, which can reflect that the IPM module enters an overcurrent state. When the first current Is is small, the voltage of the first current Is output from the output end of the IPM module applied to the sampling resistor 121 is small, and the voltage Vt at the overcurrent protection end of the IPM module is a partial voltage division of the voltage applied to the sampling resistor 121. Therefore, Vt is likely to be less than the reference voltage, but at this time the IPM module is already in an overcurrent state. Therefore, a preset overcurrent value IS is set.

[0077] It should be noted that the preset overcurrent value IS is an expected value set artificially, and the first current value Is is the first current value actually flowing out of the output end of the IPM module. When the first current Is is greater than the preset overcurrent value IS, it proves that the IPM module is already in an overcurrent state. In order to make the IPM module enter the overcurrent protection state, it is necessary to ensure that the overcurrent protection terminal voltage of the IPM module is greater than or equal to the reference voltage. Therefore, the resistance values ​​of the first resistor, the second resistor, and the third resistor can be obtained to satisfy:

[0078]

[0079] For example, if Fig.10 As shown, for example, the reference voltage of the IPM module is 0.5V, and the resistance value of the sampling resistor Rs is 0.01Ω. When the first current output from the output terminal of the IPM module is 30A, it indicates that the IPM module is in an overcurrent state and needs to trigger the overcurrent protection. In this case, the voltage flowing across the sampling resistor Rs is 0.3V (0.01*30), and the overcurrent protection terminal voltage of the IPM module is a portion of the voltage divided from the sampling resistor Rs, that is, Vt must be less than 0.3V, so it is impossible to reach the reference voltage of the IPM module, and the IPM module cannot trigger the overcurrent protection when it is already overcurrent.

[0080] The overcurrent protection trigger circuit provided in the present application adds a third resistor and a voltage terminal, and sets a preset overcurrent value IS in advance. By adjusting the resistance of the first resistor 122, the resistance of the second resistor 123, and the resistance of the third resistor 124, when the value of the first current is greater than the preset overcurrent value, the voltage at the overcurrent protection terminal is greater than or equal to the reference voltage. Take the case where the above-mentioned IPM module cannot trigger the overcurrent protection when there is already an overcurrent as an example. Since the first current output by the output terminal of the IPM module is 30A, it means that the IPM module is in an overcurrent state, then the size of the preset overcurrent value IS is 30A. Since it is known that the size of the preset overcurrent value IS is 30, the size of the reference voltage A is 0.5, the size of the sampling resistor is 0.01, and the voltage B of the voltage terminal VCC is 5, according to the formula:

[0081]

[0082] Multiple groups of resistance values ​​of R1, R2 and R3 can be obtained, for example, the first resistor R1 is 100Ω, the second resistor R2 is 1000Ω, and the third resistor R3 is 1800Ω. The first resistor, the second resistor and the third resistor are adjusted to the resistance values ​​of R1, R2 and R3, so that when the value of the first current is greater than the preset overcurrent value, the voltage of the overcurrent protection terminal is greater than or equal to the reference voltage, that is, the overcurrent protection can be triggered even when the original IPM module cannot trigger the overcurrent protection when the overcurrent is already triggered.

[0083] As a possible implementation, Fig.11 As shown, Fig.11 Showing the classification of resistors, refer to Fig.11 The first resistor 122, the second resistor 123, and the third resistor 124 are adjustable resistors, and the sampling resistor 121 is a fixed resistor. Exemplarily, the first resistor 122, the second resistor 123, and the third resistor 124 are sliding resistors and resistor boxes, and the present application does not limit their types.

[0084] By adjusting the resistance values ​​of the adjustable resistors: the first resistor, the second resistor and the third resistor, the desired preset overcurrent value can be obtained, thereby achieving overcurrent protection for the IPM module, which is more practical.

[0085] As a possible implementation, Fig.12 As shown, Fig.12 Another overcurrent protection trigger circuit provided by an embodiment of the present application is shown. Fig.12 The overcurrent protection trigger circuit 12 includes a sampling resistor 121 , a first resistor 122 , a second resistor 123 , a third resistor 124 and a capacitor 125 .

[0086] The first end of the sampling resistor 121 is electrically connected to the first end of the overcurrent protection trigger circuit 12, and the second end of the sampling resistor 121 is electrically connected to the ground terminal GND. The first end of the first resistor 122 is electrically connected to the first end of the overcurrent protection trigger circuit 12, the second end of the first resistor 122 is electrically connected to the first end of the second resistor 123, the second end of the second resistor 123 is electrically connected to the ground terminal GND, and the first end of the second resistor 123 is also electrically connected to the second end of the overcurrent protection trigger circuit 12. The first end of the third resistor 124 is electrically connected to the second end of the overcurrent protection trigger circuit 12, and the second end of the third resistor 124 is electrically connected to the voltage terminal VCC. The first electrode of the capacitor 125 is electrically connected to the first end of the second resistor 123, and the second electrode of the capacitor 125 is electrically connected to the second end of the second resistor 123.

[0087] By connecting the capacitor 125 in parallel at both ends of the second resistor 123, the overcurrent protection trigger circuit can be filtered to prevent noise from affecting the overcurrent protection trigger circuit, further ensuring the stability of the overcurrent protection trigger circuit, thereby ensuring the stability of the IPM module.

[0088] As a possible implementation, Fig.13 As shown, Fig.13 An IPM module output terminal provided by an embodiment of the present application is shown. Fig.13 The output end of the IPM module includes a first output end, a second output end and a third output end. The first output end, the second output end and the third output end are all electrically connected to the first end of the overcurrent protection trigger circuit 12.

[0089] As a possible implementation, Fig.14 As shown, Fig.14 The composition of the variable frequency drive circuit is shown. Fig.14 The variable frequency drive circuit 10 includes an IPM module 11, an overcurrent protection trigger circuit 12 and a motor 13. The motor 13 (commonly known as a motor) realizes the conversion or transmission of electric energy according to the law of electromagnetic induction and converts electric energy into mechanical energy. Its main function is to generate driving torque as a power source in the variable frequency drive circuit 10.

[0090] For example, Fig.15 As shown, Fig.15 The motor terminals are shown in Figure 1. Fig.15 The motor 13 includes a first terminal 131 , a second terminal 132 and a third terminal 133 .

[0091] The specific connection between the motor and the IPM module is as follows Fig.16 See Fig.16The IPM module 11 further includes a first end, a second end, and a third end. The first terminal 131 of the motor 13 is electrically connected to the first end of the IPM module 11, the second terminal 132 of the motor 13 is electrically connected to the second end of the IPM module 11, and the third terminal 133 of the motor 13 is electrically connected to the third end of the IPM module 11.

[0092] As a possible implementation manner, the IPM module triggering the overcurrent protection includes: the IPM module shutting down.

[0093] In the several embodiments provided in the present application, it should be understood that the disclosed circuits can be implemented in other ways. For example, the circuit component embodiments described above are only schematic, for example, the division of the variable frequency drive circuit is only a logical function division, and there may be other division methods in actual implementation, for example, multiple circuits or components can be combined or integrated into another circuit.

[0094] The units described as separate components, such as the motors mentioned in the embodiments, may or may not be physically separated, and the components shown as units may be one physical unit or multiple physical units, that is, they may be located in one place or distributed in multiple different places. Some or all of the classified units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0095] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed by the present invention 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 conditioner, characterized in that: include: A compressor, comprising: A variable frequency drive circuit, the variable frequency drive circuit comprising: An IPM module, the IPM module comprising an output terminal and an overcurrent protection terminal; An overcurrent protection trigger circuit, the overcurrent protection trigger circuit comprising a first end and a second end; the first end is electrically connected to the output end of the IPM module, and the second end is electrically connected to the overcurrent protection end of the IPM module; The IPM module is configured to trigger overcurrent protection when the voltage at the overcurrent protection terminal is greater than or equal to a reference voltage; The overcurrent protection trigger circuit comprises: A sampling resistor connected to the output end of the IPM module, the output end of the IPM module outputs a first current, and the first current flows through the sampling resistor; a first resistor; A second resistor; The third resistor; The first resistor, the second resistor and the third resistor are configured such that, by adjusting the resistance of the first resistor, the resistance of the second resistor and the resistance of the third resistor, when the value of the first current is greater than a preset overcurrent value, the voltage of the overcurrent protection terminal is greater than or equal to a reference voltage.

2. The air conditioner according to claim 1, characterized in that: The first end of the sampling resistor is electrically connected to the first end of the overcurrent protection trigger circuit, and the second end of the sampling resistor is electrically connected to the ground end; The first end of the first resistor is electrically connected to the first end of the overcurrent protection trigger circuit, the second end of the first resistor is electrically connected to the first end of the second resistor, the second end of the second resistor is electrically connected to the ground end, and the first end of the second resistor is also electrically connected to the second end of the overcurrent protection trigger circuit; The first end of the third resistor is electrically connected to the second end of the overcurrent protection trigger circuit, and the second end of the third resistor is electrically connected to the voltage end.

3. The air conditioner according to claim 2, characterized in that: When the value of the first current is greater than a preset overcurrent value and the voltage of the overcurrent protection terminal is greater than or equal to a reference voltage, the resistance values ​​of the first resistor, the second resistor and the third resistor satisfy: Wherein IS is the preset overcurrent value, A is the reference voltage, B is the voltage of the voltage terminal, R2 is the resistance value of the first resistor, R1 is the resistance value of the second resistor, R3 is the resistance value of the third resistor, and RS is the resistance value of the sampling resistor.

4. The air conditioner according to claim 2, characterized in that: The overcurrent protection trigger circuit also includes a capacitor; The first electrode of the capacitor is electrically connected to the first end of the second resistor, and the second electrode of the capacitor is electrically connected to the second end of the second resistor.

5. The air conditioner according to any one of claims 2 to 4, characterized in that: The voltage of the voltage terminal includes 5V.

6. The air conditioner according to any one of claims 1 to 4, characterized in that: The resistance value of the sampling resistor is smaller than the resistance value of the first resistor, the resistance value of the sampling resistor is smaller than the resistance value of the second resistor, and the resistance value of the sampling resistor is smaller than the resistance value of the third resistor.

7. The air conditioner according to any one of claims 1 to 4, characterized in that: The output end of the IPM includes a first output end, a second output end and a third output end; The first output end, the second output end and the third output end are all electrically connected to the first end of the overcurrent protection trigger circuit.

8. The air conditioner according to any one of claims 1 to 4, characterized in that: The IPM module triggering overcurrent protection includes: the IPM module shutting down.

9. The air conditioner according to any one of claims 1 to 4, characterized in that: The first resistor, the second resistor and the third resistor are adjustable resistors, and the sampling resistor is a fixed resistor.

10. The air conditioner according to any one of claims 1 to 4, characterized in that: The variable frequency drive circuit also includes: A motor, comprising a first terminal, a second terminal and a third terminal; The IPM module further includes a first end, a second end and a third end. The first terminal of the motor is electrically connected to the first end of the IPM module, the second terminal of the motor is electrically connected to the second end of the IPM module, and the third terminal of the motor is electrically connected to the third end of the IPM module.

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