Air conditioner outdoor unit

Abstract

According to the power supply scheme, a single power supply winding is adopted for supplying power, and the power supply winding converts voltage for supplying power to a first inverter driving module of a first fan and voltage for supplying power to a second inverter driving module of a second fan through a first voltage conversion circuit. The first voltage conversion circuit provides voltage input for the second voltage conversion circuit, and the second voltage conversion circuit converts voltage for supplying power to the first control module of the first fan and voltage for supplying power to the second control module of the second fan. Through the power supply mode, one winding of the transformer can be adopted to supply power to the control modules and the inversion driving modules of the two fans, two secondary side windings are not needed, two sets of transformers are not needed either, transformer winding resources are saved, and layout and wiring design of other PCB circuits is facilitated.

Description

Technical Field

[0001] The present application relates to the technical field of air conditioner control, and in particular to an air conditioner outdoor unit. Background Art

[0002] At present, some outdoor units use two fans distributed up and down to assist the outdoor unit's heat exchanger for heat exchange, which requires the corresponding control board to have two working circuits, which respectively power the circuits of the control chips of the two fans and the circuits of the inverter drive chip.

[0003] There are two commonly used power supply schemes for the working circuit of the fan. One is that the transformer includes two secondary side windings, each secondary side winding corresponds to a working circuit, so that the working circuits of the two fans can be completely isolated, but the disadvantage is that an independent winding needs to be added to the switching power supply, which increases the cost; the other is dual power supply, one switching power supply is specifically used to power the circuit of the control chip, and the other switching power supply is specifically used to power the circuit of the inverter drive chip, but the disadvantage is that it increases the area of ​​the main control board, increases the cost of electronic control, and reduces production efficiency. Summary of the invention

[0004] The embodiment of the present application provides an air-conditioning outdoor unit, which can save transformer winding resources and is beneficial to the layout and wiring design of other circuits on the PCB.

[0005] In a first aspect, an embodiment of the present application provides an air conditioner outdoor unit, the air conditioner outdoor unit comprising a power supply circuit, a first fan and a second fan, the power supply circuit comprising:

[0006] a first voltage conversion circuit, wherein a voltage input end of the first voltage conversion circuit is connected to a power supply output end of the power supply winding, and a voltage output end of the first voltage conversion circuit is used to supply power to a first inverter drive module corresponding to the first fan and a second inverter drive module corresponding to the second fan;

[0007] A second voltage conversion circuit, wherein a voltage input end of the second voltage conversion circuit is connected to a voltage output end of the first voltage conversion circuit, and a voltage output end of the second voltage conversion circuit is used to supply power to a first control module corresponding to the first fan and a second control module corresponding to the second fan.

[0008] In some embodiments, the second voltage conversion circuit includes a first voltage conversion module and a second voltage conversion module, the voltage input end of the first voltage conversion module and the voltage input end of the second voltage conversion module are both connected to the voltage output end of the first voltage conversion circuit, the voltage output end of the first voltage conversion module is used to supply power to the first control module, and the voltage output end of the second voltage conversion module is used to supply power to the second control module.

[0009] In some embodiments, the outdoor unit also includes a first sampling circuit, the first inverter drive module includes a first NU pin, a first NV pin and a first NW pin, and the first NU pin, the first NV pin and the first NW pin are all connected to the first control module through the first sampling circuit.

[0010] In some embodiments, the first sampling circuit includes a first sampling resistor and a first operational amplifier circuit, the first NU pin, the first NV pin and the first NW pin are all grounded through the first sampling resistor, the connection point between the first NU pin and the first sampling resistor is connected to the inverting input terminal of the first operational amplifier circuit, and the non-inverting input terminal of the first operational amplifier circuit is connected to a first reference voltage source.

[0011] In some embodiments, the first reference voltage source is connected to a voltage output terminal of the second voltage conversion circuit to output a first reference voltage.

[0012] In some embodiments, the outdoor unit also includes a second sampling circuit, the second inverter drive module includes a second NU pin, a second NV pin and a second NW pin, and the second NU pin, the second NV pin and the second NW pin are all connected to the second control module through the second sampling circuit.

[0013] In some embodiments, the second sampling circuit includes a second sampling resistor and a second operational amplifier circuit, the second NU pin, the second NV pin and the second NW pin are all grounded through the second sampling resistor, the connection point between the second NU pin and the second sampling resistor is connected to the non-inverting input terminal of the second operational amplifier circuit, and the inverting input terminal of the second operational amplifier circuit is connected to a second reference voltage source.

[0014] In some embodiments, the second reference voltage source is connected to a voltage output terminal of the second voltage conversion circuit to output a second reference voltage.

[0015] In some embodiments, the first fan is disposed above the second fan.

[0016] In some embodiments, the negative pole of the power supply winding, the ground terminal of the first fan and the ground terminal of the second fan are all connected to one end of an electrolytic capacitor through a common ground.

[0017] The air-conditioning outdoor unit of the embodiment of the present application has at least the following beneficial effects: for the outdoor unit having a first fan and a second fan, the embodiment of the present application adopts a single power supply winding for power supply in the power supply scheme, and the power supply winding converts a voltage for supplying power to a first inverter drive module of the first fan and a voltage for supplying power to a second inverter drive module of the second fan through a first voltage conversion circuit. The first voltage conversion circuit provides a voltage input for the second voltage conversion circuit, and the second voltage conversion circuit converts a voltage for supplying power to a first control module of the first fan and a voltage for supplying power to a second control module of the second fan. Therefore, it can be seen that through the above-mentioned power supply method, one winding of the transformer can be used to power the control modules and inverter drive modules of the two fans. There is no need to use two secondary side windings or two sets of transformers, which saves transformer winding resources and is beneficial to the layout and wiring design of other circuits on the PCB.

[0018] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained through the structures particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of module connection of a power supply circuit in an air conditioner outdoor unit provided by an embodiment of the present application;

[0020] Figure 2 This is a schematic diagram of the connection between a fan motor, an inverter drive module and a control module provided by an embodiment of the present application;

[0021] Figure 3 It is a circuit connection diagram of a fan grounding method provided by an embodiment of the present application. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. In addition, the characteristics, operations or features described in the specification can be combined in any appropriate manner to form various implementation methods. At the same time, the steps or actions in the method description can also be replaced or adjusted in order in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the accompanying drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a necessary sequence, unless otherwise specified that a certain sequence must be followed.

[0023] In the description of this application, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0024] The serial numbers of the components in this document, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings).

[0025] In household high-power air-conditioning products or light commercial air-conditioning products, the capacity of the outdoor unit is relatively large, and generally a design with two upper and lower fans (dual fans) can be adopted. Accordingly, the motor control circuit and control logic of the dual fans need to be designed accordingly.

[0026] Generally speaking, a fan includes a motor for driving the fan blades and an inverter drive chip for driving the motor, and the control of the inverter drive chip is realized by outputting a PWM signal from a control chip such as an MCU. Therefore, the power supply to the fan is divided into power supply to the inverter drive chip and power supply to the control chip. The working voltages of the two are different and voltage conversion is required. There are two power supply schemes for dual fan products commonly used in related technologies. One scheme is to use a transformer to set two windings on the secondary side. The two windings respectively power the control chip and the inverter drive chip of the two fans, so that the power supply of the two parts of the circuit of the two fans is completely isolated. However, the disadvantage is that an independent winding needs to be added to the switching power supply, which increases the cost. Another scheme is to use two transformers, each with a winding on the secondary side. The two independent windings respectively power the control chip and the inverter drive chip of the two fans, so that the power supply of the two parts of the circuit of the two fans is completely isolated. However, the disadvantage is that the main control board area is increased, the electric control cost is increased, and the production efficiency is reduced.

[0027] Based on this, an embodiment of the present application provides an air-conditioning outdoor unit, which adopts a single power supply winding for power supply in the power supply scheme. The power supply winding converts the voltage for powering the first inverter drive module of the first fan and the voltage for powering the second inverter drive module of the second fan through the first voltage conversion circuit. The first voltage conversion circuit provides voltage input for the second voltage conversion circuit, and the second voltage conversion circuit converts the voltage for powering the first control module of the first fan and the voltage for powering the second control module of the second fan. Therefore, it can be seen that through the above-mentioned power supply method, one winding of the transformer can be used to power the control modules and inverter drive modules of the two fans. There is no need to use two secondary side windings or two sets of transformers, which saves transformer winding resources and is beneficial to the layout and wiring design of other circuits of the PCB.

[0028] The air conditioner outdoor unit is described below with reference to the accompanying drawings.

[0029] Reference Figure 1 and 2 As shown, Figure 1 An air conditioner outdoor unit is provided in an embodiment of the present application. Figure 2 It is a circuit diagram of a fan motor connected to an inverter drive module and a control module; the air conditioner outdoor unit includes a power supply circuit, a first fan and a second fan, and the power supply circuit includes:

[0030] A first voltage conversion circuit, wherein a voltage input end of the first voltage conversion circuit is connected to a power supply output end of the power supply winding, and a voltage output end of the first voltage conversion circuit is used to supply power to a first inverter drive module corresponding to the first fan and a second inverter drive module corresponding to the second fan;

[0031] A second voltage conversion circuit, wherein a voltage input end of the second voltage conversion circuit is connected to a voltage output end of the first voltage conversion circuit, and the voltage output end of the second voltage conversion circuit is used to supply power to a first control module corresponding to the first fan and a second control module corresponding to the second fan.

[0032] The outdoor unit of the embodiment of the present application adopts dual-fan control, that is, it includes a first fan and a second fan, so there are two motors that need to be controlled. The positional relationship between the first fan and the second fan is not limited. For example, the first fan and the second fan can be arranged up and down, or left and right. The switching power supply of the outdoor unit converts the AC input on the primary side into a DC output on the secondary side through a transformer. The embodiment of the present application sets a single secondary side winding to power the inverter drive module and the control module of the two fans. The inverter drive module includes an inverter drive chip (such as an IPM (Intelligent Power Module) chip), and the control module includes a control chip (such as a controller such as an MCU). The operating voltages of the inverter drive chip and the control chip are different. Therefore, the DC voltage output through the secondary side winding needs to be further converted into two different voltages to power the inverter drive chip and the control chip. In order to avoid using two secondary side windings or two transformers, the embodiment of the present application sets a first voltage conversion circuit and a second voltage conversion circuit, the first voltage conversion circuit is connected to the secondary side winding to convert the voltage required by the inverter drive chip, and the second voltage conversion circuit is connected to the output of the first voltage conversion circuit to convert the voltage required by the control chip according to the voltage output by the first voltage conversion circuit. Therefore, it can be known that the first voltage conversion circuit divides at least two voltage outputs, one corresponding to the inverter drive chip / inverter drive module, and the other corresponding to the input of the second voltage conversion circuit, and the second voltage conversion circuit divides at least two voltage outputs, one corresponding to the control chip / control module of the first fan, and the other corresponding to the control chip / control module of the second fan. Through the above voltage conversion method, a secondary side winding can be used to convert into two voltages to supply power to the inverter drive module and control module of the first fan and the second fan respectively, thereby saving transformer winding resources and facilitating the layout and wiring design of other circuits of the PCB.

[0033] It can be understood that the above-mentioned inverter drive module is a general term for peripheral circuits and components for inverter drive, including inverter drive chips, except that the voltage converted by the first voltage conversion circuit is mainly supplied to the inverter drive chip. At this time, the inverter drive chips corresponding to the first fan and the second fan can use chips of the same model or chips with the same working voltage, so that the voltage converted by the first voltage conversion circuit can satisfy the two inverter drive chips at the same time. The above-mentioned control module is a general term for peripheral circuits and components related to control, including control chips, except that the voltage converted by the second voltage conversion circuit is mainly supplied to the control chip. At this time, the control chips corresponding to the first fan and the second fan can use chips of the same model or chips with the same working voltage, so that the voltage converted by the second voltage conversion circuit can satisfy the two control chips at the same time. Of course, two conversion modules can be set in the second voltage conversion circuit to output two voltages to two control chips. At this time, the same or different types of control chips can be selected according to the output voltages of the two conversion modules.

[0034] In addition, the operating voltage of the inverter drive chip is generally higher than the operating voltage of the control chip. Therefore, the voltage converted by the first voltage conversion circuit is higher than the voltage converted by the second voltage conversion circuit. Therefore, the first voltage conversion circuit and the second conversion circuit are both step-down circuits. The selection of corresponding step-down chips or devices can easily realize step-down conversion.

[0035] In some embodiments, the second voltage conversion circuit includes a first voltage conversion module and a second voltage conversion module, the voltage input end of the first voltage conversion module and the voltage input end of the second voltage conversion module are both connected to the voltage output end of the first voltage conversion circuit, the voltage output end of the first voltage conversion module is used to supply power to the first control module, and the voltage output end of the second voltage conversion module is used to supply power to the second control module.

[0036] In this embodiment, two voltage conversion modules are set in the second voltage conversion circuit to output voltage to the control module respectively, that is, the voltage input end of the first voltage conversion module and the second voltage conversion module are connected to the voltage output end of the first voltage conversion circuit, and the voltage converted by the first voltage conversion circuit is further converted. For example, a voltage conversion chip is used in the first voltage conversion circuit to convert a 15V voltage, which is supplied to the first inverter drive module and the second inverter drive module, and another voltage conversion chip is used in the second voltage conversion circuit to convert a 5V voltage, which is supplied to the first control module and the second control module. It can be understood that the first voltage conversion module and the second voltage conversion module can be different, and can also be designed to output different voltages for different control modules.

[0037] Reference Figure 3As shown, in some embodiments, the negative pole of the power supply winding, the ground terminal of the first fan and the ground terminal of the second fan are all connected to one end of an electrolytic capacitor through a common ground. Figure 3 The ground terminal of the upper fan (in Figure 1 GND1 in the figure) and the second fan (in Figure 3 The ground terminal of the fan (in Figure 1 In addition, one end of an electrolytic capacitor is connected to a common ground, and the common ground is also connected to the power supply end of the first fan and the grounding end of the second fan, thereby realizing a common ground connection between the power supply winding, the first fan and the second fan and grounding through the electrolytic capacitor on the PCB to stabilize the current in the circuit.

[0038] In some embodiments, the outdoor unit also includes a first sampling circuit, the first inverter drive module includes a first NU pin, a first NV pin and a first NW pin, and the first NU pin, the first NV pin and the first NW pin are all connected to the first control module through the first sampling circuit.

[0039] Taking the first inverter drive module as an IPM chip as an example, the IPM chip has 6 built-in power tubes to form three bridge arms, providing 6 PMW drive pins, and 6 PWM drive pins connected to the corresponding 6 PWM signal output pins of the control chip / control module. Based on the three bridge arms, the three-phase positive terminal pin and the three-phase negative terminal pin are led out. The three-phase positive terminal pin is U, V, and W and is connected to the three-phase input of the motor of the first fan. The three-phase negative terminal pin is NU, NV, and NW and is grounded. In the embodiment of the present application, the first sampling circuit is connected at the three pins NU, NV, and NW, and the ground current of the three phases U, V, and W is collected by the first sampling circuit to determine the current working state of the first fan.

[0040] In some embodiments, the first sampling circuit includes a first sampling resistor RS1 and a first operational amplifier circuit, the first NU pin, the first NV pin and the first NW pin are all grounded through the first sampling resistor RS1, the connection point between the first NU pin and the first sampling resistor RS1 is connected to the inverting input terminal of the first operational amplifier circuit, and the non-inverting input terminal of the first operational amplifier circuit is connected to the first reference voltage source.

[0041] The first sampling resistor RS1 is connected in series between the three-phase pins NU, NV, and NW and the ground terminal, and is a single resistor sampling. The connection point between the first sampling resistor RS1 and the three-phase pins NU, NV, and NW is connected to the inverting input terminal of the first operational amplifier circuit through a resistor R1, and the connection point between the first sampling resistor RS1 and the ground terminal is connected to the non-inverting input terminal of the first operational amplifier circuit through a resistor R2, and the first reference voltage source is also connected to the non-inverting input terminal of the first operational amplifier circuit. Therefore, the input signal of the first operational amplifier circuit is the voltage difference across the first sampling resistor RS1. The signal is routed differentially to eliminate the common-mode noise of the sampling signal to the ground, so that the sampling signal avoids common-mode interference and improves sampling accuracy and stability.

[0042] The first reference voltage source is connected to the voltage output terminal of the second voltage conversion circuit to output the first reference voltage. Figure 2 As shown, the voltage output end of the second voltage conversion circuit is connected to the non-inverting input end of the first operational amplifier circuit through a resistor R6, and the non-inverting input end of the first operational amplifier circuit is also grounded through a resistor R5. The reference voltage of the non-inverting input end of the first operational amplifier circuit is limited by the voltage divider of the resistor R6.

[0043] In some embodiments, the outdoor unit also includes a second sampling circuit, the second inverter drive module includes a second NU pin, a second NV pin and a second NW pin, and the second NU pin, the second NV pin and the second NW pin are all connected to the second control module through the second sampling circuit.

[0044] Taking the second inverter drive module as an IPM chip as an example, the IPM chip has 6 built-in power tubes to form three bridge arms, providing 6 PMW drive pins, and 6 PWM drive pins connected to the corresponding 6 PWM signal output pins of the control chip / control module. Based on the three bridge arms, the three-phase positive terminal pin and the three-phase negative terminal pin are led out. The three-phase positive terminal pin is U, V, and W and is connected to the three-phase input of the motor of the second fan. The three-phase negative terminal pin is NU, NV, and NW and is grounded. In the embodiment of the present application, the second sampling circuit is connected at the three pins NU, NV, and NW, and the ground current of the three phases U, V, and W is collected by the second sampling circuit to determine the current working state of the second fan.

[0045] In some embodiments, the second sampling circuit includes a second sampling resistor RS2 and a second operational amplifier circuit, the second NU pin, the second NV pin and the second NW pin are all grounded through the second sampling resistor RS2, the connection point between the second NU pin and the second sampling resistor RS2 is connected to the non-inverting input terminal of the second operational amplifier circuit, and the inverting input terminal of the second operational amplifier circuit is connected to the second reference voltage source.

[0046] The second sampling resistor RS2 is connected in series between the three-phase pins NU, NV, and NW and the ground terminal, and is a single resistor sampling. The connection point between the second sampling resistor RS2 and the three-phase pins NU, NV, and NW is connected to the inverting input terminal of the first operational amplifier circuit through a resistor R8, and the connection point between the second sampling resistor RS2 and the ground terminal is connected to the non-inverting input terminal of the second operational amplifier circuit through a resistor R9, and the second reference voltage source is also connected to the non-inverting input terminal of the second operational amplifier circuit. Therefore, the input signal of the second operational amplifier circuit is the voltage difference across the second sampling resistor RS2. The signal is routed differentially to eliminate the common-mode noise of the sampling signal to the ground, so that the sampling signal avoids common-mode interference and improves sampling accuracy and stability.

[0047] The second reference voltage source is connected to the voltage output terminal of the second voltage conversion circuit to output the second reference voltage. Figure 2 As shown, the voltage output terminal of the second voltage conversion circuit is connected to the non-inverting input terminal of the second operational amplifier circuit through a resistor R13, and the non-inverting input terminal of the second operational amplifier circuit is also grounded through a resistor R12. The reference voltage of the non-inverting input terminal of the second operational amplifier circuit is limited by the voltage divider of the resistor R13.

[0048] For an outdoor unit having a first fan and a second fan, the embodiment of the present application adopts a single power supply winding for power supply in the power supply scheme. The power supply winding converts a voltage for supplying power to a first inverter drive module of the first fan and a voltage for supplying power to a second inverter drive module of the second fan through a first voltage conversion circuit. The first voltage conversion circuit provides a voltage input for the second voltage conversion circuit. The second voltage conversion circuit converts a voltage for supplying power to a first control module of the first fan and a voltage for supplying power to a second control module of the second fan. Therefore, it can be seen that through the above-mentioned power supply method, one winding of the transformer can be used to power the control modules and inverter drive modules of the two fans. There is no need to use two secondary side windings or two sets of transformers, which saves transformer winding resources and is beneficial to the layout and wiring design of other circuits on the PCB.

[0049] For the air conditioner outdoor unit of the above embodiment, at least one of the first fan and the second fan can be started through the above power supply circuit when receiving the start command; if the first fan and the second fan are started at the same time, the first control module adjusts the first inverter drive module to output the first carrier frequency, and the second control module adjusts the second inverter drive module to output the second carrier frequency, the first fan operates based on the first carrier frequency, and the second fan operates based on the second carrier frequency. In order to avoid the problem of resonance interference caused by the consistency of the carrier frequencies of the first fan and the second fan, the first carrier frequency and the second carrier frequency are different, so as to avoid resonance interference caused by the consistency of the signals when the dual fans are started.

[0050] If the first fan is turned on alone, the first control module adjusts the first inverter drive module to output the first carrier frequency; after the first fan is turned on alone, if the second fan is turned on, the second control module adjusts the second inverter drive module to output the second carrier frequency, and makes the first carrier frequency and the second carrier frequency different, so as to avoid resonance interference caused by consistent signals of the two fans.

[0051] Similarly, if the second fan is turned on alone, the second control module adjusts the second inverter drive module to output the second carrier frequency; after the second fan is turned on alone, if the first fan is turned on again, the first control module adjusts the first inverter drive module to output the first carrier frequency, and makes the first carrier frequency and the second carrier frequency different, thereby avoiding resonance interference caused by consistent signals of the two fans.

[0052] Therefore, whether starting both fans at the same time or starting the first fan / the second fan one after the other, the carrier frequency of the first fan can be set different from the carrier frequency of the second fan, thereby avoiding resonance interference between the first fan and the second fan.

[0053] In summary, a single secondary winding is combined with a first voltage conversion circuit and a second voltage conversion circuit to provide matching voltages for the dual inverter drive module and the dual control module of the dual-fan outdoor unit, thereby avoiding the use of two secondary windings for power supply or two transformers for power supply. At the same time, sampling resistors are set corresponding to the dual fans, and the working status of the dual fans is obtained through the sampling resistors and operational amplifier circuits, which can provide more control methods for the control module.

[0054] The power supply circuit of the air conditioner outdoor unit of the present application is described in detail below through a specific example.

[0055] Outdoor structure:

[0056] ① Use a secondary winding of the transformer for power supply, refer to Figure 1 As shown;

[0057] ② Set up the first fan with vertical distribution ( Figure 2 and Figure 3 The upper fan is shown in the figure) and the second fan ( Figure 2 and Figure 3 Indicated as downwind fan);

[0058] ③Two MCU control units, in Figure 2 In the figure, they are represented as MCU1 and MCU2;

[0059] ④Two IPM modules, Figure 2 Indicated as IPM1 and IPM2;

[0060] ⑤Two op amp chip modules, Figure 2Indicated as IC1 and IC2;

[0061] ⑥The fan current is sampled using a single resistor. Figure 2 The sampling resistor of the first fan is represented by RS1, and the sampling resistor of the second fan is represented by RS2;

[0062] ⑦ The first fan and the second fan use motors with the same power, model and parameters; due to the use of dual chips, fans of different models and parameters can also be independently controlled according to needs;

[0063] Working principle of each circuit module:

[0064] ① The power supply unit outputs voltage through the switching transformer winding, and then outputs 15V and 5V power supply voltages through the first voltage regulator chip (output voltage is 15V) and the second voltage regulator chip (output voltage is 5V). 15V provides power for the IPM module, and 5V provides power for the MCU control unit and operational amplifier circuit.

[0065] ②The MCU control unit is the basic unit for generating PWM control signals. It can also collect the current signal flowing through the sampling resistor (non-inductive resistor can be selected) through the operational amplifier circuit, and output 6 PWM control signals after the control algorithm of the MCU control unit.

[0066] ③ The operational amplifier divides the voltage through R13 and R12, and combines with R10, R11, R14, and R15 to provide a reference voltage Vref for the positive input terminal of the operational amplifier. That is, when the current flowing through the fan is 0, the output voltage of the operational amplifier is Vref;

[0067] ④ The input signal of the op amp is the voltage difference across the sampling resistor. This signal is routed differentially to eliminate the common-mode noise of the sampling signal to the ground, thereby avoiding common-mode interference and improving sampling accuracy and stability.

[0068] ⑤The IPM drive module uses 6-way PWM control signals as input signals, which can be controlled by MCU instructions to set different carrier frequencies for the 6-way PWM. The PWM output acts on the 6 MOS or IGBT power tubes integrated inside the IPM module, so that the output U, V, and W three-phase windings receive sinusoidal drive currents, thereby controlling the operation of the fan. The current frequency and amplitude in the U, V, and W three-phase windings can be changed to obtain different fan speeds.

[0069] Therefore, under the premise of power supply by a single power winding, this example solves the design problem of mutual interference of fan sampling signals in the dual-fan dual-chip control system; one winding of the transformer is used to power the control chip and two modules of the two fans, saving transformer winding resources and facilitating the layout and wiring design of other PCB circuits; the fan current is sampled by a single resistor, which saves four sampling resistors compared to the three-resistance sampling method of dual fans, reduces the number of resistors, and reduces the cost of sampling resistors; the op amp circuit is added to use differential signal sampling to eliminate the common-mode noise of the sampling signal to the ground, so that the sampling signal avoids common-mode interference, and sampling is performed according to the differential signal, which greatly reduces the requirements for PCB layout and wiring, and the influence of common-mode noise is offset by the differential signal line, thereby improving sampling accuracy and stability.

[0070] It should be understood that in the present application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0071] In several embodiments provided in the present application, it should be understood that the disclosed systems, apparatuses and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely schematic, for example, the division of units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of apparatuses or units, which can be electrical, mechanical or other forms. The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the scheme of this embodiment.

[0072] It should also be understood that the various implementations provided in the embodiments of the present application can be combined arbitrarily to achieve different technical effects.

[0073] The above is a specific description of the preferred implementation of the present application, but the present application is not limited to the above-mentioned implementation mode. Technical personnel familiar with the field can also make various equivalent deformations or substitutions without violating the spirit of the present application. These equivalent deformations or substitutions are all included in the scope defined by the claims of the present application.

Claims

1. An air conditioner outdoor unit, characterized in that: The air conditioner outdoor unit comprises a power supply circuit, a first fan and a second fan, and the power supply circuit comprises: a first voltage conversion circuit, wherein a voltage input end of the first voltage conversion circuit is connected to a power supply output end of the power supply winding, and a voltage output end of the first voltage conversion circuit is used to supply power to a first inverter drive module corresponding to the first fan and a second inverter drive module corresponding to the second fan; A second voltage conversion circuit, wherein a voltage input end of the second voltage conversion circuit is connected to a voltage output end of the first voltage conversion circuit, and a voltage output end of the second voltage conversion circuit is used to supply power to a first control module corresponding to the first fan and a second control module corresponding to the second fan.

2. The air conditioner outdoor unit according to claim 1, characterized in that: The second voltage conversion circuit includes a first voltage conversion module and a second voltage conversion module, the voltage input end of the first voltage conversion module and the voltage input end of the second voltage conversion module are both connected to the voltage output end of the first voltage conversion circuit, the voltage output end of the first voltage conversion module is used to supply power to the first control module, and the voltage output end of the second voltage conversion module is used to supply power to the second control module.

3. The air conditioner outdoor unit according to claim 1, characterized in that: The outdoor unit further includes a first sampling circuit, the first inverter drive module includes a first NU pin, a first NV pin and a first NW pin, and the first NU pin, the first NV pin and the first NW pin are all connected to the first control module through the first sampling circuit.

4. The air conditioner outdoor unit according to claim 3, characterized in that: The first sampling circuit includes a first sampling resistor and a first operational amplifier circuit, the first NU pin, the first NV pin and the first NW pin are all grounded through the first sampling resistor, the connection point of the first NU pin and the first sampling resistor is connected to the inverting input terminal of the first operational amplifier circuit, and the non-inverting input terminal of the first operational amplifier circuit is connected to a first reference voltage source.

5. The air conditioner outdoor unit according to claim 4, characterized in that: The first reference voltage source is connected to the voltage output terminal of the second voltage conversion circuit to output a first reference voltage.

6. The air conditioner outdoor unit according to claim 1, characterized in that: The outdoor unit also includes a second sampling circuit, the second inverter drive module includes a second NU pin, a second NV pin and a second NW pin, and the second NU pin, the second NV pin and the second NW pin are all connected to the second control module through the second sampling circuit.

7. The air conditioner outdoor unit according to claim 6, characterized in that: The second sampling circuit includes a second sampling resistor and a second operational amplifier circuit, the second NU pin, the second NV pin and the second NW pin are all grounded through the second sampling resistor, the connection point of the second NU pin and the second sampling resistor is connected to the non-inverting input terminal of the second operational amplifier circuit, and the inverting input terminal of the second operational amplifier circuit is connected to a second reference voltage source.

8. The air conditioner outdoor unit according to claim 7, characterized in that: The second reference voltage source is connected to the voltage output terminal of the second voltage conversion circuit to output a second reference voltage.

9. The air conditioner outdoor unit according to claim 1, characterized in that: The first fan is arranged above the second fan.

10. The air conditioner outdoor unit according to claim 1, characterized in that: The negative electrode of the power supply winding, the ground terminal of the first fan and the ground terminal of the second fan are all connected to one end of an electrolytic capacitor through a common ground.

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