Air conditioner and control method of PFC (Power Factor Correction) circuit for air conditioner

Abstract

The invention provides an air conditioner and a control method of a PFC (Power Factor Correction) circuit for the air conditioner. The air conditioner comprises a plurality of PFC channels which are arranged in parallel; the controller is configured to obtain the initial current distribution coefficients of the plurality of PFC channels and the actual temperature value of the IGBT switch tube; adjusting the initial current distribution coefficient according to the actual temperature value to obtain a target current distribution coefficient; the actual temperature value is adjusted according to the target current distribution coefficient until the actual temperature values of the multiple IGBT switch tubes are consistent, temperature balance control over the IGBT switch tubes of the multiple PFC channels is achieved, the phenomenon that the PFC circuit is damaged due to the fact that the temperature of one IGBT switch tube of the multiple PFC channels is too high is avoided, and therefore the stability and reliability of operation of the PFC circuit are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and in particular to an air conditioner and a control method of a PFC circuit used therefor. Background Art

[0002] An interleaved PFC (Power Factor Correction) circuit is a circuit that sets multiple PFC channels in parallel and is applicable to two or more PFC channels.

[0003] In the related art, after the PFC circuit is started, the current values ​​of multiple PFC channels are usually controlled to maintain a balance, that is, current equalization control. However, in actual applications, due to certain deviations in the heat dissipation conditions, device parameters and circuit parameters of each IGBT switch tube, maintaining the current balance of each PFC channel cannot guarantee that the actual temperature value of each IGBT switch tube is consistent. It is easy for one of the IGBT switch tubes in multiple PFC channels to have an excessively high temperature, causing damage to the PFC circuit, and the stability and safety of the PFC circuit operation are low. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0005] To this end, an object of the present invention is to provide an air conditioner, which realizes temperature balance control of IGBT switch tubes of multiple PFC channels to avoid damage to the PFC circuit due to excessive temperature of one of the IGBT switch tubes of the multiple PFC channels, thereby improving the stability and reliability of the operation of the PFC circuit.

[0006] Therefore, a second object of the present invention is to provide a control method for a PFC circuit.

[0007] In order to achieve the above-mentioned purpose, an embodiment of the first aspect of the present invention provides an air conditioner, which is used for a PFC circuit, and the air conditioner includes: a plurality of PFC channels arranged in parallel, which are used to correct the input current waveform of the air conditioner; an IGBT switch tube, which is arranged in each of the PFC channels, and is used to turn on or off the PFC channel; a temperature monitoring module, which is used to monitor the actual temperature value of each of the IGBT switch tubes; a controller, which is configured to: after the PFC circuit is started, control the plurality of PFC channels to operate with the same current; when the plurality of PFC channels operate with the same current, obtain the actual temperature values ​​of the IGBT switch tubes in the plurality of PFC channels; determine the target current distribution coefficients of the plurality of PFC channels according to the actual temperature values; and adjust the current value of the PFC channel according to the target current distribution coefficient until the actual temperature values ​​of the plurality of IGBT switch tubes are consistent.

[0008] According to the air conditioner of the embodiment of the present invention, by monitoring the actual temperature value of the IGBT switch tube, the target current distribution coefficient of each PFC channel corresponding thereto is determined, and the current value of the corresponding PFC channel is reasonably distributed according to the target current distribution coefficient, so that the temperature value of the IGBT switch tube is adjusted according to the distributed current value, so that the actual temperature value of the IGBT switch tube tends to be consistent. Therefore, by determining the target current distribution coefficient corresponding to the actual temperature value, the current value of the PFC channel is adjusted, and the temperature balance control of the IGBT switch tubes of multiple PFC channels is achieved, so that the damage of the PFC circuit caused by the excessive temperature of one of the IGBT switch tubes of the multiple PFC channels is avoided, thereby improving the stability and reliability of the operation of the PFC circuit.

[0009] In some embodiments, when adjusting the current value of the PFC channel according to the target current distribution coefficient, the controller is configured to: obtain a target total current value of the PFC circuit; calculate the product of the target total current value and the target current distribution coefficient of the PFC channel to obtain the target current value of the corresponding PFC channel; and adjust the current value of the PFC channel to the corresponding target current value.

[0010] In some embodiments, when the target current distribution coefficient is determined according to the actual temperature value, the target current distribution coefficient is obtained by the following formula: Rn=(1 / Tn) / (1 / T1+1 / T2+1 / T3+…+1 / TN); wherein N is the number of the PFC channels, N is an integer greater than 1, n is the current PFC channel, Rn is the target current distribution coefficient of PFC channel n, Tn is the actual temperature value of the IGBT switch tube of PFC channel n, n is a positive integer and n is less than or equal to N, and R1+R2+R3+…Rn=1.

[0011] In some embodiments, before adjusting the current value of the PFC channel according to the target current distribution coefficient, the controller is further configured to: determine whether the PFC circuit runs to a stable state; if the PFC circuit runs to a stable state, perform an action of adjusting the current value of the PFC channel according to the actual temperature value of the IGBT switch tube; if the PFC circuit does not run to a stable state, temporarily do not perform the action of adjusting the current value of the PFC channel according to the actual temperature value of the IGBT switch tube, until the PFC circuit runs to a stable state, and then perform the action of adjusting the current value of the PFC channel according to the actual temperature value of the IGBT switch tube.

[0012] In some embodiments, when it is determined that the actual temperature value of the IGBT switch tube is continuously and stably within a set temperature range within a set time period, it is determined that the PFC circuit has run to a stable state.

[0013] In some embodiments, when controlling the plurality of PFC channels to operate at the same current, the controller is configured to: divide the target total current value of the PFC circuit equally according to the number of the PFC channels to obtain an equalized current; and control each of the PFC channels to operate at the equalized current.

[0014] In some embodiments, when the target current distribution coefficients of the plurality of PFC channels are determined according to the actual temperature value, if the actual temperature value of the IGBT switch tube is larger, the corresponding target current distribution coefficient is smaller.

[0015] In some embodiments, when the target current distribution coefficients of the plurality of PFC channels are determined according to the actual temperature value, if the actual temperature value of the IGBT switch tube is smaller, the corresponding target current distribution coefficient is larger.

[0016] In some embodiments, when adjusting the current value of the PFC channel to the corresponding target current value, the controller is further configured to: determine PWM modulation pulses corresponding to the target current values ​​of multiple PFC channels; and control the on or off duration of the IGBT switch tube according to the PWM modulation pulse to adjust the current value of the PFC channel.

[0017] In order to achieve the above-mentioned object, an embodiment of a second aspect of the present invention provides a control method of a PFC circuit, which is used for an air conditioner, and the method comprises: after the PFC circuit is started, controlling multiple PFC channels to operate with the same current; when the multiple PFC channels operate with the same current, obtaining initial current distribution coefficients of the multiple PFC channels and actual temperature values ​​of the IGBT switch tubes; adjusting the initial current distribution coefficient according to the actual temperature value to obtain a target current distribution coefficient; and adjusting the current value of the PFC channel according to the target current distribution coefficient until the actual temperature values ​​of the multiple IGBT switch tubes are consistent.

[0018] According to the control method of the PFC circuit of the embodiment of the present invention, by monitoring the actual temperature value of the IGBT switch tube, the target current distribution coefficient of each PFC channel corresponding thereto is determined, and the current value of the corresponding PFC channel is reasonably distributed according to the target current distribution coefficient, so that the temperature value of the IGBT switch tube is adjusted according to the distributed current value, so that the actual temperature value of the IGBT switch tube tends to be consistent. Therefore, by determining the target current distribution coefficient corresponding to the actual temperature value, the current value of the PFC channel is adjusted, and the temperature balance control of the IGBT switch tubes of multiple PFC channels is realized, so that the damage of the PFC circuit caused by the excessive temperature of one of the IGBT switch tubes of the multiple PFC channels is avoided, thereby improving the stability and reliability of the operation of the PFC circuit.

[0019] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0021] Figure 1 is a structural schematic diagram of an air conditioner according to an embodiment of the present invention;

[0022] Figure 2 is a hardware configuration block diagram of a controller according to an embodiment of the present invention;

[0023] Figure 3 is a structural block diagram of an air conditioner according to an embodiment of the present invention;

[0024] Figure 4 is a schematic diagram of a control method for a PFC circuit of an air conditioner according to an embodiment of the present invention;

[0025] Figure 5 is a circuit diagram of an air conditioner according to an embodiment of the present invention;

[0026] Figure 6 is a flow chart of a control method of a PFC circuit of an air conditioner according to an embodiment of the present invention;

[0027] Figure 7 is a flow chart of a control method of a PFC circuit according to an embodiment of the present invention.

[0028] Description of the drawings: air conditioner 100;

[0029] Indoor unit 11; air outlet 12; return air outlet 13; outdoor unit 14;

[0030] Wind deflector 2; control device 200;

[0031] Controller 71;

[0032] Bus 81; Memory 82; Processor 83; Communication interface 84;

[0033] PFC channel 101; IGBT switch tube 102; temperature monitoring module 103. DETAILED DESCRIPTION

[0034] The present invention is described in detail below by way of exemplary embodiments. However, it should be understood that elements, structures, and features in one embodiment may also be beneficially combined in other embodiments without further description.

[0035] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0036] 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.

[0037] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] The present application embodiment provides an air conditioner 100, referring to Figure 1 The air conditioner 100 includes a refrigeration system for exchanging heat with indoor air to meet cooling or heating needs.

[0039] The refrigeration system includes a compressor, a condenser, an expansion valve, and an evaporator, and the air conditioner 100 in this application performs a refrigeration cycle of the air conditioner 100 by using the compressor, the condenser, the expansion valve, and the evaporator. The refrigeration cycle includes a series of processes involving compression, condensation, expansion, and evaporation, and supplies refrigerant to the conditioned and heat-exchanged air.

[0040] The compressor compresses the refrigerant gas in a high temperature and high pressure state and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser. The condenser condenses the compressed refrigerant into a liquid phase, and the heat is released to the surrounding environment through the condensation process.

[0041] The expansion valve expands the high-temperature and high-pressure liquid refrigerant condensed in the condenser into a low-pressure liquid refrigerant. The evaporator evaporates the refrigerant expanded in the expansion valve and returns the low-temperature and low-pressure refrigerant gas to the compressor.

[0042] The evaporator can achieve a refrigeration effect by using the latent heat of evaporation of the refrigerant to perform heat exchange with the material to be cooled. In the whole cycle, the air conditioner 100 can adjust the temperature of the indoor space.

[0043] The outdoor unit of the air conditioner 100 refers to a portion of a refrigeration cycle including a compressor and an outdoor heat exchanger, the indoor unit of the air conditioner 100 includes an indoor heat exchanger, and an expansion valve may be provided in the indoor unit or the outdoor unit.

[0044] The indoor heat exchanger and the outdoor heat exchanger function as a condenser or an evaporator. When the indoor heat exchanger functions as a condenser, the air conditioner 100 functions as a heater in a heating mode, and when the indoor heat exchanger functions as an evaporator, the air conditioner 100 functions as a cooler in a cooling mode.

[0045] The air conditioner 100 in the present application includes an indoor unit 11 and an outdoor unit 14, and the indoor unit 11 and the outdoor unit 14 can be configured as an integrated unit or a split unit. The indoor unit 11 can be configured as a wall-mounted unit, a ceiling unit, a duct unit, etc., and the indoor unit 11 is installed at the top or top of the indoor room.

[0046] Reference Figure 1 Taking an indoor wall mounted unit as an example, the indoor wall mounted unit is usually installed at a location such as an indoor wall. For another example, an indoor cabinet unit (not shown in the figure) is also a form of the indoor unit 11 .

[0047] Taking a split unit as an example, the air conditioner 100 includes an indoor unit 11 and an outdoor unit 14, wherein the outdoor unit 14 is usually arranged outdoors for heat exchange in the indoor environment.

[0048] In addition, as shown in the figure, the air conditioner 100 is provided with a controller 71 to control the operation of various components in the air conditioner 100, so that the various components of the air conditioner 100 operate to realize various predetermined functions of the air conditioner 100. Among them, the air conditioner 100 is also provided with a control device 200. Exemplarily, the control device 200 is specifically configured as a remote controller, which has the function of communicating with the controller 71 using infrared or other communication methods, for example. The remote controller is used for the user to perform various controls on the air conditioner 100 and realize the interaction between the user and the air conditioner 100.

[0049] The indoor unit 11 of the air conditioner 100 in the embodiment of the present application is arranged at the top or upper part of the room. Generally speaking, the installation height of the indoor unit 11 is higher than the user activity area. The indoor unit 11 includes a return air port 13 and an air outlet 12 connected to the room. The indoor air enters the indoor unit 11 through the return air port 13 and flows back into the room through the air outlet 12.

[0050] The refrigerant circulation loop in the present application circulates the refrigerant in a loop composed of a compressor, a condenser, an expansion valve, and an evaporator, wherein one of the condenser and the evaporator is an outdoor heat exchanger and the other is an indoor heat exchanger. The indoor heat exchanger is used to exchange heat with the air in the indoor unit 11, and the outdoor unit 14 heat exchanger is used to exchange heat with the air in the outdoor unit 14, thereby realizing the cooling or heating requirements of the air conditioner 100.

[0051] The indoor unit 11 also includes an indoor fan, which is arranged in the indoor heat exchanger near the return air port 13 or the air outlet 12 to deliver the heat-exchanged air to the room. The indoor fan includes multiple gears to change the air outlet speed of the air outlet 12.

[0052] An air guide plate 2 is provided at the position of the air outlet 12. The air guide plate 2 adjusts the outflow direction of the air flowing through the air outlet 12 by changing the relative rotation angle between the air guide plate 2 and the air outlet 12, thereby affecting the indoor air temperature stratification.

[0053] In the embodiment shown in the present application, the air conditioner 100 further includes a controller 71, which refers to a device that can generate an operation control signal according to the instruction operation code and the timing signal to instruct the air conditioner 100 to execute the control instruction. For example, in response to a power-on or power-off instruction received from a user, the controller 71 can execute an operation related to the object selected by the power-on or power-off instruction.

[0054] The present application embodiment also provides a hardware structure diagram of a controller 71, such as Figure 2 As shown, the controller 71 includes a processor 83, and optionally, further includes a memory 82 and a communication interface 84 connected to the processor 83. The processor 83, the memory 82 and the communication interface 84 are connected via a bus 81.

[0055] The processor 83 may be a central processing unit 83 (CPU), a general processor 83, a network processor 83 (NP), a digital signal processor 83 (DSP), a microprocessor 83, a microcontroller, a programmable logic device (PLD), or any combination thereof. The processor 83 may also be any other device having a processing function, such as a circuit, a device, or a software module. The processor 83 may also include multiple CPUs, and the processor 83 may be a single-CPU processor 83 or a multi-CPU processor 83. The processor 83 here may refer to one or more devices, circuits, or processing cores for processing data (such as computer program instructions).

[0056] The memory 82 may be a read-only memory 82 (ROM) or other types of static storage devices that can store static information and instructions, a random access memory 82 (RAM) or other types of dynamic storage devices that can store information and instructions, or an electrically erasable programmable read-only memory 82 (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of an instruction or data structure and can be accessed by a computer, and the embodiment of the present application does not impose any restrictions on this. The memory 82 may exist independently or be integrated with the processor 83. Among them, the memory 82 may contain a computer program code. The processor 83 is used to execute the computer program code stored in the memory 82, so as to realize the control method of the PFC circuit of the air conditioner provided in the embodiment of the present application.

[0057] The communication interface 84 can be used to communicate with other devices or communication networks (such as Ethernet, radio access network (RAN), wireless local area networks (WLAN), etc. The communication interface 84 can be a module, a circuit, a transceiver or any device that can achieve communication.

[0058] The bus 81 may be a peripheral component interconnect (PCI) bus 81 or an extended industry standard architecture (EISA) bus 81, etc. The bus 81 may be divided into an address bus 81, a data bus 81, a control bus 81, etc. For ease of representation, Figure 2 Although only one thick line is used in the figure, it does not mean that there is only one bus 81 or only one type of bus 81.

[0059] Combine the following Figure 1-Figure 6 An air conditioner 100 according to an embodiment of the present invention is described. The air conditioner 100 is used in a PFC circuit.

[0060] like Figure 3 As shown, the air conditioner 100 of the embodiment of the present invention includes: a plurality of PFC channels 101 arranged in parallel, an IGBT switch tube 102, a temperature monitoring module 103 and a controller 71, wherein the plurality of PFC channels 101 arranged in parallel are used to correct the input current waveform of the air conditioner 100; the IGBT switch tube 102 is arranged in each PFC channel 101, and is used to turn on or off the PFC channel 101; the temperature monitoring module 103 is used to monitor the actual temperature value of each IGBT switch tube 102.

[0061] The controller 71 is configured to: after the PFC circuit is started, control the multiple PFC channels 101 to operate at the same current; when the multiple PFC channels 101 operate at the same current, obtain the actual temperature values ​​of the IGBT switch tubes 102 in the multiple PFC channels 101; determine the target current distribution coefficients of the multiple PFC channels 101 according to the actual temperature values; and adjust the current values ​​of the PFC channels 101 according to the target current distribution coefficients until the actual temperature values ​​of the multiple IGBT switch tubes 102 are consistent.

[0062] In an embodiment, after the PFC circuit is started, the controller controls the multiple PFC channels to operate with the same current, i.e., current sharing control, to ensure that the currents of the multiple PFC channels of the PFC circuit remain balanced; when the multiple PFC channels operate with the same current, the temperature monitoring module is controlled to monitor the actual temperature values ​​of the IGBT switch tubes in the multiple PFC channels in real time, for example, recorded as Tn.

[0063] After determining the actual temperature value Tn of the IGBT switch tubes in the multiple PFC channels, the target current distribution coefficients of the multiple PFC channels are adjusted in real time according to the actual temperature value Tn, for example, recorded as Rn, so as to reasonably distribute the current values ​​of the multiple PFC channels according to the target current distribution coefficient Rn, and the current value of the corresponding PFC channel is adjusted in real time, for example, recorded as Iacn, and the on or off time of the IGBT switch tube is controlled according to the current value Iacn of the corresponding PFC channel until the actual temperature values ​​of the multiple IGBT switch tubes are consistent, so as to achieve temperature balance control of the IGBT switch tubes of each PFC channel, avoid damage to the PFC circuit due to excessive temperature of the IGBT switch tube of one of the PFC channels, thereby improving the stability and reliability of the operation of the PFC circuit.

[0064] like Figure 4 and Figure 5 As shown, the air conditioner 100 is provided with three PFC channels in parallel, and an IGBT switch tube is provided on each PFC channel, for example, IGBT1 switch tube, IGBT2 switch tube and IGBT3 switch tube. After the controller controls the three PFC channels to operate at the same current, the temperature monitoring module is controlled to monitor in real time the actual temperature value of the IGBT1 switch tube, for example, T1, the actual temperature value of the IGBT2 switch tube, for example, T2, and the actual temperature value of the IGBT3 switch tube, for example, T3; the target current distribution coefficient R1 is adjusted in real time according to the actual temperature value T1, the target current distribution coefficient R2 is adjusted in real time according to the actual temperature value T2, and the target current distribution coefficient R3 is adjusted in real time according to the actual temperature value T3. R3; adjust the current value Iac1 of the PFC channel in real time according to the target current distribution coefficient R1, adjust the current value Iac2 of the PFC channel in real time according to the target current distribution coefficient R2, and adjust the current value Iac3 of the PFC channel in real time according to the target current distribution coefficient R3, so as to control the on or off time of the IGBT1 switch tube according to the current value Iac1, control the on or off time of the IGBT2 switch tube according to the current value Iac2, and control the on or off time of the IGBT3 switch tube according to the current value Iac3, until the actual temperature value T1 of the IGBT1 switch tube, the actual temperature value T2 of the IGBT2 switch tube and the actual temperature value T3 of the IGBT3 switch tube remain consistent.

[0065] According to the air conditioner 100 of the embodiment of the present invention, the actual temperature value of the IGBT switch tube is monitored to determine the target current distribution coefficient of each PFC channel corresponding thereto, and the current value of the corresponding PFC channel is reasonably distributed according to the target current distribution coefficient, so that the temperature value of the IGBT switch tube is adjusted according to the distributed current value, so that the actual temperature value of the IGBT switch tube tends to be consistent. Therefore, by determining the target current distribution coefficient corresponding to the actual temperature value, the current value of the PFC channel is adjusted to achieve temperature balance control of the IGBT switch tubes of multiple PFC channels, avoid the situation where the temperature of one of the IGBT switch tubes of the multiple PFC channels is too high, resulting in damage to the PFC circuit, thereby improving the stability and reliability of the operation of the PFC circuit.

[0066] In some embodiments, when adjusting the current value of the PFC channel according to the target current distribution coefficient, the controller is configured to: obtain the target total current value of the PFC circuit; calculate the product of the target total current value and the target current distribution coefficient of the PFC channel to obtain the target current value of the corresponding PFC channel; and adjust the current value of the PFC channel to the corresponding target current value.

[0067] In an embodiment, when multiple PFC channels operate at the same current, the controller obtains a bus target voltage value of the PFC circuit, for example, recorded as Vdc_ref and an actual voltage value, for example, recorded as Vdc, and calculates a voltage error between the target voltage value Vdc_ref and the actual voltage value Vdc. The voltage controller performs PI (proportional, integral) voltage control on the target voltage value Vdc_ref and the actual voltage value Vdc according to the voltage error to obtain an output current value, and calculates the product of the output current value and the absolute value of the supply voltage value Vac, i.e., |Vac|, and uses the product as the target total current value, for example, recorded as Iac_ref.

[0068] After obtaining the target total current value Iac_ref of the PFC circuit, the product of the target total current value Iac_ref and the target current distribution coefficient Rn of the PFC channel is calculated respectively, and the target current value Iacn_ref of the corresponding PFC channel is obtained accordingly. The current difference between the target current value Iacn_ref and the actual current value Iac_ref is calculated respectively, and the current controller of each channel performs PI current control on the target current value Iacn_ref and the actual current value Iac_ref according to the current difference, and adjusts the current value of the PFC channel to the corresponding target current value. By determining the target current value Iacn_ref of each PFC channel, the current of the channel can be reasonably distributed according to the target current value Iacn_ref of each PFC channel.

[0069] by Figure 4For example, the PFC circuit sets three PFC channels in parallel, and the target current distribution coefficients include R1, R2 and R3. The products of the target total current value Iac_ref and the target current distribution coefficients R1, R2 and R3 are calculated respectively, and the target current values ​​Iac1_ref, Iac2_ref and Iac3_ref of the corresponding PFC channels are obtained, that is, Iac1_ref=R1×Iac_ref, Iac2_ref=R2×Iac_ref, Iac3_ref=R3×Iac_ref. The current controller 1 is based on the current error Iac 1_ref-Iac1 performs PI current control, and adjusts the current value Iac1 of the PFC channel in real time until it reaches the corresponding target current value Iac1_ref; current controller 2 performs PI current control according to the current error Iac2_ref-Iac2, and adjusts the current value Iac2 of the PFC channel in real time until it reaches the corresponding target current value Iac2_ref; current controller 3 performs PI current control according to the current error Iac3_ref-Iac3, and adjusts the current value Iac3 of the PFC channel in real time until it reaches the corresponding target current value Iac3_ref.

[0070] In some embodiments, when determining the target current distribution coefficient according to the actual temperature value, the target current distribution coefficient is obtained by the following formula:

[0071] Rn=(1 / Tn) / (1 / T1+1 / T2+1 / T3+…+1 / TN);

[0072] Wherein, N is the number of PFC channels, N is an integer greater than 1, n is the current PFC channel, Rn is the target current distribution coefficient of PFC channel n, Tn is the actual temperature value of the IGBT switch tube of PFC channel n, n is a positive integer and n is less than or equal to N, and R1+R2+R3+…Rn=1.

[0073] In the embodiment, after determining the actual temperature value Tn of the IGBT switch tubes in the multiple PFC channels 11, the actual temperature value Tn is substituted into the calculation formula of the target current distribution coefficient Rn to obtain the target current distribution coefficient Rn:

[0074] Rn=(1 / Tn) / (1 / T1+1 / T2+1 / T3+…+1 / TN);

[0075] by Figure 4 For example, the number of PFC channels N = 3, the actual temperature value of IGBT1 is T1, the actual temperature value of IGBT2 is T2, and the actual temperature value of IGBT3 is T3. The calculation formula is as follows:

[0076] R1=(1 / T1) / (1 / T1+1 / T2+1 / T3);

[0077] R2=(1 / T2) / (1 / T1+1 / T2+1 / T3);

[0078] R3=(1 / T3) / (1 / T1+1 / T2+1 / T3);

[0079] And R1+R2+R3=1.

[0080] Under the condition that the target total current value Iac_ref of the PFC circuit remains unchanged, the current value Iacn of each channel is reasonably distributed by allocating the target current distribution coefficients R1, R2 and R3.

[0081] In some embodiments, before adjusting the current value of the PFC channel according to the target current distribution coefficient, the controller is further configured to: determine whether the PFC circuit runs to a stable state; if the PFC circuit runs to a stable state, perform an action of adjusting the current value of the PFC channel according to the actual temperature value of the IGBT switch tube; if the PFC circuit does not run to a stable state, temporarily do not perform the action of adjusting the current value of the PFC channel according to the actual temperature value of the IGBT switch tube, until the PFC circuit runs to a stable state, and then perform the action of adjusting the current value of the PFC channel according to the actual temperature value of the IGBT switch tube.

[0082] In the embodiment, before adjusting the current value of the PFC channel according to the target current distribution coefficient, it is first determined whether the PFC circuit runs to a stable state. If the PFC circuit runs to a stable state, an action of adjusting the current value of the PFC channel according to the actual temperature value Tn of the IGBT switch tube is executed; if the PFC circuit does not run to a stable state, the action of adjusting the current value of the PFC channel according to the actual temperature value Tn of the IGBT switch tube is not executed temporarily until the PFC circuit runs to a stable state, and then the action of adjusting the current value of the PFC channel according to the actual temperature value Tn of the IGBT switch tube is executed, so as to fully ensure the stability of the PFC circuit.

[0083] In some embodiments, when it is determined that the actual temperature value of the IGBT switch tube is continuously and stably within a set temperature range within a set time period, it is determined that the PFC circuit has run into a stable state.

[0084] In the embodiment, since the actual temperature value Tn of the IGBT switch tube usually changes very slowly, it is necessary to wait until the system operation is stable before adjusting the target current distribution coefficient Rn. Therefore, whether the PFC circuit has run into a stable state is judged based on whether the actual temperature value Tn of the IGBT switch tube is stable. When the actual temperature value Tn of the IGBT switch tube is continuously and stably within the set temperature range within the set time period, it is considered that the actual temperature value Tn of the IGBT switch tube is relatively stable, and it is determined that the PFC circuit has run into a stable state; when the actual temperature value Tn of the IGBT switch tube is not continuously and stably within the set temperature range within the set time period, it is considered that the actual temperature value Tn of the IGBT switch tube changes greatly, and it is determined that the PFC circuit has not run into a stable state.

[0085] In some embodiments, when controlling multiple PFC channels to operate with the same current, the controller is configured to: divide the target total current value of the PFC circuit according to the number of PFC channels to obtain an equal current; and control each PFC channel to operate with the equal current.

[0086] In an embodiment, after the PFC circuit is started, the controller determines the number of PFC channels and divides the target total current value Iac_ref of the PFC circuit according to the number of PFC channels to obtain a shared current, thereby controlling each PFC channel to operate with the shared current.

[0087] like Figure 4 and Figure 5 As shown, the number of PFC channels N=3, the target total current value Iac_ref of the PFC circuit is evenly divided to obtain an evenly divided current, ie, Iac1=Iac2=Iac3=Iac_ref / 3, and the three PFC channels are controlled to operate with the above evenly divided current.

[0088] In some embodiments, when determining the target current distribution coefficients of multiple PFC channels according to the actual temperature value, if the actual temperature value of the IGBT switch tube is larger, the corresponding target current distribution coefficient is smaller; if the actual temperature value of the IGBT switch tube is smaller, the corresponding target current distribution coefficient is larger.

[0089] In an embodiment, after determining the actual temperature value Tn of the IGBT switch tubes in multiple PFC channels, the target current distribution coefficients Rn of the multiple PFC channels are adjusted in real time according to the actual temperature value Tn. If the actual temperature value of the IGBT switch tube is larger, the corresponding target current distribution coefficient Rn is smaller; if the actual temperature value of the IGBT switch tube is smaller, the corresponding target current distribution coefficient Rn is larger, thereby achieving temperature balance of each IGBT switch tube of multiple PFC channels.

[0090] In some embodiments, when adjusting the current value of the PFC channel to the corresponding target current value, the controller is further configured to: determine the PWM modulation pulses corresponding to the target current values ​​of multiple PFC channels; and control the on or off time of the IGBT switch tube according to the PWM modulation pulse to adjust the current value of the PFC channel.

[0091] In an embodiment, after the current controller of each channel performs PI current control on the target current value Iacn_ref and the actual current value Iac_ref according to the current difference, the current error output by the current controller of each channel is compensated according to the grid voltage Vac. For example, the current error output by the current controller of each channel is compensated according to the absolute value |Vac| of the grid voltage Vac and the compensation coefficient k to determine the duty cycle of multiple channels, for example, recorded as dn. After comparing the duty cycle dn of the multiple channels with the carrier, the corresponding PWM modulation pulse is determined, for example, recorded as PWMn. The on or off time of the IGBT switch tube is controlled according to the PWM modulation pulse PWMn, and the current value of the PFC channel is adjusted in real time to achieve the consistency of the actual temperature values ​​of each IGBT switch tube of the multiple PFC channels, thereby improving the reliability of the PFC circuit.

[0092] by Figure 4 and Figure 5 For example, the grid voltage Vac compensates the current error Iac1_ref-Iac1 output by the current controller 1, determines the corresponding duty cycle d1, and compares the duty cycle d1 with the carrier to determine the corresponding PWM modulation pulse PWM1. According to PWM1, the on or off time of the IGBT1 switch is controlled to adjust the current value Iac1 of the PFC channel; the grid voltage Vac compensates the current error Iac2_ref-Iac2 output by the current controller 2, determines the corresponding duty cycle d2, and compares the duty cycle d2 with the carrier to determine the corresponding PWM modulation pulse PWM2. According to PWM2, I The on or off time of the GBT2 switch tube is used to adjust the current value Iac2 of the PFC channel; the grid voltage Vac compensates the current error Iac3_ref-Iac3 output by the current controller 3, and determines the corresponding duty cycle d3. After comparing the duty cycle d3 with the carrier, the corresponding PWM modulation pulse is determined to be PWM3. The on or off time of the IGBT3 switch tube is controlled according to the PWM modulation pulse PWM3, and the current value Iac3 of the PFC channel is adjusted to ensure that the actual temperature value T1 of the IGBT1 switch tube, the actual temperature value T2 of the IGBT2 switch tube and the actual temperature value T3 of the IGBT3 switch tube are consistent.

[0093] Reference below Figure 6 The control method of the PFC circuit of the air conditioner according to the embodiment of the present invention is described by way of example.

[0094] like Figure 6 As shown, the control method of the PFC circuit of the air conditioner according to the embodiment of the present invention at least includes steps S11 to S24.

[0095] Step S11, the PFC circuit is started.

[0096] Step S12, dividing the target total current value of the PFC circuit according to the number of PFC channels to obtain an evenly distributed current; and controlling each PFC channel to operate with the evenly distributed current.

[0097] Step S13, obtaining actual temperature values ​​of IGBT switch tubes in multiple PFC channels.

[0098] Step S14: If the actual temperature value of the IGBT switch tube is smaller, the corresponding target current distribution coefficient is larger.

[0099] Step S15: If the actual temperature value of the IGBT switch tube is larger, the corresponding target current distribution coefficient is smaller.

[0100] Step S16, determining whether the actual temperature value of the IGBT switch tube is continuously and stably within the set temperature range within the set time period, if so, executing step S17; otherwise, executing step S18.

[0101] Step S17, determining that the PFC circuit has run to a stable state.

[0102] Step S18: The PFC circuit does not run to a stable state.

[0103] Step S19: temporarily not executing the action of adjusting the current value of the PFC channel according to the actual temperature value of the IGBT switch tube.

[0104] Step S20, executing an action of adjusting the current value of the PFC channel according to the actual temperature value of the IGBT switch tube.

[0105] Step S21, obtaining a target total current value of the PFC circuit.

[0106] Step S22, calculating the product of the target total current value and the target current distribution coefficient of the PFC channel, and obtaining the target current value of the corresponding PFC channel.

[0107] Step S23, determining PWM modulation pulses corresponding to target current values ​​of multiple PFC channels.

[0108] Step S24, controlling the on or off time of the IGBT switch tube according to the PWM modulation pulse to adjust the current value of the PFC channel.

[0109] According to the air conditioner 100 of the embodiment of the present invention, the actual temperature value of the IGBT switch tube is monitored to determine the target current distribution coefficient of each PFC channel corresponding thereto, and the current value of the corresponding PFC channel is reasonably distributed according to the target current distribution coefficient, so that the temperature value of the IGBT switch tube is adjusted according to the distributed current value, so that the actual temperature value of the IGBT switch tube tends to be consistent. Therefore, by determining the target current distribution coefficient corresponding to the actual temperature value, the current value of the PFC channel is adjusted to achieve temperature balance control of the IGBT switch tubes of multiple PFC channels, avoid the situation where the temperature of one of the IGBT switch tubes of the multiple PFC channels is too high, resulting in damage to the PFC circuit, thereby improving the stability and reliability of the operation of the PFC circuit.

[0110] Combine the following Figure 7 The control method of the PFC circuit according to the embodiment of the present invention is described by way of example.

[0111] like Figure 7 As shown, the control method of the PFC circuit of the embodiment of the present invention is used for an air conditioner, and the method at least includes steps S1 to S4.

[0112] Step S1, after the PFC circuit is started, controlling multiple PFC channels to operate with the same current.

[0113] In an embodiment, after the PFC circuit is started, the multiple PFC channels are controlled to operate with the same current, that is, current sharing control is performed to ensure that the currents of the multiple PFC channels of the PFC circuit remain balanced.

[0114] Step S2, when the multiple PFC channels are running at the same current, obtaining the initial current distribution coefficients of the multiple PFC channels and the actual temperature values ​​of the IGBT switch tubes.

[0115] In an embodiment, when multiple PFC channels are running at the same current, the temperature monitoring module is controlled to monitor the actual temperature values ​​of the IGBT switch tubes in the multiple PFC channels in real time, for example, recorded as Tn.

[0116] Step S3, adjusting the initial current distribution coefficient according to the actual temperature value to obtain the target current distribution coefficient.

[0117] In an embodiment, after determining the actual temperature value Tn of the IGBT switch tubes in multiple PFC channels, the target current distribution coefficients of the multiple PFC channels are adjusted in real time according to the actual temperature value Tn, for example, recorded as Rn, so as to reasonably distribute the current values ​​of the multiple PFC channels according to the target current distribution coefficient Rn.

[0118] Step S4, adjusting the current value of the PFC channel according to the target current distribution coefficient until the actual temperature values ​​of the multiple IGBT switch tubes are consistent.

[0119] In an embodiment, after determining the target current distribution coefficient Rn, the current value of the corresponding PFC channel is adjusted in real time according to the target current distribution coefficient Rn, for example, recorded as Iacn, and the on or off time of the IGBT switch tube is controlled according to the current value Iacn of the corresponding PFC channel until the actual temperature values ​​of the multiple IGBT switch tubes are consistent, thereby achieving temperature balance control of the IGBT switch tubes of each PFC channel, avoiding damage to the PFC circuit due to excessive temperature of the IGBT switch tube of one of the PFC channels, thereby improving the stability and reliability of the operation of the PFC circuit.

[0120] According to the control method of the PFC circuit of the embodiment of the present invention, by monitoring the actual temperature value of the IGBT switch tube, the target current distribution coefficient of each PFC channel corresponding thereto is determined, and the current value of the corresponding PFC channel is reasonably distributed according to the target current distribution coefficient, so that the temperature value of the IGBT switch tube is adjusted according to the distributed current value, so that the actual temperature value of the IGBT switch tube tends to be consistent. Therefore, by determining the target current distribution coefficient corresponding to the actual temperature value, the current value of the PFC channel is adjusted, and the temperature balance control of the IGBT switch tubes of multiple PFC channels is realized, so that the damage of the PFC circuit caused by the excessive temperature of one of the IGBT switch tubes of the multiple PFC channels is avoided, thereby improving the stability and reliability of the operation of the PFC circuit.

[0121] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0122] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. An air conditioner, characterized in that: For a PFC circuit, the air conditioner comprises: A plurality of PFC channels arranged in parallel are used to correct the input current waveform of the air conditioner; An IGBT switch tube is arranged in each of the PFC channels and is used to turn on or off the PFC channel; A temperature monitoring module is used to monitor the actual temperature value of each IGBT switch tube; The controller is configured as: After the PFC circuit is started, controlling the plurality of PFC channels to operate with the same current; When the multiple PFC channels are running at the same current, obtaining actual temperature values ​​of the IGBT switch tubes in the multiple PFC channels; Determine a target current distribution coefficient of the plurality of PFC channels according to the actual temperature value; The current value of the PFC channel is adjusted according to the target current distribution coefficient until the actual temperature values ​​of the multiple IGBT switch tubes are consistent.

2. The air conditioner according to claim 1, characterized in that: When adjusting the current value of the PFC channel according to the target current distribution coefficient, the controller is configured as follows: Obtaining a target total current value of the PFC circuit; Calculate the product of the target total current value and the target current distribution coefficient of the PFC channel to obtain the target current value of the corresponding PFC channel; The current values ​​of the PFC channels are adjusted to the corresponding target current values.

3. The air conditioner according to claim 1, characterized in that: When determining the target current distribution coefficient according to the actual temperature value, the target current distribution coefficient is obtained by the following formula: Rn=(1 / Tn) / (1 / T1+1 / T2+1 / T3+…+1 / TN); Among them, N is the number of the PFC channels, N is an integer greater than 1, n is the current PFC channel, Rn is the target current distribution coefficient of PFC channel n, Tn is the actual temperature value of the IGBT switch tube of PFC channel n, n is a positive integer and n is less than or equal to N, and R1+R2+R3+…Rn=1.

4. The air conditioner according to claim 1, characterized in that: Before adjusting the current value of the PFC channel according to the target current distribution coefficient, the controller is further configured to: Determining whether the PFC circuit operates to a stable state; If the PFC circuit runs to a stable state, an action of adjusting the current value of the PFC channel according to the actual temperature value of the IGBT switch tube is performed; If the PFC circuit has not run to a stable state, the action of adjusting the current value of the PFC channel according to the actual temperature value of the IGBT switch tube will not be performed temporarily until the PFC circuit runs to a stable state, and then the action of adjusting the current value of the PFC channel according to the actual temperature value of the IGBT switch tube will be performed.

5. The air conditioner according to claim 1, characterized in that: The controller is specifically configured as follows: When it is determined that the actual temperature value of the IGBT switch tube is continuously and stably within the set temperature range within the set time period, it is determined that the PFC circuit has run to a stable state.

6. The air conditioner according to claim 2, characterized in that: When controlling the plurality of PFC channels to operate at the same current, the controller is configured as follows: Dividing the target total current value of the PFC circuit equally according to the number of the PFC channels to obtain an equally divided current; Each of the PFC channels is controlled to operate with the shared current.

7. The air conditioner according to claim 1, characterized in that: When determining the target current distribution coefficients of the plurality of PFC channels according to the actual temperature value, if the actual temperature value of the IGBT switch tube is larger, the corresponding target current distribution coefficient is smaller.

8. The air conditioner according to claim 1, characterized in that: When determining the target current distribution coefficients of the plurality of PFC channels according to the actual temperature value, if the actual temperature value of the IGBT switch tube is smaller, the corresponding target current distribution coefficient is larger.

9. The air conditioner according to claim 2, characterized in that: When adjusting the current value of the PFC channel to the corresponding target current value, the controller is further configured to: Determine PWM modulation pulses corresponding to target current values ​​of a plurality of PFC channels; The on or off time of the IGBT switch tube is controlled according to the PWM modulation pulse to adjust the current value of the PFC channel.

10. A control method for a PFC circuit, characterized in that: For an air conditioner, the method comprises: After the PFC circuit starts, multiple PFC channels are controlled to operate with the same current; When the multiple PFC channels are running at the same current, obtaining the initial current distribution coefficients of the multiple PFC channels and the actual temperature value of the IGBT switch tube; Adjust the initial current distribution coefficient according to the actual temperature value to obtain a target current distribution coefficient; The current value of the PFC channel is adjusted according to the target current distribution coefficient until the actual temperature values ​​of the multiple IGBT switch tubes are consistent.

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