Air conditioner

Abstract

The air conditioner comprises a refrigerant circulation loop, a condensation temperature sensor, a PFC circuit and a controller, and the controller is configured to obtain the current effective value, the voltage peak value, the condensation temperature, the compressor operation frequency and the actual bus voltage value of alternating current input voltage; determining a bus coefficient according to the current effective value and the voltage peak value, or determining a target coefficient according to the current effective value, the voltage peak value, the condensation temperature and the compressor operation frequency; determining a target bus voltage value according to the product of the voltage peak value and the target coefficient; and generating a voltage control instruction according to the target bus voltage value and the actual bus voltage value, and outputting the voltage control instruction to the PFC circuit, so that the PFC circuit controls the on-off state of an internal switching tube based on the voltage control instruction, and the actual bus voltage value reaches the target bus voltage value. The overhigh bus voltage caused by the adoption of the fixed bus voltage under the condition of light load or high input voltage is avoided, and unnecessary switching loss is inhibited.

Description

Technical Field

[0001] This invention relates to the field of air conditioner technology, and in particular to an air conditioner. Background Technology

[0002] In existing technologies, PFC (Power Factor Correction) control typically sets the target value of the bus voltage slightly higher than the peak value of the AC input voltage to ensure that the PFC circuit operates effectively throughout the entire AC input cycle, thereby maintaining a high power factor and suppressing current harmonics. However, when the system is under light load or the input voltage is low, maintaining a high bus voltage can lead to a significant increase in switching losses and reduce system efficiency.

[0003] To address the aforementioned issues, existing technical solutions propose adjusting the input bus voltage based on the output DC voltage to ensure a certain proportional relationship between the output DC voltage and the bus voltage. However, this control method is only applicable to DC-to-DC conversion scenarios and cannot be directly applied to systems such as air conditioners that require DC to AC conversion. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. Therefore, the object of the present invention is to provide an air conditioner.

[0005] The present invention provides an air conditioner comprising: The refrigerant circulation loop allows the refrigerant to circulate in a loop consisting of a compressor, condenser, expansion valve, and evaporator. One of the condensers and the other of the evaporator is an outdoor heat exchanger and the other is an indoor heat exchanger. A condensation temperature sensor is used to obtain the condensation temperature of the outdoor heat exchanger; The PFC circuit is used to correct the power factor of the AC input voltage and to regulate the actual bus voltage value by controlling the on / off state of its internal switching transistors. The controller is configured to: Obtain the effective value of the current, the peak value of the voltage, the condensing temperature, the compressor operating frequency, and the actual bus voltage value of the AC input voltage; The target coefficient is determined based on the effective value of the current and the peak value of the voltage, or the target coefficient is determined based on the effective value of the current, the peak value of the voltage, the condensing temperature and the compressor operating frequency; The target bus voltage value is determined by multiplying the peak voltage value and the target coefficient. A voltage control command is generated based on the target bus voltage value and the actual bus voltage value, and the voltage control command is output to the PFC circuit so that the PFC circuit controls the on / off state of its internal switching transistors based on the voltage control command, so that the actual bus voltage value reaches the target bus voltage value. The voltage control command is used to characterize the amount of voltage regulation applied to the PFC circuit required for the actual bus voltage value to reach the target bus voltage value.

[0006] According to the air conditioner of the present invention, by acquiring the effective value of the current, the peak value of the voltage, the condensing temperature, and the compressor operating frequency of the AC input voltage, the target coefficient can be determined based on the effective value of the current and the peak value of the voltage, or the target coefficient can be determined based on the effective value of the current, the peak value of the voltage, the condensing temperature, and the compressor operating frequency. This allows the air conditioner to flexibly select the balance point between control accuracy and response speed according to the actual operating state. The target bus voltage value is then calculated based on the product of the determined target coefficient and the peak voltage. The voltage control command generated based on the target bus voltage value and the actual bus voltage value is transmitted to the PFC circuit to adjust the on / off state of the internal switching transistors of the PFC circuit. This allows the actual bus voltage value to quickly and smoothly approach and stabilize at the target bus voltage value. This ensures the reliable operation of the downstream inverter and compressor while achieving synergistic optimization of high power factor, low harmonic distortion, and high energy efficiency. It overcomes the problem that traditional methods are only applicable to DC-DC conversion scenarios and cannot be directly applied to systems such as air conditioners that require DC to AC conversion. By dynamically adjusting the target coefficient according to the operating conditions, it avoids the problem of excessively high bus voltage caused by using a fixed bus voltage under light load or high input voltage conditions. This effectively suppresses unnecessary switching losses, reduces the overall power consumption of the system, and improves operating efficiency.

[0007] In addition, the air conditioner according to embodiments of the present invention may also have the following additional technical features: Furthermore, when determining the target coefficient based on the effective current value and the peak voltage value, or when determining the target coefficient based on the effective current value, the peak voltage value, the condensing temperature, and the compressor operating frequency, the controller is configured to: switch the air conditioner from the current PFC control mode to the target PFC control mode based on the effective current value and the peak voltage value, or switch the air conditioner from the current PFC control mode to the target PFC control mode based on the peak voltage value, the condensing temperature, and the compressor operating frequency, and determine the target coefficient corresponding to the target PFC control mode based on the effective current value.

[0008] The above technical solution has the following advantages or beneficial effects: it not only improves the overall energy efficiency, but also takes into account the power factor correction performance and electromagnetic compatibility, avoiding the problem of low efficiency of traditional fixed bus voltage solutions over a wide operating range.

[0009] Furthermore, when switching the air conditioner from the current PFC control mode to the target PFC control mode based on the voltage peak value, the condensing temperature, and the compressor operating frequency, the controller is configured to: switch the air conditioner from the current PFC control mode to the first PFC control mode when the condensing temperature is less than a preset condensing temperature threshold, the compressor operating frequency is less than a preset compressor operating frequency threshold, and the voltage peak value is greater than a preset voltage threshold.

[0010] The above technical solution has the following advantages or beneficial effects: it can significantly improve system efficiency while ensuring basic power quality.

[0011] Furthermore, when switching the air conditioner from the current PFC control mode to the target PFC control mode based on the voltage peak value, the condensing temperature, and the compressor operating frequency, the controller is also configured to: switch the air conditioner from the current PFC control mode to the second PFC control mode when the condensing temperature is greater than or equal to the preset condensing temperature threshold, and / or the compressor operating frequency is greater than or equal to the preset compressor operating frequency threshold, and / or the voltage peak value is less than or equal to the preset voltage threshold.

[0012] The above technical solutions have the following advantages or beneficial effects: improving the system's dynamic response capability and load-bearing capacity, and ensuring the stable and efficient operation of the whole machine under harsh conditions such as heavy load, high temperature or low voltage.

[0013] Furthermore, when switching the air conditioner from the current PFC control mode to the target PFC control mode based on the effective current value and the peak voltage value, the controller is configured to: switch the air conditioner from the current PFC control mode to the first PFC control mode when the effective current value is less than a preset current threshold and the peak voltage value is greater than a preset voltage threshold.

[0014] The above technical solution has the following advantages or beneficial effects: it reduces the conduction loss and switching loss of the switching transistor, significantly improves the system's operating efficiency under light load and high input voltage conditions while ensuring basic power quality, and achieves energy-saving optimization.

[0015] Furthermore, when switching the air conditioner from the current PFC control mode to the target PFC control mode based on the effective current value and the peak voltage value, the controller is also configured to: switch the air conditioner from the current PFC control mode to the second PFC control mode when the effective current value is greater than or equal to the preset current threshold and / or the peak voltage value is less than or equal to the preset voltage threshold.

[0016] The above technical solution has the following advantages or beneficial effects: it ensures that the inverter can reliably drive the compressor and maintains power quality with high power factor and low harmonic distortion, thereby effectively balancing the performance requirements and operational reliability of the system under harsh conditions such as heavy load and low voltage.

[0017] Furthermore, when determining the target coefficient corresponding to the target PFC control mode based on the effective value of the current, the controller is configured to: when the air conditioner switches from the current PFC control mode to the first PFC control mode, query a first preset lookup table based on the effective value of the current to determine the first target coefficient, wherein the first preset lookup table includes multiple sets of correspondences between effective values ​​of current and the first target coefficient, and the first target coefficient increases as the effective value of the current increases.

[0018] The above technical solution has the following advantages or beneficial effects: the controller can quickly and accurately obtain the first target coefficient based on the current effective value of the current, and calculate a reasonable target bus voltage in combination with the voltage peak value, thereby achieving a dynamic balance between efficiency and performance in the first PFC control mode.

[0019] Furthermore, when determining the target coefficient corresponding to the target PFC control mode based on the effective value of the current, the controller is also configured to: when the air conditioner switches from the current PFC control mode to the second PFC control mode, query a second preset lookup table based on the effective value of the current to determine the second target coefficient, wherein the second preset lookup table includes multiple sets of correspondences between effective values ​​of current and the second target coefficient, the second target coefficient increases as the effective value of the current increases, and the second target coefficient is greater than the first target coefficient.

[0020] The above technical solution has the following advantages or beneficial effects: it can accurately match the optimal target bus voltage under different operating scenarios, and maximize overall energy efficiency while taking into account system reliability.

[0021] Furthermore, when generating a voltage control command based on the target bus voltage value and the actual bus voltage value, the controller is configured to: determine the voltage deviation value between the target bus voltage value and the actual bus voltage value; and generate the voltage control command based on the voltage deviation value.

[0022] The above technical solution has the following advantages or beneficial effects: it can continuously and dynamically correct the actual bus voltage, ensuring that it stably tracks the target bus voltage, thereby providing a reliable and high-quality DC power supply for the downstream inverter.

[0023] Furthermore, when switching the air conditioner from the current PFC control mode to the target PFC control mode, the controller is configured to: control the target bus voltage value corresponding to the current PFC control mode to smoothly transition to the target bus voltage value corresponding to the target PFC control mode according to a preset ramp rate.

[0024] The above technical solution has the following advantages or beneficial effects: it not only effectively suppresses voltage oscillations, current spikes and electromagnetic interference that may occur during mode switching, but also significantly improves the stability and reliability of system operation, so that the switching process of PFC control mode is completed without the user's notice, taking into account both energy efficiency optimization and dynamics.

[0025] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0026] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the structure of an air conditioner according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the controller according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of an air conditioner according to another embodiment of the present invention; Figure 4 This is a schematic diagram of a PFC circuit according to an embodiment of the present invention; Figure 5 This is a flowchart of an air conditioner control method according to an embodiment of the present invention; Figure 6 This is a flowchart illustrating the control mode switching of an air conditioner according to an embodiment of the present invention; Figure 7 This is a flowchart of a control mode switching function for an air conditioner according to another embodiment of the present invention. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0029] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] This invention provides an air conditioner 10, with reference to... Figure 1 The air conditioner 10 includes a refrigeration system for exchanging heat with indoor air to meet cooling or heating needs.

[0032] The refrigeration system includes a compressor, a condenser, an electronic expansion valve, and an evaporator. In this invention, the air conditioner 10 performs a refrigeration cycle by using the compressor, condenser, electronic expansion valve, and 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.

[0033] The compressor compresses refrigerant gas under high temperature and pressure 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.

[0034] The electronic expansion valve expands the high-temperature, high-pressure liquid refrigerant condensed in the condenser into a low-pressure liquid refrigerant. The evaporator evaporates the refrigerant that has expanded in the electronic expansion valve and returns the low-temperature, low-pressure refrigerant gas to the compressor.

[0035] The evaporator achieves a cooling effect by utilizing the latent heat of refrigerant evaporation to exchange heat with the material being cooled. Throughout the cycle, the air conditioner 10 can regulate the temperature of the indoor space.

[0036] The outdoor unit 2 of the air conditioner 10 refers to the part of the refrigeration cycle that includes the compressor and the outdoor heat exchanger. The indoor unit 1 of the air conditioner 10 includes the indoor heat exchanger, and an electronic expansion valve can be provided in either the indoor unit 1 or the outdoor unit 2.

[0037] The indoor heat exchanger and the outdoor heat exchanger are used as condensers or evaporators. When the indoor heat exchanger is used as a condenser, the air conditioner 10 is used as a heater in heating mode, and when the indoor heat exchanger is used as an evaporator, the air conditioner 10 is used as a cooler in cooling mode.

[0038] The air conditioner 10 of this invention includes an indoor unit 1 and an outdoor unit 2, which can be configured as an integrated unit or a split unit. The indoor unit 1 can be configured as a wall-mounted unit, a ceiling-mounted unit, a ducted unit, etc., and the indoor unit 1 is installed on the top of the room.

[0039] Reference Figure 1 Taking indoor wall-mounted units as an example, indoor wall-mounted units are usually installed on indoor walls or other locations. For example, indoor cabinet units (not shown in the figure) are also a type of indoor unit 1.

[0040] Taking a split-type air conditioner as an example, the air conditioner 10 includes an indoor unit 1 and an outdoor unit 2. The outdoor unit 2 is usually installed outdoors and is used for heat exchange in the indoor environment.

[0041] Furthermore, as shown in the figure, the air conditioner 10 includes a controller 71 to control the operation of various components within the air conditioner 10, enabling each component to perform its predetermined functions. The air conditioner 10 also includes a control device 200, which, for example, is a remote control. This remote control has the function of communicating with the controller 71 using, for example, infrared or other communication methods. The remote control allows the user to perform various controls on the air conditioner 10, enabling interaction between the user and the air conditioner 10.

[0042] In this embodiment of the invention, the indoor unit 1 of the air conditioner 10 is located at the top or upper part of the room. Generally, the installation height of the indoor unit 1 is higher than the user's activity area. The indoor unit 1 includes a return air vent and an air outlet that communicate with the room. Indoor air passes through the return air vent into the indoor unit 1 and flows back into the room through the air outlet.

[0043] The refrigerant circulation loop in this invention allows the refrigerant to circulate within a circuit consisting of a compressor, condenser, electronic expansion valve, and evaporator. One of the condenser and evaporator is an outdoor heat exchanger, and the other is an indoor heat exchanger. The indoor heat exchanger exchanges heat with the air inside the indoor unit 1, and the outdoor unit 2 heat exchanger exchanges heat with the air inside the outdoor unit 2, thereby fulfilling the cooling or heating requirements of the air conditioner 10.

[0044] The indoor unit 1 also includes an indoor fan, which is located near the return air vent or the air outlet of the indoor heat exchanger. It is used to deliver the heat-exchanged air to the room. The indoor fan has multiple speed settings to change the airflow speed at the air outlet.

[0045] An air guide plate is installed at the air outlet. By changing its relative rotation angle with the air outlet, the air guide plate adjusts the direction of the airflow through the air outlet, thereby affecting the stratification of indoor air temperature.

[0046] In the embodiment shown in this invention, the air conditioner 10 further includes a controller 71, which is a device that can generate operation control signals according to instruction operation codes and timing signals to instruct the air conditioner 10 to execute control commands. For example, in response to a power-on or power-off command issued by a user, the controller 71 can perform an operation related to the object selected by the power-on or power-off command.

[0047] This invention also provides a hardware structure diagram of the controller 71, as shown in the embodiment. Figure 2 As shown, the controller 71 includes a processor 83, and optionally, a memory 82 and a communication interface 84 connected to the processor 83. The processor 83, memory 82, and communication interface 84 are connected via a bus 81.

[0048] Processor 83 can be a central processing unit (CPU), a general-purpose processor (NP), a network processor (NP), a digital signal processor (DSP), a microprocessor (Microcontroller 718), a programmable logic device (PLD), or any combination thereof. Processor 83 can also be any other device with processing capabilities, such as a circuit, device, or software module. Processor 83 can also include multiple CPUs, and processor 83 can be a single-core processor 83 or a multi-core processor 83. Here, processor 83 can refer to one or more devices, circuits, or processing cores used for processing data (e.g., computer program instructions).

[0049] The memory 82 can be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, a random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD ROM) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer. This embodiment of the invention does not impose any limitations on this. The memory 82 can exist independently or be integrated with the processor 83. The memory 82 may contain computer program code. The processor 83 is used to execute the computer program code stored in the memory 82, thereby implementing the air conditioner control method provided in this embodiment of the invention.

[0050] 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, circuit, transceiver, or any device capable of communication.

[0051] Bus 81 can be a Peripheral Component Interconnect (PCI) bus 81 or an Extended Industry Standard Architecture (EISA) bus 81, etc. Bus 81 can be divided into address bus 81, data bus 81, control bus 81, etc. For ease of representation, Figure 2 The bus is represented by only one thick line, but this does not mean that there is only one bus 81 or one type of bus 81.

[0052] The following is for reference. Figure 3 An air conditioner according to an embodiment of the present invention is described.

[0053] Figure 3 This is a schematic diagram of the structure of an air conditioner according to an embodiment of the present invention. Figure 3 As shown, an air conditioner 10 includes: a refrigerant circulation loop 11, a condensing temperature sensor 12, a PFC circuit 13, and a controller 71.

[0054] The refrigerant circulation loop 11 allows the refrigerant to circulate in a loop consisting of the compressor, condenser, expansion valve, and evaporator. One of the condensers and the other of the evaporator is an outdoor heat exchanger and the other is an indoor heat exchanger. The condensing temperature sensor 12 is used to obtain the condensing temperature of the outdoor heat exchanger. The PFC circuit 13 is used to perform power factor correction on the AC input voltage and to adjust the actual bus voltage value by controlling the on / off state of its internal switching tube.

[0055] In a specific embodiment, such as Figure 4 The schematic diagram of the PFC circuit shown includes a rectifier bridge (composed of diodes D1, D2, D3, and D4), a fast recovery diode D5, an inductor L1, a capacitor C1, a switching transistor Q1, a PFC drive circuit, a current detection unit, and a voltage detection unit.

[0056] The AC power supply first undergoes full-wave rectification through a rectifier bridge composed of diodes D1 to D4, converting the AC voltage into a pulsating DC voltage. This voltage then freewheels through inductor L1. Under the control of controller 71, the PWM duty cycle of switch Q1 is dynamically adjusted according to the input voltage waveform to achieve precise shaping of the input current, making it follow the changes in input voltage and thus improving the power factor. When switch Q1 is turned on, inductor L1 stores energy, and the current rises; when switch Q1 is turned off, inductor L1 freewheels through fast recovery diode D5, transferring energy to output capacitor C1, while simultaneously powering the inverter and motor load. Capacitor C1 is used to filter and smooth the bus voltage, providing a stable DC power supply. The current detection unit and voltage detection unit collect the input current and bus voltage signals in real time and feed them back to controller 71, forming a closed-loop control to ensure that the input current and voltage are in phase, effectively suppressing harmonics and achieving efficient, high-power-factor energy conversion.

[0057] The controller 71 is configured to: acquire the effective current value, peak voltage value, condensing temperature, compressor operating frequency, and actual bus voltage value of the AC input voltage; determine a target coefficient based on the effective current value and peak voltage value, or determine the target coefficient based on the effective current value, peak voltage value, condensing temperature, and compressor operating frequency; determine the target bus voltage value based on the product of the peak voltage value and the target coefficient; generate a voltage control command based on the target bus voltage value and the actual bus voltage value, and output the voltage control command to the PFC circuit, so that the PFC circuit controls the on / off state of its internal switching transistors based on the voltage control command, so that the actual bus voltage value reaches the target bus voltage value. The voltage control command is used to characterize the voltage regulation amount applied to the PFC circuit required for the actual bus voltage value to reach the target bus voltage value.

[0058] In the embodiment, reference Figure 3 and Figure 4 The controller 71 acquires the peak voltage of the AC input voltage (e.g., denoted as Vacpeak) in real time through the voltage detection unit, acquires the effective current value of the AC input voltage (e.g., denoted as Iac) through the current detection unit, and simultaneously acquires the actual bus voltage value through the voltage detection unit, as well as the condensing temperature and compressor operating frequency measured by the condensing temperature sensor 12.

[0059] Based on the effective value of the current, the peak value of the voltage, the condensing temperature, and the compressor operating frequency, the controller 71 can select two methods to determine the target coefficient (e.g., denoted as K).

[0060] Specifically, the target coefficient can be determined based on the effective value of the current and the peak value of the voltage, or it can be determined based on the effective value of the current, the peak value of the voltage, the condensing temperature, and the compressor operating frequency. This allows the air conditioner 10 to flexibly select a balance between control accuracy and response speed according to the operating status. After determining the target coefficient K, the controller 71 calculates the target bus voltage value Vbus_target by multiplying the target coefficient K by the peak voltage Vacpeak, i.e., Vbus_target = K × Vacpeak.

[0061] Subsequently, the controller 71 compares the calculated target bus voltage value Vbus_target with the actual bus voltage value. Based on the comparison result, it determines the voltage regulation amount required for the actual bus voltage value to reach the target bus voltage value. Then, it generates a voltage control command based on the voltage regulation amount. The controller 71 outputs the voltage control command to the PFC drive circuit. The PFC drive circuit generates a PWM (Pulse Width Modulation) signal to control the turn-on and turn-off timing of the switching transistor Q1, that is, to dynamically adjust its duty cycle. For example, when the actual bus voltage is lower than the target bus voltage, the conduction time of the switching transistor Q1 is increased to improve energy transfer efficiency, causing the actual bus voltage to rise. Conversely, the duty cycle is reduced to suppress voltage overshoot. By adjusting the operating state of the PFC circuit, the actual bus voltage can quickly and smoothly approach and stabilize at the target bus voltage. This ensures reliable operation of the downstream inverter and compressor while achieving synergistic optimization of high power factor, low harmonic distortion, and high energy efficiency. It overcomes the problem that traditional methods are only applicable to DC-to-DC conversion scenarios and cannot be directly applied to systems such as air conditioners that require DC to AC conversion. By dynamically adjusting the target coefficient according to the operating conditions, it avoids the problem of excessively high bus voltage caused by using a fixed bus voltage under light load or high input voltage conditions. This effectively suppresses unnecessary switching losses, reduces overall system power consumption, and improves operating efficiency.

[0062] In one embodiment of the present invention, when determining the target coefficient based on the effective value of the current and the peak value of the voltage, or based on the effective value of the current, the peak value of the voltage, the condensing temperature and the compressor operating frequency, the controller 71 is configured to: switch the air conditioner 10 from the current PFC control mode to the target PFC control mode based on the effective value of the current and the peak value of the voltage, or based on the peak value of the voltage, the condensing temperature and the compressor operating frequency; and determine the target coefficient corresponding to the target PFC control mode based on the effective value of the current.

[0063] In the embodiments, the PFC control modes include, for example, a first PFC control mode and a second PFC control mode. The first PFC control mode is a partial PFC control mode, which is suitable for low-power operating conditions such as light load or high input voltage. In this case, the target bus voltage value is set relatively low to reduce switching losses. The second PFC control mode is a full PFC control mode, which is suitable for high-power demand operating conditions such as heavy load or low input voltage. In this case, the target bus voltage value is set relatively high to ensure that the downstream inverter obtains sufficient and stable DC power.

[0064] When determining the target coefficient based on operating parameters, the controller 71 can dynamically switch the PFC control mode according to different combinations of conditions. On the one hand, it can be judged based on the effective value of the current and the peak value of the voltage; on the other hand, it can also be judged by combining the peak voltage, condensing temperature and compressor operating frequency. Once the mode switching is completed, the controller 71 determines the target coefficient K corresponding to the mode according to the current effective value of the current, for example, its value range is [0.7, 1.3].

[0065] For example, when the air conditioner 10 is currently in the first PFC control mode, the controller 71 can control the air conditioner 10 to switch from the first PFC control mode to the second PFC control mode based on the judgment results of the effective current value and the peak voltage value. After the switch is completed, the controller determines the target coefficient corresponding to the second PFC control mode based on the current effective current value. Similarly, when the air conditioner 10 is in the second PFC control mode, if the switching conditions are met based on the judgment results of the effective current value and the peak voltage value, the controller 71 can also switch it back to the first PFC control mode and determine the target coefficient corresponding to the first PFC control mode accordingly based on the effective current value.

[0066] Alternatively, when the air conditioner 10 is currently in the first PFC control mode, the controller 71 can control the air conditioner 10 to switch from the first PFC control mode to the second PFC control mode based on the judgment results of the voltage peak value, condensing temperature, and compressor operating frequency. After the switch is completed, the controller determines the target coefficient corresponding to the second PFC control mode based on the effective value of the current. Similarly, when the air conditioner 10 is in the second PFC control mode, if the switching conditions are met based on the judgment results of the voltage peak value, condensing temperature, and compressor operating frequency, the controller 71 can also switch it back to the first PFC control mode and determine the target coefficient corresponding to the first PFC control mode accordingly based on the effective value of the current.

[0067] Thus, the precise matching between the PFC operating mode and the actual operating conditions of the air conditioner 10 is achieved. That is, the partial PFC control mode is adopted under light load or high input voltage conditions to effectively suppress unnecessary switching losses. Under heavy load or low temperature and high compression ratio conditions, it switches to the full PFC control mode to ensure the stability of the bus voltage and the reliability of the system. Through the adaptive switching of the mode and the refined setting of the target coefficient, not only the energy efficiency of the whole machine is improved, but also the power factor correction performance and electromagnetic compatibility are taken into account, avoiding the problem of low efficiency of the traditional fixed bus voltage scheme in a wide range of operating conditions.

[0068] In an embodiment of the present invention, when switching the air conditioner 10 from the current PFC control mode to the target PFC control mode according to the voltage peak, the condensation temperature, and the compressor operating frequency, the controller 71 is configured to: when the condensation temperature is less than the preset condensation temperature threshold, the compressor operating frequency is less than the preset compressor operating frequency threshold, and the voltage peak is greater than the preset voltage threshold, switch the air conditioner 10 from the current PFC control mode to the first PFC control mode.

[0069] Among them, for example, the condensation temperature is denoted as Tcon, the preset condensation temperature threshold is denoted as Tconth, the compressor operating frequency is denoted as F, the preset compressor operating frequency threshold is denoted as Fth, and the preset voltage threshold is denoted as Vacpeakth.

[0070] In the embodiment, the controller 71 compares the condensation temperature Tcon, the compressor operating frequency F, and the voltage peak Vacpeak with their corresponding preset thresholds respectively, and judges whether to switch the current PFC control mode of the air conditioner 10 according to the comparison results.

[0071] Specifically, when the condensation temperature Tcon is less than the preset condensation temperature threshold Tconth, it indicates that the outdoor heat exchange load is light. When the compressor operating frequency F is less than the preset compressor operating frequency threshold Fth, it means that the system is in a low refrigeration or heating demand state. When the voltage peak Vacpeak is greater than the preset voltage threshold Vacpeakth, it means that the grid input voltage is high and the basic bus voltage after rectification is sufficient to support light load operation. Therefore, when Tcon < Tconth and F < Fth and Vacpeak > Vacpeakth, the overall system load is light and the input energy is sufficient. Continuing to maintain the second PFC control mode (i.e., the full PFC mode) with a high bus voltage will result in unnecessary switching losses. Therefore, the controller 71 determines that the air conditioner 10 should be switched from the current second PFC control mode to the first PFC control mode (i.e., the partial PFC mode), thereby reducing the actual bus voltage and significantly improving the system efficiency on the premise of ensuring the basic power quality.

[0072] In one embodiment of the present invention, when the air conditioner 10 is switched from the current PFC control mode to the target PFC control mode based on the voltage peak value, condensing temperature and compressor operating frequency, the controller 71 is further configured to switch the air conditioner 10 from the current PFC control mode to the second PFC control mode when the condensing temperature is greater than or equal to a preset condensing temperature threshold, and / or the compressor operating frequency is greater than or equal to a preset compressor operating frequency threshold, and / or the voltage peak value is less than or equal to a preset voltage threshold.

[0073] In this embodiment, when the controller 71 makes a comprehensive judgment on the operating status of the air conditioner 10 based on the voltage peak value, condensing temperature, and compressor operating frequency, if it detects any one or more operating condition characteristics that reflect the increased system load or deterioration of input conditions, i.e., satisfying any of the following conditions: the condensing temperature Tcon is greater than or equal to the preset condensing temperature threshold Tconth, i.e., Tcon ≥ Tconth, indicating that the outdoor heat exchanger has difficulty dissipating heat and the system is in a high condensing pressure state; the compressor operating frequency F is greater than or equal to the preset compressor operating frequency threshold Fth, i.e., F ≥ Fth, indicating that the cooling or heating demand has increased and the compressor is operating at a high load; the voltage peak value Vacpeak is less than or equal to the preset voltage threshold Vacpeakth, i.e., Vacpeak ≤ Vacpeakth, meaning that the grid voltage is low and the level of the base bus after rectification is insufficient, as long as at least one of the above three conditions is met, the controller 71 determines that the current operating condition is no longer suitable for continuing to operate in the first PFC control mode with low bus voltage. At this point, to ensure that the downstream inverter can obtain a sufficient and stable DC bus voltage to drive the compressor reliably and maintain a good power factor and current waveform quality, the controller 71 switches the air conditioner 10 from the first PFC control mode to the second PFC control mode. In the second PFC control mode, the target bus voltage is set to a higher level, thereby improving the system's dynamic response and load-carrying capacity, and ensuring stable and efficient operation of the entire unit under harsh conditions such as heavy load, high temperature, or low voltage.

[0074] In one embodiment of the present invention, when the air conditioner 10 is switched from the current PFC control mode to the target PFC control mode based on the effective value of the current and the peak value of the voltage, the controller 71 is configured to switch the air conditioner 10 from the current PFC control mode to the first PFC control mode when the effective value of the current is less than a preset current threshold and the peak value of the voltage is greater than a preset voltage threshold.

[0075] For example, the preset current threshold can be denoted as Iacth.

[0076] In this embodiment, the controller 71 performs real-time assessment of the load status and grid conditions of the air conditioner 10 based on the effective current value Iac and voltage peak value Vacpeak on the AC input side, and dynamically switches the PFC control mode accordingly.

[0077] Specifically, when the effective value of the detected current Iac is less than the preset current threshold, i.e., Iac < Iacth, and at the same time the peak value of the voltage Vacpeak is greater than the preset voltage threshold, i.e., Vacpeak > Vacpeakth, the controller 71 determines that the system is currently in a light-load operation state and the grid input voltage is relatively high. At this time, the rectified basic DC voltage is sufficient to support the normal operation of the subsequent inverter. If the second PFC control mode with a high bus voltage is continued to be maintained, the switching transistor Q1 in the PFC circuit 13 will frequently perform high-frequency operations, generating unnecessary switching losses and reducing the overall energy efficiency. Therefore, the controller 71 actively switches the air conditioner 10 from the second PFC control mode to the first PFC control mode. In the first PFC control mode, the target bus voltage is set to a relatively low level, thereby reducing the conduction loss and switching loss of the switching transistor Q1, and significantly improving the operation efficiency of the system under the light-load and high-input-voltage conditions on the premise of ensuring the basic power quality, and achieving energy-saving optimization.

[0078] In an embodiment of the present invention, when switching the air conditioner 10 from the current PFC control mode to the target PFC control mode according to the effective value of the current and the peak value of the voltage, the controller 71 is further configured to: when the effective value of the current is greater than or equal to the preset current threshold, and / or the peak value of the voltage is less than or equal to the preset voltage threshold, switch the air conditioner 10 from the current PFC control mode to the second PFC control mode.

[0079] In this embodiment, the controller 71 dynamically determines whether the air conditioner 10 needs to switch to a higher-performance PFC control mode based on real-time monitoring of the effective value of the AC input current Iac and the peak voltage Vacpeak. Specifically, when at least one of the following conditions is met: the effective value of the current Iac is greater than or equal to the preset current threshold Iacth (i.e., Iac≥Iacth), it indicates that the system load is heavy and the compressor power demand is high; the peak voltage Vacpeak is less than or equal to the preset voltage threshold Vacpeakth (i.e., Vacpeak≤Vacpeakth), it indicates that the grid input voltage is low and the base bus level after rectification is insufficient; the controller 71 then determines that the current operating condition has exceeded the applicable range of the first PFC control mode. In this case, if the target bus voltage continues to be maintained at a low level, it may lead to insufficient input voltage of the downstream inverter, causing compressor drive instability, aggravated current distortion, and even triggering undervoltage protection. Therefore, the controller 71 actively switches the air conditioner 10 from the first PFC control mode to the second PFC control mode. In the second PFC control mode, the target bus voltage is boosted to a higher level to ensure that the DC bus has sufficient energy reserves and stability, thereby guaranteeing that the inverter can reliably drive the compressor and maintain power quality with high power factor and low harmonic distortion. This switching strategy effectively balances the performance requirements and operational reliability of the system under harsh conditions such as heavy load and low voltage.

[0080] In one embodiment of the present invention, when determining the target coefficient corresponding to the target PFC control mode based on the effective value of the current, the controller 71 is configured to: when the air conditioner 10 switches from the current PFC control mode to the first PFC control mode, query a first preset lookup table based on the effective value of the current to determine the first target coefficient, wherein the first preset lookup table includes multiple sets of correspondences between the effective values ​​of the current and the first target coefficient, and the first target coefficient increases as the effective value of the current increases.

[0081] For example, the first target coefficient is denoted as K1, and the value range of the first bus coefficient K1 is [0.7, 1.0].

[0082] In this embodiment, when the air conditioner 10 switches from the second PFC control mode to the first PFC control mode, the controller 71 determines the target coefficient corresponding to this mode based on the real-time acquired effective current value Iac. Specifically, the controller 71 has a first preset lookup table pre-stored, which stores multiple sets of correspondences between effective current values ​​and the first target coefficient. As the effective current value increases, the first target coefficient K1 also increases accordingly, which can meet the actual operating requirements. For example, under light load conditions (i.e., the current is small), a lower target bus voltage can be used to reduce switching losses; while as the load gradually increases (i.e., the effective current value rises), in order to maintain the stable power supply capability of the downstream inverter, the target bus voltage value needs to be appropriately increased, so the corresponding target coefficient also increases. Through the lookup table method, the controller 71 can quickly and accurately obtain the appropriate first target coefficient K1 based on the current effective current value, and calculate a reasonable target bus voltage value in combination with the voltage peak value, thereby achieving a dynamic balance between efficiency and performance in the first PFC control mode.

[0083] In one embodiment of the present invention, when determining the target coefficient corresponding to the target PFC control mode based on the effective value of the current, the controller 71 is further configured to: when the air conditioner 10 switches from the current PFC control mode to the second PFC control mode, query a second preset lookup table based on the effective value of the current to determine the second target coefficient, wherein the second preset lookup table includes multiple sets of correspondences between the effective values ​​of the current and the second target coefficient, the second target coefficient increases as the effective value of the current increases, and the second target coefficient is greater than the first target coefficient.

[0084] For example, the second target coefficient is denoted as K2, and the range of the second target coefficient K2 is [1.0, 1.3].

[0085] When the first target coefficient K1 or the second target coefficient K2 increases with the increase of the effective value of the current Iac, the relationship between the two can be in the following form: it increases linearly or curvilinearly with the increase of the input current, or it increases linearly or curvilinearly on the basis of a plateau (i.e., piecewise constant).

[0086] In this embodiment, when the air conditioner 10 switches from the first PFC control mode to the second PFC control mode, the controller 71 determines the target coefficient corresponding to the second PFC control mode based on the real-time detected effective current value Iac. Specifically, the controller 71 has a second preset lookup table pre-stored, which stores multiple sets of correspondences between effective current values ​​and second target coefficients. Generally, the second target coefficient K2 increases with the increase of the effective current value Iac. This means that a relatively low second target coefficient K2 is used when the load is light to avoid excessively high bus voltage, while the second target coefficient K2 is gradually increased when the load increases to ensure that the DC bus has sufficient voltage margin to support the high power demands of the downstream inverter and compressor. Furthermore, all second target coefficients K2 in the second preset lookup table are set to be greater than the corresponding first target coefficient K1 in the first PFC control mode. That is, for the same or similar effective current values, the target bus voltage value in the second PFC control mode is always higher than the target bus voltage value in the first PFC control mode. This ensures that the system can maintain a higher bus voltage level under harsh operating conditions such as heavy load, high temperature, or low input voltage, thereby guaranteeing stable inverter operation, improving dynamic response capability, and achieving efficient power conversion close to unity power factor. At the same time, by looking up the second target coefficient K2, the controller 71 can accurately match the optimal target bus voltage value under different operating scenarios, maximizing overall energy efficiency while taking into account system reliability.

[0087] In one embodiment of the present invention, when generating a voltage control command based on the target bus voltage value and the actual bus voltage value, the controller 71 is configured to: determine the voltage deviation value between the target bus voltage value and the actual bus voltage value; and generate a voltage control command based on the voltage deviation value.

[0088] For example, the actual bus voltage value is denoted as Vdc, and the voltage deviation value is denoted as ΔV.

[0089] In this embodiment, when the controller 71 needs to generate a voltage control command for adjusting the PFC circuit, it first acquires the actual bus voltage value Vdc fed back by the voltage detection unit and the target bus voltage value calculated based on the current operating conditions in real time. Then, the controller 71 calculates the voltage deviation value ΔV between the two, i.e., ΔV = Vbus_target - Vdc. This voltage deviation value ΔV reflects the degree of deviation between the current DC bus voltage value and the desired set value. Based on this, the controller 71 performs calculations using a built-in closed-loop control algorithm (e.g., proportional-integral or proportional-integral-derivative control algorithm) based on the voltage deviation value ΔV. Finally, the controller 71 outputs a voltage control command, which directly represents the energy transfer intensity required to reduce the deviation, i.e., the amount of voltage regulation applied to the PFC circuit to achieve the target bus voltage value. This command will then be converted into a PWM signal to drive the switching transistor Q1 in the PFC circuit 13. This allows for continuous and dynamic correction of the actual bus voltage value Vdc, ensuring that it stably tracks the target bus voltage value Vbus_target, thereby providing a reliable and high-quality DC power supply for the downstream inverter.

[0090] In one embodiment of the present invention, when the air conditioner 10 is switched from the current PFC control mode to the target PFC control mode, the controller 71 is configured to: control the target bus voltage value corresponding to the current PFC control mode, and smoothly transition to the target bus voltage value corresponding to the target PFC control mode according to a preset ramp rate.

[0091] In this embodiment, when the controller 71 determines that the air conditioner 10 needs to be switched from the current PFC control mode to the target PFC control mode, it does not immediately jump the target bus voltage value, but adopts a smooth transition strategy to avoid system impact. Specifically, the controller 71 obtains the target bus voltage value corresponding to the current PFC control mode (e.g., denoted as Vbus_target1) and the target bus voltage value corresponding to the target PFC control mode (e.g., denoted as Vbus_target2). For example, if the current PFC control mode is the first PFC control mode and the target PFC control mode is the second PFC control mode, the controller 71 obtains the target bus voltage values ​​corresponding to the first PFC control mode and the second PFC control mode respectively, and controls the target bus voltage value Vbus_target1 to gradually and continuously transition to the target bus voltage value Vbus_target2 according to a preset ramp rate, thereby achieving a smooth switch. The preset ramp rate can be pre-set based on factors such as the system's dynamic response capability, inductor current change rate, and bus capacitor capacity. This ensures that the inductor current in the PFC circuit 13 does not change abruptly during the transition process, and that the stress on the switching transistor Q1 remains within a safe range. It also prevents overvoltage, undervoltage protection, or abnormal operation of the downstream inverter caused by sudden rises or falls in bus voltage. This not only effectively suppresses voltage oscillations, current spikes, and electromagnetic interference that may occur during mode switching, but also significantly improves the stability and reliability of system operation. The PFC control mode switching process is completed imperceptibly to the user, balancing energy efficiency optimization and dynamic performance.

[0092] According to the embodiment of the present invention, the air conditioner 10 can determine the target coefficient based on the effective value of the current and the peak value of the voltage of the AC input voltage, the condensing temperature and the compressor operating frequency. Alternatively, the target coefficient can be determined based on the effective value of the current, the peak value of the voltage, the condensing temperature and the compressor operating frequency. This allows the air conditioner to flexibly select the balance point between control accuracy and response speed according to the actual operating state. The target bus voltage value is then calculated based on the product of the determined target coefficient and the peak voltage. The voltage control command generated based on the target bus voltage value and the actual bus voltage value is transmitted to the PFC circuit to adjust the on / off state of the internal switching transistors of the PFC circuit. This allows the actual bus voltage value to quickly and smoothly approach and stabilize at the target bus voltage value. This ensures the reliable operation of the downstream inverter and compressor while achieving synergistic optimization of high power factor, low harmonic distortion, and high energy efficiency. It overcomes the problem that traditional methods are only applicable to DC-DC conversion scenarios and cannot be directly applied to systems such as air conditioners that require DC to AC conversion. By dynamically adjusting the target coefficient according to the operating conditions, it avoids the problem of excessively high bus voltage caused by using a fixed bus voltage under light load or high input voltage conditions. This effectively suppresses unnecessary switching losses, reduces the overall power consumption of the system, and improves operating efficiency.

[0093] The following is for reference. Figures 5-7 This invention describes a control method for an air conditioner according to an embodiment of the present invention.

[0094] like Figure 5 As shown, the air conditioner control method of this embodiment includes at least steps S1-S4.

[0095] Step S1: Obtain the effective value of current, peak voltage, condensing temperature, compressor operating frequency, and actual bus voltage of the AC input voltage.

[0096] Step S2: Determine the target coefficient based on the effective value of the current and the peak value of the voltage, or determine the target coefficient based on the effective value of the current, the peak value of the voltage, the condensing temperature and the compressor operating frequency.

[0097] Step S3: Determine the target bus voltage value based on the product of the voltage peak value and the target coefficient.

[0098] Step S4: Generate a voltage control command based on the target bus voltage value and the actual bus voltage value, and output the voltage control command to the PFC circuit so that the PFC circuit can control the on / off state of its internal switching transistors based on the voltage control command, so that the actual bus voltage value reaches the target bus voltage value. The voltage control command is used to characterize the amount of voltage regulation applied to the PFC circuit required for the actual bus voltage value to reach the target bus voltage value.

[0099] In one embodiment of the present invention, when determining the target coefficient based on the effective value of the current and the peak value of the voltage, or based on the effective value of the current, the peak value of the voltage, the condensing temperature and the compressor operating frequency, the method includes: switching the air conditioner from the current PFC control mode to the target PFC control mode based on the effective value of the current and the peak value of the voltage, or switching the air conditioner from the current PFC control mode to the target PFC control mode based on the peak value of the voltage, the condensing temperature and the compressor operating frequency; and determining the target coefficient corresponding to the target PFC control mode based on the effective value of the current.

[0100] In one embodiment of the present invention, such as Figure 6 As shown, when switching the air conditioner from the current PFC control mode to the target PFC control mode based on the voltage peak, condensing temperature and compressor operating frequency, the following steps are taken: when the condensing temperature is less than the preset condensing temperature threshold, the compressor operating frequency is less than the preset compressor operating frequency threshold, and the voltage peak is greater than the preset voltage threshold, the air conditioner is switched from the current PFC control mode to the first PFC control mode.

[0101] In one embodiment of the present invention, such as Figure 6As shown, when switching the air conditioner from the current PFC control mode to the target PFC control mode based on the voltage peak, condensing temperature and compressor operating frequency, the method further includes: when the condensing temperature is greater than or equal to a preset condensing temperature threshold, and / or the compressor operating frequency is greater than or equal to a preset compressor operating frequency threshold, and / or the voltage peak is less than or equal to a preset voltage threshold, the air conditioner is switched from the current PFC control mode to the second PFC control mode.

[0102] In one embodiment of the present invention, such as Figure 7 As shown, when switching the air conditioner from the current PFC control mode to the target PFC control mode based on the effective value of the current and the peak value of the voltage, the method includes: when the effective value of the current is less than the preset current threshold and the peak value of the voltage is greater than the preset voltage threshold, the air conditioner is switched from the current PFC control mode to the first PFC control mode.

[0103] In one embodiment of the present invention, such as Figure 7 As shown, when switching the air conditioner from the current PFC control mode to the target PFC control mode based on the effective value of the current and the peak value of the voltage, the method further includes: when the effective value of the current is greater than or equal to a preset current threshold, and / or the peak value of the voltage is less than or equal to a preset voltage threshold, switching the air conditioner from the current PFC control mode to the second PFC control mode.

[0104] In one embodiment of the present invention, reference is made to... Figure 6 and Figure 7 As shown, when determining the target coefficient corresponding to the target PFC control mode based on the effective value of the current, the process includes: when the air conditioner switches from the current PFC control mode to the first PFC control mode, querying a first preset lookup table based on the effective value of the current to determine the first target coefficient. The first preset lookup table includes multiple sets of correspondences between the effective values ​​of the current and the first target coefficient, and the first target coefficient increases as the effective value of the current increases.

[0105] In one embodiment of the present invention, reference is made to... Figure 6 and Figure 7 As shown, when determining the target coefficient corresponding to the target PFC control mode based on the effective value of the current, the process includes: when the air conditioner switches from the current PFC control mode to the second PFC control mode, querying a second preset lookup table based on the effective value of the current to determine the second target coefficient. The second preset lookup table includes multiple sets of correspondences between the effective values ​​of the current and the second target coefficient. The second target coefficient increases with the increase of the effective value of the current, and the second target coefficient is greater than the first target coefficient.

[0106] In one embodiment of the present invention, when generating a voltage control command based on a target bus voltage value and an actual bus voltage value, the method includes: determining a voltage deviation value between the target bus voltage value and the actual bus voltage value; and generating a voltage control command based on the voltage deviation value.

[0107] In one embodiment of the present invention, when switching the air conditioner from the current PFC control mode to the target PFC control mode, the method includes: controlling the target bus voltage value corresponding to the current PFC control mode, and smoothly transitioning to the target bus voltage value corresponding to the target PFC control mode according to a preset ramp rate.

[0108] According to the control method of the air conditioner of the present invention, by acquiring the effective value of current, peak value of voltage, condensing temperature and compressor operating frequency of AC input voltage, a target coefficient can be determined based on the effective value of current and peak value of voltage, or the target coefficient can be determined based on the effective value of current, peak value of voltage, condensing temperature and compressor operating frequency. This allows the air conditioner to flexibly select the balance point between control accuracy and response speed according to the actual operating state. The target bus voltage value is then calculated based on the product of the determined target coefficient and the peak voltage. The voltage control command generated based on the target bus voltage value and the actual bus voltage value is transmitted to the PFC circuit to adjust the on / off state of the internal switching transistors of the PFC circuit. This allows the actual bus voltage value to quickly and smoothly approach and stabilize at the target bus voltage value. This ensures the reliable operation of the downstream inverter and compressor while achieving synergistic optimization of high power factor, low harmonic distortion, and high energy efficiency. It overcomes the problem that traditional methods are only applicable to DC-DC conversion scenarios and cannot be directly applied to systems such as air conditioners that require DC to AC conversion. By dynamically adjusting the target coefficient according to the operating conditions, it avoids the problem of excessively high bus voltage caused by using a fixed bus voltage under light load or high input voltage conditions. This effectively suppresses unnecessary switching losses, reduces the overall power consumption of the system, and improves operating efficiency.

[0109] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0110] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An air conditioner, characterized in that, include: The refrigerant circulation loop allows the refrigerant to circulate in a cooling cycle through a circuit consisting of a compressor, condenser, electronic expansion valve, and evaporator. One of the condensers and the other of the evaporator is an outdoor heat exchanger, and the other is an indoor heat exchanger. A condensation temperature sensor is used to obtain the condensation temperature of the outdoor heat exchanger; The PFC circuit is used to correct the power factor of the AC input voltage and to regulate the actual bus voltage value by controlling the on / off state of its internal switching transistors. The controller is configured to: Obtain the effective value of the current, the peak value of the voltage, the condensing temperature, the compressor operating frequency, and the actual bus voltage value of the AC input voltage; The target coefficient is determined based on the effective value of the current and the peak value of the voltage, or the target coefficient is determined based on the effective value of the current, the peak value of the voltage, the condensing temperature and the compressor operating frequency; The target bus voltage value is determined by multiplying the peak voltage value and the target coefficient. A voltage control command is generated based on the target bus voltage value and the actual bus voltage value, and the voltage control command is output to the PFC circuit so that the PFC circuit controls the on / off state of its internal switching transistors based on the voltage control command, so that the actual bus voltage value reaches the target bus voltage value. The voltage control command is used to characterize the amount of voltage regulation applied to the PFC circuit required for the actual bus voltage value to reach the target bus voltage value.

2. The air conditioner according to claim 1, characterized in that, When determining a target coefficient based on the effective current value and the peak voltage value, or when determining a target coefficient based on the effective current value, the peak voltage value, the condensing temperature, and the compressor operating frequency, the controller is configured to: The air conditioner is switched from the current PFC control mode to the target PFC control mode based on the effective value of the current and the peak value of the voltage, or the air conditioner is switched from the current PFC control mode to the target PFC control mode based on the peak value of the voltage, the condensing temperature and the compressor operating frequency. The target coefficient corresponding to the target PFC control mode is determined based on the effective value of the current.

3. The air conditioner according to claim 2, characterized in that, When switching the air conditioner from the current PFC control mode to the target PFC control mode based on the voltage peak value, the condensing temperature, and the compressor operating frequency, the controller is configured to: When the condensing temperature is less than the preset condensing temperature threshold, the compressor operating frequency is less than the preset compressor operating frequency threshold, and the voltage peak value is greater than the preset voltage threshold, the air conditioner is switched from the current PFC control mode to the first PFC control mode.

4. The air conditioner according to claim 3, characterized in that, When switching the air conditioner from the current PFC control mode to the target PFC control mode based on the voltage peak value, the condensing temperature, and the compressor operating frequency, the controller is further configured to: When the condensing temperature is greater than or equal to the preset condensing temperature threshold, and / or the compressor operating frequency is greater than or equal to the preset compressor operating frequency threshold, and / or the voltage peak value is less than or equal to the preset voltage threshold, the air conditioner is switched from the current PFC control mode to the second PFC control mode.

5. The air conditioner according to claim 2, characterized in that, When switching the air conditioner from the current PFC control mode to the target PFC control mode based on the effective current value and the peak voltage value, the controller is configured to: When the effective value of the current is less than the preset current threshold and the peak value of the voltage is greater than the preset voltage threshold, the air conditioner is switched from the current PFC control mode to the first PFC control mode.

6. The air conditioner according to claim 5, characterized in that, When switching the air conditioner from the current PFC control mode to the target PFC control mode based on the effective value of the current and the peak value of the voltage, the controller is further configured to: When the effective value of the current is greater than or equal to the preset current threshold, and / or the peak voltage is less than or equal to the preset voltage threshold, the air conditioner is switched from the current PFC control mode to the second PFC control mode.

7. The air conditioner according to claim 3 or 5, characterized in that, When determining the target coefficient corresponding to the target PFC control mode based on the effective value of the current, the controller is configured to: When the air conditioner switches from the current PFC control mode to the first PFC control mode, it queries a first preset lookup table based on the effective value of the current to determine a first target coefficient. The first preset lookup table includes multiple sets of correspondences between effective current values ​​and the first target coefficient. The first target coefficient increases as the effective value of the current increases.

8. The air conditioner according to claim 4 or 6, characterized in that, When determining the target coefficient corresponding to the target PFC control mode based on the effective value of the current, the controller is further configured to: When the air conditioner switches from the current PFC control mode to the second PFC control mode, it queries a second preset lookup table based on the effective value of the current to determine the second target coefficient. The second preset lookup table includes multiple sets of correspondences between the effective values ​​of the current and the second target coefficient. The second target coefficient increases as the effective value of the current increases, and the second target coefficient is greater than the first target coefficient.

9. The air conditioner according to claim 1, characterized in that, When generating voltage control commands based on the target bus voltage value and the actual bus voltage value, the controller is configured to: Determine the voltage deviation between the target bus voltage value and the actual bus voltage value; The voltage control command is generated based on the voltage deviation value.

10. The air conditioner according to claim 2, characterized in that, When switching the air conditioner from the current PFC control mode to the target PFC control mode, the controller is configured to: Control the target bus voltage value corresponding to the current PFC control mode, and smoothly transition to the target bus voltage value corresponding to the target PFC control mode according to a preset ramp rate.

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