Air conditioner

Abstract

This application proposes an air conditioner in which the controller extracts a target electrical signal from the AC signal whose frequency is within a preset frequency range. The controller then adjusts the conduction parameters of the switching transistor based on the voltage magnitude of the target electrical signal. Since the voltage magnitude of the target electrical signal indicates the level of interference received by the PFC circuit from the AC signal, the controller can calculate the interference amplitude of the AC signal received by the PFC circuit, i.e., the magnitude of the influence of harmonic signals in the AC signal on the AC input voltage waveform. Therefore, when the interference received by the AC signal is significant, the controller reduces the conduction parameters of the switching transistor to dynamically adjust the conduction parameters and improve the overall operational stability of the unit.

Description

Technical Field

[0001] Some embodiments of this application relate to air conditioning technology. In particular, they relate to an air conditioner. Background Technology

[0002] With the improvement of industrial production and people's living standards, the widespread use of nonlinear electrical equipment generates more and more harmonics in AC power supplies. This not only increases the power supply loss of AC power and affects the normal operation of AC power protection devices, but also reduces the power factor of electrical equipment. Variable frequency air conditioners are a type of nonlinear electrical equipment. Therefore, in order to suppress the generation of harmonics and improve the power factor, power factor correction (PFC) technology has been introduced into variable frequency air conditioners.

[0003] Currently, PFC technology can be divided into passive power factor correction (PPFC) and active power factor correction (APFC). However, since passive power factor correction cannot meet the high energy efficiency requirements of air conditioners, active power factor correction has gradually become the mainstream solution in the air conditioner industry.

[0004] In active PFC control schemes, the controller mainly relies on the calculation of the effective value of the AC signal current when calculating the duty cycle of the switching transistor. However, the presence of harmonic signals in the AC signal will cause instability in the AC input voltage waveform. The unstable AC input voltage waveform will further affect the stability of the DC output of the PFC circuit, making it easier for the air conditioner to fail and shut down. Summary of the Invention

[0005] Some embodiments of this application provide an air conditioner that can improve the overall operational stability of the unit.

[0006] To achieve the above objectives, some embodiments of this application provide an air conditioner, including:

[0007] compressor;

[0008] Fan;

[0009] A power factor correction (PFC) circuit includes an AC input terminal, a rectifier circuit, a switching transistor, an inductor, a diode, and an output capacitor. The first terminal of the rectifier circuit is connected to the AC input terminal. The second terminal of the rectifier circuit is connected to the first terminal of the inductor. The second terminal of the inductor is connected to the first terminal of the switching transistor and the anode of the diode. The second terminal of the switching transistor is connected to ground. The cathode of the diode is connected to the first terminal of the output capacitor. The second terminal of the output capacitor is connected to ground. The first terminal of the output capacitor is also connected to the compressor and the fan. This circuit converts the AC power output from the AC input terminal into DC power and outputs the DC power to the compressor and the fan.

[0010] A controller, connected to the third terminal of the switching transistor, is used to control the switching transistor to be turned on or off.

[0011] The controller is configured as follows:

[0012] Obtain the AC signal at the AC input terminal;

[0013] The AC signal is filtered to obtain a target signal in the AC signal. The target signal is an AC signal whose frequency is within a preset frequency range. The voltage of the target signal is used to indicate the extent of interference from the PFC circuit to the AC signal.

[0014] The conduction parameters of the switching transistor are adjusted according to the voltage magnitude of the target electrical signal. The conduction parameters include the duty cycle and / or the conduction time. The voltage of the target electrical signal is inversely proportional to the value of the conduction parameters.

[0015] In the aforementioned air conditioner, the controller extracts a target electrical signal from the AC signal whose frequency falls within a preset frequency range. Based on the voltage magnitude of the target electrical signal, the controller adjusts the conduction parameters of the switching transistor. Since the voltage magnitude of the target electrical signal indicates the level of interference received by the PFC circuit from the AC signal, the controller can calculate the interference amplitude of the AC signal received by the PFC circuit by calculating the voltage of the target electrical signal. This means the controller determines the extent to which the AC input voltage waveform is affected by harmonic signals in the AC signal. Therefore, when the AC signal experiences significant interference, the controller reduces the conduction parameters of the switching transistor to ensure the highest power factor output. This dynamic adjustment of the switching transistor's conduction parameters improves the overall stability of the unit's operation.

[0016] In some embodiments of this application, the controller is configured as follows:

[0017] Obtain the voltage of the AC signal;

[0018] The correction coefficient is obtained based on the ratio of the voltage of the target electrical signal to the voltage of the AC electrical signal;

[0019] The conduction parameter is adjusted according to the magnitude of the correction coefficient, wherein the magnitude of the correction coefficient is inversely proportional to the value of the conduction parameter.

[0020] This configuration allows for compatibility with AC signals of different voltages, improving versatility.

[0021] In some embodiments of this application, the controller is configured as follows:

[0022] Obtain the current value of the AC signal;

[0023] Based on the preset correspondence between the current and the conduction parameter values, and the current value of the AC signal, the target value of the conduction parameter is obtained.

[0024] Based on the magnitude of the correction coefficient, the target value is adjusted, and the switching transistor is controlled to be turned on or off according to the adjusted target value.

[0025] This configuration reduces the adjustment range required by the controller when adjusting the conduction parameters of the switching transistor, thereby improving the operating efficiency of the PFC circuit.

[0026] In some embodiments of this application, when the correction coefficient is less than a first threshold, the switching transistor is controlled to be turned on or off according to the target value;

[0027] If the correction coefficient is greater than the first threshold, the target value is reduced, and the switching transistor is controlled to turn on or off according to the reduced target value.

[0028] This configuration reduces the controller's computational resources and improves the efficiency of adjusting conduction parameters.

[0029] In some embodiments of this application, the controller is configured as follows:

[0030] If the correction coefficient is greater than the second threshold, the switch is controlled to turn off, where the second threshold is greater than the first threshold.

[0031] This configuration allows the PFC circuit to stop outputting when the AC signal is subject to significant interference, thus improving the operational stability of the air conditioner.

[0032] In some embodiments of this application, the controller includes a processor and a voltage sampling circuit, one end of the voltage sampling circuit is connected to the AC input terminal, and the other end of the voltage sampling circuit is connected to the processor. The controller is configured to:

[0033] A voltage signal is obtained through the voltage sampling circuit, wherein the voltage signal is obtained by the voltage sampling circuit sampling the AC signal.

[0034] The processor takes the root mean square of the voltage signal to obtain the voltage of the AC signal.

[0035] This setting allows for accurate acquisition of the AC signal voltage at the AC input terminal, improving the operational stability of the air conditioner.

[0036] In some embodiments of this application, the controller includes a processor and a current sampling circuit, one end of the current sampling circuit is connected to the AC input terminal, and the other end of the current sampling circuit is connected to the processor. The controller is configured to:

[0037] The current signal is obtained through the current sampling circuit, and the current signal is obtained by the current sampling circuit sampling the voltage of the AC signal.

[0038] The processor takes the root mean square of the current signal to obtain the current value of the alternating current signal.

[0039] This setting allows for accurate acquisition of the current value of the AC signal at the AC input terminal, improving the operational stability of the air conditioner.

[0040] In some embodiments of this application, the controller is configured as follows:

[0041] After adjusting the conduction parameters of the switching transistor, the operating parameters of the target device are adjusted. The target device includes the compressor and the fan, and the operating parameters include the operating frequency and / or power.

[0042] This configuration allows for simultaneous regulation of the operating efficiency of the switching transistor and the air conditioner's load, thereby improving the air conditioner's operational stability.

[0043] In some embodiments of this application, the preset frequency range is determined based on the fundamental frequency corresponding to the AC signal.

[0044] By setting the above parameters, different preset frequency ranges can be set for different fundamental frequencies, which can ensure compatibility with different AC power supplies.

[0045] In some embodiments of this application, the preset frequency range includes a target frequency value, which is seven times the fundamental frequency.

[0046] This setup allows for a quantitative and specific representation of the impact of the PFC circuit on the AC power input voltage, enabling the controller to more precisely regulate the switching transistors. Attached Figure Description

[0047] To more clearly illustrate the implementation methods in some embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0048] Figure 1 This is a schematic diagram of the structure of a bridgeless PFC circuit according to some embodiments of this application;

[0049] Figure 2 The diagram shows the waveforms of the output voltages of AC power supply 1 and AC power supply 2 in some embodiments of this application.

[0050] Figure 3 The voltage waveforms of AC power supply 1 and AC power supply 2 in a single cycle are shown in some embodiments of this application.

[0051] Figure 4 This is a schematic diagram of the waveforms of the output voltages of AC power supply 1 and AC power supply 2 after Fast Fourier Transform (FFT) according to some embodiments of this application.

[0052] Figure 5 This is one of the schematic diagrams illustrating the execution flow of the controller in some embodiments of this application;

[0053] Figure 6 This is one of the structural schematic diagrams of the controller in some embodiments of this application;

[0054] Figure 7 This is a second schematic diagram of the controller structure according to some embodiments of this application;

[0055] Figure 8 The diagram shows the waveforms of the target electrical signals after taking the root mean square of AC power supply 1 and AC power supply 2 according to some embodiments of this application.

[0056] Figure 9 This is a second schematic diagram of the execution flow of the controller in some embodiments of this application;

[0057] Figure 10 This is the third schematic diagram of the controller structure in some embodiments of this application. Detailed Implementation

[0058] To make the objectives, implementation methods and advantages of this application clearer, the exemplary implementation methods of this application will be clearly and completely described below with reference to the accompanying drawings of the exemplary embodiments of this application. Obviously, the described exemplary embodiments are only some embodiments of this application, and not all embodiments.

[0059] It should be noted that the brief descriptions of terms in this application are only for the convenience of understanding the embodiments described below, and are not intended to limit the embodiments of this application. Unless otherwise stated, these terms should be understood in their ordinary and common meaning.

[0060] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover but not exclusively include, for example, a product or device that includes a series of components is not necessarily limited to those that are explicitly listed, but may include other components that are not explicitly listed or that are inherent to such product or device.

[0061] In the description of this application, 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 application 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 application.

[0062] 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. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0063] In the description of this application, it should be noted that, unless otherwise expressly 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 between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0064] This application provides an air conditioner that includes a compressor, an indoor fan, an outdoor fan, a condenser, an expansion valve, and an evaporator to perform a refrigeration cycle. The air conditioner can be an inverter air conditioner, an inverter portable air conditioner, an inverter window air conditioner, or an inverter dehumidifier, etc.

[0065] The air conditioner includes a casing and a power management module installed inside the casing. The input terminal of the power management module is connected to an AC power source, and the output terminal of the power management module is connected to various air conditioning components inside the casing. It is used to convert the AC power output from the AC power source into DC power to provide power to various loads of the air conditioner, thereby enabling the air conditioner to operate normally. The loads include the compressor, indoor fan, and outdoor fan.

[0066] The power management module contains a circuit board on which several components are connected.

[0067] The power management module includes a PFC circuit and a controller 102, such as Figure 1 As shown, the input terminal of the PFC circuit is connected to the AC input terminal, and the output terminal of the PFC circuit is connected to the controller 102.

[0068] In some embodiments, the PFC circuit may include an AC input terminal, a rectifier circuit 101, a switching transistor, an inductor, a diode, and an output capacitor, such as Figure 1 As shown, the input terminal of the rectifier circuit 101 is connected to the AC input terminal, the output terminal of the rectifier circuit 101 is connected to the first terminal of the inductor, the second terminal of the inductor is connected to the input terminal of the switching transistor and the positive terminal of the diode, the output terminal of the switching transistor is connected to the input terminal of the rectifier circuit 101 and the ground terminal, the negative terminal of the diode is connected to the first terminal of the output capacitor, the second terminal of the output capacitor is connected to the load of the air conditioner and the ground terminal, and the first terminal of the output capacitor is also connected to the load of the air conditioner.

[0069] The AC input terminal is connected to the AC power supply. When the AC power supply and the power management module are connected, the AC input terminal is connected to the output terminal of the AC power supply, thereby outputting AC power to the PFC circuit through the AC input terminal.

[0070] In some embodiments, the AC input terminal may include a first input terminal and a second input terminal, which are respectively connected to multiple output terminals of the AC power supply. The first input terminal and the second input terminal have different polarities. For example, the first input terminal may be a live wire connection terminal, which is connected to the live wire terminal of the AC power supply, and the second input terminal may be a neutral wire connection terminal, which is connected to the neutral wire terminal of the AC power supply.

[0071] In some embodiments, such as Figure 1 As shown, the rectifier circuit 101 may include a rectifier bridge, which includes a first rectifier diode D1, a second rectifier diode D2, a third rectifier diode D3, and a fourth rectifier diode D4. The positive terminal of the first rectifier diode D1 is connected to the first input terminal, the positive terminal of the second rectifier diode D2 is connected to the second input terminal, the negative terminals of the first rectifier diode D1 and the second rectifier diode D2 are both connected to the first terminal of the inductor, the positive terminal of the third rectifier diode D3 is connected to the positive terminal of the fourth rectifier diode D4, the negative terminal of the third rectifier diode D3 is connected to the positive terminal of the first rectifier diode D1, and the negative terminal of the fourth rectifier diode D4 is connected to the positive terminal of the second rectifier diode D2.

[0072] When the switching transistor Q is off, the circuit operates in passive PFC mode. The AC input voltage is converted to DC voltage by the rectifier circuit 101. When the voltage of the output capacitor C is lower than the output voltage of the rectifier circuit 101, the diode D will conduct, charging the output capacitor C. However, since the situation where the output voltage of the rectifier circuit 101 is higher than the voltage across the output capacitor C cannot cover the entire power supply sinusoidal cycle, the conduction time of the diode D is short, and the charging time of the output capacitor C is also short, resulting in a low power factor.

[0073] When the PFC circuit performs single-pulse control, the controller 102 outputs a pulse width modulation (PWM) signal with a certain duty cycle to the switch Q, so that the switch Q is in both on and off states within one cycle.

[0074] When the switching transistor Q is turned on, the input voltage is sinusoidal, so there is a zero point in the input voltage. When the zero-crossing of the AC input voltage is detected, the controller 102 outputs a PWM signal including the PFC duty cycle to the switching transistor Q. When the switching transistor Q is turned on, the AC input voltage charges the inductor. When the switching transistor Q is turned off, the AC voltage and the inductor together charge the output capacitor C. Therefore, in each power cycle, the diode D conducts for a longer time, allowing for a longer charging time for the output capacitor C, resulting in a higher power factor.

[0075] However, in actual use, the switching transistor Q will introduce significant harmonics to the AC power supply voltage when it is turned on, and the harmonics will be even more severe if the AC power supply itself is not stable enough.

[0076] Since the switching on and off of a single-pulse PFC depends entirely on the zero-crossing point of the AC power input voltage, the greater the deviation of the harmonics from the standard sine wave, the greater the impact on the accuracy of the zero-crossing detection. Increased zero-crossing detection error increases the probability of PFC circuit overcurrent shutdown failure.

[0077] like Figure 2 As shown, under two different power supply conditions, AC power supply one and AC power supply two, the same PFC output duty cycle will result in different harmonic magnitudes for the input voltage. The horizontal axis in the figure represents time (s) and the vertical axis represents voltage (V).

[0078] To clearly illustrate the impact of the switching transistor on input voltage distortion, Figure 2 The waveforms of the input voltages of the two AC power supplies are amplified by taking a complete power supply cycle and compared with the standard sinusoidal voltage, as shown in Figure 3.

[0079] As can be seen from the comparison, under different power supply conditions, even with the same PFC output duty cycle, the distortion of the input voltage caused by the PFC circuit varies greatly. When the switching transistor is turned on (about 0.001 to 0.003s), it causes severe distortion to the AC input voltage, which is very different from the ideal sinusoidal AC power supply voltage waveform.

[0080] If the conduction of the switching transistor introduces more high-frequency harmonics into the AC power supply, the conditions of the AC signal output by the AC power supply will be more severe than those of the previous AC power supply. Figure 2The AC power supply shown is even worse, producing an AC input voltage that deviates further from the standard sine wave. However, the control of the switching transistor requires calculating the zero-crossing point of the AC input voltage based on the sampled AC input voltage as the turn-on time of the single-pulse PWM. Severely distorted input voltage will affect the accuracy of zero-crossing detection. Once a false zero-crossing is detected, it will cause the switching transistor to not turn on or to turn on at the wrong time. False zero-crossing will cause the PFC circuit to malfunction and shut down, affecting the overall stability of the machine.

[0081] Based on the above issues, in order to specifically demonstrate the impact of the switching transistor's on / off state on the AC power supply input voltage, simulations were performed on AC input signals under different power supply conditions. It was found that during the simulation of AC power supply one and AC power supply two, both with a fundamental frequency of 60Hz, the controller 102 acquires the AC signal output from the AC input terminal. This AC signal includes harmonic components from the AC power supply input signal. After performing a Fast Fourier Transform (FFT) on the sampled AC signal, the harmonic components at various frequency bands caused by the switching transistor's on / off state can be obtained. The input voltage waveforms of AC power supply one and AC power supply two after FFT calculation are shown below. Figure 4 As shown.

[0082] from Figure 4 As can be seen, at the same fundamental frequency, the high-frequency harmonic components caused by the conduction of the switching transistor are mainly in the 3rd, 5th, 7th, 9th... harmonics. Therefore, by detecting the voltage amplitude of these harmonics, the extent of interference from the PFC circuit to the AC power supply can be reflected. If the voltage amplitude of a certain harmonic is larger, it means that the AC power supply is more affected by the PFC circuit. Here, the i-th harmonic refers to a signal with a frequency i times that of the fundamental frequency.

[0083] Based on the above, this application provides an air conditioner that extracts a target electrical signal from the AC signal whose frequency is within a preset frequency range. The controller adjusts the conduction parameters of the switching transistor based on the voltage magnitude of the target electrical signal. Since the voltage magnitude of the target electrical signal indicates the level of interference received by the PFC circuit from the AC signal, the controller 102 can calculate the interference amplitude of the AC signal received by the PFC circuit by calculating the voltage of the target electrical signal. This means the magnitude of the influence of harmonic signals in the AC signal on the AC input voltage waveform. Therefore, when the AC signal experiences significant interference, the controller reduces the conduction parameters of the switching transistor to ensure the highest power factor output. This dynamic adjustment of the switching transistor's conduction parameters improves the overall stability of the unit's operation.

[0084] In some embodiments, the above process can be implemented by control methods, such as... Figure 5 As shown, this control method is applied to Figure 1 The controller 102 shown herein may include the following steps:

[0085] Step S101: Obtain the AC signal output from the AC input terminal;

[0086] Step S102: Filter the AC signal to obtain the target signal in the AC signal. The target signal is the signal in the AC signal whose frequency is within a preset frequency range. The voltage of the target signal is used to indicate the extent of interference from the PFC circuit to the AC signal.

[0087] Step S103: Adjust the conduction parameters of the switching transistor according to the voltage magnitude of the target electrical signal. The conduction parameters include the duty cycle and / or the conduction time. The voltage of the target electrical signal is inversely proportional to the value of the conduction parameters.

[0088] It should be understood that the main influence of the PFC circuit on the AC input signal lies in the high-frequency harmonic components. These high-frequency harmonic components can be obtained by filtering the AC signal output from the AC input terminal. Therefore, after filtering the AC signal, high-frequency harmonic signals, such as the 3rd, 5th, 7th, 9th... harmonic signals, can be obtained. The conduction parameters of the switching transistor can then be adjusted according to the voltage magnitude of the high-frequency harmonic signals. The higher the voltage of the high-frequency harmonic signals, the greater the influence of the PFC circuit on the AC input voltage.

[0089] In some embodiments, such as Figure 6 As shown, the controller 102 may include a processor and a bandpass filter. When the controller 102 performs filtering processing on the AC signal, it can be implemented by the controller 102 through the bandpass filter. That is, after the AC signal is input to the controller 102 through the input terminal, it first passes through the bandpass filter in the controller 102. After the bandpass filter performs filtering processing on the AC signal, the controller 102 adjusts the conduction parameters of the switching transistor based on the voltage magnitude of the filtered target signal.

[0090] Since bandpass filters need to directly filter AC signals, it is necessary to select bandpass filters with large upper and lower bandwidth frequencies, such as Sallen-Key bandpass filters or bandpass filter inverting attenuator circuits.

[0091] In some embodiments, such as Figure 6 As shown, the controller 102 may include a voltage sampling circuit. The input terminal of the voltage sampling circuit is connected to the AC input terminal to obtain the AC signal output by the AC input terminal. Then, the controller 102 obtains the corresponding voltage value based on the sampled AC signal.

[0092] Since the voltage sampling circuit directly samples the AC signal, the sampling terminal of the voltage sampling circuit needs to meet the requirements of a high-voltage environment, such as differential operational amplifiers and analog-to-digital converters.

[0093] It is understandable that since the AC input terminal includes a first input terminal and a second input terminal, the voltage sampling circuit also includes a first input terminal and a second input terminal. The first input terminal of the AC input terminal is connected to the first input terminal of the voltage sampling circuit, and the second input terminal of the AC input terminal is connected to the second input terminal of the voltage sampling circuit. Thus, the voltage sampling circuit obtains a sinusoidal AC signal through the first input terminal and the second input terminal and samples its voltage.

[0094] Since the output AC signal will be different at different fundamental frequencies, in order to achieve compatibility with different AC power supplies, the preset frequency range can be determined based on the fundamental frequency of the AC signal. That is, after the controller 102 receives the AC signal, it obtains the fundamental frequency of the AC signal and then determines the preset frequency range based on the fundamental frequency.

[0095] It is understandable that when the air conditioner is connected to an AC power source with a certain fundamental frequency, a fixed preset frequency range can be set in advance, thereby saving the controller 102 from the calculation process of calculating the preset frequency range based on the fundamental frequency and reducing the consumption of computing resources.

[0096] By setting the above parameters, different preset frequency ranges can be set for different fundamental frequencies, which can ensure compatibility with different AC power supplies.

[0097] In some embodiments, the preset frequency range includes a target frequency value, which is three, five, or seven times the fundamental frequency.

[0098] For example, if the target frequency is 7 times the fundamental frequency, then the middle frequency of the preset frequency range is 7 times the fundamental frequency, and the bandwidth is 200Hz.

[0099] This configuration allows for a quantitative and specific representation of the impact of the PFC circuit on the AC power input voltage, enabling the controller 102 to more accurately regulate the switching transistor.

[0100] Preferably, from Figure 4 It can be seen that the peak value of the 7th harmonic is greater than that of other high-frequency harmonics. Therefore, selecting the seventh fundamental frequency as the target frequency value can make the voltage of the target electrical signal larger than that when other high-frequency harmonics are selected. This allows for a clearer determination of the interference of the switching transistor on the input electrical signal of the AC power supply.

[0101] In some embodiments, when the controller 102 adjusts the conduction parameter based on the voltage magnitude of the target electrical signal, it can obtain the value through a pre-set correspondence between the voltage of the target electrical signal and the value of the conduction parameter. That is, after obtaining the voltage value of the target electrical signal, the controller 102 finds the corresponding value of the conduction parameter by looking up the correspondence, and then switches the transistor on or off according to the target value of the conduction parameter.

[0102] Because the voltage value of the AC signal output by the AC power supply is variable, in order to be compatible with AC signals of different voltages, the controller 102 can control the switching transistor to be turned on or off based on the proportion of the target signal in the AC signal. Therefore, when the target signal accounts for a large proportion of the AC signal, a smaller value of the on-state parameter is used, and when the target signal accounts for a small proportion of the AC signal, a larger value of the on-state parameter is used.

[0103] In some embodiments, the controller 102 is configured to:

[0104] Obtain the voltage of the alternating current signal;

[0105] The correction coefficient is obtained based on the ratio of the voltage of the target electrical signal to the voltage of the AC electrical signal.

[0106] Adjust the conduction parameters according to the magnitude of the correction coefficient. The magnitude of the correction coefficient is inversely proportional to the value of the conduction parameters.

[0107] It should be understood that when the controller 102 obtains the voltage of the AC signal, the voltage sampling circuit needs to directly detect the voltage of the AC signal at the input terminal of the inductor to obtain the voltage value of the AC signal, and then the processor obtains the voltage of the AC signal.

[0108] That is, the controller 102 includes a bandpass filter, a voltage sampling circuit, and a processor, such as... Figure 7 As shown, the first end of the bandpass filter is connected to the AC input terminal, the second end of the bandpass filter is connected to the first input terminal of the voltage sampling circuit, the second input terminal of the voltage sampling circuit is connected to the AC input terminal, and the output terminal of the voltage sampling circuit is connected to the processor. Thus, the voltage sampling circuit can obtain the filtered target electrical signal through the first input terminal and obtain the AC electrical signal through the second input terminal, and then output the voltage values ​​of the target electrical signal and the AC electrical signal to the processor through the output terminal.

[0109] It is understandable that since the AC input terminal includes a first input terminal and a second input terminal, the bandpass filter also includes a first input terminal and a second input terminal. The first input terminal of the AC input terminal is connected to the first input terminal of the bandpass filter, and the second input terminal of the AC input terminal is connected to the second input terminal of the bandpass filter. Thus, the bandpass filter obtains a sinusoidal AC signal through the first input terminal and the second input terminal and filters it.

[0110] In some embodiments, the voltage sampling circuit may include a first voltage sampling unit and a second voltage sampling unit. The first sampling unit samples the voltage of the target electrical signal and outputs the voltage value of the target electrical signal to the processor. The second voltage sampling unit samples the voltage of the AC signal and outputs the voltage value of the AC signal to the processor.

[0111] In some embodiments, the voltage sampling unit and voltage sampling circuit can employ conventional voltage sampling methods, such as analog-to-digital converters. The specific configuration can be determined by those skilled in the art based on the actual situation, and this application does not impose any limitations.

[0112] For example, the process of calculating the correction factor may include:

[0113] 1. Sample the AC signal Vac at the input terminal of the inductor and calculate the effective voltage value Vac_rms;

[0114] 2. After bandpass filtering, high-frequency harmonics in the AC voltage are extracted, such as the 3rd, 5th, or 7th harmonics;

[0115] 3. Calculate the effective voltage value Vac_bsp_rms of the high-frequency harmonics;

[0116] 4. Calculate the proportion of high-frequency harmonics in the AC signal, and use it as the correction coefficient k = Vac_bsp_rms / Vac_rms.

[0117] After calculating the correction coefficient k, the duty cycle and conduction time of the switching transistor can be updated according to the correction coefficient k. Since the correction coefficient k characterizes the influence of the switching transistor's on / off state on the input electrical signal, updating the duty cycle and conduction time of the switching transistor according to the correction coefficient k can compensate for the influence of the switching transistor's on / off state on the input electrical signal.

[0118] For example, targeting Figure 2 After filtering AC power supply one and AC power supply two for the 7th harmonic, a 7th harmonic signal is obtained. The effective voltage values ​​obtained by taking the root mean square of the 7th harmonic signal are close to 3V and 7V, respectively. Figure 8As shown, the PFC duty cycle correction factors at this time are 3V / 115V = 2.6% and 7V / 115V = 6.1%, respectively. The two correction factors differ by more than 2 times. However, for AC power supplies that are closer to ideal conditions, the correction factor k is close to 0. Therefore, the correction factor k is sufficient to identify the quality of the AC power supply and to represent the impact of single-pulse PFC on the AC power supply voltage.

[0119] Understandably, it is compatible with AC signals of different voltages, thus improving versatility.

[0120] In some embodiments, when the correction coefficient is less than a first threshold, the switching transistor is controlled to turn on or off according to the target value;

[0121] And / or, if the correction coefficient is greater than or equal to the first threshold, the target value is reduced, and the switching transistor is controlled to turn on or off according to the reduced target value.

[0122] It should be understood that when the correction coefficient is less than the first threshold, it means that the conduction of the switch has little interference with the input voltage. In this case, the switch can be turned on and off according to the target value of the conduction parameters. However, when the correction coefficient is greater than or equal to the first threshold, the conduction of the switch has a greater interference with the input voltage. It is necessary to adjust the conduction parameters of the switch so that the waveform of the electrical signal output to the load can be consistent with the waveform of the standard electrical signal.

[0123] The specific value of the first threshold can be set by those skilled in the art according to the actual situation, and this application embodiment does not impose any restrictions.

[0124] This configuration reduces the computational resources of the controller 102 and improves the efficiency of adjusting the conduction parameters.

[0125] In some embodiments, controller 102 is configured to:

[0126] If the correction coefficient is greater than the second threshold, the control switch is turned off, and the second threshold is greater than the first threshold.

[0127] It should be understood that when the correction coefficient is greater than the second threshold, it indicates that the interference of the switching transistor on the input voltage has reached a serious level. At this time, normal switching of the transistor will aggravate the impact on the input AC signal. Therefore, it is necessary to control the switching transistor to turn off, so as to convert the input AC signal into an AC signal according to the working mode of the passive PFC circuit and output it to the load of the air conditioner, thereby realizing the power supply of the air conditioner.

[0128] The specific value of the second threshold can be set by those skilled in the art according to the actual situation, and this application embodiment does not impose any restrictions.

[0129] This configuration allows the switching transistor to disconnect when the AC signal is subject to significant interference, thereby improving the operational stability of the air conditioner.

[0130] In some embodiments, controller 102 is configured to:

[0131] After adjusting the conduction parameters of the switching transistor, adjust the operating parameters of the target devices, including compressors and fans, including operating frequency and / or power.

[0132] It should be understood that, in order to ensure that the load of the air conditioner is not affected by harmonic signals, after the controller 102 adjusts the conduction parameters of the switching transistor, the operating parameters of the compressor and fan can be further adjusted. For example, the operating frequency and power of the compressor and fan can be reduced, thereby further limiting the operation of the air conditioner to ensure the stability of the air conditioner's operation.

[0133] For example, if the air conditioner determines that the correction coefficient is too small based on the ratio between the voltage value of the target electrical signal and the voltage value of the AC signal, that is, the conduction of the switching transistor does not have a significant impact on the input AC signal, the air conditioner will still execute the switching transistor on and off with the conduction parameters of the target value, and the operating parameters of the compressor and fan will still operate at the standard values, thereby maintaining the normal operation of the air conditioner.

[0134] If the air conditioner determines that the correction coefficient is too large based on the ratio between the voltage value of the target electrical signal and the voltage value of the AC signal, meaning that the conduction of the switching transistor has had an excessive impact on the input AC signal, and the air conditioner continues to use the target conduction parameter to switch the transistor on and off, it will affect the normal operation of the air conditioner. Therefore, the air conditioner needs to reduce the value of the conduction parameter and reduce the operating parameters of the compressor and fan to limit the output of the bridgeless PFC circuit and reduce the impact on the normal operation of the air conditioner.

[0135] This configuration allows for simultaneous regulation of the operating efficiency of the switching transistor and the air conditioner's load, thereby improving the air conditioner's operational stability.

[0136] In some embodiments, since pulses exist in both the AC signal and the target signal, it is necessary to calculate the effective voltage value when calculating the voltage value of the AC signal. The effective voltage value can be, for example, the average value or the root mean square value. The same applies to the voltage value of the target signal.

[0137] Taking the root mean square (RMS) of the AC signal as the voltage value of the AC signal as an example, the processor performs RMS calculation on the AC signal to obtain the voltage value of the AC signal.

[0138] This setting allows for accurate acquisition of the AC signal voltage at the AC input terminal, improving the operational stability of the air conditioner.

[0139] In some embodiments, when adjusting the value of the conduction parameter, the controller 102 can first calculate the target value of the corresponding conduction parameter based on the current value of the AC signal, and then adjust the target value based on the voltage magnitude of the target signal or the magnitude of the correction coefficient.

[0140] For example, such as Figure 9 As shown, when adjusting the conduction parameters according to the voltage magnitude of the target electrical signal, the controller 102 can be configured to perform the following steps:

[0141] Step S104: Obtain the current value of the AC signal;

[0142] Step S105: Based on the preset correspondence between the current and the conduction parameter values, and the current value of the AC signal, obtain the target value of the conduction parameter.

[0143] Step S103: Adjust the target value according to the voltage magnitude of the target electrical signal, and control the switching transistor to turn on or off according to the adjusted target value.

[0144] For example, when adjusting the conduction parameters according to the magnitude of the correction coefficient, the controller 102 described above can be configured as follows:

[0145] Obtain the current value of the alternating current signal;

[0146] Based on the preset correspondence between the current and the conduction parameter values, and the current value of the AC signal, the target value of the conduction parameter is obtained.

[0147] Adjust the target value according to the magnitude of the correction coefficient, and control the switching transistor to turn on or off according to the adjusted target value.

[0148] This configuration reduces the adjustment range of the controller 102 when adjusting the conduction parameters of the switching transistor, thereby improving the working efficiency of the PFC circuit.

[0149] In some embodiments, the controller 102 obtains the current value of the AC signal through a current sampling circuit, such as... Figure 10 As shown, based on Figure 6 The controller 102 shown may further include a current sampling circuit, one end of which is connected to the AC input terminal, and the other end of which is connected to the processor. The controller 102 is configured to:

[0150] The current signal is obtained by sampling the AC signal through a current sampling circuit.

[0151] The processor takes the root mean square of the current signal to obtain the current value of the AC signal.

[0152] Since the current sampling circuit directly samples the AC signal, it needs to employ methods for AC current detection, such as current transformers. Current transformers can safely isolate AC signals. By passing the AC signal through the toroidal core of the transformer, the secondary coil of the transformer induces a current signal proportional to the primary current. This signal is usually a small current (e.g., 0-2mA), which the processor can then further sample and process.

[0153] It is understandable that since the AC input terminal includes a first input terminal and a second input terminal, the current sampling circuit also includes a first input terminal and a second input terminal. The first input terminal of the AC input terminal is connected to the first input terminal of the current sampling circuit, and the second input terminal of the AC input terminal is connected to the second input terminal of the current sampling circuit. Thus, the current sampling circuit obtains a sinusoidal AC signal through the first input terminal and the second input terminal and samples the current.

[0154] This setting allows for accurate acquisition of the current value of the AC signal at the AC input terminal, improving the operational stability of the air conditioner.

[0155] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0156] For ease of explanation, the above description has been provided in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed above. Various modifications and variations can be obtained based on the above teachings. The selection and description of the above embodiments are for the purpose of better explaining the principles and practical applications, thereby enabling those skilled in the art to better utilize the described embodiments and various different variations of embodiments suitable for specific use considerations.

Claims

1. An air conditioner, characterized in that, The air conditioner includes: compressor; Fan; A power factor correction (PFC) circuit includes an AC input terminal, a rectifier circuit, a switching transistor, an inductor, a diode, and an output capacitor. The first terminal of the rectifier circuit is connected to the AC input terminal. The second terminal of the rectifier circuit is connected to the first terminal of the inductor. The second terminal of the inductor is connected to the first terminal of the switching transistor and the anode of the diode. The second terminal of the switching transistor is connected to ground. The cathode of the diode is connected to the first terminal of the output capacitor. The second terminal of the output capacitor is connected to ground. The first terminal of the output capacitor is also connected to the compressor and the fan. This circuit converts the AC power output from the AC input terminal into DC power and outputs the DC power to the compressor and the fan. A controller, connected to the third terminal of the switching transistor, is used to control the switching transistor to be turned on or off. The controller is configured as follows: Obtain the AC signal output from the AC input terminal; The AC signal is filtered to obtain a target signal in the AC signal. The target signal is an AC signal whose frequency is within a preset frequency range. The voltage of the target signal is used to indicate the extent of interference from the PFC circuit to the AC signal. The conduction parameters of the switching transistor are adjusted according to the voltage magnitude of the target electrical signal. The conduction parameters include the duty cycle and / or the conduction time. The voltage of the target electrical signal is inversely proportional to the value of the conduction parameters.

2. The air conditioner as described in claim 1, characterized in that, The controller is configured to: Obtain the voltage of the AC signal; The correction coefficient is obtained based on the ratio of the voltage of the target electrical signal to the voltage of the AC electrical signal; The conduction parameter is adjusted according to the magnitude of the correction coefficient, wherein the magnitude of the correction coefficient is inversely proportional to the value of the conduction parameter.

3. The air conditioner as described in claim 2, characterized in that, The controller is configured to: Obtain the current value of the AC signal; Based on the preset correspondence between the current and the conduction parameter values, and the current value of the AC signal, the target value of the conduction parameter is obtained. Based on the magnitude of the correction coefficient, the target value is adjusted, and the switching transistor is controlled to be turned on or off according to the adjusted target value.

4. The air conditioner as described in claim 3, characterized in that, If the correction coefficient is less than the first threshold, the switching transistor is controlled to be turned on or off according to the target value; If the correction coefficient is greater than the first threshold, the target value is reduced, and the switching transistor is controlled to turn on or off according to the reduced target value.

5. The air conditioner as described in claim 4, characterized in that, The controller is configured to: If the correction coefficient is greater than the second threshold, the switch is controlled to turn off, where the second threshold is greater than the first threshold.

6. The air conditioner as described in claim 2, characterized in that, The controller includes a processor and a voltage sampling circuit. One end of the voltage sampling circuit is connected to the AC input terminal, and the other end of the voltage sampling circuit is connected to the processor. The controller is configured to: A voltage signal is obtained through the voltage sampling circuit, wherein the voltage signal is obtained by the voltage sampling circuit sampling the AC signal. The processor takes the root mean square of the voltage signal to obtain the voltage of the AC signal.

7. The air conditioner as described in claim 3, characterized in that, The controller includes a processor and a current sampling circuit. One end of the current sampling circuit is connected to the AC input terminal, and the other end of the current sampling circuit is connected to the processor. The controller is configured to: The current signal is obtained through the current sampling circuit, and the current signal is obtained by the current sampling circuit sampling the voltage of the AC signal. The processor takes the root mean square of the current signal to obtain the current value of the alternating current signal.

8. The air conditioner as described in claim 1, characterized in that, The controller is configured to: After adjusting the conduction parameters of the switching transistor, the operating parameters of the target device are adjusted. The target device includes the compressor and the fan, and the operating parameters include the operating frequency and / or power.

9. The air conditioner as described in claim 1, characterized in that, The preset frequency range is determined based on the fundamental frequency corresponding to the AC signal.

10. The air conditioner as described in claim 9, characterized in that, The preset frequency range includes a target frequency value, which is seven times the fundamental frequency.

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