Control method and device of variable frequency driving circuit, electric control box and air conditioner

Abstract

The application discloses a control method and device of a variable-frequency driving circuit, an electric control box and an air conditioner. According to a direct-current voltage signal output by a rectifier bridge, a ripple voltage signal in the direct-current voltage signal is acquired. According to the ripple voltage signal, a first amplitude of an n-th harmonic signal corresponding to the direct-current voltage signal is acquired. According to the first amplitude, a remaining service life of a smoothing processing unit is determined. According to the first amplitude and the remaining service life, a target operating power of a load corresponding to the variable-frequency driving circuit is determined, so that the load operates according to the target operating power. In the scheme, the service life of the smoothing processing unit is determined through the amplitude of the direct-current voltage signal, the influence on the smoothing processing unit is reduced in the mode of adjusting the operating power of the load based on the service life, so that the service life of the smoothing processing unit is guaranteed, and the reliability of the variable-frequency driving circuit is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of household appliances, in particular to a control method and device of a variable frequency drive circuit, an electric control box and an air conditioner. BACKGROUND

[0002] In the variable frequency drive circuit, the three-phase alternating voltage signal output by the power supply usually needs to be rectified by a rectifier bridge stack to obtain a direct current voltage signal, and then the direct current voltage signal is converted into a three-phase alternating voltage signal by an inverter circuit and output to the load.

[0003] In related technologies, in order to output a smooth three-phase alternating voltage signal to the load, the direct current voltage signal usually needs to be smoothed by a smoothing unit, and then input to the inverter circuit, wherein the smoothing unit includes elements such as electrolytic capacitors.

[0004] However, since the electrolytic capacitor has a certain impedance, it will generate heat, and the greater the ripple voltage in the direct current voltage signal, the more serious the heat generation, thereby greatly affecting the service life of the smoothing unit and reducing the reliability of the variable frequency drive circuit. SUMMARY

[0005] Therefore, the present application aims to provide a control method and device of a variable frequency drive circuit, an electric control box and an air conditioner to solve the technical problem that the service life of the smoothing unit in the variable frequency drive circuit is short in the prior art, thereby reducing the reliability of the variable frequency drive circuit.

[0006] To achieve the above-mentioned purpose, the technical solutions of the present application are as follows:

[0007] In a first aspect, the present application provides a control method of a variable frequency drive circuit, the variable frequency drive circuit comprising a rectifier bridge stack and a smoothing unit, and the control method comprising:

[0008] According to the direct current voltage signal output by the rectifier bridge stack, a ripple voltage signal in the direct current voltage signal is obtained; according to the ripple voltage signal, a first amplitude of an n-th harmonic signal corresponding to the direct current voltage signal is obtained, n being an integer greater than or equal to 2; according to the first amplitude, a remaining use time of the smoothing unit is determined, the smoothing unit being used to stabilize the direct current voltage signal; according to the first amplitude and the remaining use time, a target operating power of a load corresponding to the variable frequency drive circuit is determined, so that the load operates according to the target operating power.

[0009] In some embodiments, according to the first amplitude, the remaining use time of the smoothing unit is determined, comprising:

[0010] Obtaining a preset correspondence relationship, the preset correspondence relationship including a correspondence relationship between an amplitude and a remaining use time length; determining the remaining use time length of the smoothing processing unit according to the first amplitude and the preset correspondence relationship.

[0011] In some embodiments, the preset correspondence relationship includes a plurality of amplitudes and a use time length of each amplitude at a plurality of environmental temperatures, and determining the remaining use time length of the smoothing processing unit according to the first amplitude and the preset correspondence relationship includes:

[0012] Determining a plurality of use time lengths corresponding to the first amplitude at a plurality of environmental temperatures according to the first amplitude and the preset correspondence relationship; and determining the remaining use time length of the smoothing processing unit according to the plurality of use time lengths corresponding to the first amplitude at a plurality of environmental temperatures.

[0013] In some embodiments, determining the remaining use time length of the smoothing processing unit according to the plurality of use time lengths corresponding to the first amplitude at a plurality of environmental temperatures includes:

[0014] Obtaining a ratio of each use time length to a preset time length in the plurality of use time lengths; and determining the remaining use time length of the smoothing processing unit according to the plurality of use time lengths corresponding to the first amplitude at a plurality of environmental temperatures and the ratio corresponding to each use time length.

[0015] In some embodiments, determining the target operating power of the load corresponding to the variable frequency drive circuit according to the first amplitude and the remaining use time length includes: if it is determined that the remaining use time length is less than a time length threshold, determining the target operating power of the load according to the first amplitude; or if it is determined that the remaining use time length is greater than or equal to the time length threshold, determining the current operating power of the load as the target operating power.

[0016] In some embodiments, determining the target operating power of the load according to the first amplitude includes:

[0017] Determining a target power derating corresponding to the first amplitude according to a correspondence relationship between an amplitude and a power derating, and determining the target operating power of the load according to the current operating power of the load and the target power derating; or determining the operating power corresponding to the first amplitude as the target operating power of the load according to a correspondence relationship between an amplitude and an operating power.

[0018] In some embodiments, determining the remaining use time length of the smoothing processing unit according to the first amplitude includes:

[0019] Determining whether the first amplitude is less than a preset amplitude; and if so, determining the remaining use time length of the smoothing processing unit according to the first amplitude.

[0020] In some embodiments, when the first amplitude is greater than or equal to the preset amplitude, the method further includes: outputting warning information, the warning information being used to indicate that the temperature of the smoothing processing unit is higher than a safety temperature.

[0021] In some embodiments, the ripples voltage signal in the direct current voltage signal is obtained according to the direct current voltage signal output by the rectifier bridge stack, including:

[0022] The direct current voltage signal output by the rectifier bridge stack is obtained, the direct current voltage signal is filtered to obtain a direct current component in the direct current voltage signal, and the ripples voltage signal in the direct current voltage signal is determined according to the direct current voltage signal and the direct current component.

[0023] In some embodiments, the first amplitude of the n-th harmonic signal corresponding to the direct current voltage signal is obtained according to the ripples voltage signal, including:

[0024] The ripples voltage signal is notch filtered to extract a target harmonic signal in the ripples voltage signal, the target harmonic signal does not contain the n-th harmonic signal, the n-th harmonic signal corresponding to the direct current voltage signal is obtained according to the ripples voltage signal and the target harmonic signal, the orthogonal waveform corresponding to the n-th harmonic signal is obtained, and the first amplitude of the n-th harmonic signal is obtained by closed-loop adjustment of the amplitude according to the frequency and phase of the orthogonal waveform.

[0025] In some embodiments, the smoothing processing unit includes an electrolytic capacitor.

[0026] In a second aspect, the embodiments of the present application provide a control device of a variable frequency drive circuit, the variable frequency drive circuit including a rectifier bridge stack and a smoothing processing unit, and the control device including:

[0027] A first obtaining module is configured to obtain a ripples voltage signal in a direct current voltage signal according to the direct current voltage signal output by the rectifier bridge stack.

[0028] A second obtaining module is configured to obtain a first amplitude of an n-th harmonic signal corresponding to the direct current voltage signal according to the ripples voltage signal, n being an integer greater than or equal to 2.

[0029] A first determining module is configured to determine a remaining use duration of the smoothing processing unit according to the first amplitude, the smoothing processing unit being configured to stabilize the direct current voltage signal.

[0030] A second determining module is configured to determine a target operating power of a load corresponding to the variable frequency drive circuit according to the first amplitude and the remaining use duration, so that the load operates according to the target operating power.

[0031] In some embodiments, the first determining module is specifically configured to: obtain a preset corresponding relationship, the preset corresponding relationship including a corresponding relationship between the amplitude and the remaining use duration; and determine the remaining use duration of the smoothing processing unit according to the first amplitude and the preset corresponding relationship.

[0032] In some embodiments, the preset correspondence includes a plurality of amplitudes and a usage duration of each amplitude at a plurality of ambient temperatures, and the first determining module is specifically configured to: determine, according to the first amplitude and the preset correspondence, a plurality of usage durations of the first amplitude at the plurality of ambient temperatures; and determine the remaining usage duration of the smoothing processing unit according to the plurality of usage durations of the first amplitude at the plurality of ambient temperatures.

[0033] In some embodiments, the first determining module is specifically configured to: obtain a ratio of each usage duration in the plurality of usage durations to a preset duration; and determine the remaining usage duration of the smoothing processing unit according to the plurality of usage durations of the first amplitude at the plurality of ambient temperatures and the ratio corresponding to each usage duration.

[0034] In some embodiments, the second determining module is specifically configured to: if it is determined that the remaining usage duration is less than the duration threshold, determine the target operating power of the load according to the first amplitude; or if it is determined that the remaining usage duration is greater than or equal to the duration threshold, determine the target operating power of the load as the current operating power of the load.

[0035] In some embodiments, the second determining module is specifically configured to: determine a target power derating corresponding to the first amplitude according to the correspondence between the amplitude and the power derating, and determine the target operating power of the load according to the current operating power of the load and the target power derating; or determine the target operating power of the load as the operating power corresponding to the first amplitude according to the correspondence between the amplitude and the operating power.

[0036] In some embodiments, the first determining module is specifically configured to: determine whether the first amplitude is less than a preset amplitude; and if so, determine the remaining usage duration of the smoothing processing unit according to the first amplitude.

[0037] In some embodiments, the control device further includes an output module configured to output warning information, the warning information being configured to indicate that the temperature of the smoothing processing unit is higher than the safety temperature.

[0038] In some embodiments, the first obtaining module is specifically configured to: obtain a direct-current voltage signal output by the rectifier bridge stack; perform filtering processing on the direct-current voltage signal to obtain a direct-current component in the direct-current voltage signal; and determine a ripple voltage signal in the direct-current voltage signal according to the direct-current voltage signal and the direct-current component.

[0039] In some embodiments, the second obtaining module is specifically configured to: perform notch filtering processing on the ripple voltage signal to extract a target harmonic signal in the ripple voltage signal, the target harmonic signal not including an n-th harmonic signal; obtain the n-th harmonic signal corresponding to the direct-current voltage signal according to the ripple voltage signal and the target harmonic signal; obtain a quadrature waveform corresponding to the n-th harmonic signal; and perform closed-loop adjustment on the amplitude according to the frequency and phase of the quadrature waveform to obtain the first amplitude of the n-th harmonic signal.

[0040] In some embodiments, the smoothing processing unit comprises an electrolytic capacitor.

[0041] In a third aspect, the embodiments of the present application provide an electric control box, comprising: a load and a variable frequency drive circuit, the variable frequency drive circuit being connected with the load, and the variable frequency drive circuit being used for controlling operation of the load based on the control method of the first aspect.

[0042] In a fourth aspect, the embodiments of the present application provide an air conditioner, comprising: a processor, a memory and a variable frequency drive circuit; wherein the variable frequency drive circuit comprises a rectifier bridge stack and a smoothing processing unit, and the memory stores a computer program, and the processor executes the computer program to realize the control method of the first aspect.

[0043] In the control method of the variable frequency drive circuit provided by the embodiments of the present application, first, a ripple voltage signal in a direct current voltage signal output by the rectifier bridge stack is obtained according to the direct current voltage signal, then a first amplitude of an n-th harmonic signal corresponding to the direct current voltage signal is obtained according to the ripple voltage signal, then a remaining service life of the smoothing processing unit is determined according to the first amplitude, and finally, a target operation power of a load corresponding to the variable frequency drive circuit is determined according to the first amplitude and the remaining service life, so that the load operates according to the target operation power. In the scheme, the service life of the smoothing processing unit is derived from the amplitude of the direct current voltage signal, the influence on the smoothing processing unit is reduced by adjusting the operation power of the load based on the service life, so as to guarantee the service life of the smoothing processing unit, and further improve the reliability of the variable frequency drive circuit. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor based on the drawings shown.

[0045] Figure 1 The circuit structure schematic diagram of the variable frequency drive circuit provided by the embodiments of the present application is shown in the figure.

[0046] Figure 2 The flowchart of the control method of the variable frequency drive circuit provided by the embodiments of the present application is shown in the figure. Figure 1

[0047] Figure 3 The flowchart of the control method of the variable frequency drive circuit provided by the embodiments of the present application is shown in the figure. Figure 2

[0048] Figure 4 ​​Flowchart of control method of variable frequency driving circuit provided by the embodiment of the present application Figure 3 ;

[0049] Figure 5 Structure diagram of control device of variable frequency driving circuit provided by the embodiment of the present application

[0050] Figure 6 Structure diagram of air conditioner provided by the embodiment of the present application.

[0051] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0052] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0053] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative positional relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications will also change accordingly.

[0054] In addition, the description such as "first", "second" and the like in the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features.

[0055] In addition, the technical solutions of each embodiment of the present application can be combined with each other, but it must be based on the realization of the ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the scope of protection claimed by the present application.

[0056] Figure 1 Circuit structure diagram of variable frequency driving circuit provided by the embodiment of the present application. As shown in the figure, the variable frequency driving circuit comprises a power module 101, a rectifier bridge stack 102, a smoothing processing unit 103 and an inverter module 104, wherein the inverter module 104 is connected with the load. Figure 1

[0057] ​In some embodiments, the power module 101 is illustrated as a three-phase power supply, the voltage signal output by the power module 101 is rectified by the rectifier bridge stack 102 to obtain a 6-fold frequency pulsating voltage waveform, the pulsating voltage waveform is smoothed by the smoothing processing unit 103 to output a stable DC voltage signal, and the DC voltage signal is converted into a three-phase alternating current by the inverter module 104 and output to the load.

[0058] In actual applications, the smoothing processing unit in the smoothing processing unit 103, such as an electrolytic capacitor, usually needs thousands of uF to stabilize the DC bus voltage. However, due to the ESR impedance of these components, there will be a heating condition when the DC voltage signal is smoothed, which will seriously affect the service life of the smoothing processing unit.

[0059] The inventor found that the current city power is prone to phase imbalance, or the phase voltage is different due to load imbalance, which will exacerbate the ripple voltage in the smoothing processing unit, thereby exacerbating the heating condition of the smoothing processing unit, further affecting the service life of the smoothing processing unit, and reducing the reliability of the frequency conversion driving circuit. The waveform of the DC voltage signal output by the rectifier bridge stack side can reflect the above abnormal conditions of the power module, so the risk can be effectively identified in advance according to the harmonic components of the DC voltage signal, the risk of reducing the service life or even exploding due to overheating of the smoothing processing unit can be maximized, and the system reliability can be improved.

[0060] Therefore, the embodiments of the present application provide a control method, device, electric control box and air conditioner of a frequency conversion driving circuit. The ripple voltage signal in the frequency conversion driving circuit is obtained, and the amplitude of the n-th harmonic signal of the DC voltage signal is determined according to the ripple voltage signal, so that the service life of the smoothing processing unit is derived according to the amplitude, and the influence on the smoothing processing unit is reduced by adjusting the operating power of the load based on the service life, so as to prevent the service life of the smoothing processing unit from being affected by overheating of the smoothing processing unit, and to improve the reliability of the frequency conversion driving circuit.

[0061] Next, through specific embodiments, how the scheme provided by the embodiments of the present application solves the above technical problems will be described in detail.

[0062] Figure 2 The flowchart of the control method of the frequency conversion driving circuit provided by the embodiments of the present application Figure 1 .

[0063] As Figure 2 shown, the control method includes the following steps:

[0064] S201, according to the DC voltage signal output by the rectifier bridge stack, the ripple voltage signal in the DC voltage signal is obtained.

[0065] S202, obtain a first amplitude of an n-th harmonic signal corresponding to the direct current voltage signal according to the ripple voltage signal.

[0066] S203, determine a remaining use duration of the smoothing processing unit according to the first amplitude.

[0067] The smoothing processing unit can be an electrolytic capacitor.

[0068] S204, determine a target operation power of a load corresponding to the variable frequency drive circuit according to the first amplitude and the remaining use duration, so that the load operates according to the target operation power.

[0069] In the control method provided by the embodiments of the present application, the service life of the smoothing processing unit is derived from the amplitude of the direct current voltage signal, so as to reduce the influence on the smoothing processing unit by adjusting the operation power of the load based on the service life, thereby ensuring the service life of the smoothing processing unit and improving the reliability of the variable frequency drive circuit.

[0070] Figure 3 Flowchart of the control method of the variable frequency drive circuit provided by the embodiments of the present application Figure 2 On the basis of Figure 3 , the embodiments of the present application combine Figure 3 The steps S201-S202 in the above embodiments are described in more detail as follows. Figure 4 The control method comprises the following steps:

[0071] S301, obtain a direct current voltage signal output by a rectifier bridge stack.

[0072] S302, perform filtering processing on the direct current voltage signal to obtain a direct current component in the direct current voltage signal.

[0073] Specifically, the direct current component contained in the direct current voltage signal can be extracted by a low-pass filter.

[0074] S303, determine a ripple voltage signal in the direct current voltage signal according to the direct current voltage signal and the direct current component.

[0075] For the direct current voltage signal at each moment, the value of the ripple voltage signal at the moment can be obtained by subtracting the direct current component value corresponding to the moment from the voltage value of the direct current voltage signal at the moment, and then the ripple voltage signal is obtained.

[0076] S304, perform notch filtering processing on the ripple voltage signal to extract a target harmonic signal in the ripple voltage signal.

[0077] In this step, first, the ripple voltage signal is filtered through a notch filter to extract the harmonic components in the ripple voltage signal except the n-th harmonic signal, thereby obtaining an output voltage signal of the notch filter.

[0078] S305, obtaining the n-th harmonic signal corresponding to the direct current voltage signal according to the ripple voltage signal and the target harmonic signal.

[0079] Further, for the ripple voltage signal at each moment, the n-th harmonic signal value at each moment is obtained by subtracting the voltage value of the output voltage signal corresponding to the moment from the ripple voltage value at each moment in the ripple voltage signal, and then the n-th harmonic signal corresponding to the ripple voltage signal is obtained.

[0080] It should be noted that the value of n is not limited in the embodiments of the present application. For example, n can be 2, 3, 4, etc.

[0081] S306, obtaining the n-th harmonic signal corresponding to the n-th harmonic signal, and adjusting the amplitude in a closed loop according to the frequency and phase of the quadrature waveform to obtain the first amplitude of the n-th harmonic signal.

[0082] Specifically, the specific implementation scheme of the above step S306 is as follows:

[0083] (1) generating the quadrature waveform of the n-th harmonic signal through a second-order generalized integrator, and obtaining the frequency and phase information of the quadrature waveform of the n-th harmonic signal through a phase-locked loop;

[0084] (2) feeding back the frequency output by the phase-locked loop to the notch filter and the second-order generalized integrator to calculate the gain, thereby realizing the tracking of the power grid frequency;

[0085] (3) through the amplitude closed loop regulator, the voltage amplitude is subjected to coordinate transformation and amplitude projection based on the phase-locked loop output angle, and the error of the quadrature component is compared and subjected to amplitude feedback PI regulation, wherein the amplitude closed loop regulator can reduce the fluctuation of the output voltage amplitude through PI regulation, and can solve the problem that the voltage zero point cannot be calculated, thereby accurately obtaining the first amplitude corresponding to the n-th harmonic signal.

[0086] S307, determining the remaining use duration of the smoothing processing unit according to the first amplitude.

[0087] S308, determining the target operating power of the load corresponding to the frequency conversion driving circuit according to the first amplitude and the remaining use duration, so that the load operates according to the target operating power.

[0088] It should be noted that the specific implementation of steps S307 and S308 is shown in subsequent embodiments, which will not be described here.

[0089] Figure 3 Flowchart of the control method of the variable frequency drive circuit provided by the embodiment of the present application Figure 2 In Figure 3 And Figure 4 On the basis of Figure 4 The steps S203-S204 and S307-S308 in the above embodiments are described in more detail as follows Figure 5 The control method comprises the following steps:

[0090] S401, obtaining a ripple voltage signal in a direct current voltage signal according to a direct current voltage signal output by a rectifier bridge stack.

[0091] S402, obtaining a first amplitude of an n-th harmonic signal corresponding to the direct current voltage signal according to the ripple voltage signal.

[0092] It should be noted that the principles and beneficial effects of steps S401-S402 are similar to those of S301-S306 in Embodiment 3 described above, and specific reference can be made to the above embodiments, which will not be repeated here.

[0093] S403, determining whether the first amplitude is less than a preset amplitude.

[0094] S404, if not, outputting a warning information.

[0095] The warning information is used to indicate that the temperature of the smoothing processing unit is higher than the safe temperature, so that the user can make corresponding processing, for example, shutting down, replacing the smoothing processing unit, etc.

[0096] On the one hand, the preset amplitude is determined according to the safe temperature of the temperature of the smoothing processing unit. If the current first amplitude is greater than or equal to the preset amplitude, it indicates that the temperature of the smoothing processing unit has exceeded the safe temperature, and the service life of the smoothing processing unit will be greatly shortened, thereby seriously affecting the reliability of the variable frequency drive circuit. At this time, the warning information is issued to prompt the user to make relevant processing in time.

[0097] It should be understood that the present application does not make specific limitations on the way of outputting the warning information. For example, the warning information can be issued in the form of audible and visual alarm, SMS prompt, etc.

[0098] In addition, the sizes of the preset amplitudes corresponding to different types of variable frequency drive circuits are different, and the present application does not make specific limitations.

[0099] S405, if yes, determining the remaining use time length of the smoothing processing unit according to the first amplitude.

[0100] On the other hand, when the first amplitude is less than the preset amplitude, it indicates that the temperature of the smoothing processing unit is in the safe temperature, but the current temperature can still affect the service life of the smoothing processing unit, therefore, the service condition of the smoothing processing unit can be determined by calculating the service life (i.e. the remaining service time) of the smoothing processing unit under the working condition of the first amplitude, so as to perform corresponding processing.

[0101] Next, the determination scheme of the remaining service time of the smoothing processing unit is specifically explained through steps S406-S407:

[0102] S406, obtaining a preset corresponding relationship.

[0103] S407, determining the remaining service time of the smoothing processing unit according to the first amplitude and the preset corresponding relationship.

[0104] In some embodiments, the preset corresponding relationship includes the corresponding relationship between the amplitude and the remaining service time.

[0105] The inventors found that the service life (i.e. the remaining service time) of the smoothing processing unit is related to the environmental temperature. Therefore, in other embodiments, the preset relationship includes a plurality of amplitudes and the remaining service time of each amplitude under a plurality of environmental temperatures, and in this step, the service life (i.e. the remaining service time) of the smoothing processing unit under the working condition of the first amplitude can be determined according to the corresponding relationship.

[0106] Specifically, on the one hand, the remaining service time of each amplitude under a plurality of environmental temperatures is obtained according to the test of each amplitude under each test environmental temperature. For example, the test environmental temperatures are t1, t2, t3, t4 and t5, and in the above test environment, tests are performed at different amplitudes, so as to obtain the corresponding remaining service time B1, B2, B3, B4 and B5 of different amplitudes in the above test environmental temperatures.

[0107] On the other hand, the inventors also found that when the variable frequency drive circuit is in the working condition of the same amplitude, the service life of the smoothing processing unit is shorter as the environmental temperature rises, therefore, it can be concluded that the service life of the smoothing processing unit under different environmental temperature conditions when the variable frequency drive circuit is in the working condition of a certain specific amplitude.

[0108] Specifically, the above step S407 specifically includes the following steps:

[0109] (1) First, determine the plurality of service times corresponding to the first amplitude under a plurality of environmental temperatures according to the first amplitude and the above preset corresponding relationship.

[0110] Specifically, the service life of the smoothing processing unit corresponding to each environment temperature under different amplitude working conditions of the variable frequency driving circuit can be obtained according to the following formula, so as to obtain the preset corresponding relationship:

[0111] L x =L o ×2 (To-Tx) / 10 ×2 (△To-△Tx) / 5

[0112] L X The life value obtained by the calculation formula, L o The specification guarantee life value, T o The highest rated operating temperature (for example, 105℃), T X The actual environment temperature, that is, the actual environment temperature of the smoothing processing unit in the device, △T O The allowable central temperature rise, that is, the temperature rise of the smoothing processing unit when the ripple current rises to the rated value.

[0113] For example, the remaining use time of the smoothing processing unit corresponding to t1, t2, t3, t4 and t5 is A1, A2, A3, A4 and A5 respectively. It should be understood that the specific temperature values of t1, t2, t3, t4 and t5 are not limited in the embodiments of the present application. For example, t1, t2, t3, t4 and t5 are 35℃, 37℃, 48℃, 50℃ and 55℃ respectively.

[0114] (2) Further, according to the first amplitude and the preset corresponding relationship, the remaining use time corresponding to the first amplitude is obtained.

[0115] Optionally, since the variable frequency driving circuit is a variable working temperature operating device, the environment temperature is not constant during use, so when evaluating the service life of the smoothing processing unit, the comprehensive service life of the smoothing processing unit needs to be calculated according to the temperature change in the preset time period.

[0116] Specifically, first, the ratio of each use time to the preset time period is obtained, and then the remaining use time of the smoothing processing unit is determined according to the first amplitude and the multiple use times corresponding to the multiple environment temperatures.

[0117] For example, a representative climate model can be selected in the preset time period to calculate the time period ratio of each use time to the preset time period in the climate model. For example, the time period ratio of the use time of the smoothing processing unit under the temperatures t1, t2, t3, t4 and t5 to the preset time period is a1, a2, a3, a4 and a5 respectively. The comprehensive design life Y1 of the smoothing processing unit under the climate model can be obtained by the following formula:

[0118] Y1 = A1 x a1 + A2 x a2 + A3 x a3 + A4 x a4 + A5 x a5.

[0119] S408, determining whether the remaining usage duration is less than a duration threshold.

[0120] S409, if yes, determining the target operating power of the load according to the first amplitude;

[0121] The duration threshold can be the minimum duration of the smoothing processing unit in a safe condition, and when the remaining usage duration is less than the duration threshold, it means that the current smoothing processing unit has reached the expected service life, thereby greatly affecting the user experience. However, since the amplitude has not reached the warning standard at this time, the variable frequency drive circuit can be adjusted accordingly to reduce the impact of the service life due to the high temperature of the smoothing processing unit.

[0122] The inventor found that the impact of the amplitude on the smoothing processing unit can be reduced by limiting the output of the load, so the power of the load can be adjusted according to the current amplitude to extend the service life of the smoothing processing unit.

[0123] On the one hand, the corresponding relationship between the amplitude and the operating power of the load can be used to determine that the operating power corresponding to the first amplitude is the target operating power of the load.

[0124] On the other hand, the corresponding relationship between the amplitude and the power derating can also be used to determine the target power derating corresponding to the first amplitude, and then the target operating power of the load can be determined according to the current operating power of the load and the target power derating.

[0125] Specifically, the difference between the current operating power and the target power derating is determined as the target operating power of the load.

[0126] S410, if no, determining the current operating power of the load as the target operating power.

[0127] In some embodiments, when the remaining usage duration is greater than or equal to the duration threshold, it means that the current ripple voltage of the variable frequency drive circuit has less impact on the service life of the smoothing processing unit, that is, the current operating power of the load has less impact on the service life of the smoothing processing unit. Therefore, the current operating power of the load is determined as the target operating power.

[0128] In the embodiment of the present application, when the current amplitude of the variable frequency drive circuit is greater than or equal to the preset amplitude, the warning information is outputted, so as to timely remind the user to perform relevant processing, thereby ensuring the safety and reliability of the variable frequency drive circuit. In addition, when the current amplitude of the variable frequency drive circuit is less than the preset amplitude, the service life of the smoothing processing unit under the current working condition can be determined according to the amplitude, so that when the service life is less than the preset service life, the operating power of the load is timely adjusted, thereby improving the service life of the smoothing processing unit and further improving the reliability of the variable frequency drive circuit.

[0129] Figure 6 A structural schematic diagram of a control device of a variable frequency drive circuit is provided in the embodiment of the present application. The variable frequency drive circuit includes a smoothing processing unit and a rectifier bridge stack, and the control device 500 includes a first acquisition module 501, a second acquisition module 502, a first determination module 503, and a second determination module 504.

[0130] The first acquisition module 501 is configured to acquire a ripple voltage signal in a direct current voltage signal according to the direct current voltage signal outputted by the rectifier bridge stack.

[0131] The second acquisition module 502 is configured to acquire a first amplitude of an n-th harmonic signal corresponding to the direct current voltage signal according to the ripple voltage signal, where n is an integer greater than or equal to 2.

[0132] The first determination module 503 is configured to determine a remaining service time length of the smoothing processing unit according to the first amplitude, the smoothing processing unit being configured to stabilize the direct current voltage signal.

[0133] The second determination module 504 is configured to determine a target operating power of a load corresponding to the variable frequency drive circuit according to the first amplitude and the remaining service time length, so that the load operates according to the target operating power.

[0134] It should be noted that the control device of the variable frequency drive circuit provided in the embodiment can be used to execute the control method of the variable frequency drive circuit described above, and the implementation manner and technical effects are similar, which will not be described here in detail.

[0135] In some embodiments, the first determination module 503 is specifically configured to acquire a ratio of each service time length to a preset time length in a plurality of service time lengths.

[0136] The remaining service time length of the smoothing processing unit is determined according to the first amplitude in a plurality of service time lengths corresponding to a plurality of environmental temperatures and a ratio corresponding to each service time length.

[0137] In some embodiments, the second determination module 504 is specifically configured to determine the target operating power of the load according to the first amplitude if it is determined that the remaining service time length is less than a time length threshold; or

[0138] If it is determined that the remaining use duration is greater than or equal to the duration threshold, it is determined that the current running power of the load is the target running power.

[0139] In some embodiments, the first determination module 503 is specifically configured to determine whether the first amplitude is less than a preset amplitude.

[0140] If yes, the remaining use duration of the smoothing processing unit is determined according to the first amplitude.

[0141] In some embodiments, the control device 500 further includes an output module 505 configured to output warning information, the warning information being used to indicate that the temperature of the smoothing processing unit is higher than the safety temperature.

[0142] In some embodiments, the first acquisition module 501 is specifically configured to acquire a direct current voltage signal output by the rectifier bridge stack.

[0143] The direct current voltage signal is subjected to filtering processing to obtain a direct current component in the direct current voltage signal.

[0144] The ripple voltage signal in the direct current voltage signal is determined according to the direct current voltage signal and the direct current component.

[0145] In some embodiments, the second acquisition module 502 is specifically configured to perform notch filtering processing on the ripple voltage signal to extract a target harmonic signal in the ripple voltage signal, the target harmonic signal not containing the n-th harmonic signal.

[0146] The n-th harmonic signal corresponding to the direct current voltage signal is obtained according to the ripple voltage signal and the target harmonic signal.

[0147] The first amplitude of the n-th harmonic signal is obtained by acquiring a quadrature waveform corresponding to the n-th harmonic signal and performing closed-loop adjustment on the amplitude according to the frequency and phase of the quadrature waveform.

[0148] In some embodiments, the smoothing processing unit includes an electrolytic capacitor.

[0149] Figure 6 A structural schematic diagram of an air conditioner is provided for the embodiments of the present application. As shown in the structural schematic diagram of the air conditioner 600, the air conditioner 600 includes a processor 601, a memory 602, and a variable frequency drive circuit 603. ​

[0150] The variable frequency drive circuit 603 includes a smoothing processing unit and a rectifier bridge stack, and the memory 602 stores a computer program; the processor 601 executes the computer program stored in the memory to implement the control method of the variable frequency drive circuit in the above-mentioned method embodiments.

[0151] ​The memory 602 and the processor 601 are electrically connected through direct or indirect connection to realize data transmission or interaction. For example, the elements can be electrically connected through one or more communication buses or signal lines, such as through the bus 604. The memory 602 stores computer execution instructions for implementing the data access control method, including at least one software function module stored in the memory in the form of software or firmware. The processor 601 executes various function applications and data processing by running the software program and the module stored in the memory 602.

[0152] The memory 602 can be, but is not limited to, a random access memory (RAM), a read only memory (ROM), a programmable read only memory (PROM), an erasable programmable read only memory (EPROM), an electrically erasable programmable read only memory (EEPROM), etc. The memory is used to store programs. After receiving an execution instruction, the processor executes the program. Further, the software program and the module in the memory can also include an operating system, which can include various software components and / or drivers for managing system tasks (such as memory management, storage device control, power management, etc.) and can communicate with various hardware or software components to provide an operating environment for other software components.

[0153] The processor 601 can be an integrated circuit chip with signal processing capability. The processor 601 can be a general purpose processor, including a central processing unit (CPU), a network processor (NP), etc. It can implement or execute the disclosed methods, steps and logic block diagrams in the embodiments of the present application. The general purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0154] It should be noted that the air conditioner in the embodiments of the present application can be various types of air conditioners, such as central air conditioners, vertical air conditioners, hanging air conditioners, etc. In some embodiments, the air conditioner can also include some parts of the above-mentioned air conditioners, such as air conditioner outdoor units, air conditioner indoor units, etc. In the embodiments, the air conditioner can also include multiple indoor units or multiple outdoor units, which are not listed one by one.

[0155] The embodiment of the present application also provides an electric control box, comprising a load and a variable frequency drive circuit as in the above embodiment, the variable frequency drive circuit comprising a smoothing processing unit and a rectifier bridge stack, the variable frequency drive circuit being connected with the load, and the variable frequency drive circuit being used for controlling the operation of the load based on the control method of the above method embodiment.

[0156] The embodiment of the present application also provides a computer readable storage medium, wherein the computer readable storage medium stores computer execution instructions, and the processor is used for implementing the control method of the variable frequency drive circuit in the above method embodiment when executing the computer instructions.

[0157] The embodiment of the present application also provides a computer program product, comprising a computer program, and the computer program is used for implementing the control method of the variable frequency drive circuit provided in the above method embodiment when executed by the processor.

[0158] Those skilled in the art can understand that all or part of the processes in the above method embodiments can be completed by a computer program instructing related hardware, and the computer program can be stored in a non-volatile computer readable storage medium, and the computer program can include the processes of the above method embodiments when executed. Any reference to memory, storage, database or other medium in each embodiment provided by the present application can include non-volatile and / or volatile memory. The non-volatile memory can include read only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. The volatile memory can include random access memory (RAM) or external cache memory. As an illustration but not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0159] In several embodiments provided in the present application, it should be understood that the disclosed apparatus and method can be implemented in other manners. For example, the division of the units is only a logical function division, and there can be another division manner for the actual implementation, for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections between the units can be indirect couplings or communication connections through some interfaces, devices or units, and can be in electrical, mechanical or other forms.

[0160] So far, the technical solutions of the present application have been described in combination with the preferred embodiments shown in the drawings, but it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the present application, and the technical solutions after the changes or replacements will all fall within the protection scope of the present application.

Claims

1. A control method of a variable frequency drive circuit, characterized by, The variable frequency drive circuit comprises a rectifier bridge stack and a smoothing processing unit, and the control method comprises: According to the direct current voltage signal output by the rectifier bridge stack, a ripple voltage signal in the direct current voltage signal is obtained; According to the ripple voltage signal, a first amplitude of an n-th harmonic signal corresponding to the direct current voltage signal is obtained, n being an integer greater than or equal to 2; According to the first amplitude, a remaining use duration of the smoothing processing unit is determined, the smoothing processing unit being used for stabilizing the direct current voltage signal; According to the first amplitude and the remaining use duration, a target operating power of a load corresponding to the variable frequency drive circuit is determined, so that the load operates according to the target operating power; The determination of the remaining use duration of the smoothing processing unit according to the first amplitude comprises: A preset corresponding relationship is obtained, the preset corresponding relationship comprising a corresponding relationship between amplitudes and remaining use durations; According to the first amplitude and the preset corresponding relationship, the remaining use duration of the smoothing processing unit is determined.

2. The control method according to claim 1, characterized by, The preset corresponding relationship comprises a plurality of amplitudes and use durations of each amplitude at a plurality of environmental temperatures, and the determination of the remaining use duration of the smoothing processing unit according to the first amplitude and the preset corresponding relationship comprises: According to the first amplitude and the preset corresponding relationship, a plurality of use durations corresponding to the first amplitude at the plurality of environmental temperatures are determined; According to the plurality of use durations corresponding to the first amplitude at the plurality of environmental temperatures, the remaining use duration of the smoothing processing unit is determined.

3. The control method according to claim 2, characterized by, The determination of the remaining use duration of the smoothing processing unit according to the plurality of use durations corresponding to the first amplitude at the plurality of environmental temperatures comprises: A ratio of each use duration to a preset duration in the plurality of use durations is obtained; According to the plurality of use durations corresponding to the first amplitude at the plurality of environmental temperatures and the ratio of each use duration, the remaining use duration of the smoothing processing unit is determined.

4. The control method according to any one of claims 1 to 3, characterized by, The determination of the target operating power of the load according to the first amplitude and the remaining use duration comprises: If it is determined that the remaining use duration is less than a duration threshold, the target operating power of the load is determined according to the first amplitude; or If it is determined that the remaining use duration is greater than or equal to the duration threshold, a current operating power of the load is determined as the target operating power.

5. The control method according to claim 4, characterized by The determination of the target operating power of the load according to the first amplitude comprises: According to a corresponding relationship between amplitudes and power derating, a target power derating corresponding to the first amplitude is determined, and according to a current operating power of the load and the target power derating, the target operating power of the load is determined; or According to a corresponding relationship between amplitudes and operating powers, an operating power corresponding to the first amplitude is determined as the target operating power of the load.

6. The control method according to any one of claims 1 to 3, characterized by, The determination of the remaining use duration of the smoothing processing unit according to the first amplitude comprises: It is determined whether the first amplitude is less than a preset amplitude; If yes, the remaining use duration of the smoothing processing unit is determined according to the first amplitude.

7. The control method according to claim 6, characterized by When the first amplitude is greater than or equal to the preset amplitude, the method further comprises: outputting warning information, the warning information being used to indicate that the temperature of the smoothing processing unit is higher than a safety temperature.

8. The control method according to any one of claims 1 to 3, characterized by, The DC voltage signal output by the rectifier bridge stack is acquired to obtain a ripple voltage signal in the DC voltage signal, including: acquiring a DC voltage signal output by the rectifier bridge stack; filtering the DC voltage signal to obtain a DC component in the DC voltage signal; determining the ripple voltage signal in the DC voltage signal according to the DC voltage signal and the DC component.

9. The control method according to any one of claims 1 to 3, characterized by, The first amplitude of the n-th harmonic signal corresponding to the DC voltage signal is acquired according to the ripple voltage signal, including: notch filtering the ripple voltage signal to extract a target harmonic signal in the ripple voltage signal, the target harmonic signal not containing the n-th harmonic signal; acquiring the n-th harmonic signal corresponding to the DC voltage signal according to the ripple voltage signal and the target harmonic signal; acquiring a quadrature waveform corresponding to the n-th harmonic signal, and performing closed-loop adjustment on the amplitude according to the frequency and phase of the quadrature waveform to obtain the first amplitude of the n-th harmonic signal.

10. The control method according to any one of claims 1 to 3, characterized by, The smoothing processing unit comprises an electrolytic capacitor.

11. A control device of a variable frequency drive circuit, characterized by comprising: The frequency conversion driving circuit comprises a rectifier bridge stack and a smoothing processing unit, and the control device comprises: a first acquisition module configured to acquire a ripple voltage signal in a DC voltage signal output by the rectifier bridge stack; a second acquisition module configured to acquire a first amplitude of an n-th harmonic signal corresponding to the DC voltage signal according to the ripple voltage signal, n being an integer greater than or equal to 2; a first determination module configured to determine a remaining use duration of the smoothing processing unit according to the first amplitude, the smoothing processing unit being configured to stabilize the DC voltage signal; a second determination module configured to determine a target operating power of a load corresponding to the frequency conversion driving circuit according to the first amplitude and the remaining use duration, so that the load operates according to the target operating power; the first determination module is further configured to: acquire a preset corresponding relationship, the preset corresponding relationship comprising a corresponding relationship between an amplitude and a remaining use duration; determine the remaining use duration of the smoothing processing unit according to the first amplitude and the preset corresponding relationship.

12. An electric control box characterized by comprising: The electric control box comprises a load and a frequency conversion driving circuit, the frequency conversion driving circuit being connected to the load, and the frequency conversion driving circuit being configured to control the operation of the load based on the control method of claims 1-10.

13. An air conditioner characterized by comprising: The air conditioner comprises a processor, a memory and a frequency conversion driving circuit; wherein the frequency conversion driving circuit comprises a rectifier bridge stack and a smoothing processing unit, the memory stores a computer program, and the processor executes the computer program to implement the control method of claims 1-10.

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