Motor current distortion detection method and device, medium and air conditioner

Abstract

The invention discloses a current distortion detection method and device for a motor, a medium and an air conditioner, and the method comprises the steps: obtaining a real-time sampling current, generating a real-time reference current, calculating the point-by-point deviation of the real-time sampling current and the reference current in each detection period, and judging a current distortion state according to the deviation. According to the method, point-by-point deviation analysis is carried out in a detection period in real time, a complete electrical period needed by traditional harmonic analysis is replaced, distortion judgment can be completed only within a short period of time in the detection period, and detection delay is remarkably reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular, to a method, device, medium, and air conditioner for detecting current distortion of a motor. Background Art

[0002] In an air conditioning system, as a core component, the monitoring and control of current distortion of the motor directly affect the reliability, energy efficiency, and user experience of the system. However, when detecting current distortion using traditional harmonic analysis methods, there is a relatively high delay. In the case of instantaneous overload, the motor may be damaged before the detection is completed. Summary of the Invention

[0003] Based on this, it is necessary to provide a method, device, medium, and air conditioner for detecting current distortion of a motor to solve the problem of relatively high delay in detecting current distortion of a motor in the prior art.

[0004] In a first aspect, an embodiment of the present application provides a method for detecting current distortion of a motor, the method including:

[0005] Obtaining a real-time sampled current of the motor and generating a corresponding real-time reference current according to the real-time sampled current;

[0006] Calculating a current deviation between a first sampling point of the real-time sampled current and a second sampling point of the real-time reference current at the same sampling moment within each detection period;

[0007] Determining the current distortion state of the motor according to the current deviation.

[0008] In some embodiments of the present application, the real-time sampled current includes a first sampled current of a compressor motor and a second sampled current of a fan motor sampled synchronously, and the real-time reference current includes a first reference current corresponding to the first sampled current and a second reference current corresponding to the second sampled current. The generating a corresponding real-time reference current according to the real-time sampled current includes:

[0009] Generating a first reference current corresponding to the first sampled current through a first phase-locked loop;

[0010] Generating a second reference current corresponding to the second sampled current through a second phase-locked loop.

[0011] In some embodiments of the present application, the first phase-locked loop includes a second-order adaptive phase-locked loop. The generating a first reference current corresponding to the first sampled current through the first phase-locked loop includes:

[0012] Obtaining a first real-time rotational speed of the compressor motor;

[0013] Based on the first real-time rotational speed and the first sampled current, the first phase of the first reference current is iteratively generated through the second-order adaptive phase-locked loop; wherein the second-order adaptive phase-locked loop includes a phase discriminator term and a rotational speed feedforward compensation term;

[0014] Determine the first amplitude of the first reference current at the first real-time rotational speed according to the rotational speed-amplitude mapping table;

[0015] Generate a first reference current synchronized with the first sampled current based on the first phase and the first amplitude.

[0016] In some embodiments of the present application, the second phase-locked loop includes a quadrature signal generator based on a coordinate rotation digital calculation algorithm. The generation of the second reference current corresponding to the second sampled current through the second phase-locked loop includes:

[0017] Obtain the second real-time rotational speed of the fan motor;

[0018] Utilize the quadrature signal generator to dynamically adjust the phase-locking rate according to the second real-time rotational speed and the frequency characteristics of the second sampled current, and iteratively generate the second phase of the second reference current;

[0019] Determine the second amplitude of the second reference current at the second real-time rotational speed according to the rotational speed-amplitude mapping table;

[0020] Generate a second reference current synchronized with the second sampled current based on the second phase and the second amplitude.

[0021] In some embodiments of the present application, the determination of the current distortion state of the motor according to the current deviation includes:

[0022] If the current deviation of the target sampling point is greater than the target deviation threshold, then take the target sampling point as a distortion risk point; wherein, the target sampling point is any sampling point within the target detection period, and the target detection period is any detection period of the motor;

[0023] Determine the risk score of the target detection period according to the total number of risk points of the distortion risk points within the target detection period;

[0024] Determine the current distortion state of the motor in the target detection period according to the risk score and the score-distortion state mapping relationship.

[0025] In some embodiments of the present application, the determination method of the target deviation threshold includes:

[0026] Obtain a preset reference deviation threshold and an environmental compensation value; wherein, the environmental compensation value has a negative correlation with the environmental temperature;

[0027] Determine the target deviation threshold according to the environmental compensation value and the reference deviation threshold.

[0028] In some embodiments of the present application, after determining the current distortion state of the motor according to the current deviation, the following steps are further included:

[0029] If the current distortion state triggers a frequency reduction operation, the frequency of the motor is reduced by a frequency retraction algorithm; wherein, the frequency retraction algorithm includes:

[0030]

[0031] In the above formula, f new is the frequency after the frequency reduction of the motor; f current is the current operating frequency of the motor; Δf is the frequency adjustment step; Counter is the risk score; C threshold is the score threshold for triggering the frequency reduction operation; a is a preset coefficient.

[0032] In a second aspect, an embodiment of the present application further provides a current distortion detection device for a motor, and the current distortion detection device for the motor includes:

[0033] A generation module, configured to obtain the real-time sampled current of the motor and generate a corresponding real-time reference current according to the real-time sampled current;

[0034] A deviation calculation module, configured to calculate the current deviation between the first sampling point of the real-time sampled current and the second sampling point of the real-time reference current at the same sampling moment in each detection period;

[0035] A distortion detection module, configured to determine the current distortion state of the motor according to the current deviation.

[0036] In a third aspect, an embodiment of the present application further provides an air conditioner, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, the steps in the above-mentioned current distortion detection method for the motor are implemented.

[0037] In a fourth aspect, an embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by the processor, the steps in the above-mentioned current distortion detection method for the motor are implemented.

[0038] In a fifth aspect, an embodiment of the present application further provides a computer program product or a computer program. The computer program product or the computer program includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the methods provided in the various alternative implementations described in the embodiments of the present application.

[0039] The present invention provides a method, a device, a medium, and an air conditioner for detecting current distortion of a motor. By obtaining real-time sampled current and generating a real-time reference current, the point-by-point deviation between the real-time sampled current and the reference current is calculated in each detection period, and the current distortion state is determined based on the deviation. This method analyzes the point-by-point deviation in real time within the detection period, replacing the complete electrical cycle required for traditional harmonic analysis, and can complete the distortion determination only within a short period of time in the detection period, significantly reducing the detection delay. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0041] Among them:

[0042] Figure 1 is a schematic flowchart of the method for detecting current distortion of a motor provided in the first embodiment of the present application;

[0043] Figure 2 is a schematic flowchart of the method for detecting current distortion of a motor provided in the second embodiment of the present application;

[0044] Figure 3 is a schematic structural diagram of the device for detecting current distortion of a motor;

[0045] Figure 4 is a structural block diagram of an air conditioner. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0046] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0047] In the description, claims and the above drawings of the present application, terms such as "first", "second", etc. are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally further include steps or units not listed, or may optionally further include other steps or units inherent to these processes, methods, products or devices.

[0048] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0049] Please refer to Figure 1 , Figure 1 FIG. is a schematic flowchart of a method for detecting current distortion of a motor provided in the first embodiment of the present application. Although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown in the drawings. Specifically, the specific process of the method for detecting current distortion of the motor provided in the first embodiment of the present application is as follows:

[0050] S101, obtain the real-time sampled current of the motor, and generate a corresponding real-time reference current according to the real-time sampled current.

[0051] Among them, the real-time sampled current refers to the signal data that continuously reflects the actual current value of the motor during the operation of the motor. The real-time reference current refers to an idealized current signal generated based on the real-time sampled current through mathematical modeling or signal processing methods, and is used as a comparison benchmark to detect current distortion.

[0052] Optionally, the current signal of the motor is continuously collected by a high-precision current sensor (such as a Hall effect sensor) installed in the motor circuit at a fixed sampling frequency (such as 10 kHz) to obtain the real-time sampled current. Then, a digital signal processor is used to extract the fundamental wave component of the real-time sampled current, and an idealized sine wave signal is constructed in combination with the rated parameters of the motor (such as rated frequency and amplitude) as the real-time reference current.

[0053] Optionally, when obtaining the real-time sampled current, a dynamic gain amplifier can also be integrated in the signal conditioning circuit between the current sensor and the analog-to-digital converter (ADC). This amplifier monitors the fluctuation of the bus voltage in real time and automatically adjusts the amplification factor according to the voltage change, so that the amplitude of the ADC input signal is always maintained between 60% and 90% of the ADC range to optimize the signal resolution. Moreover, a third-order Butterworth low-pass filter is embedded in the signal conditioning circuit. This filter processes the acquired real-time sampled current signal to eliminate the switching noise generated by the high-frequency switching action in the motor drive circuit and ensure the smoothness and stability of the output signal.

[0054] S102. During each detection period, calculate the current deviation between the first sampling point of the real-time sampled current and the second sampling point of the real-time reference current at the same sampling moment.

[0055] Herein, the detection period refers to a time period used to analyze the real-time sampled current and the real-time reference current. This detection period can be a time period with a fixed duration or a time period containing a fixed number of sampling points, and no specific limitation is made here. The current deviation refers to the numerical difference between the first sampling point of the real-time sampled current and the second sampling point of the real-time reference current at the same sampling moment. This current deviation can be the absolute value of the difference between the first sampling point and the second sampling point or the percentage of the difference between the first sampling point and the second sampling point, and no specific limitation is made here.

[0056] Optionally, each detection period contains n sampling points, where n≥2. Each sampling point corresponds to a sampling moment. For each sampling moment, extract the value of the first sampling point of the real-time sampled current and the value of the second sampling point of the real-time reference current. Calculate the current deviation between the two using the difference formula: current deviation = |first sampling point value - second sampling point value| to obtain the absolute deviation value of this sampling point. Repeat this process until the deviation values of all n sampling points within the detection period are calculated.

[0057] It can be understood that traditional harmonic analysis methods require at least one complete electrical cycle (such as a sine or cosine cycle) to complete the detection, while this method only requires a short period of time (one detection period) within the electrical cycle and does not require a complete cycle, thus significantly reducing the detection delay.

[0058] S103. Determine the current distortion state of the motor according to the current deviation.

[0059] Herein, the current distortion state refers to the determination result of whether the motor current signal deviates from the normal operating state and is used to reflect whether there are abnormal fluctuations or harmonic interferences in the current. The current distortion state can include but is not limited to being divided into a normal state and a distortion state, and no specific limitation is made here.

[0060] Optionally, first set a predefined deviation threshold (for example, 5% of the rated current of the motor), which is determined according to the operating parameters and application scenarios of the motor. For the n sampling points within the detection period (for example, n = 10), compare the current deviation value of each sampling point with the preset threshold one by one. If the deviation values of more than a (for example, a = 3) sampling points exceed the threshold, it is determined that the current distortion state of the motor within the detection period is the "distortion state"; otherwise, it is determined as the "normal state".

[0061] In the above embodiment, by acquiring the real-time sampled current and generating the real-time reference current, the point-by-point deviation between the real-time sampled current and the reference current is calculated within each detection period, and the current distortion state is determined according to the deviation. This method analyzes the point-by-point deviation in real time within the detection period, replacing the complete electrical cycle required for traditional harmonic analysis, and can complete the distortion determination only within a short period of time within the detection period, significantly reducing the detection delay.

[0062] Please refer to Figure 2 , Figure 2 which is a schematic flow chart of the method for detecting current distortion of the motor provided by the second embodiment of the present application. Although the logical order is shown in the flow chart, in some cases, the steps shown or described may be executed in a different order from that shown in the drawings. Specifically, the specific flow of the method for detecting current distortion of the motor provided by the second embodiment of the present application is as follows:

[0063] S201, acquire the real-time sampled current of the motor, and generate the corresponding real-time reference current according to the real-time sampled current.

[0064] Considering that in an air-conditioning system, when the compressor motor and the fan motor operate together, if current distortion occurs in both motors simultaneously, the system is likely to misjudge the coupled current as a fault of a single motor. Especially in the low-frequency band, due to electromagnetic resonance, the false alarm frequency increases significantly. The existing single-channel monitoring scheme is difficult to effectively distinguish the interactive harmonic interference between the compressor motor and the fan motor, resulting in a relatively high misjudgment rate of multi-motor coupled interference.

[0065] In view of the above problems, in some embodiments of the present application, the real-time sampled current includes the first sampled current of the compressor motor and the second sampled current of the fan motor sampled synchronously, and the real-time reference current includes the first reference current corresponding to the first sampled current and the second reference current corresponding to the second sampled current. Generating the corresponding real-time reference current according to the real-time sampled current in S201 specifically includes the following steps:

[0066] S2011, acquire the first sampled current of the compressor motor and the second sampled current of the fan motor sampled synchronously.

[0067] Optionally, in the air conditioning system, synchronous sampling of the three-phase currents of the compressor motor and the fan motor is achieved by configuring a magnetic balance Hall sensor. Specifically, magnetic balance Hall sensors are respectively installed in the three-phase power supply lines of the compressor motor and the fan motor, and one sensor is configured for each phase line. A unified sampling frequency is set, and the sampling moments of all sensors are ensured to be consistent through an internal clock synchronization mechanism. During the sampling process, the sensor measures the three-phase current of the compressor motor in real time as the first sampled current; at the same time, it measures the three-phase current of the fan motor as the second sampled current.

[0068] S2012, generate a first reference current corresponding to the first sampled current through a first phase-locked loop.

[0069] Optionally, the first phase-locked loop first extracts the phase and frequency information of the first sampled current through a phase detector, and then uses a voltage-controlled oscillator to generate a sine wave signal synchronized with the input signal. The amplitude of this sine wave is calibrated according to the rated current parameter of the compressor motor to ensure consistency with the actual operating conditions. The generated sine wave signal is the first reference current.

[0070] In some embodiments of the present application, the first phase-locked loop includes a second-order adaptive phase-locked loop. S2012 generates a first reference current corresponding to the first sampled current through the first phase-locked loop, which specifically includes the following steps:

[0071] S2012a, obtain the first real-time speed of the compressor motor.

[0072] Wherein, the first real-time speed refers to the real-time rotor speed of the compressor motor during operation, expressed in revolutions per minute (RPM).

[0073] Optionally, a Hall sensor is configured to be installed near the rotor of the compressor motor. This sensor measures the change in the rotor magnetic pole position at a fixed frequency (for example, 10 kHz), and calculates the rotor rotation period through a data acquisition system, and then converts it to obtain the first real-time speed.

[0074] S2012b, based on the first real-time speed and the first sampled current, iteratively generate the first phase of the first reference current through a second-order adaptive phase-locked loop.

[0075] Wherein, the second-order adaptive phase-locked loop includes a phase discriminator term and a speed feed-forward compensation term. The speed feed-forward compensation term refers to the compensation amount based on speed introduced in the phase calculation of the phase-locked loop, which is used to offset the phase lag caused by sudden load changes.

[0076] Optionally, input the first sampled current collected by S2011 and the first real-time speed obtained by S2012a into the second-order adaptive phase-locked loop to iteratively generate the first phase of the first reference current. The second-order adaptive phase-locked loop is expressed as:

[0077]

[0078] In the above formula, θ comp (k + 1) is the phase of the (k + 1)-th sampling point; θ comp (k) is the phase of the k-th sampling point; K p is the adjustment coefficient; e phase is the phase error; RPM is the rotational speed; Ts is the sampling period; K p *e phase corresponds to the phase discriminator term; corresponds to the rotational speed feedforward compensation term.

[0079] Here, a second-order adaptive phase-locked loop is used to generate the first phase because the phase discriminator in it can quickly track phase changes. And since load mutations may cause phase lags, and the rotational speed feedforward compensation in it can offset this phase lag, thereby improving the dynamic response of phase estimation.

[0080] S2012c. Determine the first amplitude of the first reference current at the first real-time rotational speed according to the rotational speed - amplitude mapping table.

[0081] Among them, the rotational speed - amplitude mapping table refers to a data table pre-stored in the embedded chip, which records the corresponding relationship of the rated current peak value of the compressor motor at different rotational speeds.

[0082] Optionally, obtain the pre-stored rotational speed - amplitude mapping table, which is obtained through laboratory calibration and records the rated current peak values of the compressor motor at different rotational speeds. Based on the first real-time rotational speed in step S2012a, find the corresponding current peak value from the mapping table as the initial first amplitude.

[0083] Furthermore, the real-time fluctuation of the bus voltage (±15% of the rated value) can also be monitored, and the first amplitude is dynamically adjusted through an amplitude correction algorithm (for example, proportional adjustment) to ensure that the amplitude error is less than 3%. By such real-time correction, the accuracy of the reference current is ensured.

[0084] S2012d. Generate a first reference current synchronized with the first sampled current based on the first phase and the first amplitude.

[0085] Optionally, based on the first phase generated in step S2012b and the first amplitude determined in step S2012c, construct a sine wave signal: where A is the first amplitude, is the first phase. This sine wave signal I ref1 is the first reference current, and its fundamental frequency and sampling frequency are the same as those of the first sampled current.

[0086] In S2012a - S2012d above, an ideal signal highly synchronized with the first sampled current is generated through the first phase - locked loop, providing a high - quality comparison benchmark for subsequent current distortion detection.

[0087] S2013: Generate a second reference current corresponding to the second sampled current through a second phase - locked loop.

[0088] Optionally, the second phase - locked loop first extracts the phase and frequency information of the second sampled current through a phase detector, and then uses a voltage - controlled oscillator to generate a sine - wave signal synchronized with the input signal. The amplitude of this sine wave is calibrated according to the rated current parameters of the compressor motor to ensure consistency with the actual operating conditions. The generated sine - wave signal is the second reference current.

[0089] In some embodiments of the present application, the second phase - locked loop includes an orthogonal signal generator based on the Coordinate Rotation Digital Computer (CORDIC) algorithm. Generating the second reference current corresponding to the second sampled current through the second phase - locked loop specifically includes the following steps:

[0090] S2013a: Obtain the second real - time rotational speed of the fan motor.

[0091] The second real - time rotational speed refers to the real - time rotor rotational speed of the fan motor during operation, expressed in revolutions per minute (RPM).

[0092] Optionally, extract the real - time duty - cycle data from the PWM drive module of the fan motor. Then, based on the pre - calibrated correspondence between the duty cycle and the rotational speed, the real - time rotational speed of the fan motor is deduced inversely.

[0093] S2013b: Use the orthogonal signal generator to dynamically adjust the phase - locking rate according to the second real - time rotational speed and the frequency characteristics of the second sampled current, and iteratively generate the second phase of the second reference current.

[0094] Optionally, input the second sampled current collected in S2011 and the second real - time rotational speed obtained in S2013a into the second phase - locked loop, which includes an orthogonal signal generator based on the CORDIC algorithm. The orthogonal signal generator dynamically adjusts the phase - locking rate according to the frequency characteristics of the second sampled current and the second real - time rotational speed to generate sine and cosine signals, then calculates the phase error between the second sampled current and the current phase estimates of the sine and cosine signals, and generates the second phase of the second reference current through iterative update.

[0095] Here, the CORDIC orthogonal signal generator is used to generate the second phase because the CORDIC algorithm can efficiently calculate sine and cosine functions and is suitable for real - time processing in embedded systems. And since the frequency of the fan motor current may fluctuate due to changes in rotational speed, dynamically adjusting the phase - locking rate can improve the phase - tracking accuracy.

[0096] S2013c. Determine the second amplitude of the second reference current at the second real-time rotational speed according to the rotational speed-amplitude mapping table.

[0097] Optionally, obtain the pre-stored rotational speed-amplitude mapping table. Based on the second real-time rotational speed in step S2013a, find the corresponding current peak value from the mapping table as the initial second amplitude.

[0098] Furthermore, the real-time fluctuation of the bus voltage (±15% of the rated value) can also be monitored, and the second amplitude is dynamically adjusted through an amplitude correction algorithm (e.g., proportional adjustment) to ensure that the amplitude error is less than 3%. Such real-time correction ensures the accuracy of the reference current.

[0099] S2013d. Generate a second reference current synchronized with the second sampled current based on the second phase and the second amplitude.

[0100] Optionally, based on the second phase generated in step S2013b and the second amplitude determined in step S2013c, construct a sine wave signal: where B is the second amplitude, is the second phase. This sine wave signal I ref2 is the second reference current, and its fundamental frequency and sampling frequency are the same as those of the second sampled current.

[0101] In the above S2013a - S2013d, an ideal signal highly synchronized with the second sampled current is generated through the second phase-locked loop, providing a high-quality comparison benchmark for subsequent current distortion detection.

[0102] In the above S2011 - S2013, independent first and second phase-locked loops are used to generate reference currents strictly synchronized with the rotational speeds of the compressor motor and the fan motor respectively, realizing dual-channel decoupled analysis, thereby effectively solving the problem of harmonic coupling interference in a multi-motor system.

[0103] S202. Calculate the current deviation between the first sampling point of the real-time sampled current and the second sampling point of the real-time reference current at the same sampling moment in each detection cycle.

[0104] In some embodiments of the present application, S202 in the current distortion detection method of the motor provided in the second embodiment is basically the same in principle as S102 in the current distortion detection method of the motor provided in the first embodiment. The difference is that in this embodiment, it is necessary to calculate the current deviation between the first sampling point of the first sampled current and the second sampling point of the first reference current at the same sampling moment, and calculate the current deviation between the first sampling point of the second sampled current and the second sampling point of the second reference current at the same sampling moment. The specific calculation process will not be elaborated here.

[0105] S203. If the current deviation of the target sampling point is greater than the target deviation threshold, then the target sampling point is regarded as a distortion risk point.

[0106] Among them, the target sampling point is any sampling point within the target detection period, and the target detection period is any detection period of the motor, and this motor can be either a compressor motor or a fan motor. It can be understood that if a certain sampling is determined as a distortion risk point, it indicates that there is a potential current distortion risk at this sampling point.

[0107] In some embodiments of the present application, the determination method of the target deviation threshold includes:

[0108] S2031. Obtain a preset reference deviation threshold and an environmental compensation value.

[0109] Among them, the reference deviation threshold is a standard value of current deviation preset based on the rated parameters of the motor, which is used as a basic reference for distortion risk determination. It can be expressed as a percentage of the rated current of the motor or as a fixed value, and no specific limitation is made here. The environmental compensation value is a correction amount for adjusting the reference deviation threshold according to the environmental temperature, and it has a negative correlation with the environmental temperature and is used to adapt to different operating conditions.

[0110] Optionally, set the reference deviation threshold to 10% of the rated current of the motor. At the same time, the environmental temperature is measured in real time by a temperature sensor installed in the air-conditioning system. Then, according to a predefined temperature-compensation mapping table (for example, the initial compensation value is 0, and for every 1°C increase in the environmental temperature compared to the reference temperature of 25°C, the compensation value decreases by 0.5%, and vice versa, for every 1°C decrease, the compensation value increases by 0.5%), the environmental compensation value corresponding to the current environmental temperature is queried.

[0111] S2032. Determine the target deviation threshold according to the environmental compensation value and the reference deviation threshold.

[0112] Optionally, the target deviation threshold is the sum of the environmental compensation value and the reference deviation threshold. Or, the target deviation threshold is the weighted sum value of the environmental compensation value and the reference deviation threshold.

[0113] In the above S2031 - S2032, by combining the environmental compensation value and the reference deviation threshold to calculate the target deviation threshold, it realizes the dynamic adaptation to the change of the environmental temperature and improves the accuracy and robustness of distortion detection under different working conditions.

[0114] S204. Determine the risk score of the target detection period according to the total number of risk points of the distortion risk points within the target detection period.

[0115] Among them, the total number of risk points refers to the number of sampling points marked as distortion risk points within the target detection period. The risk score is a value calculated based on the total number of risk points.

[0116] Optionally, first initialize a counter to record the risk point contribution. Traverse the current deviation of each sampling point within the target detection period. If the current deviation of any sampling point exceeds the target deviation threshold, trigger the counter to increment by 1. Secondly, count the total number of risk points with excessive current deviation within the target detection period. If the total number of risk points exceeds n (for example, n = 8), additionally trigger the counter to increment by 3 to reflect the high density of distortion. Finally, take all the counts as the risk score for the target detection period.

[0117] Optionally, different weight coefficients can also be applied to the risk point counting of the compressor motor and the fan motor. For example, the weight of the compressor channel is 1.2, and the weight of the fan channel is 1.0. This is because the compressor motor is the core component of the air conditioning system, and its distortion has a greater impact on the system. Moreover, the failure of the core component may lead to more serious consequences. Therefore, using weighted priorities can optimize the risk assessment.

[0118] S205. Determine the current distortion state of the motor in the target detection period according to the risk score and the mapping relationship between the score distortion state.

[0119] Optionally, the mapping relationship between the score distortion state is stored in the memory in the form of risk levels, defined as:

[0120] If the risk score < 5, the current distortion state is "normal state";

[0121] If the risk score ≥ 5 and < 10, the current distortion state is "Level 1" (mild distortion);

[0122] If the risk score ≥ 10 and < 15, the current distortion state is "Level 2" (moderate distortion);

[0123] If the risk score ≥ 15, the current distortion state is "Level 3" (severe distortion).

[0124] We can obtain the risk score for the target detection period (for example, 12) and determine the corresponding current distortion state (for example, Level 2 (moderate distortion)) by looking up the mapping table. It can be understood that in the embodiments of the present application, the same mapping relationship between the score distortion state or different mapping relationships between the score distortion state can be adopted for the compressor motor and the fan motor, which is not specifically limited herein.

[0125] In S203 - S205 above, by comparing point - by - point deviations, determining the risk score, and mapping the relationship between the score and the distortion state, the current distortion state of the motor is determined, achieving rapid classification of the degree of motor distortion, and significantly improving the real - time performance of detection and the decision - making efficiency.

[0126] Furthermore, after determining the current distortion state of the motor, corresponding actions can be performed according to the current distortion state. For example, when the current distortion state is "Level 1" (mild distortion), only log records are made. When the current distortion state is "Level 2" (moderate distortion), motor power is limited, for example, limited to 80%. When the current distortion state is "Level 3" (severe distortion), gradient frequency reduction is triggered.

[0127] In some embodiments of the present application, after determining the current distortion state of the motor according to the current deviation, it further includes: if the current distortion state triggers a frequency reduction action, the motor is frequency - reduced through a frequency retraction algorithm. Among them, the frequency retraction algorithm includes:

[0128]

[0129] In the above formula, f new is the frequency after the motor is frequency - reduced; f current is the current operating frequency of the motor; Δf is the frequency adjustment step; Counter is the risk score; C threshold is the score threshold for triggering the frequency reduction action, for example, corresponding to 15 above; a is a preset coefficient, for example, a = 2.

[0130] The frequency retraction algorithm of the above - mentioned embodiment dynamically adjusts the frequency according to the difference between the risk score (Counter) and the threshold (C threshold ), the preset frequency adjustment step, and the preset coefficient, achieving precise frequency reduction matching the severity of distortion, ensuring a stable and controllable frequency reduction process, and avoiding mechanical vibration or system instability caused by frequency mutation.

[0131] Optionally, when performing the motor frequency - reduction operation, the frequency - reduction rate can also be limited, for example, the maximum change rate does not exceed 4Hz / s, to prevent torque mutation. In this way, by limiting the rotational speed change rate, mechanical vibration caused by rapid frequency adjustment is reduced, thereby reducing the temperature fluctuation perceived by the user and ensuring the running stability of the air - conditioning system and the comfort of the user experience.

[0132] Optionally, to maintain the optimal energy efficiency of the air - conditioning system, during the frequency - reduction process, the frequency operation range with the largest energy efficiency ratio is preferentially selected. If the frequency needs to be further reduced to below this range, the rotational speed of the fan motor is synchronously adjusted to balance the overall system efficiency. In this way, by preferentially maintaining a high energy efficiency ratio and combining coordinated speed control of the fan, the stability of the system energy efficiency under the frequency - reduction operation is ensured, and energy waste is reduced.

[0133] Optionally, after the frequency reduction operation is completed, the system continuously monitors the current distortion status in the subsequent n (e.g., 30) detection cycles. If the distortion count returns to zero, indicating that the distortion risk has been eliminated, the system gradually returns to the original operating frequency at a certain rate. If the severe distortion status is triggered multiple times (e.g., three times) within a certain period (e.g., within 24 hours), the system is permanently locked to the safe mode, and the fault code is reported to the monitoring system through the interface. This self-recovery mechanism realizes automatic frequency withdrawal through periodic monitoring, avoids the sharp increase in noise caused by long-term low-frequency operation, and improves the long-term operation safety of the system through the fault locking mechanism.

[0134] The motor current distortion detection method provided in the second embodiment of the present application significantly improves the accuracy, real-time performance, and system reliability of the current distortion detection of the compressor motor and the fan motor in the air-conditioning system through a series of optimization steps, and solves the problems of high delay in the traditional harmonic analysis method and high misjudgment rate of multi-motor coupling interference. Among them, by synchronously sampling the first and second sampling currents of the compressor and fan motors (S2011), and using independent first and second phase-locked loops to generate highly synchronous first and second reference currents (S2012 - S2013), dual-channel decoupled analysis is realized, effectively reducing the false alarm frequency caused by electromagnetic resonance in the low-frequency band and enhancing the ability to distinguish interharmonic interference. Using a second-order adaptive phase-locked loop (S2012a - S2012d) and a CORDIC orthogonal signal generator (S2013a - S2013d), combined with speed feedforward compensation and dynamic amplitude correction, accurate reference currents are generated, providing a high-quality benchmark for subsequent deviation calculation. By calculating the current deviation point by point (S202) and the target deviation threshold adaptively based on the ambient temperature (S2031 - S2032), accurate identification of the distortion risk points is realized, adapting to different working conditions and improving the detection robustness. Based on the total number of risk points and weighted counting to calculate the risk score (S204), and quickly determining the distortion status through hierarchical mapping (S205), significantly improving the detection real-time performance and decision-making efficiency. When the frequency reduction action is triggered, the frequency withdrawal algorithm, combined with the maximum frequency reduction rate limit and the energy efficiency ratio priority strategy, ensures smooth frequency reduction and stable system energy efficiency, reduces mechanical vibration and temperature fluctuations, and improves the user experience. The self-recovery mechanism avoids the sharp increase in noise during long-term low-frequency operation through multiple cycle monitoring and recovery rate, and the safety mode locking after multiple severe distortion triggers further guarantees the long-term safety of the system.

[0135] To facilitate better implementation of the motor current distortion detection method of the present application, the present application also provides a motor current distortion detection device based on the above motor current distortion detection method. The meanings of the nouns are the same as those in the above motor current distortion detection method, and the specific implementation details can refer to the description in the method embodiment.

[0136] Please refer toFigure 3 , Figure 3 is a schematic structural diagram of a current distortion detection device for a motor provided by an embodiment of the present application, and specifically may include:

[0137] A generation module 301, configured to obtain a real-time sampled current of the motor and generate a corresponding real-time reference current according to the real-time sampled current;

[0138] A deviation calculation module 302, configured to calculate a current deviation between a first sampling point of the real-time sampled current and a second sampling point of the real-time reference current at the same sampling moment within each detection period;

[0139] A distortion detection module 303, configured to determine a current distortion state of the motor according to the current deviation.

[0140] In some embodiments of the present application, the real-time sampled current includes a first sampled current of a compressor motor and a second sampled current of a fan motor sampled synchronously, and the real-time reference current includes a first reference current corresponding to the first sampled current and a second reference current corresponding to the second sampled current. Generating a corresponding real-time reference current according to the real-time sampled current includes: generating a first reference current corresponding to the first sampled current through a first phase-locked loop; generating a second reference current corresponding to the second sampled current through a second phase-locked loop.

[0141] In some embodiments of the present application, the first phase-locked loop includes a second-order adaptive phase-locked loop. Generating a first reference current corresponding to the first sampled current through the first phase-locked loop includes: obtaining a first real-time speed of the compressor motor; based on the first real-time speed and the first sampled current, iteratively generating a first phase of the first reference current through the second-order adaptive phase-locked loop; wherein the second-order adaptive phase-locked loop includes a phase discriminator term and a speed feedforward compensation term; determining a first amplitude of the first reference current at the first real-time speed according to a speed-amplitude mapping table; generating a first reference current synchronized with the first sampled current based on the first phase and the first amplitude.

[0142] In some embodiments of the present application, the second phase-locked loop includes an orthogonal signal generator based on a coordinate rotation digital calculation algorithm. Generating a second reference current corresponding to the second sampled current through the second phase-locked loop includes: obtaining a second real-time speed of the fan motor; using the orthogonal signal generator to dynamically adjust the phase-locked speed according to the second real-time speed and the frequency characteristics of the second sampled current, and iteratively generating a second phase of the second reference current; determining a second amplitude of the second reference current at the second real-time speed according to a speed-amplitude mapping table; generating a second reference current synchronized with the second sampled current based on the second phase and the second amplitude.

[0143] In some embodiments of the present application, determining the current distortion state of the motor according to the current deviation includes: if the current deviation of the target sampling point is greater than the target deviation threshold, taking the target sampling point as a distortion risk point; wherein, the target sampling point is any sampling point within the target detection period, and the target detection period is any detection period of the motor; determining the risk score of the target detection period according to the total number of risk points of the distortion risk points within the target detection period; and determining the current distortion state of the motor in the target detection period according to the risk score and the score distortion state mapping relationship.

[0144] In some embodiments of the present application, the method for determining the target deviation threshold includes: obtaining a preset reference deviation threshold and an environmental compensation value; wherein, the environmental compensation value has a negative correlation with the environmental temperature; and determining the target deviation threshold according to the environmental compensation value and the reference deviation threshold.

[0145] In some embodiments of the present application, after determining the current distortion state of the motor according to the current deviation, it further includes: if the current distortion state triggers a frequency reduction action, performing frequency reduction on the motor through a frequency withdrawal algorithm; wherein, the frequency withdrawal algorithm includes:

[0146]

[0147] In the above formula, f new is the frequency after the motor frequency reduction; f current is the current operating frequency of the motor; Δf is the frequency adjustment step; Counter is the risk score; C threshold is the score threshold for triggering the frequency reduction action; a is a preset coefficient.

[0148] In addition, the present application also provides an air conditioner, as Figure 4 shown, which shows a schematic structural diagram of the air conditioner involved in the present application. Specifically:

[0149] The air conditioner may include a processor 401 with one or more processing cores, a memory 402 with one or more computer-readable storage media, a power supply 403, an input unit 404 and other components. Those skilled in the art can understand that Figure 4 the air conditioner structure shown in

[0150] The processor 401 is the control center of the air conditioner, connecting various parts of the entire air conditioner through various interfaces and circuits. By running or executing software programs and / or modules stored in the memory 402, and by invoking the data stored in the memory 402, it performs various functions of the air conditioner and processes data, thereby monitoring the air conditioner as a whole. Optionally, the processor 401 may include one or more processing cores; preferably, the processor 401 may integrate an application processor and a modem processor. Among them, the application processor mainly processes the operating system, user interface, application programs, etc., and the modem processor mainly processes wireless communication. It can be understood that the above-mentioned modem processor may not be integrated into the processor 401 either.

[0151] The memory 402 can be used to store software programs and modules. The processor 401 executes various functional applications and data processing by running the software programs and modules stored in the memory 402. The memory 402 may mainly include a program storage area and a data storage area. Among them, the program storage area can store the operating system, application programs required for at least one function, etc.; the data storage area can store data created according to the use of the air conditioner, etc. In addition, the memory 402 may include high-speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other volatile solid-state storage devices. Correspondingly, the memory 402 may also include a memory controller to provide the processor 401 with access to the memory 402.

[0152] The air conditioner further includes a power supply 403 for supplying power to each component. Preferably, the power supply 403 can be logically connected to the processor 401 through a power management system, so as to realize functions such as management of charging, discharging, and power consumption management through the power management system. The power supply 403 may also include any components such as one or more DC or AC power supplies, a recharge system, a power device debugging circuit, a power converter or inverter, and a power status indicator.

[0153] The air conditioner may further include an input unit 404, which can be used to receive input digital or character information, and generate keyboard, mouse, joystick, optical or trackball signal inputs related to user settings and function controls.

[0154] Although not shown, the air conditioner may further include a display unit and the like, which will not be elaborated herein. Specifically, in this embodiment, the processor 401 in the air conditioner will, according to the following instructions, load the executable files corresponding to the processes of one or more application programs into the memory 402, and the processor 401 will run the application programs stored in the memory 402, so as to implement the steps in any of the motor current distortion detection methods provided by the embodiments of the present application: obtaining the real-time sampled current of the motor and generating a corresponding real-time reference current according to the real-time sampled current; calculating the current deviation between the first sampling point of the real-time sampled current and the second sampling point of the real-time reference current at the same sampling moment within each detection period; and determining the current distortion state of the motor according to the current deviation.

[0155] In the above embodiment, by obtaining the real-time sampled current and generating the real-time reference current, calculating the point-by-point deviation between the real-time sampled current and the reference current within each detection period, and determining the current distortion state according to the deviation. This method analyzes the point-by-point deviation in real time within the detection period, replaces the complete electrical cycle required for traditional harmonic analysis, and only needs a short period of time within the detection period to complete the distortion determination, significantly reducing the detection delay.

[0156] For the specific implementation of each of the above operations, reference may be made to the previous embodiments, which will not be elaborated herein.

[0157] Those of ordinary skill in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructions, or by controlling relevant hardware through instructions. The instructions can be stored in a computer-readable storage medium and loaded and executed by a processor.

[0158] Therefore, the present application provides a computer-readable storage medium, on which a computer program is stored. The computer program can be loaded by a processor to execute the steps in any of the motor current distortion detection methods provided by the present application.

[0159] For the specific implementation of each of the above operations, reference may be made to the previous embodiments, which will not be elaborated herein.

[0160] Among them, the computer-readable storage medium may include: read-only memory (ROM, Read Only Memory), random access memory (RAM, Random Access Memory), magnetic disk or optical disc, etc.

[0161] Since the instructions stored in the computer-readable storage medium can execute the steps in any of the motor current distortion detection methods provided by the present application, the beneficial effects that can be achieved by any of the motor current distortion detection methods provided by the present application can be realized. For details, refer to the previous embodiments, which will not be elaborated herein.

[0162] The above has introduced in detail a method, device, air conditioner, and computer-readable storage medium for detecting current distortion of a motor provided by the present application. Specific examples are used in this article to elaborate on the principles and implementation manners of the present invention. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present invention; at the same time, for those skilled in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A method for detecting current distortion of an electric motor, characterized in that, The method includes: Obtaining the real-time sampled current of the motor, and generating a corresponding real-time reference current according to the real-time sampled current; Calculating the current deviation between a first sampling point of the real-time sampled current and a second sampling point of the real-time reference current at the same sampling moment within each detection period; Determining the current distortion state of the motor according to the current deviation.

2. The method for detecting current distortion of the motor according to claim 1, wherein The real-time sampled current includes a first sampled current of the compressor motor and a second sampled current of the fan motor sampled synchronously, and the real-time reference current includes a first reference current corresponding to the first sampled current and a second reference current corresponding to the second sampled current. Generating a corresponding real-time reference current according to the real-time sampled current includes: Generating a first reference current corresponding to the first sampled current through a first phase-locked loop; Generating a second reference current corresponding to the second sampled current through a second phase-locked loop.

3. The method for detecting current distortion of the motor according to claim 2, characterized in that, The first phase-locked loop includes a second-order adaptive phase-locked loop. Generating a first reference current corresponding to the first sampled current through the first phase-locked loop includes: Obtaining a first real-time speed of the compressor motor; Based on the first real-time speed and the first sampled current, iteratively generating a first phase of the first reference current through the second-order adaptive phase-locked loop; wherein the second-order adaptive phase-locked loop includes a phase detector term and a speed feedforward compensation term; Determining a first amplitude of the first reference current at the first real-time speed according to a speed-amplitude mapping table; Generating a first reference current synchronized with the first sampled current based on the first phase and the first amplitude.

4. The method for detecting current distortion of the motor according to claim 2, characterized in that, The second phase-locked loop includes an orthogonal signal generator based on a coordinate rotation digital calculation algorithm. Generating a second reference current corresponding to the second sampled current through the second phase-locked loop includes: Obtaining a second real-time speed of the fan motor; Using the orthogonal signal generator, dynamically adjusting the phase-locking rate according to the second real-time speed and the frequency characteristics of the second sampled current, and iteratively generating a second phase of the second reference current; Determining a second amplitude of the second reference current at the second real-time speed according to a speed-amplitude mapping table; Generating a second reference current synchronized with the second sampled current based on the second phase and the second amplitude.

5. The method for detecting current distortion of the motor according to claim 1, characterized in that, Determining the current distortion state of the motor according to the current deviation includes: If the current deviation at a target sampling point is greater than a target deviation threshold, then taking the target sampling point as a distortion risk point; wherein, the target sampling point is any sampling point within a target detection period, and the target detection period is any detection period of the motor; Determining a risk score of the target detection period according to the total number of risk points of the distortion risk points within the target detection period; Determining the current distortion state of the motor in the target detection period according to the risk score and the score-distortion state mapping relationship.

6. The method for detecting current distortion of the motor according to claim 5, characterized in that, The determination method of the target deviation threshold includes: Obtaining a preset reference deviation threshold and an environmental compensation value; wherein, the environmental compensation value has a negative correlation with the environmental temperature; Determining the target deviation threshold according to the environmental compensation value and the reference deviation threshold.

7. The method for detecting current distortion of the motor according to claim 5, characterized in that, After determining the current distortion state of the motor according to the current deviation, the following steps are further included: If the current distortion state triggers a frequency reduction operation, the frequency of the motor is reduced by a frequency withdrawal algorithm; wherein, the frequency withdrawal algorithm includes: In the above formula, f new is the frequency after the frequency of the motor is reduced; f current is the current operating frequency of the motor; Δf is the frequency adjustment step; Counter is the risk score; C threshold is the score threshold for triggering the frequency reduction action; a is a preset coefficient.

8. An apparatus for detecting current distortion of an electric machine, characterized in that, The current distortion detection device of the motor includes: A generation module, configured to obtain the real-time sampled current of the motor and generate a corresponding real-time reference current according to the real-time sampled current; A deviation calculation module, configured to calculate the current deviation between the first sampling point of the real-time sampled current and the second sampling point of the real-time reference current at the same sampling moment in each detection period; A distortion detection module, configured to determine the current distortion state of the motor according to the current deviation.

9. A computer-readable storage medium, characterized in that, Stores a computer program, which when executed by a processor causes the processor to execute the steps of the method according to any one of claims 1 to 7.

10. An air conditioner, characterized in that, Includes a memory and a processor, the memory stores a computer program, which when executed by the processor causes the processor to execute the steps of the method according to any one of claims 1 to 7.

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