Method for controlling mechanical and electrical equipment of building intelligent system integration

Abstract

The application provides a kind of building intelligent system integrated electromechanical equipment control method, it is related to electromechanical equipment control technical field, the present application is based on the harmonic characteristic of electromechanical equipment under the same voltage, the harmonic characteristic table of each electromechanical equipment under different control frequency corresponding harmonic characteristic, based on the harmonic characteristic of each electromechanical equipment, and then analyze its appearance rate, harmonic elimination rate, hazard coefficient, determine the matching priority of each harmonic characteristic, based on the harmonic characteristic table of each electromechanical equipment, obtain the control sensitivity of the electromechanical equipment, and combine the operation stability, and then determine its control post level, based on the control post level of each electromechanical equipment, the matching priority of harmonic characteristic forms matching sequence code, carries out matching and eliminates the harmonic characteristic of harmonic, and judges whether electromechanical equipment needs to be controlled, for the electromechanical equipment needing to be controlled, after adjusting control frequency, carry out secondary matching and eliminate harmonic characteristic.

Description

Technical Field

[0001] This invention relates to the field of building electromechanical equipment control technology, specifically to a method for controlling electromechanical equipment in an integrated intelligent building system. Background Technology

[0002] Over the past few decades, the operation and control of electromechanical equipment such as HVAC, elevators, pumps, and lighting in building intelligent systems have been closely related to the power system. With the widespread use of nonlinear load equipment within buildings, the problem of power grid harmonic pollution has become increasingly prominent. Harmonics not only cause equipment overheating and shorten insulation life, but can also lead to malfunctions in protection devices and increased errors in metering instruments, seriously affecting the power supply quality of building power systems and the operational stability of electromechanical equipment. Existing building intelligent systems focus primarily on energy consumption optimization and fault diagnosis for the control of electromechanical equipment, lacking a systematic analysis of the harmonic characteristics generated by the equipment itself, and failing to incorporate harmonic management into the equipment collaborative control framework. Traditional harmonic mitigation methods rely on installing passive or active filters on the distribution side, which are costly, inflexible, and unable to dynamically adjust according to the real-time operating conditions of the equipment. How to achieve self-sensing, self-matching, and self-elimination of harmonic characteristics at the equipment level and organically integrate this with the operation and control of electromechanical equipment is a pressing technical challenge in the field of integrated control of building intelligent systems.

[0003] On the other hand, different electromechanical devices generate harmonic characteristics that vary during operation, with their amplitude, frequency, and phase dynamically changing with power supply voltage fluctuations and frequency adjustments. Existing equipment control methods fail to fully exploit the vector superposition relationship between the harmonic characteristics of different devices and lack a priority matching mechanism based on harmonic elimination potential. Furthermore, the operational stability and control sensitivity of different electromechanical devices vary significantly. If the control capabilities and operational reliability of the devices themselves are not considered during harmonic matching, some critical devices may experience shortened lifespans due to frequent adjustments or reduced harmonic elimination effectiveness due to response lag. Therefore, there is an urgent need to establish an intelligent method that deeply integrates harmonic characteristic analysis with equipment control strategies to achieve system-level coordinated harmonic suppression while ensuring the safe and stable operation of equipment.

[0004] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a method for controlling electromechanical equipment in an integrated intelligent building system, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for controlling electromechanical equipment in an integrated building intelligent system, comprising the following steps: Step 1: Synchronously acquire historical current timing data and control frequency timing data of the electromechanical equipment to be controlled under the same voltage. Based on timing alignment, obtain the current timing data of each electromechanical equipment under different control frequencies and extract harmonic features. Construct a harmonic feature table of each electromechanical equipment under different control frequencies. Step 2: Based on the correspondence between electromechanical equipment and harmonic features in the harmonic feature table, analyze the manifestation rate of each harmonic feature corresponding to the electromechanical equipment, determine the harmonic elimination rate of each harmonic feature by vector superposition with other harmonic features, and calculate the hazard coefficient of each harmonic feature based on its impact on voltage and current. Based on the manifestation rate, harmonic elimination rate and hazard coefficient, determine the matching priority of each harmonic feature corresponding to the electromechanical equipment. Step 3: Obtain the usage time distribution of electromechanical equipment to determine operational stability. Based on the harmonic characteristics of each electromechanical device in the harmonic characteristic table at different control frequencies, obtain the control sensitivity of the electromechanical equipment. Based on the control sensitivity and operational stability, determine the control post-stage of the electromechanical equipment. Step 4: Based on the control post-stage of each electromechanical device, form a matching sequence code with the matching priority of the harmonic features corresponding to each electromechanical device in the harmonic feature table, obtain the currently running electromechanical devices, and match the harmonic features of each electromechanical device according to the matching sequence code to meet the harmonic features for harmonic elimination; Step 5: Analyze the matching results to determine whether the electromechanical equipment needs to be controlled. For electromechanical equipment that needs to be controlled, perform secondary matching after adjusting the control frequency to eliminate harmonic characteristics.

[0007] Furthermore, the harmonic characteristics include harmonic amplitude, harmonic frequency, and harmonic phase; The method for extracting harmonic features is as follows: Discrete sampling sequences are obtained based on historical current time series data, and complex spectrum sequences are obtained through fast Fourier transform. The amplitude and phase of each type of harmonic are extracted from the complex spectrum sequences, with the phase referenced to the zero-crossing point of the fundamental voltage. The harmonic characteristic table is described as follows: Electromechanical equipment - frequency control - harmonic amplitude - harmonic frequency - harmonic phase.

[0008] Furthermore, the manifestation rate is the proportion of the number of harmonic features that are the same as the harmonic features of each electromechanical device in the total number of harmonic features corresponding to that electromechanical device, which is constructed in a harmonic feature table corresponding to each electromechanical device at different control frequencies.

[0009] Furthermore, the method for determining the harmonic cancellation rate is as follows: Based on the harmonic characteristic table corresponding to the harmonic characteristics of each electromechanical device under different control frequencies, a harmonic characteristic corresponding to the electromechanical device is selected. This harmonic characteristic is vector-superimposed with the harmonic characteristics corresponding to other electromechanical devices. The average amplitude of the superimposed harmonic characteristics is used as the elimination degree. An elimination threshold is set. Harmonic characteristics with elimination degrees less than the elimination threshold are determined to meet the harmonic elimination criteria. The two harmonic characteristics that meet the harmonic elimination criteria are called matching pairs. The ratio of the number of matching pairs of a harmonic characteristic to the number of all harmonic characteristics in the harmonic characteristic table under the same voltage is the harmonic elimination rate of that harmonic characteristic.

[0010] Furthermore, the steps for determining the matching priority of each harmonic feature are as follows: Calculate the hazard factor: The voltage harmonic distortion rate is calculated based on each harmonic voltage and voltage, and the current harmonic distortion rate is calculated based on each harmonic current and current. Based on the voltage harmonic distortion rate and voltage harmonic distortion rate, the hazard factor of the harmonic characteristic is calculated by assigning weights. Determine matching priority: The matching priority of each harmonic feature is determined by using an exponential function in the form of a product of the hazard coefficient, manifestation rate, and harmonic elimination rate. The calculation formula is as follows: in, To match the optimal coefficients, For visibility, Harmonic cancellation rate, The hazard coefficient; The matching priority coefficients of each harmonic feature are sorted in descending order, and an integer number is assigned to each harmonic feature in ascending order as the matching priority.

[0011] Furthermore, the usage time distribution of the electromechanical equipment includes the number of runs and the duration of each run; The method for judging operational stability is as follows: Based on the duration and number of times the electromechanical equipment operates, the mean and variance of the operating duration of the computer equipment are calculated. An adjustment coefficient is added to the variance, and the operating stability is obtained by dividing the mean of the operating duration by the sum of the variance and the adjustment coefficient.

[0012] Furthermore, the step of determining the control post-stage for each device is as follows: Obtain the control sensitivity of the electromechanical equipment: Based on the harmonic characteristic table of each electromechanical device under different control frequencies, the number of control frequencies of the electromechanical devices in the harmonic characteristic table and the number of harmonic characteristics corresponding to each control frequency of the electromechanical devices are counted. Based on the number of harmonic characteristics corresponding to each control frequency, the total number of harmonic characteristics of the electromechanical devices is calculated. The total number of harmonic characteristics is divided by the number of control frequencies to obtain the control sensitivity. Determine the control post-stage for each device: For the operational stability and control sensitivity of each electromechanical device, the weights are assigned and summed using the weighting method. Based on the summation result, the electromechanical devices are sorted in ascending order, and each device is assigned an integer sequence number according to the sorting order, which serves as the control post-stage for that device.

[0013] Furthermore, the method for forming the matching sequence code is as follows: The high-order bits of the matching sequence code are used as the control post-stage of each electromechanical device. The number of bits of the high-order bits is determined based on the number of bits of the maximum sequence number of the control post-stage. The low-order bits of the matching sequence code are used as the matching priority of the current harmonic type under the electromechanical device. The number of bits of the matching priority is determined based on the number of bits of the maximum sequence number of the matching priority. The two are combined to form a matching sequence code, and a unique matching sequence code is generated for each harmonic type of each device.

[0014] Furthermore, the specific steps for determining whether the electromechanical equipment needs to be adjusted are as follows: Determine the matching rate of electromechanical equipment under the previous power conditions: Under the same voltage, the ratio of the number of harmonic features that meet the harmonic elimination criteria matched according to the harmonic features corresponding to each electromechanical device to the number of harmonic features corresponding to that electromechanical device is used as the harmonic feature matching rate. By setting a matching threshold, electromechanical equipment that exceeds the matching threshold is determined to require regulation.

[0015] Furthermore, the step of eliminating harmonic characteristics by adjusting the control frequency and then performing secondary matching on the electromechanical equipment that needs to be controlled is as follows: Set the range of control frequency for the electromechanical equipment that needs to be controlled; According to the order of the control post-stage of the electromechanical equipment, a control frequency is selected sequentially within the control frequency range of each electromechanical equipment in descending order of its serial number as a pre-control scheme. Based on the harmonic characteristic table, the harmonic characteristics corresponding to the selected control frequency of each electromechanical equipment are found. The harmonic characteristics corresponding to the selected control frequency of each electromechanical equipment are vector-superimposed to obtain a superimposed comprehensive harmonic characteristic. The harmonic distortion rate of the voltage and current of this comprehensive harmonic characteristic is calculated. The harmonic elimination coefficient is obtained by summing the harmonic distortion rates of voltage and current. The pre-control scheme with the smallest harmonic elimination coefficient is selected as the control frequency of each electromechanical equipment for control.

[0016] Compared with the prior art, the beneficial effects of the present invention are: This invention is based on the harmonic characteristics of electromechanical equipment at the same voltage. It provides a harmonic characteristic table for each piece of equipment at different control frequencies. Based on the harmonic characteristics of each piece of equipment, it analyzes its manifestation rate, harmonic elimination rate, and hazard coefficient to determine the matching priority of each harmonic characteristic. Based on the harmonic characteristic table of each piece of equipment, it obtains the control sensitivity of that equipment and, combined with operational stability, determines its control post-stage. Based on the control post-stage of each piece of equipment and the matching priority of the harmonic characteristics, a matching sequence code is formed. Matching is performed to ensure the harmonic characteristics meet the requirements for harmonic elimination, and it is determined whether the equipment needs to be controlled. For equipment requiring control, a secondary matching process is performed after adjusting the control frequency to eliminate the harmonic characteristics.

[0017] This invention constructs a harmonic characteristic table for each electromechanical device at different control frequencies, and calculates the matching priority of each harmonic characteristic based on its manifestation rate, harmonic elimination rate, and hazard coefficient. This allows for the accurate identification of the types of harmonic characteristics with the greatest elimination potential and hazard level, thus prioritizing the treatment of harmonic components that have a significant impact on the power grid. Simultaneously, this invention introduces dual indicators of equipment operating stability and control sensitivity to determine the control post-stage of the equipment. Equipment with stable operation and fast control response is assigned a lower post-stage to prioritize participation in harmonic characteristic matching, while the control of electromechanical devices with large operating fluctuations or insensitive control responses is appropriately delayed. This avoids the impact of blind adjustment on the electromechanical devices, ensuring the long-term reliable operation of all electromechanical equipment within the building.

[0018] Based on this, the present invention encodes the control post-stage and matching priority into a matching sequence code. Using the matching sequence code as an index, the harmonic characteristics of each electromechanical device under the current operating condition are matched in a standardized manner, achieving standardization and traceability management of the harmonic elimination process. For electromechanical devices whose initial matching effect fails to meet the standard, the present invention further performs a secondary matching by traversing the harmonic characteristics within its adjustable frequency range and calculating the harmonic elimination coefficients under different pre-control schemes. The frequency setting that minimizes the overall harmonic distortion rate is selected as the final control command. This method transforms harmonic management from passive compensation to active prevention, achieving on-site harmonic reduction by dynamically adjusting the equipment operating frequency, significantly reducing the dependence on additional filtering devices and reducing harmonic losses in building power systems.

[0019] In summary, this invention organically integrates electromechanical equipment control with power harmonic management. Through a closed-loop process of harmonic characteristic quantification, matching priority generation, post-control level sorting, and secondary optimization control, it effectively suppresses the harmonic interaction effects within the building's intelligent system while ensuring equipment operational stability. This improves power supply quality, reduces equipment failure risks and maintenance costs, and provides an innovative technical path for the health management of power systems in green buildings and smart buildings. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall method flow of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0022] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0023] Example: Please see Figure 1 The present invention provides a technical solution: A method for controlling electromechanical equipment in an integrated building intelligent system, comprising the following steps: Step 1: Synchronously acquire historical current timing data and control frequency timing data of the electromechanical equipment to be controlled under the same voltage. Based on timing alignment, obtain the current timing data of each electromechanical equipment under different control frequencies and extract harmonic features. Construct a harmonic feature table of each electromechanical equipment under different control frequencies.

[0024] In this embodiment, the harmonic characteristics include harmonic amplitude, harmonic frequency, and harmonic phase.

[0025] The historical current timing data and control frequency timing data of the electromechanical equipment under the same voltage are acquired synchronously. This is because for the same electromechanical equipment, when the power supply voltage is at different levels, the operating point of its internal nonlinear components will shift, resulting in significant differences in the amplitude and phase of the generated harmonics. If harmonic data under different voltage conditions are recorded indiscriminately, the subsequently constructed harmonic characteristic table will lose its ability to accurately describe the harmonic emission characteristics of the equipment due to the ambiguity of the operating conditions, thus causing systematic deviations in matching priority calculation, secondary control frequency selection, and other aspects. Therefore, it is essential to ensure that the harmonic characteristics are the true responses under the same voltage background, thereby giving the harmonic characteristic table operating condition sensitivity and data consistency.

[0026] When synchronously acquiring historical current timing data and control frequency timing data of the electromechanical equipment under the same voltage, a multi-channel synchronous sampling module is deployed in the central control unit or edge data acquisition gateway of the building intelligent system. This module generates a unified time stamp pulse through a high-precision real-time clock chip, and uses this time stamp pulse to simultaneously trigger the analog signal sampling channel of the current transformer on each electromechanical equipment circuit and the digital acquisition channel of the control frequency read from the communication interface of the equipment frequency converter or programmable logic controller. This ensures that each current sampling point is strictly bound to the control frequency value at the corresponding moment through the same time stamp. In the data storage stage, the instantaneous waveform of the three-phase current effective value and the control frequency command value of each electromechanical equipment are continuously recorded, and the effective value of the three-phase voltage at the same common connection point is synchronously acquired to calibrate the voltage condition in real time, forming a current timing sequence, a control frequency timing sequence, and a voltage timing sequence with millisecond-level time stamps. When it is necessary to extract the voltage under a specific voltage condition... When analyzing historical data, the process first retrieves all time segments in the voltage time series where the effective voltage value is continuously stable within ±2% of the target voltage value. Based on the beginning and end timestamp boundaries of these time segments, subsequences specific to that voltage condition are extracted from both the current time series and the control frequency time series, ensuring that the extracted current and control frequency data occur under the same voltage background. Then, using the time nodes where the control frequency changes as the segmentation basis, current subsequences corresponding to consecutive control frequencies under the same voltage condition are grouped into a single data block. Each data block corresponds to a current time series sample of the device operating stably at a certain control frequency under that voltage condition. This completes the synchronous acquisition of current and control frequency data under the same voltage condition based on time-series alignment, providing a data foundation with precise time-dimensional alignment and a clean, consistent voltage condition for subsequent fast Fourier transform extraction of harmonic features from the current samples corresponding to each control frequency.

[0027] The method for extracting harmonic features is as follows: Discrete sampling sequences are obtained based on historical current time series data, and complex spectrum sequences are obtained through fast Fourier transform. The amplitude and phase of each type of harmonic are extracted from the complex spectrum sequences, with the phase referenced to the zero-crossing point of the fundamental voltage. The harmonic characteristic table is described as follows: Electromechanical equipment - frequency control - harmonic amplitude - harmonic frequency - harmonic phase.

[0028] The method for extracting harmonic features first requires discrete sampling of the current signal from the electromechanical equipment during operation. Since the harmonics generated by the electromechanical equipment in buildings are mainly concentrated in the low-frequency range, the highest harmonic order is typically considered to be 50th, or 2500 Hz. According to the Nyquist sampling theorem, the sampling frequency should be greater than twice the highest frequency component of the signal. Furthermore, to facilitate Fast Fourier Transform calculations, the sampling frequency is usually set to an integer power of 2 of the fundamental frequency of 50 Hz, for example, a sampling frequency of 6400 Hz, meaning 128 points are sampled per fundamental cycle. Using this sampling frequency, the analog signal output from the current transformer is sampled at equal intervals, continuously acquiring 10 fundamental cycles, totaling 1280 discrete data points, forming a sampling sequence, denoted as . ,in The integer index is between 0 and 1279.

[0029] During the sampling process, the power supply voltage signal is simultaneously acquired to determine the zero-crossing position of the fundamental voltage. Specifically, after low-pass filtering the voltage sampling sequence to remove high-frequency noise, linear interpolation is used to accurately locate the moment when the voltage waveform crosses the zero level from negative to positive. This moment is taken as the phase reference zero point for the entire analysis time window. At this time, the first sampling point in the current sampling sequence after the zero-crossing point is assigned the phase reference starting position. After obtaining the discrete current sampling sequence, a fast Fourier transform is performed to convert the time-domain sequence... Conversion to the complex spectrum sequence in the frequency domain ,in Integer indices from 0 to 1279, each All are complex numbers containing real and imaginary parts, corresponding to frequencies of... Multiply by the fundamental frequency, i.e., k multiplied by 50 Hz, to obtain the spectral component. Due to the symmetry property of the Fourier transform, actual physical harmonic components only exist in... The first half, from 0 to 640, where the DC component corresponds to Equal to 0, the fundamental component corresponds to Equal to 1, the second harmonic corresponds to The value equals 2, and so on up to the 50th harmonic. Equals 50. For any kth harmonic component, its amplitude is... Through complex numbers The magnitude is obtained by dividing the number of sampling points and multiplying by an appropriate amplitude recovery factor, i.e. Equal to 2 times The absolute value divided by 1280, while for the DC component If it equals zero, take it directly. The absolute value divided by 1280 does not need to be multiplied by two, and its phase Then through complex numbers The arctangent function is obtained, i.e. equals arctan(Imag( Divide by Real( In this calculation, Imag represents the imaginary part and Real represents the real part. The result is expressed in radians and can be converted to degrees as needed. Since the phase output by the Fast Fourier Transform (FFT) is relative to the first point of the sampling sequence with time zero, and this invention requires the fundamental voltage zero-crossing point as a unified reference, the extracted phase value needs to be corrected. Specifically, during sampling, the time interval Δt between the fundamental voltage zero-crossing point and the first sampling point of the current sampling sequence is recorded. If Δt is positive, it indicates that the zero-crossing point occurs Δt before the first sampling point. Therefore, for the kth harmonic, the phase value needs to be corrected in the original calculation. On top of this, a phase lead is superimposed, and this lead is equal to two. Multiply Multiplying by the fundamental frequency and then by Δt compensates for the phase lag or lead caused by the offset of the sampling start point. The corrected phase value is the absolute phase of each harmonic with the zero-crossing point of the fundamental voltage as a reference, thus ensuring that the harmonic phases extracted by different devices at different times are comparable and additive.

[0030] For example, if a piece of electromechanical equipment operates with a power supply voltage of 220V and a control frequency set to 45Hz, the current signal, after being extracted by Fast Fourier Transform, yields a first harmonic component with an amplitude of 1.1 mA, a frequency of 250Hz, and a corrected phase of 10.9 degrees with reference to the zero-crossing point of the fundamental voltage. The complete description of this harmonic characteristic in the harmonic characteristic table would be "220V-45Hz-1.1mA-250Hz-10.9°". The second harmonic component extracted from the same sampling analysis has an amplitude of 0.6 mA, a frequency of 350Hz, and a corrected phase of -19.2 degrees; its corresponding harmonic characteristic table record is "220V-45Hz-0.6mA-350Hz--19.2°". If the air conditioner adjusts its frequency to 50 Hz due to load changes under the same 220V voltage conditions, its current harmonic characteristics will change. Assuming the amplitude of the first harmonic component increases to 1.8 mA and the phase changes to 15.3 degrees, and the amplitude of the second harmonic component is 0.9 mA and the phase changes to -11.5 degrees, then two new records will be added to the table: "220V-50Hz-1.8mA-250Hz-15.3°" and "220V-50Hz-0.9mA-350Hz--11.5°". By recording each harmonic of all electromechanical equipment in the building under different voltage and control frequency combinations in the above format, the harmonic characteristic table forms a complete knowledge base covering multiple operating conditions, multiple frequencies, and multiple harmonic orders. When the central control unit executes step 4, it can quickly filter all harmonic entries that the air conditioner compressor should pay attention to, including 250 Hz 1.1 mA 10.9 kJ, 350 Hz 0.6 mA -19.2 kJ, etc., based on the current measured power supply voltage value of 220 volts and the equipment operating frequency of 45 Hz, and generate the corresponding matching sequence code accordingly. When performing secondary matching optimization in step 5, it can traverse frequency points such as 43 Hz, 45 Hz, and 48 Hz within the allowable control frequency range of the equipment, calculate the harmonic elimination coefficient under each candidate frequency by querying the harmonic characteristic combination of the corresponding prefix in the table, and thus select the optimal control frequency for execution.

[0031] In the field of building intelligent system integration and control, existing technologies for understanding the harmonic characteristics of electromechanical equipment are mostly at the qualitative assessment level. They lack both correlation mapping with specific power operating conditions and the ability to integrate scattered equipment harmonic data into a structured knowledge base. This step obtains discrete sampling sequences of the control frequency and current signals of electromechanical equipment under the same voltage, extracts the amplitude, frequency, and phase of harmonics using Fast Fourier Transform, and uses the fundamental voltage zero-crossing point as a unified phase benchmark. Finally, a harmonic feature table is constructed with "electromechanical equipment - control frequency - harmonic amplitude - harmonic frequency - harmonic phase" as the descriptive dimensions. The advantage of this method is that it transforms the multi-dimensional nonlinear relationship between control variables and harmonic responses under the same voltage into a searchable and comparable tabular knowledge representation. This imbues the originally isolated and disordered harmonic data with operating condition context semantics, providing a unified data foundation for subsequent quantitative analysis.

[0032] Existing harmonic analysis typically focuses only on fixed harmonic emission levels under rated operating conditions. This method, however, covers power conditions with varying voltage fluctuations, accurately reflecting the impact of grid voltage changes on the harmonic generation characteristics of the equipment, thus avoiding misjudgments of harmonic characteristics due to neglecting differences in operating conditions. The unified phase extraction method, using the fundamental voltage zero-crossing point as a reference, ensures the comparability and additivity of harmonic phase data from different devices, providing an accurate computational basis for the vector superposition of harmonic characteristics and the determination of elimination rates in subsequent steps.

[0033] Step 2: Based on the correspondence between electromechanical equipment and harmonic features in the harmonic feature table, analyze the manifestation rate of each harmonic feature corresponding to the electromechanical equipment. For each harmonic feature, determine the harmonic elimination rate by vector superposition with other harmonic features. Calculate the hazard coefficient of each harmonic feature based on its impact on voltage and current. Determine the matching priority of each harmonic feature corresponding to the electromechanical equipment based on the manifestation rate, harmonic elimination rate, and hazard coefficient.

[0034] In this embodiment, the manifestation rate is the proportion of the number of harmonic features that are the same as the harmonic features of each electromechanical device in the total number of harmonic features corresponding to that electromechanical device, which is constructed in a harmonic feature table corresponding to each electromechanical device at different control frequencies.

[0035] The fundamental purpose of calculating the manifestation rate using this method is to characterize the prevalence of specific harmonic types in the operational history of a particular device from a probabilistic statistical perspective. In building intelligent systems, the harmonic emissions of electromechanical equipment are not constant. For example, the same inverter air conditioner compressor, under a power supply voltage of 220 volts, may produce relatively obvious first and second harmonic characteristics when the control frequency is set to 45 Hz. However, when the control frequency is adjusted to 50 Hz, the first harmonic characteristic may remain stable, while the second harmonic may form a third harmonic characteristic due to the shift in the operating point. If the importance of the harmonic type is judged only by a single measurement, misjudgment will occur due to the interference of random operating conditions. It may include occasional harmonic characteristics that only appear at rare frequency points in the priority matching queue, or ignore the normal harmonic characteristics that exist continuously in most operating scenarios. By statistically analyzing the occurrence frequency of harmonic components of the same type and frequency under the same voltage in the harmonic characteristic table of the electromechanical equipment, and dividing this frequency by the total number of harmonic characteristic records for that equipment, the occurrence rate continuously ranges from zero to one. This objectively reflects the stability of the harmonic characteristic type accompanying equipment operation. The closer the occurrence rate is to one, the more frequently the harmonic characteristic appears regardless of frequency changes, indicating it is a characteristic harmonic emission of the equipment and should be a key focus for matching and elimination. Conversely, a lower occurrence rate indicates that the harmonic characteristic is only occasionally triggered at certain specific frequency settings, resulting in relatively low cost-effectiveness of treatment and allowing it to be placed lower in the matching priority ranking. The direct benefit of this calculation method is that it achieves vertical statistical abstraction of equipment harmonic behavior, aggregating discrete harmonic characteristic records scattered under different voltage conditions and frequency combinations into statistical features based on harmonic characteristic type. This provides a probabilistic basis for subsequent priority ranking at the individual equipment level, rather than relying solely on the instantaneous value of a single sample.

[0036] Taking the variable frequency air conditioner compressor as an example, the following records are included in the harmonic characteristic table for this electromechanical equipment: One fifth harmonic feature and one seventh harmonic feature were extracted under the conditions of power supply voltage of 220 volts and control frequency of 45 Hz. One fifth harmonic feature and one ninth harmonic feature were extracted under the conditions of power supply voltage of 220 volts and control frequency of 50 Hz.

[0037] The air conditioner compressor has a total of 2 records in the harmonic characteristic table for the fifth harmonic characteristic under 2 operating conditions, 1 record for the ninth harmonic characteristic, and 1 record for the seventh harmonic characteristic, for a total of 4 harmonic characteristics. Therefore, the manifestation rate of the fifth harmonic characteristic is 2 (the number of fifth harmonic characteristics in this electromechanical equipment) divided by the total number of harmonic characteristics (4), which equals 0.5. Based on the above calculation, the fifth harmonic characteristic has the highest probability of occurrence under all operating conditions of this air conditioner compressor, and is considered a characteristic harmonic emission of this equipment. In the subsequent step two, when determining the matching priority, its manifestation rate dimension score is the highest, and under similar conditions, it will be assigned a higher priority matching order.

[0038] In this embodiment, the method for determining the harmonic cancellation rate is as follows: Based on the harmonic characteristic table corresponding to the harmonic characteristics of each electromechanical device under different control frequencies, a harmonic characteristic corresponding to the electromechanical device is selected. This harmonic characteristic is vector-superimposed with the harmonic characteristics corresponding to other electromechanical devices. The average amplitude of the superimposed harmonic characteristics is used as the elimination degree. An elimination threshold is set. Harmonic characteristics with elimination degrees less than the elimination threshold are determined to meet the harmonic elimination criteria. The two harmonic characteristics that meet the harmonic elimination criteria are called matching pairs. The ratio of the number of matching pairs of a harmonic characteristic to the number of all harmonic characteristics in the harmonic characteristic table under the same voltage is the harmonic elimination rate of that harmonic characteristic.

[0039] The fundamental technical logic of the harmonic characteristic matching method lies in utilizing the inconsistency of the natural phase distribution of harmonics from multiple devices within a building to quantify the potential ability of a specific harmonic type to be passively canceled by harmonics from other devices at the system level. In intelligent building systems, when harmonic currents of the same frequency generated by numerous frequency converters and rectifier loads converge on a common bus, they are not simply added arithmetically. Instead, they are synthesized as complex vectors according to their respective amplitudes and phase angles relative to a unified phase reference. If the phase difference between two harmonics of the same frequency is close to 180 degrees, the synthesized amplitude will be significantly smaller than the sum of their individual amplitudes, or even lower than the amplitude of a single harmonic. This is the physical basis for the natural cancellation of harmonics.

[0040] This step involves iterating through all harmonic features generated by other devices and performing complex addition operations on each harmonic feature to obtain the combined harmonic amplitude after each superposition. Then, the arithmetic mean of the amplitudes obtained from all superposition operations is calculated as the elimination degree. The smaller the elimination degree value, the weaker the amplitude increase caused by phase mismatch when the harmonic type is injected into the power grid together with other harmonics, and the more significant the natural attenuation effect.

[0041] The elimination threshold can be set by referring to the proportion of the average amplitude of all harmonic features. Specifically, the elimination threshold is determined by multiplying the arithmetic mean of the amplitudes of all harmonic features participating in the same-frequency superposition by a fixed proportional coefficient. This method directly uses the statistical center of actual harmonic data as a reference, without needing to consider the rated current of the equipment. It is simple to calculate and can adapt to the amplitude levels of different harmonic types. When the combined amplitude after superposition is lower than this threshold, it indicates that the cancellation effect has significantly reduced the harmonic amplitude below the group average, and it can be determined that harmonic elimination is achieved.

[0042] For a given harmonic characteristic, the harmonic cancellation rate is calculated as the ratio of the number of matching pairs for that harmonic characteristic to the total number of harmonic characteristics in the harmonic characteristic table under the same voltage. A higher ratio indicates a stronger tendency for that harmonic type to be naturally neutralized within the existing harmonic characteristic distribution pattern of the operating electromechanical equipment group. Therefore, it should be given higher weight in the matching priority ranking to fully utilize existing passive cancellation conditions. The significant advantage of this calculation method is that it transforms the traditional qualitative understanding of "harmonic cancellation probability" into a quantifiable and rankable numerical indicator. This allows the central control unit to prioritize harmonic types that achieve good harmonic cancellation effects without significant adjustments to equipment operating parameters when determining matching sequence codes, thereby achieving system-level harmonic suppression while minimizing disturbances to normal equipment operation.

[0043] Specifically, the operation steps for superimposing this harmonic feature with other harmonic features are as follows: For example, the selected target harmonic feature is... Its amplitude is , frequency is The phase with reference to the zero-crossing point of the fundamental voltage is Filter from the harmonic characteristic table all harmonics with the same frequency as the target harmonic, i.e., frequencies equal to... Other equipment harmonic characteristics constitute a set ,in From one to each Has amplitude and phase For each Performing complex addition converts the amplitude and phase into rectangular coordinates, i.e. The corresponding complex number is represented as Multiply Plus Multiply Multiply , The corresponding complex number is represented as Multiply Plus Multiply Multiply The sum of the two results in a complex number, the magnitude of which is the combined harmonic amplitude after this superposition. Where j is the imaginary unit. The elimination degree is calculated by... Summing and dividing by N yields the average amplitude, which is the elimination degree equal to... .

[0044] In this embodiment, the steps for determining the matching priority of each harmonic feature are as follows: Calculate the hazard factor: The voltage harmonic distortion rate is calculated based on each harmonic voltage and voltage, and the current harmonic distortion rate is calculated based on each harmonic current and current. Based on the voltage harmonic distortion rate and voltage harmonic distortion rate, the hazard factor of the harmonic characteristic is calculated by assigning weights.

[0045] The method of calculating voltage and current harmonic distortion rates separately, assigning weights, and then summing them to obtain the hazard coefficient is based on the fact that the harm of harmonics to the power grid cannot be fully characterized by a single dimension. In building power distribution systems, harmonic voltage distortion mainly affects voltage-sensitive equipment connected in parallel, such as precision instruments and control power modules. Excessively high voltage harmonic distortion rates may lead to equipment malfunctions or accelerated insulation aging. Harmonic current distortion mainly threatens conductors, transformer windings, and protection devices in series circuits, causing additional heating, neutral line overload, and circuit breaker tripping. If the degree of hazard is assessed solely based on harmonic current amplitude or a single distortion rate index, it will not be able to fully reflect the differentiated impact of harmonic components on different parts of the power grid.

[0046] This method calculates voltage harmonic distortion rate and current harmonic distortion rate separately and assigns weights reflecting the system's sensitivity characteristics. This allows the hazard coefficient to simultaneously consider the dual destructive effects of harmonics on both voltage waveforms and current RMS values, thus more accurately identifying the true urgency of addressing each harmonic characteristic in the matching priority ranking. The direct benefit of this calculation method is that the weight allocation can be flexibly adjusted according to the actual load composition of the building. If the building contains a large number of medical devices or data center equipment sensitive to voltage waveform distortion, the weight of the voltage harmonic distortion rate can be appropriately increased to prioritize the elimination of harmonic types that may interfere with their normal operation. If the power distribution line load rate is high and the transformer capacity margin is tight, the weight of the current harmonic distortion rate can be emphasized to reduce losses and overload risks.

[0047] The calculation process of voltage harmonic distortion rate is as follows: First, obtain the effective value of the fundamental voltage U1. For a specific harmonic order k, extract the amplitude U_k of the harmonic voltage from the harmonic characteristic table. Then, the single harmonic voltage content rate is the ratio of U_k to U1. The total voltage harmonic distortion rate THD_u is equal to the square root of the sum of the squares of the single content rates of all harmonic orders of interest. That is, THD_u is equal to the sum of the squares of (U_k divided by U1) from k equal to 2 to the highest order, multiplied by 100%.

[0048] The calculation process for current harmonic distortion rate is similar: obtain the effective value of the fundamental current I1 and the amplitude of each harmonic current I_k. The total current harmonic distortion rate THD_i is equal to the sum of the squares of (I_k divided by I1) from k equal to 2 to the highest order, multiplied by 100%.

[0049] Among them, the weight α of voltage harmonic distortion rate plus the weight β of current harmonic distortion rate equals 1. The specific weights can be set according to the actual sensitivity of the building's power distribution system through the analytic hierarchy process or operation and maintenance experience.

[0050] Determine matching priority: The matching priority of each harmonic feature is determined by multiplying the hazard factor, manifestation rate, and harmonic elimination rate using an exponential function. The calculation formula is as follows: in, To match the optimal coefficients, For visibility, Harmonic cancellation rate, The hazard coefficient; The matching priority coefficients of each harmonic feature are sorted in descending order, and an integer number is assigned to each harmonic feature in ascending order as the matching priority.

[0051] The matching priority coefficient is calculated using an exponential function: the cube root of the product of the hazard coefficient, manifestation rate, and harmonic elimination rate multiplied by 100. Integer numbers are then assigned based on these coefficients, ranked from largest to smallest. The core logic emphasizes the balance and non-compensable nature of the three-dimensional indicators. In the harmonic mitigation scenario of building intelligent systems, an ideal priority matching harmonic feature should simultaneously possess three characteristics: high manifestation rate (frequent occurrence in the operating history of the electromechanical equipment), high harmonic elimination rate (easily canceled naturally after superposition with harmonic vectors from other equipment), and high hazard coefficient (significant actual damage to the voltage and current quality of the power grid). If a linear weighted summation method is used to calculate the comprehensive score, a harmonic feature with an extremely low score in one dimension but extremely high scores in the other two dimensions may still achieve a high total score and be pushed to the top. For example, a harmonic manifestation rate of only 0.1, extremely uncommon, but with an elimination rate as high as 0.9 and a hazard coefficient as high as 0.8, might have a comprehensive score under linear weighting that exceeds that of a harmonic feature with approximately 0.5 in each of the three dimensions. However, in actual governance, even if a harmonic with an extremely low frequency of occurrence has great cancellation potential and is highly harmful, its long-term benefits after investing matching resources are limited due to its highly sporadic nature, and therefore it should not be given priority. The product form inherently has a weakest link amplification effect; a low value in any component will significantly lower the product result, thus ensuring that only harmonic characteristics performing well in all three dimensions can obtain a high matching coefficient, reflecting the principle of prudence in the allocation of harmonic governance resources. The use of cube root operation is to restore the dimensions of the product result to a scale close to the original index, facilitating the setting of a percentage display threshold. Multiplying by one hundred is merely a numerical scaling operation that maps the coefficient of excellence to the zero-to-one-hundred range, without affecting the ranking result. The advantage of this method is that it eliminates the need to manually set the weight coefficients for each dimension, avoiding subjective disputes over weight allocation. Simultaneously, the product operation's sensitivity to low scores automatically avoids harmonic types with significant weaknesses in any dimension of manifestation rate, elimination rate, or hazard coefficient, prioritizing the matching sequence for harmonic governance targets that truly deserve control efforts.

[0052] In building intelligent systems, there are numerous and diverse electromechanical devices, and the combinations of harmonic characteristics generated by these devices under the same voltage and control frequency vary greatly. If these harmonic characteristics are not prioritized and blindly matched for elimination, significant problems such as high computational complexity, slow convergence, and the neglect of important harmonics will arise. Existing harmonic mitigation technologies largely rely on the centralized installation of filters on the power distribution side, lacking quantitative evaluation methods for the individual harmonic emission characteristics of equipment. This makes it impossible to identify which harmonic types occur frequently and are highly harmful, or to predict which harmonics have natural vector cancellation potential. Consequently, mitigation measures are disconnected from the actual harmonic behavior of the equipment, and resource investment is disproportionate to the harmonic suppression effect. This invention addresses this technological blind spot by using the harmonic characteristic table constructed in step one as a data foundation. It quantifies and profiles each harmonic characteristic from three dimensions: First, it measures the frequency of occurrence of a certain type of harmonic under different operating conditions of the same equipment through the occurrence rate, reflecting its necessity as a routine management target. Second, it assesses the amplitude attenuation capability of this harmonic characteristic after being superimposed with harmonic characteristic vectors from other equipment through the harmonic elimination rate, exploring the potential space for utilizing the natural harmonic cancellation effect between equipment. Finally, it quantifies the impact of the harmonic component on the voltage and current waveform distortion of the power grid through the hazard coefficient, indicating its urgency for management. These three dimensions—universality, attenuability, and hazard—assign comparable numerical labels to harmonic characteristics. Finally, an exponential function in the form of a product integrates the three indicators into a unified matching priority coefficient and ranks them to generate a matching priority. This allows for the priority handling of harmonic types with high occurrence frequency, high cancellation potential, and significant harm to the power grid during coordinated harmonic elimination, focusing limited control resources and communication bandwidth on the most critical management targets.

[0053] This step elevates harmonic mitigation decisions from empirical qualitative judgments to multi-dimensional, data-driven quantitative assessments. Traditional methods often rely solely on whether harmonic amplitude exceeds limits, neglecting to consider whether the harmonic persists during equipment operation (manifestation rate) or whether adjusting the operating parameters of other equipment can achieve phase complementarity (elimination rate). This step, by defining and calculating indicators across these three dimensions, establishes for the first time a harmonic characteristic priority evaluation system for building electromechanical equipment clusters. This allows the matching process to follow an optimal order derived from a mathematical model, rather than relying on trial and error based on manual experience. Furthermore, the hazard coefficient calculation does not simply use harmonic amplitude or distortion rate as a single indicator, but simultaneously considers and weights the distortion effects of the harmonic on voltage and current, providing a comprehensive evaluation. This approach is suitable for both voltage-sensitive loads and current-sensitive protection devices, overcoming the limitations of existing standards where harmonic evaluation indicators tend to emphasize one aspect while neglecting the actual impact of another. Furthermore, the formula for determining the matching priority adopts a product form rather than a linear weighted summation. The underlying logic is that a low score in any dimension will significantly lower the overall priority, ensuring that only harmonic characteristics that are outstanding in terms of frequency of occurrence, offsetting potential, and degree of harm can obtain a higher matching ranking. This avoids the unreasonable situation where a poor score in one dimension is mistakenly pushed to the forefront due to high scores in other dimensions, reflecting the principle of prudent allocation of resources for harmonic governance.

[0054] Step 3: Obtain the usage time distribution of electromechanical equipment to determine operational stability. Based on the harmonic characteristics of each electromechanical device in the harmonic characteristic table at different control frequencies, obtain the control sensitivity of the electromechanical device. Based on the control sensitivity and operational stability, determine the control post-stage of the electromechanical device.

[0055] In this embodiment, the usage time distribution of the electromechanical equipment includes the number of runs and the duration of each run; The method for judging operational stability is as follows: Based on the duration and number of times the electromechanical equipment operates, the mean and variance of the operating duration of the computer equipment are calculated. An adjustment coefficient is added to the variance, and the operating stability is obtained by dividing the mean of the operating duration by the sum of the variance and the adjustment coefficient.

[0056] The duration of each run directly reflects the time span during which the electromechanical equipment maintains a stable operating state after a single start-up. A longer duration indicates that the equipment enters a relatively fixed electrical and mechanical operating condition once put into operation, and the harmonic emission characteristics remain stable accordingly. At this point, applying a frequency regulation command provides sufficient continuous operating time for the equipment to respond and verify the regulation effect, and it will not introduce additional transient harmonic impacts due to frequent start-ups and shutdowns. The average duration alone is insufficient to fully characterize stability; the number of runs is introduced to calculate the variance of the duration of each run. Variance reflects the dispersion of the duration of a single run: if the number of runs is high but the duration of each run is highly consistent, and the variance approaches zero, it indicates that the equipment's start-up and shutdown patterns are very strong, the operating state is predictable, and the risk of intervention by the frequency converter or controller at any time is low. Conversely, if the duration of each run varies significantly (large variance) due to load fluctuations or human intervention, it indicates frequent switching of equipment operating conditions and drastic changes in the phase and amplitude of harmonic emissions with the operating conditions. In this case, forcibly applying frequency regulation is highly likely to superimpose with the sudden changes in the equipment's own operating conditions, causing vibration, overcurrent, or malfunctioning protection.

[0057] Operational stability is calculated by dividing the mean of each run of electromechanical equipment by the sum of its variance and adjustment coefficient. The logic behind this method is to simultaneously capture two dimensions: the equipment's continuous operation capability and consistency. The mean represents the average duration of a single run, reflecting its typical ability to handle continuous loads. The variance measures the dispersion of each run's duration; a larger variance indicates stronger randomness in equipment start-up and shutdown and more drastic fluctuations in operating status, while a smaller variance indicates more stable operation. Using the mean as the numerator and the sum of the variance and adjustment coefficient as the denominator, equipment with concentrated and low-fluctuation run times achieves higher stability values. Conversely, even equipment with a large mean but also a large variance suffers from reduced stability due to denominator expansion, thus objectively reflecting the predictability of equipment operation. The direct advantage of this method is its simplicity; the evaluation can be completed simply by analyzing the duration data in the equipment's start-up and shutdown records, without the need for additional vibration or temperature sensors. It is easily implemented in batches using historical operation logs in the central control unit of a building intelligent system. The adjustment factor serves two purposes: first, it prevents mathematical overflow caused by a zero denominator when the variance is zero (i.e., the equipment's runtime is exactly the same each time), ensuring the calculation remains valid by using a positive decimal as the denominator's safety margin; second, it smooths the excessive amplification effect of variance differences on stability values. When the variance is small, the adjustment factor can suppress drastic fluctuations in stability values ​​caused by small fluctuations, making the ranking results more robust. The value of the adjustment factor can be determined based on the typical variance magnitude of the equipment's runtime, typically ranging from one-tenth to one-hundredth of the median variance of each equipment. For example, if the variance of most equipment's runtime is in the range of ten to one hundred square minutes, the adjustment factor can be set to one, which avoids an excessively small denominator without overly suppressing the discriminative function that variance should have.

[0058] In this embodiment, the step of determining the control post-stage for each device is as follows: Obtain the control sensitivity of the electromechanical equipment: Based on the harmonic characteristic table of each electromechanical device under different control frequencies, the number of control frequencies of the electromechanical devices in the harmonic characteristic table and the number of harmonic characteristics corresponding to each control frequency of the electromechanical devices are counted. Based on the number of harmonic characteristics corresponding to each control frequency, the total number of harmonic characteristics of the electromechanical devices is calculated. The total number of harmonic characteristics is divided by the number of control frequencies to obtain the control sensitivity. Determine the control post-stage for each device: For the operational stability and control sensitivity of each electromechanical device, the weights are assigned and summed using the weighting method. Based on the summation result, the electromechanical devices are sorted in ascending order, and each device is assigned an integer sequence number according to the sorting order, which serves as the control post-stage for that device.

[0059] The control sensitivity is calculated by dividing the number of harmonic characteristics corresponding to the electromechanical equipment under the same voltage by the number of control frequencies corresponding to the electromechanical equipment. The ratio obtained by dividing the two is the control sensitivity.

[0060] Its meaning lies in measuring the richness of harmonic characteristic changes induced by a unit frequency adjustment. In the harmonic characteristic table, under the same voltage, each selectable value of the frequency adjustment corresponds to a set of harmonic characteristic records. The more frequency ranges and the denser the harmonic characteristics at each range, the more significant the differences in harmonic combinations generated by the device at different operating frequencies, and the more diverse the harmonic alternatives the system can call upon by changing its frequency command. Higher adjustment sensitivity means that a larger range of harmonic phase and amplitude changes can be obtained by applying a small frequency adjustment to the device, thus providing more vector cancellation possibilities in the harmonic matching elimination process; conversely, low adjustment sensitivity indicates that no matter how the frequency is adjusted, the harmonic emission characteristics of the device change very little, and the marginal contribution of adjusting the device to system-level harmonic suppression is limited. The advantage of this method is that it relies entirely on the harmonic characteristic table constructed in step one, without the need for additional data collection or modeling. The calculation process only involves counting and simple division of the records in the table, resulting in high execution efficiency and the same source as the core data of harmonic matching, ensuring the consistency of the index with the data in the subsequent matching sequence code generation stage.

[0061] When determining the priority level for regulation, a method is used where operational stability and regulation sensitivity are weighted, summed, and sorted from smallest to largest, then assigned integer serial numbers. The purpose is to transform the comprehensive judgment of whether equipment is suitable for priority regulation into a comparable numerical ranking. Operational stability reflects whether the equipment can withstand frequent adjustments without deterioration in operating conditions, while regulation sensitivity reflects whether adjusting the equipment can bring about effective harmonic changes. These two aspects correspond to the safety and effectiveness of regulation, respectively. Only equipment that performs well in both aspects is suitable for placement at the forefront of the regulation sequence. The weighting is set based on building operation and maintenance experience. If the equipment in the building is generally old and has poor tolerance to regulation, the weight of operational stability can be appropriately increased; if harmonic problems are prominent and rapid relief through regulation is urgently needed, the weight of regulation sensitivity can be emphasized. When there is no clear preference, the two can be given equal weights, i.e., 0.5 each.

[0062] For example, an air conditioner compressor has 2 control frequencies, a total of 5 harmonic characteristics, and a control sensitivity equal to 5 divided by 2, which equals 2.5. An elevator inverter has only one control frequency, at which 4 harmonic characteristics are recorded, and its control sensitivity equals 4 divided by 1, which equals 4.0. A variable frequency water pump has 1 control frequency, at which 2 harmonic characteristics are recorded, and its control sensitivity equals 2 divided by 1, which equals 2.

[0063] Regarding operational stability, based on historical start-stop duration statistics for each device, the air conditioning compressor has a large variance in operating time due to frequent start-stop cycles caused by room temperature fluctuations, resulting in a stability score of 0.8; the elevator inverter has a highly regular operating time, resulting in a stability score of 1.5; the water pump operates intermittently but with relatively concentrated durations, resulting in a stability score of 1.2. Taking an operational stability weight of 0.5 and a control sensitivity weight of 0.5, the overall score for the air conditioning is 0.5 x 0.8 + 0.5 x 2.5 = 1.65; the overall score for the elevator is 0.5 x 1.5 + 0.5 x 4.0 = 2.75; and the overall score for the water pump is 0.5 x 1.2 + 0.5 x 2.0 = 1.60. Sort the sums from smallest to largest, the water pump (1.60) is the smallest, followed by the air conditioning (1.65), and the elevator (2.75) is the largest. Therefore, the control post-stage allocation is: water pump number 1, air conditioning number 2, and elevator number 3. The smaller the serial number, the higher the priority of regulation. Although the water pump has moderate regulation sensitivity, its operation stability is acceptable and its overall score is the lowest. Its harmonic characteristics will be pre-processed during harmonic matching. Although the elevator has the highest regulation sensitivity, it is extremely stable and important. Frequent adjustments may affect the quality of vertical transportation services. Therefore, it is given a higher post-level delayed regulation, which reflects a refined control strategy under the premise of ensuring the stable operation of core equipment.

[0064] In building intelligent systems, there are numerous types of electromechanical equipment with significantly different operating characteristics. Some equipment operates continuously and stably for extended periods, while others experience intermittent starts and stops or frequent speed changes due to load fluctuations. This imbalance in operating conditions directly determines the responsiveness and tolerance of each device to control commands. Current technologies for collaborative control of electromechanical equipment typically treat all devices as undifferentiated controlled objects. Once a control strategy is generated, commands are issued according to uniform rules, without considering the individual operational stability and adjustment response characteristics of the equipment. This approach presents two potential risks: First, for electromechanical equipment with poor operational stability, such as elevators with frequent starts and stops and large fluctuations in operating time, or water pumps with intermittent switching, applying frequency adjustment commands during unstable operation may exacerbate equipment fatigue, shorten service life, or even trigger protective shutdowns. Second, for electromechanical equipment with low control sensitivity, such as fixed-frequency equipment with a narrow adjustable frequency range or limited harmonic characteristic changes at different control frequencies, even frequent adjustments to its operating parameters may not yield significant harmonic reduction effects, instead increasing communication and control overhead. Therefore, before assigning harmonic matching elimination tasks to various electromechanical devices, it is necessary to quantitatively assess the suitability of the electromechanical devices for regulation and determine the regulation sequence accordingly to ensure the rationality and economy of the control actions.

[0065] This step extracts operational stability and control sensitivity indicators from two dimensions: equipment usage time distribution and control frequency range. These two indicators are then weighted and combined to determine the control post-stage. Its advantage lies in incorporating the equipment's physical constraints and operating status into the preliminary considerations of collaborative control decisions. Operational stability is judged based on the mean and variance of each operation duration of the electromechanical equipment. The mean reflects the typical duration of continuous operation, while the variance reflects the dispersion of the operation duration. After introducing an adjustment coefficient into the variance term, the mean divided by the sum of the variance and the adjustment coefficient is used as the stability measure. This allows equipment with concentrated operation durations and small fluctuations to obtain higher stability scores.

[0066] The sensitivity of the control is obtained directly from the harmonic characteristic table constructed in step 1. Under the same voltage, it is measured by the ratio of the number of selectable frequency ranges of the electromechanical equipment to the total number of harmonic characteristics at the corresponding frequency. The larger the ratio, the richer the harmonic characteristic changes caused by the frequency adjustment of the equipment, that is, the more sensitive the response to control commands. After weighting and sorting the two, integer serial numbers are assigned to each electromechanical equipment as control post-stages according to the summation result from smallest to largest. The smaller the post-stage value, the more suitable the equipment is to be preferentially controlled.

[0067] The beneficial effect of this method is that it transforms the originally ambiguous problem of prioritizing the control of electromechanical equipment into a computable ranking problem based on historical operating data and static parameters. This enables the scientific determination of the order of control participation when facing the task of multi-equipment coordinated harmonic suppression, rather than blindly mobilizing all equipment at the same time or randomly selecting equipment for adjustment.

[0068] The significant advancement of this step lies in the first-time quantification and embedding of operational reliability and controllability indicators of electromechanical equipment into the control decision-making process. Traditional building electromechanical equipment control systems either focus solely on energy consumption and comfort indicators or assess equipment health status in isolation during fault diagnosis, never considering the equipment's own operational adaptability as a pre-constraint for control strategy generation. This step effectively avoids the risk of applying adjustments to fluctuating electromechanical equipment at inappropriate times through operational stability indicators, and filters out low-sensitivity equipment with high adjustment costs and low harmonic improvement benefits through control sensitivity indicators, thereby improving the utilization efficiency of control resources while ensuring safe equipment operation. In the overall solution of this patent, the control post-stage output of this step directly serves as the high-order digit of the matching sequence code in step four. The high-order digit determines the macroscopic ranking position of all harmonic characteristics under the same electromechanical equipment in the matching sequence. The harmonic characteristics of smaller downstream devices are brought forward and prioritized for harmonic matching and elimination processes; while larger downstream electromechanical devices are appropriately delayed in their control. When control capacity is limited or response speed requirements are high, this prioritization mechanism ensures that control actions are first applied to those electromechanical devices that operate smoothly and are sensitive to adjustment, thus protecting sensitive electromechanical devices and maximizing the harmonic suppression benefit per unit of control action.

[0069] Step 4: Based on the control post-stage of each electromechanical device, form a matching sequence code with the matching priority of the harmonic features corresponding to each electromechanical device in the harmonic feature table, obtain the currently running electromechanical device, and match the harmonic features of each electromechanical device according to the matching sequence code to meet the harmonic features for harmonic elimination.

[0070] When matching the harmonic characteristics of each operating electromechanical device according to the matching sequence code to meet the harmonic elimination criteria, the harmonic characteristics of all online operating electromechanical devices in the current control cycle are first arranged in ascending order according to their corresponding matching sequence codes, forming a queue to be matched. The high-order digits of the matching sequence code represent the control post-stage, and the low-order digits represent the matching priority. Therefore, the harmonic characteristic at the front of the queue is the one with the smallest control post-stage sequence number, i.e., the electromechanical device most suitable for priority control, and the highest matching priority, i.e., the most valuable for treatment. Starting from the head of the queue, the target harmonic characteristic pointed to by the first matching sequence code is extracted and denoted as Hmb. Then, all harmonic characteristics with the same frequency as Hmb under the current power condition are traversed in the harmonic characteristic table to form a candidate matching set. For each harmonic characteristic Hpd in the candidate set, its amplitude and phase are extracted according to the matching sequence code, and then superimposed with Hmb in sequence to calculate the composite amplitude M. The synthesized amplitude M is compared with the preset elimination threshold T. If M is less than T, Hpd is determined to be a matched harmonic feature of Hmb that meets the requirements for harmonic elimination. The two form a pair of cancelable combinations. After matching is completed, starting from the head of the queue, the target harmonic feature pointed to by the second matching sequence code is retrieved. The method for setting the elimination threshold has been described in step 2.

[0071] At this point, the central control unit records the matching pair, marks Hmb as a successful match, and synchronously removes the matching sequence code entry corresponding to Hpd from the queue to be matched, so as to avoid the same harmonic feature being matched repeatedly.

[0072] If, after traversing the entire candidate matching set, the superposition amplitude M of all Hpd and Hmb is greater than or equal to the elimination threshold T, it indicates that there is no harmonic feature in the currently operating equipment group that can effectively cancel out Hmb. At this point, any adjustment action is performed on Hmb, and it is directly marked as a non-matching object and skipped. The next harmonic feature corresponding to the matching sequence code is then retrieved from the waiting-to-match queue, and the above candidate search and vector superposition determination process is repeated.

[0073] The queue traversal continues until the queue to be matched is empty or no matching object can be found for any of the remaining harmonic features. Skipped harmonic features retain their original state and will participate in sorting and matching again when the matching sequence code is regenerated in the next control cycle, or enter the secondary matching process in step five to adjust the control frequency before matching. This serial matching mechanism, which involves sequential code retrieval, candidate traversal, vector judgment, pairing and removal upon success, and skipping upon failure, ensures that harmonic features with low control post-stage and high matching priority have priority in obtaining the opportunity to cancel harmonics from other devices. At the same time, the design of removing entries from both sides after successful matching avoids the waste of control resources caused by the same harmonic feature being matched multiple times, enabling the efficient completion of as many harmonic pairing and elimination tasks as possible within a limited control cycle.

[0074] In this embodiment, the method for forming the matching sequence code is as follows: The high-order bits of the matching sequence code are used as the control post-stage of each electromechanical device. The number of bits of the high-order bits is determined based on the number of bits of the maximum sequence number of the control post-stage. The low-order bits of the matching sequence code are used as the matching priority of the current harmonic type under the electromechanical device. The number of bits of the matching priority is determined based on the number of bits of the maximum sequence number of the matching priority. The two are combined to form a matching sequence code, and a unique matching sequence code is generated for each harmonic type of each device.

[0075] Taking the matching sequence code AB as an example, when the matching sequence code AB is "12", the first digit "1" on the left occupies the high bit, corresponding to the first control post-level sequence number; the second digit "2" on the right occupies the low bit, corresponding to the second matching priority sequence number. Therefore, in the matching sequence code "12", the high bit is "1" and the low bit is "2".

[0076] For example, there are 3 electromechanical devices participating in harmonic matching. After calculation in step 3, the control post-stages are water pump number 1, air conditioner number 2, and elevator number 3. Therefore, the maximum number of the control post-stage is 3, and its number of bits only needs to be represented by 1 decimal digit. Therefore, the number of bits of the high-order digit is determined to be 1.

[0077] In step 2, the matching priority number of the fifth harmonic feature of the elevator is calculated to be 1, the matching priority number of the ninth harmonic feature of the water pump is 2, the matching priority number of the fifth harmonic feature of the air conditioner is 3, and the matching priority number of the seventh harmonic feature of the air conditioner is 9. Assuming that the maximum matching priority number of each harmonic type is 9, the number of bits of the lower digits only needs to be 1 decimal digit to cover it.

[0078] Based on this, a matching sequence code is generated for each harmonic type of each piece of electromechanical equipment. For example, the operating stage number of a water pump is 1, and the matching priority number of its ninth harmonic feature is 2. The high-order digit is 1, and the low-order digit is 2. The two are directly concatenated to form the matching sequence code "12". If the water pump also has a seventh harmonic feature and the matching priority number is 4, then the corresponding matching sequence code is "14".

[0079] If the number of electromechanical devices is large, causing the maximum sequence number of the control post-stage to reach 12, then the high-order digits need to be 2 bits. The sequence number 1 for the water pump post-stage should be represented as "01", the sequence number 2 for the air conditioner post-stage should be represented as "02", and the sequence number 12 for the elevator post-stage should be represented as "12". Correspondingly, the matching sequence code becomes 4 bits. For example, the ninth harmonic characteristic of the water pump is "0102", the fifth harmonic characteristic of the air conditioner is "0203", and the seventh harmonic characteristic of the elevator is "1201". Through the above coding rules, each harmonic characteristic of each device obtains a globally unique matching sequence code. Only by sorting the sequence code values ​​from smallest to largest can hierarchical scheduling be automatically achieved, first by the device control post-stage, and then by harmonic matching priority, without needing to calculate priority relationships online each time.

[0080] This step solidifies the control strategy into a pre-computable sequence code table through encoding, so that only table lookup and sequential matching operations are required during actual operation, eliminating the need for complex real-time priority arbitration. Specifically, the high-order bits of the control post-level determine the primary key for sorting. That is, whether the electromechanical equipment as a whole is suitable for participation in control determines the macroscopic position of all its subordinate harmonic features in the matching queue. All harmonic features of equipment with smaller post-levels are processed with priority over equipment with larger post-levels, reflecting a global respect for the stability of equipment operation and the sensitivity of control. The low-order bits of the matching priority determine the processing order of different harmonic features within the same equipment, ensuring that after selecting the control target equipment, the harmonic types with high manifestation rate, high elimination potential, and severe harm are matched first. The combination of high-order and low-order bits makes the matching sequence code naturally support hierarchical sorting, and can stably output the execution order that meets the design intent without additional weighting coefficients or sorting algorithms.

[0081] This step is responsible for integrating the scattered evaluation results generated in the preceding steps into a unified and executable control sequence. After the calculations in steps 2 and 3, each harmonic feature is assigned two independent ranking attributes: one is the matching priority, which characterizes the urgency of the harmonic type's own governance; the other is the control post-level, which characterizes the suitability of the electromechanical equipment to which the harmonic belongs. These two attributes describe the priority of control actions from the harmonic dimension and the equipment dimension, respectively. However, if the two act independently on the control decision, it will be difficult to form a consistent execution logic when facing complex scenarios with multiple devices and multiple harmonics. For example, contradictory instructions may arise, requiring priority control of high-priority harmonics of a higher-level equipment in a certain post-level, while low-priority harmonics of a lower-level equipment in another post-level are shelved.

[0082] This step constructs a mapping rule from two-dimensional priority to one-dimensional total order by combining the control post-level as the high-order digit and the matching priority as the low-order digit to form a matching sequence code. This ensures that each harmonic feature is assigned a globally unique sequence identifier with clear comparative significance. Harmonic matching can be automatically implemented by sequentially performing harmonic matching according to the sequence code in ascending order, thus achieving the coordinated implementation of the device-level and harmonic-level dual-layer priority strategy. This method reduces the multi-dimensional sorting problem to a one-dimensional sequence traversal problem, greatly simplifying the decision-making logic during real-time operation and avoiding the computational overhead and convergence uncertainty caused by online multi-objective optimization.

[0083] Step 5: Analyze the matching results to determine whether the electromechanical equipment needs to be controlled. For electromechanical equipment that needs to be controlled, perform secondary matching after adjusting the control frequency to eliminate harmonic characteristics.

[0084] Since the operating frequencies of each piece of electromechanical equipment are independently determined by load demand, environmental settings, or manual commands, and have not undergone collaborative optimization for system-level harmonic suppression, the initial matching results often fail to guarantee that each piece of equipment achieves ideal harmonic cancellation pairing. Some equipment may be marked as having no matching object and skipped because the harmonic characteristics corresponding to its current operating frequency do not match the harmonic phase distribution of other equipment. This results in the inability to find a cancellation target with a synthetic amplitude lower than the cancellation threshold after traversing the candidate set. If no further measures are taken for these devices, the harmonics they generate will continue to be injected into the grid, causing continuous deterioration of power quality. This step is specifically for this group of equipment that failed the initial matching, i.e., the electromechanical equipment that needs to be regulated. By actively adjusting their operating frequencies to change the harmonic emission characteristics, potential harmonic cancellation opportunities are explored through secondary matching, and the optimal regulation frequency is ultimately selected with the goal of minimizing the harmonic cancellation coefficient. This design adds a control means to actively adjust the equipment operating parameters to create cancellation conditions on the basis of passively utilizing the existing harmonic distribution for matching, forming a two-stage harmonic suppression strategy of "matching first, then optimizing".

[0085] The core advantage of this step lies in transforming the control frequency from a single functional setting variable into a control variable that also considers harmonic mitigation objectives. While ensuring the basic functions of the equipment are not affected, it fully utilizes the diversity of harmonic characteristics within the adjustable frequency range to achieve proactive harmonic reduction on-site. In practice, for each piece of electromechanical equipment with a matching rate below a preset threshold—that is, equipment requiring control—the search space is defined by all control frequency levels for that equipment at the same voltage in the harmonic characteristic table. Each candidate frequency is then assumed to be adjusted, and the corresponding harmonic characteristic combination is retrieved from the harmonic characteristic table. This combination is then vector-superimposed with the harmonic characteristics of the other equipment requiring control to obtain the synthesized harmonic characteristics under the candidate frequency scheme. Finally, the sum of the harmonic distortion rates of voltage and current is calculated, i.e., the harmonic elimination coefficient.

[0086] By traversing all candidate control frequencies, the control frequency setting that minimizes the harmonic elimination coefficient is selected as the control command and issued to the actuator. This method uses minimizing overall harmonic distortion as the optimization criterion, rather than pursuing the harmonic elimination rate of a single device in isolation, reflecting a systemic view of collaborative optimization. Compared with existing technologies, in current building electromechanical equipment control methods, frequency regulation only serves process objectives such as cooling capacity, flow rate, or speed, while harmonic mitigation relies entirely on independent filtering devices, making the two separate. This step integrates the two control objectives of frequency regulation and harmonic suppression within a unified optimization framework. Without increasing hardware filtering investment, the algorithm fully leverages the inherent harmonic emission regulation capabilities of the frequency converter, achieving system integration of harmonic mitigation functions in a software-defined manner, resulting in significant economic and flexibility advantages.

[0087] In this embodiment, the specific steps for determining whether the electromechanical equipment needs to be adjusted are as follows: Determine the matching rate of electromechanical equipment under the previous power conditions: Under the same voltage, the ratio of the number of harmonic features that meet the harmonic elimination criteria matched according to the harmonic features corresponding to each electromechanical device to the number of harmonic features corresponding to that electromechanical device is used as the harmonic feature matching rate. By setting a matching threshold, electromechanical equipment that exceeds the matching threshold is determined to require regulation.

[0088] The matching rate of electromechanical equipment is defined as the ratio of the number of harmonic features that the equipment actually matches and meets the harmonic cancellation conditions to the total number of its own harmonic features under the same voltage and control frequency. The core reason for using this calculation method is that the result of a single harmonic matching is determined independently for each harmonic feature. A particular electromechanical equipment may contain multiple harmonic features, some of which find matching pairs, while others fail to do so. If the success of matching all harmonic features is used as the trigger condition for secondary control, many devices with only a few mismatched harmonic features will be forced to adjust their frequencies, resulting in excessively frequent and potentially counterproductive control actions. Conversely, if no threshold is set, the mismatched harmonic features will remain unmanaged for a long time. As a normalized proportional indicator, the matching rate directly reflects the overall contribution of the electromechanical equipment to harmonic cancellation at its current operating frequency. A higher matching rate indicates that the current frequency selection of the electromechanical equipment is more conducive to system-level harmonic suppression, while a lower matching rate indicates a severe mismatch between the harmonic feature combination generated at the current frequency and the harmonic phase pattern of other electromechanical equipment, necessitating frequency adjustment for improvement.

[0089] Matching rate provides a continuous and comparable numerical scale, enabling the use of a unified secondary control triggering standard for different types and sizes of electromechanical equipment, avoiding the cumbersome process of setting absolute threshold values ​​for different equipment due to varying total harmonic characteristics.

[0090] The matching threshold can be determined based on the overall desired level of harmonic suppression effect combined with the adequacy of control resources. If power quality requirements are strict and control computing resources are sufficient, the matching threshold can be set to a higher value, such as 0.7 or 0.8, to encourage more equipment to participate in secondary frequency optimization. If it is desired to reduce the frequency of intervention in equipment operating frequencies to ensure process stability, the matching threshold can be appropriately lowered, such as to 0.5. When there is no clear bias, 0.6 is usually taken as the default threshold. Its physical meaning is that at least half of the harmonic characteristics of the equipment can find a cancellation pair under the current operating conditions; otherwise, secondary regulation is triggered.

[0091] In this embodiment, the step of eliminating harmonic characteristics by adjusting the control frequency and then performing secondary matching on the electromechanical equipment that needs to be controlled is as follows: For the electromechanical equipment requiring regulation, a range of regulation frequencies is set. Based on the order of the regulation post-stages of the electromechanical equipment, a regulation frequency is selected sequentially within the regulation frequency range of each electromechanical equipment in descending order of its serial number as a pre-regulation scheme. Based on the harmonic characteristic table, the harmonic characteristics corresponding to the selected regulation frequency of each electromechanical equipment are found. The harmonic characteristics corresponding to the selected regulation frequency of each electromechanical equipment are vector-superimposed to obtain a superimposed comprehensive harmonic characteristic. The harmonic distortion rate of the voltage and current of this comprehensive harmonic characteristic is calculated. The harmonic elimination coefficient is obtained by summing the harmonic distortion rates of voltage and current. The pre-regulation scheme with the smallest harmonic elimination coefficient is selected as the equipment regulation frequency for each electromechanical equipment to regulate it.

[0092] The fundamental principle behind using this method to regulate electromechanical equipment is to place the frequency adjustment decision of a single piece of equipment within the global evaluation framework of the overall harmonic suppression effect, rather than pursuing the improvement of the harmonic matching rate of the equipment itself in isolation. If one only seeks the frequency point within the frequency range that maximizes the harmonic matching rate of equipment that has not matched harmonic characteristics, although it can improve the matching statistics of that equipment, it may lead to an exacerbation of the overall distortion after synthesis because the harmonic phase generated at the new frequency tends to converge with the harmonic phase of other equipment, resulting in a situation of local optimization but global degradation.

[0093] By using the overall vector superposition of harmonic characteristics of all devices within the currently set control frequency range as the evaluation criterion, and calculating the total distortion rate of voltage and current of the superimposed harmonic characteristics as the harmonic elimination coefficient, this method ensures that every frequency control action aims to reduce the overall harmonic level of the building power grid, rather than being limited to the perspective of a single device. The advantage of this method is that it upgrades multi-electromechanical device collaborative harmonic suppression from passive matching to active optimization. Utilizing the diversity of harmonic emissions within the adjustable frequency range, it can search for the frequency combination that minimizes global harmonic distortion through a limited number of offline table lookups and complex number operations. This requires no additional hardware investment, has low algorithm complexity, and can be executed online in real time.

[0094] For example, consider the case where the initial matching rate of a variable frequency air conditioner compressor under a power supply voltage of 220V is only 0.33, which is lower than the threshold of 0.6, and it is determined to be an electromechanical device that needs to be adjusted.

[0095] In the stage of eliminating harmonic characteristics through secondary matching, the reason for adjusting the control according to the sequence number of the control post-stage from large to small (i.e., prioritizing the processing of devices with large sequence numbers that were originally placed later) is that devices with large sequence numbers in the control post-stage are usually placed at the end of the matching queue in the first matching due to poor operational stability or low control sensitivity.

[0096] At this point, adopting a reverse order from large to small in the secondary regulation essentially gives these "difficult to regulate and with few matching opportunities" devices a chance to prioritize reselecting regulation frequencies. First, a frequency is determined for them that can best integrate into the system's offsetting pattern. Then, smaller (easier to regulate and more stable) devices in the subsequent regulation stage are allowed to adapt to and match this optimized frequency environment. This "difficult first, easy later" traversal strategy can more efficiently approximate the frequency combination with the minimum global harmonic distortion of the system, avoiding a situation where subsequent devices have no suitable offsetting targets due to fixing the frequencies of sensitive devices first.

[0097] For example, there are two pieces of electromechanical equipment that need to be regulated: an air conditioning compressor with a regulating post-stage of 8, with a regulating frequency range including two levels: 45Hz and 50Hz, currently actually operating at 45Hz; and an elevator frequency inverter with a regulating post-stage of 7, operating at 38Hz.

[0098] First, calculate the pre-control scheme one, which maintains a constant 45Hz. In this case, the air conditioner generates 5 harmonic characteristics; the elevator generates 3 harmonic characteristics at 220V and 38Hz. The harmonics of all devices at the same frequency are vector-superimposed to obtain a superimposed harmonic characteristic. The harmonic distortion rate of this harmonic characteristic with respect to the power supply voltage and current is calculated, and then the harmonic elimination coefficient of pre-control scheme one is calculated. Then, the control frequency of the air conditioner is selected. Based on the number of harmonic characteristics corresponding to the air conditioner frequency of 50Hz in the harmonic characteristic table, the case of the air conditioner frequency of 50Hz and the elevator generating 3 harmonic characteristics at 220V and 38Hz is taken as pre-control scheme two. The harmonic elimination coefficient of pre-control scheme two is calculated and compared with the harmonic elimination coefficients of the two schemes. For example, the coefficient of scheme one is 8.32 and that of scheme two is 7.14. The harmonic elimination coefficient of scheme two is smaller, indicating that after adjusting the air conditioner frequency from 45Hz to 50Hz, the total global harmonic voltage and current distortion is lower and the overall power quality is better. Therefore, the central control unit selects 50Hz as the control frequency of the air conditioner compressor and issues the control order. As can be seen from the above process, this method takes minimizing the global harmonic distortion of the system as the sole optimization criterion, avoids the limitations of a single device perspective, makes full use of the law of harmonic characteristics of frequency converters changing with frequency, and achieves active optimization and control of the harmonic level of the building power distribution system without increasing hardware costs.

[0099] The method for setting the control frequency range can be combined with the specific process function requirements undertaken by the electromechanical equipment in the current building intelligent system, and the frequency control ratio can be set according to the frequency converter control accuracy of the electromechanical equipment, and the control frequency range can be set according to the current control frequency value and control ratio.

[0100] For example, for electromechanical equipment that is sensitive to frequency fluctuations, the current control frequency is set to ±1% to ±2%. Then, the current control frequency is multiplied by the control ratio to calculate the upward and downward floating values ​​respectively. That is, the difference between the control frequency and the control ratio multiplied by the downward floating ratio is used as the lower limit of the control frequency range, and the sum of the base control frequency and the control ratio multiplied by the upward floating ratio is used as the upper limit of the control frequency range, forming a continuous adjustable range centered on the current control frequency.

[0101] The method of combining equipment process requirements with inverter control accuracy, and setting the control frequency range by a small proportion centered on the current control frequency, has the advantage of achieving a fine balance between ensuring equipment process stability and system harmonic suppression capability during harmonic secondary matching. Specifically, using the current control frequency, rather than the nameplate reference frequency, as the center of the range ensures that the optimization search always revolves around the actual operating conditions of the equipment. This is because the real-time operating frequency of electromechanical equipment in building intelligent systems is often dynamically adjusted according to environmental load or process flow. If a wide range is mechanically set centered on a control frequency far from the current value, the optimal frequency selected by secondary matching will deviate too much from the current operating conditions. When the inverter receives a new frequency command, it needs to perform a large step response, which can easily cause increased equipment operating noise and instantaneous fluctuations in energy consumption. This strategy of setting the control range according to the importance of equipment process and the accuracy of inverter effectively avoids the hidden danger of sacrificing the operating quality of core equipment due to the excessive pursuit of minimizing the harmonic elimination coefficient in the traditional fixed wide-range search method, and truly achieves the synergistic unity of active harmonic control and reliable operation of building electromechanical systems.

[0102] The reason for using the direct summation of voltage harmonic distortion rate and current harmonic distortion rate as the harmonic elimination coefficient is that the harm of harmonics to building power distribution systems is exerted through two parallel physical paths: voltage distortion and current distortion, which are not interchangeable. Voltage harmonic distortion rate characterizes the degree to which harmonic voltage components distort the fundamental voltage waveform. It mainly affects voltage-sensitive equipment connected in parallel to the power grid, such as building automation controllers, sensor power modules, and LED driver circuits. Excessive voltage distortion may lead to increased sampling errors, false triggering of protection devices, or accelerated insulation aging in these devices. Current harmonic distortion rate characterizes the additional losses and thermal effects generated by harmonic current components on impedance. It mainly threatens conductors, transformer windings, neutral lines, and protective switches connected in series in the circuit. Higher current distortion results in more severe line heating, more significant transformer derating, and a greater risk of neutral line overload. If only voltage distortion rate or current distortion rate is used as the objective function for frequency optimization, a seesaw effect may occur, where optimization improves one indicator while worsening the other. For example, although the amplitude of the synthesized harmonics decreases at a certain candidate frequency, the change in phase distribution causes an increase in the harmonic voltage drop across the inductive reactance due to the harmonic current. This leads to an increase in voltage distortion rate and a decrease in current distortion rate. A single indicator cannot determine whether the frequency scheme is beneficial or detrimental to the overall system. Summing these two factors directly to construct the harmonic elimination coefficient essentially assigns equal weight to voltage quality and current quality management. This simple linear aggregation method forces the frequency selection process to consider both the voltage and current effects of harmonics, ensuring that the global benefits of the selected control frequency are multi-dimensional rather than unilaterally biased. The advantage of this method is its minimal computational cost. Only two divisions and one addition are needed after the vector superposition of each candidate frequency to obtain comparable evaluation indicators. It eliminates the need for complex multi-objective Pareto optimization algorithms or weight tuning processes, making it highly compatible with the limited computational resources of the central control unit of building intelligent systems. Furthermore, the summed coefficient has a clear physical meaning, allowing maintenance personnel to intuitively understand the changing trend of the current overall harmonic level.

[0103] All the above formulas use dimensionless numerical values ​​for calculation, and the numerical values ​​substituted into the formulas are all in the International System of Units (SI). The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0104] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented in software, the above embodiments can be implemented, in whole or in part, as a computer program product. Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution.

[0105] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0106] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A method for controlling electromechanical equipment in an integrated building intelligent system, characterized in that, The specific steps include: Step 1: Synchronously acquire historical current timing data and control frequency timing data of the electromechanical equipment to be controlled under the same voltage. Based on timing alignment, obtain the current timing data of each electromechanical equipment under different control frequencies and extract harmonic features. Construct a harmonic feature table of each electromechanical equipment under different control frequencies. Step 2: Based on the correspondence between electromechanical equipment and harmonic features in the harmonic feature table, analyze the manifestation rate of each harmonic feature corresponding to the electromechanical equipment, determine the harmonic elimination rate of each harmonic feature by vector superposition with other harmonic features, and calculate the hazard coefficient of each harmonic feature based on its impact on voltage and current. Based on the manifestation rate, harmonic elimination rate and hazard coefficient, determine the matching priority of each harmonic feature corresponding to the electromechanical equipment. Step 3: Obtain the usage time distribution of electromechanical equipment to determine operational stability. Based on the harmonic characteristics of each electromechanical device in the harmonic characteristic table at different control frequencies, obtain the control sensitivity of the electromechanical equipment. Based on the control sensitivity and operational stability, determine the control post-stage of the electromechanical equipment. Step 4: Based on the control post-stage of each electromechanical device, form a matching sequence code with the matching priority of the harmonic features corresponding to each electromechanical device in the harmonic feature table, obtain the currently running electromechanical devices, and match the harmonic features of each electromechanical device according to the matching sequence code to meet the harmonic features for harmonic elimination; Step 5: Analyze the matching results to determine whether the electromechanical equipment needs to be controlled. For electromechanical equipment that needs to be controlled, perform secondary matching after adjusting the control frequency to eliminate harmonic characteristics.

2. The electromechanical equipment control method for building intelligent system integration according to claim 1, characterized in that: The harmonic characteristics include harmonic amplitude, harmonic frequency, and harmonic phase. The method for extracting harmonic features is as follows: Discrete sampling sequences are obtained based on historical current time series data, and complex spectrum sequences are obtained through fast Fourier transform. The amplitude and phase of each type of harmonic are extracted from the complex spectrum sequences, with the phase referenced to the zero-crossing point of the fundamental voltage. The harmonic characteristic table is described as follows: Electromechanical equipment - frequency control - harmonic amplitude - harmonic frequency - harmonic phase.

3. The electromechanical equipment control method for building intelligent system integration according to claim 1, characterized in that: The manifestation rate is the proportion of the number of harmonic features that are the same as the harmonic features of each electromechanical device in the total number of harmonic features corresponding to that electromechanical device, which is constructed in a harmonic feature table corresponding to each electromechanical device at different control frequencies.

4. The electromechanical equipment control method for building intelligent system integration according to claim 1, characterized in that: The method for determining the harmonic cancellation rate is as follows: Based on the harmonic characteristic table corresponding to the harmonic characteristics of each electromechanical device under different control frequencies, a harmonic characteristic corresponding to the electromechanical device is selected. This harmonic characteristic is vector-superimposed with the harmonic characteristics corresponding to other electromechanical devices. The average amplitude of the superimposed harmonic characteristics is used as the elimination degree. An elimination threshold is set. Harmonic characteristics with elimination degrees less than the elimination threshold are determined to meet the harmonic elimination criteria. The two harmonic characteristics that meet the harmonic elimination criteria are called matching pairs. The ratio of the number of matching pairs of a harmonic characteristic to the number of all harmonic characteristics in the harmonic characteristic table under the same voltage is the harmonic elimination rate of that harmonic characteristic.

5. The electromechanical equipment control method for building intelligent system integration according to claim 1, characterized in that: The steps for determining the matching priority of each harmonic feature are as follows: Calculate the hazard factor: The voltage harmonic distortion rate is calculated based on each harmonic voltage and voltage, and the current harmonic distortion rate is calculated based on each harmonic current and current. Based on the voltage harmonic distortion rate and voltage harmonic distortion rate, the hazard factor of the harmonic characteristic is calculated by assigning weights. Determine matching priority: The matching priority of each harmonic feature is determined by multiplying the hazard factor, manifestation rate, and harmonic elimination rate using an exponential function. The calculation formula is as follows: in, To match the optimal coefficients, For visibility, Harmonic cancellation rate, The hazard coefficient; The matching priority coefficients of each harmonic feature are sorted in descending order, and an integer number is assigned to each harmonic feature in ascending order as the matching priority.

6. The electromechanical equipment control method for building intelligent system integration according to claim 1, characterized in that: The usage time distribution of the electromechanical equipment includes the number of runs and the duration of each run; The method for judging operational stability is as follows: Based on the duration and number of times the electromechanical equipment operates, the mean and variance of the operating duration of the computer equipment are calculated. An adjustment coefficient is added to the variance, and the operating stability is obtained by dividing the mean of the operating duration by the sum of the variance and the adjustment coefficient.

7. The electromechanical equipment control method for building intelligent system integration according to claim 1, characterized in that: The steps for determining the control post-stage of each device are as follows: Obtain the control sensitivity of the electromechanical equipment: Based on the harmonic characteristic table of each electromechanical device under different control frequencies, the number of control frequencies of the electromechanical devices in the harmonic characteristic table and the number of harmonic characteristics corresponding to each control frequency of the electromechanical devices are counted. Based on the number of harmonic characteristics corresponding to each control frequency, the total number of harmonic characteristics of the electromechanical devices is calculated. The total number of harmonic characteristics is divided by the number of control frequencies to obtain the control sensitivity. Determine the control post-stage for each device: For the operational stability and control sensitivity of each electromechanical device, the weights are assigned and summed using the weighting method. Based on the summation result, the electromechanical devices are sorted in ascending order, and each device is assigned an integer sequence number according to the sorting order, which serves as the control post-stage for that device.

8. The electromechanical equipment control method for building intelligent system integration according to claim 1, characterized in that: The method for forming the matching sequence code is as follows: The high-order bits of the matching sequence code are used as the control post-stage of each electromechanical device. The number of bits of the high-order bits is determined based on the number of bits of the maximum sequence number of the control post-stage. The low-order bits of the matching sequence code are used as the matching priority of the current harmonic type under the electromechanical device. The number of bits of the matching priority is determined based on the number of bits of the maximum sequence number of the matching priority. The two are combined to form a matching sequence code, and a unique matching sequence code is generated for each harmonic type of each device.

9. The electromechanical equipment control method for building intelligent system integration according to claim 1, characterized in that: The specific steps for determining whether electromechanical equipment needs adjustment are as follows: Determine the matching rate of electromechanical equipment under the previous power conditions: Under the same voltage, the ratio of the number of harmonic features that meet the harmonic elimination criteria matched according to the harmonic features corresponding to each electromechanical device to the number of harmonic features corresponding to that electromechanical device is used as the harmonic feature matching rate. By setting a matching threshold, electromechanical equipment that exceeds the matching threshold is determined to require regulation.

10. The electromechanical equipment control method for building intelligent system integration according to claim 1, characterized in that: The step of eliminating harmonic characteristics by adjusting the control frequency and then performing secondary matching for the electromechanical equipment that needs to be controlled is as follows: Set the range of control frequency for electromechanical equipment that needs to be controlled; According to the sequence of the control post-stages of the electromechanical equipment, in descending order of serial number, Select a control frequency within the control frequency range of each electromechanical device sequentially as a pre-control scheme. Based on the harmonic characteristic table, find the harmonic characteristics corresponding to the selected control frequency for each electromechanical device. The harmonic characteristics corresponding to the selected control frequency of each electromechanical device are vector-superimposed. A superimposed comprehensive harmonic characteristic is obtained, and the harmonic distortion rate of the comprehensive harmonic characteristic with respect to voltage and current is calculated. The harmonic elimination coefficient is obtained by summing the harmonic distortion rates of voltage and current. The pre-control scheme with the smallest harmonic elimination coefficient is selected as the control frequency of each electromechanical device for control.

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