Method of operating and monitoring an electric motor
By determining the desired speed range of the electric motor, the mechanical vibration and noise spectra of the electric motor and compressor are measured using MEMS transducers and microphones. Combined with FFT algorithm processing, noiseless and vibration-free operation of the electric motor and compressor assembly is achieved, solving the complexity and cost problems of control and monitoring in the prior art.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- MOTOR COMPETENCE CENT HLDG FLENSBURG
- Filing Date
- 2024-11-01
- Publication Date
- 2026-05-29
AI Technical Summary
Existing technologies make it difficult to control and monitor the operation of motor/compressor assemblies simply and reliably in a noiseless and vibration-free manner, and vibration sensors may fall off or increase costs.
By determining the desired speed range of the motor, the motor is run at multiple selected speeds, the motor correlation values are identified and processed, and the motor is run in a noise-free and vibration-free manner based on the processing results. The mechanical vibration and noise spectrum is measured using MEMS transducers and microphones, and the average value is calculated by combining algorithms such as FFT to select the speed with the lowest noise and vibration levels.
It achieves noiseless and vibration-free operation of the motor and compressor assembly, reduces mechanical vibration and noise levels, simplifies the control and monitoring process, and avoids sensor detachment and increased costs.
Smart Images
Figure CN122122391A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method, drive system, and motor system for operating a motor operatively connected to a compressor in a substantially noise-free and vibration-free manner using predetermined sets of motor association values, such as noise spectra within a defined audio frequency band. The invention also relates to a method for monitoring a motor operatively connected to a compressor by comparing predetermined sets of motor association values with determined or measured sets of motor association values. Background Technology
[0002] Controlling and monitoring the operation of an electric motor / compressor assembly in a noiseless and vibration-free manner can be a rather complex task, as vibration sensors may have to be mounted on or integrated with the electric motor / compressor assembly.
[0003] Vibration sensors fixed to the motor / compressor assembly may detach, while integrated vibration sensors may increase the overall production cost of the motor / compressor assembly.
[0004] Therefore, there is a need for a method that allows for simple and reliable control and monitoring of motor / compressor assemblies so that they can be operated in a substantially noiseless and vibration-free manner.
[0005] The purpose of embodiments of the present invention is to provide a simple method for controlling and monitoring an electric motor operatively connected to a compressor. Summary of the Invention
[0006] The above objective is achieved by providing, in a first aspect, a method for operating an electric motor operatively connected to a compressor in a substantially noiseless and vibration-free manner, the method comprising the steps of:
[0007] a) Provide the desired speed range for the electric motor.
[0008] b) Operate the motor at multiple selected speeds within the desired speed range, and determine a set of motor association values for each selected speed.
[0009] c) For each selected motor speed, process the determined set of motor association values, and
[0010] d) Based on the processing of the determined set of motor association values, operate the motor at that speed or within the speed range.
[0011] Therefore, according to a first aspect, the present invention relates to a method for operating an electric motor operatively connected to a compressor in a substantially noiseless and vibration-free manner. The electric motor may be a brushless DC motor / synchronous permanent magnet motor, and the compressor may be a reciprocating compressor pump. The electric motor and compressor can be used in portable cooling devices, such as portable cooling devices for cooling pharmaceuticals.
[0012] The desired speed range of an electric motor can, in principle, be any speed range, as long as the motor and compressor can handle it. The desired speed range can be provided in various ways, such as via a lookup table. Typically, the speed range can be below 10,000 rpm, for example, between 2,300 rpm and 4,500 rpm, with speed increments of, for example, 25 rpm, i.e., 2,300 rpm, 2,325 rpm, 2,350 rpm, etc.
[0013] A set of motor correlation values determined for each selected motor speed may include the spectrum derived from the mechanical motor excitation. In this context, mechanical motor / compressor excitation should be interpreted broadly, including, for example, the mechanical vibrations and / or pressure changes generated by the motor and / or compressor, in the form of noise, such as noise in the audio range between 20 Hz and 20 kHz. For the generated mechanical vibrations, vibration sensors can be used to determine the motor correlation values, while for the generated pressure changes in the form of noise, microphones can be used to determine the motor correlation values.
[0014] As will be discussed in further detail below, the source of measurable motor-related values (e.g., the form of pressure changes) is the mechanical vibration of the motor and / or compressor during operation.
[0015] The set of motor correlation values can be determined using one or more transducers, such as one or more pressure transducers, one or more accelerometers, one or more mechanical vibration transducers, etc. In one embodiment, the set of motor correlation values can be determined using one or more MEMS transducers. MEMS transducers have advantages due to their limited size.
[0016] In one embodiment, the set of motor correlation values may include a noise spectrum for each selected motor speed. This spectrum can be determined using one or more microphones, such as MEMS microphones, combined with appropriate processing algorithms, where the noise generated by the motor and / or compressor is measured and then processed, for example, using a Fast Fourier Transform (FFT). Other suitable processing algorithms may include cepstral analysis, waveform shape analysis, pulse counting, or bandpass filtering with RMS calculations.
[0017] It is advantageous to use one or more microphones, such as MEMS microphones, to determine the associated values of the set of motors, because the microphones can be placed at a distance relative to the motors and / or compressors.
[0018] To resolve unwanted interference, step b) can be repeated n times to repeatedly determine the set of motor association values for each selected speed. Furthermore, step c) may also involve calculating the average of the determined n sets of motor association values for each selected motor speed. Therefore, with each set of motor association values involving a spectrum, a total of n spectra (for each selected motor speed) are determined. The number of spectra n can be 2, 5, 10, 25, 50, 100, 150, 200, or even higher.
[0019] Then, the average of n frequency frequencies can be determined for each selected motor speed. The average can be calculated by selecting a desired frequency range and finding the maximum acceleration within that range. It's important to note that each motor / compressor speed has a corresponding "storage bin" capable of storing n acceleration values. Therefore, the maximum acceleration retrieved from the desired frequency range is "pushed" into this storage bin. In this context, "pushing" means discarding the oldest acceleration value and retaining the newest one. Thus, the "storage bin" will always contain the latest n acceleration values. Finally, the arithmetic mean is determined by adding the n acceleration values from the storage bin and dividing by n.
[0020] A lower average value is advantageous because it indicates a lower noise level from the motor and compressor. In one embodiment, method step d) may involve operating the motor at a speed with the lowest average value, i.e., operating the motor at a speed that produces minimal mechanical vibration and thus the lowest noise level.
[0021] In a second aspect, the present invention relates to a drive system configured to operate an electric motor operatively connected to a compressor in a substantially noiseless and vibration-free manner, the drive system including a controller configured to:
[0022] a) Operate the motor at multiple selected speeds within the desired speed range, and determine a set of motor association values for each selected speed.
[0023] b) For each selected motor speed, process the determined set of motor association values, and
[0024] c) Based on the processing of the determined set of motor association values, operate the motor at that speed or within the speed range.
[0025] Therefore, according to the second aspect, the present invention relates to a drive system for operating an electric motor operatively connected to a compressor in a substantially noiseless and vibration-free manner, i.e., a drive system for performing the method according to the first aspect.
[0026] Similarly, the electric motor can be a brushless DC motor / synchronous permanent magnet motor, while the compressor can be a reciprocating compressor pump. As mentioned above, the electric motor and compressor can be used in portable cooling devices, such as portable cooling devices for cooling pharmaceuticals.
[0027] The desired speed range of an electric motor can, in principle, be any speed range, as long as the motor and compressor can handle it, and the desired speed range can be provided, for example, from a lookup table. Typically, the speed range can be below 10,000 rpm, such as between 2,300 rpm and 4,500 rpm, with speed increments of, for example, 25 rpm, i.e., 2,300 rpm, 2,325 rpm, 2,350 rpm, etc.
[0028] Similar to the first aspect, the set of motor correlation values determined for each selected motor speed may include the spectrum derived from the mechanical motor excitation. In this context, mechanical motor / compressor excitation should be interpreted broadly, including, for example, pressure changes in the form of mechanical vibrations and / or noise generated by the motor and / or compressor, such as noise in the audio range between 20 Hz and 20 kHz. Likewise, for the generated mechanical vibrations, vibration sensors can be used to determine the motor correlation values, while for the generated noise-like pressure changes, microphones can be used to determine the motor correlation values.
[0029] The set of motor correlation values can be determined using one or more transducers, such as one or more pressure transducers, one or more accelerometers, one or more mechanical vibration transducers, etc. In one embodiment, the set of motor correlation values can be determined using one or more MEMS transducers. As mentioned above, MEMS transducers have advantages due to their limited size.
[0030] In one embodiment, the set of motor correlation values may include a noise spectrum for each selected motor speed. This spectrum can be determined using one or more microphones, such as MEMS microphones, combined with appropriate processing algorithms, wherein the noise generated by the motor and / or compressor is measured and then processed, for example, using FFT. Other suitable processing algorithms may include cepstral analysis, waveform shape analysis, pulse counting, or bandpass filtering with RMS calculations.
[0031] Similarly, it is advantageous to use one or more microphones, such as MEMS microphones, to determine the associated values of the set of motors, since the microphones can be placed at a distance relative to the motors and / or compressors.
[0032] To resolve unwanted interference, step a) can be repeated n times to determine the set of motor association values for each selected speed. Furthermore, step b) may involve calculating the average of the determined n sets of motor association values for each selected motor speed. Therefore, with each set of motor association values involving a spectrum, a total of n spectra (for each selected motor speed) are determined. The number of spectra n can be 2, 5, 10, 25, 50, 100, 150, 200, or even higher.
[0033] Then, the average of n frequency spectra can be determined for each selected motor speed. As mentioned above, the average can be calculated by selecting the desired frequency range and finding the maximum acceleration within that range. It's important to note that each motor / compressor speed has a corresponding "storage bin" capable of storing n acceleration values. Therefore, the maximum acceleration retrieved from the desired frequency range is "pushed" into this storage bin. In this context, "pushing" means discarding the oldest acceleration value and retaining the newest one. Thus, the "storage bin" will always contain the latest n acceleration values. Finally, the arithmetic mean is determined by adding the n acceleration values from the storage bin and dividing by n.
[0034] A lower average value is advantageous because it indicates a lower noise level from the motor and compressor. In one embodiment, method step c) may involve operating the motor at a speed with the lowest average value, i.e., operating the motor at a speed that produces minimal mechanical vibration and thus the lowest noise level.
[0035] In a third aspect, the present invention relates to an electric motor system comprising an electric motor and a drive system according to a second aspect for driving the electric motor.
[0036] In a fourth aspect, the present invention relates to a method for monitoring an electric motor operatively connected to a compressor, the method comprising the following steps:
[0037] a) Provide a predefined set of motor association values,
[0038] b) Run the motor at the selected speed and determine a set of motor association values.
[0039] c) Compare the predefined set of motor association values with the determined set of motor association values, and
[0040] d) If the deviation between the determined set of motor association values and the predefined set of motor association values exceeds a certain amount, the motor is controlled according to a predetermined arrangement.
[0041] Therefore, according to a fourth aspect, the present invention relates to a method for monitoring an electric motor operatively connected to a compressor.
[0042] The method according to the fourth aspect includes the following steps: comparing a predefined set of motor association values with a determined set of motor association values, and controlling the motors according to a predetermined arrangement if the deviation between the determined set of motor association values and the predefined set of motor association values exceeds a certain amount. This deviation, i.e., a deviation exceeding a certain amount, may indicate a fault in the motors and / or a fault in the compressor.
[0043] The specified quantity, that is, the deviation limit between a determined set of motor association values and a predefined set of motor association values, can be in the range of 1-40%, for example, in the range of 2-30%, for example, in the range of 3-25%, for example, in the range of 4-20%, for example, in the range of 5-15%, for example, in the range of 5-10%, or even a specific value. In the case of a specific value, a "do / don't do" method can be applied. Therefore, if the average value is lower than the specified value, no problem will occur. Otherwise, the algorithm may log an error message.
[0044] However, it is important to note that using different ranges is beneficial, as this helps identify whether the compressor is deteriorating over time. To determine this, the acceleration values should continue to be recorded relative to time.
[0045] Similarly, the electric motor can be a brushless DC motor / synchronous permanent magnet motor, while the compressor can be a reciprocating compressor pump. As mentioned above, the electric motor and compressor can be used in portable cooling devices, such as portable cooling devices for cooling pharmaceuticals.
[0046] In one embodiment, the predetermined arrangement of method step d) may involve changing the speed of the motor, such as increasing the speed of the motor, decreasing the speed of the motor, or bringing the motor to a complete stop.
[0047] In principle, the electric motor can operate at any speed, as long as the motor and compressor can handle it. Typically, the speed can be below 10,000 rpm, for example, between 2,300 rpm and 4,500 rpm. A predefined set of motor association values can be provided, for example, from a lookup table.
[0048] Similar to the first and second aspects, multiple sets of (predefined and determined) motor association values may include the spectrum derived from mechanical motor excitation. In this context, mechanical motor / compressor excitation should be interpreted broadly, including, for example, pressure changes in the form of mechanical vibrations and / or noise generated by the motor and / or compressor, such as noise in the audio range between 20 Hz and 20 kHz. Similarly, for the generated mechanical vibrations, vibration sensors can be used to determine the motor association values, while for the generated noise-like pressure changes, microphones can be used to determine the motor association values.
[0049] The set of motor correlation values can be determined using one or more transducers, such as one or more pressure transducers, one or more accelerometers, one or more mechanical vibration transducers, etc. In one embodiment, the set of motor correlation values can be determined using one or more MEMS transducers. MEMS transducers have advantages due to their limited size.
[0050] In one embodiment, a (predefined and determined) set of motor-related values may contain a noise spectrum. This spectrum can be determined using one or more MEMS microphones combined with appropriate processing algorithms, wherein the noise generated by the motor and / or compressor is measured and then processed, for example, using FFT. Other appropriate processing algorithms may include cepstral analysis, waveform shape analysis, pulse counting, or bandpass filtering with RMS calculation.
[0051] To resolve unwanted interference, step b) can be repeated n times to repeatedly determine the set of motor association values for the selected speed. Since each set of motor association values involves a spectrum, a total of n spectra are determined. The number of spectra n can be 2, 5, 10, 25, 50, 100, 150, 200, or even higher.
[0052] In summary, various aspects of the present invention can be combined and integrated in any possible manner within the scope of the invention. These and other aspects, features, and / or advantages of the invention will become apparent and will be elucidated with reference to the embodiments described below. Attached Figure Description
[0053] The invention will now be described in further detail with reference to the accompanying drawings, in which...
[0054] Figure 1 The diagram illustrates the setup for using one or more microphones to determine multiple sets of motor association values.
[0055] Figure 2 shows the determined noise spectrum.
[0056] Figure 3A flowchart is shown for a method of operating an electric motor operatively connected to a compressor in a substantially noiseless and vibration-free manner, and
[0057] Figure 4 A flowchart of a method for monitoring an electric motor operatively connected to a compressor according to the present invention is shown. Detailed Implementation
[0058] In general, the present invention relates to a method for operating an electric motor operatively connected to a compressor in a substantially noiseless and vibration-free manner. The method includes the steps of: operating the electric motor at a plurality of selected speeds within a desired speed range, and determining a set of motor association values for each selected speed; processing the determined set of motor association values for each selected motor speed, and operating the electric motor at that speed or within the speed range based on the processing of the determined set of motor association values. The invention also relates to an associated drive system configured to operate the electric motor operatively connected to the compressor in a substantially noiseless and vibration-free manner.
[0059] Furthermore, the present invention relates to a method for monitoring an electric motor operatively connected to a compressor. The method includes the steps of: comparing a predefined set of motor association values with a determined set of motor association values, and controlling the motor according to a predetermined arrangement if the deviation between the determined set of motor association values and the predefined set of motor association values exceeds a certain amount.
[0060] Figure 1 An electric motor 101 is shown operatively connected to a compressor 102 via a rotatable shaft 103. During operation of the electric motor 101 and compressor 102, mechanical vibrations occur due to minor mechanical imbalances in the electric motor 101, compressor 102, and rotatable shaft 103. As described above, the electric motor 101 can be a brushless DC motor / synchronous permanent magnet motor, while the compressor 102 can be a reciprocating compressor pump. Also as described above, the electric motor 101 and compressor 102 can be used, for example, in portable cooling devices for cooling pharmaceuticals. The electric motor 101 can be powered by a photovoltaic system (not shown) comprising multiple photovoltaic panels and / or by an available conventional AC power grid.
[0061] exist Figure 1 In this design, the mechanical vibrations generated by the electric motor 101, compressor 102, and rotatable shaft 103 are measured as pressure changes 105 and 106 (noise) using a suitable microphone 104, such as a MEMS microphone with appropriate sensitivity and frequency response. The correlation between mechanical vibrations and the resulting pressure changes will be discussed in detail with reference to Figure 2. Figure 1In an alternative approach, the mechanical vibrations generated by the motor 101, compressor 102, and rotatable shaft 103 can be measured using a vibration sensor / accelerometer, or by other devices mechanically coupled to at least the motor 101 and compressor 102.
[0062] Now back Figure 1 The pressure changes 105 and 106 measured by microphone 104 are processed by an appropriate algorithm in computer 107, such as an FFT algorithm. In this way, a spectrum representing the excitation of the mechanical motor / compressor can be generated based on the measured pressure changes in the form of noise.
[0063] Now go to Figure 2a The figure depicts two vibration curves, 201 and 202, of a mechanical electric motor within the frequency range of 100-1600 Hz. Vibration curve 201 is the average of three vibration curves, while vibration curve 202 is the average of 100 vibration curves. Both vibration curves 201 and 202 were measured using vibration sensors fixed to the PCB of the motor controller. Figure 2a The third acoustic curve 203, measured using a MEMS microphone, is also shown. An FFT algorithm was applied to derive the vibration / acoustic curves 201, 202, and 203.
[0064] like Figure 2a As shown, the correlation between vibration curves 201 and 202 and the third acoustic curve 203 is almost perfect. Therefore, the mechanical vibration spectrum of the motor, compressor, and / or the shaft connecting them can be determined solely by the third acoustic curve 203.
[0065] Figure 2b It shows Figure 2a In the amplification section within the frequency range of 700-1100 Hz, the correlation between vibration curves 201 and 202 and the third acoustic curve 203 is more obvious and clear.
[0066] Figure 3 A flowchart is shown for a method of operating an electric motor operatively connected to a compressor in a substantially noiseless and vibration-free manner. Figure 3 As shown, the following four steps:
[0067] a) Provide the desired speed range for the electric motor.
[0068] b) Operate the motor at multiple selected speeds within the desired speed range, and determine a set of motor association values for each selected speed.
[0069] c) For each selected motor speed, process the determined set of motor association values, and
[0070] d) Based on the processing of the determined set of motor association values, operate the motor at that speed or within the speed range.
[0071] Figure 3 The method steps described in the text can be, for example, by... Figure 1 The method is executed by the computer shown. Alternatively, it can be executed by a controller of a drive system configured to drive an electric motor and a compressor operatively connected to the motor.
[0072] Similarly, the electric motor can be a brushless DC motor / synchronous permanent magnet motor, while the compressor can be a reciprocating compressor pump. As mentioned above, the electric motor and compressor can be used in portable cooling devices, such as portable cooling devices for cooling pharmaceuticals.
[0073] As mentioned above, the desired speed range of the electric motor can, in principle, be any speed range, as long as the motor and compressor can handle that speed range. The desired speed range can be pre-stored and thus provided via a lookup table or similar storage arrangement. The speed range is typically up to 10,000 rpm, for example, between 2,300 rpm and 4,500 rpm, with speed increments (selected speeds) of, for example, 25 rpm, i.e., 2,300 rpm, 2,325 rpm, 2,350 rpm, etc.
[0074] A set of motor correlation values determined for each selected motor speed can be as follows: Figure 1 The diagram illustrates a method where one or more microphones, such as one or more MEMS microphones, measure changes in mechanical pressure excited by a mechanical motor / compressor. As mentioned above, other types of transducers can also be applied.
[0075] In this context, mechanical motor / compressor excitation should be interpreted broadly, including, for example, pressure changes in the form of mechanical vibrations and / or detectable noise generated by the motor and / or compressor. In a preferred embodiment, this set of motor-related values is determined using one or more pressure transducers, such as one or more MEMS microphones. MEMS microphones are advantageous due to their limited size.
[0076] As illustrated and discussed in conjunction with Figure 2, this set of motor-related values comprises the FFT spectrum of pressure changes measured by one or more MEMS microphones. As mentioned above, other suitable processing algorithms may include cepstral analysis, waveform shape analysis, pulse counting, or bandpass filtering with RMS calculations.
[0077] As described above, method step b) is preferably repeated n times to repeatedly determine the set of motor association values for each selected speed. Furthermore, method step c) preferably involves calculating the average of the determined n sets of motor association values for each selected motor speed. The number of determined spectra n can be 2, 5, 10, 25, 50, 100, 150, 200, or even higher. The average of the n spectra is then determined for each selected motor speed. This average can be determined as outlined above, i.e., by using a storage bin.
[0078] A lower average value is advantageous because a lower average value indicates a lower noise level from the motor and / or compressor, and thus also a lower mechanical vibration level from the motor and / or compressor. Preferably, method step d) involves operating the motor and compressor at a speed with the lowest average value, i.e., operating the motor and compressor at a speed that produces the lowest noise level due to the lowest level of mechanical vibration.
[0079] Now go to Figure 4 The figure depicts a flowchart of a method for monitoring an electric motor operatively connected to the compressor. Figure 4 As shown, the method includes the following four steps:
[0080] a) Provide a predefined set of motor association values,
[0081] b) Run the motor at the selected speed and determine a set of motor association values.
[0082] c) Compare a predefined set of motor association values with a determined set of motor association values, and
[0083] d) If the deviation between a determined set of motor association values and a predefined set of motor association values exceeds a certain amount, control the motors according to a predetermined arrangement.
[0084] Figure 4 The monitoring methods and procedures described in the document can also be... Figure 1 The method is executed by the computer shown. Alternatively, it can be executed by a controller of a drive system configured to drive an electric motor and a compressor operatively connected to the motor.
[0085] Similarly, the electric motor can be a brushless DC motor / synchronous permanent magnet motor, while the compressor can be a reciprocating compressor pump. As mentioned above, the electric motor and compressor can be used, for example, in portable cooling devices for cooling pharmaceuticals.
[0086] As mentioned above, a deviation exceeding a certain amount (between a defined set of motor association values and a predefined set of motor association values) may indicate a motor malfunction and / or a compressor malfunction. This certain amount, i.e., the deviation limit between the defined set of motor association values and the predefined set of motor association values, can be in the range of 1-40%, such as 2-30%, 3-25%, 4-20%, 5-15%, 5-10%, or even a specific value. In the case of a specific value, a "do / don't do" approach can be applied. Therefore, if the average value is below the specified value, no problem will occur. Otherwise, the algorithm may log an error message.
[0087] However, it is important to note that using different ranges is beneficial, as this helps identify whether the compressor is deteriorating over time. To determine this, the acceleration values should continue to be recorded relative to time.
[0088] The step of comparing a defined set of motor association values with a predefined set of motor association values, i.e., method step d), may involve changing the speed of the motor, such as increasing the speed of the motor, decreasing the speed of the motor, or even stopping the motor completely.
[0089] Regarding step b), in principle, the motor can be operated at any speed, as long as the motor and compressor can handle that speed. Typically, the motor speed is below 10,000 rpm, for example, between 2,300 rpm and 4,500 rpm.
[0090] A predefined set of motor association values can be stored in advance and thus provided via a lookup table or similar storage arrangement.
[0091] Regarding a (predefined and defined) set of motor association values, these motor association values may include the spectrum derived from mechanical motor excitation. In this context, mechanical motor / compressor excitation should be interpreted broadly, including, for example, mechanical vibrations generated by the motor and / or compressor and pressure changes in the form of detectable noise generated by the motor and / or compressor.
[0092] In a preferred embodiment, the set of motor correlation values is determined using one or more pressure transducers, such as one or more MEMS microphones. MEMS microphones are advantageous due to their limited size. As mentioned above, other types of transducers may also be applicable. As depicted and discussed in conjunction with Figure 2, the set of motor correlation values comprises the FFT spectrum of pressure changes measured by one or more MEMS microphones. As mentioned above, other suitable processing algorithms may include cepstral analysis, waveform shape analysis, pulse counting, or bandpass filtering with RMS calculation.
[0093] To resolve unwanted interference, step b) can be repeated n times to repeatedly determine the set of motor association values for the selected speed. If each set of motor association values involves a spectrum, then a total of n spectra need to be determined. The number of spectra n can be 2, 5, 10, 25, 50, 100, 150, 200, or even higher.
[0094] Although the invention has been discussed above with reference to exemplary embodiments thereof, the invention is not limited to these specific embodiments, which may be modified in various ways without departing from the invention. Therefore, the exemplary embodiments discussed should not be used to strictly interpret the appended claims in accordance with them. Rather, these embodiments are intended only to interpret the wording of the appended claims and not to limit the claims to these exemplary embodiments. Thus, the scope of protection of the invention should be interpreted solely according to the appended claims, wherein any ambiguity that may arise in the wording of the claims should be resolved using these exemplary embodiments.
Claims
1. A method for operating an electric motor operatively connected to a compressor in a substantially noiseless and vibration-free manner, the method comprising the steps of: a) Provide the desired speed range for the electric motor. b) Operate the motor at multiple selected speeds within the desired speed range, and determine a set of motor association values for each selected speed. c) For each selected motor speed, process the determined set of motor association values, and d) Based on the processing of the determined set of motor association values, operate the motor at that speed or within the speed range.
2. The method according to claim 1, wherein the set of motor association values determined for each selected motor speed comprises the spectrum of the mechanical motor excitation.
3. The method according to claim 1 or 2, wherein the set of motor association values is determined using one or more transducers, such as one or more MEMS transducers.
4. The method according to any of the preceding claims, wherein step b) is repeated n times to determine the set of motor association values n times for each selected speed, and wherein step c) involves calculating the average of the determined set of n motor association values for each selected motor speed.
5. The method according to claim 4, wherein step d) involves operating the motor at a speed having the lowest average value.
6. The method according to any of the preceding claims, wherein the desired speed range of the electric motor is less than 10,000 rpm.
7. A drive system configured to operate an electric motor operatively connected to a compressor in a substantially noiseless and vibration-free manner, the drive system including a controller configured to: a) Operate the motor at multiple selected speeds within the desired speed range, and determine a set of motor association values for each selected speed. b) For each selected motor speed, process the determined set of motor association values, and c) Based on the processing of the determined set of motor association values, operate the motor at that speed or within the speed range.
8. The drive system according to claim 7, wherein the set of motor correlation values determined for each selected motor speed includes the spectrum of the mechanical motor excitation.
9. The drive system according to claim 7 or 8 further includes one or more transducers, such as one or more MEMS transducers, for measuring the set of motor correlation values.
10. The drive system according to any one of claims 7-9, wherein the controller is configured to repeat step a) n times to repeatedly determine the set of motor association values for each selected speed n times, and is configured to calculate the average of the determined set of n motor association values with respect to step b) for each selected motor speed.
11. The drive system according to claim 10, wherein the controller is configured to operate the motor at a speed having the lowest average value in relation to step d).
12. An electric motor system comprising an electric motor and a drive system for driving the electric motor according to any one of claims 7-11.
13. A method for monitoring an electric motor operatively connected to a compressor, the method comprising the steps of: a) Provide a predefined set of motor association values, b) Run the motor at the selected speed and determine a set of motor association values. c) Compare the predefined set of motor association values with the determined set of motor association values, and d) If the deviation between the determined set of motor association values and the predefined set of motor association values exceeds a certain amount, the motor is controlled according to a predetermined arrangement.
14. The method according to claim 13, wherein step d) involves changing the speed of the electric motor, for example, bringing the electric motor to a complete stop.
15. The method according to claim 13 or 14, wherein the determined set of motor correlation values includes the spectrum of mechanical motor excitation.
16. The method according to any one of claims 13-15, wherein the set of motor association values is determined using one or more transducers, such as one or more MEMS transducers.