Control method and device of magnetic levitation system, magnetic levitation system and storage medium

Abstract

The application discloses a kind of control method, device, magnetic suspension system and storage medium of magnetic suspension system, the method includes: before being suspended after being powered on on magnetic suspension bearing, the first direct current voltage peak value that the sinusoidal wave signal detected by first eddy current displacement sensor is exported after first peak detection circuit, the second direct current voltage peak value that the sinusoidal wave signal detected by second eddy current displacement sensor is exported after second peak detection circuit;After magnetic suspension bearing is suspended, the current operating frequency of compressor is acquired;According to first direct current voltage peak value and second direct current voltage peak value, the current operating frequency of compressor, the current capacity of capacitance module is adjusted.The scheme, by using peak detection circuit to process the sinusoidal wave signal generated by eddy current displacement sensor obtains the voltage signal of the shaft displacement of magnetic suspension bearing, and according to the current operating frequency of compressor, the parameter of peak detection circuit is adjusted, and the sensitivity of magnetic suspension bearing control is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of magnetic suspension system, and particularly relates to a control method and device of a magnetic suspension system, the magnetic suspension system and a storage medium, and especially relates to a method, device, magnetic suspension system and storage medium for detecting displacement of a magnetic suspension bearing in a magnetic suspension system by using an eddy current displacement sensor and a peak detection circuit and controlling the magnetic suspension system based on the displacement. BACKGROUND

[0002] In the magnetic suspension system, the magnetic suspension bearing can be stably suspended to become the key to the stable operation of the magnetic suspension centrifugal unit. Since the magnetic suspension bearing is in a suspended state, the detection of the position of the magnetic suspension bearing is also very important. The eddy current displacement sensor is used in cooperation with the differential amplification circuit to detect the position of the magnetic suspension bearing, which is called eddy current detection.

[0003] In the control of the magnetic suspension bearing, the sinusoidal signals generated by the two eddy current displacement sensors are differentially amplified by the differential amplification circuit to obtain the voltage signal of the shaft displacement of the magnetic suspension bearing. The position of the shaft can be determined through the voltage signal of the shaft displacement, that is, the position of the magnetic suspension bearing is detected. However, the actual value of the voltage signal of the shaft displacement output by the differential amplification circuit is lower than the true value, which makes the detection accuracy of the position of the magnetic suspension bearing poor, resulting in low sensitivity of the control of the magnetic suspension bearing and affecting the stability of the magnetic suspension system.

[0004] The above content is only used to assist in understanding the technical solutions of the present application and does not represent the acknowledgement of the above content as prior art. SUMMARY

[0005] The present application aims to provide a control method and device of a magnetic suspension system, the magnetic suspension system and a storage medium to solve the problem that in the detection of the position of the magnetic suspension bearing, the sinusoidal signals generated by two eddy current displacement sensors are differentially amplified by the differential amplification circuit to obtain the voltage signal of the shaft displacement of the magnetic suspension bearing. However, the actual value of the voltage signal of the shaft displacement output by the differential amplification circuit is lower than the true value, which makes the detection accuracy of the position of the magnetic suspension bearing poor, resulting in low sensitivity of the control of the magnetic suspension bearing and affecting the stability of the magnetic suspension system. The effect of improving the stability of the magnetic suspension system is achieved by using the peak detection circuit to process the sinusoidal signals generated by the eddy current displacement sensor to obtain the voltage signal of the shaft displacement of the magnetic suspension bearing in the detection of the position of the magnetic suspension bearing, and adjusting the parameters of the analog peak storage in the peak detection circuit according to the current operating frequency of the compressor. Since the actual value of the voltage signal of the shaft displacement output by the peak detection circuit is closer to the true value, the detection accuracy of the position of the magnetic suspension bearing is better, which is conducive to improving the sensitivity of the control of the magnetic suspension bearing and further improving the stability of the magnetic suspension system.

[0006] The application provides a control method of a magnetic suspension system, the magnetic suspension system comprising a magnetic suspension bearing; first and second eddy current displacement sensors are symmetrically arranged on the inner wall of a compressor cavity in the radial direction of the magnetic suspension bearing; a first peak detection circuit is arranged at the output end of the first eddy current displacement sensor, and a second peak detection circuit is arranged at the output end of the second eddy current displacement sensor; the analog peak storage in the first peak detection circuit and the analog peak storage in the second peak detection circuit both adopt a capacitor module with adjustable capacitance; the control method of the magnetic suspension system comprises the following steps: before the magnetic suspension bearing is powered on and suspended, the peak value of a direct current voltage signal output by the first peak detection circuit after a sinusoidal signal detected by the first eddy current displacement sensor is recorded as a first direct current voltage peak value; and the peak value of a direct current voltage signal output by the second peak detection circuit after a sinusoidal signal detected by the second eddy current displacement sensor is recorded as a second direct current voltage peak value; after the magnetic suspension bearing is suspended, the operating frequency of the compressor in the magnetic suspension system is recorded as the current operating frequency of the compressor; and the current capacitance of the capacitor module is adjusted according to the first and second direct current voltage peak values and the current operating frequency of the compressor in the magnetic suspension system.

[0007] In some embodiments, the current capacitance of the capacitor module is adjusted according to the first and second direct current voltage peak values and the current operating frequency of the compressor in the magnetic suspension system, which comprises the following steps: the current capacitance range of the capacitor module is determined according to the first and second direct current voltage peak values; after the magnetic suspension bearing is suspended, the operating frequency of the compressor in the magnetic suspension system is recorded as the current operating frequency of the compressor; and the current capacitance of the capacitor module is adjusted within the current capacitance range according to the current operating frequency of the compressor.

[0008] In some embodiments, the current operating frequency of the compressor is within a preset frequency range of the compressor; the preset frequency range of the compressor comprises n frequency intervals; the n frequency intervals comprise a first frequency interval, a second frequency interval to an n-th frequency interval in which the frequency values increase sequentially, and n is a positive integer; the adjustment of the current capacitance value of the capacitor module according to the current operating frequency of the compressor within the current capacitance range of the capacitor module comprises: dividing the current capacitance range of the capacitor module into n capacitance intervals corresponding to the n frequency intervals in the preset frequency range of the compressor; the n capacitance intervals comprise a first capacitance interval, a second capacitance interval to an n-th capacitance interval in which the capacitance values decrease sequentially; wherein the first capacitance interval corresponds to the first frequency interval; and adjusting the current capacitance value of the capacitor module to a capacitance value in the capacitance interval corresponding to the frequency interval in which the current operating frequency of the compressor is located in the preset frequency range of the compressor.

[0009] In some embodiments, the current operating frequency of the compressor is within a preset frequency range of the compressor; the preset frequency range of the compressor comprises n frequency intervals; the n frequency intervals comprise a first frequency interval, a second frequency interval to an n-th frequency interval in which the frequency values increase sequentially, and n is a positive integer; the adjustment of the current capacitance value of the capacitor module according to the current operating frequency of the compressor within the current capacitance range of the capacitor module further comprises: determining a maximum capacitance value of the capacitor module within the current capacitance range of the capacitor module; determining the frequency interval in which the current operating frequency of the compressor is located in the preset frequency range of the compressor, and adjusting the maximum capacitance value of the capacitor module by a set proportion corresponding to the position of the frequency interval in the preset frequency range of the compressor to obtain an adjusted capacitance value of the capacitor module; wherein the greater the current operating frequency of the compressor, the smaller the adjusted capacitance value of the capacitor module; and controlling a capacitance adjustment end of the capacitor module to adjust the current capacitance value of the capacitor module to the adjusted capacitance value of the capacitor module to achieve the adjustment of the current capacitance value of the capacitor module.

[0010] In some embodiments, further comprising: after adjusting the current capacitance value of the capacitance module, obtaining a peak value of a direct current voltage signal output by the sinusoidal wave signal detected by the first eddy current displacement sensor after passing through the first peak detection circuit, denoted as a third direct current voltage peak value; and obtaining a peak value of a direct current voltage signal output by the sinusoidal wave signal detected by the second eddy current displacement sensor after passing through the second peak detection circuit, denoted as a fourth direct current voltage peak value; determining a displacement signal of the magnetic bearing according to the third direct current voltage peak value and the fourth direct current voltage peak value; and controlling the operation of the magnetic bearing according to the displacement signal of the magnetic bearing to achieve control of the magnetic suspension system.

[0011] In another aspect, the present application provides a control device for a magnetic suspension system, the magnetic suspension system having a magnetic bearing; the inner wall of a compressor inner cavity in the magnetic suspension system is symmetrically provided with a first eddy current displacement sensor and a second eddy current displacement sensor along the radial direction of the magnetic bearing; a first peak detection circuit is arranged at the output end of the first eddy current displacement sensor, and a second peak detection circuit is arranged at the output end of the second eddy current displacement sensor; the analog peak storage in the first peak detection circuit and the analog peak storage in the second peak detection circuit both use a capacitance module with an adjustable capacitance value; the control device for the magnetic suspension system comprises: an obtaining unit configured to, before the magnetic bearing is floated after being powered on, obtain a peak value of a direct current voltage signal output by the sinusoidal wave signal detected by the first eddy current displacement sensor after passing through the first peak detection circuit, denoted as a first direct current voltage peak value; and obtain a peak value of a direct current voltage signal output by the sinusoidal wave signal detected by the second eddy current displacement sensor after passing through the second peak detection circuit, denoted as a second direct current voltage peak value; the obtaining unit is further configured to, after the magnetic bearing is floated, obtain the operating frequency of the compressor in the magnetic suspension system, denoted as the current operating frequency of the compressor; and a control unit configured to adjust the current capacitance value of the capacitance module according to the first direct current voltage peak value and the second direct current voltage peak value, and the current operating frequency of the compressor in the magnetic suspension system.

[0012] In some embodiments, the control unit adjusts the current capacitance value of the capacitor module according to the first DC voltage peak value and the second DC voltage peak value and the current operating frequency of the compressor in the magnetic suspension system, including: determining the current capacitance value range of the capacitor module according to the first DC voltage peak value and the second DC voltage peak value; obtaining the operating frequency of the compressor in the magnetic suspension system after the magnetic suspension bearing is suspended, denoted as the current operating frequency of the compressor; and adjusting the current capacitance value of the capacitor module in the current capacitance value range of the capacitor module according to the current operating frequency of the compressor.

[0013] In some embodiments, the current operating frequency of the compressor is within the preset frequency range of the compressor; the preset frequency range of the compressor includes n frequency intervals; the n frequency intervals include a first frequency interval, a second frequency interval to an n-th frequency interval with sequentially increasing frequency values, and n is a positive integer; and the control unit adjusts the current capacitance value of the capacitor module in the current capacitance value range of the capacitor module according to the current operating frequency of the compressor, including: dividing the current capacitance value range of the capacitor module into n capacitance value intervals corresponding to the n frequency intervals in the preset frequency range of the compressor; the n capacitance value intervals include a first capacitance value interval, a second capacitance value interval to an n-th capacitance value interval with sequentially decreasing capacitance values; wherein the first capacitance value interval corresponds to the first frequency interval; and adjusting the current capacitance value of the capacitor module to the capacitance value in the capacitance value interval corresponding to the frequency interval in which the current operating frequency of the compressor is located in the preset frequency range of the compressor.

[0014] In some embodiments, the current operating frequency of the compressor is within a preset frequency range of the compressor; the preset frequency range of the compressor comprises n frequency intervals; the n frequency intervals comprise a first frequency interval, a second frequency interval to an n frequency interval in which the frequency values increase sequentially, and n is a positive integer; the control unit adjusts the current capacitance value of the capacitor module according to the current operating frequency of the compressor within the current capacitance value range of the capacitor module, and further comprises: determining the maximum capacitance value of the capacitor module within the current capacitance value range of the capacitor module; determining the frequency interval in which the current operating frequency of the compressor is located in the preset frequency range of the compressor, and reducing the maximum capacitance value of the capacitor module by a set proportion corresponding to the position of the frequency interval in the preset frequency range of the compressor to obtain the adjusted capacitance value of the capacitor module; wherein the greater the current operating frequency of the compressor, the smaller the adjusted capacitance value of the capacitor module; and controlling the capacitance adjustment end of the capacitor module to take the adjusted capacitance value of the capacitor module as the current capacitance value of the capacitor module to adjust the current capacitance value of the capacitor module.

[0015] In some embodiments, the acquisition unit is further configured to, after adjusting the current capacitance value of the capacitor module, acquire a peak value of a direct current voltage signal output by the first eddy current displacement sensor after the sinusoidal wave signal detected by the first eddy current displacement sensor passes through the first peak detection circuit, denoted as a third direct current voltage peak value; and acquire a peak value of a direct current voltage signal output by the second eddy current displacement sensor after the sinusoidal wave signal detected by the second eddy current displacement sensor passes through the second peak detection circuit, denoted as a fourth direct current voltage peak value; the control unit is further configured to determine the displacement signal of the magnetic suspension bearing according to the third direct current voltage peak value and the fourth direct current voltage peak value; and the control unit is further configured to control the operation of the magnetic suspension bearing according to the displacement signal of the magnetic suspension bearing to realize the control of the magnetic suspension system.

[0016] To match the above device, the application further provides a magnetic suspension system comprising the above-mentioned control device of the magnetic suspension system.

[0017] To match the above method, the application further provides a storage medium comprising a stored program, wherein when the program is running, the device in which the storage medium is located performs the above-mentioned control method of the magnetic suspension system.

[0018] Therefore, the scheme of the present application, by in the position detection of magnetic suspension bearing, each of the upper and lower distribution of an eddy current displacement sensor in the magnetic suspension bearing, in the output end of each peak detection circuit corresponding to the peak value of the eddy current displacement sensor; The analog peak value storage in each peak detection circuit adopts adjustable capacitor; Before the operation of the magnetic suspension bearing, the upper and lower positions of the magnetic suspension bearing are detected, the output of the two eddy current displacement sensor peak detection circuit is obtained, the maximum value of the two direct current voltage is set according to the adjustable capacitor; Corresponding to the interval of the frequency range of the current running frequency of the compressor, the set value of the adjustable capacitor is divided into corresponding interval; After the magnetic suspension bearing is stably suspended, the current running frequency of the compressor is obtained under the operation of the magnetic suspension system, and the interval corresponding to the value of the adjustable capacitor is adjusted according to the interval of the frequency range of the current running frequency of the compressor, so that, by in the position detection of magnetic suspension bearing, the sine wave signal generated by the eddy current displacement sensor is processed by the peak detection circuit to obtain the voltage signal of the shaft displacement of the magnetic suspension bearing, and the parameter of the analog peak value storage in the peak detection circuit is adjusted according to the current running frequency of the compressor, since the actual value of the shaft displacement voltage signal output by the peak detection circuit is closer to the true value, the position detection accuracy of the magnetic suspension bearing is better, which is beneficial to improve the sensitivity of the magnetic suspension bearing control, and further improve the stability of the magnetic suspension system.

[0019] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application.

[0020] The technical scheme of the present application will be described in detail below by means of the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 Flowchart of an embodiment of the control method of the magnetic suspension system of the present application;

[0022] Figure 2 Flowchart of an embodiment of the method of the present application for adjusting the current value of the capacitor module according to the first direct current voltage peak value and the second direct current voltage peak value, and the current running frequency of the compressor in the magnetic suspension system;

[0023] Figure 3 Flowchart of an embodiment of the first process of adjusting the current value of the capacitor module in the current value range of the capacitor module according to the current running frequency of the compressor in the method of the present application;

[0024] Figure 4Flow chart of an embodiment of a second process for adjusting the current capacitance of the capacitor module according to the current operating frequency of the compressor in the method of the application within the current capacitance range of the capacitor module;

[0025] Figure 5 Flow chart of an embodiment of the control after adjusting the current capacitance of the capacitor module in the method of the application;

[0026] Figure 6 Structure diagram of an embodiment of the control device of the magnetic suspension system of the application;

[0027] Figure 7 Detection structure diagram of the eddy current displacement sensor in the related scheme;

[0028] Figure 8 Distribution structure diagram of the bearing and the eddy current displacement sensor in the application;

[0029] Figure 9 Structure diagram of the peak detection circuit in the application;

[0030] Figure 10 Comparison waveform diagram of the output results of the peak detection circuit in the application and the differential amplification circuit in the related scheme;

[0031] Figure 11 Flow chart of controlling the peak detection circuit;

[0032] Figure 12 Effect curve diagram of the signal peak detection sensitivity of the eddy current displacement sensor in the application.

[0033] In combination with the drawings, the following are the meanings of the reference signs in the embodiments of the application:

[0034] 102 - acquisition unit; 104 - control unit. DETAILED DESCRIPTION

[0035] In order to make the objects, technical solutions and advantages of the application clearer, the technical solutions of the application will be described clearly and completely below in combination with the embodiments of the application and the corresponding drawings. Obviously, the described embodiments are only some of the embodiments of the application, but not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0036] Figure 7 Detection structure diagram of the eddy current displacement sensor in the related scheme. As shown in FIG. 1, the eddy current displacement sensor in the related scheme includes a coil 101, a core 102, a magnetic field 103 and a magnetic field detection circuit 104. Figure 7As shown, the eddy current displacement sensor comprises a probe and a preamplifier. The probe comprises a fixed frequency amplitude modulation circuit, and the fixed frequency amplitude modulation circuit comprises a resistor R, a capacitor C and an inductor L. The preamplifier comprises an amplification circuit, a detection circuit, a filter circuit and an oscillator. The capacitor C and the inductor L are connected in parallel to form a parallel resonance circuit, a first end of the parallel resonance circuit is grounded, and a second end of the parallel resonance circuit is connected to a first terminal of an output voltage U1 of the oscillator through the resistor R, and a second terminal of the output voltage U1 of the oscillator is grounded. The second end of the parallel resonance circuit and the common terminal of the resistor R are connected to an output terminal of a sensor signal output through the amplification circuit, the detection circuit and the filter circuit, and the output terminal of the sensor signal output can output a sensor output signal (such as a sine wave signal generated by the eddy current displacement sensor).

[0037] Referring to Figure 7 As shown in the example, the detection principle of the eddy current displacement sensor is that a magnetic field signal is emitted by the probe coil, when the probe is close to the metal (i.e. the measured target), the metal returns a magnetic field signal opposite to the direction of the magnetic field signal of the probe coil, attenuates the original magnetic field signal of the probe coil, and changes the amplitude and phase of the sine wave signal generated by the original parallel resonance circuit (i.e. the LC resonance circuit composed of the inductor L and the capacitor C). In the control of the magnetic suspension bearing, the sine wave signals generated by the two eddy current displacement sensors are differentiated to obtain a voltage signal of the shaft displacement of the magnetic suspension bearing, and through the voltage signal of the shaft displacement, the position of the shaft can be determined, i.e. the position of the magnetic suspension bearing is detected. After the eddy current displacement sensor detects and outputs the sine wave signal, the actual value obtained after the sine wave signal is amplified by the differential amplifier circuit is lower than the true value, which leads to low sensitivity of the magnetic suspension bearing control, poor suspension accuracy of the magnetic suspension bearing, and poor stability of the magnetic suspension system.

[0038] The differential amplifier circuit has a filtering function. The true value referred to herein is the peak value (i.e. the peak value of the sine wave signal). Because the sampling range of the differential amplifier circuit is determined by the input voltage and the parameters of the operational amplifier element, the peak value may not be collected. At the same time, some peak values may be filtered out by the filtering function.

[0039] Therefore, the scheme of the present application proposes a control method of a magnetic suspension system, specifically, a peak detection circuit of an eddy current displacement sensor is arranged, a method for detecting the displacement of a magnetic suspension bearing in the magnetic suspension system by using the eddy current displacement sensor and the peak detection circuit and controlling the magnetic suspension system based on the displacement is used, the actual value of the sine wave signal generated by the eddy current displacement sensor can be infinitely close to the true value (i.e. the peak value of the sine wave signal), the problem that the sensitivity of the differential amplification circuit for identifying the sine wave signal generated by the eddy current displacement sensor is not high can be solved, and the sensitivity of the magnetic suspension bearing control is improved; and the parameters of the corresponding peak detection circuit can be automatically adjusted according to the different operating frequencies of the magnetic suspension bearing, and the accuracy of the magnetic suspension bearing control is improved.

[0040] According to the embodiment of the present application, a control method of a magnetic suspension system is provided, as shown in Figure 1 The flowchart of an embodiment of the method of the present application is shown in the figure. The magnetic suspension system has a magnetic suspension bearing, of course, also has a bearing controller, that is, the magnetic suspension system has a magnetic suspension bearing and a bearing controller; the inner wall of the inner cavity of the compressor in the magnetic suspension system is symmetrically provided with a first eddy current displacement sensor and a second eddy current displacement sensor along the radial direction of the magnetic suspension bearing, for example, the first eddy current displacement sensor and the second eddy current displacement sensor are distributed above and below the magnetic suspension bearing, the first eddy current displacement sensor is, for example, an eddy current displacement sensor N, and the second eddy current displacement sensor is, for example, an eddy current displacement sensor M. Among them, the displacement sensor is placed on the inner wall of the inner cavity of the compressor, and the position detected by the displacement sensor is actually the distance between the magnetic suspension bearing and the inner wall of the inner cavity of the compressor.

[0041] Specifically, Figure 8 The distribution structure of the bearing and the eddy current displacement sensor in the present application is shown in the figure. Figure 8 The positional relationship between the magnetic suspension bearing and the eddy current displacement sensor can be shown, and one eddy current displacement sensor is distributed above and below the magnetic suspension bearing. Figure 8 Four direction eddy current displacement sensors are arranged in the present application, so that the capacitance value of the adjustable capacitor C1 required in the scheme of the present application can be obtained when the magnetic suspension bearing is on and the floating shaft is not used. In the scheme of the present application, two displacement sensors are actually required for measurement, i.e. the upper and lower displacement sensors, Figure 8 The left and right displacement sensors in the example shown are used in the state that the magnetic suspension bearing is suspended and operated. The outputs of the four displacement sensors are composed of peak detection circuits, but only the upper and lower displacement sensors are used for Umax and Umin detection; the use of the peak detection circuit of the left and right displacement sensors can make the measurement accuracy more accurate.

[0042] The output end of the first eddy current displacement sensor is provided with a first peak detection circuit, and the output end of the second eddy current displacement sensor is provided with a second peak detection circuit; specifically, the first peak detection circuit is arranged between the output end of the first eddy current displacement sensor and the bearing controller, and the second peak detection circuit is arranged between the output end of the second eddy current displacement sensor and the bearing controller; the analog peak storage in the first peak detection circuit and the analog peak storage in the second peak detection circuit both adopt a capacitance module with adjustable capacitance, such as an adjustable capacitor C1; the first peak detection circuit and the second peak detection circuit have the same structure. Figure 9 It is a structural schematic diagram of the peak detection circuit in the application. Figure 9 As shown in the figure, the peak detection circuit comprises an operational amplifier U1, an operational amplifier U2, a diode D1, a diode D2, an adjustable capacitor C1, a resistor R1, a resistor R2, an ADC module, and a monitoring control chip MCU. The adjustable capacitor C1 is used as an analog peak storage. The diode D1 and the diode D2 are used as one-way power switches. The resistor R1 is used as an input-output buffer isolation device. Figure 9 In the example shown in the figure, the sine wave signal output by the eddy current displacement sensor N is input to the non-inverting input end of the operational amplifier U1; the inverting input end of the operational amplifier U1 is connected to the inverting input end of the operational amplifier U2 through the resistor R1. The output end of the operational amplifier U1 is connected to the cathode of the diode D2, and the anode of the diode D2 is connected to the common end of the inverting input end of the operational amplifier U1 and the resistor R1. The output end of the operational amplifier U1 is connected to the anode of the diode D1; the cathode of the diode D1 is connected to the non-inverting input end of the operational amplifier U2. The cathode of the diode D1 and the common end of the operational amplifier U2 are connected to the ground through the parallel adjustable capacitor C1 and the resistor R2. The output end of the operational amplifier U2 outputs a direct current voltage signal Un as the displacement collection signal of the eddy current displacement sensor N. The output end of the operational amplifier U2 is input to the input end of the monitoring control chip MCU after data collection by the ADC module. The output end of the monitoring control chip MCU outputs a control signal to the adjustment end of the adjustable capacitor C1.

[0043] In the scheme of the application, as shown in the figure, Figure 1 The control method of the magnetic suspension system comprises steps S110 to S130.

[0044] At step S110, before the magnetic suspension bearing is floated after being powered on, the peak value of the direct current voltage signal output by the sinusoidal wave signal detected by the first eddy current displacement sensor through the first peak detection circuit is obtained, denoted as a first direct current voltage peak value; and the peak value of the direct current voltage signal output by the sinusoidal wave signal detected by the second eddy current displacement sensor through the second peak detection circuit is obtained, denoted as a second direct current voltage peak value. Wherein, the first direct current voltage peak value is like a minimum value Umin, and the second direct current voltage peak value is like a maximum value Umax.

[0045] At step S120, after the magnetic suspension bearing is floated, the operating frequency of the compressor in the magnetic suspension system is obtained, denoted as the current operating frequency of the compressor.

[0046] At step S130, according to the first direct current voltage peak value and the second direct current voltage peak value, and the current operating frequency of the compressor in the magnetic suspension system, the current capacitance value of the capacitance module is adjusted to: use the first peak detection circuit and the second peak detection circuit after the capacitance value is adjusted to detect the floating position of the magnetic suspension bearing, and control the operation of the magnetic suspension system according to the detection result of the floating position of the magnetic suspension bearing.

[0047] The peak detection circuit of the eddy current displacement sensor provided by the scheme of the present application can accurately identify the peak value of the sinusoidal wave signal generated by the eddy current displacement sensor by using the peak detection circuit of the eddy current displacement sensor, so that the actual value of the sinusoidal wave signal generated by the eddy current displacement sensor is infinitely close to the true value (i.e. the peak value of the sinusoidal wave signal), thereby outputting an accurate direct current voltage signal, which can solve the problem of low sensitivity of the differential amplification circuit in identifying the sinusoidal wave signal generated by the eddy current displacement sensor, and improve the sensitivity of the magnetic suspension bearing control. Moreover, based on different operating frequencies of the magnetic suspension bearing, the parameters of the peak detection circuit in the scheme of the present application are automatically adjusted according to the corresponding frequency, that is, the parameters of the corresponding peak detection circuit are automatically adjusted according to the different operating frequencies of the magnetic suspension bearing, so as to adapt to the peak detection circuit parameters under different operating frequencies of the magnetic suspension bearing. The parameters of the corresponding peak detection circuit can be automatically identified and adjusted under different rotating speeds, further improving the accuracy of the magnetic suspension bearing control.

[0048] In some embodiments, the current capacitance value of the capacitance module is adjusted according to the first DC voltage peak value and the second DC voltage peak value and the current operating frequency of the compressor in the magnetic suspension system in step S130, so as to detect the suspension position of the magnetic suspension bearing by using the first peak detection circuit and the second peak detection circuit after the capacitance value adjustment, and control the operation of the magnetic suspension system according to the detection result of the suspension position of the magnetic suspension bearing. See the following exemplary description.

[0049] The following will be further described in combination with Figure 2 the flowchart of an embodiment of the method of the present application for adjusting the current capacitance value of the capacitance module according to the first DC voltage peak value and the second DC voltage peak value and the current operating frequency of the compressor in the magnetic suspension system, which further illustrates the specific process of adjusting the current capacitance value of the capacitance module according to the first DC voltage peak value and the second DC voltage peak value and the current operating frequency of the compressor in the magnetic suspension system in step S130, including steps S210 to S230.

[0050] In step S210, the current capacitance value range of the capacitance module is determined according to the first DC voltage peak value and the second DC voltage peak value.

[0051] In step S220, after the magnetic suspension bearing is suspended, the current capacitance value of the capacitance module is adjusted according to the current operating frequency of the compressor in the current capacitance value range of the capacitance module, so as to detect the suspension position of the magnetic suspension bearing by using the first peak detection circuit and the second peak detection circuit after the capacitance value adjustment, and control the operation of the magnetic suspension system according to the detection result of the suspension position of the magnetic suspension bearing.

[0052] Specifically, see Figure 8 and Figure 9The example shows that when the magnetic suspension bearing is not suspended, the direct current voltage detected and output by the eddy current displacement sensor N is the minimum value Umin. The direct current voltage detected and output by the eddy current displacement sensor M is the maximum value Umax. The maximum value of the adjustable capacitor C1 is set by the difference between the maximum value Umax and the minimum value Umin, so that the direct current voltage value output by the peak detection circuit in the scheme of the application is the effective value. The maximum value of the adjustable capacitor is set according to the difference between Umax and Umin. The difference between Umax and Umin is the maximum displacement detected by the eddy current displacement sensor inside the compressor. For example, the difference U between Umax and Umin is 1V, and the capacitor C is charged. The smaller the capacity of the capacitor, the faster the charging and discharging speed. Similarly, the larger the capacity of the capacitor, the slower the charging and discharging speed. The charging and discharging speed affects the bandwidth of the output voltage, but it is not the faster the better. If the charging and discharging speed is too fast, the noise will be identified. If the charging and discharging speed is too slow, the bandwidth will be limited. Therefore, the difference U between Umax and Umin can be regarded as the bandwidth, and the detection period is fixed. Therefore, the C can be determined by the difference U between Umax and Umin, that is, the maximum value of the adjustable capacitor is determined.

[0053] When the magnetic suspension bearing is statically suspended and stable, the direct current voltage detected and output by the eddy current displacement sensor N is an intermediate value U between the minimum value Umin and the maximum value Umax. Since the air gap size inside different compressors is different, the output voltage value should be between 0 and 3V. The minimum value Umin and the maximum value Umax need to be determined in combination with the air gap size inside different compressors. By setting the adjustable capacitor C1, the sensitivity of the peak detection circuit can be adjusted according to the current operating frequency of the compressor.

[0054] Figure 10 The output waveform of the peak detection circuit in the application and the output waveform of the differential amplification circuit in the related scheme are compared. Figure 10 The value of the horizontal line is the direct current voltage value output after the sine wave passes through the two circuits. The actual value of the peak detection circuit is closer to the peak value. Figure 10 The waveform of the direct current voltage signal output after the same sine wave signal is processed by the differential amplification circuit and the peak detection circuit can be displayed. Compared with the direct current voltage signal detected by the peak detection circuit in the scheme of the application, the sensitivity of the magnetic suspension bearing control is increased. In the scheme of the application, the peak detection circuit is applied to the magnetic suspension bearing system, and the parameters of the peak detection circuit are adjusted according to the different operating frequencies of the compressor, so that the sensitivity of the magnetic suspension bearing control is more flexible.

[0055] In some embodiments, the current operating frequency of the compressor is within a preset frequency range of the compressor; the preset frequency range of the compressor includes n frequency intervals; the n frequency intervals include a first frequency interval, a second frequency interval to the nth frequency interval with sequentially increasing frequency values, where n is a positive integer. In step S230, based on the current operating frequency of the compressor, the current capacitance value of the capacitor module is adjusted within the current capacitance value range of the capacitor module to: use the first peak detection circuit and the second peak detection circuit after capacitance adjustment to detect the levitation position of the magnetic levitation bearing, and control the operation of the magnetic levitation system based on the detection result of the levitation position of the magnetic levitation bearing. The specific process is illustrated in the following exemplary description.

[0056] The following is combined Figure 3 The schematic diagram shown is an embodiment of the first process of adjusting the current capacitance value of the capacitor module within the current capacitance value range of the compressor according to the current operating frequency of the compressor in the method of the present invention. The specific process of adjusting the current capacitance value of the capacitor module within the current capacitance value range of the compressor according to the current operating frequency of the compressor in step S230 is further explained, including steps S310 to S320.

[0057] Step S310: Corresponding to the n frequency intervals in the preset frequency range of the compressor, the current capacitance range of the capacitor module is divided into n capacitance intervals. Specifically, the current capacitance range of the capacitor module is divided into n equal capacitance intervals. The n capacitance intervals include: a first capacitance interval, a second capacitance interval to the nth capacitance interval, with the capacitance values ​​decreasing sequentially. The first capacitance interval corresponds to the first frequency interval, the second capacitance interval corresponds to the second frequency interval, and so on, with the nth capacitance interval corresponding to the nth frequency interval.

[0058] Step S320: Based on the current operating frequency of the compressor within the preset frequency range of the compressor, adjust the current capacitance value of the capacitor module to the capacitance value within the capacitance range corresponding to that frequency range. Since the values ​​of Umax and Umin detected before each operation are different, the capacitance value of C1 is also different. Before each operation, the current capacitance value of C1 is divided into five equal parts corresponding to five operating frequencies.

[0059] Specifically, Figure 11 A flowchart illustrating the control of the peak detection circuit. (For example...) Figure 11 As shown, the control flow of the peak detection circuit includes:

[0060] Step 11, the bearing controller of the magnetic suspension bearing is running, detects the displacement of the magnetic suspension bearing and outputs the detected voltage signal, and then makes the magnetic suspension bearing float, and then steps 12 and 13 are executed. Among them, the bearing controller of the magnetic suspension bearing is powered on, and before the magnetic suspension bearing is floated, the displacement signal of the magnetic suspension bearing is detected and the detected voltage signal is outputted for value taking, that is, in the state of only power supply, the voltage signal is detected and the value is taken.

[0061] Step 12, the magnetic suspension system is running, and then step 14 is executed.

[0062] Step 13, according to the voltage signal outputted after detecting the displacement of the magnetic suspension bearing, the capacitance value of the adjustable capacitor C1 is outputted, and the capacitance value of the adjustable capacitor C1 is divided into five capacitance values from large to small in the internal of the monitoring control chip MCU, and then step 14 is executed.

[0063] The rated running frequency of the magnetic suspension unit is set to 500Hz in the MCU, the running is divided into five stages (0~100Hz, 100~200Hz, 200~300Hz, 300~400Hz, 400~500Hz), and the capacitance value of the adjustable capacitor C1 is divided into five equal parts, and the five stages of running frequency correspond to the five stages of capacitance value from large to small.

[0064] Step 14, according to the current running frequency of the compressor in the magnetic suspension system, determine the frequency range to which the current running frequency of the compressor belongs, and adjust the capacitance value of the adjustable capacitor C1 according to the different running frequencies of the compressor.

[0065] Specifically, the monitoring control chip MCU adjusts the capacitance value of the adjustable capacitor C1 according to the different running frequencies of the compressor while controlling the current running frequency of the compressor. According to the principle of the peak detection circuit of the eddy current displacement sensor, the voltage of the adjustable capacitor C1 is equal to the peak value of the input sine wave signal, and when the input sine wave signal is unchanged, according to the formula I=C·dv / dt, I is the fixed current of the operational amplifier, V represents the direct current voltage outputted by the peak detection circuit, and the capacitance value C of the adjustable capacitor C1 determines the charging and discharging speed of the adjustable capacitor C1 itself. The faster the speed, the faster the peak value of the sine wave signal can be detected and the more stable the output direct current voltage is. Therefore, when the magnetic suspension unit increases the frequency, the higher the current running frequency of the compressor is, the smaller the capacitance value C of the adjustable capacitor C1 is.

[0066] In some embodiments, the current operating frequency of the compressor is within a preset frequency range of the compressor; the preset frequency range of the compressor comprises n frequency intervals; the n frequency intervals comprise a first frequency interval, a second frequency interval to an n-th frequency interval in which the frequency values increase sequentially, and n is a positive integer. In step S230, the current capacitance value of the capacitance module is adjusted according to the current operating frequency of the compressor within the current capacitance range of the capacitance module, so as to detect the suspension position of the magnetic suspension bearing by using the first peak detection circuit and the second peak detection circuit after the capacitance value adjustment, and control the operation of the magnetic suspension system according to the detection result of the suspension position of the magnetic suspension bearing. For details, see the following exemplary description.

[0067] The following further illustrates the second process of adjusting the current capacitance value of the capacitance module according to the current operating frequency of the compressor within the current capacitance range of the capacitance module in the method of the present application by combining the above-mentioned embodiment of the method of the present application with the following embodiment of the method of the present application. Figure 4 The following further illustrates the second process of adjusting the current capacitance value of the capacitance module according to the current operating frequency of the compressor within the current capacitance range of the capacitance module in the method of the present application by combining the above-mentioned embodiment of the method of the present application with the following embodiment of the method of the present application.

[0068] In step S410, the maximum capacitance value of the capacitance module is determined within the current capacitance range of the capacitance module.

[0069] In step S420, the frequency interval in which the current operating frequency of the compressor is located in the preset frequency range of the compressor is determined, and the maximum capacitance value of the capacitance module is reduced by a set proportion corresponding to the position of the frequency interval in the preset frequency range of the compressor to obtain the adjusted capacitance value of the capacitance module; wherein the smaller the set proportion corresponding to the position of the frequency interval in the preset frequency range of the compressor, the smaller the adjusted capacitance value of the capacitance module; that is, the larger the current operating frequency of the compressor, the smaller the adjusted capacitance value of the capacitance module.

[0070] In step S430, the capacitance adjustment end of the capacitance module is controlled to take the adjusted capacitance value of the capacitance module as the current capacitance value of the capacitance module, so as to adjust the current capacitance value of the capacitance module.

[0071] Specifically, see Figure 11In the example shown, in step 14, if the current operating frequency f of the compressor satisfies 0Hz < f≤ 100Hz, the monitoring control chip MCU keeps the capacitance C of the output adjustable capacitor C1 as the set maximum value. If the current operating frequency f of the compressor satisfies 100Hz < f≤ 200Hz, the monitoring control chip MCU keeps the capacitance C of the output adjustable capacitor C1 as 4 / 5 times the set maximum value. If the current operating frequency f of the compressor satisfies 200Hz < f≤ 300Hz, the monitoring control chip MCU keeps the capacitance C of the output adjustable capacitor C1 as 3 / 5 times the set maximum value. If the current operating frequency f of the compressor satisfies 300Hz < f≤ 400Hz, the monitoring control chip MCU keeps the capacitance C of the output adjustable capacitor C1 as 2 / 5 times the set maximum value. If the current operating frequency f of the compressor satisfies 400Hz < f≤ 500Hz, the monitoring control chip MCU keeps the capacitance C of the output adjustable capacitor C1 as 1 / 5 times the set maximum value.

[0072] In some embodiments, the method for controlling the magnetic suspension system according to the scheme of the present application further comprises: a control process after adjusting the current capacitance of the capacitor module.

[0073] The following will be described in detail with reference to the accompanying drawings Figure 5 An embodiment flowchart of the control process after adjusting the current capacitance of the capacitor module in the method of the present application is shown in the accompanying drawings, which further illustrates the specific process of the control process after adjusting the current capacitance of the capacitor module, comprising: steps S510 to S530.

[0074] In step S510, after the magnetic suspension bearing is suspended, the peak value of the direct current voltage signal output by the first peak detection circuit after the sinusoidal wave signal detected by the first eddy current displacement sensor is adjusted, denoted as the third direct current voltage peak value, is obtained; and the peak value of the direct current voltage signal output by the second peak detection circuit after the sinusoidal wave signal detected by the second eddy current displacement sensor is adjusted, denoted as the fourth direct current voltage peak value, is obtained.

[0075] In step S520, the displacement signal of the magnetic suspension bearing is determined according to the third direct current voltage peak value and the fourth direct current voltage peak value.

[0076] In step S530, the operation of the magnetic suspension bearing is controlled according to the displacement signal of the magnetic suspension bearing, so as to realize the control of the magnetic suspension system.

[0077] Specifically, referring to Figure 9In the example shown, the sensitivity of the peak detection circuit can be adjusted by monitoring the control chip MCU to correspond to the parameters of the compressor in different frequency operating states. By automatically adjusting the parameters of the peak detection circuit, the data collected by the ADC module is compared, the displacement of the magnetic bearing is judged, and the response speed of the eddy current displacement sensor is automatically adjusted.

[0078] Figure 12 The effect curve of the signal peak detection sensitivity of the eddy current displacement sensor in the application is shown in the figure. Figure 12 In the figure, the X-axis is voltage, the Y-axis is displacement, a is the peak value of the direct current voltage signal output by the peak detection circuit, and b is the peak value of the direct current voltage signal output by the differential amplification circuit.

[0079] Figure 12 The relationship curve of voltage and displacement can be displayed, and the stronger the linearity, the higher the sensitivity of the eddy current displacement sensor. By comparing the two curves a and b, it can be clearly seen that in the same displacement state, the voltage value collected by the peak detection circuit in the application is smaller than that collected by the differential amplification circuit, and the collection result is more accurate than curve b. At the same time, since the voltage and displacement are inversely proportional, the greater the voltage, the smaller the displacement value detected by the displacement sensor. Under the automatic adjustment of the monitoring control chip MCU, the greater the displacement distance of the magnetic suspension bearing, the greater the difference between the two curves in collecting data, and the effect of the peak detection circuit in the application is obvious (such as more accurate detection precision), that is, the value output by the peak detection circuit is more accurate than that output by the differential amplification circuit, and is closer to the true value. The closer to the true value, the higher the sensitivity of the eddy current displacement sensor. For example: when the output voltage is measured as 1V, the displacement value detected by the peak value curve a of the direct current voltage signal output by the peak detection circuit is about 0.3um, and the displacement value detected by the peak value curve b of the direct current voltage signal output by the differential amplification circuit is about 1.3um. It can be seen that the detection precision of the peak value of the direct current voltage signal output by the peak detection circuit is more accurate. Compared with the peak value of the direct current voltage signal output by the differential amplification circuit, the peak detection circuit is more sensitive in the magnetic suspension system. According to the principle of the eddy current displacement sensor, the voltage and displacement are inversely proportional, and when the output voltage is the same, the greater the displacement, the more accurate the detection.

[0080] The use of the peak detection circuit has greatly improved the sensitivity of the eddy current displacement sensor, but different magnetic suspension compressors have different bearing suspension stabilities, and the magnetic suspension compressor will also cause different bearing gap stabilities after a long time of work. Therefore, as Figure 9As shown, after the position detection before each operation, the minimum value Umin and the maximum value Umax are updated before the stable suspension to set the maximum value of the adjustable capacitor C1, so as to ensure that the direct current voltage output by the peak detection circuit in the scheme of the application is the effective value. Since the internal space of the compressor may be affected by the temperature and bearing friction related factors after the operation of the compressor bearing, the gap between the bearing and the compressor is different before each operation, so that the Umax and Umin are updated before each suspension, and the C1 value is updated again.

[0081] In the scheme of the application, the peak detection circuit of the eddy current displacement sensor can more accurately identify the real effective value of the eddy current displacement sensor; and the parameters of the peak detection circuit are automatically adjusted according to the current operating frequency of the compressor, so as to more flexibly cope with the sensitivity of the magnetic suspension bearing control.

[0082] By adopting the technical scheme of the embodiment, one peak detection circuit is correspondingly arranged at the output end of each eddy current displacement sensor in the position detection of the magnetic suspension bearing, and an adjustable capacitor is arranged in the analog peak storage of each peak detection circuit. The upper and lower positions of the magnetic suspension bearing are detected before the operation of the magnetic suspension bearing after being powered on, the direct current voltages output by the peak detection circuits at the output ends of the two eddy current displacement sensors are obtained, the value of the adjustable capacitor is set according to the maximum value of the two direct current voltages, the value of the adjustable capacitor is divided into corresponding intervals corresponding to the frequency range of the current operating frequency of the compressor, and the value of the adjustable capacitor is adjusted according to the interval of the frequency range to which the current operating frequency of the compressor belongs after the magnetic suspension bearing is stably suspended and the magnetic suspension system is operated. Therefore, by adopting the peak detection circuit to process the sine wave signal generated by the eddy current displacement sensor to obtain the voltage signal of the shaft displacement of the magnetic suspension bearing in the position detection of the magnetic suspension bearing, and adjusting the parameters of the analog peak storage in the peak detection circuit according to the current operating frequency of the compressor, the actual value of the voltage signal of the shaft displacement output by the peak detection circuit is closer to the real value, so that the position detection of the magnetic suspension bearing is more accurate, and the sensitivity of the control of the magnetic suspension bearing is improved, and the stability of the magnetic suspension system is improved.

[0083] According to the embodiment of the application, a control device of a magnetic suspension system corresponding to the control method of the magnetic suspension system is also provided. Referring to Figure 6The structural schematic diagram of one embodiment of the device of the application is shown. The magnetic suspension system has a magnetic suspension bearing, of course, also has a bearing controller, that is, the magnetic suspension system has a magnetic suspension bearing and a bearing controller; the inner wall of the compressor inner cavity in the magnetic suspension system is symmetrically provided with a first eddy current displacement sensor and a second eddy current displacement sensor along the radial direction of the magnetic suspension bearing, such as distributing the first eddy current displacement sensor and the second eddy current displacement sensor above and below the magnetic suspension bearing, the first eddy current displacement sensor is such as an eddy current displacement sensor N, and the second eddy current displacement sensor is such as an eddy current displacement sensor M. Specifically, Figure 8 The distribution structure schematic diagram of the bearing and the eddy current displacement sensor in the application is shown. Figure 8 The positional relationship between the magnetic suspension bearing and the eddy current displacement sensor can be shown, and one eddy current displacement sensor is distributed above and below and left and right of the magnetic suspension bearing. Figure 8 Four direction eddy current displacement sensors are arranged in the application, so that the capacitance value of the adjustable capacitor C1 required in the scheme of the application can be obtained without using the floating shaft under the power-on condition of the magnetic suspension bearing.

[0084] A first peak detection circuit is arranged at the output end of the first eddy current displacement sensor, and a second peak detection circuit is arranged at the output end of the second eddy current displacement sensor; specifically, a first peak detection circuit is arranged between the output end of the first eddy current displacement sensor and the bearing controller; a second peak detection circuit is arranged between the output end of the second eddy current displacement sensor and the bearing controller; the analog peak storage in the first peak detection circuit and the analog peak storage in the second peak detection circuit both adopt a capacitor module with adjustable capacitance value, such as an adjustable capacitor C1; the first peak detection circuit and the second peak detection circuit have the same structure. Specifically, Figure 9 The structural schematic diagram of the peak detection circuit in the application is shown. As Figure 9 As shown, the peak detection circuit comprises an operational amplifier U1, an operational amplifier U2, a diode D1, a diode D2, an adjustable capacitor C1, a resistor R1, a resistor R2, an ADC module, and a monitoring control chip MCU. Among them, the adjustable capacitor C1 is used as an analog peak storage. The diode D1 and the diode D2 are used as one-way power switches. The resistor R1 is used as an input-output buffer isolation device. In Figure 9In the shown example, the sine wave signal output by the eddy current displacement sensor N is input to the in-phase input terminal of the operational amplifier U1; the anti-phase input terminal of the operational amplifier U1 is connected to the anti-phase input terminal of the operational amplifier U2 through the resistor R1. The output terminal of the operational amplifier U1 is connected to the cathode of the diode D2, and the anode of the diode D2 is connected to the common terminal of the anti-phase input terminal of the operational amplifier U1 and the resistor R1. The output terminal of the operational amplifier U1 is connected to the anode of the diode D1; the cathode of the diode D1 is connected to the in-phase input terminal of the operational amplifier U2. The cathode of the diode D1 and the common terminal of the operational amplifier U2 are connected to the ground through the parallelly connected adjustable capacitor C1 and resistor R2. The output terminal of the operational amplifier U2 outputs a direct current voltage signal Un as the displacement collection signal of the eddy current displacement sensor N. The output terminal of the operational amplifier U2 is input to the input terminal of the monitoring control chip MCU after data collection by the ADC module. The output terminal of the monitoring control chip MCU outputs a control signal to the adjustment terminal of the adjustable capacitor C1.

[0085] In the scheme of the present application, as shown in the figure, Figure 6 The control device of the magnetic suspension system comprises an acquisition unit 102 and a control unit 104.

[0086] The acquisition unit 102 is configured to acquire the peak value of the direct current voltage signal output by the first eddy current displacement sensor after the sine wave signal detected by the first eddy current displacement sensor is input to the first peak detection circuit, which is recorded as the first direct current voltage peak value; and acquire the peak value of the direct current voltage signal output by the second eddy current displacement sensor after the sine wave signal detected by the second eddy current displacement sensor is input to the second peak detection circuit, which is recorded as the second direct current voltage peak value. The first direct current voltage peak value is the minimum value Umin, and the second direct current voltage peak value is the maximum value Umax. The specific functions and processes of the acquisition unit 102 are described in step S110.

[0087] The acquisition unit 102 is further configured to acquire the operating frequency of the compressor in the magnetic suspension system after the magnetic suspension bearing is suspended, which is recorded as the current operating frequency of the compressor. The specific functions and processes of the acquisition unit 102 are also described in step S120.

[0088] The control unit 104 is configured to adjust the current capacitance value of the capacitor module according to the first direct current voltage peak value and the second direct current voltage peak value, and the current operating frequency of the compressor in the magnetic suspension system, so as to detect the suspension position of the magnetic suspension bearing by using the first peak detection circuit and the second peak detection circuit after the capacitance value adjustment, and control the operation of the magnetic suspension system according to the detection result of the suspension position of the magnetic suspension bearing. The specific functions and processes of the control unit 104 are described in step S130.

[0089] The peak detection circuit of the eddy current displacement sensor provided by the scheme can accurately identify the peak value of the sine wave signal generated by the eddy current displacement sensor, so that the actual value of the sine wave signal generated by the eddy current displacement sensor is infinitely close to the true value (i.e. the peak value of the sine wave signal), thereby outputting an accurate direct current voltage signal, and the problem of low sensitivity of the differential amplification circuit in identifying the sine wave signal generated by the eddy current displacement sensor can be solved, and the sensitivity of the magnetic suspension bearing control is improved. Moreover, based on different operating frequencies of the magnetic suspension bearing, the parameters of the peak detection circuit in the scheme are automatically adjusted according to the corresponding frequency, that is, the parameters of the corresponding peak detection circuit are automatically adjusted according to the different operating frequencies of the magnetic suspension bearing, so that the parameters of the peak detection circuit under different operating frequencies of the magnetic suspension bearing are adapted, the parameters of the corresponding peak detection circuit can be automatically identified and adjusted under different rotating speeds, and the accuracy of the magnetic suspension bearing control is further improved.

[0090] In some embodiments, the control unit 104 adjusts the current capacitance value of the capacitance module according to the first direct current voltage peak value and the second direct current voltage peak value and the current operating frequency of the compressor in the magnetic suspension system, so as to detect the suspension position of the magnetic suspension bearing by using the first peak detection circuit and the second peak detection circuit after the capacitance value adjustment, and control the operation of the magnetic suspension system according to the detection result of the suspension position of the magnetic suspension bearing, including:

[0091] The control unit 104 is specifically further configured to determine the current capacitance value range of the capacitance module according to the first direct current voltage peak value and the second direct current voltage peak value. The specific functions and processes of the control unit 104 are also described in step S210.

[0092] The control unit 104 is specifically further configured to adjust the current capacitance value of the capacitance module within the current capacitance value range of the capacitance module according to the current operating frequency of the compressor after the magnetic suspension bearing is suspended, so as to detect the suspension position of the magnetic suspension bearing by using the first peak detection circuit and the second peak detection circuit after the capacitance value adjustment, and control the operation of the magnetic suspension system according to the detection result of the suspension position of the magnetic suspension bearing. The specific functions and processes of the control unit 104 are also described in step S220.

[0093] Specifically, refer to Figure 8 and Figure 9The example shows that when the magnetic suspension bearing is not suspended, the direct current voltage detected and output by the eddy current displacement sensor N is the minimum value Umin. The direct current voltage detected and output by the eddy current displacement sensor M is the maximum value Umax. The maximum capacitance of the adjustable capacitor C1 is set by the difference between the maximum value Umax and the minimum value Umin, so that the direct current voltage value output by the peak detection circuit in the scheme of the application is the effective value. When the magnetic suspension bearing is statically suspended and stable, the direct current voltage detected and output by the eddy current displacement sensor N is the intermediate value U between the minimum value Umin and the maximum value Umax. Since the air gap sizes in different compressors are different, the output voltage value should be between 0 and 3V; and the minimum value Umin and the maximum value Umax need to be determined in combination with the air gap sizes in different compressors. By setting the adjustable capacitor C1, the sensitivity of the peak detection circuit can be adjusted according to the current operating frequency of the compressor.

[0094] Figure 10 The output waveform of the peak detection circuit in the application and the output waveform of the differential amplification circuit in the related scheme are compared. Figure 10 The output waveform of the peak detection circuit in the application and the output waveform of the differential amplification circuit in the related scheme are compared. Figure 10 The output waveform of the peak detection circuit in the application and the output waveform of the differential amplification circuit in the related scheme are compared.

[0095] In some embodiments, the current operating frequency of the compressor is within a preset frequency range of the compressor, the preset frequency range of the compressor includes n frequency intervals, the n frequency intervals include a first frequency interval, a second frequency interval to an n-th frequency interval, and the frequency value of each frequency interval is sequentially increased, and n is a positive integer. The control unit 104 adjusts the current capacitance of the capacitor module according to the current operating frequency of the compressor within the current capacitance range of the capacitor module, so as to detect the suspension position of the magnetic suspension bearing by using the first peak detection circuit and the second peak detection circuit after the capacitance adjustment, and control the operation of the magnetic suspension system according to the detection result of the suspension position of the magnetic suspension bearing, including:

[0096] The control unit 104 is further configured to divide the current capacitance range of the capacitor module into n capacitance intervals corresponding to n frequency intervals in the preset frequency range of the compressor, specifically, to divide the current capacitance range of the capacitor module into n equal capacitance intervals; the n capacitance intervals include a first capacitance interval, a second capacitance interval, and an n-th capacitance interval in which the capacitance decreases successively; the first capacitance interval corresponds to the first frequency interval, the second capacitance interval corresponds to the second frequency interval, and so on, and the n-th capacitance interval corresponds to the n-th frequency interval. The specific functions and processes of the control unit 104 are also described in step S310.

[0097] The control unit 104 is further configured to adjust the current capacitance of the capacitor module to the capacitance in the capacitance interval corresponding to the frequency interval in which the current operating frequency of the compressor is located.

[0098] Specifically, Figure 11 The flowchart for controlling the peak detection circuit is shown in FIG. 6. As shown in FIG. 6, the flowchart for controlling the peak detection circuit includes the following steps: Figure 11 The flowchart for controlling the peak detection circuit is shown in FIG. 6. As shown in FIG. 6, the flowchart for controlling the peak detection circuit includes the following steps:

[0099] Step 11: The bearing controller of the magnetic suspension bearing operates, detects the displacement of the magnetic suspension bearing, and outputs a detected voltage signal, and then makes the magnetic suspension bearing float, and then executes steps 12 and 13.

[0100] Step 12: The magnetic suspension system operates, and then executes step 14.

[0101] Step 13: According to the voltage signal output after detecting the displacement of the magnetic suspension bearing, the capacitance of the adjustable capacitor C1 is output, and the capacitance of the adjustable capacitor C1 is divided into five capacitances from large to small in the internal monitoring control chip MCU, and then step 14 is executed.

[0102] The rated operating frequency of the magnetic suspension unit is set to 500 Hz in the MCU, the operation is divided into five stages (0~100Hz, 100~200Hz, 200~300Hz, 300~400Hz, 400~500Hz), and the capacitance of the adjustable capacitor C1 is divided into five equal parts, and the capacitance from large to small corresponds to the five stages of operating frequency.

[0103] Step 14: According to the current operating frequency of the compressor in the magnetic suspension system, determine the frequency range to which the current operating frequency of the compressor belongs, and adjust the capacitance of the adjustable capacitor C1 according to the different operating frequencies of the compressor.

[0104] Specifically, the monitoring control chip MCU adjusts the capacitance of the adjustable capacitor C1 according to different operating frequencies of the compressor while controlling the current operating frequency of the compressor. According to the principle of the peak detection circuit of the eddy current displacement sensor, the voltage of the adjustable capacitor C1 is equal to the peak value of the input sine wave signal, and when the input sine wave signal is unchanged, according to the formula I = C dv / dt, I is the fixed current of the operational amplifier, the capacitance C of the adjustable capacitor C1 determines the charging and discharging speed of the adjustable capacitor C1 itself, the faster the speed, the more the peak value of the sine wave signal can be detected and the more stable the output direct current voltage is. Therefore, when the magnetic suspension unit increases the frequency, the higher the current operating frequency of the compressor is, the smaller the capacitance C of the corresponding adjustable capacitor C1 is.

[0105] In some embodiments, the current operating frequency of the compressor is within a preset frequency range of the compressor, and the preset frequency range of the compressor includes n frequency intervals, the n frequency intervals include a first frequency interval, a second frequency interval to an n frequency interval in which the frequency values increase sequentially, and n is a positive integer. The control unit 104 adjusts the current capacitance of the capacitor module according to the current operating frequency of the compressor within the current capacitance range of the capacitor module, so as to detect the suspension position of the magnetic suspension bearing by using the first peak detection circuit and the second peak detection circuit after the capacitance adjustment, and control the operation of the magnetic suspension system according to the detection result of the suspension position of the magnetic suspension bearing, and further includes:

[0106] The control unit 104 is specifically further configured to determine the maximum capacitance of the capacitor module within the current capacitance range of the capacitor module. The specific functions and processes of the control unit 104 are also described in step S410.

[0107] The control unit 104 is specifically further configured to determine the frequency interval in which the current operating frequency of the compressor is located in the preset frequency range of the compressor, and to reduce the maximum capacitance of the capacitor module by a set proportion corresponding to the position of the frequency interval in the preset frequency range of the compressor to obtain the adjusted capacitance of the capacitor module, wherein the later the position of the frequency interval in the preset frequency range of the compressor is, the smaller the set proportion corresponding to the position is, and the smaller the obtained adjusted capacitance of the capacitor module is. That is, the larger the current operating frequency of the compressor is, the smaller the obtained adjusted capacitance of the capacitor module is. The specific functions and processes of the control unit 104 are also described in step S420.

[0108] The control unit 104 is further configured to control the capacitance adjustment terminal of the capacitor module, so as to use the adjusted capacitance value of the capacitor module as the current capacitance value of the capacitor module, thereby adjusting the current capacitance value of the capacitor module. The specific functions and processing of the control unit 104 are further described in step S430.

[0109] Specifically, see Figure 11 In the example shown, in step 14, if the current operating frequency f of the compressor satisfies 0Hz < f ≤ 100Hz, the monitoring and control chip MCU maintains the capacitance C of the adjustable output capacitor C1 at the set maximum value. If the current operating frequency f of the compressor satisfies 100Hz < f ≤ 200Hz, the monitoring and control chip MCU maintains the capacitance C of the adjustable output capacitor C1 at 4 / 5 times the set maximum value. If the current operating frequency f of the compressor satisfies 200Hz < f ≤ 300Hz, the monitoring and control chip MCU maintains the capacitance C of the adjustable output capacitor C1 at 3 / 5 times the set maximum value. If the current operating frequency f of the compressor satisfies 300Hz < f ≤ 400Hz, the monitoring and control chip MCU maintains the capacitance C of the adjustable output capacitor C1 at 2 / 5 times the set maximum value. If the current operating frequency f of the compressor satisfies 400Hz < f ≤ 500Hz, the monitoring and control chip MCU maintains the capacitance C of the adjustable output capacitor C1 at 1 / 5 times the set maximum value.

[0110] In some embodiments, the control method for the magnetic levitation system described in the present invention further includes: a control process after adjusting the current capacitance value of the capacitor module, as detailed below:

[0111] The acquisition unit 102 is further configured to, after the magnetic levitation bearing is levitated and the current capacitance value of the capacitor module is adjusted, acquire the peak value of the DC voltage signal output from the sinusoidal signal detected by the first eddy current displacement sensor after passing through the first peak detection circuit, and record it as the third DC voltage peak value; and acquire the peak value of the DC voltage signal output from the sinusoidal signal detected by the second eddy current displacement sensor after passing through the second peak detection circuit, and record it as the fourth DC voltage peak value. The specific functions and processing of this acquisition unit 102 are further described in step S510.

[0112] The control unit 104 is further configured to determine the displacement signal of the magnetic levitation bearing based on the third DC voltage peak value and the fourth DC voltage peak value. The specific functions and processing of the control unit 104 are further described in step S520.

[0113] The control unit 104 is further configured to control the operation of the magnetic suspension bearing according to the displacement signal of the magnetic suspension bearing to achieve control of the magnetic suspension system. The specific functions and processes of the control unit 104 are also described in step S530.

[0114] Specifically, referring to Figure 9 In the example shown, the monitoring control chip MCU can adjust the sensitivity of the peak detection circuit to correspond to the parameters in different frequency working states of the compressor. By automatically adjusting the parameters of the peak detection circuit, comparing the values of the data collected by the ADC module, judging the displacement of the magnetic suspension bearing, and then automatically adjusting the response speed of the eddy current displacement sensor.

[0115] Figure 12 The effect curve diagram of the signal peak detection sensitivity of the eddy current displacement sensor in the application. Figure 12 In the application, the X-axis is the voltage, the Y-axis is the displacement, a is the peak value of the direct current voltage signal output by the peak detection circuit, and b is the peak value of the direct current voltage signal output by the differential amplification circuit.

[0116] Figure 12 The relationship curve of voltage and displacement can be displayed. The stronger the linearity, the higher the sensitivity of the eddy current displacement sensor. By comparing the two curves a and b, it can be clearly seen that in the same displacement state, the voltage value collected by the peak detection circuit in the application is smaller than that collected by the differential amplification circuit, and the collection result is more accurate than curve b. At the same time, since the voltage and displacement are inversely proportional, the greater the voltage, the smaller the displacement value detected by the displacement sensor. Under the automatic adjustment of the monitoring control chip MCU, the greater the displacement distance of the magnetic suspension bearing, the greater the difference between the two curves in collecting data, and the effect of using the peak detection circuit in the application is obvious, that is, the output value of the peak detection circuit is more accurate than that of the differential amplification circuit, and is closer to the true value. The closer to the true value, the higher the sensitivity of the eddy current displacement sensor. For example: when the output voltage is measured as 1V, the displacement value detected by the peak value curve a of the direct current voltage signal output by the peak detection circuit is about 0.3um, and the displacement value detected by the peak value curve b of the direct current voltage signal output by the differential amplification circuit is about 1.3um. It can be seen that the detection accuracy of the peak value of the direct current voltage signal output by the peak detection circuit is more accurate. Compared with the same voltage, the peak detection circuit in the magnetic suspension system is more sensitive.

[0117] The use of the peak detection circuit has greatly improved the sensitivity of the eddy current displacement sensor, but different magnetic suspension compressors have different bearing suspension stabilities, and the magnetic suspension compressor will also cause different bearing gap stabilities after a long time of work. Therefore, as Figure 9As shown, after position detection before each operation, the minimum value Umin and the maximum value Umax are updated before stable suspension to set the maximum value of the adjustable capacitor C1, so that the direct current voltage output by the peak detection circuit in the scheme of the application is the effective value. In the scheme of the application, the peak detection circuit of the eddy current displacement sensor can more accurately identify the real effective value of the eddy current displacement sensor; and the parameters of the peak detection circuit are automatically adjusted according to the current operating frequency of the compressor, so that the sensitivity of the magnetic suspension bearing control can be more flexibly coped with.

[0118] Since the processing and functions realized by the device of the embodiment are basically corresponding to the embodiments, principles and examples of the foregoing method, the description of the embodiment will not be described in detail, and the related description in the foregoing embodiments can be referred to, and will not be described here.

[0119] By adopting the technical scheme of the application, one eddy current displacement sensor is arranged above and below the magnetic suspension bearing in the position detection of the magnetic suspension bearing, and one peak detection circuit is correspondingly arranged at the output end of each eddy current displacement sensor; the analog peak storage in each peak detection circuit adopts an adjustable capacitor; the up and down positions of the magnetic suspension bearing are detected before the magnetic suspension bearing is powered on and operated, the direct current voltages output by the peak detection circuits at the output ends of the two eddy current displacement sensors are obtained, the capacitance value of the adjustable capacitor is set according to the maximum value of the two direct current voltages; the capacitance value of the adjustable capacitor set is divided into corresponding intervals corresponding to the frequency range of the current operating frequency of the compressor; after the magnetic suspension bearing is stably suspended, the current operating frequency of the compressor is obtained under the operation of the magnetic suspension system, the interval corresponding to the capacitance value of the adjustable capacitor is adjusted according to the interval of the frequency range to which the current operating frequency of the compressor belongs, so that the actual value of the sine wave signal generated by the eddy current displacement sensor is infinitely close to the real value (i.e. the peak value of the sine wave signal), thereby outputting an accurate direct current voltage signal.

[0120] According to the embodiment of the application, a magnetic suspension system corresponding to the control device of the magnetic suspension system is also provided. The magnetic suspension system can include the control device of the magnetic suspension system described above.

[0121] Since the processing and functions realized by the magnetic suspension system of the embodiment are basically corresponding to the embodiments, principles and examples of the foregoing device, the description of the embodiment will not be described in detail, and the related description in the foregoing embodiments can be referred to, and will not be described here.

[0122] The technical scheme of the present application is characterized in that: in the position detection of the magnetic suspension bearing, one eddy current displacement sensor is distributed above and below the magnetic suspension bearing respectively, and one peak detection circuit is correspondingly arranged at the output end of each eddy current displacement sensor; the analog peak storage in each peak detection circuit adopts an adjustable capacitor; before the magnetic suspension bearing is powered on and runs, the up and down positions of the magnetic suspension bearing are detected to obtain the direct current voltage output by the peak detection circuit at the output end of the two eddy current displacement sensors, and the capacitance value of the adjustable capacitor is set according to the maximum value of the two direct current voltages; the set capacitance value of the adjustable capacitor is divided into corresponding intervals corresponding to the interval of the frequency range of the current running frequency of the compressor; after the magnetic suspension bearing is stably suspended, the current running frequency of the compressor is obtained under the condition that the magnetic suspension system is running, and the interval corresponding to the capacitance value of the adjustable capacitor is adjusted according to the interval of the frequency range to which the current running frequency of the compressor belongs, so that the parameters of the corresponding peak detection circuit can be automatically identified and adjusted under different rotating speeds, and the precision of the magnetic suspension bearing control is further improved.

[0123] According to the embodiment of the present application, a storage medium corresponding to the control method of the magnetic suspension system is also provided, and the storage medium comprises a stored program, wherein when the program is executed, the device where the storage medium is located performs the control method of the magnetic suspension system.

[0124] Since the processing and functions realized by the storage medium of the present embodiment are basically corresponding to the embodiments, principles and examples of the foregoing method, the description of the present embodiment will not be described in detail, and the relevant description in the foregoing embodiments can be referred to, which will not be described herein.

[0125] The technical scheme of the present application is characterized in that: in the position detection of the magnetic suspension bearing, one eddy current displacement sensor is distributed above and below the magnetic suspension bearing respectively, and one peak detection circuit is correspondingly arranged at the output end of each eddy current displacement sensor; the analog peak storage in each peak detection circuit adopts an adjustable capacitor; before the magnetic suspension bearing is powered on and runs, the up and down positions of the magnetic suspension bearing are detected to obtain the direct current voltage output by the peak detection circuit at the output end of the two eddy current displacement sensors, and the capacitance value of the adjustable capacitor is set according to the maximum value of the two direct current voltages; the set capacitance value of the adjustable capacitor is divided into corresponding intervals corresponding to the interval of the frequency range of the current running frequency of the compressor; after the magnetic suspension bearing is stably suspended, the current running frequency of the compressor is obtained under the condition that the magnetic suspension system is running, and the interval corresponding to the capacitance value of the adjustable capacitor is adjusted according to the interval of the frequency range to which the current running frequency of the compressor belongs, so that the parameters of the corresponding peak detection circuit can be automatically identified and adjusted under different rotating speeds, and the precision of the magnetic suspension bearing control is further improved.

[0126] In summary, those skilled in the art can easily understand that the above advantageous modes can be freely combined and superimposed without conflict.

[0127] The above merely provides the embodiments of the present application but are not intended to limit the present application. Changes can be made for the present application by those skilled in the art without departing from the spirit and principle of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall fall within the scope of claims of the present application.

Claims

1. A control method for a magnetic levitation system, characterized in that, The magnetic levitation system includes a magnetic levitation bearing. A first eddy current displacement sensor and a second eddy current displacement sensor are symmetrically arranged on the inner wall of the compressor's internal cavity, along the radial direction of the magnetic levitation bearing. A first peak detection circuit is provided at the output terminal of the first eddy current displacement sensor, and a second peak detection circuit is provided at the output terminal of the second eddy current displacement sensor. Both the analog peak memory in the first peak detection circuit and the analog peak memory in the second peak detection circuit utilize capacitor modules with adjustable capacitance. The control method for the magnetic levitation system includes: Before the magnetic levitation bearing is levitated after being powered on, the peak value of the DC voltage signal output by the sinusoidal signal detected by the first eddy current displacement sensor after passing through the first peak detection circuit is obtained and recorded as the first DC voltage peak value; and the peak value of the DC voltage signal output by the sinusoidal signal detected by the second eddy current displacement sensor after passing through the second peak detection circuit is obtained and recorded as the second DC voltage peak value. After the magnetic bearing is levitated, the operating frequency of the compressor in the magnetic levitation system is obtained and recorded as the current operating frequency of the compressor. The current capacitance value of the capacitor module is adjusted based on the first DC voltage peak value, the second DC voltage peak value, and the current operating frequency of the compressor in the magnetic levitation system.

2. The control method for the magnetic levitation system according to claim 1, characterized in that, Based on the first DC voltage peak value, the second DC voltage peak value, and the current operating frequency of the compressor in the magnetic levitation system, the current capacitance value of the capacitor module is adjusted, including: The current capacitance range of the capacitor module is determined based on the first DC voltage peak value and the second DC voltage peak value. After the magnetic levitation bearing is levitated, the current capacitance value of the capacitor module is adjusted within the current capacitance value range of the compressor, based on the current operating frequency of the compressor.

3. The control method for the magnetic levitation system according to claim 2, characterized in that, The current operating frequency of the compressor is within the preset frequency range of the compressor; The preset frequency range of the compressor includes: n frequency intervals; the n frequency intervals include: a first frequency interval, a second frequency interval to the nth frequency interval with the frequency values ​​increasing sequentially, where n is a positive integer; Based on the compressor's current operating frequency, and within the current capacitance range of the capacitor module, the current capacitance value of the capacitor module is adjusted, including: Corresponding to the n frequency intervals in the preset frequency range of the compressor, the current capacitance value range of the capacitor module is divided into n capacitance value intervals; the n capacitance value intervals include: a first capacitance value interval, a second capacitance value interval to the nth capacitance value interval with the capacitance value decreasing sequentially; wherein, the first capacitance value interval corresponds to the first frequency interval; Based on the current operating frequency of the compressor, which falls within the preset frequency range of the compressor, the current capacitance value of the capacitor module is adjusted to the capacitance value within the capacitance range corresponding to that frequency range.

4. The control method for the magnetic levitation system according to claim 2, characterized in that, The current operating frequency of the compressor is within the preset frequency range of the compressor; The preset frequency range of the compressor includes: n frequency intervals; the n frequency intervals include: a first frequency interval, a second frequency interval to the nth frequency interval with the frequency values ​​increasing sequentially, where n is a positive integer; Based on the compressor's current operating frequency, and within the current capacitance range of the capacitor module, adjusting the current capacitance value of the capacitor module further includes: Within the current capacitance range of the capacitor module, determine the maximum capacitance value of the capacitor module; The current operating frequency of the compressor is determined to be within the frequency range of the compressor's preset frequency range. Based on the position of this frequency range within the compressor's preset frequency range, the maximum capacitance value of the capacitor module is reduced by a set ratio corresponding to that position to obtain the adjustable capacitance value of the capacitor module. The higher the current operating frequency of the compressor, the smaller the adjusted capacitance value of the capacitor module. The capacitance adjustment terminal of the capacitor module is controlled so that the adjusted capacitance value of the capacitor module is used as the current capacitance value of the capacitor module, thereby realizing the adjustment of the current capacitance value of the capacitor module.

5. The control method for the magnetic levitation system according to any one of claims 1 to 4, characterized in that, Also includes: After adjusting the current capacitance value of the capacitor module, the peak value of the DC voltage signal output by the sinusoidal signal detected by the first eddy current displacement sensor after passing through the first peak detection circuit is obtained and recorded as the third DC voltage peak value; and the peak value of the DC voltage signal output by the sinusoidal signal detected by the second eddy current displacement sensor after passing through the second peak detection circuit is obtained and recorded as the fourth DC voltage peak value. The displacement signal of the magnetic levitation bearing is determined based on the third DC voltage peak value and the fourth DC voltage peak value. The operation of the magnetic levitation bearing is controlled based on the displacement signal of the magnetic levitation bearing, so as to achieve control of the magnetic levitation system.

6. A control device for a magnetic levitation system, characterized in that, The magnetic levitation system includes a magnetic levitation bearing. A first eddy current displacement sensor and a second eddy current displacement sensor are symmetrically arranged on the inner wall of the compressor's internal cavity, along the radial direction of the magnetic levitation bearing. A first peak detection circuit is provided at the output terminal of the first eddy current displacement sensor, and a second peak detection circuit is provided at the output terminal of the second eddy current displacement sensor. Both the analog peak memory in the first peak detection circuit and the analog peak memory in the second peak detection circuit utilize capacitor modules with adjustable capacitance. The control device for the magnetic levitation system includes: The acquisition unit is configured to acquire the peak value of the DC voltage signal output by the sinusoidal signal detected by the first eddy current displacement sensor after passing through the first peak detection circuit, and record it as the first DC voltage peak value; and acquire the peak value of the DC voltage signal output by the sinusoidal signal detected by the second eddy current displacement sensor after passing through the second peak detection circuit, and record it as the second DC voltage peak value. The acquisition unit is further configured to acquire the operating frequency of the compressor in the magnetic levitation system after the magnetic levitation bearing is levitated, and record it as the current operating frequency of the compressor. The control unit is configured to adjust the current capacitance value of the capacitor module based on the first DC voltage peak value, the second DC voltage peak value, and the current operating frequency of the compressor in the magnetic levitation system.

7. The control device for the magnetic levitation system according to claim 6, characterized in that, The control unit adjusts the current capacitance value of the capacitor module based on the first DC voltage peak value, the second DC voltage peak value, and the current operating frequency of the compressor in the magnetic levitation system, including: The current capacitance range of the capacitor module is determined based on the first DC voltage peak value and the second DC voltage peak value. After the magnetic levitation bearing is levitated, the current capacitance value of the capacitor module is adjusted within the current capacitance value range of the compressor, based on the current operating frequency of the compressor.

8. The control device for the magnetic levitation system according to claim 7, characterized in that, The current operating frequency of the compressor is within the preset frequency range of the compressor; The preset frequency range of the compressor includes: n frequency intervals; the n frequency intervals include: a first frequency interval, a second frequency interval to the nth frequency interval with the frequency values ​​increasing sequentially, where n is a positive integer; The control unit adjusts the current capacitance value of the capacitor module within the current capacitance value range of the compressor, based on the compressor's current operating frequency, including: Corresponding to the n frequency intervals in the preset frequency range of the compressor, the current capacitance value range of the capacitor module is divided into n capacitance value intervals; the n capacitance value intervals include: a first capacitance value interval, a second capacitance value interval to the nth capacitance value interval with the capacitance value decreasing sequentially; wherein, the first capacitance value interval corresponds to the first frequency interval; Based on the current operating frequency of the compressor, which falls within the preset frequency range of the compressor, the current capacitance value of the capacitor module is adjusted to the capacitance value within the capacitance range corresponding to that frequency range.

9. A magnetic levitation system, characterized in that, include: The control device for the magnetic levitation system as described in any one of claims 6 to 8.

10. A storage medium, characterized in that, The storage medium includes a stored program, wherein, when the program is executed, the device containing the storage medium is controlled to perform the control method of the magnetic levitation system according to any one of claims 1 to 5.

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