Compressor control method, control system and outdoor unit

Abstract

The application relates to a compressor control method, a control system and an outdoor unit. The method comprises the following steps: S1, acquiring three-phase currents of a compressor and a direct-current bus voltage, and converting the three-phase currents to obtain q-axis and d-axis currents; S2, constructing a first current loop and a second current loop corresponding to the compressor; S3, confirming whether a real-time rotating speed of the compressor is within a first preset range of a preset rotating speed; if yes, executing S4, otherwise executing S6; S4, compensating speed loop output of the compressor within a preset time length before and after a current zero point of the compressor; S5, predicting and reconstructing the direct-current bus voltage of the compressor, generating a control signal corresponding to the compressor according to the reconstructed direct-current bus voltage of the compressor, and executing S7; S6, generating the control signal corresponding to the compressor according to the direct-current bus voltage of the compressor, and executing S7; and S7, controlling a driving circuit of the compressor through the control signal. The application can reduce three-phase current fluctuation of the compressor during operation and improve operation efficiency of the compressor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of compressor control, in particular to a compressor control method, a control system and an outdoor unit. BACKGROUND

[0002] Currently, in the related technology of heating, ventilation and air conditioning equipment, the compressor driving part of the heating, ventilation and air conditioning equipment gradually adopts a scheme of replacing electrolytic capacitor. The electrolytic capacitor is small in volume and low in cost, which meets the technical development needs of the heating, ventilation and air conditioning equipment. However, due to its low storage capacity, the output DC bus voltage fluctuates greatly during the operation of the heating, ventilation and air conditioning compressor, which leads to unstable control of the three-phase current output to the compressor in the case of high-frequency operation of the compressor, poor waveform quality and great control difficulty. Therefore, after the outdoor driving control board device is changed to the electrolytic capacitor, when the DC bus voltage fluctuates too much, the three-phase current output by the driving control board device has large output beat frequency in the case of high-frequency operation of the compressor, thereby causing the problem of waveform jitter during the operation of the compressor. SUMMARY

[0003] The technical problem to be solved by the present application is to provide a compressor control method, a control system and an outdoor unit to solve the above technical defects of the prior art.

[0004] The technical scheme adopted by the present application to solve the technical problem is: a compressor control method is constructed, comprising the following steps:

[0005] S1, acquiring the three-phase current of the compressor and the DC bus voltage of the compressor, and converting the three-phase current of the compressor to obtain q-axis current and d-axis current;

[0006] S2, constructing a first current loop and a second current loop corresponding to the compressor, wherein the q-axis current is the feedback input of the first current loop, and the speed loop output of the compressor is the reference input of the first current loop, and the d-axis current is the feedback input of the second current loop corresponding to the compressor, and a preset value is the reference input of the second current loop;

[0007] S3, acquiring the real-time speed of the compressor, and confirming whether the real-time speed of the compressor is within a first preset range of a preset speed, wherein the compressor will have current jitter when the preset speed; if yes, step S4 is executed, otherwise step S6 is executed;

[0008] S4, compensating the speed loop output of the compressor within a preset time length before and after the current zero point of the compressor, and taking the compensated speed loop output as the reference input of the first current loop;

[0009] S5, predicting and reconstructing the DC bus voltage of the compressor, and generating the control signal corresponding to the compressor by SVPWM modulation according to the reconstructed DC bus voltage of the compressor, the output of the first current loop and the output of the second current loop, and performing step S7;

[0010] S6, generating the control signal corresponding to the compressor by SVPWM modulation according to the DC bus voltage of the compressor, the output of the first current loop and the output of the second current loop, and performing step S7;

[0011] S7, controlling the driving circuit of the compressor by the control signal.

[0012] Preferably, in the compressor control method embodiment provided by the application, the preset value is zero.

[0013] Preferably, in the compressor control method embodiment provided by the application, in the step S4, the speed loop output of the compressor is compensated within the preset time length before and after the current zero-crossing point of the compressor, comprising:

[0014] Obtaining the product of the speed loop output of the compressor and the compensation coefficient to obtain the compensated speed loop output, wherein the compensation coefficient is a constant not equal to zero.

[0015] Preferably, in the compressor control method embodiment provided by the application, in the step S4, the speed loop output of the compressor is compensated within the preset time length before and after the current zero-crossing point of the compressor, comprising:

[0016] Obtaining the current zero-crossing point of the compressor, obtaining a preset time length with the first time point before the current zero-crossing point as the starting point and the second time point after the current zero-crossing point as the ending point, and compensating the speed loop output of the compressor within the preset time length.

[0017] Preferably, in the compressor control method embodiment provided by the application, the first time point is a time point before the current zero-crossing point with the current phase angle between-15 degrees and-45 degrees; and / or the second time point is a time point after the current zero-crossing point with the current phase angle between 15 degrees and 45 degrees.

[0018] Preferably, in the compressor control method embodiment provided by the application, further comprising:

[0019] Obtaining the real-time speed and the target speed of the compressor, obtaining the speed loop output of the compressor with the target speed as the reference input of the speed loop of the compressor and the real-time speed as the feedback input of the speed loop of the compressor.

[0020] Preferably, in the embodiment of the compressor control method provided by the application, in the step S5, the direct current bus voltage of the compressor is predicted and reconstructed; comprising:

[0021] According to the formula The direct current bus voltage of the compressor is predicted and reconstructed to obtain the reconstructed direct current bus voltage of the compressor.

[0022] Wherein, x n is the direct current bus voltage measurement value corresponding to the current n moment, x n―2 is the direct current bus voltage measurement value corresponding to the n-2 moment, y n is the direct current bus voltage reconstruction value corresponding to the current n moment, y n―1 is the direct current bus voltage reconstruction value corresponding to the n-1 moment, y n―2 is the direct current bus voltage reconstruction value corresponding to the n-2 moment.

[0023] A, B, C and D are reconstruction coefficients, and B = 2ξKωf s , Wherein, K is a constant between 0 and 1, fs is the sampling frequency of the direct current bus voltage, ξ is the damping coefficient of the compressor, and ω is the three-phase voltage frequency of the compressor.

[0024] Preferably, in the embodiment of the compressor control method provided by the application, the first preset range of the preset speed is 95% to 105% of the preset speed.

[0025] Preferably, in the embodiment of the compressor control method provided by the application, the method further comprises:

[0026] The method further comprises:

[0027] In the process of the speed of the compressor exceeding the preset speed and continuing to rise or being a constant value greater than the preset speed, and when the step S4 is executed, if the speed of the compressor starts to drop and drops to the second preset range of the preset speed, the step S4 is exited, and the step S6 is executed.

[0028] The application also provides a compressor control system, which comprises a module for executing the method as described above.

[0029] The application also provides an outdoor unit, which comprises a compressor and a controller; the controller is used to execute the compressor control method as described above.

[0030] The compressor control method, the control system and the outdoor unit have the following beneficial effects: the compressor can ensure that the fluctuation of the three-phase current of the compressor is reduced and the operation efficiency of the compressor is improved when the compressor operates at a high frequency. BRIEF DESCRIPTION OF DRAWINGS

[0031] The application will be further described below in conjunction with the drawings and embodiments. In the drawings:

[0032] Figure 1 is a program flow chart of an embodiment of the compressor control method of the application;

[0033] Figure 2 is a control logic block diagram of an embodiment of the compressor control method of the application;

[0034] Figure 3 is a control logic block diagram of another embodiment of the compressor control method of the application. DETAILED DESCRIPTION

[0035] In order to have a clearer understanding of the technical features, objectives and effects of the application, the specific embodiments of the application will be described in detail below with reference to the drawings.

[0036] As shown in Figure 1 , an embodiment of the compressor control method of the application is shown. In Figure 1 the embodiment of the compressor control method of the application shown, the method comprises the following steps: S1, obtaining the three-phase current of the compressor and the direct-current bus voltage of the compressor, and converting the three-phase current of the compressor to obtain the q-axis current and the d-axis current. S2, constructing the first current loop and the second current loop corresponding to the compressor, wherein the q-axis current is the feedback input of the first current loop, and the speed loop output of the compressor is the reference input of the first current loop; the d-axis current is the feedback input of the second current loop corresponding to the compressor, and a preset value is the reference input of the second current loop. S3, obtaining the real-time speed of the compressor, and confirming whether the real-time speed of the compressor is within a first preset range of a preset speed, wherein the current of the compressor will fluctuate when the compressor is at the preset speed; if yes, step S4 is executed, otherwise step S6 is executed. S4, compensating the speed loop output of the compressor within a preset time length before and after the current zero point of the compressor, so as to take the compensated speed loop output as the reference input of the first current loop. S5, predicting and reconstructing the direct-current bus voltage of the compressor, and generating the control signal corresponding to the compressor by SVPWM modulation according to the reconstructed direct-current bus voltage of the compressor, the output of the first current loop and the output of the second current loop, and step S7 is executed. S6, generating the control signal corresponding to the compressor by SVPWM modulation according to the direct-current bus voltage of the compressor, the output of the first current loop and the output of the second current loop, and step S7 is executed. S7, controlling the driving circuit of the compressor by the control signal.

[0037] Based on step S1, the three-phase current signals of the compressor can be acquired by the sampling circuit, and the q-axis current and the d-axis current can be obtained by converting the three-phase current signals. The conversion process from the three-phase current signals to the q-axis current and the d-axis current can be implemented by using the current commonly used technical means, which is not limited here. The process of acquiring the three-phase current signals of the compressor can also be implemented by using the current commonly used technical means, which is not limited here. At the same time, the DC bus voltage of the compressor can also be acquired by the sampling circuit, and the voltage acquisition process can be implemented by using the current commonly used technical means, which is not limited here. As shown in Figure 2 , the AC input of the compressor 200 is sampled to obtain three-phase currents i a , i b , i c , and converted to obtain q-axis current i q and d-axis current i d .

[0038] Based on step S2, as shown in Figure 2 and Figure 3 , the first current loop 121 and the second current loop 122 are constructed, and the inner loop control of the compressor is realized through the first current loop 121 and the second current loop 122. The first current loop 121 is used to obtain the corresponding voltage adjustment amount according to the q-axis current of the compressor. Specifically, the obtained q-axis current is taken as the feedback input of the first current loop, and the speed loop 110 output of the compressor is taken as the reference input of the first current loop, so as to perform the control process of the first current loop. It can be understood that the speed loop output of the compressor is the q-axis current control amount. The second current loop is used to obtain the corresponding voltage adjustment amount according to the d-axis current of the compressor. The obtained d-axis current is taken as the feedback input of the second current loop, and a preset value is taken as the reference input of the second current loop, so as to perform the control process of the second current loop. In a specific embodiment, the first current loop 121 and the second current loop 122 are both realized by PI controllers. The parameter selection of the PI controller can be realized according to the current commonly used PI controller construction method. The speed loop 110 of the compressor is the outer loop of the compressor.

[0039] Based on step S3, during the operation of the compressor, the rotational speed of the compressor is acquired in real time to obtain a corresponding real-time rotational speed. The real-time rotational speed is judged to confirm whether the compressor has a risk of current jitter at the real-time rotational speed, that is, whether the current real-time rotational speed is at a critical point of generating current jitter. It can also be understood as confirming whether the current rotational speed is close to the preset rotational speed. Wherein, when the compressor operates at the preset rotational speed, current jitter will occur, and when the current rotational speed of the compressor is close to the preset rotational speed, the compressor has a risk of current jitter. Therefore, corresponding operations can be performed before current jitter occurs to reduce the possibility of current jitter of the compressor. Wherein, the preset rotational speed corresponding to each compressor can be obtained according to the specific circuit parameters of the compressor, and the preset rotational speed corresponding to each different compressor can be the same or different.

[0040] Based on step S4, when it is judged that the real-time rotational speed of the compressor is close to the preset rotational speed, the speed loop 110 output of the compressor, that is, the q-axis current control quantity, is compensated within a preset time length before and after the zero-crossing point of the current of the compressor. As shown in Figure 2 , in the operation process of the q-axis current control quantity and the q-axis current (corresponding to the feedback input of the first current loop), the compensation value is added to the q-axis current control quantity, and the compensated q-axis current control quantity and the q-axis current are operated and input to the first current loop to obtain the corresponding output.

[0041] Based on step S5, the direct-current bus voltage of the compressor is predicted and reconstructed to obtain a reconstructed direct-current bus voltage. Based on the reconstructed direct-current bus voltage and the outputs of the first current loop and the second current loop, SVPWM modulation is performed to obtain the control signal of the compressor. The specific process of SVPWM modulation can refer to the currently commonly used SVPWM modulation process. Based on Figure 2 , the direct-current bus voltage u dc can be reconstructed and calculated by the reconstruction calculation module 130. After reconstruction, the SVPWM modulation module 140 is used for modulation calculation and the corresponding output is obtained and input to the driving circuit 150 of the compressor 200.

[0042] Based on step S6, when it is judged based on step S3 that the compressor does not have a risk of current jitter at the current real-time rotational speed, SVPWM modulation is directly performed according to the current direct-current bus voltage and the outputs of the first current loop and the second current loop to obtain the control signal of the compressor. The specific process of SVPWM modulation can refer to the currently commonly used SVPWM modulation process. Specifically, as shown in Figure 3 , the first current loop 121 is directly controlled by the speed loop 110 and the q-axis current of the compressor, and the direct-current bus voltage u dcThe modulation calculation is performed by the SVPWM modulation module 140, and the corresponding output is input into the drive circuit 150 of the compressor 200.

[0043] Based on step S7, after the corresponding control signal is obtained based on the above process, the drive circuit of the compressor can be controlled according to the control signal, and then the specific working process of the compressor is controlled. The drive circuit of the compressor generally includes an inverter circuit composed of power switch tubes, and the control signal is used to control the turn-on and turn-off of each switch tube, so as to finally realize the control process of the input voltage or current of the compressor, and then realize the adjustment process of the speed of the compressor. It can be understood that the control signal generated in the SVPWM modulation process is a PWM signal, and the control process of the compressor can be understood as the process of generating a PWM signal that meets the requirements.

[0044] It can be understood that in the process described based on the above steps, after step S7 is executed, that is, during the adjustment of the speed of the compressor, after the speed of the compressor is adjusted, steps S1 and the actions after it can be repeatedly executed to ensure that the current fluctuation of the compressor does not occur during the continuous adjustment of the speed of the compressor.

[0045] In a specific embodiment, the reference speed (corresponding to the target speed) of the compressor is set to W1, the current speed of the compressor is obtained by measurement W2, and the speed of the compressor is adjusted from W2 to W1 by the above process. During the adjustment process, the speed of the compressor is adjusted to W3, and when the speed of the compressor is W3, there may be current fluctuation, and at this time, the control process of the compressor can be realized through steps S4, S5 and S7. Once the speed of the compressor passes through the risk speed, the control of the compressor can be performed according to the process of steps S6 and S7.

[0046] Optionally, the reference input of the second current loop can be set to zero. Considering that the q-axis current of the compressor acts on the active power of the compressor, for example, rotation, and the d-axis current of the compressor acts on the reactive power of the compressor, for example, heating, the purpose of constructing the second current loop is to adjust the operation of the compressor to minimize the useless work of the compressor, and therefore the reference input of the second current loop of the compressor can be set to zero to achieve the purpose of improving the efficiency of the compressor.

[0047] In an embodiment, in step S4, the speed loop output of the compressor is compensated within a preset time length before and after the zero crossing point of the current of the compressor, including: obtaining the product of the speed loop output of the compressor and a compensation coefficient to obtain the compensated speed loop output, wherein the compensation coefficient is a constant not equal to zero. That is, when the speed loop output of the compressor is compensated, the speed loop output of the compressor can be directly multiplied by the compensation coefficient to obtain the compensated speed loop output, and the speed loop output is used as the parameter input of the first current loop. In a specific embodiment, the compensation coefficient can be obtained by the formula obtaining a reference input i of the first current loop q_ref wherein is the speed loop output of the compressor, and k is a compensation coefficient. In another embodiment, the compensation process is modified, and the compensation value can be obtained based on the compensation value (as shown in Figure 2 ), so that the sum of the compensation value and the speed loop output of the compressor is used as the reference input of the first current loop.

[0048] In an embodiment, in step S4, the speed loop output of the compressor is compensated within a preset time period before and after the current zero-crossing point of the compressor, including: obtaining the current zero-crossing point of the compressor, obtaining a first time point before the current zero-crossing point as a starting point and a second time point after the current zero-crossing point as an ending point to obtain a preset time period, and compensating the speed loop output of the compressor within the preset time period. Specifically, during the operation of the compressor, the zero-crossing point state in the operation of the compressor is obtained based on an internal algorithm, and the current current zero-crossing point of the compressor can be calculated according to the current operating state of the compressor. During the rotation of the compressor, a time point before the current zero-crossing point is selected as a starting point, and a time point after the current zero-crossing point is selected as an ending point, and the time period from the starting point to the ending point is obtained as a preset time period. The speed loop of the compressor is compensated within this time period. And execute the following steps.

[0049] In an embodiment, the first time point is a time point before the current zero-crossing point with a current phase angle of -15 degrees to -45 degrees; and / or the second time point is a time point after the current zero-crossing point with a current phase angle of 15 degrees to 45 degrees. Specifically, the first time point or the second time point can be obtained according to the current phase angle during the rotation of the compressor. The time point when the current phase angle of the compressor is zero is the zero-crossing point, the first time point is selected between -15 degrees and -45 degrees before the zero degree, and the second time point is selected between 15 degrees and 45 degrees after the zero degree. In an embodiment, during the selection of the first time point and the second time point, the zero-crossing point is taken as the center, so that the first time point and the second time point are exactly opposite numbers, that is, the time difference from the zero-crossing point is the same, for example, the first time point is -15 degrees and the second time point is 15 degrees; the first time point is -30 degrees and the second time point is 30 degrees.

[0050] In an embodiment, the compressor control method of the present application further comprises: obtaining a real-time rotating speed of the compressor and a target rotating speed, using the target rotating speed as the reference input of the speed loop of the compressor and the real-time rotating speed as the feedback input of the speed loop of the compressor to obtain the speed loop output of the compressor. Specifically, according to Figure 2The speed loop of the compressor takes the set target rotating speed as a reference input and takes the real-time rotating speed of the compressor as a feedback input to obtain a reference input of the first current loop.

[0051] In an embodiment, in step S5, the DC bus voltage of the compressor is predicted and reconstructed, including: according to the formula The DC bus voltage of the compressor is predicted and reconstructed to obtain the reconstructed DC bus voltage of the compressor. Wherein, x n is the DC bus voltage measurement value corresponding to the current n moment, x n―2 is the DC bus voltage measurement value corresponding to n-2 moment, y n is the DC bus voltage reconstruction value corresponding to the current n moment, y n―1 is the DC bus voltage reconstruction value corresponding to n-1 moment, y n―2 is the DC bus voltage reconstruction value corresponding to n-2 moment. A, B, C and D are reconstruction coefficients, and B = 2ξKωf s , Wherein, K is a constant between 0 and 1, fs is the sampling frequency of the DC bus voltage, ξ is the damping coefficient of the compressor, and ω is the three-phase voltage frequency of the compressor.

[0052] Specifically, the current DC bus voltage measurement value can be reconstructed according to the above reconstruction formula to obtain the reconstruction value of the current bus DC voltage, that is, to obtain the reconstructed DC bus voltage for the following steps. In the measurement process of the DC bus voltage, the DC bus voltage can be sampled and calculated according to the set sampling frequency, and finally the measurement value of the DC bus voltage is obtained. And it can be taken as a unit time interval, for example, the interval between n moment and n-1 moment is one unit time interval, that is, one sampling time. Simply put, n-1 moment is the last sampling moment of n moment. Similarly, the interval between n moment and n-2 moment is two unit time intervals, that is, two sampling times, and n-2 moment is the last two sampling moments of n moment.

[0053] In an embodiment, in order to avoid the occurrence of jitter, the compressor speed adjustment process usually starts to enter step S4 in the range close to the preset rotating speed. The compressor speed adjustment process can be a process of adjusting from large to small, or a process of adjusting from small to large. Therefore, a certain range can be set according to the preset rotating speed, for example, when the current rotating speed fluctuates within 5% of the preset rotating speed, step S4 is entered for adjustment. The first preset range can be adjusted as needed.

[0054] In an embodiment, in the compressor control method provided by the application, further comprising: when the rotating speed of the compressor continues to rise or is a constant value greater than the preset rotating speed, and step S4 is executed, if the rotating speed of the compressor starts to drop and drops to a second preset range of the preset rotating speed, then step S4 is exited and step S6 is executed. In simple terms, when the rotating speed of the compressor is in a climbing state, when the rotating speed of the compressor reaches the first preset range of the preset rotating speed, step S4 is entered, so as to maintain the rotating speed of the compressor to continue to rise in the process of executing step S4. When executing step S4 and step S5, if a series of factors such as too high current load of the compressor or too high exhaust temperature or too high outer ring temperature occur, the system judges that the frequency of the compressor needs to be reduced, and the compressor will implement the frequency reduction operation according to the instruction. In order to ensure that the compressor does not distort in the process of executing step S4 and step S5, when the rotating speed of the compressor drops to the second preset range of the preset rotating speed, step S4 and step S5 are exited, and step S6 is directly executed. In an embodiment, the second preset range of the preset rotating speed is 95%-99% of the preset rotating speed. The second preset range can be selected according to needs, and is different from the first preset range to avoid repeatedly entering step S4 and step S5.

[0055] In addition, in the compressor control system provided by the application, the compressor control system comprises a module for executing the method described above. That is, the compressor control system has functions for implementing the corresponding steps executed in the above method. Each function can be implemented by hardware, or can be implemented by hardware executing corresponding software. The corresponding hardware or software comprises one or more modules corresponding to the above functions. That is, one or more modules are used to execute the steps in the above method respectively. The specific cooperation operation between each module can refer to the specific process of the above method, which will not be described here.

[0056] In addition, in the outdoor unit provided by the application, the outdoor unit comprises a compressor and a controller; the controller is used to execute the compressor control method of any one of the above. Specifically, according to the embodiments of the application, the process described above with reference to the flow chart can be implemented as a computer software program. The controller provided by the outdoor unit is used to implement.

[0057] The above control method can effectively suppress the beat frequency component of the direct current bus output voltage of the drive board device of the compressor, reduce the current fluctuation of the three-phase output to the compressor under high-frequency operation of the compressor, and ensure the high efficiency of the whole machine operation.

[0058] It can be understood that the above embodiments only express the preferred embodiments of the present application, the description is more specific and detailed, but it cannot be understood as the limitation of the patent scope of the present application; it should be pointed out that for ordinary skilled in the art, the above technical features can be freely combined without departing from the concept of the present application, and several modifications and improvements can be made, which belong to the protection scope of the present application; therefore, any equivalent transformation and modification made with the patent claim scope of the present application shall belong to the coverage of the patent claim of the present application.

Claims

1. A compressor control method characterized by, The method comprises the following steps: S1, acquiring three-phase currents of the compressor and a DC bus voltage of the compressor, and converting the three-phase currents of the compressor to obtain a q-axis current and a d-axis current; S2, constructing a first current loop and a second current loop corresponding to the compressor, wherein the q-axis current is taken as a feedback input of the first current loop, a speed loop output of the compressor is taken as a reference input of the first current loop, the d-axis current is taken as a feedback input of the second current loop corresponding to the compressor, and a preset value is taken as a reference input of the second current loop; S3, acquiring a real-time rotating speed of the compressor, and determining whether the real-time rotating speed of the compressor is within a first preset range of a preset rotating speed, wherein the compressor will have current jitter at the preset rotating speed; if yes, executing step S4, otherwise executing step S6; S4, compensating the speed loop output of the compressor within a preset time length before and after a current zero-crossing point of the compressor, and taking the compensated speed loop output as the reference input of the first current loop; S5, predicting and reconstructing the DC bus voltage of the compressor, and generating a control signal corresponding to the compressor through SVPWM modulation according to the reconstructed DC bus voltage of the compressor, an output of the first current loop and an output of the second current loop, and executing step S7; S6, generating a control signal corresponding to the compressor through SVPWM modulation according to the DC bus voltage of the compressor, the output of the first current loop and the output of the second current loop, and executing step S7; S7, controlling a driving circuit of the compressor through the control signal; In the step S5, the predicting and reconstructing the DC bus voltage of the compressor comprises: According to the formula predicting a reconstruction of the compressor DC bus voltage to obtain a reconstructed compressor DC bus voltage; wherein, is a direct current bus voltage measurement value corresponding to a current n time, is a direct current bus voltage measurement value corresponding to n-2 time, is a direct current bus voltage reconstruction value corresponding to a current n time, is a direct current bus voltage reconstruction value corresponding to n-1 time, is a direct current bus voltage reconstruction value corresponding to n-2 time; A, B, C and D are reconstruction coefficients, and , , , wherein, is a constant between 0-1, is the sampling frequency of the DC bus voltage, is the damping coefficient of the compressor, is the three-phase voltage frequency of the compressor.

2. The compressor control method of claim 1, wherein The preset value is zero; and / or the first preset range of the preset rotating speed is 95% to 105% of the preset rotating speed.

3. The compressor control method of claim 1, wherein, In the step S4, the compensating the speed loop output of the compressor within the preset time length before and after the current zero-crossing point of the compressor comprises: Obtaining a product of the speed loop output of the compressor and a compensation coefficient to obtain the compensated speed loop output, wherein the compensation coefficient is a constant not equal to zero.

4. The compressor control method of claim 1, wherein In the step S4, the compensating the speed loop output of the compressor within the preset time length before and after the current zero-crossing point of the compressor comprises: Obtaining a current zero-crossing point of the compressor, obtaining a preset time length from a first time point before the current zero-crossing point to a second time point after the current zero-crossing point, and compensating the speed loop output of the compressor within the preset time length.

5. The compressor control method according to claim 4, characterized by, The first time point is a time point before the current zero-crossing point at which a current phase angle is between -15 degrees and -45 degrees; and / or the second time point is a time point after the current zero-crossing point at which the current phase angle is between 15 degrees and 45 degrees.

6. The compressor control method of claim 1, wherein The method further comprises: obtaining a real-time rotating speed of the compressor and a target rotating speed, taking the target rotating speed as a reference input of a speed loop of the compressor and taking the real-time rotating speed as a feedback input of the speed loop of the compressor to obtain a speed loop output of the compressor.

7. The compressor control method of claim 1, wherein The method further comprises: In the process that the rotating speed of the compressor continues to rise beyond the preset rotating speed or is a constant value greater than the preset rotating speed, and the step S4 is executed, if the rotating speed of the compressor starts to drop and drops to a second preset range of the preset rotating speed, the step S4 is exited and the step S6 is executed.

8. A compressor control system characterized by, The compressor control system comprises a module for executing the method according to any one of claims 1 to 7.

9. An outdoor unit characterized by comprising: The compressor control system comprises a module for executing the method according to any one of claims 1 to 7. The compressor control system comprises a module for executing the method according to any one of claims 1 to 7. The compressor control system comprises a module for executing the method according to any one of claims 1 to 7.

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