Compressor control method and system and outdoor unit

Abstract

The invention relates to a compressor control method and system and an outdoor unit. Comprising the steps that S1, three-phase current and direct-current bus voltage of a compressor are obtained, and the three-phase current is converted to obtain q-axis current and d-axis current; s2, constructing a first current loop and a second current loop corresponding to the compressor; s3, whether the real-time rotating speed of the compressor is within the first preset range of the preset rotating speed or not is determined; if so, executing S4, otherwise, executing S6; s4, speed ring output of the compressor is compensated within the preset duration before and after the current zero crossing 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, a control signal corresponding to the compressor is generated according to the direct-current bus voltage of the compressor, and S7 is executed; and S7, a drive circuit of the compressor is controlled through the control signal. The three-phase current fluctuation of compressor operation can be reduced, and the operation efficiency of the compressor is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of compressor control, and more particularly to a compressor control method, a control system and an outdoor unit. Background Art

[0002] Currently, in the technologies related to HVAC equipment, electrolytic capacitor-free solutions are gradually being adopted to replace the compressor drive parts of HVAC equipment. Electrolytic capacitors are small in size and low in cost, which meets the technical development needs of HVAC equipment. However, due to their low capacity for storing electrical energy, the output DC bus voltage fluctuates greatly during the operation of the HVAC unit, which causes the control of the three-phase current output to the compressor to be unstable when the compressor is running at high frequency. The waveform quality is poor and the control is difficult. Therefore, after the outdoor drive control board device is changed to an electrolytic capacitor-free device, when the DC bus voltage fluctuates too much, the output beat frequency of the three-phase current output by the drive control board device is large when the compressor is running at high frequency, and the resulting waveform jitter problem becomes a technical problem that needs to be solved during the operation of the compressor. Summary of the Invention

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

[0004] The technical solution adopted by the present invention to solve the technical problem is to construct a compressor control method, comprising the following steps:

[0005] S1. Obtaining 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 a q-axis current and a 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 used as a feedback input of the first current loop and the speed loop output of the compressor is used as a reference input of the first current loop, and the d-axis current is used as a feedback input of the second current loop corresponding to the compressor and a preset value is used as a reference input of the second current loop;

[0007] S3. Obtain the real-time speed of the compressor and confirm whether the real-time speed of the compressor is within a first preset range of preset speeds, wherein the compressor will generate current jitter at the preset speed; if so, execute step S4; otherwise, execute step S6;

[0008] S4. Compensating the speed loop output of the compressor within a preset time period before and after the current of the compressor crosses zero, so as to use the compensated speed loop output as a reference input of the first current loop;

[0009] S5. Predict and reconstruct the DC bus voltage of the compressor, perform SVPWM modulation based on the reconstructed DC bus voltage of the compressor, the output of the first current loop, and the output of the second current loop to generate a control signal corresponding to the compressor, and execute step S7;

[0010] S6, performing 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 to generate a control signal corresponding to the compressor, and executing step S7;

[0011] S7. Control the driving circuit of the compressor using the control signal.

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

[0013] Preferably, in an embodiment of the compressor control method provided by the present invention, in step S4, compensating the speed loop output of the compressor within a preset time period before and after the current of the compressor crosses zero, includes:

[0014] The product of the speed loop output of the compressor and a compensation coefficient is obtained to obtain a compensated speed loop output, wherein the compensation coefficient is a non-zero constant.

[0015] Preferably, in an embodiment of the compressor control method provided by the present invention, in step S4, compensating the speed loop output of the compressor within a preset time period before and after the current of the compressor crosses zero, includes:

[0016] The moment when the current of the compressor crosses zero is obtained, and a preset time length is obtained with a first moment before the current crosses zero as a starting point and a second moment after the current crosses zero as an end point, so as to compensate the speed loop output of the compressor within the preset time length.

[0017] Preferably, in the compressor control method embodiment provided by the present invention, the first moment is the moment when the current phase angle is between -15 degrees and -45 degrees before the current zero-crossing moment; and / or the second moment is the moment when the current phase angle is between 15 degrees and 45 degrees after the current zero-crossing moment.

[0018] Preferably, in the embodiment of the compressor control method provided by the present invention, the method further includes:

[0019] The real-time speed and target speed of the compressor are obtained, and the speed loop output of the compressor is obtained by taking 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 an embodiment of the compressor control method provided by the present invention, in step S5, predicting and reconstructing the DC bus voltage of the compressor includes:

[0021] According to the formula Predicting and reconstructing the DC bus voltage of the compressor to obtain a reconstructed DC bus voltage of the compressor;

[0022] Among them, x n is the DC bus voltage measurement value corresponding to the current moment n, x n―2 is the DC bus voltage measurement value corresponding to time n-2, y n is the reconstructed value of the DC bus voltage corresponding to the current moment n, y n―1 is the reconstructed value of the DC bus voltage corresponding to time n-1, y n―2 is the reconstructed value of the DC bus voltage corresponding to time n-2;

[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 DC bus voltage, ξ is the damping coefficient of the compressor, and ω is the three-phase voltage frequency of the compressor.

[0024] Preferably, in an embodiment of the compressor control method provided by the present invention, 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 present invention, the method further includes:

[0026] The method further comprises:

[0027] When the speed of the compressor exceeds the preset speed and continues to rise or is a constant value greater than the preset speed, and when step S4 is executed, if the speed of the compressor starts to decrease and drops to a second preset range of the preset speed, step S4 is exited and step S6 is executed.

[0028] The present invention also discloses a compressor control system, which includes: a module for executing the method described above.

[0029] The present invention also provides an outdoor unit, comprising a compressor and a controller; the controller is used to execute the compressor control method described above.

[0030] The compressor control method, control system and outdoor unit implemented in the present invention have the following beneficial effects: they can ensure that when the compressor is running at high frequency, the fluctuation of the three-phase current of the compressor is reduced, and the operating efficiency of the compressor is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0032] Figure 1 This is a flowchart of an embodiment of a compressor control method of the present invention;

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

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

[0035] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0036] like Figure 1 FIG. 1 shows an embodiment of a compressor control method of the present invention. Figure 1 In an embodiment of a compressor control method of the present invention, the method includes the following steps: S1. Obtaining 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 the q-axis current and the d-axis current. S2. Constructing a first current loop and a second current loop corresponding to the compressor, wherein the q-axis current is used as the feedback input of the first current loop and the speed loop output of the compressor is used as the reference input of the first current loop, and the d-axis current is used as the feedback input of the second current loop corresponding to the compressor and a preset value is used as 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 the preset speed, wherein the compressor will experience current jitter at the preset speed; if so, executing step S4; otherwise, executing step S6. S4. Compensating the speed loop output of the compressor within a preset time period before and after the current zero point of the compressor, so that the compensated speed loop output is used as the reference input of the first current loop. S5. Predict and reconstruct the DC bus voltage of the compressor, and perform SVPWM modulation based on the reconstructed DC bus voltage of the compressor, the output of the first current loop, and the output of the second current loop to generate a control signal corresponding to the compressor, and then proceed to step S7. S6. Perform SVPWM modulation based on the DC bus voltage of the compressor, the output of the first current loop, and the output of the second current loop to generate a control signal corresponding to the compressor, and then proceed to step S7. S7. Control the drive circuit of the compressor using the control signal.

[0037] Based on step S1, the three-phase current signal of the compressor can be collected through the sampling circuit, and the three-phase current signal can be converted to obtain the q-axis current and the d-axis current. The conversion process based on the three-phase current signal to the q-axis current and the d-axis current can adopt the currently commonly used technical means, which is not limited here. The process of acquiring the three-phase current signal of the compressor can also adopt the currently commonly used technical means, which is not limited here. At the same time, the DC bus voltage of the compressor can also be obtained through the sampling circuit. The voltage acquisition process can adopt the currently commonly used technical means, which is not limited here. Figure 2 As shown, the AC input of the compressor 200 is sampled to obtain the three-phase current i a 、i b 、i c , and convert it to get the q-axis current i q and d-axis current i d .

[0038] Based on step S2, Figure 2 and Figure 3 As shown, a first current loop 121 and a second current loop 122 are constructed, and the inner loop control of the compressor is implemented through the first current loop 121 and the second current loop 122. The first current loop 121 is used to obtain a corresponding voltage adjustment value based on the compressor's q-axis current. Specifically, the obtained q-axis current is used as the feedback input of the first current loop, and the output of the compressor's speed loop 110 is used as the reference input of the first current loop to implement the control process of the first current loop. It can be understood that the output of the compressor's speed loop is the q-axis current control value. The second current loop is used to obtain a corresponding voltage adjustment value based on the compressor's d-axis current. The obtained d-axis current is used as the feedback input of the second current loop, and a preset value is used as the reference input of the second current loop to implement the control process of the second current loop. In one specific embodiment, both the first current loop 121 and the second current loop 122 are implemented using PI controllers. The parameters of the PI controller can be selected according to currently commonly used PI controller construction methods. The compressor's speed loop 110 is the outer loop of the compressor.

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

[0040] Based on step S4, when it is determined that the real-time speed of the compressor is close to the preset speed, the output of the speed loop 110 of the compressor, i.e., the q-axis current control amount, is compensated within the preset time period before and after the current zero point of the compressor. Figure 2 As shown, in the calculation 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 The q-axis current control variable is compensated, and the compensated q-axis current control variable and the q-axis current are calculated and input into the first current loop to obtain a corresponding output.

[0041] Based on step S5, the DC bus voltage of the compressor is predicted and reconstructed to obtain the reconstructed DC bus voltage. Based on the reconstructed DC 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. Figure 2 , the DC bus voltage u can be calculated by reconstructing the calculation module 130 dc After reconstruction, the SVPWM modulation module 140 performs modulation calculation and obtains a corresponding output which is input into the drive circuit 150 of the compressor 200 .

[0042] Based on step S6, in the judgment process based on step S3, when the compressor does not have the risk of current jitter at the current real-time speed, SVPWM modulation can be directly performed based on the current DC 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, Figure 3 As shown, the first current loop 121 is controlled directly through the speed loop 110 and the q-axis current of the compressor, and the DC bus voltage u is directly dcThe SVPWM modulation module 140 performs modulation calculation and obtains a corresponding output which is input into the driving circuit 150 of the compressor 200 .

[0043] Based on step S7, after obtaining the corresponding control signal based on the above process, the compressor's drive circuit can be controlled based on the control signal, thereby controlling the specific operation of the compressor. The compressor's drive circuit generally includes an inverter circuit composed of power switching transistors. The control signal is used to control the on and off of each switching transistor, ultimately achieving the control process of the compressor input voltage or current, and then achieving the process of adjusting the compressor speed. It can be understood that the control signal generated during 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 executing step S7, that is, in the process of adjusting the speed of the compressor, after the speed of the compressor is adjusted, step S1 and the subsequent actions can be repeated to ensure that the compressor current jitter does not occur during the continuous adjustment of the compressor speed.

[0045] To illustrate with a specific embodiment, the reference speed of the compressor (corresponding to the target speed) is set to W1, and the current speed of the compressor is measured to be W2. The speed of the compressor is controlled to adjust from W2 to W1 through the above process. During the adjustment process, the speed of the compressor is adjusted to W3. When the speed of the compressor is W3, there may be current jitter. At this time, the control process of the compressor can be implemented through steps S4, S5 and S7. Once the speed of the compressor bypasses the risk speed, the compressor can be controlled 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 compressor's q-axis current contributes to the compressor's active power, such as rotation, and the compressor's d-axis current contributes to the compressor's idle power, such as heat generation, the purpose of constructing the second current loop is to adjust the compressor's operation to minimize idle work. Therefore, the reference input of the compressor's second current loop can be set to zero to improve compressor efficiency.

[0047] In one embodiment, in step S4, the speed loop output of the compressor is compensated within a preset time period before and after the current of the compressor crosses zero, including: 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 that is not zero. That is, when compensating the speed loop output of the compressor, 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, it can be calculated by the formula Get the reference input i of the first current loop q_ref ,in is the speed loop output of the compressor, and k is the compensation coefficient. In another embodiment, the compensation process can be modified according to Get compensation value (like Figure 2 As shown), 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 one 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 moment of the compressor, obtaining a preset time period with the first moment before the current zero-crossing moment as the starting point and the second moment after the current zero-crossing moment as the end point, so as to compensate the speed loop output of the compressor within the preset time period. Specifically, during the operation of the compressor, the zero-crossing state of the compressor during operation is obtained based on an internal algorithm. The current zero-crossing moment of the compressor current can be calculated based on the current operating state of the compressor. During the rotation of the compressor, a moment before the current zero-crossing moment is selected as the starting point, and a moment after the current zero-crossing moment is selected as the middle end point. The time period from the starting point to the end point is obtained as the preset time period. The speed loop of the compressor is compensated within this time period. The subsequent steps are then executed.

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

[0050] In one embodiment, the compressor control method of the present invention further includes: obtaining the real-time speed and target speed of the compressor, and obtaining the speed loop output of the compressor by using 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. Figure 2During the operation of the compressor's speed loop, the set target speed is used as the reference input, and the real-time compressor speed is used as the feedback input. This speed loop is used to derive the reference input for the first current loop. The compressor's speed loop is the outer loop, used to generate the current adjustment target value, which the first current loop adjusts based on.

[0051] In one embodiment, in step S5, the DC bus voltage of the compressor is predicted and reconstructed; comprising: 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. n is the DC bus voltage measurement value corresponding to the current moment n, x n―2 is the DC bus voltage measurement value corresponding to time n-2, y n is the reconstructed value of the DC bus voltage corresponding to the current moment n, y n―1 is the reconstructed value of the DC bus voltage corresponding to time n-1, y n―2 is the reconstructed value of the DC bus voltage corresponding to time n-2. A, B, C and D are the 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 reconstructed value of the current bus DC voltage, that is, the reconstructed DC bus voltage is obtained to perform the subsequent steps. During the measurement of the DC bus voltage, the DC bus voltage can be sampled and calculated according to the set sampling frequency, and the measured value of the DC bus voltage can be finally obtained. And the sampling time interval can be used as the unit time interval, for example, the time n and the time n-1 are separated by a unit time interval, that is, by one sampling time. Simply understand, the time n-1 is the previous sampling time of the time n. Similarly, the time n and the time n-2 are separated by two unit time intervals, that is, by two sampling times, and the time n-2 are the previous two sampling times of the time n.

[0053] In one embodiment, to avoid jitter, the system typically begins to enter step S4 within a range close to a preset speed. The compressor speed adjustment process can be from high to low or from low to high. Therefore, a certain range can be set based on the preset speed. For example, if the current speed fluctuates within a range of 5% above or below the preset speed, the system proceeds to step S4 for adjustment. This first preset range can be adjusted as needed.

[0054] In one embodiment, the compressor control method provided by the present invention further includes: when the compressor speed continues to rise above a preset speed or remains constant above the preset speed, and during step S4, if the compressor speed begins to fall and falls within a second preset range of the preset speed, then step S4 is exited and step S6 is executed. Simply put, when the compressor speed is in a rising state, step S4 is entered when the compressor speed reaches the first preset range of the preset speed, so that the compressor speed continues to rise during step S4. During steps S4 and S5, if factors such as excessive compressor current load, excessive exhaust temperature, or excessive external ring temperature occur, the system determines that the compressor frequency needs to be reduced, and the compressor will implement frequency reduction according to the command. To ensure that the compressor does not experience distortion during steps S4 and S5, steps S4 and S5 are exited when the compressor speed falls within the second preset range of the preset speed, and step S6 is directly executed. In one embodiment, the second preset range of the preset speed is 95%-99% of the preset speed. The second preset range of values ​​can be selected as needed to form a difference with the first preset range to avoid repeatedly entering step S4 and step S5.

[0055] In another embodiment of a compressor control system provided by the present invention, the compressor control system includes a module for executing the above-described method. Specifically, the compressor control system has the functionality to implement the corresponding steps executed in the above-described method. Each of these functions can be implemented via hardware, or by hardware executing corresponding software implementations. The corresponding hardware or software includes one or more modules corresponding to the aforementioned functions. Specifically, the steps of the above-described method are respectively executed by one or more modules. The specific coordination between the modules can be referenced with the specific procedures of the above-described method and will not be further described here.

[0056] The present invention also provides an outdoor unit comprising a compressor and a controller configured to execute any of the above compressor control methods. Specifically, according to an embodiment of the present invention, the process described above with reference to the flowchart can be implemented as a computer software program and can be implemented by the controller provided in the outdoor unit.

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

[0058] It is understandable that the above embodiments only express the preferred implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the patent scope of the present invention. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention, the above technical features can be freely combined, and several deformations and improvements can be made, all of which fall within the scope of protection of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should fall within the scope of coverage of the claims of the present invention.

Claims

1. A compressor control method, characterized in that: The following steps are involved: S1. Acquire the three-phase current of the compressor and the DC bus voltage of the compressor, and convert the three-phase current of the compressor to obtain a q-axis current and a d-axis current; S2. Construct a first current loop and a second current loop corresponding to the compressor, wherein the q-axis current is used as a feedback input of the first current loop and the speed loop output of the compressor is used as a reference input of the first current loop, and the d-axis current is used as a feedback input of the second current loop corresponding to the compressor and a preset value is used as a 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 preset speeds, wherein the compressor will have current jitter at the preset speed; if so, executing step S4, otherwise executing step S6; S4, compensating the speed loop output of the compressor within a preset time period before and after the current of the compressor crosses zero, so as to use the compensated speed loop output as a reference input of the first current loop; S5, predicting and reconstructing the DC bus voltage of the compressor, and performing 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 to generate a control signal corresponding to the compressor, and executing step S7; S6, performing 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 to generate a control signal corresponding to the compressor, and executing step S7; S7. Control the driving circuit of the compressor through the control signal.

2. The compressor control method according to claim 1, characterized in that: The preset value is zero; and / or the first preset range of the preset rotation speed is 95% to 105% of the preset rotation speed.

3. The compressor control method according to claim 1, characterized in that: In the step S4, compensating the speed loop output of the compressor within a preset time period before and after the current of the compressor passes through zero, includes: The product of the speed loop output of the compressor and a compensation coefficient is obtained to obtain a compensated speed loop output, wherein the compensation coefficient is a non-zero constant.

4. The compressor control method according to claim 1, characterized in that: In the step S4, compensating the speed loop output of the compressor within a preset time period before and after the current of the compressor passes through zero, includes: The moment when the current of the compressor crosses zero is obtained, and a preset time length is obtained with a first moment before the moment when the current crosses zero as a starting point and a second moment after the moment when the current crosses zero as an end point, so as to compensate the speed loop output of the compressor within the preset time length.

5. The compressor control method according to claim 4, characterized in that: The first moment is the moment before the current zero-crossing moment when the current phase angle is between -15 degrees and -45 degrees; and / or the second moment is the moment after the current zero-crossing moment when the current phase angle is between 15 degrees and 45 degrees.

6. The compressor control method according to claim 1, characterized in that: The method further comprises: The real-time speed and the target speed of the compressor are obtained, and the speed loop output of the compressor is obtained by taking 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.

7. The compressor control method according to claim 1, characterized in that: In the step S5, the DC bus voltage of the compressor is predicted and reconstructed; include: According to the formula Predicting and reconstructing the DC bus voltage of the compressor to obtain a reconstructed DC bus voltage of the compressor; Among them, x n is the DC bus voltage measurement value corresponding to the current time n, x n―2 is the DC bus voltage measurement value corresponding to time n-2, y n is the DC bus voltage reconstruction value corresponding to the current time n, y n―1 is the DC bus voltage reconstruction value corresponding to time n-1, y n―2 is the reconstructed value of the DC bus voltage corresponding to time n-2; 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.

8. The compressor control method according to claim 1, characterized in that: The method further comprises: When the speed of the compressor exceeds the preset speed and continues to rise or is a constant value greater than the preset speed, and when executing step S4, if the speed of the compressor starts to decrease and drops to a second preset range of the preset speed, exit step S4 and execute step S6.

9. A compressor control system, characterized in that: The compressor control system comprises: a module for executing the method according to any one of claims 1 to 8.

10. An outdoor unit, characterized in that: Including compressor, and controller; The controller is used to execute the compressor control method according to any one of claims 1 to 8.

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