CN116357603A - Fan startup control method, device and air conditioning unit - Google Patents

Abstract

The invention discloses a fan starting control method and device and an air conditioning unit, wherein the method comprises the following steps: detecting the rotating speed of the fan when the fan rotates against the wind; determining a braking mode of the motor according to the rotating speed of the fan, and braking according to the braking mode; and determining whether braking is finished, and controlling the fan to start forward after braking is finished. The invention solves the problem of difficult upwind starting of the fan in the prior art, and realizes safe and reliable starting of the fan under upwind conditions.

Description

Fan startup control method, device and air conditioning unit

technical field

The present invention relates to the technical field of air conditioners, in particular to a method and device for fan startup control and an air conditioner unit.

Background technique

The headwind start of the fan has always been a problem in the industry. When the wind is strong in the environment, the fan of the outdoor unit in the off state of the air conditioner will be blown to reverse rotation. When the user needs to start the operation, if the reverse speed of the fan is high, the Cause the fan to fail to start, or even burn the frequency converter and motor.

At present, in the field of air conditioning, there are mainly two types of detection of the rotor position in the drive control of the outdoor fan, with a position sensor and without a position sensor. The method with a position sensor has high cost, short life and has requirements for the use environment, so it is generally used without Position sensing algorithm, but without position sensing algorithm, it is difficult to determine the rotor position and speed information before the motor starts and at the low speed stage. Inaccurate information leads to problems such as incomplete and unreliable reverse braking of the fan, which makes it difficult to start successfully.

No effective solution has been proposed so far for the problem of difficulty in starting the wind turbine against the wind in the related technology.

Contents of the invention

The invention provides a fan start control method, device and air-conditioning unit to at least solve the problem of difficulty in starting the fan against the wind in the prior art.

In order to solve the above technical problems, according to an aspect of the embodiments of the present invention, a fan startup control method is provided, including:

Detect the fan speed when the fan rotates against the wind;

Determine the braking mode of the motor according to the fan speed, and perform braking according to the braking mode;

Determine whether the brake is completed, and control the fan to start forward after the brake is completed.

Further, the braking mode of the motor is determined according to the speed of the fan, including:

Determine the speed level corresponding to the fan speed; wherein, the speed level includes at least: high speed, medium speed and low speed;

Determine the braking method according to the speed level.

Further, when the speed level is high speed, the braking method is determined according to the speed level, including:

Control the U-phase and V-phase of the stator winding of the motor to commutate;

After the U-phase and V-phase are commutated, the position and speed information of the rotor is obtained, and the motor is controlled to enter closed-loop braking according to the position and speed information of the rotor.

Further, when the speed level is medium speed, the braking method is determined according to the speed level, including:

All the three-phase upper bridge arms of the inverter are controlled to be turned off, and the duty cycle of the three-phase lower bridge arms is reduced.

Further, when the speed level is low, the braking method is determined according to the speed level, including:

All three-phase upper bridge arms of the inverter are controlled to be turned off, and all three-phase lower bridge arms are controlled to be turned on.

Further, determine whether braking is completed, including:

After the preset time, re-detect the fan speed to determine whether the fan speed is less than the preset threshold;

When the speed of the fan is less than a preset threshold, it is determined that braking is completed;

Otherwise, it is determined that braking is not done.

Further, it also includes:

When it is determined that the braking has not been completed, the braking mode of the motor is determined according to the re-detected fan speed, and the braking is performed according to the braking mode until the braking is completed.

Further, before detecting the fan speed when the fan rotates against the wind, it also includes:

Estimate the headwind speed through the state observer to determine whether the motor is reversed;

When the motor is reversed, trigger and detect the fan speed when the fan rotates against the wind;

Otherwise, the fan is controlled to start in the forward direction.

According to another aspect of the embodiments of the present invention, a fan startup control device is provided, including:

The detection module is used to detect the fan speed when the fan rotates against the wind;

The determination module is used to determine the braking mode of the motor according to the speed of the fan, and perform braking according to the braking mode;

The starting module is used to determine whether the braking is completed, and controls the fan to start forward after the braking is completed.

According to yet another aspect of the embodiments of the present invention, an air-conditioning unit is provided, and the external unit of the air-conditioning unit adopts the above-mentioned fan start-up control device.

According to yet another aspect of the embodiments of the present invention, there is provided a storage medium containing computer-executable instructions, and the computer-executable instructions are used to execute the above-mentioned fan start-up control method when executed by a computer processor.

In the present invention, a reliable fan startup scheme is provided. When the wind blows against the wind, the fan speed is detected to determine the corresponding motor braking mode for braking, and the fan is controlled to start in the forward direction after the brake is completed. In the above scheme, the corresponding optimal braking scheme is adopted for different fan speeds, and the difficulty in starting the fan at different headwind speeds is specifically solved. For example, it is difficult to determine the rotor position and speed information at the low speed stage, which leads to incomplete reverse braking of the fan. , Unreliable and difficult to start successfully, and the large current during the reverse braking process in the high-speed stage will damage the inverter and motor, etc., to achieve reliable and successful start while protecting the inverter and motor under headwind conditions.

Description of drawings

FIG. 1 is an optional flow chart of a fan start-up control method according to an embodiment of the present invention;

Fig. 2 is an optional circuit diagram of motor braking according to an embodiment of the present invention;

FIG. 3 is another optional flow chart of a fan startup control method according to an embodiment of the present invention;

Fig. 4 is an optional structural block diagram of a fan startup control device according to an embodiment of the present invention.

Detailed ways

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numerals in different drawings refer to the same or similar elements unless otherwise indicated. The implementations described in the following exemplary examples do not represent all implementations consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with aspects of the invention as recited in the appended claims.

Example 1

In the preferred embodiment 1 of the present invention, a fan start control method is provided, which can be directly applied to various fans that may rotate against the wind, such as common air conditioner outdoor fans or other outdoor fans. Specifically, FIG. 1 shows an optional flow chart of the method. As shown in FIG. 1, the method includes the following steps S102-S106:

S102: Detect the fan speed when the fan rotates against the wind;

S104: Determine the braking mode of the motor according to the speed of the fan, and perform braking according to the braking mode;

S106: Determine whether the braking is completed, and control the fan to start forward after the braking is completed.

In the above-mentioned embodiment, a reliable starting scheme of the fan is provided. When the wind blows against the wind, the rotation speed of the fan is detected to determine the corresponding braking mode of the motor for braking, and the fan is controlled to start in the forward direction after the braking is completed. In the above scheme, the corresponding optimal braking scheme is adopted for different fan speeds, and the difficulty in starting the fan at different headwind speeds is specifically solved. For example, it is difficult to determine the rotor position and speed information at the low speed stage, which leads to incomplete reverse braking of the fan. , Unreliable and difficult to start successfully, and the large current during the reverse braking process in the high-speed stage will damage the inverter and motor, etc., to achieve reliable and successful start while protecting the inverter and motor under headwind conditions.

In a preferred embodiment of the present invention, the rotating speed grades are divided into high speed, medium speed and low speed; It is difficult to start successfully. In the high-speed stage, there are problems such as large current damage to the inverter and motor during the reverse braking process. Therefore, it is necessary to carry out corresponding braking measures for different speed levels.

Specifically, when the speed level is high speed, the braking method is determined according to the speed level, including: controlling the U-phase and V-phase of the stator winding of the motor to commutate; after the U-phase and V-phase commutation, obtain the rotor position and According to the position and speed information of the rotor, the motor is controlled to enter closed-loop braking. For high-speed and above speed, in the software program control logic, the U-phase and V-phase in the stator winding of the motor are commutated and controlled to control the reverse rotation of the motor. Since the estimated rotor speed and position are known, the motor can directly enter the closed-loop headwind brake. Closed-loop braking can allow the motor to brake smoothly and reliably to reduce the speed at high speeds, effectively preventing large currents from damaging the drive board and motor during high-speed braking. Under the condition of closed-loop control, make it reach a lower speed, such as medium speed or low speed, and then enter the corresponding braking mode, so as to gradually reduce the speed and brake steadily.

Preferably, when the speed level is medium, determining the braking method according to the speed level includes: controlling all three-phase upper bridge arms of the inverter to be turned off, and reducing the duty cycle of the three-phase lower bridge arms. When the speed is below high speed and above medium speed, since the state observer is inaccurate in observing the speed in this speed range and below, if closed-loop braking is used again, the control will be out of control, which will cause the unit to stop due to failure. Therefore, in this speed range, the three-phase upper bridge arms of the sampling inverter are all turned off, and the three-phase lower bridge arms are braked by reducing the duty cycle. Optionally, the three-phase lower bridge arms are braked at a duty cycle of 30%. action.

Fig. 2 shows a motor braking circuit diagram, as shown in Fig. 2, which shows the inverter and the motor, and the part marked with the dotted line in the inverter is the three-phase lower bridge arm. When the three-phase lower bridge arm is turned on, the three-phase windings of the motor are short-circuited, the motor is converted into a generator state, the kinetic energy is converted into electrical energy, and the current generates a reverse torque in the magnetic field, thereby achieving the effect of buffer braking. If the speed range is controlled according to 100% duty cycle, the kinetic energy is too large and the conversion is too fast, there will be a surge in current, which will damage the inverter and motor, so reduce the duty cycle of the three-phase lower bridge arm at the medium speed stage, and slowly brake.

When the speed level is low, the braking method is determined according to the speed level, including: controlling all three-phase upper bridge arms of the inverter to be turned off, and controlling all three-phase lower bridge arms to be turned on. In the low-speed stage, all the three-phase upper bridge arms of the inverter are turned off, and the three-phase lower bridge arms are all turned on (according to 100% duty cycle control), realizing full short-circuit braking, and the electric energy generated by braking is transmitted between the inverter and Within the bearing range of the motor, fast and reliable braking effect can be achieved.

In the above process, when the brake is reached to the motor speed is 0 or less than a lower threshold, the reliable forward start starts. Specifically, determining whether to complete the braking includes: re-detecting the fan speed after a preset time, and judging whether the fan speed is less than a preset threshold; when the fan speed is lower than the preset threshold, determining that the braking is completed; otherwise, determining that the braking is not completed brake.

For each speed stage, one adjustment may not be able to complete the braking effect. Therefore, when it is determined that the braking has not been completed, determine the braking mode of the motor according to the re-detected fan speed, and perform braking according to the braking mode until the braking is completed. brake. For example, after braking at a high speed stage, the speed of the fan may be reduced to a medium speed. At this time, the brake is continued at a medium speed, and the speed is reduced to a low speed or the speed is 0, and the braking is gradually completed.

Before detecting the fan speed when the fan rotates against the wind, it also includes: estimating the headwind speed through the state observer to determine whether the motor is reversed; when the motor is reversed, trigger the detection of the fan speed when the fan rotates against the wind; start up. Estimate the headwind speed through the state observer, and determine whether to reverse: 1: The motor does not reverse, it is in a static state, and directly enters the forward start; Case 2: The motor reverses, and then the detected speed is divided into high-speed, medium There are three grades of high speed and low speed, and the optimal braking method is performed according to different headwind speed grades.

In the above embodiment, after the reverse rotation of the motor is detected, the reverse rotation speed is divided into three levels: high speed, medium speed, and low speed, and the optimal braking method is performed according to different headwind speed levels, and the braking mode implemented in the medium speed section In the dynamic mode, the duty cycle of the lower bridge arm is variable, and the value of the duty cycle can be adjusted according to different motors and inverters, so that the fan can be started safely and reliably under headwind conditions.

In the preferred embodiment 1 of the present invention, another fan startup control method is also provided. Specifically, FIG. 3 shows an optional flow chart of the method. As shown in FIG. 3, the method includes the following steps S301-S310:

S301: standby;

S302: Detect whether it is turned on, if yes, enter step S303, otherwise, return to step S301;

S303: Determine whether to reverse, if yes, go to step S304, otherwise, go to step S309;

S304: Judging whether the rotational speed ≥ high speed is established, if yes, go to step S305, otherwise, go to step S306;

S305: U-phase and V-phase commutation control, enter closed-loop braking and decelerate to below high speed, then return to continue to execute step S304;

S306: Judging whether the rotational speed ≥ medium speed is established, if yes, proceed to step S307, otherwise, proceed to step S308;

S307: The three-phase upper bridge arm is fully closed, and the three-phase lower bridge arm acts according to a 30% duty cycle, enters the buffer short-circuit braking state, and then returns to continue to execute step S306;

S308: The three-phase upper bridge arm is fully closed, the three-phase lower bridge arm is fully open, and enters the full short-circuit braking state;

S309: forward start state;

S310: Enter the running state.

Through the division of headwind speed levels, different headwind speeds correspond to optimal braking measures, and the present invention can solve the problems of difficult start-up and poor start-up reliability of outdoor fans of air conditioners in headwind environments in the prior art, such as inaccurate low-speed observation by the state observer As a result, the reverse braking of the wind turbine is not thorough, unreliable and difficult to start successfully, and the high current damage to the inverter and motor occurs during the high-speed reverse braking of the wind turbine, which effectively improves the reliability and stability of the wind turbine starting against the wind sex.

Example 2

Based on the fan startup control method provided in the above-mentioned embodiment 1, a fan startup control device is also provided in the preferred embodiment 2 of the present invention. Specifically, FIG. 4 shows an optional structural block diagram of the device. As shown in Figure 4, the device includes:

The detection module 402 is used to detect the fan speed when the fan rotates against the wind;

The determination module 404 is connected with the detection module 402, and is used to determine the braking mode of the motor according to the fan speed, and perform braking according to the braking mode;

The starting module 406 is connected with the determining module 404, and is used to determine whether the braking is completed, and control the fan to start forward after the braking is completed.

In the above-mentioned embodiment, a reliable starting scheme of the fan is provided. When the wind blows against the wind, the rotation speed of the fan is detected to determine the corresponding braking mode of the motor for braking, and the fan is controlled to start in the forward direction after the braking is completed. In the above scheme, the corresponding optimal braking scheme is adopted for different fan speeds, and the difficulty in starting the fan at different headwind speeds is specifically solved. For example, it is difficult to determine the rotor position and speed information at the low speed stage, which leads to incomplete reverse braking of the fan. , Unreliable and difficult to start successfully, and the large current during the reverse braking process in the high-speed stage will damage the inverter and motor, etc., to achieve reliable and successful start while protecting the inverter and motor under headwind conditions.

The determination module 404 includes: a speed determination sub-module for determining the speed level corresponding to the fan speed; wherein the speed level includes at least high speed, medium speed and low speed; a braking determination sub-module for determining the braking method according to the speed level.

The brake determination submodule includes:

The first braking unit is used to control the U-phase and V-phase commutation of the stator winding of the motor when the speed level is high-speed; after the U-phase and V-phase commutation, obtain the position and speed information of the rotor, according to the rotor The position and speed information control the motor to enter closed-loop braking.

The second braking unit is used to control all the three-phase upper bridge arms of the inverter to be turned off and reduce the duty cycle of the three-phase lower bridge arms when the rotational speed level is medium.

The third braking unit is used to control all three-phase upper bridge arms of the inverter to be turned off and control all three-phase lower bridge arms to be turned on when the speed level is low.

The starting module 406 includes: a judging submodule, used to re-detect the fan speed after a preset time, and judge whether the fan speed is less than a preset threshold; a first determination submodule, used to determine whether the fan speed is less than a preset threshold; braking; the second determining submodule is used for otherwise, determining that the braking has not been completed. And, the re-detection sub-module is used to determine the braking mode of the motor according to the re-detected fan speed when it is determined that the braking is not completed, and perform braking according to the braking mode until the braking is completed.

The device also includes: a reverse module, which is used to estimate the headwind speed through a state observer before detecting the fan speed when the fan rotates against the wind, and determine whether the motor is reversed; a trigger module, which is used to trigger and detect the fan when the motor is reversed. The fan speed when it rotates against the wind; the control module is used to control the fan to start in the forward direction otherwise.

With regard to the apparatus in the foregoing embodiments, the specific manner in which each unit and module executes operations has been described in detail in the embodiments related to the method, and will not be described in detail here.

Example 3

Based on the fan start-up control device provided in the above-mentioned embodiment 2, an air-conditioning unit is also provided in preferred embodiment 3 of the present invention, the external unit of the air-conditioner unit adopts the above-mentioned fan start-up control device.

In the above-mentioned embodiment, a reliable starting scheme of the fan is provided. When the wind blows against the wind, the rotation speed of the fan is detected to determine the corresponding braking mode of the motor for braking, and the fan is controlled to start in the forward direction after the braking is completed. In the above scheme, the corresponding optimal braking scheme is adopted for different fan speeds, and the difficulty in starting the fan at different headwind speeds is specifically solved. For example, it is difficult to determine the rotor position and speed information at the low speed stage, which leads to incomplete reverse braking of the fan. , Unreliable and difficult to start successfully, and the large current during the reverse braking process in the high-speed stage will damage the inverter and motor, etc., to achieve reliable and successful start while protecting the inverter and motor under headwind conditions.

Example 4

Based on the fan start-up control method provided in Embodiment 1 above, in preferred Embodiment 4 of the present invention, a storage medium containing computer-executable instructions is also provided, and the computer-executable instructions are executed by a computer processor using In order to implement the fan start-up control method as described above.

In the above-mentioned embodiment, a reliable starting scheme of the fan is provided. When the wind blows against the wind, the rotation speed of the fan is detected to determine the corresponding braking mode of the motor for braking, and the fan is controlled to start in the forward direction after the braking is completed. In the above scheme, the corresponding optimal braking scheme is adopted for different fan speeds, and the difficulty in starting the fan at different headwind speeds is specifically solved. For example, it is difficult to determine the rotor position and speed information at the low speed stage, which leads to incomplete reverse braking of the fan. , Unreliable and difficult to start successfully, and the large current during the reverse braking process in the high-speed stage will damage the inverter and motor, etc., to achieve reliable and successful start while protecting the inverter and motor under headwind conditions.

Other embodiments of the invention will be readily apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the present invention, these modifications, uses or adaptations follow the general principles of the present invention and include common knowledge or conventional technical means in the technical field not invented by the present invention . The specification and examples are to be considered exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

It should be understood that the present invention is not limited to the precise constructions which have been described above and shown in the accompanying drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the invention is limited only by the appended claims.

Claims (11)

1. A fan startup control method, characterized in that, comprising: Detect the fan speed when the fan rotates against the wind; Determine the braking mode of the motor according to the speed of the fan, and perform braking according to the braking mode; Determine whether the braking is completed, and control the fan to start forward after the braking is completed. 2. The method according to claim 1, wherein determining the braking mode of the motor according to the fan speed comprises: Determine the speed level corresponding to the speed of the fan; wherein, the speed level at least includes: high speed, medium speed and low speed; The braking mode is determined according to the speed level. 3. The method according to claim 2, wherein when the speed level is the high speed, determining the braking method according to the speed level comprises: Controlling the U-phase and V-phase of the stator winding of the motor to commutate; After the U-phase and V-phase are commutated, the position and speed information of the rotor is obtained, and the motor is controlled to enter closed-loop braking according to the position and speed information of the rotor. 4. The method according to claim 2, wherein when the speed level is the medium speed, determining the braking method according to the speed level comprises: All the three-phase upper bridge arms of the inverter are controlled to be turned off, and the duty cycle of the three-phase lower bridge arms is reduced. 5. The method according to claim 2, wherein when the speed level is the low speed, determining the braking method according to the speed level comprises: All three-phase upper bridge arms of the inverter are controlled to be turned off, and all three-phase lower bridge arms are controlled to be turned on. 6. The method of claim 1, wherein determining whether braking is complete comprises: After a preset time, re-detect the fan speed to determine whether the fan speed is less than a preset threshold; When the speed of the fan is less than the preset threshold, it is determined that braking is completed; Otherwise, it is determined that braking is not done. 7. The method according to claim 6, further comprising: When it is determined that the braking has not been completed, the braking mode of the motor is determined according to the re-detected rotational speed of the fan, and the braking is performed according to the braking mode until the braking is completed. 8. The method according to claim 1, further comprising: before the detection of the fan speed when the fan rotates against the wind: Estimating the headwind speed through a state observer to determine whether the motor is reversed; When the motor reverses, trigger the detection of the fan speed when the fan rotates against the wind; Otherwise, control the fan to start forward. 9. A fan start control device, characterized in that it comprises: The detection module is used to detect the fan speed when the fan rotates against the wind; A determination module, configured to determine the braking mode of the motor according to the fan speed, and perform braking according to the braking mode; The starting module is used to determine whether the braking is completed, and control the fan to start in the forward direction after the braking is completed. 10. An air-conditioning unit, characterized in that the external unit of the air-conditioning unit adopts the fan startup control device according to claim 9. 11. A storage medium containing computer-executable instructions, wherein the computer-executable instructions are used to execute the fan start-up control method according to any one of claims 1 to 8 when executed by a computer processor .

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