A control method for an electrically powered damper

Abstract

The application discloses a control method of an electrically-operated air door. The method comprises the following steps: obtaining a single-step pulse time Tk of the electrically-operated air door according to data of the electrically-operated air door of a refrigerator; selecting a carrier frequency fc used for chopping and calculating a period Tc according to the carrier frequency; setting a duty ratio sequence ds used for chopping based on a sine function; and controlling a level output of the electrically-operated air door at a switching time by using the duty ratio sequence ds. The application modulates the current by using the pulse width modulation technology at the level switching time, so that the current is smoothly raised, the oscillation is reduced, the smoothness of the current at the switching time is controlled, the oscillation of the stepping motor is reduced, and the purpose of reducing the noise is achieved.

Description

Technical Field

[0001] This invention belongs to the field of refrigerator control technology, and in particular relates to a control method for an electric damper. Background Technology

[0002] Currently, in refrigerators using electric dampers, the drive motor is typically a four-phase, four-step stepper motor. The forward and reverse rotation of the electric damper is controlled by adjusting the phase sequence. Control is generally achieved by assigning a high-level signal to the corresponding port. Due to the electrical and mechanical characteristics of the electric damper, it is prone to vibration during phase changes. Because its kinetic energy is relatively low, this vibration is often not manifested as overall refrigerator vibration but rather as noise that is perceived.

[0003] Regarding noise, on the one hand, due to the improvement of modern living environment, the human body's tolerance for noise from various electrical appliances has further decreased, especially for motors like refrigerators that run for a long time; on the other hand, due to the continuous competition among major refrigerator manufacturers, the noise of current high-end refrigerators, apart from the relatively obvious compressor noise and the sound of the refrigerant flowing in the system during the initial startup phase, is most noticeable from the 'click' sound of the electric damper during the stable cooling phase.

[0004] Because the existing control method uses direct switching between high and low levels, this often results in large oscillations in the current. These oscillations cause significant vibrations in the stepper motor, which is the biggest source of noise.

[0005] To solve this problem, a control method for an electric damper is now designed. Summary of the Invention

[0006] The purpose of this invention is to provide a control method for an electric damper. By using pulse width modulation technology to modulate the current during level switching, the current rises smoothly, reducing oscillations and controlling the smoothness of current switching, thereby reducing the oscillation of the stepper motor and solving the noise problem.

[0007] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0008] This invention relates to a control method for an electric damper, comprising the following steps:

[0009] Stp1: Obtain the single-step pulse time Tk of the electric damper based on the data of the refrigerator's electric damper;

[0010] Stp2, Select the carrier frequency fc used for chopping, and calculate the period Tc based on the carrier frequency;

[0011] Stp3. Based on the sine function, set the duty cycle sequence ds for chopping, where ds = [15%, 45%, 70%, 90%];

[0012] Stp4 controls the level output when the electric damper switches using the duty cycle sequence ds.

[0013] Preferably, the level output control flow of the electric damper control signal in step Stp4 is as follows:

[0014] SS01: When the instruction level is low, output a low level.

[0015] SS02. After the command level changes from low to high, during the first few carrier times, square waves with modified duty cycles are output sequentially according to the duty cycle sequence ds.

[0016] SS03: After the duty cycle sequence is completed, output a high level and start timing;

[0017] SS04. When the timing reaches 2*(Tk-len(ds)*Tc), the output starts in reverse order of ds, that is, first output 90% duty cycle, then output 70% duty cycle, until the output is low level; a total of len(ds) square waves are output.

[0018] SS05. When the instruction level changes from high to low, output a low level.

[0019] SS06. Repeat steps SS01-SS05.

[0020] Preferably, in step SS04, len(ds) is the number of data items contained in ds.

[0021] Preferably, the single-step pulse time Tk is 3ms.

[0022] Preferably, the carrier frequency fc used for chopping is set to 5kHz, then Tc = 1 / fc = 200µs.

[0023] The present invention has the following beneficial effects:

[0024] This invention uses pulse width modulation (PWM) technology to modulate the current during level switching, thereby smoothing the current rise, reducing oscillation, and controlling the smoothness of current switching. This reduces the oscillation of the stepper motor and achieves the goal of reducing noise.

[0025] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 A flowchart of a control method for an electric damper according to the present invention;

[0028] Figure 2 This is the output waveform of one phase of the control level for the electric damper.

[0029] Figure 3 The four-phase output waveforms represent the control level of the electric damper.

[0030] Figure 4 This is the control level switching waveform for an existing electric damper. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Please see Figure 1 As shown, the present invention is a control method for an electric damper, comprising the following steps:

[0033] Stp1. Obtain the single-step pulse time Tk of the electric damper based on the data of the refrigerator electric damper. The single-step pulse time Tk is determined by the relevant specifications of the electric damper. In this embodiment, the single-step pulse time Tk can be set to 3ms.

[0034] Stp2, Select the carrier frequency fc used for chopping, and calculate the period Tc based on the carrier frequency; For ease of calculation, in this embodiment, the carrier frequency fc used for chopping is set to 5kHz, then Tc=1 / fc=200us;

[0035] Stp3. Based on the sine function, set the duty cycle sequence ds for chopping, where ds = [15%, 45%, 70%, 90%];

[0036] Stp4 controls the level output of the electric damper during switching using the duty cycle sequence ds. The level output control flow of the electric damper control signal is as follows:

[0037] SS01: When the instruction level is low, output a low level.

[0038] SS02. After the command level changes from low to high, during the first few carrier times, square waves with modified duty cycles are output sequentially according to the duty cycle sequence ds.

[0039] SS03: After the duty cycle sequence is completed, output a high level and start timing;

[0040] SS04. When the timing reaches 2*(Tk-len(ds)*Tc), the output starts in reverse order of ds, that is, first output 90% duty cycle, then output 70% duty cycle, until the output is low level; a total of len(ds) square waves are output, where len(ds) is the number of data contained in ds.

[0041] SS05. When the instruction level changes from high to low, output a low level.

[0042] SS06. Repeat steps SS01-SS05.

[0043] Example 1:

[0044] The existing control method uses direct switching between high and low levels, which often results in significant current oscillations (see...). Figure 4 This oscillation causes significant vibration in the stepper motor, which is the biggest source of noise.

[0045] Step Stp4 controls the level output of one phase of the electric damper power supply, and the output waveform is as follows: Figure 2 As shown; the level output control steps for the other three phases are the same as those in step Stp4, and the final output waveforms of the four phases are as follows. Figure 3 As shown, the level output is controlled by PWM to reduce the oscillation of the response current, improve the smoothness of switching, and achieve the purpose of reducing noise.

[0046] It is worth noting that the various units included in the above system embodiments are only divided according to functional logic, but are not limited to the above division, as long as the corresponding functions can be achieved; in addition, the specific names of each functional unit are only for easy differentiation and are not used to limit the scope of protection of the present invention.

[0047] Furthermore, those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware, and the corresponding program can be stored in a computer-readable storage medium, such as ROM / RAM, disk, or optical disk.

[0048] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A control method for an electric damper, characterized in that, Includes the following steps: Stp1: Obtain the single-step pulse time Tk of the electric damper based on the data of the refrigerator's electric damper; Stp2, Select the carrier frequency fc used for chopping, and calculate the period Tc based on the carrier frequency; Stp3. Based on the sine function, set the duty cycle sequence ds for chopping, where ds = [15%, 45%, 70%, 90%]. Stp4, Level output during electric damper switching controlled by duty cycle sequence ds; The level output control flow of the electric damper control signal in step Stp4 is as follows: SS01: When the instruction level is low, output a low level; SS02. After the command level changes from low to high, the duty cycle of the square wave is modified sequentially according to the duty cycle sequence ds during the first few carrier times. SS03: After the duty cycle sequence is completed, output a high level and start timing; SS04. When the timing reaches 2*(Tk-len(ds)*Tc), start outputting in reverse order of ds, that is, first outputting 90% duty cycle, then 70% duty cycle, until outputting low level; a total of len(ds) square waves are output. SS05. When the instruction level changes from high to low, output a low level. SS06. Repeat steps SS01-SS05; In step SS04, len(ds) is the number of data items contained in ds.

2. The control method for an electric damper according to claim 1, characterized in that, The single-step pulse time Tk is 3ms.

3. The control method for an electric damper according to claim 1, characterized in that, If the carrier frequency fc used for chopping is set to 5kHz, then Tc=1 / fc=200us.

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