Controller, control method and system for stable high-voltage output of electrostatic spray gun

Abstract

The invention provides a controller, a control method and a system for stable high-voltage output of an electrostatic spray gun. The control method comprises a constant-power output mode and a micro-current output mode. Whether the target current value is smaller than a set threshold value or not is judged, and if not, a constant-power output mode is operated; if yes, running a micro-current output mode; the micro-current output mode is provided with an output current constant current control algorithm module, and a sine pulse width modulation module and a current sampling module which are electrically connected; the sine pulse width modulation module is in signal connection with a high-voltage output module of the spray gun; the current sampling module sends sampling information to the output current constant current control algorithm module, and the output current constant current control algorithm module outputs an execution signal to the sine pulse width modulation module according to the sampling information and a target current value. And the sinusoidal pulse width modulation module generates a first sinusoidal signal and sends the signal to the high-voltage output module. The invention relates to a micro-current output control method which can realize stable output.

Description

Technical Field

[0001] The invention relates to the technical field of electrostatic powder spraying, and in particular to a controller, a control method and a system for a stable high-voltage output of an electrostatic spray gun. Background Art

[0002] With the continuous development of electrostatic powder spraying technology, the diversity of sprayed workpieces is becoming more and more abundant, and the shapes of sprayed workpieces are also showing an irregular and complex trend. Specifically, there are more right angles, grooves, gaps, and complex internal cavities on the workpieces. These elements can easily cause the sprayed workpieces to produce a Faraday cage effect.

[0003] However, the output current of the existing traditional spray gun high-voltage electrostatic output current control mode is relatively large, and the current adjustment range is large, which makes the powder carry a large charge. As a result, the powder sprayed by the spray gun is difficult to enter the complex-shaped parts of the spray workpiece and accumulates on the surface of the workpiece, making the coating prone to problems such as "fat edges" and "orange peel". Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a controller, a control method and a system for stable high-voltage output of an electrostatic spray gun, so as to solve the problem that the output current in the existing traditional spray gun high-voltage electrostatic output current control mode is large, the current adjustment range is large, the powder has a large charge, and the powder sprayed by the spray gun is difficult to enter the complex-shaped parts of the spray workpiece and accumulates on the surface of the workpiece, causing the coating to easily produce "fat edges" and "orange peel" problems.

[0005] In order to solve the above technical problems, the technical solution used in the present invention is:

[0006] The control method for stable high-voltage output of an electrostatic spray gun described in the present invention includes a constant power output mode and a micro-current output mode;

[0007] Determine whether the target current value is less than a set threshold value, if not, run the constant power output mode; if yes, run the micro current output mode;

[0008] The micro-current output mode is provided with an output current constant current control algorithm module, a sinusoidal pulse width modulation module and a current sampling module, wherein the sinusoidal pulse width modulation module is electrically connected to the current sampling module and is signal-connected to the high-voltage output module of the spray gun;

[0009] The current sampling module sends the acquired sampling information to the output current constant current control algorithm module, and the output current constant current control algorithm module outputs an execution signal to the sinusoidal pulse width modulation module according to the sampling information and the target current value, and the sinusoidal pulse width modulation module generates a first sinusoidal signal according to the execution signal and sends the first sinusoidal signal to the high-voltage output module.

[0010] Preferably, the set threshold is no greater than 11 μA.

[0011] Further preferably, the minimum adjustment range of the output current constant current control algorithm module is 0.1 μA.

[0012] Preferably, the sampling information includes the output current value of the sinusoidal pulse width modulation module.

[0013] Another control method for a stable high-voltage output of an electrostatic spray gun described in the present invention includes a constant-voltage output mode, wherein the constant-voltage output mode is provided with an output voltage constant-voltage control algorithm module, a voltage sampling module, and a sinusoidal pulse width modulation module as described in claim 1, wherein the sinusoidal pulse width modulation module is electrically connected to the voltage sampling module and is signal-connected to the high-voltage output module of the spray gun;

[0014] The voltage sampling module sends the acquired voltage sampling value to the output voltage constant voltage control algorithm module, and the output voltage constant voltage control algorithm module determines whether the voltage sampling value is consistent with the target voltage value. If so, it outputs a maintenance signal to the sinusoidal pulse width modulation module; if not, it outputs an adjustment signal to the sinusoidal pulse width modulation module, and the sinusoidal pulse width modulation module generates a second sinusoidal signal according to the adjustment signal and sends the second sinusoidal signal to the high voltage output module.

[0015] Another object of the present invention is to provide a controller for an electrostatic spray gun with stable high-voltage output, wherein the controller is preset with any one of the above-mentioned control methods for the electrostatic spray gun with stable high-voltage output, and the controller controls the spray gun to spray by running the control method.

[0016] Alternatively, a controller for stable high-voltage output of an electrostatic spray gun is provided, wherein the controller is preset with the above-mentioned control method for stable high-voltage output of an electrostatic spray gun including the constant voltage output mode and the micro-current output mode, and the controller controls the spray gun to spray by running the control method.

[0017] In addition, a control system for stable high-voltage output of an electrostatic spray gun is provided, comprising a spray gun provided with a high-voltage output module, and a controller for stable high-voltage output of an electrostatic spray gun as described above, wherein the spray gun is connected to the controller.

[0018] Compared with the prior art, the beneficial effects of the control method for stable high-voltage output of an electrostatic spray gun described in the present invention are mainly reflected in:

[0019] The micro-current output mode in the method of the present invention can be started when the target current value is less than the set threshold value, and can obtain sampling information from the sinusoidal pulse width modulation module in real time through the current sampling module. The output current constant current control algorithm module can output an execution signal to the sinusoidal pulse width modulation module according to the sampling information and the target current value, and the sinusoidal pulse width modulation module sends the first sinusoidal signal to the high-voltage output module according to the execution signal, thereby achieving constant output current, providing users with an effective micro-current output control method, and being able to achieve stable output, and avoiding the problem of large output current and large current adjustment range when using the ordinary constant power output mode under the requirements of micro-current electrostatic powder spraying, which makes the powder carry a large amount of charge, and solves the problem that the output current is large and the current adjustment range is large in the existing traditional spray gun high-voltage electrostatic output current control mode, which makes the powder carry a large amount of charge, resulting in the powder sprayed from the spray gun being difficult to enter the complex-shaped parts of the sprayed workpiece and accumulating on the surface of the workpiece, causing the coating to easily produce "fat edges" and "orange peel" problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and other purposes, features and advantages of the present invention will become more clear by more specific description of the preferred embodiments of the present invention shown in the accompanying drawings. The same reference numerals indicate the same parts in all the accompanying drawings, and the accompanying drawings are not deliberately scaled to the actual size, and the focus is on illustrating the main purpose of the present invention.

[0021] Figure 1 A schematic flow chart of a control method for stable high voltage output of an electrostatic spray gun provided in Embodiment 1 of the present invention;

[0022] Figure 2 A schematic flow chart of a control method for stable high voltage output of an electrostatic spray gun provided in Embodiment 2 of the present invention;

[0023] Figure 3 A schematic diagram of a control system for a stable high-voltage output of an electrostatic spray gun provided by an embodiment of the present invention;

[0024] Reference numerals: controller 1 , spray gun 2 . DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and implement it. However, the embodiments cited are not intended to limit the present invention. In the present embodiment, it should be understood that the orientations or positional relationships indicated by terms such as "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", and "outside" are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0026] It should be noted that when an element is considered to be "connected" to another element, it may be directly connected to the other element and integrated therewith, or there may be an intermediate element at the same time. The terms "installed", "one end", "the other end" and similar expressions used in the present invention are for illustrative purposes only.

[0027] Embodiment 1

[0028] This embodiment 1 provides a control method for a stable high voltage output of an electrostatic spray gun, such as Figure 1 As shown, it includes constant power output mode and micro current output mode;

[0029] Determine whether the target current value is less than a set threshold value. If not, run the constant power output mode; if yes, run the micro current output mode; wherein the set threshold value is preferably not greater than 11 μA;

[0030] The micro-current output mode is provided with an output current constant current control algorithm module, a sinusoidal pulse width modulation module and a current sampling module. The sinusoidal pulse width modulation module is electrically connected to the current sampling module and is signal-connected to the high-voltage output module of the spray gun 2;

[0031] The current sampling module sends the acquired sampling information to the output current constant current control algorithm module. The output current constant current control algorithm module outputs an execution signal to the sinusoidal pulse width modulation module according to the sampling information and the target current value. The sinusoidal pulse width modulation module generates a first sinusoidal signal according to the execution signal and sends the first sinusoidal signal to the high voltage output module.

[0032] The micro-current output mode in the method of this embodiment can be started when the target current value is less than the set threshold value, and can obtain sampling information from the sinusoidal pulse width modulation module in real time through the current sampling module. The output current constant current control algorithm module can output an execution signal to the sinusoidal pulse width modulation module according to the sampling information and the target current value. The sinusoidal pulse width modulation module sends a first sinusoidal signal to the high-voltage output module according to the execution signal, thereby achieving constant output current, providing users with an effective micro-current output control method, and being able to achieve stable output, and avoiding the problem of large output current and large current adjustment range when using an ordinary constant power output mode under the requirements of micro-current electrostatic powder spraying, which makes the powder carry a large amount of charge. It can solve the problem that the output current is large and the current adjustment range is large in the existing traditional spray gun high-voltage electrostatic output current control mode, which makes the powder carry a large amount of charge, resulting in the powder sprayed from the spray gun being difficult to enter the complex-shaped parts of the spray workpiece and accumulating on the surface of the workpiece, causing the coating to easily produce "fat edges" and "orange peel" problems.

[0033] It should be noted that the constant power output mode is an existing traditional electrostatic powder spraying method, which is a well-known technology in the field and will not be described in detail here; the output current constant current control algorithm module is a logic algorithm for controlling the output current to be constant. Those skilled in the art can form it based on the existing constant current algorithm with relatively easy adaptability and limited number of modifications; the sinusoidal pulse width modulation module uses sinusoidal pulse width modulation (SPWM) for width modulation to form a sinusoidal current output. This is a prior art and will not be described in detail here.

[0034] Among them, the sampling information includes the output current value of the sinusoidal pulse width modulation module. When the output current constant current control algorithm module performs data processing according to the sampling information and the target current value, it can be divided into a coarse adjustment stage and a fine adjustment stage. The coarse adjustment stage is to make a large adjustment based on the difference between the target current value and the output current value obtained by sampling. The adjustment accuracy is 1μA, and the output current value can be stabilized within the range of ±0.5μA of the target current value. After the coarse adjustment stage is completed, the fine adjustment stage is entered. The adjustment accuracy of the fine adjustment stage is 0.1μA, and the output current value can be stabilized within the range of ±0.3μA of the target current value. That is, the adjustment amplitude of the output current constant current control algorithm module can be as small as 0.1μA, with high accuracy, which can achieve precise control of the charge on the powder.

[0035] Embodiment 2

[0036] When the constant power output mode is used for spraying complex irregular shaped workpieces, especially when dealing with complex workpieces, workpiece cavities and close-range spraying, the output resistance will change, which will cause the high-voltage output voltage to drop and fluctuate, leading to problems such as poor powder charging and poor powder coating effect. Figure 2In the second embodiment shown, a constant voltage output mode is proposed. The constant voltage output mode is provided with an output voltage constant voltage control algorithm module, a voltage sampling module and a sinusoidal pulse width modulation module. The sinusoidal pulse width modulation module is electrically connected to the voltage sampling module and is signal-connected to the high-voltage output module of the spray gun 2. The sinusoidal pulse width modulation module in this second embodiment can be shared with the sinusoidal pulse width modulation module of the micro-current output mode in the first embodiment.

[0037] The voltage sampling module sends the acquired voltage sampling value to the output voltage constant voltage control algorithm module. The output voltage constant voltage control algorithm module determines whether the voltage sampling value is consistent with the target voltage value. If so, it outputs a maintenance signal to the sinusoidal pulse width modulation module to keep the output voltage unchanged. If not, it outputs an adjustment signal to the sinusoidal pulse width modulation module to adjust the output voltage to make it the same as the target voltage value. The sinusoidal pulse width modulation module generates a second sinusoidal signal according to the adjustment signal and sends the second sinusoidal signal to the high-voltage output module. When the constant voltage output mode in this embodiment is running, the output voltage can be kept stable through the coordinated processing of the voltage sampling module, the output voltage constant voltage control algorithm module and the sinusoidal pulse width modulation module, so that the output voltage of the high-voltage output module of the spray gun 2 is constant, which can improve the spraying effect in the spraying of complex workpieces, workpiece cavities, and close-range spraying situations, and can solve the above-mentioned problem of poor powder charging and poor powder coating effect caused by the drop and fluctuation of the high-voltage output voltage.

[0038] Based on the above-mentioned embodiment of a control method for stable high-voltage output of an electrostatic spray gun, a controller for stable high-voltage output of an electrostatic spray gun is also provided. The controller 1 in this embodiment is preset with a control method for stable high-voltage output of an electrostatic spray gun in any of the aforementioned embodiments, or is preset with a control method for stable high-voltage output of an electrostatic spray gun in embodiment one and its preferred embodiment and embodiment two at the same time. The controller 1 controls the spray gun 2 to spray by running the aforementioned control method.

[0039] Based on the above-mentioned controller for stable high-voltage output of an electrostatic spray gun, an embodiment of a control system for stable high-voltage output of an electrostatic spray gun is also provided, such as Figure 3 As shown, the spray gun 2 is provided with a high-voltage output module and the controller 1 for stable high-voltage output of an electrostatic spray gun as described above, and the spray gun 2 is connected to the controller 1. The control system of this embodiment can provide users with different operating mode options including a micro-current output mode and a constant voltage output mode. When spraying complex irregular workpieces, workpiece cavities or close-range spraying, the user can select one of the operating modes according to the spraying situation, which can ensure stable high-voltage output of the spray gun 2 during the spraying operation and good spraying effect.

[0040] In this specification, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0041] In the description of this specification, the description with reference to the terms "preferred embodiment", "further embodiment", "other embodiments" or "specific example" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0042] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A control method for stable high voltage output of an electrostatic spray gun, characterized in that: Including constant power output mode and micro current output mode; Determine whether the target current value is less than a set threshold value, if not, run the constant power output mode; if yes, run the micro current output mode; The micro-current output mode is provided with an output current constant current control algorithm module, a sinusoidal pulse width modulation module and a current sampling module, wherein the sinusoidal pulse width modulation module is electrically connected to the current sampling module and is signal-connected to the high-voltage output module of the spray gun; The current sampling module sends the acquired sampling information to the output current constant current control algorithm module, and the output current constant current control algorithm module outputs an execution signal to the sinusoidal pulse width modulation module according to the sampling information and the target current value, and the sinusoidal pulse width modulation module generates a first sinusoidal signal according to the execution signal and sends the first sinusoidal signal to the high-voltage output module.

2. The control method according to claim 1, characterized in that: The set threshold is no greater than 11 μA.

3. The control method according to claim 2, characterized in that: The minimum adjustment range of the output current constant current control algorithm module is 0.1 μA.

4. The control method according to claim 1, characterized in that: The sampling information includes the output current value of the sinusoidal pulse width modulation module.

5. A control method for stable high voltage output of an electrostatic spray gun, characterized in that: Including a constant voltage output mode, the constant voltage output mode is provided with an output voltage constant voltage control algorithm module, a voltage sampling module and a sinusoidal pulse width modulation module as claimed in claim 1, the sinusoidal pulse width modulation module is electrically connected to the voltage sampling module, and is signal-connected to the high voltage output module of the spray gun; The voltage sampling module sends the acquired voltage sampling value to the output voltage constant voltage control algorithm module, and the output voltage constant voltage control algorithm module determines whether the voltage sampling value is consistent with the target voltage value. If so, it outputs a maintenance signal to the sinusoidal pulse width modulation module; if not, it outputs an adjustment signal to the sinusoidal pulse width modulation module, and the sinusoidal pulse width modulation module generates a second sinusoidal signal according to the adjustment signal and sends the second sinusoidal signal to the high voltage output module.

6. A controller for stable high voltage output of an electrostatic spray gun, characterized by: The controller is preset with a control method for stable high-voltage output of an electrostatic spray gun according to any one of claims 1 to 5, and the controller controls the spray gun to spray by running the control method.

7. A controller for stable high voltage output of an electrostatic spray gun, characterized in that: The controller is preset with a control method for stable high-voltage output of an electrostatic spray gun as claimed in claim 5 and any one of claims 1 to 4, and the controller controls the spray gun to spray by running the control method as claimed in claim 5 or any one of claims 1 to 4.

8. A control system for stable high-voltage output of an electrostatic spray gun, comprising a spray gun, wherein the spray gun is provided with a high-voltage output module, characterized in that: It also includes a controller for stable high-voltage output of an electrostatic spray gun as described in claim 6 or 7, and the spray gun is connected to the controller.

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