Plasma power supplies and coating equipment

Abstract

This utility model relates to a plasma power supply and a coating equipment. The plasma power supply provided by this utility model powers an inductive load and includes: a first DC voltage source, a DC chopper circuit, a bias circuit, a first output control circuit, and a first freewheeling circuit. The plasma power supply provided by this utility model has the ability to adapt to the abrupt changes in plasma load characteristics at the nanosecond level. Especially when operating under inductive load conditions, it can effectively reduce the voltage stress on the switching transistor, protect the switching transistor of the plasma power supply, reduce the risk of arcing, and improve the coating quality.

Description

Technical Field

[0001] This utility model relates to the field of high-power power supply technology, and in particular to a plasma power supply and coating equipment. Background Technology

[0002] With industrial development, the requirements for material surface properties are becoming increasingly stringent, such as wear resistance, corrosion resistance, and conductivity. Traditional methods are insufficient to meet these demands, thus necessitating new surface treatment technologies. Plasma coating technology, characterized by high adhesion, good uniformity, high quality, multifunctionality, and environmental friendliness, has been widely applied in semiconductor, photovoltaic, and other fields. The key to plasma coating technology lies in the plasma power supply; its output characteristics directly determine the coating quality.

[0003] In this technology, due to the complex internal environment of the plasma coating chamber and the rapid change rate of the plasma load, typically at the nanosecond (ns) level, the plasma power supply is required to have a fast load response speed.

[0004] However, the current load response speed of plasma power supplies cannot meet the requirements of plasma load change speed, making the internal switching transistors of the plasma power supply susceptible to damage, thus affecting the coating quality and performance. Especially when long output cables are used in the coating site, causing the plasma power supply to operate under a large inductive load, the inductive load will induce high voltage to maintain the load current, leading to increased voltage stress on the internal switching transistors of the plasma power supply and generating high-voltage arcs. This makes the internal switching transistors of the plasma power supply susceptible to damage, resulting in poor coating quality and performance. Utility Model Content

[0005] This invention provides a plasma power supply and coating equipment to improve the quality and performance of coatings.

[0006] In a first aspect, this utility model provides a plasma power supply, which powers an inductive load. The plasma power supply includes a forward circuit, comprising: a first DC voltage source, a DC chopper circuit, a bias circuit, a first output control circuit, and a first freewheeling circuit. The positive output terminal of the first DC voltage source is connected to the first input terminal of the DC chopper circuit, and the negative output terminal of the first DC voltage source is connected to the second input terminal of the DC chopper circuit and the first terminal of the first freewheeling circuit. The first terminal of the bias circuit is connected to the first output terminal of the DC chopper circuit and the first terminal of the first output control circuit. The second terminal of the bias circuit is connected to the... The second output terminal of the DC chopper circuit, the second terminal of the first freewheeling circuit, and the first terminal of the inductive load are connected. The second terminal of the first output control circuit is connected to the third terminal of the first freewheeling circuit and the second terminal of the inductive load. The fourth terminal of the first freewheeling circuit is connected to the third output terminal of the DC chopper circuit. The DC chopper circuit is used to adjust the voltage of the signal output by the first DC voltage source. The bias circuit is used to reduce the ripple of the signal output by the DC chopper circuit. The first output control circuit is used to adjust the waveform of the signal output by the bias circuit. The first freewheeling circuit is used to provide a low-impedance freewheeling loop for the inductive load.

[0007] In conjunction with the first aspect, in one possible implementation, the bias circuit includes a switching transistor Q1, a capacitor C1, a diode D1, and an inductor L1; the source of the switching transistor Q1 is connected to the first output terminal of the DC chopper circuit and the first terminal of the first output control circuit; the drain of the switching transistor Q1 is connected to one end of the capacitor C1; the other end of the capacitor C1 is connected to the anode of the diode D1; the cathode of the diode D1 is connected to the second output terminal of the DC chopper circuit, the second terminal of the first freewheeling circuit, and the first terminal of the inductive load; the inductor L1 is connected in parallel with the diode D1; the bias circuit is used to enable the capacitor C1 to output a stable voltage source by turning the switching transistor Q1 on or off, thereby reducing the ripple of the signal output by the DC chopper circuit.

[0008] In conjunction with the first aspect, in one possible implementation, the first output control circuit includes a switching transistor Q2; the collector of the switching transistor Q2 is connected to a first terminal of the bias circuit, and the emitter of the switching transistor Q2 is connected to a third terminal of the first freewheeling circuit and a second terminal of the inductive load; the first output control circuit is used to adjust the waveform of the signal output by the bias circuit by turning the switching transistor Q2 on or off.

[0009] In conjunction with the first aspect, in one possible implementation, the first freewheeling circuit includes diodes D2, D3, and D4; the anode of diode D2 is connected to the negative output terminal of the first DC voltage source, the cathode of diode D2 is connected to the anodes of diodes D3 and D4, and the third output terminal of the DC chopper circuit, the cathode of diode D3 is connected to the second terminal of the bias circuit, and the cathode of diode D4 is connected to the second terminal of the first output control circuit.

[0010] In conjunction with the first aspect, in one possible implementation, the plasma power supply further includes: a reverse circuit, which comprises a second DC voltage source, a second output control circuit, and a second freewheeling circuit; the positive output terminal of the second DC voltage source is connected to a first terminal of the second output control circuit, the negative output terminal of the second DC voltage source is connected to a second terminal of the first output control circuit, the second terminal of the second output control circuit is connected to a second terminal of the bias circuit, and the second freewheeling circuit is connected in parallel with the second output control circuit; the second output control circuit is used to adjust the waveform of the signal output by the second DC voltage source; and the second freewheeling circuit is used to provide a low-impedance freewheeling loop for the inductive load.

[0011] In conjunction with the first aspect, in one possible implementation, the second output control circuit includes a switching transistor Q3; the collector of the switching transistor Q3 is connected to the positive output terminal of the second DC voltage source, and the emitter of the switching transistor Q3 is connected to the second terminal of the bias circuit; the second output control circuit is used to adjust the waveform of the signal output by the second DC voltage source by turning the switching transistor Q3 on or off.

[0012] In conjunction with the first aspect, in one possible implementation, the second freewheeling circuit includes a diode D5, a capacitor C2, and a resistor R1; the anode of the diode D5 is connected to a first terminal of the second output control circuit, the cathode of the diode D5 is connected to one end of the capacitor C2, the other end of the capacitor C2 is connected to a second terminal of the second output control circuit, and the resistor R1 and the capacitor C2 are connected in parallel.

[0013] In conjunction with the first aspect, in one possible implementation, the forward circuit further includes a first cutoff circuit, and the reverse circuit further includes a second cutoff circuit; a first terminal of the first cutoff circuit is connected to a second terminal of the bias circuit, a second terminal of the first cutoff circuit is connected to a first terminal of the second cutoff circuit, and a second terminal of the second cutoff circuit is connected to a second terminal of the second output control circuit; the first cutoff circuit is used to cut off the current flowing from the reverse circuit into the forward circuit; the second cutoff circuit is used to cut off the current flowing from the forward circuit into the reverse circuit.

[0014] In conjunction with the first aspect, in one possible implementation, the plasma power supply further includes a digital controller and a sampling circuit; the digital controller is connected to the first DC voltage source, the DC chopper circuit, the bias circuit, the first output control circuit, the second DC voltage source, the second output control circuit, and the sampling circuit; the sampling circuit is used to acquire the current and voltage of the inductive load and output the acquired current and voltage to the digital controller; the digital controller is used to receive the current and voltage from the sampling circuit and control the on and off of the first DC voltage source, the DC chopper circuit, the bias circuit, the first output control circuit, the second DC voltage source, and the second output control circuit based on the received current and voltage.

[0015] Secondly, this utility model provides a coating device, which includes a plasma power source as described in the first aspect or any implementation thereof.

[0016] This invention provides a plasma power supply and a coating apparatus. In the plasma power supply provided by this invention, a freewheeling circuit provides a low-impedance freewheeling path for the inductive load, thereby clamping the highest voltage of the inductive load at the voltage of the DC voltage source. This reduces the risk of high-voltage arcing induced by the inductive load damaging the internal switching transistors of the plasma power supply, thus improving the quality and performance of the coating. When the plasma power supply operates with an inductive load, the freewheeling circuit can maintain the continuity of the load current, thereby reducing the voltage stress on the internal switching transistors of the plasma power supply and helping to improve the plasma power supply's ability to adapt to nanosecond (ns) level plasma load characteristic abrupt changes. Furthermore, a DC chopper circuit is used to regulate the output voltage, and a bias circuit reduces the output voltage ripple, thereby improving the accuracy and waveform stability of the output voltage. An output control circuit adjusts the waveform of the output voltage to meet the coating requirements of different application scenarios. In addition, the plasma power supply provided by this invention can be modularly designed for different applications to reduce manufacturing costs and meet the coating needs of various industrial applications. Attached Figure Description

[0017] Figure 1 A schematic diagram of the topology of a plasma power source provided by this utility model;

[0018] Figure 2 A schematic diagram of another plasma power source topology provided by this utility model;

[0019] Figure 3 A schematic diagram of the inductive load freewheeling path during the dead time after the positive voltage output provided by this utility model;

[0020] Figure 4 A comparison waveform of the voltage across the first output control circuit before and after adding the first freewheeling circuit provided by this utility model;

[0021] Figure 5 A schematic diagram of the topology of another plasma power source provided by this utility model;

[0022] Figure 5a A schematic diagram of an asymmetric bipolar pulse signal provided by this utility model;

[0023] Figure 6 A schematic diagram of the topology of another plasma power source provided by this utility model;

[0024] Figure 7 A schematic diagram of the inductive load freewheeling path during the dead time after reverse voltage output provided by this utility model;

[0025] Figure 8 A comparison waveform of the voltage across the second output control circuit before and after adding the second freewheeling circuit provided by this utility model;

[0026] Figure 9 A schematic diagram of another plasma power source topology provided by this utility model;

[0027] Figure 10 A schematic diagram of the topology of another plasma power source provided by this utility model. Detailed Implementation

[0028] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0029] This invention provides a plasma power supply and a coating apparatus. The plasma power supply provided by this invention has the ability to adapt to abrupt changes in plasma load characteristics at the nanosecond (ns) level. Especially when operating under inductive load conditions, it can effectively reduce the voltage stress on the internal switching transistors of the plasma power supply, protect the switching transistors, reduce the risk of arcing, and improve coating quality. Furthermore, the plasma power supply provided by this invention can be modularly designed for different applications to reduce manufacturing costs and meet the coating requirements of various industrial applications.

[0030] The following is combined with Figures 1 to 10 The technical solution provided by this utility model will be described in detail below.

[0031] Figure 1 This is a schematic diagram of the topology of a plasma power source provided by this utility model. (See diagram below.) Figure 1 As shown, the plasma power supply 100 includes a first DC voltage source 101, a DC chopper circuit 102, a bias circuit 103, a first output control circuit 104, and a first freewheeling circuit 105. The plasma power supply is used to power inductive loads.

[0032] like Figure 1 As shown, the positive output terminal of the first DC voltage source 101 is connected to the first input terminal of the DC chopper circuit 102, the negative output terminal of the first DC voltage source 101 is connected to the second input terminal of the DC chopper circuit 102 and the first terminal of the first freewheeling circuit 105, the first terminal of the bias circuit 103 is connected to the first output terminal of the DC chopper circuit 102 and the first terminal of the first output control circuit 104, the second terminal of the bias circuit 103 is connected to the second output terminal of the DC chopper circuit 102, the second terminal of the first freewheeling circuit 105 and the first terminal of the inductive load, the second terminal of the first output control circuit 104 is connected to the third terminal of the first freewheeling circuit 105 and the second terminal of the inductive load, and the fourth terminal of the first freewheeling circuit 105 is connected to the third output terminal of the DC chopper circuit 102.

[0033] The first DC voltage source 101 is used to output DC voltage to the DC chopper circuit 102.

[0034] The DC chopper circuit 102 is used to receive the DC voltage from the first DC voltage source 101 and to output the adjusted DC voltage.

[0035] The bias circuit 103 is used to reduce the ripple of the signal output by the DC chopper circuit 102.

[0036] The first output control circuit 104 is used to adjust the waveform of the signal output by the bias circuit 103.

[0037] The first freewheeling circuit 105 is used to provide a low-impedance freewheeling loop for inductive loads to maintain the continuity of load current.

[0038] In the plasma power supply provided by this invention, a first freewheeling circuit provides a low-impedance freewheeling path for the inductive load, thereby clamping the highest voltage of the inductive load to the voltage of the first DC voltage source. This reduces the risk of high-voltage arcing induced by the inductive load damaging the internal switching transistors of the plasma power supply, thus improving the quality and performance of the coating. When the plasma power supply operates with an inductive load, the first freewheeling circuit can maintain the continuity of the load current, thereby reducing the voltage stress on the internal switching transistors of the plasma power supply and helping to improve the plasma power supply's ability to adapt to nanosecond-level plasma load characteristic abrupt changes. Furthermore, a DC chopper circuit is used to regulate the output voltage, and a bias circuit reduces the ripple of the output voltage, thereby improving the accuracy and waveform stability of the output voltage. A first output control circuit adjusts the waveform of the output voltage to meet the coating requirements of different application scenarios.

[0039] Figure 2 A schematic diagram of another plasma power source topology provided by this utility model. Figure 2 The plasma power supply shown is for Figure 1 The illustration shows examples of the bias circuit, first output control circuit, and first freewheeling circuit in the plasma power supply. It should be understood that... Figure 2 The plasma power source shown is merely an example and is not intended to limit the technical solution of this application.

[0040] like Figure 2 As shown, the bias circuit 103 includes a switching transistor Q1 and a capacitor C1. The source of the switching transistor Q1 is connected to the first output terminal of the DC chopper circuit 102 and the first terminal of the first output control circuit 104. The drain of the switching transistor Q1 is connected to the first terminal of the capacitor C1. The second terminal of the capacitor C1 is connected to the second output terminal of the DC chopper circuit 102, the second terminal of the first freewheeling circuit 105, and the first terminal of the inductive load. The capacitance of the capacitor C1 is greater than or equal to a preset threshold.

[0041] In this invention, the bias circuit 103 uses a series connection of a switching transistor Q1 and a large capacitor C1. By turning the switching transistor Q1 on and off, the capacitor C1 serves as a stable voltage source for external output, thereby reducing the ripple of the output voltage and improving the accuracy and stability of the output voltage waveform.

[0042] In one possible implementation, the bias circuit 103 further includes a diode D1 and an inductor L1. The anode of diode D1 is connected to the second terminal of capacitor C1, and the cathode of diode D1 is connected to the second output terminal of DC chopper circuit 102, the second terminal of first freewheeling circuit 105, and the first terminal of inductive load. Inductor L1 is connected in parallel with diode D1.

[0043] In this circuit, inductor L1 limits the current fluctuation when the load is short-circuited, providing time for protection operation to start and improving the reliability of the circuit. Diode D1 acts as a freewheeling circuit for inductor L1, thereby reducing the impact of the high voltage induced by inductor L1 on switch Q1 when it is quickly turned off, and improving the operational safety of switch Q1.

[0044] It should be understood that the first terminal of the bias circuit 103 can be the source of the switching transistor Q1, and the second terminal of the bias circuit 103 is the negative terminal of the diode D1.

[0045] like Figure 2 As shown, the first output control circuit 104 may include a switching transistor Q2. Figure 2 In this circuit, the switching transistor Q2 is an insulated-gate bipolar transistor (IGBT). The collector of switching transistor Q2 is connected to the first terminal of the bias circuit 103, and the emitter of switching transistor Q2 is connected to the second terminal of the inductive load and the third terminal of the first freewheeling circuit 105. In some implementations, switching transistor Q2 can be an NMOS transistor.

[0046] It should be understood that the first terminal of the first output control circuit 104 is the collector of the switching transistor Q2, and the second terminal is the emitter of the switching transistor Q2.

[0047] The first output control circuit 104 is used to adjust the waveform of the signal output by the bias circuit 103 by turning the switch Q2 on or off, or in other words, to switch the output mode by turning the switch Q2 on or off. For example, there is no output when the switch Q2 is off; a DC waveform is output when the switch Q2 is normally on; and a pulse waveform is output when the switch Q2 is in a high-frequency switching state, so as to meet the coating requirements of different application scenarios.

[0048] like Figure 2 As shown, the first freewheeling circuit 105 includes diodes D2, D3, and D4. The anode of diode D2 is connected to the negative output terminal of the first DC voltage source 101, the cathode of diode D2 is connected to the anodes of diodes D3 and D4, and the third output terminal of the DC chopper circuit 102, the cathode of diode D3 is connected to the second terminal of the bias circuit 103, and the cathode of diode D4 is connected to the second terminal of the first output control circuit 104.

[0049] It should be understood that the first terminal of the first freewheeling circuit 105 is the positive terminal of diode D2, the second terminal is the negative terminal of diode D3, the third terminal is the negative terminal of diode D4, and the fourth terminal is the negative terminal of diode D2.

[0050] Considering that the plasma chamber load is inductive, or that the plasma power supply load is inductive, during the off-state of the first DC voltage source 101, DC chopper circuit 102, and first output control circuit 104, because the inductive load current cannot change abruptly, in order to maintain the load current, the inductive load will generate a high induced voltage and thus an arc in a short period of time, thereby affecting the internal switching transistors of the plasma power supply. Therefore, this invention adds a first freewheeling circuit 105 at the input and load terminals. The first freewheeling circuit 105 uses diodes connected in series to connect the input and output, providing a low-impedance freewheeling path for the load inductance, thereby clamping the highest load voltage at the voltage of the first DC voltage source 101, so as to avoid the inductive load generating a high-voltage arc that affects the coating quality and damages the equipment, thereby achieving a rapid arc extinguishing effect.

[0051] For ease of understanding and description, considering Figure 1 and Figure 2 The circuit outputs a positive voltage because it can... Figure 1 and Figure 2 The circuit in the circuit is called the forward circuit, which means that the forward circuit includes a first DC voltage source 101, a DC chopper circuit 102, a bias circuit 103, a first output control circuit 104, and a first freewheeling circuit 105.

[0052] Figure 3 This is a schematic diagram of the inductive load freewheeling path during the dead time after the forward voltage output provided by this utility model. Figure 3 As shown, when the plasma chamber load is inductive, or when the plasma power supply load is inductive, during the period when the first output control circuit is turned off, the inductive load voltage is positive at the bottom and negative at the top, and freewheeling occurs as indicated by the arrows in the figure.

[0053] Figure 4 A comparison waveform of the voltage across the first output control circuit before and after adding the first freewheeling circuit provided by this utility model. For example... Figure 4 As shown, under the same operating conditions, if the first freewheeling circuit is not added, the inductive load will generate a high induced voltage in a short time, which will easily break down the first output control circuit. If the first freewheeling circuit is added to provide a low-impedance freewheeling loop for the inductive load, the highest voltage of the load can be clamped at the voltage of the first DC voltage source, avoiding the generation of high-voltage arcs by the inductive load, which will affect the coating quality and damage the equipment, thereby achieving the effect of rapid arc extinguishing.

[0054] According to actual test results, at an output power of 20 kilowatts (kW), the residual arc energy of the technical solution provided by this utility model is 2.25 megajoules (MJ), and the average residual arc energy is 0.11272 MJ / kW. The residual arc energy of existing coating power supplies is approximately 0.5 MJ / kW. Therefore, it can be considered that the technical solution provided by this utility model has a better control effect on residual arc energy and can achieve a better arc suppression effect, thereby improving coating quality and performance.

[0055] In one possible implementation, diodes D2, D3, and D4 can be replaced with switching transistors to enable the first freewheeling circuit 105 to have controllable freewheeling capability.

[0056] Figure 5 This is a schematic diagram of the topology of another plasma power source provided by this utility model. (See attached diagram.) Figure 5 As shown, the plasma power supply 100 also includes a second DC voltage source 111, a second output control circuit 112, and a second freewheeling circuit 113.

[0057] like Figure 5 As shown, the positive output terminal of the second DC voltage source 111 is connected to the first terminal of the second output control circuit 112, the negative output terminal of the second DC voltage source 111 is connected to the second terminal of the first output control circuit 104, the second terminal of the second output control circuit 112 is connected to the second terminal of the bias circuit 103, and the second freewheeling circuit 113 is connected in parallel with the second output control circuit 112.

[0058] The second DC voltage source 111 is used to output a voltage signal to the second output control circuit 112.

[0059] The second output control circuit 112 is used to receive a voltage signal from the second DC voltage source 111 and to adjust the output waveform of the voltage signal.

[0060] The second freewheeling circuit 113 is used to provide a low-impedance freewheeling loop for the inductive load to maintain the current continuity of the inductive load.

[0061] and Figure 1 and Figure 2 Compared to the circuit in the middle, Figure 5 The newly added circuit is used to output reverse voltage. For ease of understanding and differentiation, it can be... Figure 5 The newly added circuit is called the reverse circuit, which means that the reverse circuit includes a second DC voltage source 111, a second output control circuit 112, and a second freewheeling circuit 113.

[0062] In this invention, by adding a reverse circuit, the plasma power supply can output an asymmetric bipolar pulse signal to improve the coating quality. The asymmetric bipolar pulse signal output by the plasma power supply can include voltage and current signals, such as... Figure 5a As shown.

[0063] In one possible implementation, a DC-DC circuit can be connected in series between the second DC voltage source 111 and the second output control circuit 112 to achieve voltage amplitude conversion.

[0064] Figure 6 A schematic diagram of the topology of another plasma power source provided by this utility model. Figure 6 The plasma power supply shown is for Figure 5 The illustration shows examples of the second DC voltage source, second output control circuit, and second freewheeling circuit in the plasma power supply. It should be understood that... Figure 6 The plasma power source shown is merely an example and is not intended to limit the technical solution of this application.

[0065] like Figure 6 As shown, the second output control circuit 112 includes a switching transistor Q3. Figure 6 In this circuit, the switching transistor Q3 is an IGBT. The collector of the switching transistor Q3 is connected to the positive output terminal of the second DC voltage source 111, and the emitter of the switching transistor Q3 is connected to the second terminal of the bias circuit 103. In some implementations, the switching transistor Q3 can be an NMOS.

[0066] It should be understood that the first terminal of the second output control circuit 112 is the collector of the switching transistor Q3, and the second terminal is the emitter of the switching transistor Q3.

[0067] The second output control circuit 112 is used to adjust the waveform of the voltage signal output by the second DC voltage source 111 by turning the switch Q3 on or off, or in other words, to switch the output mode by turning the switch Q3 on or off. For example, there is no output when the switch Q3 is off; a DC waveform is output when the switch Q3 is normally on; and a pulse waveform is output when the switch Q3 is in a high-frequency switching state, so as to meet the coating requirements of different application scenarios.

[0068] like Figure 6 As shown, the second freewheeling circuit 113 includes a diode D5, a capacitor C2, and a resistor R1. The anode of diode D5 is connected to the first terminal of the second output control circuit 112, the cathode of diode D5 is connected to the first terminal of capacitor C2, the second terminal of capacitor C2 is connected to the second terminal of the second output control circuit 112, and resistor R1 is connected in parallel with capacitor C2. Resistor R1 has a relatively large impedance, for example, in the kiloohm (kΩ) range.

[0069] It should be understood that the first terminal of the second freewheeling circuit 113 is the positive terminal of diode D5, and the second terminal is the second terminal of capacitor C2.

[0070] In this invention, a second freewheeling circuit 113 is added across the second output control circuit 112. This provides a low-impedance freewheeling path for the inductive load during high-frequency output, preventing the inductive load from generating a high-voltage arc that could damage the switching transistor and improve the coating quality. Furthermore, diode D5, connected in series with capacitor C2, can discharge through resistor R1. Since resistor R1 has a relatively high impedance, this reduces the risk of the second freewheeling circuit 113 bypassing the second output control circuit 112.

[0071] Figure 7 This is a schematic diagram of the inductive load freewheeling path during the dead time after the reverse voltage output provided by this utility model. Figure 7 As shown, when the plasma chamber load is inductive, or when the plasma power supply load is inductive, during the period when the second output control circuit is turned off, the inductive load voltage is positive at the top and negative at the bottom, and freewheeling occurs as indicated by the arrows in the figure.

[0072] Figure 8 A comparison waveform of the voltage across the second output control circuit before and after adding the second freewheeling circuit provided by this utility model. (Example:) Figure 8 As shown, under the same operating conditions, without adding a second freewheeling circuit, the inductive load will generate a high induced voltage in a short time, which can easily break down the second output control circuit. If a second freewheeling circuit is added to provide a low-impedance freewheeling loop for the inductive load, the risk of the inductive load generating a high-voltage arc that affects the coating quality and damages the equipment can be reduced.

[0073] In one possible implementation, cutoff circuits can be added to both the forward and reverse circuits to allow them to operate independently, reducing interference between them. Figure 9 As shown.

[0074] See Figure 9 The forward circuit includes a first cutoff circuit 106, and the reverse circuit includes a second cutoff circuit 114.

[0075] The first terminal of the first cutoff circuit 106 is connected to the second terminal of the bias circuit 103, or in other words, the first terminal of the first cutoff circuit 106 is connected to the second terminal of the bias circuit 103, the second terminal of the first cutoff circuit 106 is connected to the first terminal of the second cutoff circuit 114, and the second terminal of the second cutoff circuit 114 is connected to the second terminal of the second output control circuit 112.

[0076] like Figure 9As shown, the first cutoff circuit 106 includes diode D6, and the second cutoff circuit 114 includes diode D7. The first terminal of the first cutoff circuit 106 is the cathode of diode D6, and the second terminal is the anode of diode D6. The first terminal of the second cutoff circuit 114 is the cathode of diode D7, and the second terminal is the anode of diode D7.

[0077] The first cutoff circuit 106 is used to cut off the current flowing from the reverse circuit into the forward circuit.

[0078] The second cutoff circuit 114 is used to cut off the current flowing from the forward circuit into the reverse circuit.

[0079] In one possible implementation, the plasma power supply 100 may further include a digital controller 120 and a sampling circuit 130, such as... Figure 10 As shown.

[0080] The digital controller 120 is connected to the first DC voltage source 101, the DC chopper circuit 102, the bias circuit 103, the first output control circuit 104, the second DC voltage source 111, the second output control circuit 112, and the sampling circuit 130.

[0081] The sampling circuit 130 is used to acquire the current and voltage of the inductive load and output the acquired current and voltage to the digital controller 120. It should be understood that the voltage of the inductive load can be understood as the output voltage of the plasma power supply, and the current of the inductive load can be understood as the output current of the plasma power supply.

[0082] In one possible implementation, the sampling circuit 130 includes a voltage sampling circuit and a current sampling circuit. The voltage sampling circuit is used to acquire the voltage of the inductive load. The current sampling circuit is used to acquire the current of the inductive load.

[0083] This application does not limit the specific implementation of the sampling circuit 130. For example, the sampling circuit 130 may include analog switches, operational amplifiers, sampling resistor networks, clamping protection circuits, filtering circuits, and digital-to-analog converters, etc.

[0084] The digital controller 120 receives current and voltage from the sampling circuit 130, and controls the DC chopper circuit 102, bias circuit 103, first output control circuit 104, and second output control circuit 112 to turn on or off based on the received current and voltage to achieve the output of the target signal. In other words, the digital controller 120 can control the DC chopper circuit 102, switching transistors Q1, Q2, and Q3 to turn on or off, achieving forward and reverse output of the output voltage. The switching states of switching transistors Q1 and Q2 can be consistent, while the switching states of switching transistors Q2 and Q3 can be opposite.

[0085] For example, when switching transistors Q1 and Q2 can be turned on or off based on a preset frequency, switching transistor Q3 can be turned off or on based on a preset frequency, thereby causing the plasma power supply output to be as follows: Figure 5a The asymmetric bipolar pulse signal shown improves the coating quality.

[0086] In this invention, considering that plasma coating technology uses a high-frequency power supply (such as a first DC voltage source 101 and a second DC voltage source 111) to provide stable energy, but the high-frequency power supply is easily affected by the internal environment of the plasma coating cavity during operation, resulting in large fluctuations in output voltage and output current, thus generating an electric arc. To address this type of arc, the digital controller 120 can control the conduction or cutoff of the first DC voltage source 101, DC chopper circuit 102, bias circuit 103, first output control circuit 104, second DC voltage source 111, and second output control circuit 112 based on the data collected by the sampling circuit 130, in order to reduce the output voltage and output current, thereby suppressing the generation of an electric arc and protecting the internal switching transistors of the plasma power supply.

[0087] For example, when the voltage or current sampled by the sampling circuit 130 increases, the digital controller 120 can detect an electric arc. If the arc detection threshold is exceeded, the controller can control the first DC voltage source 101, the DC chopper circuit 102, the bias circuit 103, the first output control circuit 104, the second DC voltage source 111, and the second output control circuit 112 to either turn on or off, thereby reducing the output voltage and current and suppressing arc generation. The arc detection threshold can be set according to actual needs, and this invention does not impose any limitations on it.

[0088] in addition, Figure 10 A schematic topology diagram of a DC chopper circuit 102 is also shown. It should be understood that this topology diagram is not intended to limit the technical solutions of this application. Figure 10 As shown, the DC chopper circuit 102 includes a buck circuit.

[0089] In this invention, the digital controller 120 can regulate the output voltage by controlling the on and off states of the switching transistors in the DC chopper circuit 102. Furthermore, the inductive reactance of the inductor in the step-down circuit of the DC chopper circuit 102 can be greater than or equal to a preset value, allowing the inductor to act as a stable current source, thereby reducing output current ripple and improving output current accuracy. The preset value can be set according to actual needs, and this invention does not impose any limitations on it.

[0090] In one possible implementation, the DC chopper circuit 102 may include multiple buck circuits, which can be connected in an interleaved parallel manner to reduce output current ripple, increase output power, and reduce device stress risk.

[0091] In one possible implementation, the plasma power supply can be modularly designed to expand the output voltage and current, thereby increasing the output power. For different applications, modular design can reduce manufacturing costs and meet the coating requirements of various industrial applications. For example, the forward circuit can be modularly designed, with multiple forward circuit modules connected in parallel for parallel output, or multiple forward circuit modules connected in parallel for series output. Similarly, the reverse circuit can be modularly designed, with multiple reverse circuit modules connected in parallel for parallel output, or multiple reverse circuit modules connected in parallel for series output. Furthermore, the plasma power supply can be modularly designed, with multiple plasma power supply modules connected in parallel for parallel output, or multiple plasma power supply modules connected in parallel for series output; this application does not impose any limitations on this approach.

[0092] This utility model also provides a coating device, including the plasma power supply shown in any of the foregoing embodiments.

[0093] In the description of this utility model, it should be noted that the terms "first", "second" and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0094] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. Furthermore, the technical features involved in the different embodiments of this utility model described above can be combined with each other as long as they do not conflict with each other.

[0095] It should be emphasized that the above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model in any way. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model shall still fall within the scope of the technical solution of the present utility model.

Claims

1. A plasma power supply, characterized by, The plasma power supply supplies power to an inductive load. The plasma power supply includes a forward circuit, which includes: a first DC voltage source, a DC chopper circuit, a bias circuit, a first output control circuit, and a first freewheeling circuit. The positive output terminal of the first DC voltage source is connected to the first input terminal of the DC chopper circuit, the negative output terminal of the first DC voltage source is connected to the second input terminal of the DC chopper circuit and the first terminal of the first freewheeling circuit, the first terminal of the bias circuit is connected to the first output terminal of the DC chopper circuit and the first terminal of the first output control circuit, the second terminal of the bias circuit is connected to the second output terminal of the DC chopper circuit, the second terminal of the first freewheeling circuit and the first terminal of the inductive load, the second terminal of the first output control circuit is connected to the third terminal of the first freewheeling circuit and the second terminal of the inductive load, and the fourth terminal of the first freewheeling circuit is connected to the third output terminal of the DC chopper circuit. The DC chopper circuit is used to adjust the voltage of the signal output by the first DC voltage source; The bias circuit is used to reduce the ripple of the signal output by the DC chopper circuit. The first output control circuit is used to adjust the waveform of the signal output by the bias circuit; The first freewheeling circuit is used to provide a low-impedance freewheeling loop for the inductive load.

2. The power supply of claim 1, wherein, The bias circuit includes a switching transistor Q1, a capacitor C1, a diode D1, and an inductor L1. The source of the switching transistor Q1 is connected to the first output terminal of the DC chopper circuit and the first terminal of the first output control circuit. The drain of the switching transistor Q1 is connected to one end of the capacitor C1. The other end of the capacitor C1 is connected to the positive terminal of the diode D1. The negative terminal of the diode D1 is connected to the second output terminal of the DC chopper circuit, the second terminal of the first freewheeling circuit, and the first terminal of the inductive load. The inductor L1 is connected in parallel with the diode D1. The bias circuit is used to enable the capacitor C1 to output a stable voltage source by turning the switch Q1 on or off, thereby reducing the ripple of the signal output by the DC chopper circuit.

3. The power supply of claim 1, wherein, The first output control circuit includes a switching transistor Q2; The collector of the switching transistor Q2 is connected to the first terminal of the bias circuit, and the emitter of the switching transistor Q2 is connected to the third terminal of the first freewheeling circuit and the second terminal of the inductive load. The first output control circuit is used to adjust the waveform of the signal output by the bias circuit by turning the switch Q2 on or off.

4. The power supply of claim 1, wherein, The first freewheeling circuit includes diode D2, diode D3 and diode D4; The positive terminal of diode D2 is connected to the negative output terminal of the first DC voltage source. The negative terminal of diode D2 is connected to the positive terminals of diode D3 and D4, as well as the third output terminal of the DC chopper circuit. The negative terminal of diode D3 is connected to the second terminal of the bias circuit. The negative terminal of diode D4 is connected to the second terminal of the first output control circuit.

5. The plasma power supply of any one of claims 1 to 4, wherein, The plasma power supply further includes: a reverse circuit, which includes a second DC voltage source, a second output control circuit, and a second freewheeling circuit; The positive output terminal of the second DC voltage source is connected to the first terminal of the second output control circuit, the negative output terminal of the second DC voltage source is connected to the second terminal of the first output control circuit, the second terminal of the second output control circuit is connected to the second terminal of the bias circuit, and the second freewheeling circuit is connected in parallel with the second output control circuit. The second output control circuit is used to adjust the waveform of the signal output by the second DC voltage source; The second freewheeling circuit is used to provide a low-impedance freewheeling loop for the inductive load.

6. The power supply of claim 5, wherein, The second output control circuit includes a switching transistor Q3; The collector of the switching transistor Q3 is connected to the positive output terminal of the second DC voltage source, and the emitter of the switching transistor Q3 is connected to the second terminal of the bias circuit. The second output control circuit is used to adjust the waveform of the signal output by the second DC voltage source by turning the switch Q3 on or off.

7. The plasma power supply according to claim 5, characterized in that, The second freewheeling circuit includes diode D5, capacitor C2 and resistor R1; The positive terminal of diode D5 is connected to the first terminal of the second output control circuit, the negative terminal of diode D5 is connected to one end of capacitor C2, the other end of capacitor C2 is connected to the second terminal of the second output control circuit, and resistor R1 and capacitor C2 are connected in parallel.

8. The plasma power supply according to claim 5, characterized in that, The forward circuit further includes a first cutoff circuit, and the reverse circuit further includes a second cutoff circuit; The first terminal of the first cutoff circuit is connected to the second terminal of the bias circuit, the second terminal of the first cutoff circuit is connected to the first terminal of the second cutoff circuit, and the second terminal of the second cutoff circuit is connected to the second terminal of the second output control circuit. The first cutoff circuit is used to cut off the current flowing from the reverse circuit into the forward circuit; The second cutoff circuit is used to cut off the current flowing from the forward circuit into the reverse circuit.

9. The plasma power supply according to claim 5, characterized in that, The plasma power supply also includes a digital controller and a sampling circuit; The digital controller is connected to the first DC voltage source, the DC chopper circuit, the bias circuit, the first output control circuit, the second DC voltage source, the second output control circuit, and the sampling circuit. The sampling circuit is used to acquire the current and voltage of the inductive load, and to output the acquired current and voltage to the digital controller. The digital controller is configured to receive current and voltage from the sampling circuit, and control the on and off of the first DC voltage source, the DC chopper circuit, the bias circuit, the first output control circuit, the second DC voltage source, and the second output control circuit based on the received current and voltage.

10. A coating apparatus, characterized in that, Including the plasma power source as described in any one of claims 1 to 9.

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