WO2013117054A1

WO2013117054A1 - Pwm dc pulse circuit and coating circuit

Info

Publication number: WO2013117054A1
Application number: PCT/CN2012/074380
Authority: WO
Inventors: 张云安
Original assignee: 中兴通讯股份有限公司
Priority date: 2012-02-09
Filing date: 2012-04-19
Publication date: 2013-08-15
Also published as: CN103248263A; CN103248263B

Abstract

Provided are a PWM DC pulse circuit, a coating circuit and a method for using the coating circuit for coating. The circuit comprises a voltage-dividing capacitor circuit and a switch circuit which are respectively connected to the positive electrode and the negative electrode of a power supply (31) of the PWM DC pulse circuit. The voltage-dividing capacitor circuit comprises a first voltage-dividing capacitor circuit (32) and a second voltage-dividing capacitor circuit (33) which are connected in series. The switch circuit comprises a first switch circuit (35) and a second switch circuit (36) which are connected in series. The circuit also comprises an inductive circuit (34). One end of the inductive circuit (34) is respectively connected to the first voltage-dividing capacitor circuit (32) and the second voltage-dividing capacitor circuit (33). The other end of the inductive circuit (34) is respectively connected to the first switch circuit (35) and the second switch circuit (36). Both the first switch circuit (35) and the second switch circuit (36) are connected to the output end of a control circuit, and are used for being in a zero-voltage soft-switch state at the ON/OFF time. The circuit exerts the high-frequency switch characteristic of a switch circuit so that the output pulse frequency is significantly increased and then the coating quality of a coated workpiece is increased.

Description

PWM DC pulse circuit and coating circuit

Technical field

The invention belongs to the technical field of power electronic circuit design and manufacture, and particularly relates to a pulse width modulation (PWM) DC pulse circuit, a coating circuit and a coating method using the coating circuit.

Background technique

With the increasing demands on the aesthetics and durability of various IT products, the surface treatment of mobile terminals (such as mobile phones, data cards, netbooks, etc.) is increasingly requiring the use of various compounds. Film, separator, insulating film, dielectric film, etc. The vacuum coating has a series of advantages such as strong film layer, controllable film layer, high purity, no waste liquid, no pollution to the environment, coating on the surface of metal materials, and coating on the surface of non-metal materials. As shown in FIG. 1 , it is a schematic diagram of a vacuum coating system, which includes a pulse power source 11 and a process chamber 12 . The vacuum coating system places a 100-1000 Gauss powerful magnet behind the cathode target, and the vacuum chamber is filled with an inert gas (Ar) at a pressure of 0.1 to 10 Pa (pa) as a carrier for gas discharge. Under high pressure, atomic ionization becomes ions and electrons, generating a plasma glow discharge. During acceleration of the electrons into the substrate, the electrons are affected by the magnetic field perpendicular to the electric field, causing the electrons to deflect and be bound to the plasma near the target surface. In the body region, electrons travel along the target surface in a cycloidal manner, constantly colliding with atoms during motion, and ionizing a large amount of ions, so the plasma density in this region is high. After many collisions, the energy of the electrons gradually decreases, getting rid of the binding of the magnetic lines, and finally falls on the substrate, the vacuum chamber wall and the target anode. Under the action of high-voltage electric field, ions collide with the target and release energy, which causes the atoms on the surface of the target to absorb the kinetic energy of the ions and get out of the original lattice. The neutral target atoms escape the surface of the target and fly to the substrate. And depositing a film on the substrate. In the vacuum coating system process research, it is found that the power pulse output frequency is the most critical parameter affecting the quality of the workpiece coating. If the pulse frequency is too low, the arcing phenomenon is likely to occur during the processing, resulting in low production efficiency; in addition, the higher the pulse frequency, the higher the surface quality of the workpiece. 20KHz ~ 200KHz pulse frequency is recognized as the preferred working frequency for dielectric material deposition. It can provide stable arc-free working state during deposition, and can obtain thicker film layer. The film layer has good hooking property and high bonding strength with matrix. , high hardness, good thermal shock resistance, electrical insulation and corrosion resistance. At present, vacuum coating power supply topology research, whether it is insulated gate field effect transistor

(MOSFET) is also an insulated gate bipolar transistor (IGBT) or IGBT module, which usually works in a hard-switching state, so that the high-frequency switching characteristics of the power transistor cannot be utilized, limiting the power pulse output frequency (below 50KHz); The DC pulse power supply structure used in the existing vacuum coating system is as shown in FIG. 2, and includes a DC power supply 21, a MOSFET main power tube 22, a buffer circuit 23, and a load 24, which are sequentially provided for the PWM DC pulse circuit. The MOSFET main power transistor 22 is connected in parallel with the buffer circuit 23 and then in series with the load 24. The anode of the DC power source 21 is connected to the drain of the MOSFET main power tube 22 and the upper end of the buffer circuit 23, respectively, and the cathode of the DC power source 21 is connected to the lower end of the load 24. The DC pulse power supply operation is divided into two processes by the MOSFET main power tube 22 switch: the MOSFET main power tube 22 is turned on, the load 24 is obtained as the voltage of the DC power supply 21; the MOSFET main power tube 22 is turned off, and the load voltage is zero. In order to prevent the voltage spike of the MOSFET main power tube 22 from being hard-switched, it must be absorbed by the buffer circuit 23. The MOSFET main power tube 22 hard switching mode limits the increase of the pulse frequency (not exceeding 50KHz), resulting in low production efficiency. The coating film produces a surface layer of mobile terminal structural parts with good quality, easy wear and short service life.

Summary of the invention

Embodiments of the present invention provide a pulse width modulation (PWM) DC pulse circuit, a coating circuit, and a coating circuit for coating, to overcome the disadvantages of low productivity of the vacuum coating power supply and general quality of the coated film.

In order to solve the above technical problem, the following technical solutions are used in the embodiment of the present invention:

A pulse width modulation (PWM) DC pulse circuit, the PWM DC pulse circuit comprising: a circuit and a switching circuit, the voltage dividing capacitor circuit comprises a first voltage dividing capacitor circuit and a second voltage dividing capacitor circuit connected in series, The switching circuit includes a first switching circuit and a second switching circuit connected in series; the PWM DC pulse circuit further includes an inductor circuit, one end of the inductor circuit and the first voltage dividing capacitor circuit and the second voltage dividing The capacitor circuits are all connected, the other end of the inductor circuit is connected to the first switch circuit and the second switch circuit; the first switch circuit and the second switch circuit are both connected to the output of the control circuit Connected, set to: at zero at switch time Voltage soft switching state.

Optionally, the first switching circuit and the second switching circuit are both transistors having high frequency operating characteristics.

Optionally, the transistor is an insulated gate field effect transistor (MOSFET), and the MOSFET comprises an N communication MOSFET and a P channel MOSFET, wherein:

When the MOSFET is the N-channel MOSFET, a drain of the MOSFET in the first switching circuit is connected to a positive pole of the power supply, and a gate of the MOSFET in the first switching circuit Connected to an output end of the control circuit, a source of the MOSFET in the second switch circuit is connected to a negative pole of the power supply, and a gate of the MOSFET in the second switch circuit is The output of the control circuit is connected;

When the MOSFET is the P-channel MOSFET, a source of the MOSFET in the first switching circuit is connected to a positive pole of the power supply, and a gate of the MOSFET in the first switching circuit Connected to an output of the control circuit, a drain of the MOSFET in the second switch circuit is connected to a negative pole of the power supply, and a gate of the MOSFET in the second switch circuit is The outputs of the control circuits are connected.

Alternatively, the MOSFET is a separate MOSFET transistor or a MOSFET module circuit formed by connecting MOSFET transistors in series or in parallel.

Optionally, the transistor is an insulated gate bipolar transistor (IGBT) or an IGBT module, and the collector of the IGBT or the IGBT module in the first switching circuit is connected to an anode of the power supply. a gate of the IGBT or the IGBT module in the first switching circuit is connected to an output end of the control circuit, and an emission level of the IGBT or the IGBT module in the second switching circuit is A negative pole of the power supply is connected, and the IGBT of the second switching circuit or the gate of the IGBT module is connected to an output of the control circuit.

Optionally, the IGBT or the IGBT module is a separate IGBT or IGBT module, or an IGBT module circuit formed by connecting multiple IGBTs or multiple IGBT modules in series or in parallel.

Optionally, the inductor circuit is an inductor; the inductor is configured to: resonate with the first switch circuit and the second switch circuit when the first switch circuit changes from an on state to an off state Passing the voltage of the second switching circuit to zero; or, the second switching circuit is turned on When the on state changes to the off state, resonance occurs with the first switching circuit and the second switching circuit to lower the voltage of the first switching circuit to zero.

Optionally, the first voltage dividing capacitor circuit is a first voltage dividing capacitor, the second voltage dividing capacitor circuit is a second voltage dividing capacitor, and a positive pole of the first voltage dividing capacitor and a positive pole of the power supply power source Connected, the negative pole of the second voltage dividing capacitor is connected to the negative pole of the power supply.

A coating circuit comprising a pulse width modulation (PWM) DC pulse circuit and a load connected to the PWM DC pulse circuit, wherein:

The PWM DC pulse circuit includes: a voltage dividing capacitor circuit and a switching circuit respectively connected to the positive and negative poles of the power supply source of the PWM DC pulse circuit, wherein the voltage dividing capacitor circuit comprises a first voltage dividing capacitor circuit connected in series And a second voltage dividing capacitor circuit, the switching circuit includes a first switching circuit and a second switching circuit connected in series; the coating circuit further includes an inductor circuit, one end of the inductor circuit and the first voltage dividing capacitor circuit And the second voltage dividing capacitor circuit is connected, the other end of the inductor circuit is connected to the first switch circuit and the second switch circuit; the first switch circuit and the second switch circuit, Both are connected to the output of the control circuit, and are both set to be in a zero voltage soft switching state at the time of switching; the load is connected in parallel with the second switching circuit.

Optionally, when the first switching circuit and the second switching circuit are both insulated gate field effect transistors (MOSFETs), the MOSFET includes an N communication MOSFET and a P-channel MOSFET; In the case of an N-channel MOSFET, a drain of the MOSFET in the first switching circuit is connected to a positive pole of the power supply, and a gate of the MOSFET in the first switching circuit and an output of the control circuit Connected to the end, the source of the MOSFET in the second switch circuit is connected to the negative pole of the power supply, and the gate of the MOSFET in the second switch circuit is connected to the output end of the control circuit; When the MOSFET is the P-channel MOSFET, a source of the MOSFET in the first switching circuit is connected to a positive pole of the power supply, and a gate of the MOSFET in the first switching circuit Connected to an output of the control circuit, a drain of the MOSFET in the second switch circuit is connected to a negative pole of the power supply, a gate of the MOSFET in the second switch circuit and the Output of the control circuit Connected; or

The first switching circuit and the second switching circuit are both insulated gate bipolar transistors (IGBTs) Or the IGBT module, the collector of the IGBT or the IGBT module in the first switching circuit is connected to the anode of the power supply, the IGBT of the first switching circuit or the IGBT module a gate is connected to an output end of the control circuit, and an emitter of the IGBT or the IGBT module in the second switch circuit is connected to a negative pole of the power supply, and the second switch circuit is An IGBT or a gate of the IGBT module is connected to an output of the control circuit.

Optionally, when the second switching circuit is the N-channel MOSFET, a structure in the load is connected to a drain of the MOSFET, and a coating material in the load is connected to the MOSFET source. ; or

When the second switching circuit is the IGBT or the IGBT module, a structural member in the load is connected to a collector of the IGBT or the IGBT module, a coating material in the load and the IGBT Or the emitters of the IGBT modules are connected.

A method for coating a film using any of the above-described circuits, the method comprising: the PWM DC pulse circuit supplying power to the load such that ions of a coating material in the load are plated under electromagnetic induction The process of powering the load by the PWM DC pulse circuit includes:

The first switch circuit is in a zero voltage off state when the first switch circuit in an open state receives a turn-off control signal provided by the control circuit; the inductor circuit, the first switch circuit, and the The second switching circuit generates resonance to lower the voltage of the second switching circuit to zero; when the second switching circuit in the off state receives the opening control signal provided by the control circuit, the second switching circuit is a zero voltage turn-on state, and the voltage of the second switch circuit is still zero voltage;

When the second switch circuit in the open state receives the turn-off control signal provided by the control circuit, the second switch circuit is in a zero voltage off state; the inductor circuit, the first switch circuit, and the The second switching circuit generates resonance to lower the voltage of the first switching circuit to zero; when the first switching circuit in the off state receives the opening control signal provided by the control circuit, the first switching circuit is Zero voltage turn-on state. The PWM DC pulse circuit, the coating circuit and the coating circuit are coated by the complementary control logic, so that the inductance and the two switching circuits resonate, and the switching circuit operates in a zero voltage switching state, fully utilizing the high frequency switching characteristics of the switching circuit. The power output pulse frequency reaches 200KHz, which ensures a stable arc-free environment during the process, which not only improves the production efficiency, but also improves the surface film quality of the mobile terminal structural parts of the coating process.

BRIEF abstract

Figure 1 is a schematic diagram of the principle of a vacuum coating system;

2 is a schematic structural view of a DC pulse circuit;

3 is a schematic structural diagram of a zero voltage PWM DC pulse circuit according to an embodiment of the present invention.

Preferred embodiment of the invention

In order to make the objects, the technical solutions and the advantages of the present invention more clearly, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, in the case of no conflict, the features in the embodiments and the embodiments of the present application may be arbitrarily combined with each other. These combinations are all within the scope of the invention.

The embodiment of the invention provides a pulse width modulation (PWM) DC pulse circuit, the circuit comprising: a voltage dividing capacitor circuit and a switching circuit respectively connected to the positive and negative poles of the power supply source of the PWM DC pulse circuit, The piezoelectric capacitor circuit includes a first voltage dividing capacitor circuit and a second voltage dividing capacitor circuit connected in series, the switching circuit includes a first switching circuit and a second switching circuit connected in series; the circuit further includes an inductor circuit, One end of the inductor circuit is connected to the first voltage dividing capacitor circuit and the second voltage dividing capacitor circuit, and the other end of the inductor circuit is connected to the first switch circuit and the second switch circuit; The first switching circuit and the second switching circuit are both connected to the output of the control circuit, and are both used in a zero voltage soft switching state at the time of switching.

The first switching circuit and the second switching circuit are all transistors having high frequency operating characteristics, and may be insulated gate field effect transistors (MOSFETs) or insulated gate bipolar transistors (IGBTs) or IGBT module. For MOSFETs, it can be an N-communication MOSFET, too It can be a P-channel MOSFET. When the MOSFET is the N-channel MOSFET, a gate of the MOSFET in the first switching circuit is connected to an output end of the control circuit, and a gate of the MOSFET in the second off circuit An output end of the control circuit is connected; when the MOSFET is the P-channel MOSFET, a source of the MOSFET in the first switch circuit is connected to a positive pole of the power supply, the first switch circuit a gate of the MOSFET is connected to an output end of the control circuit, a drain of the MOSFET in the second switch circuit is connected to a negative pole of the power supply, and the second switch circuit The gate of the MOSFET is connected to the output of the control circuit.

As shown in FIG. 3, it is a schematic structural diagram of a zero voltage PWM DC pulse circuit according to an embodiment of the present invention. The circuit includes a power supply 31, a first voltage dividing capacitor 32, and a second voltage dividing capacitor 33 of a PWM DC pulse circuit which are sequentially disposed. The resonant inductor 34, the first MOSFET 35, and the second MOSFET 36. The half bridge midpoint formed by the first voltage dividing capacitor 32 and the second voltage dividing capacitor 33 and the midpoint of the half bridge formed by the first MOSFET 35 and the second MOSFET 36 are connected in series with a resonant inductor 34, the gate of the first MOSFET 35 and the PWM control circuit The first PWM (PWM1) output is connected, and the second MOSFET 36 is connected to the second PWM (PWM2) output of the PWM control circuit. The positive poles of the first voltage dividing capacitor 32 are respectively connected to the positive pole of the power supply source 31 and the drain of the first MOSFET 35; the cathodes of the second voltage dividing capacitor 33 are respectively connected to the anode of the power supply source 31 and the source of the second MOSFET 36.

Of course, the MOSFET main power tube in Figure 3 can also be replaced with other power tubes, for example

IGBT or IGBT module, etc., except that the collector of the IGBT or IGBT module corresponds to the drain of the MOSFET main power tube, and the emitter of the IGBT or IGBT module corresponds to the source of the MOSFET main power tube, and the gate of the IGBT or IGBT module Corresponds to the gate of the MOSFET main power tube.

In addition, the inductor circuit may be an inductor; the inductor is configured to: resonate with the first switch circuit and the second switch circuit when the first switch circuit is changed from an on state to an off state; The voltage of the second switching circuit drops to zero; or, when the second switching circuit changes from an on state to an off state, resonates with the first switching circuit and the second switching circuit, The voltage of the first switching circuit drops to zero.

Optionally, the embodiment of the present invention further provides a coating circuit, as shown in FIG. 3, in the circuit. The load 37 is increased, which is in parallel with a second switching circuit, such as the second MOSFET 36. Wherein, when the second switching circuit is the N-channel MOSFET, a structural member in the load is connected to a drain of the MOSFET, and a plating material in the load is connected to a source of the MOSFET; When the second switching circuit is the IGBT or the IGBT module, a structural member in the load is connected to a collector of the IGBT or the IGBT module, and a coating material in the load and the IGBT or The emitters of the IGBT modules are connected.

Compared with the existing DC pulse circuit, the zero voltage PWM DC pulse circuit of the invention has a slightly complicated topology, but can ensure two switch circuits by reasonably selecting the resonant inductance parameter value and controlling the complementary PWM logic of the two switch circuits. Working in the zero voltage switching state, the high-frequency switching characteristics of the switching circuit are fully utilized, and the output pulse frequency is significantly improved, thereby improving the surface processing efficiency and greatly enhancing the film quality of the coated workpiece.

The zero voltage switching principle of MOSFET 35 and MOSFET 36 will be explained below by describing in detail the power supply operation of the present invention. The working process of the DC pulse power supply in the embodiment of the present invention can be described in six modes:

Mode 1: PWM1 provides an open control signal to control the MOSFET 35 to be turned on.

PWM2 provides a shutdown control signal that controls the MOSFET 36 to turn off. The voltage on the load 37 is the voltage of the power supply 31. The voltage across the voltage dividing capacitor 32 acts on the resonant inductor 34, causing the resonant inductor 34 to '1' to increase the force P.

Mode 2: PWM1 provides a shutdown control signal to control MOSFET 35 to begin the shutdown process. PWM2 continues to be in an inactive state and MOSFET 36 is still in the shutdown state. Since the junction capacitor voltage in parallel with MOSFET 35 cannot be mutated, the MOSFET 35 voltage rises from zero, that is, MOSFET 35 is turned off at zero voltage. At this time, the resonant inductor 34 resonates with the MOSFET 35 junction capacitance and the MOSFET 36 junction capacitance. When the MOSFET 35 voltage rises, the MOSFET 36 voltage drops. When the resonance ends, the voltage of the MOSFET 35 rises to the voltage of the power supply 31 of the PWM DC pulse circuit, and the voltage of the MOSFET 36 drops to zero. This modal time is extremely short and is the dead time of the PWM control.

Modal 3: After the modal two resonance ends, the resonant inductor 34 current and the load 37 current flow through the MOSFET 36 for the diode to continue to flow, the MOSFET36 voltage is always zero, creating conditions for the MOSFET 36 zero voltage turn-on of the modal four. Modal 4: Since modal three has guaranteed that the voltage of MOSFET36 is zero, PWM2 changes from the invalid of modal three to active, and MOSFET36 turns on zero voltage. PWM1 remains inactive and MOSFET 35 is still off. Since the voltage at this time is the voltage of the voltage dividing capacitor 33, the resonant inductor 34 current is reversely increased by the MOSFET 36.

Mode 5: PWM1 provides a shutdown control signal, MOSFET 35 is in the off state, PWM2 changes from the active state of modal three to the inactive state, and control MOSFET 36 begins to turn off. Since the junction capacitor voltage connected in parallel on MOSFET 36 cannot be abruptly changed, the voltage of MOSFET 36 rises from zero, that is, MOSFET 36 is turned off at zero voltage. At this time, the resonant inductor 34 resonates with the MOSFET 35 junction capacitance and the MOSFET 36 junction capacitance, the MOSFET 35 voltage drops, and the MOSFET 36 junction voltage rises. When the resonance ends, the MOSFET 35 voltage is zero, and the MOSFET 36 voltage is the power supply 31 voltage. This modal time is extremely short, which is the PWM control dead time.

Modal 6: After modal five resonance, when the voltage of MOSFET35 is zero, PWM1 changes from the invalid of modal five to valid, and the control MOSFET 35 is turned on, and the MOSFET is turned on at zero voltage. PWM2 continues the inactive state of modal five, and MOSFET 36 is still in the off state. At this time, the voltage of the voltage dividing capacitor 32 is applied to the resonant inductor 34, and the resonant inductor current is positively increased. At this time, the voltage on the load 37 is the voltage of the power supply 31.

Although the structure of the zero-voltage PWM DC pulse circuit of the embodiment of the present invention is slightly more complicated than the existing DC pulse power supply structure, the zero-voltage soft switching of the two MOSFET main power tubes is ensured, and the high frequency of the MOSFET main power tube is fully utilized. Characteristics, by selecting the appropriate parameters of the resonant inductor, and by adjusting the PWM frequency, the output DC pulse frequency can be continuously adjusted from 100KHz to 200KHz. The treatment of the surface of the mobile terminal related product by the DC pulse power supply of the invention can greatly improve the production efficiency, and make the surface quality of the surface of the workpiece to be processed more compact and wearable, and the service life is significantly improved.

One of ordinary skill in the art will appreciate that all or a portion of the above steps may be accomplished by a program that instructs the associated hardware, such as a read-only memory, a magnetic disk, or an optical disk. Alternatively, all or part of the steps of the above embodiments may also be implemented using one or more integrated circuits. Correspondingly, each module/unit in the foregoing embodiment may be implemented in the form of hardware, or may be implemented in the form of a software function module. The invention is not limited to any What is the combination of specific forms of hardware and software.

The above embodiments are only intended to illustrate the technical solutions of the present invention and are not to be construed as limiting the invention. It should be understood by those skilled in the art that the present invention may be modified or equivalently substituted without departing from the spirit and scope of the invention.

Industrial applicability

The PWM DC pulse circuit, the coating circuit and the coating circuit are coated by the complementary control logic, so that the inductance and the two switching circuits resonate, and the switching circuit operates in a zero voltage switching state, fully utilizing the high frequency switching characteristics of the switching circuit. The power output pulse frequency reaches 200KHz, which ensures a stable arc-free environment during the process, which not only improves the production efficiency, but also improves the surface film quality of the mobile terminal structural parts of the coating process. Therefore, the present invention has strong industrial applicability.

Claims

Claim

A pulse width modulation (PWM) DC pulse circuit, the PWM DC pulse circuit comprising: a circuit and a switching circuit, the voltage dividing capacitor circuit comprising a first voltage dividing capacitor circuit and a second voltage dividing capacitor circuit connected in series The switching circuit includes a first switching circuit and a second switching circuit connected in series; the PWM DC pulse circuit further includes an inductor circuit, one end of the inductor circuit and the first voltage dividing capacitor circuit and the second The voltage dividing capacitor circuits are all connected, and the other end of the inductor circuit is connected to the first switch circuit and the second switch circuit; the first switch circuit and the second switch circuit are both connected to the control circuit The output terminals are connected, and are all set to: at the time of switching, at a zero voltage soft switching state.

2. The PWM DC pulse circuit according to claim 1, wherein:

The first switching circuit and the second switching circuit are each a transistor having a high frequency operating characteristic.

3. The PWM DC pulse circuit according to claim 2, wherein:

The transistor is an insulated gate field effect transistor (MOSFET), and the MOSFET includes an N communication MOSFET and a P channel MOSFET, wherein:

4. The PWM DC pulse circuit according to claim 3, wherein: The MOSFET is a separate MOSFET transistor or a MOSFET module circuit in which MOSFET transistors are formed in series or in parallel.

5. The PWM DC pulse circuit of claim 2, wherein:

The transistor is an insulated gate bipolar transistor (IGBT) or an IGBT module, and the collector of the IGBT or the IGBT module in the first switching circuit is connected to an anode of the power supply, the first switch a gate of the IGBT or the IGBT module in the circuit is connected to an output end of the control circuit, and an emission stage of the IGBT or the IGBT module in the second switch circuit and a negative electrode of the power supply Connected, the IGBT of the second switching circuit or the gate of the IGBT module is connected to an output end of the control circuit.

6. The PWM DC pulse circuit of claim 5, wherein:

The IGBT or the IGBT module is an independent IGBT or IGBT module, or an IGBT module circuit in which a plurality of IGBTs or a plurality of IGBT modules are formed in series or in parallel.

7. The PWM DC pulse circuit according to claim 1, wherein:

The inductor circuit is an inductor; the inductor is configured to: resonate with the first switch circuit and the second switch circuit when the first switch circuit is changed from an on state to an off state, The voltage of the second switching circuit drops to zero; or, when the second switching circuit changes from the on state to the off state, resonates with the first switching circuit and the second switching circuit, so that the first The voltage of a switching circuit drops to zero.

8. The PWM DC pulse circuit according to claim 1, wherein:

The first voltage dividing capacitor circuit is a first voltage dividing capacitor, the second voltage dividing capacitor circuit is a second voltage dividing capacitor, and a positive pole of the first voltage dividing capacitor is connected to an anode of the power supply source, The negative pole of the second voltage dividing capacitor is connected to the negative pole of the power supply.

9. A coating circuit comprising a pulse width modulation (PWM) DC pulse circuit and a load coupled to the PWM DC pulse circuit, wherein:

The PWM DC pulse circuit includes: a voltage dividing capacitor circuit and a switching circuit respectively connected to the positive and negative poles of the power supply source of the PWM DC pulse circuit, wherein the voltage dividing capacitor circuit comprises a first voltage dividing capacitor circuit connected in series And a second voltage dividing capacitor circuit, the switching circuit includes a first switching circuit and a second switching circuit connected in series; the coating circuit further includes an inductor circuit, the electricity One end of the sensing circuit is connected to both the first voltage dividing capacitor circuit and the second voltage dividing capacitor circuit, and the other end of the inductor circuit is connected to the first switching circuit and the second switching circuit; The first switching circuit and the second switching circuit are both connected to the output end of the control circuit, and are both set to be in a zero voltage soft switching state at the time of switching; the load is connected in parallel with the second switching circuit.

10. The coating circuit according to claim 9, wherein:

When the first switching circuit and the second switching circuit are both insulated gate field effect transistors (MOSFETs), the MOSFET includes an N communication MOSFET and a P-channel MOSFET; when the MOSFET is the N-channel MOSFET The drain of the MOSFET in the first switching circuit is connected to the anode of the power supply, and the gate of the MOSFET in the first switching circuit is connected to the output of the control circuit. a source of the MOSFET in the second switching circuit is connected to a cathode of the power supply, and a gate of the MOSFET in the second switching circuit is connected to an output of the control circuit; when the MOSFET When the P-channel MOSFET is used, a source of the MOSFET in the first switching circuit is connected to a positive pole of the power supply, a gate of the MOSFET in the first switching circuit, and the control An output of the circuit is connected, a drain of the MOSFET in the second switch circuit is connected to a negative pole of the power supply, and a gate of the MOSFET in the second switch circuit and an output of the control circuit Connected to each other; Or

When the first switching circuit and the second switching circuit are both insulated gate bipolar transistors (IGBTs) or IGBT modules, the IGBT of the first switching circuit or the collector and the IGBT module An anode of the power supply is connected, a gate of the IGBT or the IGBT module in the first switch circuit is connected to an output end of the control circuit, the IGBT or the IGBT in the second switch circuit The emitter stage of the IGBT module is connected to the cathode of the power supply, and the gate of the IGBT or the IGBT module in the second switch circuit is connected to the output of the control circuit.

11. The coating circuit according to claim 9, wherein:

When the second switching circuit is the N-channel MOSFET, a structure in the load is connected to a drain of the MOSFET, and a coating material in the load is connected to the MOSFET source; or

When the second switching circuit is the IGBT or the IGBT module, in the load A structural member is coupled to the collector of the IGBT or the IGBT module, and a coating material in the load is coupled to an emitter of the IGBT or the IGBT module.

12. A method of coating a circuit according to any of claims 9-11, the method comprising:

The PWM DC pulse circuit supplies power to the load such that ions of the coating material in the load are plated on the structural member in the load under the action of electromagnetic induction; wherein the PWM DC pulse circuit is applied to the load The process of power supply includes:

When the second switch circuit in the open state receives the turn-off control signal provided by the control circuit, the second switch circuit is in a zero voltage off state; the inductor circuit, the first switch circuit, and the The second switching circuit generates resonance to lower the voltage of the first switching circuit to zero; when the first switching circuit in the off state receives the opening control signal provided by the control circuit, the first switching circuit is Zero voltage turn-on state.